DECAY OF ER-160-ASTERISK IN O-16+ND-144 AND NI-64+ZR-96 FUSION REACTIONS BARRETO JL, NICOLIS NG, SARANTITES DG, CHARITY RJ, SOBOTKA LG, STRACENER DW, HENSLEY DC, BEENE JR, BAKTASH C, HALBERT ML, THOENNESSEN M PHYSICAL REVIEW C-NUCLEAR PHYSICS
51: (5) 2584-2591 MAY 1995
Document type: Article
Language: English
Cited References: 34
Times Cited: 4
KeyWords Plus: HEAVY-ION-FUSION, ANGULAR-MOMENTUM DISTRIBUTIONS, SUBBARRIER FUSION, ENTRANCE-CHANNEL, BARRIER FUSION, RESPONSE CHARACTERISTICS, MULTIDETECTOR SYSTEM, NEUTRON EMISSION, CROSS-SECTIONS, INSTRUMENTATION
Addresses: BARRETO JL, WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831.
Publisher: AMER INST PHYSICS, WOODBURY
IDS Number: QY779
ISSN: 0556-2813
SEARCH FOR ENTRANCE CHANNEL EFFECTS IN THE DECAY OF THE YB-164 COMPOUND NUCLEUS AT E-ASTERISK-APPROXIMATE-TO-54 MEV BARRETO JL, NICOLIS NG, SARANTITES DG, CHARITY RJ, SOBOTKA LG, STRACENER DW, HENSLEY DC, BEENE JR, BAKTASH C, HALBERT M, THOENNESSEN M PHYSICAL REVIEW C-NUCLEAR PHYSICS
48: (6) 2881-2894 DEC 1993
Cited References: 43
Times Cited: 15
Abstract: The existence of entrance channel effects in the decay of 164Yb*, formed at E* almost-equal-to 54 MeV in the reactions O-16 + Sm-148 and 64Ni + Mo-100 is investigated. Evaporation residue cross sections, entry state gamma-ray fold distributions as well as energy and angular distributions of exit-channel selected charged particles were obtained for each reaction, using 4pi detection systems for both particles and gamma rays. In the 64Ni-induced reaction, the center-of-mass alpha-particle angular distributions were found to be symmetric around 90-degrees indicating emission from a fully equilibrated compound nucleus. However, the corresponding angular distributions in the O-16-induced reaction show a forward component which exclusively affects the population of the alphaxn residue channels. The gamma-ray fold distributions for the alphaxn and xn channels show differences depending on the entrance channel as reported previously for similar systems. These differences can be understood in terms, of contributions from the equilibrium decay of incompletely fused O-16 with Sm-148 and the mapping of the compound nucleus spin distributions, obtained from realistic fusion models, to the evaporation residue gamma-ray fold distributions. It is concluded that the initial population of the compound nucleus is the only reason for the observed differences in the decay of 164Yb* populated in these reactions.
KeyWords Plus: HEAVY-ION FUSION, EVEN-EVEN NUCLIDES, ANGULAR-MOMENTUM, SUBBARRIER FUSION, NEUTRON EMISSION, CROSS-SECTIONS, RESPONSE CHARACTERISTICS, MULTIDETECTOR SYSTEM, SUPPRESSION, COLLISIONS
Addresses: BARRETO JL, WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. OAK RIDGE NATL LAB, OAK RIDGE, TN 37830.
IDS Number: MM348
THE TUBE - A SIMPLE 4-PI DETECTOR FOR ENHANCING CHANNELS IN GAMMA-RAY SPECTROSCOPY EXPERIMENTS HUA PF, SARANTITES DG, SOBOTKA LG, BARRETO JL, KIROV A NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
330: (1-2) 121-124 JUN 10 1993
Cited References: 9
Times Cited: 2
Abstract: A simple 4pi charged-particle sensitive detector useful for gamma-ray spectroscopy is described. The detector is a plastic scintillator tube, which surrounds the target. The tube is segmented into four optically isolated cylindrical arcs. The tube is an efficient charged particle hit detector with a very small photon interaction probability.
Addresses: HUA PF, WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130.
Publisher: ELSEVIER SCIENCE BV, AMSTERDAM
IDS Number: LD735
ISSN: 0168-9002
INTERMEDIATE-MASS FRAGMENT DECAY OF THE NECK ZONE FORMED IN PERIPHERAL BI-209+XE-136 COLLISIONS AT E(LAB)/A=28 MEV TOKE J, LOTT B, BALDWIN SP, QUEDNAU BM, SCHRODER WU, SOBOTKA LG, BARRETO J, CHARITY RJ, SARANTITES DG, STRACENER DW, DESOUZA RT PHYSICAL REVIEW LETTERS
75: (16) 2920-2923 OCT 16 1995
Cited References: 37
Times Cited: 30
Abstract: Intermediate-mass fragments (IMF) from the Bi-209+Xe-136 reaction at E(lab)/A = 28 MeV have been measured in coincidence with other reaction products, using a highly efficient 4 pi detector setup. Their emission patterns exhibit features consistent with dynamical fragmentation of a neck zone between the reaction partners, in addition to sequential statistical emission. In peripheral collisions with an average of 0.3 GeV of dissipated kinetic energy, the dynamical process accounts for 0.24 of the observed IMF multiplicity of 0.33.
KeyWords Plus: LIGHT CHARGED-PARTICLE, NUCLEAR COLLISIONS, EMISSION, FISSION, TRANSPORT, DROPS
Addresses: TOKE J, UNIV ROCHESTER, DEPT CHEM, ROCHESTER, NY 14627. UNIV ROCHESTER, NUCL STRUCT RES LAB, ROCHESTER, NY 14627. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. INDIANA UNIV, DEPT CHEM, BLOOMINGTON, IN 47405. INDIANA UNIV, CYCLOTRON FACIL, BLOOMINGTON, IN 47405.
IDS Number: RZ341
ISSN: 0031-9007
DYNAMICAL PRODUCTION OF INTERMEDIATE-MASS FRAGMENTS IN PERIPHERAL BI-209+XE-136 COLLISIONS AT E(LAB)/A=28 MEV TOKE J, LOTT B, BALDWIN SP, QUEDNAU BM, SCHRODER WU, SOBOTKA LG, BARRETO J, CHARITY RJ, GALLAMORE L, SARANTITES DG, STRACENER DW, DESOUZA RT NUCLEAR PHYSICS A
583: C519-C524 FEB 6 1995
Cited References: 13
Times Cited: 5
Abstract: Intermediate-mass fragments (IMF) from the reaction Bi-209+Xe-136 at E(lab)/A=28 MeV have been measured in coincidence with other charged reaction products, as well as with neutrons. The IMF emission patterns are seen to exhibit signatures of two mechanisms - statistical emission from the fully accelerated massive reaction partners and a fast dynamical emission from a single effective source. The latter mechanism, possibly involving a multiple neck rupture, becomes dominating for least dissipative collisions characterized by low associated light particle multiplicities.
KeyWords Plus: EMISSION
Addresses: TOKE J, UNIV ROCHESTER, DEPT CHEM, ROCHESTER, NY 14627. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. MICHIGAN STATE UNIV, E LANSING, MI 48824.
IDS Number: QG530
ISSN: 0375-9474
DISSIPATIVE ORBITING IN BI-209+XE-136 COLLISIONS AT E(LAB)/A=28 MEV BALDWIN SP, LOTT B, SZABO BM, QUEDNAU BM, SCHRODER WU, TOKE J, SOBOTKA LG, BARRETO J, CHARITY RJ, GALLAMORE L, SARANTITES DG, STRACENER DW, DESOUZA RT PHYSICAL REVIEW LETTERS
74: (8) 1299-1302 FEB 20 1995
Cited References: 23
KeyWords Plus: HEAVY-ION COLLISIONS, STATISTICAL MULTIFRAGMENTATION, NUCLEAR COLLISIONS, TRANSPORT, MODEL, DYNAMICS, PARTICLE
Addresses: BALDWIN SP, UNIV ROCHESTER, DEPT CHEM, ROCHESTER, NY 14627. UNIV ROCHESTER, NUCL STRUCT RES LAB, ROCHESTER, NY 14627. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. MICHIGAN STATE UNIV, DEPT PHYS, E LANSING, MI 48824. MICHIGAN STATE UNIV, NATL SUPERCOND CYCLOTRON LAB, E LANSING, MI 48824.
IDS Number: QH293
PROLATE OBLATE BAND MIXING AND NEW BANDS IN HG-182 BINDRA KS, HUA PF, BABU BRS, BAKTASH C, BARRETO J, CULLEN DM, DAVIDS CN, DENG JK, GARRETT JD, HALBERT ML, HAMILTON JH, JOHNSON NR, KIROV A, KORMICKI J, LEE IY, MA WC, MCGOWAN FK, RAMAYYA AV, SARANTITES DG, SORAMEL F, WINCHELL D PHYSICAL REVIEW C-NUCLEAR PHYSICS
51: (1) 401-404 JAN 1995
Document type: Note
Cited References: 11
Times Cited: 6
KeyWords Plus: SHAPE, HG
Addresses: BINDRA KS, VANDERBILT UNIV, DEPT PHYS, NASHVILLE, TN 37235. ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831. UNISOR, OAK RIDGE, TN 37831.
IDS Number: QD118
TIME-SCALE FOR PROTON EMISSION FROM HIGHLY EXCITED PROJECTILES CHARITY RJ, SOBOTKA LG, VANBUREN G, TIBBALS FA, BARRETO J, BOWMAN DR, CHARTIER M, DINIUS J, FOX D, GELBKE CK, HANDZY DO, HSI WC, HUA PF, KIROV AS, LISA MA, LYNCH WG, PEASLEE GF, PHAIR L, SARANTITES DG, SCHWARZ C, DESOUZA RT, TSANG MB, WILLIAMS C PHYSICS LETTERS B
323: (2) 113-117 MAR 10 1994
Cited References: 10
Abstract: Highly fragmented exit channels produced by the decay of excited Mg-24 projectiles were detected. The longitudinal velocity spectra of protons and alpha particles from such channels are offset. This offset is consistent with post-breakup Coulomb accelerations from the Au-197 target nuclei implying that the protons were emitted within 3 x 10(-22) S after the target-projectile separation.
Addresses: CHARITY RJ, WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. MICHIGAN STATE UNIV, NATL SUPERCONDUCTING CYCLOTRON LAB, E LANSING, MI 48824. INDIANA UNIV, DEPT CHEM, BLOOMINGTON, IN 47405.
IDS Number: NA373
ISSN: 0370-2693
MECHANISM FOR THE DISASSEMBLY OF EXCITED O-16 PROJECTILES INTO 4 ALPHA-PARTICLES CHARITY RJ, BARRETO J, SOBOTKA LG, SARANTITES DG, STRACENER DW, CHBIHI A, NICOLIS NG, AUBLE R, BAKTASH C, BEENE JR, BERTRAND F, HALBERT M, HENSLEY DC, HOREN DJ, LUDEMANN C, THOENNESSEN M, VARNER R PHYSICAL REVIEW C-NUCLEAR PHYSICS
46: (5) 1951-1967 NOV 1992
Cited References: 27
Times Cited: 18
Abstract: The decay of excited O-16 projectiles into the four alpha particle exit channel has been investigated. The projectiles, with bombarding energies of E/A = 25 MeV, were excited through peripheral interactions with Tb-159 target nuclei. A 4pi counter was used to detect both the projectile alpha particles and the light charged particles evaporated from the target nucleus. Criteria for selecting true O-16-->4alpha events with the minimum contamination from incorrectly identified events were examined. The distribution of relative angles between the four alpha particles in their center of mass frame was compared to simulations of O-16 decay by sequential decay mechanisms. The relative angles were shown to be consistent with a sequential evaporation mechanism if a nonzero angular momentum is assumed for the excited projectile. The momentum distribution of the alpha particles in the reaction plane was examined and found to be anisotropic for high projectile excitation energies. This anisotropy was shown to be consistent with Coulomb interactions between the first emitted alpha particle and the target nucleus, which would indicate that the lifetime of the projectile is very short, on the order of 10(-22) s.
KeyWords Plus: HEAVY-ION REACTIONS, 32.5 MEV NUCLEON, ENERGY-LEVELS, LIGHT-NUCLEI, COLLISIONS, EMISSION, MODELS
Addresses: CHARITY RJ, WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. OAK RIDGE NATL LAB, OAK RIDGE, TN 37830.
IDS Number: JX832
BINARY CHARACTER OF HIGHLY DISSIPATIVE BI-209 + XE-136 COLLISIONS AT ELAB/A = 28.2 MEV LOTT B, BALDWIN SP, SZABO BM, QUEDNAU BM, SCHRODER WU, TOKE J, SOBOTKA LG, BARRETO J, CHARITY RJ, GALLAMORE L, SARANTITES DG, STRACENER DW, DESOUZA RT PHYSICAL REVIEW LETTERS
68: (21) 3141-3144 MAY 25 1992
Cited References: 21
Times Cited: 50
Abstract: Exclusive measurements of neutrons and charged products have been performed using a combination of 4-pi neutron and 4-pi charged-particle detectors. The maximum observed energy dissipation corresponds to only approximately one-half of the available kinetic energy. For any degree of dissipation, the velocity distributions of charged particles are characteristic of sequential emission following binary collisions. The data imply that central collisions also lead to bimodal emission patterns or that they are not sufficiently well isolated by the requirement of high particle multiplicities,
KeyWords Plus: NUCLEAR MULTIFRAGMENTATION, HOT NUCLEI, COLLISIONS, FRAGMENTS
Addresses: LOTT B, UNIV ROCHESTER, DEPT CHEM, ROCHESTER, NY 14627. UNIV ROCHESTER, NUCL STRUCT RES LAB, ROCHESTER, NY 14627. WASHINGTON UNIV, DEPT CHEM, ST LOUIS, MO 63130. MICHIGAN STATE UNIV, DEPT PHYS, E LANSING, MI 48824. MICHIGAN STATE UNIV, NATL SUPERCOND CYCLOTRON LAB, E LANSING, MI 48824.
IDS Number: HV466
CHARGED-PARTICLE DAMAGE STUDIES OF YBA2CU3O7 BARRETO J, MATTIEVICH E, PEREIA R, DASILVEIRA MF, GONCALVES ZC, DOSSANTOS GR JOURNAL OF MATERIALS SCIENCE LETTERS
8: (6) 689-690 JUN 1989
Cited References: 14
Times Cited: 0
Addresses: BARRETO J, UNIV FED RIO DE JANEIRO, INST FIS, CP 68 528, BR-21945 RIO DE JANEIRO, RJ, BRAZIL. CNEN, INST ENGN NUCL, BR-21949 RIO DE JANEIRO, RJ, BRAZIL.
Publisher: CHAPMAN HALL LTD, LONDON
IDS Number: U9381
ISSN: 0261-8028
EXCITATION-FUNCTION AND HALF-LIFE FOR THE FISSION ISOMER PU-240M FROM THE U-238(ALPHA, 2N) PU-240M REACTION DEBARROS S, DEMAGALHAES SD, WOLF H, BARRETO J, EICHLER J, LISBONA N, DESOUZA IO, VIANNA DM ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI
323: (1) 101-104 1986
Document type: Article Times Cited: 2
Addresses: DEBARROS S, UNIV FED RIO DE JANEIRO, INST FIS, CIDADE UNIV, CX POSTAL 68528, BR-21944 RIO DE JANEIRO, BRAZIL.
Publisher: SPRINGER VERLAG, NEW YORK
IDS Number: AYT79
ISSN: 0939-7922
FUSION OF THE CA-40+CA-40 SYSTEM BARRETO J, AUGER G, LANGEVIN M, PLAGNOL E PHYSICAL REVIEW C-NUCLEAR PHYSICS
27: (3) 1335-1338 1983
Cited References: 12
Addresses: INST PHYS NUCL, F-91406 ORSAY, FRANCE.
IDS Number: QG584
FORMATION AND DEEXCITATION OF THE RB-79 COMPOUND NUCLEUS BARRETO J, LANGEVIN M, DETRAZ C NUCLEAR PHYSICS A
384: (1-2) 211-240 1982
Cited References: 56
IDS Number: PB487
ABSENCE OF CLOSED SHELL EFFECT IN THE FUSION REACTION CA-40+CA-48 AT 330 MEV BARRETO J, TASSANGOT L, STEPHAN C, GARRON JP, LANGEVIN M PHYSICAL REVIEW C-NUCLEAR PHYSICS
25: (3) 1641-1643 1982
Addresses: BARRETO J, INST PHYS NUCL, BP 1, F-91406 ORSAY, FRANCE.
IDS Number: NH888
FUSION EXCITATION-FUNCTION OF THE CA-40+CA-40 SYSTEM CLOSE TO THE THRESHOLD TOMASI E, ARDOUIN D, BARRETO J, BERNARD V, CAUVIN B, MAGNAGO C, MAZUR C, NGO C, PIASECKI E, RIBRAG M NUCLEAR PHYSICS A
373: (2) 341-348 1982
Cited References: 7
Times Cited: 28
Addresses: TOMASI E, CEN SACLAY, DEPT PHYS NUCL, MF, F-91191 GIF SUR YVETTE, FRANCE.
IDS Number: MY971
COMPLETE FUSION MECHANISM IN O-16+CU-63 REACTION LANGEVIN M, BARRETO J, DETRAZ C PHYSICAL REVIEW C-NUCLEAR PHYSICS
14: (1) 152-159 1976
Cited References: 24
IDS Number: CA327
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