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  • 1. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Ampe, J.
    Anderson, B.
    Johannesson, G.
    Johnson, A. S.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ziegler, M.
    McGlynn, Sinéad
    University College Dublin, Ireland.
    Ylinen, Tomi
    Hogskolan i Kalmar.
    Moretti, Elena
    Max-Planck-Institut-fur-Physik, Germany.
    The on-orbit calibration of the Fermi Large Area Telescope2009In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 32, no 3-4, p. 193-219Article in journal (Refereed)
    Abstract [en]

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.

  • 2. Abdo, A. A.
    et al.
    Ackermann, M.
    Atwood, W. B.
    Bagagli, R.
    Johnson, A. S.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ziegler, M.
    Conrad, Jan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Mc Glynn, Sinéad
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sellerholm, Alexander
    FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE VELA PULSAR2009In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 696, no 2, p. 1084-1093Article in journal (Refereed)
    Abstract [en]

    The Vela pulsar is the brightest persistent source in the GeV sky and thus is the traditional first target for new gamma-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure and early sky survey scanning. We have used the Vela signal to verify Fermi timing and angular resolution. The high-quality pulse profile, with some 32,400 pulsed photons at E >= 0.03 GeV, shows new features, including pulse structure as fine as 0.3 ms and a distinct third peak, which shifts in phase with energy. We examine the high-energy behavior of the pulsed emission; initial spectra suggest a phase-averaged power-law index of Gamma = 1.51(-0.04)(+0.05) with an exponential cutoff at E-c = 2.9 +/- 0.1 GeV. Spectral fits with generalized cutoffs of the form e(-(E/Ec)b) require b <= 1, which is inconsistent with magnetic pair attenuation, and thus favor outer-magnetosphere emission models. Finally, we report on upper limits to any unpulsed component, as might be associated with a surrounding pulsar wind nebula.

  • 3. Andersson, V.
    et al.
    Chen, P.
    Kamae, T.
    Madejski, G.
    Mizuno, T.
    Ng, J. S. T.
    Suhonen, M.
    Tajima, H.
    Thurston, T.
    Bogaert, G.
    Fukazawa, Y.
    Saito, Y.
    Takahashi, T.
    Barbier, L.
    Bloser, P.
    Cline, T.
    Harding, A.
    Hunter, S.
    Krizmanic, J.
    Mitchell, J.
    Streitmatter, R.
    Fernholz, R.
    Groth, E.
    Marlow, D.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Bjornsson, C. -I
    Fransson, C.
    Larsson, S.
    Ryde, Felix
    Stockholm University.
    Arimoto, M.
    Ikagawa, T.
    Kanai, Y.
    Kataoka, J.
    Kawai, N.
    Yatsu, Y.
    Gunji, S.
    Sakurai, H.
    Yamashita, Y.
    Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)2005In: Proceedings of the 22nd Texas Symposium on Relativistic Astrophysics at Stanford, 2005, p. 736-743Conference paper (Refereed)
    Abstract [en]

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10 % polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view (~ 5 deg2) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected.

  • 4. Arimoto, M.
    et al.
    Kanai, Y.
    Ueno, M.
    Kataoka, J.
    Kawai, N.
    Tanaka, T.
    Yamamoto, K.
    Takahashi, H.
    Mizuno, T.
    Fukazawa, Y.
    Axelsson, Magnus
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kiss, Mózsi
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Marini Bettolo, Cecilia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Chen, P.
    Craig, B.
    Kamae, T.
    Madejski, G.
    Ng, J. S. T.
    Rogers, R.
    Tajima, H.
    Thurston, T. S.
    Saito, Y.
    Takahashi, T.
    Gunji, S.
    Bjornsson, Ca.
    Larsson, S.
    Ryde, Felix
    Bogaert, G.
    Varner, G.
    Performance assessment study of the balloon-borne astronomical soft gamma-ray polarimeter PoGOLite2007In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 40, no 2, p. 438-441Article in journal (Refereed)
    Abstract [en]

    Measurements of polarization play a crucial role in the understanding of the dominant emission mechanism of astronomical sources. Polarized Gamma-ray Observer-Light version (PoGOLite) is a balloon-borne astronomical soft gamma-ray polarimeter at the 25-80 keV band. The PoGOLite detector consists of a hexagonal close-packed array of 217 Phoswich detector cells (PDCs) and side anti-coincidence shields (SASs) made of BGO crystals surrounding PDCs. Each PDC consists of a slow hollow scintillator, a fast scintillator and a BGO crystal that connects to a photomultiplier tube at the end. To examine the PoGOLite's capability and estimate the performance, we conducted experiments with the PDC using radioisotope 241Am. In addition, we compared this result with performance expected by Monte Carlo simulation with Geant4. As a result, we found that the actual PDC has the capability to detect a 100 m Crab source until 80 keV.

  • 5. Atwood, W. B.
    et al.
    Abdo, A. A.
    Ackermann, M.
    Althouse, W.
    Johnson, A. S.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    Ziegler, M.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Conrad, Jan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Hjalmarsdotter, Linnea
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Moretti, Elena
    University and INFN of Trieste.
    THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION2009In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 697, no 2, p. 1071-1102Article in journal (Refereed)
    Abstract [en]

    The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy gamma-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (4) localize point sources to 0.3-2 arcmin, (5) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (6) measure the diffuse isotropic gamma-ray background up to TeV energies, and (7) explore the discovery space for dark matter.

  • 6. Axelsson, Magnus
    et al.
    Engdegard, Olle
    KTH, School of Engineering Sciences (SCI), Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Larsson, S.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Hjalmarsdotter, L.
    Kiss, Mószi
    KTH, School of Engineering Sciences (SCI), Physics.
    Bettolo, C. Marini
    KTH, School of Engineering Sciences (SCI), Physics.
    Arimoto, M.
    Bjornsson, C. I.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics.
    Fukazawa, Y.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Kawal, N.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Madejski, G.
    Mizuno, T.
    Ng, J.
    Tajima, H.
    Takahashi, T.
    Tanaka, T.
    Ueno, M.
    Varner, G.
    Yamamoto, K.
    Measuring energy dependent polarization in soft gamma-rays using compton scattering in PoGOLite2007In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 28, no 3, p. 327-337Article in journal (Refereed)
    Abstract [en]

    Linear polarization in X-and gamma-rays is an important diagnostic of many astrophysical sources, foremost giving information about their geometry, magnetic fields, and radiation mechanisms. However, very few X-ray polarization measurements have been made, and then only mono-energetic detections, whilst several objects are assumed to have energy dependent polarization signatures. In this paper, we investigate whether detection of energy dependent polarization from cosmic sources is possible using the Compton technique, in particular with the proposed PoGOLite balloon-experiment, in the 25-100 keV range. We use Geant4 simulations of a PoGOLite model and input photon spectra based on Cygnus X-1 and accreting magnetic pulsars (100 mCrab). Effective observing times of 6 and 35 h were simulated, corresponding to a standard and a long duration flight, respectively. Both smooth and sharp energy variations of the polarization are investigated and compared to constant polarization signals using chi-square statistics. We can reject constant polarization, with energy, for the Cygnus X-1 spectrum (in the hard state), if the reflected component is assumed to be completely polarized, whereas the distinction cannot be made for weaker polarization. For the accreting pulsar, constant polarization can be rejected in the case of polarization in a narrow energy band with at least 50% polarization, and similarly for a negative step distribution from 30% to 0% polarization.

  • 7. Balcerzyk, M.
    et al.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Moszynski, M.
    Kapusta, M.
    Szawlowski, M.
    Energy resolution and light yield non-proportionality of ZnSe: Te scintillator studied by large area avalanche photodiodes and photomultipliers2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 482, no 3, p. 720-727Article in journal (Refereed)
    Abstract [en]

    The ZnSe: Te scintillator has been studied by means of a photomultiplier with an extended bialkali photocathode, a large area avalanche photodiode (LAAPD) and a PIN photodiode. The light output was determined to be 28 300+/-1700 photons/MeV. Results indicate good proportionality for light output versus gamma-ray energy. Measurements of the 662 keV gamma-ray energy spectrum recorded using a LAAPD resulted in an energy resolution of 5.4+/-0.3%. Based on these results, an intrinsic energy resolution of 3.3+/-0.7% has been calculated.

  • 8.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederkall, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    van der Marel, J.
    Molnar, J.
    Novak, D.
    Sohler, D.
    Steen, M.
    Uhlen, P.
    A TOF-PET system for educational purposes2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 477, no 03-jan, p. 82-87Article in journal (Refereed)
    Abstract [en]

    A TOF-PET system has been designed and constructed for educational purposes. The aim of this system is to demonstrate the possibilities of positron emission tomography in general and the time-of-flight method in particular to the students of various courses at the Royal Institute of Technology, Stockholm, Sweden. The set-up consists of 48 small BaF2 crystals coupled to fast photomultipliers placed in a ring geometry. The signals of the photomultipliers are fed into fast constant fraction discriminators (CFD). The outputs of these are directed to a specially designed logic VME unit. which combines the CFD signals of 6 neighbouring channels to one signal by adding a different delay to each channel. The logic circuitry produces a prompt pulse for each event that serves as the start pulse for the 8-channel fast TDC. The delayed pulses act as the stop pulses for the TDC. In a computer. the measured times are converted into information about which the photomultipliers fired with the difference in the time of flight. The set-up is described and the results are presented.

  • 9.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    van der Marel, J
    Molnar, J
    Novak, D
    Sohler, D
    Steen, M
    Uhlen, P
    An educational tool for demonstrating the TOF-PET technique2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 471, no 1-2, p. 200-204Article in journal (Refereed)
    Abstract [en]

    A detector system for positron emission tomography with time-of-flight capability has been built to serve as an educational tool for undergraduate students. The set-up consists of 48 BaF2 scintillator crystals, each coupled to a fast photo-multiplier tube, mounted in a circular geometry. The analogue detector pulses are handled by fast constant fraction discriminators. A dedicated unit reduces the 48 channels to eight channels via delay-fine encoding, and the signals are then fed to an eight channel fast time-to-digital converter. A VME processor sorts the events and sends them to a workstation where the coincident events are extracted. The time resolution of the detectors together with fast VME based electronics allows for time-of-flight measurements to improve on the signal-to-noise ratio in the, reconstructed images. The system can be used for different types of exercises for the students, varying from the fundamentals of scintillator detectors to advanced image reconstruction. The set-up is described and some results are presented. (C) 2001 Elsevier Science B.V. All rights reserved.

  • 10. Carasco, C.
    et al.
    Perot, B.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Le Tourneur, P.
    Lhuissier, M.
    Colonna, A.
    Tintori, C.
    Peerani, P.
    Sequeira, V.
    Salvato, M.
    et al,
    In-field tests of the EURITRACK tagged neutron inspection system2008In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 588, no 3, p. 397-405Article in journal (Refereed)
    Abstract [en]

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been designed to complement X-ray scanners in the detection of explosives and other illicit materials hidden in cargo containers. The containers are interrogated by a 14-MeV tagged neutron beam at any suspect position in the X-ray image. Interrogation of a specific volume element with tagged neutrons yields information about the chemical composition of the material. Implementation and performance tests of the EURITRACK system in the Port of Rijeka in Croatia are described. Cargo container inspection results are reported and discussed.

  • 11. Fahlander, C.
    et al.
    Palacz, M.
    Rudolph, D.
    Sohler, D.
    Blomqvist, J.
    Lagergren, K.
    Norlin, L. O.
    Nyberg, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Wolinska, M.
    et al,
    Excited states in Sn-103: Neutron single-particle energies with respect to Sn-1002001In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6302, no 2Article in journal (Refereed)
    Abstract [en]

    Gamma-ray lines from Sn-103 have been identified for the first time using EUROBALL and ancillary detectors. The level scheme of Sn-103 has been established by means of particle-gated gamma gamma coincidences. The energy spacing between the g(7/2) and d(5/2) neutron single-particle orbitals is determined from the excited states in Sn-103.

  • 12. Gavler, S. B.
    et al.
    Carius, S.
    Carlson, P.
    Johansson, G.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Radiation tests of CsI(Tl) crystals for the GLAST satellite mission2005In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 545, no 3, p. 842-851Article in journal (Refereed)
    Abstract [en]

    The electromagnetic calorimeter of the Gamma-ray Large Area Space Telescope (GLAST) consists of 16 towers of CsI(Tl) crystals. Each tower contains 8 layers of crystals (each 326.0x26.7 x 19.9mm(3)) arranged in a hodoscopic fashion. The crystals are read out at both ends with PIN diodes. Crystals produced by Amcrys-H are used. As a part of the quality control procedure during crystal production, samples from the uncut boules were systematically irradiated with gamma-rays from a 60Co source. The decrease in light yield due to radiation damage was measured, determining the radiation hardness of the boule. All boule samples passed the radiation hardness requirements, showing an average decrease in light yield of (14 +/- 4)% after having received a dose of 200Gy. Studies have also been carried out to verify the correspondence between the post-irradiation properties of the boule samples and the full-size crystals which are subsequently cut from the boule. A crystal log was irradiated with gamma-rays from a (CO)-C-60 source and showed a decrease in light yield of (24 +/- 4)% after a dose of 180 Gy. A full-size crystal was also irradiated with a 180 MeV proton beam and the radiation induced attenuation and induced radioactivity was studied. The light yield was found to have decreased with (22 +/- 5)% after 175 Gy, and the dominant radioactive isotopes were identified.

  • 13. Gierlik, M.
    et al.
    Batsch, T.
    Moszynski, M.
    Szczesniak, T.
    Wolski, D.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Perot, B.
    Perret, G.
    Comparative study of large NaI(Tl) and BGO scintillators for the EURopean Illicit TRAfficking Countermeasures Kit project2006In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, no 3, p. 1737-1743Article in journal (Refereed)
    Abstract [en]

    The Tagged Neutron Inspection System, which is the principle of the EURITRACK project, requires efficient and inexpensive gamma-ray detectors. For this purpose, properties of 3 x 3 and 5 x 5 cylindrical BGO and NaI(TI) scintillators and of a 5 x 5 x 10 rectangular NaI(TI) scintillator were determined. 14 Light yield, energy and time resolution of the investigated crystals at the energy of few MeVs of gamma-rays are emphasized. Additionally, the crystals efficiencies calculated with Monte Carlo simulations are compared to peak-to-total ratios obtained experimentally for various combinations of PMTs and the scintillators.

  • 14. Gierlik, M.
    et al.
    Batsch, T.
    Moszyński, M.
    Szczȩśniak, T.
    Wolski, D.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics.
    Perot, B.
    Perret, G.
    Comparative study of large NaI(Tl) and BGO scintillators for the EURopean illicit TRAfficking countermeasures kit project2005Conference paper (Refereed)
    Abstract [en]

    One of the essential requirements of the Tagged Neutron Inspection System, which is the principle of the EURITRACK project, is an efficient and inexpensive gamma ray detector. For this purpose properties of cylindrical 3"×3" and 5"×5" BGO, and 3"×3", two different 5"×5", and a rectangular 5"×5" ×10" NaI(Tl) scintillators were explored. In this communication we report on light yield, energy and time resolution of the investigated crystals at high energies of γ-rays. Additionally, results of Monte Carlo simulations of the crystals' efficiencies are compared to peak-to-total ratios obtained experimentally for various combinations of PMTs and the scintillators.

  • 15. Greiner, J.
    et al.
    Mannheim, K.
    Aharonian, F.
    Ajello, M.
    Balasz, L. G.
    Barbiellini, G.
    Bellazzini, R.
    Bishop, S.
    Bisnovatij-Kogan, G. S.
    Boggs, S.
    Bykov, A.
    Dicocco, G.
    Diehl, R.
    Elsässer, D.
    Foley, S.
    Fransson, C.
    Gehrels, N.
    Hanlon, L.
    Hartmann, D.
    Hermsen, W.
    Hillebrandt, W.
    Hudec, R.
    Iyudin, A.
    Jose, J.
    Kadler, M.
    Kanbach, G.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kiener, J.
    Klose, S.
    Kreykenbohm, I.
    Kuiper, L. M.
    Kylafis, N.
    Labanti, C.
    Langanke, K.
    Langer, N.
    Larsson, S.
    Leibundgut, B.
    Laux, U.
    Longo, F.
    Maeda, K.
    Marcinkowski, R.
    Marisaldi, M.
    McBreen, B.
    McBreen, S.
    Meszaros, A.
    Nomoto, K.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Peer, A.
    Pian, E.
    Prantzos, N.
    Raffelt, G.
    Reimer, O.
    Rhode, W.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Schmidt, C.
    Silk, J.
    Shustov, B. M.
    Strong, A.
    Tanvir, N.
    Thielemann, F. -K
    Tibolla, O.
    Tierney, D.
    Trümper, J.
    Varshalovich, D. A.
    Wilms, J.
    Wrochna, G.
    Zdziarski, A.
    Zoglauer, A.
    GRIPS - Gamma-Ray Imaging, Polarimetry and Spectroscopy2012In: Experimental astronomy (Print), ISSN 0922-6435, E-ISSN 1572-9508, Vol. 34, no 2, p. 551-582Article in journal (Refereed)
    Abstract [en]

    We propose to perform a continuously scanning all-sky survey from 200 keV to 80 MeV achieving a sensitivity which is better by a factor of 40 or more compared to the previous missions in this energy range (COMPTEL, INTEGRAL; see Fig. 1). These gamma-ray observations will be complemented by observations in the soft X-ray and (near-)infrared region with the corresponding telescopes placed on a separate satellite. The Gamma-Ray Imaging, Polarimetry and Spectroscopy ("GRIPS") mission with its three instruments Gamma-Ray Monitor (GRM), X-Ray Monitor (XRM) and InfraRed Telescope (IRT) addresses fundamental questions in ESA's Cosmic Vision plan. Among the major themes of the strategic plan, GRIPS has its focus on the evolving, violent Universe, exploring a unique energy window. We propose to investigate γ-ray bursts and blazars, the mechanisms behind supernova explosions, nucleosynthesis and spallation, the enigmatic origin of positrons in our Galaxy, and the nature of radiation processes and particle acceleration in extreme cosmic sources including pulsars and magnetars. The natural energy scale for these non-thermal processes is of the order of MeV. Although they can be partially and indirectly studied using other methods, only the proposed GRIPS measurements will provide direct access to their primary photons. GRIPS will be a driver for the study of transient sources in the era of neutrino and gravitational wave observatories such as IceCUBE and LISA, establishing a new type of diagnostics in relativistic and nuclear astrophysics. This will support extrapolations to investigate star formation, galaxy evolution, and black hole formation at high redshifts.

  • 16.
    Ideguchi, Eiji
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Tomov, V
    Hausmann, M
    Jungclaus, A
    Napoli, R
    Carpenter, P
    Janssens, F
    Kondev, G
    Lauritsen, T
    Lister, J
    Seweryniak, D
    Wiedenhoever, I
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Superdeformation in 91Tc2000In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 492, no 3-4, p. 245-253Article in journal (Refereed)
    Abstract [en]

    A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 17.
    Jackson, Miranda
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kiss, Mózsi
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Mallol, Pau
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Bettolo, Cecilia Marini
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Rydström, Stefan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Varner, G.
    Yoshida, H.
    PoGOLite: a balloon-borne soft gamma-ray polarimeter2009In: 2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5  / [ed] Yu B, 2009, p. 449-453Conference paper (Refereed)
    Abstract [en]

    PoGOLite is a balloon-borne X-ray polarimeter, designed to measure the polarization of 25-80 keV X-rays. It is scheduled for a pathfinder flight in August 2010. This paper outlines the scientific motivation and the status of preparations of the payload.

  • 18. Kamae, Tuneyoshi
    et al.
    Andersson, Viktor
    KTH, School of Engineering Sciences (SCI), Physics.
    Arimoto, Makoto
    Axelsson, Magnus
    Bettolo, Cecilia Marini
    KTH, School of Engineering Sciences (SCI), Physics.
    Björnsson, Claes-Ingvar
    Bogaert, Gilles
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Craig, William
    Ekeberg, Tomas
    KTH, School of Engineering Sciences (SCI), Physics.
    Engdegård, Olle
    KTH, School of Engineering Sciences (SCI), Physics.
    Fukazawa, Yasushi
    Gunji, Shuichi
    Hjalmarsdotter, Linnea
    Iwan, Bianca
    KTH, School of Engineering Sciences (SCI), Physics.
    Kanai, Yoshikazu
    Kataoka, Jun
    Kawai, Nobuyuki
    Kazejev, Jaroslav
    KTH, School of Engineering Sciences (SCI), Physics.
    Kiss, Mozsi
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Larsson, Stefan
    KTH, School of Engineering Sciences (SCI), Physics.
    Madejski, Grzegorz
    Mizuno, Tsunefumi
    Ng, Johnny
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Rydé, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Suhonen, Markus
    KTH, School of Engineering Sciences (SCI), Physics.
    TaJima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Tanaka, Takuya
    Thurston, Timothy
    Ueno, Masaru
    Varneri, Gary
    Yamamoto, Kazuhide
    Yamashita, Yuichiro
    Ylinen, Tomi
    KTH, School of Engineering Sciences (SCI), Physics.
    Yoshida, Hiroaki
    PoGOLite - A high sensitivity balloon-borne soft gamma-ray polarimeter2008In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 30, no 2, p. 72-84Article in journal (Refereed)
    Abstract [en]

    We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200 mCrab point-like sources between 25 and 80 keV in one 6-h flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. Synchrotron radiation, inverse Compton scattering and propagation through high magnetic fields are likely to produce high degrees of polarisation in the energy band of the instrument. We demonstrate, through tests at accelerators, with radioactive sources and through computer simulations, that PoGOLite will be able to detect degrees of polarisation as predicted by models for several classes of high energy sources. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles while securing a large effective area has been the greatest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow Held of view (FWHM = 1.25 msr, 2.0 deg x 2.0 deg) obtained with detector cells and the use of thick background shields warrant a large effective area for polarisation measurements (similar to 228 cm(2) at E = 40 keV) without sacrificing the signal-to-noise ratio. Simulation studies for an atmospheric overburden of 3-4 g/cm(2) indicate that neutrons and gamma-rays entering the PDC assembly through the shields are dominant backgrounds. Off-line event selection based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a similar to 100 mCrab source between 25 and 50 keV. A 6-h observation of the Crab pulsar will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma significance; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. Long-duration flights will measure the dependence of the polarisation across the cyclotron absorption line in Hercules X-1. A scaled-down instrument will be flown as a pathfinder mission from the north of Sweden in 2010. The first science flight is planned to take place shortly thereafter.

  • 19. Kanai, Y.
    et al.
    Kataoka, J.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Rydstrom, S.
    Takahashi, T.
    Thurston, T. S.
    Varner, G.
    Kiss, Mózsi
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Marini Bettolo, Cecilia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Larsson, Stefan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    A Monte Carlo method for calculating the energy response of plastic scintillators to polarized photons below 100 keV2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 600, no 3, p. 609-617Article in journal (Refereed)
    Abstract [en]

    The energy response of plastic scintillators (Eljen Technology EJ-204) to polarized soft gamma-ray photons below 100 keV has been studied, primarily for the balloon-borne polarimeter, PoGOLite. The response calculation includes quenching effects due to low-energy recoil electrons and the position dependence of the light collection efficiency in a 20 cm long scintillator rod. The broadening of the pulse-height spectrum, presumably caused by light transportation processes inside the scintillator, as well as the generation and multiplication of photoelectrons in the photomultiplier tube, were studied experimentally and have also been taken into account. A Monte Carlo simulation based on the Geant4 toolkit was used to model photon interactions in the scintillators. When using the polarized Compton/Rayleigh scattering processes previously corrected by the authors, scintillator spectra and angular distributions of scattered polarized photons could clearly be reproduced, in agreement with the results obtained at a synchrotron beam test conducted at the KEK Photon Factory. Our simulation successfully reproduces the modulation factor, defined as the ratio of the amplitude to the mean of the distribution of the azimuthal scattering angles, within similar to 5% (relative). Although primarily developed for the PoGOLite mission, the method presented here is also relevant for other missions aiming to measure polarization from astronomical objects using plastic scintillator scatterers.

  • 20. Kanai, Y.
    et al.
    Ueno, M.
    Kataoka, J.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    et al,
    Beam test of a prototype phoswich detector assembly for the PoGOLite astronomical soft gamma-ray polarimeter2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 570, no 1, p. 61-71Article in journal (Refereed)
    Abstract [en]

    We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer-Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4%, 35.8% and 37.2% at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations.

  • 21. Kapusta, M.
    et al.
    Moszynski, M.
    Balcerzyk, M.
    Braziewicz, J.
    Wolski, D.
    Pawelke, J.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Comparison of the scintillation properties of LSO: Ce manufactured by different laboratories and of LGSO : Ce2000In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 47, no 4, p. 1341-1345Article in journal (Refereed)
    Abstract [en]

    We measured photoelectron yield, light output, decay times of the light pulses, cerium concentration, energy resolution and time resolution of LSO:Ce manufactured by different laboratories and LGSO:Ce. The LSO samples show excellent scintillation properties: high light output, close to 30,000 ph/MeV and good energy resolution of 7.3% FWHM for Cs-137 gamma-source full energy peak. Time resolution measured in geometry fulfilling the PET scanners requirements is equal to 450 ps. We also present results fi om the measurements with LGSO:Ce by Hitachi Chemical Co., which is of similar chemical composition to LSO. LGSO, at present stage of development, shows about 20% lower light output than LSO and energy resolution of 12.4% FWHM for 662 keV gamma-rays. LSO crystals used in our studies posses similar in scintillation properties, although we suppose that the details of the productions method are different due to the differences in Ce concentration. LGSO is a new and very promising scintillator due to lower background radiation in comparison to LSO, but it features worse energy resolution and smaller number of photoelectrons.

  • 22.
    Kiss, Mózsi
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Larsson, S.
    Arimoto, M.
    Axelsson, A.
    Marini Bettolo, Cecilia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Bogaert, G.
    Floren, H. -G
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Kawai, N.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kurita, K.
    Madejski, G.
    Mizuno, T.
    Olofsson, G.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Rydström, Stefan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Ueno, M.
    Umeki, Y.
    Varner, G.
    Yoshida, H.
    The PoGOLite balloon-borne soft gamma-ray polarimeter2008In: COOL DISCS, HOT FLOWS: THE VARYING FACES OF ACCRETING COMPACT OBJECTS / [ed] Axelsson, M, 2008, Vol. 1054, p. 225-232Conference paper (Refereed)
    Abstract [en]

    Linearly polarized radiation in the hard X-ray/soft gamma-ray band is expected from a large variety of astronomical sources. We discuss the importance of polarimetric studies for several classes of sources - pulsars, accreting black holes. magnetic neutron stars and jets from active galaxies - and then describe PoGOLite, a balloon-borne instrument which is currently under construction and will be able to measure the polarization of electromagnetic radiation from such extra-solar objects in the energy range 25-80 keV.

  • 23.
    Klamra, Wlodzimierz
    et al.
    KTH, Superseded Departments, Physics.
    Asztalos, S.
    Becker, J. A.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Clark, R. M.
    Deleplanque, M. A.
    Diamond, R. M.
    Fallon, P.
    Farris, L. P.
    Lee, I. Y.
    Macchiavelli, A. O.
    Macleod, R. W.
    Sarantites, D. G.
    Stephens, F. S.
    High-spin multiparticle-hole excitations in Eu-1482001In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 10, no 1, p. 11-12Article in journal (Refereed)
    Abstract [en]

    Studies by means of 155 MeV Al-27 bombardment on a Te-130 target revealed in Eu-148 high-spin structures up to spin 31 (n) over tilde, in addition to a cascade extended to the 11088.1 keV excitation. The observed levels are tentatively assigned as complex multiparticle-hole proton and neutron configurations.

  • 24.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Balcerzyk, M.
    Czarnacki, W.
    Kozlov, V.
    Moszynski, M.
    Syntfeld-Kazuch, A.
    Szczesniak, T.
    Light yield non-proportionality of undoped YAP scintillator2009Article in journal (Refereed)
    Abstract [en]

    Scintillation properties of undoped YAP crystal were studied. The emission spectra show a very intense light component at 360 nm. Analysis of the light pulse shape resulted in five components, four of them, with time constants of 38+/-2 ns, 92+/-3 ns, 7.5+/-0.5 mu s and 24+/-3 mu s, representing high light intensity. The light yield was found to be temperature dependent, N-ph=3090+/-130 ph/MeV at liquid nitrogen temperature and N-ph=1440+/-60 ph/MeV at room temperature. Also the light yield non-proportionality shows temperature dependence and is more pronounced at room temperature.

  • 25.
    Klamra, Wlodzimierz
    et al.
    KTH, Superseded Departments, Physics.
    Balcerzyk, M.
    Kapusta, M.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Moszynski, M.
    Norlin, L. O.
    Novak, D.
    Possnert, G.
    Studies of scintillation light nonproportionality of ZnSe(Te), CsI(Tl) and YAP(Ce) crystals using heavy ions2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 484, no 03-jan, p. 327-332Article in journal (Refereed)
    Abstract [en]

    The scintillation light yield for ZnSe(Te), CsI(T1) and YAP(Ce) crystals have been studied with alpha particles, C-12 and Br-81 in the energy region 2.8-42.2 MeV. A nonproportional behavior was observed, mostly pronounced for alpha particles on YAP(Ce). The results are understood in terms of delta-rays effect.

  • 26.
    Klamra, Wlodzimierz
    et al.
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Moszynski, M.
    Norlin, L. O.
    Novak, D.
    Possnert, G.
    Response of BaF2 and YAP: Ce to heavy ions2000In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 444, no 3, p. 626-630Article in journal (Refereed)
    Abstract [en]

    The light output and energy resolution for BaF2 and YAP:Ce have been measured with O-16, Cl-35 and Br-79 in the energy region 8.5-34 MeV. Both crystals show a nonproportional light yield response, mostly pronounced for the lighter ions.

  • 27.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sibczynski, P.
    Moszynski, M.
    Czarnacki, W.
    Kozlov, V.
    Extensive studies on light yield non-proportional response of undoped CeF3 at room and liquid nitrogen temperatures2013In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 8, no 6, p. P06003-Article in journal (Refereed)
    Abstract [en]

    In this paper properties of various undoped CeF3 scintillators were investigated at room and liquid nitrogen (LN2) temperatures. The study was focused on measurements of radioluminescence spectra, decay time, non-proportional response to X-and gamma-rays, energy and intrinsic resolution at different temperature environment. Surprisingly, all the tested pure CeF3 crystals show non-proportional response up to 5.1 MeV gamma ray energy, which is contrary to the typical nonproportionality observed below 100 keV for most of the inorganic scintillators. The investigation of the phenomenon occurring in CeF3 scintillators would be another step to get a better knowledge of the scintillators nature, which still has not been entirely understood.

  • 28.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sibczynski, P.
    Moszynski, M.
    Kozlov, V.
    Light yield nonproportionality of doped CeF3 scintillators2014In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, p. P07013-Article in journal (Refereed)
    Abstract [en]

    In this paper measurements of emission spectra, light output and nonproportional response of CeF3 scintillators doped with Ca, Sr, Ba and Pr were conducted. Results showed degradation of the light output for the doped samples in comparison with an undoped CeF3. For each scintillator the nonproportional response on gamma radiation showed unusual lack of saturation at 100 keV, as observed previously for undoped CeF3 samples.

  • 29.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sibczynski, P.
    Moszynski, M.
    Kozlov, V.
    Study of undoped CeF3 scintillators at room and liquid nitrogen temperature2012In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference record (NSS/MIC), IEEE , 2012, p. 315-317Conference paper (Refereed)
    Abstract [en]

    In this paper properties of various undoped CeF3 scintillators were investigated at room and liquid nitrogen (LN2) temperature. The study was focused on measurements of radioluminescence spectra, decay time, non-proportional response on X- and γ-rays and energy resolution at different temperature environment. Surprisingly, the pure CeF3 crystals show comparable non-proportionality curves, which are very similar to that presented by inorganic scintillators. The investigation of the phenomenon occurring in CeF3 scintillators would be another step to get a better knowledge of the scintillators nature, which still haven't been entirely understood.

  • 30.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Szczesniak, T.
    Moszynski, M.
    Iwanowska, J.
    Swiderski, L.
    Syntfeld-Kazuch, A.
    Shlegel, V. N.
    Vasiliev, Ya. V.
    Galashov, E. N.
    Properties of CdWO4 and ZnWO4 at Liquid Nitrogen Temperature2009In: 2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5   / [ed] Yu B, 2009, p. 1561-1565Conference paper (Refereed)
    Abstract [en]

    Two samples of 10 mm diameter and 10 mm height CdWO4 (CdWO) and ZnWO4 (ZnWO) scintillators were studied at room (RT) and liquid nitrogen (LN2) temperature. At room temperature the crystals were coupled to a Photonis XP3212 photomultiplier. During experiments in liquid nitrogen a Large Area Avalanche Photodiode (LAAPD) was used as a photodetector. Measurements of light output, non-proportionality of the light yield and intrinsic resolution as a function of gamma-ray energies were performed at both temperatures. The non-proportionality for the two crystals, likely CaWO4, reveals temperature dependence, to reach the same values at LN2 temperature. Intrinsic energy resolution for both crystals was also changed at LN2 comparing to the data collected at RT. The intrinsic energy resolution was improved below 100 keV and deteriorated for higher energies.

  • 31.
    Klamra, Wlodzimierz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Szczesniak, T.
    Moszynski, M.
    Iwanowska, J.
    Swiderski, L.
    Syntfeld-Kazuch, A.
    Shlegel, V. N.
    Vasiliev, Ya V.
    Galashov, E. N.
    Properties of CdWO4 and ZnWO4 scintillators at liquid nitrogen temperature2012In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 7, no 3, p. P03011-Article in journal (Refereed)
    Abstract [en]

    Two samples of 10 mm diameter and 10 mm height CdWO4 and ZnWO4 scintillators were studied at room and liquid nitrogen temperatures. At room temperature the crystals were coupled to a Photonis XP3212 photomultiplier. During experiments at low temperatures a Large Area Avalanche Photodiode was used as a photodetector. Measurements of light output, c of the light yield and intrinsic resolution as a function of gamma-ray energies were performed at both temperatures. The non-proportionality for the two crystals reveals temperature dependence, showing a more proportional behavior at liquid nitrogen temperature. Intrinsic energy resolution values for both crystals also show temperature dependence.

  • 32. Mach, H.
    et al.
    Lewitowicz, M.
    Stanoiu, M.
    Becker, F.
    Blomqvist, J.
    Borge, M. J. G.
    Boutami, R.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Dlouhy, Z.
    Fogelberg, B.
    Fraile, L. M.
    Georgiev, G.
    Grawe, H.
    Grzywacz, R.
    Johansson, P. L.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Lukyanov, S.
    Mineva, M.
    Mrazek, J.
    Neyens, G.
    Santos, F. D.
    Pfutzner, M.
    Penionzhkevich, Y. E.
    Ramstrom, E.
    Sawicka, M.
    Coupling of valence particles/holes to Ni-68,Ni-70 studied via measurements of the B(E2) strength in Ni-67,Ni-69,Ni-70 and Cu-712003In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 719, p. 213C-216CArticle in journal (Refereed)
  • 33. Mach, H.
    et al.
    Walker, P. M.
    Julin, R.
    Leino, M.
    Juutinen, S.
    Stanoiu, M.
    Podolyak, Z.
    Wood, R.
    Bruce, A. M.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cameron, J. A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ekman, J.
    Fogelberg, B.
    Greenless, P. T.
    Hellström, M.
    Jones, P.
    Klamra, Wlodzimierz
    Lagergren, K.
    Leppanen, A. P.
    Nieminen, P.
    Orlandi, R.
    Pakarinen, J.
    Rahkila, P.
    Rudolph, D.
    Simpson, G.
    Uusitalo, J.
    Wheldon, C.
    Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei2005In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, no 10, p. S1421-S1426Article in journal (Refereed)
    Abstract [en]

    Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for Mg-32 and Pd-96, they include the first determination of the half-life of the 8(+) state in Ge-80, T-1/2 = 2.95(6) ns, and significantly more precise results for Mn-51 (3680 keV level) and V-48 (421 keV level), T-1/2 = 1760(40) ps and T-1/2.

  • 34.
    Marini Bettolo, Cecilia
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kiss, Mózsi Bank
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics.
    Siegl, Martin
    KTH, School of Engineering Sciences (SCI), Physics.
    The BGO anticoincidence system of the PoGOLite balloon-borne soft gamma-ray polarimeter2007In: Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007 / [ed] Rogelio Caballero, Juan Carlos D’Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia, Universidad Nacional Autonoma de Mexico , 2007, Vol. 2, p. 483-486Conference paper (Refereed)
    Abstract [en]

    The PoGOLite balloon-borne experiment applies well-type phoswich detector technology tomeasurements of soft gamma-ray polarization in the 25 keV - 80 keV energy range. The polarization isdetermined using Compton scattering and photoelectric absorption in an array of 217 plastic scintillators.This sensitive volume is surrounded by a segmented bismuth germanate oxide (BGO) anticoincidenceshield, designed to reduce background from charged cosmic rays, primary and atmospheric gamma-rays,and atmospheric and instrumental neutrons. A total of 379 BGO crystals with three different geometriesare used, giving an overall mass of approximately 250 kg. Tests of the BGO crystals are described andthe overall design of the anticoincidence shield is reviewed.

  • 35. Mizuno, T.
    et al.
    Arimoto, M.
    Axelsson, Magnus
    Stockholm University.
    Björnsson, C. -I
    Bogaert, G.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Craig, W.
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kiss, Mózsi Bank
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Larsson, S.
    Madejski, G.
    Bettolo, Cecilia M.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ng, J.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Tajima, H.
    Takahash, H.
    Takahashi, T.
    Tanaka, T.
    Thurston, T.
    Ueno, M.
    Varner, G.
    Yoshida, H.
    High sensitivity balloon-borne hard X-ray/soft Gamma-Ray Polarimeter PoGOLite2007In: Nuclear Science Symposium Conference Record, 2007. NSS ’07. IEEE, IEEE , 2007, Vol. 4, p. 2538-2544Conference paper (Refereed)
    Abstract [en]

    The Polarized Gamma-ray Observer - Lightweight version (PoGOLite) is a new balloon experiment capable of detecting 10% polarization from a 200 mCrab source in the 25-80 keV energy range in a single 6-hour flight for the first time. Polarization measurements of hard X-rays and soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms as well as source geometries. PoGOLite uses Compton scattering and photo-absorption to measure polarization in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators. The adoption of a well-type phoswich counter concept and a thick polyethylene neutron shield provides a narrow field-of-view (1.25 msr), a large effective area ( gt; 250 cm2 at 40-50 keV), a high modulation factor (more than 25%) and the low background ( 100 mCrab) required to conduct high-sensitivity polarization measurements. Through tests in laboratories and accelerator facilities of a scaled-down prototype with the front-end electronics of flight design and an extensive study by Monte Carlo simulation, we have demonstrated high instrument performance. PoGOLite will be ready for a first engineering flight in 2009 and a science flight in 2010, during which polarization signals from the Crab Nebula/pulsar, Cygnus X-1 and other objects will be observed.

  • 36. Moszynski, A.
    et al.
    Balcerzyk, A.
    Czarnacki, W.
    Kapusta, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Syntfeld, A.
    Szawlowski, A.
    Intrinsic energy resolution and light yield nonproportionality of BGO2004In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 51, no 3, p. 1074-1079Article in journal (Refereed)
    Abstract [en]

    The intrinsic energy resolution and nonproportionality of the light yield as a function of gamma ray energies, in the energy range of 14 keV to 1.33 MeV, were studied for small BGO (Bi4Ge3O12) crystals at room and liquid nitrogen (LN2) temperatures. The study showed that the intrinsic resolution of BGO and the light yield nonproportionality, as a function of energy do not depend on the crystal temperature. High light outputs of 14000 +/- 300 electron-hole pairs and energy resolution of 6.5% +/- 0.2% for 662 keV gamma rays were measured with the 9 mm diameter, 4 mm thick crystals, coupled to large area avalanche photodiodes and cooled down to LN2 temperature. Special attention was paid to analyzing the energy resolution of the escape peaks, which were well separated from the full-energy peaks due to the good energy resolution of BGO at LN2 temperatures and the energy of bismuth KX-rays. The intrinsic energy resolution of the BGO crystal for escape peaks does not show deviations from analysis of total energy absorption photopeaks. This is in spite of the fact that the contributions of X-rays and Auger electron cascade in creation of escape peaks are much smaller than in full-energy peaks. In the small volume crystal, mainly electrons produced in the photoelectric absorption create the escape peaks.

  • 37. Moszynski, M.
    et al.
    Balcerzyk, M.
    Czarnacki, W.
    Kapusta, M.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Schotanus, P.
    Syntfeld, A.
    Szawlowski, M.
    Study of pure NaI at room and liquid nitrogen temperatures2003In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 50, no 4, p. 767-773Article in journal (Refereed)
    Abstract [en]

    Three pure NaI crystals grown in different batches by Scionix (The Netherlands) were studied at room and liquid nitrogen temperatures. The room temperature studies performed with photomultiplier readout covered measurements of emission spectra, photoelectrons yield and energy resolution. Moreover, the scintillation light poises were measured by single photon method. Two crystals showed the photoelectron yield of about 1000 phe/MeV measured at room temperature with an XP2020Q photomultiplier. The energy resolution of the 662 keV photopeak was measured to, be about 16% and was limited mainly by a low number of photoelectrons and a large nonproportionality of the light yield. The fast light pulse had the main decay time components of 1 and 5 ns. The high initial photon intensity of the tested NaI crystals revealed a good timing. resolution of about 140 ps obtained for Co-60 gamma-rays. At. liquid nitrogen temperatures the measurements of light yield and energy resolution were performed using An Advanced Photonix, Inc. avalanche photodiode readout A high light output above 80 000 ph/MeV was measured for the best of the tested crystals. The energy resolutions of the 662 kAV photopeak of the three crystals differ a lot, varying from an excellent value of 3.8% to 6.2%. This suggests that the measured, pies energy resolutions depend on the purity of the scintillator samples reflected in the emission spectral The studies that were performed demonstrate the attractive properties of pure NaI at both room and LN2 temperature.

  • 38. Moszynski, M.
    et al.
    Balcerzyk, M.
    Czarnacki, W.
    Kapusta, M.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Schotanus, P.
    Syntfeld, A.
    Szawlowski, M.
    Kozlov, V.
    Energy resolution and non-proportionality of the light yield of pure CsI at liquid nitrogen temperatures2005In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 537, no 02-jan, p. 357-362Article in journal (Refereed)
    Abstract [en]

    The energy resolution and non-proportionality of the light yield versus gamma-ray energy of pure CsI scintillators directly coupled to Large Area Avalanche Photodiodes (LAAPDs) and cooled down to the liquid nitrogen temperatures have been studied. A very high light output above 100 000 ph/MeV was measured. One of the samples showed nearly proportional light yield response versus energy of gamma-rays yielding energy resolution of 4.3-0.2% for 662 keV gamma-rays from a (CS)-C-137 source. The intrinsic resolution of the crystals versus energy of gamma-rays has been estimated by measurements of the number of primary electron-hole pairs generated in LAAPD by scintillation light. Inspection of the gamma-ray-induced emission spectra of tested samples allows discussing different shapes of non-proportionality curves observed with various samples of CsI.

  • 39. Moszynski, M.
    et al.
    Czarnacki, W.
    Kapusta, M.
    Szawlowski, M.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Schotanus, P.
    Energy resolution and light yield non-proportionality of pure NaI scintillator studied with large area avalanche photodiodes at liquid nitrogen temperatures2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 486, no 02-jan, p. 13-17Article in journal (Refereed)
    Abstract [en]

    The pure NaI crystal has been studied using a Large Area Avalanche Photodiode (LAAPD) at near liquid nitrogen (LN2) temperatures. The study showed a high light output of 44000+/-4000 photons/MeV (ph/MeV), the energy resolution of 5.9 +/- 0.2% for 661.6 keV gamma-rays from a Cs-137 source and a good proportionality of the light yield versus gamma-ray energy. It has been shown also that a cooled LAAPD is an excellent photodetector to study scintillators at near LN2 temperatures.

  • 40. Moszynski, M.
    et al.
    Czarnacki, W.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Szawlowski, M.
    Schotanus, P.
    Kapusta, M.
    Application of large area avalanche photodiodes to study scintillators at liquid nitrogen temperatures2003In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 504, no 03-jan, p. 307-312Article in journal (Refereed)
    Abstract [en]

    Properties of Large Area Avalanche Photodiodes (LAAPDs) at liquid nitrogen (LN2) temperatures in application to study pure NaI, CsI and BGO scintillators are presented. All the tested crystals exhibited excellent performance at LN2 temperatures reflected by a high light output and very good energy resolution. The study showed that the LAAPD operating at LN2 temperatures is an excellent light readout device for testing different scintillators at low temperatures.

  • 41. Moszynski, M.
    et al.
    Czarnacki, W.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Szawlowski, M.
    Schotanus, P.
    Kapusta, M.
    Intrinsic energy resolution of pure NaI studied with large area avalanche photodiodes at liquid nitrogen temperatures2003In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 505, no 02-jan, p. 63-67Article in journal (Refereed)
    Abstract [en]

    The energy resolution and non-proportionality of the light yield vs gamma-ray energy of pure NaI scintillators directly coupled to Large Area Avalanche Photodiodes (LAAPDs) and cooled down to the liquid nitrogen temperatures have been studied. Large improvements of energy resolution and nearly proportional light yield response have been obtained at very long shaping time constants. Energy resolution of 3.8+/-0.1% for 662 keV gamma-rays from a Cs-137 source was recorded at 50 mus integration time. The intrinsic resolution of the crystal vs energy of gamma-rays has been estimated by measurements of the number of primary electron-hole pairs generated in LAAPD by scintillation light.

  • 42. Moszynski, Marek
    et al.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Wolski, Dariusz
    Czarnacki, Wieslaw
    Kapusta, Maciej
    Balcerzyk, Marcin
    Comparative study of PP0275C hybrid photodetector and XP2020Q photomultiplier in scintillation detection2006In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 1, p. P05001-Article in journal (Refereed)
    Abstract [en]

    The properties of a hybrid photodetector (HPD), type PP0275C, produced by Delft Electronic Products B.V., for scintillation detection and spectrometry were studied and compared to a standard XP2020Q photomultiplier. The study was performed for several scintillators, such as NaI(T1), CsI(T1) and LSO(Ce) of different dimensions. The excellent capability of the HPD to resolve single photoelectron events was fully confirmed. However, the study of the HPD with the scintillators showed a dramatically reduced number of photoelectrons and a further deterioration of energy resolution, depending on the size ( diameter or length) of the crystals. For a 10 mm diameter NaI(T1) a number of 5000 +/- 250 photoelectrons/MeV was measured, which corresponds to about 56% of that observed with the XP2020Q with comparable quantum efficiency. An energy resolution of 9.2% for 662 keV gamma-rays from a (137)Cs source as measured with the HPD light readout indicated on a serious degradation, larger than that arising from the statistics of photoelectrons. In conclusion, the study showed that this HPD is optimized for single photon detection but its application to scintillation detection is very limited.

  • 43.
    Nillius, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Klamra, Wlodek
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sibczynski, Pawel
    Sharma, Diksha
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Badano, Aldo
    Light output measurements and computational models of microcolumnar CsI scintillators for x-ray imaging2015In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 42, no 2, p. 600-605Article in journal (Refereed)
    Abstract [en]

    Purpose: The authors report on measurements of light output and spatial resolution of microcolumnar CsI:Tl scintillator detectors for x-ray imaging. In addition, the authors discuss the results of simulations aimed at analyzing the results of synchrotron and sealed-source exposures with respect to the contributions of light transport to the total light output. Methods: The authors measured light output from a 490-mu m CsI:Tl scintillator screen using two setups. First, the authors used a photomultiplier tube (PMT) to measure the response of the scintillator to sealed-source exposures. Second, the authors performed imaging experiments with a 27-keV monoenergetic synchrotron beam and a slit to calculate the total signal generated in terms of optical photons per keV. The results of both methods are compared to simulations obtained with hybrid MANTIS, a coupled x-ray, electron, and optical photon Monte Carlo transport package. The authors report line response (LR) and light output for a range of linear absorption coefficients and describe a model that fits at the same time the light output and the blur measurements. Comparing the experimental results with the simulations, the authors obtained an estimate of the absorption coefficient for the model that provides good agreement with the experimentally measured LR. Finally, the authors report light output simulation results and their dependence on scintillator thickness and reflectivity of the backing surface. Results: The slit images from the synchrotron were analyzed to obtain a total light output of 48 keV(-1) while measurements using the fast PMT instrument setup and sealed-sources reported a light output of 28 keV-1. The authors attribute the difference in light output estimates between the two methods to the difference in time constants between the camera and PMT measurements. Simulation structures were designed to match the light output measured with the camera while providing good agreement with the measured LR resulting in a bulk absorption coefficient of 5x10(-5) mu m(-1). Conclusions: The combination of experimental measurements for microcolumnar CsI:Tl scintillators using sealed-sources and synchrotron exposures with results obtained via simulation suggests that the time course of the emission might play a role in experimental estimates. The procedure yielded an experimentally derived linear absorption coefficient for microcolumnar Cs:Tl of 5x10(-5) mu m(-1). To the author's knowledge, this is the first time this parameter has been validated against experimental observations. The measurements also offer insight into the relative role of optical transport on the effective optical yield of the scintillator with microcolumnar structure.

  • 44. Palacz, M.
    et al.
    Fahlander, C.
    Sohler, D.
    Rudolph, D.
    Lagergren, K.
    Norlin, L. O.
    Nyberg, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Wolinska, M.
    et al,
    Investigations of neutron deficient nuclei close to Sn-100 with EUROBALL2001In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 32, no 3, p. 999-1003Article in journal (Refereed)
    Abstract [en]

    Excited states of nuclei in the vicinity of Sn-100 have been studied using: the EUROBALL detector array. Gamma-ray lines from Sn-103 have been identified for the first time, and a level scheme of low-lying excited states of Sn-103 has been established. New constraints on energies of single particle orbitals with respect to the Sn-100 core are obtained.

  • 45. Pausch, G.
    et al.
    Prade, H.
    Sobiella, M.
    Schnare, H.
    Schwengner, R.
    Kaubler, L.
    Borcan, C.
    Ortlepp, H. G.
    Oehmichen, U.
    Grawe, H.
    Schubart, R.
    Gerl, J.
    Cederkall, J.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Moszynski, M.
    Wolski, D.
    Kapusta, M.
    Axelsson, A.
    Weiszflog, M.
    Hartlein, T.
    Pansegrau, D.
    de Angelis, G.
    Ashrafi, S.
    Likar, A.
    Lipoglavsek, M.
    RoSiB - a 4 pi silicon ball for charged-particle detection in EUROBALL2000In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 443, no 03-feb, p. 304-318Article in journal (Refereed)
    Abstract [en]

    A 4 pi silicon bail for detection and identification of light charged particles in large multidetector gamma-arrays as EUROBALL is presented. The design is based on a N = 42 ball with 12 pentagons and 30 hexagons as used in the GASP array. The absorptive material for gamma-rays is minimized to the detector thickness of 300 or 500 mu m and a 0.63 mm ceramic backing. The geometrical coverage is designed for about 90% of 4 pi. A pulse shape discrimination method with totally depleted detectors working in the reverse mount allows identifying protons and alpha-particles above an energy threshold of about 2 MeV. The performances of the ball were rested at the tandem - booster accelerator combination of the MPI Heidelberg in two experiments using the high-recoil reaction of 228 MeV Ni-58 + Ti-46 and the low-recoil reaction of 95 MeV O-16 + Ni-58. The two-dimensional spectra of zero-crossing (ZC) versus energy confirmed an excellent discrimination of protons and alpha-particles in all the detectors at different angles. The energy spectra of protons and alpha-particles measured in the experiments are presented. too. The gamma-spectra measured in coincidence with various combinations of emitted particles showed a high selectivity of the ball. The reduced total efficiency for protons of 59% and 55% and alpha-particles of 44% and 32% measured in a nuclear spectroscopy application is analyzed in a Monte-Carlo simulation (GEANT). It is due to a combined influence of a thick target needed to stop the recoiling residual nuclei and thick absorbers needed to protect the Si-detectors from scattered beam. The results along with the GEANT extrapolation to optimum experimental conditions confirm that RoSiB is a highly efficient and selective device for identification of rare reaction channels with heavy ions.

  • 46.
    Pearce, Mark
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Arimoto, M.
    Axelsson, Magnus
    Stockholm University, Sweden.
    Björnsson, C. -I
    Bogaert, G.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics.
    Craig, W.
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kazejev, Jaroslav
    KTH, School of Engineering Sciences (SCI), Physics.
    Kiss, Mózsi
    KTH, School of Engineering Sciences (SCI), Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics.
    Larsson, S.
    Madejski, G.
    Marini Bettolo, C.
    Mizuno, T.
    Ng, J.
    Nomachi, M.
    Odaka, H.
    Ryde, Felix
    KTH, School of Engineering Sciences (SCI), Physics.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thurston, T.
    Ueno, M.
    Varner, G.
    Yoshida, H.
    Yuasa, T.
    PoGOLite: A balloon-borne soft gamma-ray polarimeter2007In: Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007, Universidad Nacional Autonoma de Mexico , 2007, Vol. 2, no OG PART 1, p. 479-482Conference paper (Refereed)
    Abstract [en]

    Polarized gamma-rays are expected from a wide variety of sources including rotationpowered pulsars, accreting black holes and neutron stars, and jet-dominated active galaxies. Polarization measurements provide a powerful probe of the gamma-ray emission mechanism and the distribution of magnetic and radiation fields around the source. No measurements have been performed in the soft gamma-ray band where non-thermal processes are expected to produce high degrees of polarization. The PoGOLite experiment applies well-type phoswich detector technology to polarization measurements in the 25 - 80 keV energy range. The instrument uses Compton scattering and photoabsorption in an array of 217 phoswich detector cells made of plastic and BGO scintillators, and surrounded by active BGO shields. A prototype of the flight instrument has been tested with polarized gammarays and background generated with radioactive sources. The test results and computer simulations confirm that the instrument can detect 10% polarization of a 200 mCrab source in one 6 hour balloon observation. In flight, targets are constrained to within better than 5% of the field-of-view (~5 degrees squared) in order to maximize the effective detection area during observations. The pointing direction on the sky is determined by an attitude control system comprising star trackers, differential GPS receiver system, gyroscopes, accelerometers and magnetometers which provide correction signals to a reaction wheel and torque motor system. Additionally, the entire polarimeter assembly rotates around its viewing axis to minimize systematic bias during observations. Flights are foreseen to start in 2009- 2010 and will target northern sky sources including the Crab pulsar/nebula, Cygnus X-1, and Hercules X-1. These observations will provide valuable information about the pulsar emission mechanism, the geometry around the black hole, and photon transportation in the strongly magnetized neutron star surface, respectively. Future goals include a long duration balloon flight from the Esrange facility in Northern Sweden to Canada.

  • 47. Perez, G. E.
    et al.
    Sohler, D.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Cederkall, J.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, L. O.
    Nyberg, J.
    et al,
    Structure of high-spin states in Pd-1002001In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 686, p. 41-63Article in journal (Refereed)
    Abstract [en]

    High-spin states of the neutron deficient (100)pd nucleus have been investigated via the Cr-50(Ni-58, 4p alpha) and Zn-70(S-36,6n) heavy-ion induced reactions. For the detection of evaporated particles and gamma rays the NORDBALL array equipped with ancillary detectors and the EUROGAM II detector system were utilized. By the use of in-beam spectroscopic methods 89 transitions belonging to (100)pd have been observed, 49 of which were identified for the first time. The level scheme has been extended up to E-X approximate to 16 MeV excitation energy and I approximate to 25h. The experimental results were compared with the predictions of cranked shell model calculations. Maximal spin alignments were found in the (pig(9/2))(12+)(-4) (vd(5/2),g(7/2)(3)h(11/2))(13-) and (pig(9/2)(-3)p(1/2))(11-)(vd(5/2)g(7/2)(3)h(11/2))(13-) configurations. Possible existence of octupole correlations is discussed on the basis of 6 (E 1)lB(E2) values deduced for the decays of high-spin levels in the yrast negative-parity band.

  • 48. Perot, B.
    et al.
    Carasco, C.
    Bernard, S.
    Mariani, A.
    Szabo, J. L.
    Sannie, G.
    Valkovic, V.
    Sudac, D.
    Viesti, G.
    Lunardon, M.
    Botosso, C.
    Nebbia, G.
    Pesente, S.
    Moretto, S.
    Zenoni, A.
    Donzella, A.
    Moszynski, M.
    Gierlik, M.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Le Tourneur, P.
    Lhuissier, M.
    Colonna, A.
    Tintori, C.
    Peerani, P.
    Sequeira, V.
    Salvato, M.
    Measurement of 14 MeV neutron-induced prompt gamma-ray spectra from 15 elements found in cargo containers2008In: Applied Radiation and Isotopes, ISSN 0969-8043, E-ISSN 1872-9800, Vol. 66, no 4, p. 421-434Article in journal (Refereed)
    Abstract [en]

    Within the EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) project, the gamma-ray spectra produced in a series of materials by 14-MeV tagged-neutron beams have been collected in the inspection portal equipped with large volume Nal(Tl) detectors, in order to build a database of signatures for various elements: C, N, O, Na, Al, Si, Cl, K, Ca, Cr, Fe, Ni, Cu, Zn, Pb. The measured spectra have been compared with prediction from Monte Carlo simulations to verify the consistency of the relevant nuclear data inputs. This library of measured 14-MeV neutron-induced gamma-ray spectra is currently used in a data processing algorithm to unfold the energy spectra of the transported goods into elementary contributions, thus allowing material identification.

  • 49. Perot, B.
    et al.
    Carasco, C.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Isaksson, P.
    Le Tourneur, P.
    Lhuissier, M.
    Colonna, A.
    Tintori, C.
    Peerani, P.
    Sequeira, V.
    Salvato, M.
    et al,
    Development of the EURITRACK tagged neutron inspection system2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 261, no 02-jan, p. 295-298Article in journal (Refereed)
    Abstract [en]

    The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th European Union Framework Program. It aims at developing a Tagged Neutron Inspection System (TNIS) to detect illicit materials, such as explosives and narcotics, in cargo containers. Fast neutron induced reactions produce specific gamma-rays used to determine the chemical composition of the inspected material. The associated particle technique is employed to precisely locate the interaction points of the neutrons. A new deuterium-tritium neutron generator has been developed, including a pixelized alpha particle detector. The TNIS also comprises high-efficiency fast neutron and gamma-ray detectors, a dedicated front-end electronics and an integrated software to entirely drive the system and automatically process the data. Most components have been integrated during last months at Institute Ruder Boskovic, in Zagreb, Croatia. An overview of the TNIS and of its preliminary performances is presented.

  • 50. Perot, B.
    et al.
    Perret, G.
    Mariani, A.
    Ma, J. -L
    Szabo, J. -L
    Mercier, E.
    Sannie, G.
    Viesti, G.
    Nebbia, G.
    Pesente, S.
    Lunardon, M.
    Formisano, P.
    Moretto, S.
    Fabris, D.
    Zenoni, A.
    Bonomi, G.
    Donzella, A.
    Fontana, A.
    Boghen, G.
    Valkovic, V.
    Sudac, D.
    Moszynski, M.
    Batsch, T.
    Gierlik, M.
    Wolski, D.
    Klamra, Włodzimierz
    KTH, School of Engineering Sciences (SCI), Physics.
    Isaksson, Patrick
    KTH, School of Engineering Sciences (SCI), Physics.
    Le Tourneur, P.
    Lhuissier, M.
    Colonna, A.
    Tintori, C.
    Peerani, P.
    Sequeira, V.
    Salvato, M.
    The EURITRACK project: Development of a tagged neutron inspection system for cargo containers2006In: Proc SPIE Int Soc Opt Eng, 2006Conference paper (Refereed)
    Abstract [en]

    The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Framework Program, and aims at developing a neutron inspection system for detecting threat materials (explosives, drugs, etc.) in cargo containers. Neutron interaction in the container produces specific gamma-rays used to determine the chemical composition of the inspected material. An associated particle sealed tube neutron generator is developed to allow precise location of the interaction point by direction and time-of-flight measurements of the neutrons tagged by alpha-particles. The EURITRACK project consists in developing: a transportable deuterium-tritium neutron generator including a position sensitive alpha detector (8×8 matrix of YAP:Ce crystals coupled to a multi-anode photomultiplier), fast neutron and gamma-ray detectors, front-end electronics to perform coincidence and spectroscopic measurements, and an integrated software which manages neutron generator and detectors positioning, data acquisition and analysis. Hardware components have been developed and tested by the consortium partners. Current status of this work and provisional performances of the system assessed by Monte Carlo calculations are presented.

12 1 - 50 of 74
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