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  • 1.
    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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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.

  • 2.
    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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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    KTH, Superseded Departments, Physics.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.

  • 3. Caceres, L.
    et al.
    Lepailleur, A.
    Sorlin, O.
    Stanoiu, M.
    Sohler, D.
    Dombradi, Zs.
    Bogner, S. K.
    Brown, B. A.
    Hergert, H.
    Holt, J. D.
    Schwenk, A.
    Azaiez, F.
    Bastin, B.
    Borcea, C.
    Borcea, R.
    Bourgeois, C.
    Elekes, Z.
    Fueloep, Zs.
    Grevy, S.
    Gaudefroy, L.
    Grinyer, G. F.
    Guillemaud-Mueller, D.
    Ibrahim, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S. M.
    Mrazek, J.
    Negoita, F.
    de Oliveira, F.
    Penionzhkevich, Yu. -E.
    Podolyak, Zs.
    Porquet, M. G.
    Rotaru, F.
    Roussel-Chomaz, P.
    Saint-Laurent, M. G.
    Savajols, H.
    Sletten, G.
    Thomas, J. C.
    Timar, J.
    Timis, C.
    Vajta, Zs.
    Nuclear structure studies of F-242015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 1, article id 014327Article in journal (Refereed)
    Abstract [en]

    The structure of the F-24 nucleus has been studied at GANIL using the beta decay of O-24 and the in-beam.-ray spectroscopy from the fragmentation of Na-27,Na-28, Ne-25,Ne-26, and Mg-29,Mg-30 nuclei. Combining these complementary experimental techniques, the level scheme of F-24 has been constructed up to 3.6 MeV by means of particle-gamma and particle-gamma gamma coincidence relations. Experimental results are compared to shell-model calculations using the standard USDA and USDB interactions as well as ab initio valence-space Hamiltonians calculated from the in-medium similarity renormalization group based on chiral two- and three-nucleon forces. Both methods reproduce the measured level spacings well, and this close agreement allows unidentified spins and parities to be consistently assigned.

  • 4. Claesson, T.
    et al.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Molnar, J.
    Novak, D.
    An X-ray computed tomography demonstrator using a CZT solid-state detector2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 487, no 02-jan, p. 202-208Article in journal (Refereed)
    Abstract [en]

    A demonstrator of Computed Tomography (CT) has been designed and built for educational purposes. The system is based on a solid-state CdZnTe detector and a standard PC. The mechanics of the system is controlled and data is acquired by programs written in LabVIEW. CT images are reconstructed using MATLAB programs.

  • 5. Dénes, E.
    et al.
    Fenyvesi, A.
    Futó, E.
    Kerék, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kiss, T.
    Molnár, J.
    Novák, D.
    Soós, C.
    Tölyhi, T.
    VandeVyvre, P.
    Radiation tolerance qualification tests of the final source interface unit for the ALICE experiment for the ALICE collaboration2007In: Proceedings - 12th Workshop on Electronics for LHC and Future Experiments, LECC 2006, CERN , 2007, p. 438-441Conference paper (Refereed)
    Abstract [en]

    The ALICE Detector Data Link (DDL) is a high-speed optical link designed to interface the readout electronics of ALICE sub-detectors to the DAQ computers. The Source Interface Unit (SIU) of the DDL will operate in radiation environment. Previous tests showed that a configuration loss of SRAM-based FPGA devices may happen and the frequency of undetected data errors in the FPGA user memory area is also not acceptable. Therefore, we redesigned the SIU card using another FPGA based on flash technology. In order to detect bit errors in the user memory we added parity check logic to the design. The new SIU has been extensively tested using neutron and proton irradiation to verify its radiation tolerance. In this paper we summarize the design changes, introduce the final design, and the results of the radiation tolerance measurements on the final card.

  • 6. Dénes, E.
    et al.
    Fenyvesi, A.
    Hirn, A.
    Kerék, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kiss, T.
    Molnár, J.
    Novák, D.
    Soós, C.
    Tölyhi, T.
    Vyvre, P. V.
    Radiation tolerant source interface unit for the ALICE experiment2005In: Proceedings - 11th Workshop on Electronics for LHC and Future Experiments, LECC 2005, CERN , 2005, p. 291-293Conference paper (Refereed)
    Abstract [en]

    The ALICE Detector Data Link (DDL) is a high-speed optical link designed to interface the readout electronics of ALICE sub-detectors to the DAQ computers. The Source Interface Unit (SIU) of the DDL will operate in radiation environment. Tests showed that configuration loss of the Altera APEX II FPGA device used earlier on the DDL SIU card is only marginally acceptable. We developed a new version of the SIU card using Actel ProASIC+ device based on flash memory technology. The new SIU card has been extensively tested using neutron and proton irradiation. In this paper we present the SIU card and describe the results of irradiation measurements.

  • 7. Emri, M.
    et al.
    Opposits, G.
    Kis, S. A.
    Trón, L.
    Veres, P.
    Pányik, Á.
    Valastyán, I.
    Imrek, J.
    Moinar, J.
    Novák, D.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Balkay, L.
    Software development framework supporting multimodal tomographic imaging2007In: 2006 IEEE Nuclear Science Symposium Conference Record, IEEE , 2007, p. 1857-1859Conference paper (Refereed)
    Abstract [en]

    Engineers specialized in multimodal tomography regularly face a wide scale of programming tasks requiring an integrated software system to ensure cost efficiency. Accordingly, a software development framework has been worked out comprising libraries for cluster-based data acquisition, image reconstruction, management of data files and complex multimodal volumetric visualization. This framework enabled us to develop complex software for our miniPET project [1]. This software contains a graphical application integrating data acquisition, cluster monitoring, event sorting, image reconstruction, interactive image processing tools for advanced multimodal visualization. It also contains utilities to solve these tasks without graphical user interface. The components of our acquisition program can run on embedded Linux systems making new ways to develop any other types of data acquisition software that uses embedded Linux systems. A versatile development framework is developed containing specific libraries and special file formats that support multimodal tomography. This framework was successfully used to elaborate our complex miniPET software.

  • 8. Franchoo, S.
    et al.
    Achouri, N. L.
    Algora, A.
    Al-Khatib, A.
    Angelique, J. C.
    Azaiez, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Yamamoto, A.
    et al.,
    RECENT RESULTS FROM GANIL2009In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 40, no 3, p. 419-425Article in journal (Refereed)
    Abstract [en]

    The shell structure of the nucleus implies the existence of magic numbers. Since several years many indications have been accumulated, theoretically as well as through experiments at various laboratories around the world, that if one moves away from stability, the location of the magic numbers shifts as an inescapable consequence of the evolving nature of the nuclear force itself. In this respect, it is the balance between the tensor and spin-orbit components that seems particularly instrumental. Illustrative examples from recent experiments at Ganil, at the neutron-rich and proton-rich side of the nuclear chart for N or Z equal 20 or 28, will be presented here.

  • 9. Hegyesi, G.
    et al.
    Imrek, J.
    Kalinka, G.
    Molnar, J.
    Novak, D.
    Vegh, J.
    Balkay, L.
    Emri, M.
    Kis, S. A.
    Molnar, G.
    Tron, L.
    Valastyan, I.
    Bagamery, I.
    Bukki, T.
    Rozsa, S.
    Szabo, Z.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ethernet based distributed data acquisition system for a small animal PET2006In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, no 4, p. 2112-2117Article in journal (Refereed)
    Abstract [en]

    We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8 x 8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer including a digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system and coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and generates a time stamp with a coincidence resolution of less than 2 us. The data acquisition system is based on Ethernet network and is highly scalable in size and performance.

  • 10. Hegyesi, G.
    et al.
    Imrek, J.
    Kalinka, G.
    Molnár, J.
    Novák, D.
    Végh, J.
    Balkay, L.
    Emri, M.
    Molnár, G.
    Trón, L.
    Bagaméry, I.
    Bükki, T.
    Rózsa, S.
    Szabó, Z.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Development of an FPGA-based data acquisition module for small animal PET2004In: 2004 IEEE Nuclear Science Symposium Conference Record, 2004, p. 2957-2961Conference paper (Refereed)
    Abstract [en]

    We report on the design of a DAQ module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is built up from strictly identical DAQ modules, and which has no built-in hardware limitation on the maximum number of modules. The developed DAQ module comprises of an LSO scintillator crystal block, a position sensitive PMT, analog signal conditioning circuits, a digitizer, an FPGA for digital signal processing and a communication module through which the collected data is sent to a cluster of computers for post processing and storage. Instead of implementing hardware coincidence detection between the modules we attach a precise time-stamp to each event in our design, and the coincidence is determined by the data collecting computers during the post processing. The digital CFD algorithm implemented in the FPGA gives a time resolution of 2 to 3 ns FWHM for real detector signals.

  • 11.
    Hegysei, G.
    et al.
    Institute of Nuclear Research of the Hungarian Academy of Sciences.
    Imrek, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences.
    Valastyán, Iván
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ethernet based distributed data acquistion system for small animal PET2006In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, no 4Article in journal (Refereed)
    Abstract [en]

    We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8times8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer and digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system, coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and it generates a time stamp with a coincidence resolution of 2 to 3 ns. The data acquisition System is based on Ethernet network and is highly scalable in size and performance

  • 12. Imrek, J.
    et al.
    Hegyesi, Gy.
    Kalinka, G.
    Moinar, J.
    Novák, D.
    Valastyán, I.
    Balkay, L.
    Emri, M.
    Opposits, G.
    Kis, S. A.
    Trón, L.
    Bükki, T.
    Szabó, Zs.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Internals and evaluation of the miniPET-II detector module2007In: 2007 IEEE Nuclear Science Symposium Conference Record, 2007, p. 2930-2932Conference paper (Refereed)
    Abstract [en]

    We report on the architecture of the System-on-Module (SoM) developed by our group for miniPET-II, the second version of our small animal PET scanner. The paper describes the hardware and software implementation details of the SoM we realized inside the miniPET-II detector module, the embedded Linux operation system, and the the initial results of bandwidth test measurements on the assembled SoM. Detailed description is given on the interfacing of the updated miniPET IP Core to the SoM, on the efficient data transfer method that implements device-to-device DMA transfer, and on the usage of User Datagram Protocol (UDP/IP) for high speed data transfer.

  • 13. Imrek, J.
    et al.
    Hegyesi, Gy.
    Kalinka, G.
    Molnár, J.
    Novák, D.
    Valastyán, I.
    Végh, J.
    Balkay, L.
    Emri, M.
    Kis, S.
    Trón, L.
    Bükki, T.
    Szabó, Zs.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Development of an improved detector module for miniPET-II2007In: 2006 IEEE Nuclear Science Symposium Conference Record, IEEE , 2007, p. 3037-3040Conference paper (Refereed)
    Abstract [en]

    We present a new detector module developed for miniPET-II, the second generation of the miniPET small animal PET scanners. The improved module features new hardware components for better performance: LySO crystal material, increased number of crystal segments, Hamamatsu H9500 PSPMT, Xilinx Virtex-4 FPGA and Gigabit Ethernet. However, the principle of operation is the same: no hardware coincidence detection is implemented, data is acquired in list mode and transfered over an Ethernet network. The resulting new module is more suitable for full ring configurations.

  • 14. Kis, S. A.
    et al.
    Emri, M.
    Opposits, G.
    Bukki, T.
    Valastyan, I.
    Hegyesi, Gy
    Imrek, J.
    Kalinka, G.
    Molnar, J.
    Novak, D.
    Vegh, J.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Tron, L.
    Balkay, L.
    Comparison of Monte Carlo simulated and measured performance parameters of miniPET scanner2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 571, no 02-jan, p. 449-452Article in journal (Refereed)
    Abstract [en]

    In vivo imaging of small laboratory animals is a valuable tool in the development of new drugs. For this purpose, miniPET, an easy to scale modular small animal PET camera has been developed at our institutes. The system has four modules, which makes it possible to rotate the whole detector system around the axis of the field of view. Data collection and image reconstruction are performed using a data acquisition (DAQ) module with Ethernet communication facility and a computer cluster of commercial PCs. Performance tests were carried out to deter-mine system parameters, such as energy resolution, sensitivity and noise equivalent count rate. A modified GEANT4-based GATE Monte Carlo software package was used to simulate PET data analogous to those of the performance measurements. GATE was run on a Linux cluster of 10 processors (64 bit, Xeon with 3.0 GHz) and controlled by a SUN grid engine. The application of this special computer cluster reduced the time necessary for the simulations by an order of magnitude. The simulated energy spectra, maximum rate of true coincidences and sensitivity of the camera were in good agreement with the measured parameters.

  • 15. Kis, S. A.
    et al.
    Valastyán, I.
    Hegyesi, Gy.
    Imrek, J.
    Kalinka, G.
    Molnár, J.
    Novák, D.
    Végh, J.
    Balkay, L.
    Emri, M.
    Molnár, G.
    Bagaméry, I.
    Bükki, T.
    Rózsa, S.
    Szabó, Zs.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Trón, L.
    Performance Characteristics of a miniPET Scanner Dedicated to Small Animal Imaging2005In: 2005 IEEE Nuclear Science Symposium Conference Record, 2005, p. 1645-1648Conference paper (Refereed)
    Abstract [en]

    An easy to scale up modular PET scanner was developed for imaging small animals. Energy resolution, spatial resolution and count rate performance were determined as system parameters. The configuration provided an average energy resolution of 19.6 % and the image resolution ranges was 1.5 to 2.3 mm in radial direction. The sensitivity of the miniPET was 1.08 cps/kBq as determined using a point source. In addition, results of rat brain scan performed with FDG are given to characterize imaging capability of the system. The displayed data document that the miniPET scanner supports good quality brain imaging of small animals.

  • 16.
    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.

  • 17.
    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.

  • 18. Novák, D.
    et al.
    Granholm, L.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Milito, G.
    Molnár, J.
    Norlin, Lars-Olov
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Rathsman, P.
    Székely, G.
    In flight SEU tests on the European SMART-1 spacecraft2005In: Proceedings of the European Conference on Radiation and its Effects on Components and Systems, RADECS, 2005, p. PH11-PH13Conference paper (Refereed)
    Abstract [en]

    The SMART-I satellite launched by the European Space Agency has traveled to an orbit around the Moon driven by its own ion engine. Because of the characteristics of the ion engine mission required many revolutions to reach the Moon and the time to pass through the radiation belts around the Earth was significant. The spacecraft is exposed to solar protons throughout its mission. In advance the flight in-beam test data was collected to asses the radiation hardness properties of an SRAM, one of the components of the system unit of the satellite. Single Event Upset data is available for this component and Solar Proton Flux was measured by the GOES satellite in Geosynchronous orbit. The aim of this work is to compare the predictions of the in-beam tests and the effects of the in space irradiation of SRAM circuits on board.

  • 19. Novák, D.
    et al.
    Granholm, L.
    Kerek, Andras
    KTH.
    Molnár, J.
    Norlin, Lars-Olov
    KTH, School of Engineering Sciences (SCI), Physics.
    Sipos, A.
    Szabó, B.
    Component tests for the PRISMA spacecraft2007In: RADECS 2007: Proceedings of the 9th European Conference on Radiation and Its Effects on Components and Systems, IEEE , 2007, p. 595-598Conference paper (Refereed)
    Abstract [en]

    TID and proton tests are reported on some COTS components for the PRISMA satellite project. TID test level was more than 20 krad and 170 MeV protons were used for the single event tests.

  • 20. Palacz, M
    et al.
    Seweryniak, D
    Atac, A
    Blomqvist, J
    CEDERWALL, BO
    KTH, Superseded Departments, Physics.
    Fahlander, C
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andreas
    KTH, Superseded Departments, Physics.
    Kownacki, J
    Norlin, L O
    Nyberg, J
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Ideguchi, E
    Julin, R
    Juutinen, S
    Mitarai, S
    Piiparinen, M
    Sletten, G
    Tormanen, S
    Virtanen, A
    In-beam gamma-ray spectroscopy of Co-561997In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 627, no 1, p. 162-174Article in journal (Refereed)
    Abstract [en]

    Excited states of Co-56 were studied in the reaction Al-27(S-32,2p1n) Co-56. The NORDBALL array with a Neutron Wall and a Silicon Ball was employed. The excited states were interpreted in terms of particle-hole excitations with respect to the doubly magic N = Z = 28 core.

  • 21. 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.

  • 22. Ruchowska, E.
    et al.
    Plociennik, W. A.
    Zylicz, A.
    Mach, H.
    Kvasil, J.
    Algora, A.
    Amzal, N.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Borge, M. G.
    Boutami, R.
    Butler, P. A.
    Cederkäll, J.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Fogelberg, B.
    Fraile, L. M.
    Fynbo, H. O. U.
    Hagebo, E.
    Hoff, P.
    Gausemel, H.
    Jungclaus, A.
    Kaczarowski, R.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kurcewicz, W.
    Lagergren, K.
    KTH, School of Engineering Sciences (SCI), Physics.
    Nacher, E.
    Rubio, B.
    Syntfeld, A.
    Tengblad, O.
    Wasilewski, A. A.
    Weissman, L.
    Nuclear structure of Th-2292006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 4Article in journal (Refereed)
    Abstract [en]

    Lifetimes of excited states in Th-229, populated in the beta decay of Ac-229, have been measured using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new gamma lines have been introduced into the beta-decay scheme of Ac-229 based on results of gamma gamma coincidence measurements. Reduced transition probabilities have been determined for more than 70 gamma transitions in Th-229. Average parallel to D-0 parallel to values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest K-pi=1/2(+/-),3/2(+/-), and 5/2(+/-) parity partner bands, respectively. Excited states in Th-229 and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2(+) isomeric state is predicted to be about 10 h. Potential energy surfaces on the (beta(2),beta(3)) plane for the lowest single quasiparticle configurations in Th-229 have been calculated using the Strutinsky method.

  • 23. Sanchez-Crespo, A.
    et al.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Molnar, J.
    Norlin, Lars Olov
    KTH, Superseded Departments, Physics.
    Skatt, B.
    Grusell, E.
    Novak, D.
    Sipos, A.
    Van der Marel, J.
    Vegh, J.
    Proton therapy beam dosimetry with silicon CMOS image sensors2004In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 525, no 02-jan, p. 289-293Article in journal (Refereed)
    Abstract [en]

    A 16 mm(2) CMOS Image Sensor with more than 100 000 pixels and with a standard video output was irradiated with 48, 95 and 180 MeV protons. Proton-induced nuclear reactions in silicon were detected as bright spots or tracks in the images. The angular and energy-dependent response of the detector were studied. The application to proton dosimetry is discussed.

  • 24. Simon, A.
    et al.
    Balkay, L.
    Kalinka, G.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Novak, D.
    Sipos, A.
    Vegh, J.
    Tron, L.
    Molnar, J.
    High spatial resolution measurement of depth-of-interaction of a PET LSO crystal2005In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 546, no 1-2, p. 33-36Article in journal (Refereed)
    Abstract [en]

    A new type of experimental technique to investigate the depth- of-interaction (DOI) dependence in small scintillator elements designed for high-resolution animal PET is tested. An Oxford-type nuclear microprobe was used to irradiate a lutetium oxyorthosilicate (LSO) crystal (2 x 2 x 10 mm) with a highly focused, (few micrometers diam.), 2 MeV He+ beam. Pulse height spectra from a PMT attached to one end of the LSO crystal were collected in list mode. By scanning the beam over the crystal high-resolution 2D-images are generated and thus the DOI effect in the scintillator could be investigated. The obtained results of the overall DOI dependence confirm previous findings using gamma-rays. Since the present experimental setup allows obtaining data with several orders of magnitude better spatial resolution than with collimated gamma-beam, the method can be applied for variety of problems where high spatial resolution is required.

  • 25. Sipos, A.
    et al.
    Grusell, E.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Molnar, J.
    Norlin, L. O.
    Novak, D.
    Sanchez-Crespo, A.
    Van der Marel, J.
    Vegh, J.
    Visualization of neutron and proton induced particle production in a CMOS image sensor2003In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 509, no 03-jan, p. 328-332Article in journal (Refereed)
    Abstract [en]

    A commercially available off the shelf CMOS Image Sensor was irradiated with neutron and proton beams. The Image Sensor is equipped with standard video output. The data were collected on VHS videotapes and analyzed off-line after digitization. The camera chip with 110 000 pixels each having 12 x 12 mum(2) size, shows the nuclear reactions occurring in the sensitive layer as bright spots or tracks. Several applications are suggested based on the inexpensive CMOS Image Sensor.

  • 26. Slunga, E.
    et al.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Ideguchi, E.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    van der Marel, J.
    Novak, D.
    Norlin, L. O.
    Scintillation response of BaF2 and YAlO3: Ce (YAP : Ce) to energetic ions2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 469, no 1, p. 70-76Article in journal (Refereed)
    Abstract [en]

    The scintillation response of BaF2 and YAP: Ce to protons. a particles, O-16 and Si-28 ions in the 5-30 MeV range has been investigated. The ratio between the fast and slow parts of the scintillator signal for BaF2 has been used to separate protons, a particles and heavier ions, and the dependence of this ratio on the particle energy has been studied. The time constants and intensities of the two components of the YAP: Ce signal were measured, as were the time constant and intensity of the weak component of the slow part of the BaF2 signal. Furthermore, the dependence of the light yield on the particle energy has been investigated for both BaF2 and YAP: Ce.

  • 27. Sohler, D.
    et al.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Ataç, Ayşe
    Department of Physics, Ankara University, 06100 Tandogan, Ankara, Turkey.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, Lars Olov
    KTH, Superseded Departments, Physics.
    Weiszflog, M.
    et, al
    Band-terminating states in Ag-1012004In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 733, no 02-jan, p. 37-52Article in journal (Refereed)
    Abstract [en]

    Excited states of the neutron deficient Ag-101 nucleus have been investigated via the Cr-50(Ni-58, 3rho1alpha) heavy-ion induced reaction at 261 meV by use of in-beam spectroscopic methods. On the basis of the measured gammagamma-cincidence relations and angular distribution ratios high-spin bands have been extended up to I-pi = 35/2(+), 45/2((-)) and (49/2(-)). The negative parity states at the highest energy have been interpreted as terminating non-collective oblate states in the framework of the Nilsson-Strutinsky cranking formalism.

  • 28. Stanoiu, M.
    et al.
    Azaiez, F.
    Becker, F.
    Belleguic, M.
    Borcea, C.
    Bourgeois, C.
    Brown, B. A.
    Dlouhy, Z.
    Dombradi, Z.
    Fulop, Z.
    Grawe, H.
    Grevy, S.
    Ibrahim, F.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S.
    van der Marel, Hans
    KTH, Superseded Departments, Physics.
    Mayet, P.
    Mrazek, J.
    Mandal, S.
    Guillemaud-Mueller, D.
    Negoita, F.
    Penionzhkevich, Y. E.
    Podolyak, Z.
    Roussel-Chomaz, P.
    Saint Laurent, M. G.
    Savajols, H.
    Sorlin, O.
    Sletten, G.
    Sohler, D.
    Timar, J.
    Timis, C.
    Yamamoto, A.
    Study of drip line nuclei through two-step fragmentation2004In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 20, no 1, p. 95-96Article in journal (Refereed)
    Abstract [en]

    We have studied the structure of light neutron-rich nuclei around N = 16 by employing the in-beam gamma-ray spectroscopy technique using the fragmentation of secondary beams of Ne-25,Ne-26, Na-27,Na-28 and Mg-29,Mg-30 isotopes. This secondary-beam cocktail was obtained by the fragmentation of a 36 S beam at 77.5 MeV.A by the SISSI/GANIL facility. By a second-step fragmentation, we have measured gamma-ray-residue coincidences in C17-20 and O-23,O-24 and described the obtained levels in the framework of the shell model.

  • 29. Stanoiu, M.
    et al.
    Azaiez, F.
    Dombradi, Z.
    Sorlin, O.
    Brown, B. A.
    Belleguic, M.
    Sohler, D.
    Saint Laurent, M. G.
    Penionzhkevich, Y. E.
    Sletten, G.
    Borcea, C.
    Bourgeois, C.
    Bracco, A.
    Daugas, J. M.
    Dlouhy, Z.
    Donzaud, C.
    Fulop, Z.
    Guillemaud-Mueller, D.
    Grevy, S.
    Ibrahim, F.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S.
    Mayet, P.
    Mandal, S.
    Mittig, W.
    Mrazek, J.
    Negoita, F.
    De Oliveira-Santos, F.
    Podolyak, Z.
    Pougheon, F.
    Roussel-Chomaz, P.
    Savajols, H.
    Sobolev, Y.
    Stodel, C.
    Timar, J.
    Yamamoto, A.
    Study of neutron rich carbon and oxygen nuclei up to drip line2004In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 746, p. 135C-139CArticle in journal (Refereed)
    Abstract [en]

    In-beam gamma-spectroscopy using fragmentation reactions of radioactive beams have been performed in order to study the structure of excited states in neutron rich oxygen and carbon isotopes. For the produced fragments, gamma-ray energies, intensities and gamma-gamma coincidences have been measured. The experiment was performed at GANIL. New gamma-lines have been identified and placed in level schemes for C17-20. The non observation of any gamma-ray in O-23,O-24 suggests that their first excited states lie above the neutron threshold. These results are discussed in the framework of shell model calculations.

  • 30. Stanoiu, M.
    et al.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Van Der Marel, Hans
    KTH, School of Engineering Sciences (SCI), Physics.
    Yamamoto, A.
    et.,
    N=14 and 16 shell gaps in neutron-rich oxygen isotopes2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 3Article in journal (Refereed)
    Abstract [en]

    In-beam gamma-ray spectroscopy using fragmentation reactions of both stable and radioactive beams has been performed in order to study the structure of excited states in neutron-rich oxygen isotopes with masses ranging from A=20 to 24. For the produced fragments, gamma-ray energies, intensities, and gamma-gamma coincidences have been measured. Based on this information new level schemes are proposed for O-21,O-22 up to the neutron separation energy. The nonobservation of any gamma-decay branch from O-23 and O-24 suggests that their excited states lie above the neutron decay thresholds. From this, as well as from the level schemes proposed for O-21 and O-22, the size of the N=14 and 16 shell gaps in oxygen isotopes is discussed in the light of shell-model calculations.

  • 31. Stanoiu, M.
    et al.
    Sohler, D.
    Sorlin, O.
    Azaiez, F.
    Dombradi, Z.
    Brown, B. A.
    Belleguic, M.
    Borcea, C.
    Bourgeois, C.
    Dlouhy, Z.
    Elekes, Z.
    Fulop, Z.
    Grevy, S.
    Guillemaud-Mueller, D.
    Ibrahim, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S. M.
    Mandal, S.
    Mrazek, J.
    Negoita, F.
    Penionzhkevich, Y. E.
    Podolyak, Z.
    Roussel-Chomaz, P.
    Saint-Laurent, M. G.
    Savajols, H.
    Sletten, G.
    Timar, J.
    Timis, C.
    Yamamoto, A.
    Disappearance of the N=14 shell gap in the carbon isotopic chain2008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, no 3Article in journal (Refereed)
    Abstract [en]

    The structure of C-17-20(6) nuclei was investigated by means of the in-beam gamma-ray spectroscopy technique using fragmentation reactions of radioactive beams. Based on particle-gamma and particle-gamma gamma coincidence data, level schemes are constructed for the neutron-rich C17-20 nuclei. The systematics of the first excited 2(+) states in the carbon isotopes is extended for the first time to A = 20 showing that in contrast to the case of the oxygen isotopes, the N = 14 subshell closure disappears. Experimental results are compared with shell-model calculations. Agreement between them is found only if a reduced neutron-neutron effective interaction is used. Implications of this reduced interaction in some properties of weakly bound neutron-rich Carbon are discussed.

  • 32. Stanoiu, M.
    et al.
    Sohler, D.
    Sorlin, O.
    Dombradi, Zs.
    Azaiez, F.
    Brown, B. A.
    Borcea, C.
    Bourgeois, C.
    Elekes, Z.
    Fueloep, Zs.
    Grevy, S.
    Guillemaud-Mueller, D.
    Ibrahim, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S. M.
    Mrazek, J.
    Negoita, F.
    Penionzhkevich, Yu. -E.
    Podolyak, Zs.
    Porquet, M. G.
    Roussel-Chomaz, P.
    Saint-Laurent, M. G.
    Savajols, H.
    Sletten, G.
    Timar, J.
    Timis, C.
    Spectroscopy of (26)F2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 85, no 1, p. 017303-Article in journal (Refereed)
    Abstract [en]

    The structure of the weakly bound (26)(9)F(17) odd-odd nucleus, produced from (27,28)Na nuclei, has been investigated at GANIL by means of the in-beam gamma-ray spectroscopy technique. A single gamma-line is observed at 657(7) keV in (26)(9)F which has been ascribed to the decay of the excited J = 2(+) state to the J = 1(+) ground state. The possible presence of intruder negative parity states in (26)F is also discussed.

  • 33. Vajta, Zs.
    et al.
    Stanoiu, M.
    Sohler, D.
    Jansen, G. R.
    Azaiez, F.
    Dombradi, Zs.
    Sorlin, O.
    Brown, B. A.
    Belleguic, M.
    Borcea, C.
    Bourgeois, C.
    Dlouhy, Z.
    Elekes, Z.
    Fueloep, Zs.
    Grevy, S.
    Guillemaud-Mueller, D.
    Hagen, G.
    Hjorth-Jensen, M.
    Ibrahim, F.
    Kerek, Andras
    KTH, School of Engineering Sciences (SCI), Physics.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S. M.
    Mandal, S.
    Mayet, P.
    Mrazek, J.
    Negoita, F.
    Penionzhkevich, Yu. -E.
    Podolyak, Zs.
    Roussel-Chomaz, P.
    Saint-Laurent, M. G.
    Savajols, H.
    Sletten, G.
    Timar, J.
    Timis, C.
    Yamamoto, A.
    Excited states in the neutron-rich nucleus F-252014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 5, p. 054323-Article in journal (Refereed)
    Abstract [en]

    The structure of the nucleus F-25(9) was investigated through in-beam. gamma-ray spectroscopy of the fragmentation of Ne-26 and Na-27,Na-28 ion beams. Based on the particle-gamma and particle-gamma gamma coincidence data, a level scheme was constructed and compared with shell model and coupled-cluster calculations. Some of the observed states were interpreted as quasi-single-particle states built on top of the closed-shell nucleus O-24, while the others were described as states arising from coupling of a single proton to the 2(broken vertical bar) core excitation of O-24.

  • 34.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bone, D.
    Brodin, L.-A.
    Elmqvist, H.
    Lagerlöf, J.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Molnar, J.
    Novak, D.
    Validation of an iterative reconstruction for a mobile tomographic gamma camera system - The Cardiotom2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 580, no 2, p. 1097-1100Article in journal (Refereed)
    Abstract [en]

    The Cardiotom is a mobile gamma camera that uses ectomography, an alternative method of acquisition to SPECT. It is designed for early diagnosis of myocardial and cerebral infarctions in the emergency room. Ectomography is a limited view angle method, using a rotating slant hole collimator and a stationary camera head, to acquire projection images. The aim of this work was to validate a fully 3D ML-EM iterative reconstruction algorithm for the Cardiotom. Validation measurements were performed with Tc-99m point sources. Resolution in the reconstructed volume was determined in X, Y. and Z directions from the point spread functions. The results were compared with the values for the formerly used filtered back projection (FBP). The new reconstruction algorithm provides greatly improved depth resolution with respect to the FBP method previously implemented on the Cardiotom. Furthermore, for clinical examinations, images can be available for interpretation within 15 min of the injection, therefore, valuable information can be obtained without delaying treatment of the patient. (c) 2007 Elsevier B.V. All rights reserved.

  • 35.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bonec, D.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Molnár, J.
    Novák, D.
    Unified software platform for nuclear medical image representation visualization and reconstructionIn: Journal of InstrumentsArticle in journal (Other academic)
  • 36.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Elmqvist, Håkan
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Molnar, J.
    Novak, D.
    Ribbe, T.
    Gated tomographic imaging in ectomography using a dynamic heart phantom2007In: Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE, IEEE , 2007, p. 3414-3417Conference paper (Refereed)
    Abstract [en]

    A new computer controlled dynamic heart phantom and the connection of an ECG unit to a tomographic gamma camera system, developed for ectomographic imaging, is presented. The phantom is used for validation of the camera. Measurements were performed to test the phantom as well as to study the feasibility of gated imaging in ectomography. The camera is intended for early diagnosis of myocardial and cerebral infarctions.

  • 37.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Imrek, J.
    Hegyesi, G.
    Molnar, J.
    Novak, D.
    Bone, D.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Data acquisition and image reconstruction systems from the MiniPET scanners to the CARDIOTOM camera2007In: Nuclear Physics Methods And Accelerators In Biology And Medicine / [ed] Granja, C; Leroy, C; Stekl, I, American Institute of Physics (AIP), 2007, Vol. 958, p. 282-283Chapter in book (Refereed)
    Abstract [en]

    Nuclear imaging devices play an important role in medical diagnosis as well as drug research. The first and second generation data acquisition systems and the image reconstruction library developed provide a unified hardware and software platform for the miniPET-I, miniPET-II small animal PET scanners and for the CARDIOTOM(TM).

  • 38.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Imrek, J.
    Hegyesi, Gy.
    Kalinka, G.
    Molnar, J.
    Novak, D.
    Sipos, A.
    Bagamery, I.
    Balkay, L.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Experimental scanner setup from miniPET II detector module2009In: 2008 IEEE Nuclear Science SYmposium Conference Record, 2009, p. 3121-3124Chapter in book (Other academic)
    Abstract [en]

    The PET technique is widely used in human clinical studies and recent developments of image resolution has made it suitable for small animal research. The second generation of our PET scanner consists of 12 detector modules and has a field of view large enough to image mice and rats. Parameters of the incoming data are extracted by Digital Signal Processing in the detector modules and a System-on-Module is used to transmit the data through an Ethernet network for storage and reconstruction. The experimental scanner setup described in this paper was constructed in order to investigate the applicability of the developed detector modules in a full ring small animal PET camera. The preliminary results of the system are also presented.

  • 39.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Imrek, J.
    Molnár, J.
    Novák, D.
    Balkay, L.
    Emri, M.
    Trón, L.
    Bükki, T.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 571, no 1-2, p. 219-222Article in journal (Refereed)
    Abstract [en]

    Iterative reconstruction methods are commonly used to obtain images with high resolution and good signal-to-noise ratio in nuclear imaging. The aim of this work was to develop a scalable, fast, cluster based, fully 3-D iterative image reconstruction package for our small animal PET camera, the miniPET. The reconstruction package is developed to determine the 3-D radioactivity distribution from list mode type of data sets and it can also simulate noise-free projections of digital phantoms. We separated the system matrix generation and the fully 3-D iterative reconstruction process. As the detector geometry is fixed for a given camera, the system matrix describing this geometry is calculated only once and used for every image reconstruction, making the process much faster. The Poisson and the random noise sensitivity of the ML-EM iterative algorithm were studied for our small animal PET system with the help of the simulation and reconstruction tool. The reconstruction tool has also been tested with data collected by the miniPET from a line and a cylinder shaped phantom and also a rat.

  • 40.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Imrek, J.
    Hegyesi, G.
    Kalinka, G.
    Molnar, J.
    Novak, D.
    LSO based dual slice helical CT and PET demonstrators2011In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 633, p. S300-S302Article in journal (Refereed)
    Abstract [en]

    Two demonstrators, a spiralCT and a miniPET, have been designed and constructed for educational purposes. Computed tomographs (CTs) and positron emission tomographs (PETs) are some of the most commonly used structural and functional imaging devices in medicine, respectively. There is a need for transparent demonstrators where the principles of the different modalities and their functions are presented. The aim of the developments of these systems was to present the major building blocks of CT and PET for undergraduate students. Photon detection in both systems is based on small pixelised scintillation crystals with position sensitive PMT readout. Similar analogue and digital data processing based on FPGA technique is applied for the demonstrators and common image reconstruction and presentation software components are used.

  • 41.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Molnar, J.
    Novak, D.
    Vegh, J.
    Emri, M.
    Tron, L.
    A SPECT demonstrator - revival of a gamma camera2006In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 563, no 1, p. 274-277Article in journal (Refereed)
    Abstract [en]

    A gamma camera has been updated and converted to serve as a demonstrator for educational purposes. The gantry and the camera head were the only part of the system that remained untouched. The main reason for this modernization was to increase the transparency of the gamma camera by partitioning the different logical building blocks of the system and thus providing access for inspection and improvements throughout the chain. New data acquisition and reconstruction software has been installed. By taking these measures, the camera is now used in education and also serves as a platform for tests of new hardware and software solutions. The camera is also used to demonstrate 3D (SPECT) imaging by collecting 2D projections from a rotatable cylindrical phantom. Since the camera head is not attached mechanically to the phantom, the effect of misalignment between the head and the rotation axis of the phantom can be studied. (c) 2006 Elsevier B.V. All rights reserved.

  • 42. Vegh, J.
    et al.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Molnar, J.
    Norlin, Lars Olov
    KTH, School of Engineering Sciences (SCI), Physics.
    Novak, D.
    Sanchez-Crespo, A.
    Van der Marel, J.
    Fenyvesi, A.
    Valastyan, I.
    Sipos, A.
    Visualization of heavy ion-induced charge production in a CMOS image sensor2004In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 525, no 02-jan, p. 229-235Article in journal (Refereed)
    Abstract [en]

    A commercial CMOS image sensor was irradiated with heavy ion beams in the several MeV energy range. The image sensor is equipped with a standard video output. The data were collected on-line through frame grabbing and analysed off-line after digitisation. It was shown that the response of the image sensor to the heavy ion bombardment varied with the type and energy of the projectiles. The sensor will be used for the CMS Barrel Muon Alignment system.

  • 43. Westman, S.
    et al.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, L. O.
    Novak, D.
    Heavy ion detection at extreme high vacuum by means of a YAP: Ce scintillator2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 481, no 1-3, p. 655-660Article in journal (Refereed)
    Abstract [en]

    A device for the detection of highly charged heavy ions in the CRYRING accelerator is presented. The system consists of a YAP: Ce scintillator, including a set of reflectors and lenses for the transmission of the scintillation light to the PM-tube. The performance of the system has been tested in measurements with electron cooled heavy ion beams.

1 - 43 of 43
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