5 research outputs found
A CsI hodoscope on CSHINE for Bremsstrahlung {\gamma}-rays in Heavy Ion Reactions
Bremsstrahlung production in heavy ion reactions at Fermi energies
carries important physical information including the nuclear symmetry energy at
supra-saturation densities. In order to detect the high energy Bremsstrahlung
rays, a hodoscope consisting of 15 CsI(Tl) crystal read out by photo
multiplier tubes has been built, tested and operated in experiment. The
resolution, efficiency and linear response of the units to rays have
been studied using radioactive source and reactions. The
inherent energy resolution of is obtained.
Reconstruction method has been established through Geant 4 simulations,
reproducing the experimental results where comparison can be made. Using the
reconstruction method developed, the whole efficiency of the hodoscope is about
against the emissions at the target position,
exhibiting insignificant dependence on the energy of incident rays
above 20 MeV. The hodoscope is operated in the experiment of Kr +
Sn at 25 MeV/u, and a full energy spectrum up to 80 MeV has
been obtained.Comment: 9 pages, 19 figure
Probing high-momentum component in nucleon momentum distribution by neutron-proton bremsstrahlung {\gamma}-rays in heavy ion reactions
The high momentum tail (HMT) of nucleons, as a signature of the short-range
correlations in nuclei, has been investigated by the high-energy bremsstrahlung
rays produced in Kr + Sn at 25 MeV/u. The energetic
photons are measured by a CsI(Tl) hodoscope mounted on the spectrometer CSHINE.
The energy spectrum above 30 MeV can be reproduced by the IBUU model
calculations incorporating the photon production channel from process in
which the HMTs of nucleons is considered. A non-zero HMT ratio of about
is favored by the data. The effect of the capture channel is
demonstrated
Revisit to the yield ratio of triton and He as an indicator of neutron-rich neck emission
The neutron rich neck zone created in heavy ion reaction is experimentally
probed by the production of the isobars. The energy spectra and angular
distributions of triton and He are measured with the CSHINE detector in
Kr +Pb reactions at 25 MeV/u. While the energy spectrum of
He is harder than that of triton, known as "He-puzzle", the yield
ratio presents a robust rising trend with the polar angle in
laboratory. Using the fission fragments to reconstruct the fission plane, the
enhancement of out-plane is confirmed in comparison to the
in-plane ratios. Transport model simulations reproduce qualitatively the
experimental trends, but the quantitative agreement is not achieved. The
results demonstrate that a neutron rich neck zone is formed in the reactions.
Further studies are called for to understand the clustering and the isospin
dynamics related to neck formation
Probing high-momentum component in nucleon momentum distribution by neutron-proton bremsstrahlung γ-rays in heavy ion reactions
The high momentum tail (HMT) of nucleons, as a signature of the short-range correlations in nuclei, has been investigated by the high-energy bremsstrahlung γ rays produced in 86Kr+124Sn at 25 MeV/nucleon. The energetic photons are measured by a CsI(Tl) hodoscope mounted on the spectrometer CSHINE. The energy spectrum ≥35 MeV can be reproduced by the Isospin- and Momentum-Dependent Boltzmann-Uehling-Uhlenbeck model calculations incorporating the photon production channel from np process in which the HMTs of nucleons is considered. A non-zero HMT ratio of about 15% is favored by the data. The effect of the capture channel np→dγ is demonstrated