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Electromagnetic properties of {sup 181}Ir: Evidence of {beta}-stretching?

Description: We have calculated the B(Ml)/B(E2) ratios in {sup 18l}Ir within a shape-fixed particle + rotor model, in order to investigate how sensitive these may be to the nuclear shapes under consideration, and whether or not there is evidence of shape coexistence in the electromagnetic data alone. The model calculations employed the same Woods-Saxon potential that has been used previously for TRS and bandhead calculations and all parameters have been taken at their standard values, without any adjustment… more
Date: December 31, 1991
Creator: Garg, U.; Reviol, W. & Semmes, P.
Partner: UNT Libraries Government Documents Department
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Shell model at GAMMASPHERE: Studies in the A {approx} 96 region

Description: High-spin states in {sup 94,95}Mo, {sup 94,95,96}Tc, {sup 96,97,98}Ru and {sup 97,98}Rh were populated via the {sup 65}Cu({sup 36}S, xpyn) reactions at 142 MeV. We have observed about 300 new transitions belonging to these nuclei, and their level schemes have been extended up to a spin of J {approx} 20{h_bar} and an excitation energy of E{sub x} {approx} 12--14 MeV. Information on the high spin structure for {sup 96}Tc and {sup 98}Rh has been obtained for the first time. Spherical shell model c… more
Date: December 1995
Creator: Garg, U.; Ghugre, S. S. & Kharraja, B.
Partner: UNT Libraries Government Documents Department
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Unexpected structure in the E2 quasicontinuum spectrum of /sup 154/Dy

Description: The evolution of the ..gamma.. quasicontinuum spectrum with neutron number has been investigated in the sequence of dysprosium isotopes /sup 152,154,156/Dy. The three nuclei display a pronounced collective E2 component. In /sup 154/Dy this component shows an unexpected splitting into two distinct parts, signifying a structural change along the ..gamma.. cascade. The E2 and statistical components can be reproduced in simple ..gamma.. cascade calculations; in /sup 152/Dy and /sup 156/Dy only rota… more
Date: January 1, 1988
Creator: Holzmann, R.; Khoo, T. L.; Ma, W. C.; Ahmad, I.; Dichter, B. K.; Emling, H. et al.
Partner: UNT Libraries Government Documents Department
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Electromagnetic properties of sup 181 Ir: Evidence of. beta. -stretching

Description: We have calculated the B(Ml)/B(E2) ratios in {sup 18l}Ir within a shape-fixed particle + rotor model, in order to investigate how sensitive these may be to the nuclear shapes under consideration, and whether or not there is evidence of shape coexistence in the electromagnetic data alone. The model calculations employed the same Woods-Saxon potential that has been used previously for TRS and bandhead calculations and all parameters have been taken at their standard values, without any adjustment… more
Date: January 1, 1991
Creator: Garg, U.; Reviol, W. (Notre Dame Univ., IN (United States). Dept. of Physics) & Semmes, P. (Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics)
Partner: UNT Libraries Government Documents Department
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Higher superdeformed band members in {sup 190}Hg: Evidence for a band interaction?

Description: The superdeformed band of {sup 190}Hg has been traced up to a frequency {Dirac_h} {ge} 0.4 MeV by combining data from several experiments. A distinct change in the slope of the dynamic moment of inertia J{sup 2} vs {Dirac_h} is observed at {Dirac_h} = 0.32 MeV. This result is interpreted as evidence for a band interaction at the highest frequencies. Possible interpretations are reviewed.
Date: July 1, 1992
Creator: Bearden, I. G.; Daly, P. J.; Janssens, R. V. F.; Carpenter, M. P.; Ahmad, I.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Higher superdeformed band members in sup 190 Hg: Evidence for a band interaction

Description: The superdeformed band of {sup 190}Hg has been traced up to a frequency {Dirac h} {ge} 0.4 MeV by combining data from several experiments. A distinct change in the slope of the dynamic moment of inertia J{sup 2} vs {Dirac h} is observed at {Dirac h} = 0.32 MeV. This result is interpreted as evidence for a band interaction at the highest frequencies. Possible interpretations are reviewed.
Date: January 1, 1992
Creator: Bearden, I. G.; Daly, P. J.; Janssens, R. V. F.; Carpenter, M. P.; Ahmad, I.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Spectroscopy of {sup 96,97,98}Ru: Possible emergence of collectivity at N {ge} 52

Description: Detailed experimental information on high-spin states (up to {approximately} 20 {h_bar}) in the N {ge} 52 nuclei {sup 96,97,98}Ru has been obtained from gamma-ray spectroscopic studies following {sup 65}Cu({sup 36}S,pxn) reactions. The level schemes exhibit sequences of presumably negative-parity states linked by E2 transitions with monotonously increasing energies. These sequences coexist with the positive-parity yrast states where the transition energies are rather irregular. The negative-par… more
Date: December 31, 1992
Creator: Reviol, W.; Garg, U.; Aprahamian, A.; Davis, B. F.; Naguleswaran, S.; Walpe, J. C. et al.
Partner: UNT Libraries Government Documents Department
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Feeding and decay of superdeformed states

Description: The mechanisms for feeding and decay of superdeformed (SD) bands are examined. Data connected with both processes in {sup 192}Hg are compared with model calculations. The calculations successfully reproduce the data, suggesting that the mechanisms for both processes are understood. Constraints on the energy of the SD band energies and on the well-depths at low and high spins have been obtained. At the point of decay around spin 10, we suggest that the SD band is 3.3--4.3 MeV above the normal yr… more
Date: December 31, 1992
Creator: Khoo, T. L.; Lauritsen, T.; Ahmad, I.; Carpenter, M. P.; Fernandez, P. B.; Janssens, R. V. F. et al.
Partner: UNT Libraries Government Documents Department
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New results on superdeformed bands in Hg and Tl nuclei

Description: New results have been obtained on superdeformed states in [sup 190]Hg, [sup 191]Tl, and [sup 192]Tl. For [sup 190]Hg, the previously identified superdeformed band has been extended up to a rotational frequency of [Dirac h][omega] [ge] 0.40 MeV by combining data from several different experiments. The extracted dynamical moment of inertia J([sup 2]) vs [Dirac h][omega] exhibits a distinct change in slope at [Dirac h][omega] = 0.32 MeV. For [sup 191]Tl and [sup 192]Tl, two and six superdeformed b… more
Date: January 1, 1992
Creator: Carpenter, M. P.; Janssens, R. V. F.; Liang, Y.; Ahmad, I.; Henry, R. G.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Double blocking in the superdeformed {sup 192}Tl nucleus

Description: Six superdeformed bands have been found in the nucleus {sup 192}Tl. For two of the bands, the dynamic moment of inertia J{sup (2)} is found to be constant with the rotational frequency {Dirac_h}. This result can be understood in terms of Pauli blocking of quasiparticle alignments in intruder orbitals, and represents the first experimental evidence that the alignment of these intruders is responsible for the smooth rise in J{sup (2)} seen in other superdeformed nuclei of this mass region.
Date: August 1, 1992
Creator: Liang, Y.; Carpenter, M. P.; Janssens, R. V. F.; Ahmad, I.; Henry, R.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Entrance channel dependence in the population of the superdeformed bands in {sup 191}Hg and a model for the feeding mechanism

Description: The population of the superdeformed bands in {sup 191}Hg has been measured for two reactions with different mass asymmetry. No entrance channel effect was observed, in contrast to similar measurements in the A=150 region. To further elucidate this problem, the entry distribution for the superdeformed band in {sup 192}Hg was measured and a Monte Carlo model for the feeding was developed. The simulations suggest that the decision on trapping in the superdeformed well is made at the barrier betwee… more
Date: July 1, 1992
Creator: Lauritsen, T.; Soramel, F.; Khoo, T. L.; Janssens, R. V. F.; Ahmad, I.; Carpenter, M. P. et al.
Partner: UNT Libraries Government Documents Department
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New results on superdeformed bands in Hg and Tl nuclei

Description: New results have been obtained on superdeformed states in {sup 190}Hg, {sup 191}Tl, and {sup 192}Tl. For {sup 190}Hg, the previously identified superdeformed band has been extended up to a rotational frequency of {Dirac_h}{omega} {ge} 0.40 MeV by combining data from several different experiments. The extracted dynamical moment of inertia J({sup 2}) vs {Dirac_h}{omega} exhibits a distinct change in slope at {Dirac_h}{omega} = 0.32 MeV. For {sup 191}Tl and {sup 192}Tl, two and six superdeformed b… more
Date: December 31, 1992
Creator: Carpenter, M. P.; Janssens, R. V. F.; Liang, Y.; Ahmad, I.; Henry, R. G.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Decay out of the yrast superdeformed band in {sup 191}Hg.

Description: The excitation energies and spins of the yrast superdeformed band in {sup 191}Hg have been determined by analyzing the quasicontinuum spectrum connecting the superdeformed and normal-deformed states. The results from this analysis, combined with that given by one-step decay lines, give confident assignments of the spins and energies of the yrast superdeformed band in {sup 191}Hg.
Date: March 24, 1999
Creator: Sien, S.; Reiter, P.; Khoo, T.; Lauritsen, T.; Carpenter, M. P.; Ahmad, I. et al.
Partner: UNT Libraries Government Documents Department
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Spectroscopy of [sup 96,97,98]Ru: Possible emergence of collectivity at N [ge] 52

Description: Detailed experimental information on high-spin states (up to [approximately] 20 [h bar]) in the N [ge] 52 nuclei [sup 96,97,98]Ru has been obtained from gamma-ray spectroscopic studies following [sup 65]Cu([sup 36]S,pxn) reactions. The level schemes exhibit sequences of presumably negative-parity states linked by E2 transitions with monotonously increasing energies. These sequences coexist with the positive-parity yrast states where the transition energies are rather irregular. The negative-par… more
Date: January 1, 1992
Creator: Reviol, W.; Garg, U.; Aprahamian, A.; Davis, B.F.; Naguleswaran, S.; Walpe, J.C. et al.
Partner: UNT Libraries Government Documents Department
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Statistical gamma transitions in {sup 174}Hf

Description: Statistical spectrum extracted from the {sup 172}Yb({alpha},2n){sup 174}Hf reaction was fit with Monte Carlo simulations using a modified GDR E1 strength function and several formulations of the level density.
Date: August 1, 1992
Creator: Farris, L. P.; Cizewski, J. A.; Brinkman, M. J.; Henry, R. G.; Lee, C. S.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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In-beam studies of proton emitters using the Recoil-Decay Tagging method

Description: The last five years have witnessed a rapid increase in the volume of data on proton decaying nuclei. The path was led by decay studies with recoil mass separators equipped with double-sided Si strip detectors. The properties of many proton-decaying states were deduced, which triggered renewed theoretical interest in the process of proton decay. The decay experiments were closely followed by in-beam {gamma}-ray studies which extended one's knowledge of high-spin states of proton emitters. The un… more
Date: January 19, 2000
Creator: Seweryniak, D.; Woods, P. J.; Ressler, J.; Davids, C. N.; Heinz, A.; Sonzogni, A. et al.
Partner: UNT Libraries Government Documents Department
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GAMMASPHERE+FMA : a journey beyond the proton drip-line.

Description: The majority of experiments performed during the 2-year long stay of GAMMAS-PHERE at the Argonne National Laboratory aimed to study proton-rich nuclei far from the line of stability at and beyond the proton drip-line. A high reaction channel selectivity was required to assign in-beam {gamma}-ray transitions to weakly populated exotic nuclei in the presence of background from strong reaction channels. In many of the experiments this was achieved by using the Argonne fragment mass analyzer to sep… more
Date: November 30, 2000
Creator: Seweryniak, D.; Woods, P. J.; Ressler, J. J.; Davids, C. N.; Heinz, A.; Sonzogni, A. A. et al.
Partner: UNT Libraries Government Documents Department
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Superdeformation in the mercury nuclei

Description: We shall first summarize the present experimental situation concerning {sup 192}Hg, the nucleus regarded as the analog of {sup 152}Dy for this superdeformation (SD) region in that gaps are calculated to occur at large deformation for Z = 80 and N = 112. Proton and neutron excitations out of the {sup 192}Hg core will then be reviewed with particular emphasis on {sup 191}Hg and {sup 193}Tl. The presentation will conclude with a brief discussion on limits of the SD region for neutron deficient Hg … more
Date: January 1, 1990
Creator: Janssens, R. V. F.; Carpenter, M. P.; Fernandez, P. B.; Moore, E. F.; Ahmad, I.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Feeding and decay of superdeformed states

Description: The mechanisms for feeding and decay of superdeformed (SD) bands are examined. Data connected with both processes in [sup 192]Hg are compared with model calculations. The calculations successfully reproduce the data, suggesting that the mechanisms for both processes are understood. Constraints on the energy of the SD band energies and on the well-depths at low and high spins have been obtained. At the point of decay around spin 10, we suggest that the SD band is 3.3--4.3 MeV above the normal yr… more
Date: January 1, 1992
Creator: Khoo, T.L.; Lauritsen, T.; Ahmad, I.; Carpenter, M.P.; Fernandez, P.B.; Janssens, R.V.F. et al.
Partner: UNT Libraries Government Documents Department
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Population of superdeformed bands, the competition with fission, and the barrier between normal and superdeformed states

Description: In this paper we report on the entry points leading to superdeformed (SD) as well as normal bands. We find that, compared to normal bands, the entry spins for the SD bands are about 9 {h bar} higher, and the entry excitation energy 1--3 MeV colder. We also conclude that population of the SD bands represents successful competition against fission. SD bands in both the Dy and Hg regions are considered.
Date: January 1, 1990
Creator: Khoo, T. L.; Janssens, R. V. F.; Moore, E. F.; Ahmad, I.; Carpenter, M. P.; Chasman, R. R. et al.
Partner: UNT Libraries Government Documents Department
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Population of superdeformed bands and competition with fission

Description: Average entry points for superdeformed (SD) and normal states have been measured in {sup 191, 192}Hg and in {sup 152}Dy. Compared with normal states, the superdeformed states have entry spins {approximately} 10 h higher and internal excitation energies (U = E --- E{sub yrast}) at least 2 MeV lower for the Hg cases and about 8 MeV lower for {sup 152}Dy. By comparison with calculated {ell}- distributions of evaporation residues (ER), using CASCADE to compute the fission competition, we find that … more
Date: January 1, 1990
Creator: Moore, E. F.; Janssens, R. V. F.; Khoo, T. L.; Ahmad, I.; Carpenter, M. P.; Chasman, R. R. et al.
Partner: UNT Libraries Government Documents Department
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Double blocking in the superdeformed sup 192 Tl nucleus

Description: Six superdeformed bands have been found in the nucleus {sup 192}Tl. For two of the bands, the dynamic moment of inertia J{sup (2)} is found to be constant with the rotational frequency {Dirac h}. This result can be understood in terms of Pauli blocking of quasiparticle alignments in intruder orbitals, and represents the first experimental evidence that the alignment of these intruders is responsible for the smooth rise in J{sup (2)} seen in other superdeformed nuclei of this mass region.
Date: January 1, 1992
Creator: Liang, Y.; Carpenter, M. P.; Janssens, R. V. F.; Ahmad, I.; Henry, R.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Statistical gamma transitions in sup 174 Hf

Description: Statistical spectrum extracted from the {sup 172}Yb({alpha},2n){sup 174}Hf reaction was fit with Monte Carlo simulations using a modified GDR E1 strength function and several formulations of the level density.
Date: January 1, 1992
Creator: Farris, L. P.; Cizewski, J. A.; Brinkman, M. J.; Henry, R. G.; Lee, C. S. (Rutgers--the State Univ., New Brunswick, NJ (United States)); Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department
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Recent developments on the STAR detector system at RHIC

Description: The STAR detector system is designed to provide tracking, momentum analysis and particle identification for many of the mid-rapidity charged particles produced in collisions at the RHIC collider. A silicon vertex detector (SVT) provides three layers of tracking near the interaction point. This is followed by the main time projection chamber (TPC), which continues tracking out to 200 cm radial distance from the interaction region. The detector design also includes an electromagnetic calorimeter,… more
Date: December 1997
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department
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