B. Back - Academia.edu (original) (raw)
Papers by B. Back
Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c π − beams incident on a 197 Au... more Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c π − beams incident on a 197 Au target have been analyzed in order to deduce the possible existence and influence of thermal expansion. The average fragment kinetic energies are observed to increase systematically with fragment charge and to be nearly independent of excitation energy. Comparison of the data with statistical multifragmentation models indicates the onset of extra collective thermal expansion near an excitation energy of E*/A ≈ 5 MeV. However, this effect is weak relative to the radial expansion observed in heavy-ion-induced reactions, consistent with the interpretation that the latter expansion may be driven primarily by dynamical effects such as compression/decompression. The origin of the multifragmentation process [1], and its link to a nuclear liquid-gas phase
Journal of Physics: Conference Series, 2017
Cluster resonances in light heavy-ion systems like 12 C+ 12 C and 12 C+ 16 O may have a major imp... more Cluster resonances in light heavy-ion systems like 12 C+ 12 C and 12 C+ 16 O may have a major impact on astrophysics stellar scenarios. Resonant radiative capture reactions have been studied for these systems at energies at and slightly below their Coulomb barriers to investigate the possible 12 C-12 C and 12 C-16 O molecular origin of the resonances. Spins have been attributed to the resonances and specificities of their -decay have been identified. At deep sub-barrier energies, a fusion cross section measurement using the particle- coincidence technique is discussed for the 12 C+ 12 C system. A new project is presented to possibly extend the 12 C+ 12 C S low-energy S factor study.
Physical Review Letters, 1992
We have studied the strongly angular-momentum mismatched inelastic scattering reaction 12C(a2C,12... more We have studied the strongly angular-momentum mismatched inelastic scattering reaction 12C(a2C,12C(0~))I~C(0~), using highly segmented silicon " ~" ' stnp-,~eeeetors. A large enhancement is observed in the scattering cross section near a centex-of-mass energy of 32.5 MeV, with dominant angular momenta near L=14-16 h, which could be associated with highiy-deformed alpha-particle cluster configurations in 2aMg.
Physical Review Letters, 2005
Physical Review Letters, 1987
ABSTRACT
Physical Review C, 1993
The spontaneous fission decay of Cf has been analyzed in a statistical model with emphasis on des... more The spontaneous fission decay of Cf has been analyzed in a statistical model with emphasis on describing recently reported high energy pray spectra. An enhanced p emission in the range from 3 to 10 MeV which is observed for nearly symmetric mass splits is readily understood as a result of the difFerent fragment excitation energies. The model includes a viscous motion to the scission point with the possibility of prescission p emission. It was found that even with saddle-to-scission times of r"&66 x 10 s, the maximum consistent with prescission neutron multiplicities, prescission p rays are overwhelmed by fragment p rays. Thus, the recently reported strong angular anisotropy of p rays in the range E~= 8-12 MeV is unexplained within the present understanding of the fission process.
Physical Review C, 1996
Angular correlation techniques have been used to determine the spin of a strong resonance observe... more Angular correlation techniques have been used to determine the spin of a strong resonance observed in the 12C +12C(3-;9.64 MeV) inelastic scattering channel, at a bombarding energy of 33.5 MeV in the center-of-mass system. The alpha particles produced in the sequential decay 12C(3-)-->8Be(g.s.) + alpha0 were detected using four double-sided silicon strip detectors. The data are consistent with a spin assignment of Jpi=18+ for this resonance. The current results are compared to calculations of resonance behavior in this system from the band crossing model.
Journal of Physics G: Nuclear and Particle Physics, 2004
Acta Physica Hungarica, 2002
Chinese Physics Letters, 2010
AIP Conference Proceedings
We present an overview of the latest results for interactions of Au+Au ions at center-of-mass ene... more We present an overview of the latest results for interactions of Au+Au ions at center-of-mass energies of RADICAL:[[RADICAND:[SNN]]] of 56, 130 and 200 GeV obtained by the PHOBOS collaboration at the Relativistic Heavy Ion Collider (RHIC). These data have allowed us to perform an extensive study of the pseudorapidity density of primary charged particles as a function of incident energy,
The experimental program at the Fragment Mass Analyzer (FMA) at the ATLAS accelerator is well und... more The experimental program at the Fragment Mass Analyzer (FMA) at the ATLAS accelerator is well under way. Experiments have been carried out at the target position and at the focal plane. After a brief facility description, some recent experimental results are presented.
We present an overview of the latest results for interactions of Au+Au ions at center-of-mass ene... more We present an overview of the latest results for interactions of Au+Au ions at center-of-mass energies of RADICAL:[[RADICAND:[SNN]]] of 56, 130 and 200 GeV obtained by the PHOBOS collaboration at the Relativistic Heavy Ion Collider (RHIC). These data have allowed us to perform an extensive study of the pseudorapidity density of primary charged particles as a function of incident energy,
Physical Review Letters, 2001
Physical Review Letters, 1999
Comparison of the heating effect produced by 8 GeV/c pi- and antiproton beams incident on 197Au n... more Comparison of the heating effect produced by 8 GeV/c pi- and antiproton beams incident on 197Au nuclei has been conducted with the Indiana silicon sphere 4pi detector array. Event reconstruction indicates formation of thermal-like heavy residues with excitation energies up to 1.7 GeV. Enhanced energy deposition is observed for antiprotons relative to negative pions. For events with excitation energies that
Physical Review Letters, 2005
Physical Review Letters, 1984
ABSTRACT
Physical Review Letters, 1980
ABSTRACT
Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c π − beams incident on a 197 Au... more Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c π − beams incident on a 197 Au target have been analyzed in order to deduce the possible existence and influence of thermal expansion. The average fragment kinetic energies are observed to increase systematically with fragment charge and to be nearly independent of excitation energy. Comparison of the data with statistical multifragmentation models indicates the onset of extra collective thermal expansion near an excitation energy of E*/A ≈ 5 MeV. However, this effect is weak relative to the radial expansion observed in heavy-ion-induced reactions, consistent with the interpretation that the latter expansion may be driven primarily by dynamical effects such as compression/decompression. The origin of the multifragmentation process [1], and its link to a nuclear liquid-gas phase
Journal of Physics: Conference Series, 2017
Cluster resonances in light heavy-ion systems like 12 C+ 12 C and 12 C+ 16 O may have a major imp... more Cluster resonances in light heavy-ion systems like 12 C+ 12 C and 12 C+ 16 O may have a major impact on astrophysics stellar scenarios. Resonant radiative capture reactions have been studied for these systems at energies at and slightly below their Coulomb barriers to investigate the possible 12 C-12 C and 12 C-16 O molecular origin of the resonances. Spins have been attributed to the resonances and specificities of their -decay have been identified. At deep sub-barrier energies, a fusion cross section measurement using the particle- coincidence technique is discussed for the 12 C+ 12 C system. A new project is presented to possibly extend the 12 C+ 12 C S low-energy S factor study.
Physical Review Letters, 1992
We have studied the strongly angular-momentum mismatched inelastic scattering reaction 12C(a2C,12... more We have studied the strongly angular-momentum mismatched inelastic scattering reaction 12C(a2C,12C(0~))I~C(0~), using highly segmented silicon " ~" ' stnp-,~eeeetors. A large enhancement is observed in the scattering cross section near a centex-of-mass energy of 32.5 MeV, with dominant angular momenta near L=14-16 h, which could be associated with highiy-deformed alpha-particle cluster configurations in 2aMg.
Physical Review Letters, 2005
Physical Review Letters, 1987
ABSTRACT
Physical Review C, 1993
The spontaneous fission decay of Cf has been analyzed in a statistical model with emphasis on des... more The spontaneous fission decay of Cf has been analyzed in a statistical model with emphasis on describing recently reported high energy pray spectra. An enhanced p emission in the range from 3 to 10 MeV which is observed for nearly symmetric mass splits is readily understood as a result of the difFerent fragment excitation energies. The model includes a viscous motion to the scission point with the possibility of prescission p emission. It was found that even with saddle-to-scission times of r"&66 x 10 s, the maximum consistent with prescission neutron multiplicities, prescission p rays are overwhelmed by fragment p rays. Thus, the recently reported strong angular anisotropy of p rays in the range E~= 8-12 MeV is unexplained within the present understanding of the fission process.
Physical Review C, 1996
Angular correlation techniques have been used to determine the spin of a strong resonance observe... more Angular correlation techniques have been used to determine the spin of a strong resonance observed in the 12C +12C(3-;9.64 MeV) inelastic scattering channel, at a bombarding energy of 33.5 MeV in the center-of-mass system. The alpha particles produced in the sequential decay 12C(3-)-->8Be(g.s.) + alpha0 were detected using four double-sided silicon strip detectors. The data are consistent with a spin assignment of Jpi=18+ for this resonance. The current results are compared to calculations of resonance behavior in this system from the band crossing model.
Journal of Physics G: Nuclear and Particle Physics, 2004
Acta Physica Hungarica, 2002
Chinese Physics Letters, 2010
AIP Conference Proceedings
We present an overview of the latest results for interactions of Au+Au ions at center-of-mass ene... more We present an overview of the latest results for interactions of Au+Au ions at center-of-mass energies of RADICAL:[[RADICAND:[SNN]]] of 56, 130 and 200 GeV obtained by the PHOBOS collaboration at the Relativistic Heavy Ion Collider (RHIC). These data have allowed us to perform an extensive study of the pseudorapidity density of primary charged particles as a function of incident energy,
The experimental program at the Fragment Mass Analyzer (FMA) at the ATLAS accelerator is well und... more The experimental program at the Fragment Mass Analyzer (FMA) at the ATLAS accelerator is well under way. Experiments have been carried out at the target position and at the focal plane. After a brief facility description, some recent experimental results are presented.
We present an overview of the latest results for interactions of Au+Au ions at center-of-mass ene... more We present an overview of the latest results for interactions of Au+Au ions at center-of-mass energies of RADICAL:[[RADICAND:[SNN]]] of 56, 130 and 200 GeV obtained by the PHOBOS collaboration at the Relativistic Heavy Ion Collider (RHIC). These data have allowed us to perform an extensive study of the pseudorapidity density of primary charged particles as a function of incident energy,
Physical Review Letters, 2001
Physical Review Letters, 1999
Comparison of the heating effect produced by 8 GeV/c pi- and antiproton beams incident on 197Au n... more Comparison of the heating effect produced by 8 GeV/c pi- and antiproton beams incident on 197Au nuclei has been conducted with the Indiana silicon sphere 4pi detector array. Event reconstruction indicates formation of thermal-like heavy residues with excitation energies up to 1.7 GeV. Enhanced energy deposition is observed for antiprotons relative to negative pions. For events with excitation energies that
Physical Review Letters, 2005
Physical Review Letters, 1984
ABSTRACT
Physical Review Letters, 1980
ABSTRACT