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Spectroscopy of neutron deficient nuclei in the A=90 and A=170 mass regions
KTH, Superseded Departments, Physics.ORCID iD: 0000-0003-1996-0805
2002 (English)Doctoral thesis, comprehensive summary (Other scientific)
Place, publisher, year, edition, pages
Stockholm: KTH , 2002. , x, 86 p.
Series
Trita-FYS, ISSN 0280-316X ; 2002:44
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-3449ISBN: 91-7283-389-0 (print)OAI: oai:DiVA.org:kth-3449DiVA: diva2:9249
Public defence
2002-12-12, 00:00 (English)
Note
QC 20100521Available from: 2002-12-06 Created: 2002-12-06 Last updated: 2010-05-21Bibliographically approved
List of papers
1. Observation of superdeformed states in Mo-88
Open this publication in new window or tab >>Observation of superdeformed states in Mo-88
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1999 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 4, 391-397 p.Article in journal (Refereed) Published
Abstract [en]

High-spin states in Mo-88 were studied using the GAMMASPHERE germanium detector array in conjunction with the MICROBALL CsI(TI) charged-particle detector system. Three gamma-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational bands observed in the neighbouring A = 80 region have been identified and assigned to the nucleus Mo-88. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole deformation of beta(2) approximate to 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total routhian surface calculations. All three hands are assigned to two-quasi-particle proton configurations at superdeformed shape.

Place, publisher, year, edition, pages
New York: SPRINGER VERLAG, 1999
Keyword
QUADRUPOLE-MOMENT MEASUREMENT, DEFORMED INTRUDER BANDS, MASS REGION, TRANSITIONS, NUCLEI
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-12984 (URN)000084668500007 ()
Note

QC 20100520

Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2014-09-24Bibliographically approved
2. Favoured superdeformed states in 89TC
Open this publication in new window or tab >>Favoured superdeformed states in 89TC
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1999 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 3, 251-255 p.Article in journal (Refereed) Published
Abstract [en]

A superdeformed band consisting of a cascade of ten gamma-ray transitions has been identified and assigned to the nucleus Tc-89, close to the proton dripline. The quadrupole moment of the band (Q(t) = 6.7(-2.3)(+3.0) eb, as measured by the Residual Doppler Shift Method) as well as a large dynamic moment of inertia point to a highly elongated shape. With a relative population of approximately 15% of the gamma-ray flux in the Tc-89 exit channel, thp band is among the most intense superdeformed bands observed to date.

Place, publisher, year, edition, pages
New York: Springer-Verlag New York, 1999
Keyword
MASS REGION, BAND, TRANSITIONS, NUCLEI
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-12985 (URN)000083880100005 ()
Note

QC 20100521

Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2015-05-06Bibliographically approved
3. Superdeformation in 91Tc
Open this publication in new window or tab >>Superdeformation in 91Tc
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2000 (English)In: Physics Letters B, ISSN 0370-2693, Vol. 492, no 3-4, 245-253 p.Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2000
Keyword
quadrupole-moments, mass region, states, nuclei, bands, transitions
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-12995 (URN)10.1016/S0370-2693(00)01114-X (DOI)000165315700003 ()
Note

QC 20100521

Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2015-05-06Bibliographically approved
4. First observation of gamma-rays from the proton emitter Au-171
Open this publication in new window or tab >>First observation of gamma-rays from the proton emitter Au-171
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2003 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 16, no 4, 489-494 p.Article in journal (Refereed) Published
Abstract [en]

Gamma-rays from the alpha- and proton-unstable nuclide Au-171 have been observed for the first time. The gamma-rays were correlated with both a proton- and an alpha-particle decay branch, confirming that the nucleus decays by alpha and proton emission from a single (11/2(-)) state. The measurement confirms the previously determined half-lives for these particle decays but the present values are of higher precision. In addition, a longer half-life than determined in previous work was measured for the proton-unstable tentative ground state. The results are discussed in relation to structures in neighbouring nuclei and compared with a Strutinsky-type TRS calculation.

Keyword
NEUTRON-DEFICIENT, SHAPE COEXISTENCE, EXCITED STRUCTURES, NUCLEI, STATES, IDENTIFICATION, REGION, MASS, AU, HG
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-13006 (URN)10.1140/epja/i2002-10108-7 (DOI)000182790700005 ()
Note
QC 20100521Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2010-08-23Bibliographically approved
5. Spectroscopy of the neutron-deficient nuclide Pt-171
Open this publication in new window or tab >>Spectroscopy of the neutron-deficient nuclide Pt-171
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2003 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 17, no 1, 1-5 p.Article in journal (Refereed) Published
Abstract [en]

A number of previously unobserved gamma-rays emitted from the neutron-deficient nuclide Pt-171 have been identified using the recoil decay tagging technique. The level scheme has been updated using information from gamma-gamma coincidences and angular distribution measurements. To further confirm the assignments of the gamma-rays to Pt-171, the events were correlated with the alpha-decay of the daughter nucleus Os-167.

Keyword
SHAPE COEXISTENCE, EXCITED STRUCTURES, NUCLEI, STATES, ISOTOPES, IDENTIFICATION, REGION, HG
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-13002 (URN)000183545500001 ()
Note
QC 20100521Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2010-05-21Bibliographically approved
6. Collective rotational-vibrational transition in the very neutron-deficient nuclei (171,172)-Pt
Open this publication in new window or tab >>Collective rotational-vibrational transition in the very neutron-deficient nuclei (171,172)-Pt
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1998 (English)In: Physics Letters B, ISSN 0370-2693, Vol. 443, no 1-4, 69-76 p.Article in journal (Refereed) Published
Abstract [en]

Excited states have been identified for the first time in very neutron deficient Pt-171.172 nuclei using the recoil-or-decay tagging technique. The ground-state band in Pt-172 has been established up to I-pi = 8+. A similar level sequence, presumably built on the I-pi = 13/2(+) state, is observed for Pt-171. The data are compared with theoretical calculations based on the mean field approach and the random phase approximation and are put into the context of the systematics of platinum isotopes. (C) 1998 Elsevier Science B.V. All rights reserved.

Place, publisher, year, edition, pages
AMSTERDAM, NETHERLANDS: ELSEVIER SCIENCE, 1998
Keyword
SHAPE COEXISTENCE, PLATINUM ISOTOPES, MASS NUCLEI, BANDS, ALIGNMENT, STATES, DECAY
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-13004 (URN)10.1016/S0370-2693(98)01334-3 (DOI)000077763500012 ()
Note
QC 20100521Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2010-05-21Bibliographically approved
7. An educational tool for demonstrating the TOF-PET technique
Open this publication in new window or tab >>An educational tool for demonstrating the TOF-PET technique
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2001 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, Vol. 471, no 1-2, 200-204 p.Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
AMERICAN PHYSICAL SOC, 2001
Keyword
PET, TOF-PET, medical imaging
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-13005 (URN)10.1016/S0168-9002(01)00965-2 (DOI)000171206500039 ()
Note
QC 20100521Available from: 2010-05-21 Created: 2010-05-21 Last updated: 2010-05-21Bibliographically approved

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