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Analysis of High-Fold Gamma Data

Description: Historically, {gamma}-{gamma} and {gamma}-{gamma}-{gamma} coincidence spectra were utilized to build nuclear level schemes. With the development of large detector arrays, it has became possible to analyze higher fold coincidence data sets. This paper briefly reports on software to analyze 4-fold coincidence data sets that allows creation of 4-fold histograms (hypercubes) of at least 1024 channels per side (corresponding to a 43 gigachannel data space) that will fit onto a few gigabytes of disk … more
Date: August 10, 1998
Creator: Beyer, C.J.; Cromaz, M. & Radford, D.C.
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Partner: UNT Libraries Government Documents Department
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Damping in Yb nuclei

Description: In a mixture of three Yb nuclei, we find the rotational damping widths vary from 180 keV at 1.1 MeV {gamma}-ray energy to 290 keV at 1.5 MeV, and the average compound damping widths (or spreading widths) vary from 40 keV at 1.1 MeV {gamma}-ray energy to 60 keV at 1.3 MeV. The simulations also suggest extensive motional narrowing.
Date: July 1, 2002
Creator: Stephens, F. S.; Deleplanque, M. A.; Lee, I. Y.; Ward, D.; Fallon, P.; Cromaz, M. et al.
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Partner: UNT Libraries Government Documents Department
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The N=90 transitional nuclei {sup 150}Nd and {sup 152}Sm revisited

Description: The purpose of this paper is to show that recent data on the ground-state band and excited states based on the 0{sub 2}{sup +} level in {sup 15}Nd and {sup 152}Sm, especially the measured B(E2) values, can be well described by including a {Delta}K = 0 coupling between rotational bands. This is contrary to recent statements in the literature. The experimental data are compared with models which have supported the widely differing interpretations of these transitional nuclei. These interpretation… more
Date: January 21, 2003
Creator: Clark, R. M.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Gorgen, A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Studying neutron-rich 18 N in fusion-evaporation reactions

Description: Light neutron-rich nuclei provide an excellent opportunity to study the changes in nuclear shell structure that occur with increasing neutron number and are an important testing ground for shell model theories. Probably one of the most striking examples of shell modification is the occurrence of intruder ground states, which signal an inversion of the normal shell ordering. Intruder ground states are observed around {sup 32}Mg (Z=10-12), ''the island of inversion'', and in {sup 11}Be. An analog… more
Date: July 28, 2006
Creator: Wiedeking, M.; Fallon, P.; Bernstein, L.; Macchiavelli, A.; Phair, L.; Burke, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Order-to-chaos transition in rotational nuclei

Description: The authors have studied the narrow (valley-ridge) structure in the {gamma}-ray spectrum following a heavy-ion fusion reaction that produces several ytterbium nuclei. The intensity of this structure can be quantitatively related to the average chaotic behavior in these nuclei and they have traced this behavior from nearly fully ordered to nearly fully chaotic.
Date: May 13, 2004
Creator: Stephens, F. S.; Deleplanque, M. A.; Lee, I. Y.; Macchiavelli, A. O.; Ward, D.; Fallon, P. et al.
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Partner: UNT Libraries Government Documents Department
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Searching for E(5) behavior in nuclei

Description: The properties of even-even nuclei with 30 {le} Z {le} 82, A {ge} 60 have been examined to find examples displaying the characteristics of E(5) critical-point behavior for the shape transition from a spherical vibrator to a triaxially soft rotor. On the basis of the known experimental state energies and E2 transition strengths, the best candidates that were identified are {sup 102}Pd, {sup 106,108}Cd, {sup 124}Te, {sup 128}Xe, and {sup 134}Ba. The closest agreement between experimental data and… more
Date: January 1, 2004
Creator: Clark, R. M.; Cromaz, M.; Deleplanque, M. A.; Descovich, M.; Diamond, R. M.; Fallon, P. et al.
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Partner: UNT Libraries Government Documents Department
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Quadrupole moments of wobbling excitations in 163Lu

Description: Lifetimes of states in the triaxial strongly deformed bands of {sup 163}Lu have been measured in a Gammasphere experiment using the Doppler-shift attenuation method. The bands are interpreted as wobbling-phonon excitations from the characteristic electromagnetic properties of the transitions connecting the bands. Quadrupole moments were extracted for the 0-phonon yrast band and, for the first time, for the 1-phonon wobbling band. The very similar results found for both bands suggest a similar i… more
Date: January 1, 2004
Creator: Gorgen, A.; Clark, R. M.; Cromaz, M.; Fallon, P.; Hagemann, G. B.; Hubel, H. et al.
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Partner: UNT Libraries Government Documents Department
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In-beam gamma-ray spectroscopy of target fragmentation

Description: Fragmentation reactions, typically performed at energies {approx}E/A>50 MeV, produce neutron-rich nuclei but leave little angular momentum in the residues. In this work we have examined the product distribution and angular momentum input for a {sup 12}C beam at 30 MeV/A on a thick (40 mg/cm{sup 2}) target of {sup 51}V, testing the feasibility of in-beam gamma-ray spectroscopy study of target fragments at this lower energy. This technique allows the study of some neutron-rich nuclei to modera… more
Date: October 6, 2004
Creator: Rodriguez-Vieitez, E.; Lee, I. Y.; Ward, D.; Fallon, P.; Clark, R. M.; Cromaz, M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Very extended shapes in 108Cd: evidence for the occupation of 'hyper-intruder' orbitals

Description: High-spin states in {sup 108}Cd were studied following the reaction {sup 64} Ni({sup 48}Ca,4n) at a beam energy of 207 MeV. Gamma rays were detected using the Gammasphere array. Two rotational bands have been observed at very high angular momentum. Measurements of fractional Doppler shifts yielded lower limits for the quadrupole moments and showed that the observed structures are at least as deformed as the superdeformed structures e.g. in the A {approx} 150 region, and possibly exceed a 2:1 ax… more
Date: July 1, 2002
Creator: Gorgen, A.; Clark, R. M.; Fallon, P.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Population of Nuclei Via 7Li-Induced Binary Reactions

Description: The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduc… more
Date: August 9, 2005
Creator: Clark, R. M.; Phair, L. W.; Descovich, M.; Cromaz, M.; Deleplanque, M. A.; Fallon, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Aspects of the Coriolis Interaction in U235

Description: We have performed three separate experiments at LBNL's 88-Inch Cyclotron over a period of several years in which {sup 235}U (thick target) was Coulomb-excited. It involved stand-alone experiments with Gammasphere and with the 8PI Spectrometer using {sup 136}Xe beams at 720 MeV, and a CHICO-Gammasphere experiment with an {sup 40}Ar beam at 180 MeV. In addition to extending the known negative-parity bands to high spin, we have assigned levels in some seven positive-parity bands which are in some … more
Date: January 1, 2005
Creator: Ward, D.; Clark, R. M.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Deducing the 237U(n,f) cross-section using the Surrogate Ratio Method

Description: The authors have deduced the {sup 237}U(n,f) cross-section over an equivalent neutron energy range of 0 to 20 MeV using the Surrogate Ratio method. A 55 MeV {sup 4}He{sup 2+} beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions {sup 238}U({alpha},{alpha}'f) and {sup 236}U({alpha},{alpha}'f). The {sup 238}U reaction was a surrogate for {sup 237}U(n,f) and the {sup 236}U reaction was used as a surrogate for {sup 235}U(n,f).… more
Date: August 16, 2005
Creator: Burke, J. T.; Bernstein, L. A.; Escher, J.; Ahle, L.; Church, J. A.; Dietrich, F. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Deducing the 237U(n,f) cross-section using the Surrogate Ratio Method

Description: The authors have deduced the cross section for {sup 237}U(n,f) over an equivalent neutron energy range from 0 to 20 MeV using the Surrogate Ratio method. A 55 MeV {sup 4}He beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions: {sup 238}U({alpha},{alpha}{prime}f) and {sup 236}U({alpha},{alpha}{prime}f). The {sup 238}U reaction was a surrogate for {sup 237}U(n,f) and the {sup 236}U reaction was used as a surrogate for {sup … more
Date: December 29, 2005
Creator: Burke, J. T.; Bernstein, L. A.; Escher, J.; Ahle, L.; Church, J. A.; Dietrich, F. S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Very extended shapes in the A~;110 region

Description: High-angular-momentum states in {sup 108}Cd were populated via the {sup 64}Ni({sup 48}Ca,4n) reaction at a beam energy of 207 MeV. Gamma rays were detected using the Gammasphere array. A rotational band has been observed with a dynamic moment of inertia and deduced lower limit of the quadrupole moment suggesting a major-to-minor axis ratio larger than 1.8:1, placing it among the most deformed structures identified in any nucleus, to date.
Date: September 12, 2001
Creator: Clark, R. M.; Fallon, P.; Gorgen, A.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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