Tue·Dec 8, 2020Tuesday·December 8, 2020

1. 01*

   Excitation energy and angular momentum dependence of the nuclear level density parameter around A$\approx$110

   Pratap Roy · S. Mukhopadhyay🇮🇳 · Mamta Aggarwal🇮🇳 · Deepak Pandit🇮🇳 · T. K. Rana · Samir Kundu · T. K. Ghosh🇮🇳 · K. Banerjee🇮🇳 · G. Mukherjee🇮🇳 · S. Manna · A. Sen · R. Pandey and 5 other authors

   Neutron kinetic energy spectra in coincidence with low-energy $\gamma$-ray multiplicities have been measured around $A\approx$ 110 in the ${}^{16}$O, ${}^{20}$Ne + ${}^{93}$Nb reactions in a compound nuclear excitation energy range of $\approx$ 90 - 140 MeV. The excitation energy (temperature) and angular momentum (spin) dependence of the inverse level density parameter $k$ has been investigated by comparing the experimental data with statistical Hauser-Feshbach calculation. In contrast to the available systematic in this mass region, the inverse level density parameter showed an appreciable increase as a function of the excitation energy. The extracted $k$-values at different angular momentum regions, corresponding to different $\gamma$-multiplicities also showed an overall increase with the average nuclear spins. The experimental results have been compared with a microscopic statistical-model calculation and found to be in reasonable agreement with the data. The results provide useful information to understand the variation of nuclear level density at high temperature and spins.

   nucl-exPRC(2021)·5 citations
2. 02*

   Nuclear level density and thermal properties of ${}^{115}$Sn from neutron evaporation

   Pratap Roy · K. Banerjee🇮🇳 · T. K. Rana · S. Kundu · Deepak Pandit🇮🇳 · N. Quang Hung · T. K. Ghosh🇮🇳 · S. Mukhopadhyay🇮🇳 · D. Mondal · G. Mukherjee🇮🇳 · S. Manna · A. Sen and 5 other authors

   The nuclear level density of ${}^{115}$Sn has been measured in an excitation energy range of $\sim$2 - 9 MeV using the experimental neutron evaporation spectra from the ${}^{115}$In($p,n$)${}^{115}$Sn reaction. The experimental level densities were compared with the microscopic Hartree-Fock BCS (HFBCS), Hartree-Fock-Bogoliubov plus combinatorial (HFB+C), and an exact pairing plus independent particle model (EP+IPM) calculations. It is observed that the EP+IPM provides the most accurate description of the experimental data. The thermal properties (entropy and temperature) of ${}^{115}$Sn have been investigated from the measured level densities. The experimental temperature profile as well as the calculated heat capacity show distinct signatures of a transition from the strongly-paired nucleonic phase to the weakly paired one in this nucleus.

   nucl-exEPJA(2021)·12 citations
3. 03*

   Detailed low-spin spectroscopy of 65Ni via neutron capture reaction

   C. Porzio🇮🇹 · C. Michelagnoli🇫🇷 · N. Cieplicka-Orynczak🇵🇱 · M. Sferrazza🇧🇪 · S. Leoni🇮🇹 · B. Fornal🇵🇱 · Y. Tsunoda🇯🇵 · T. Otsuka🇯🇵 · S. Bottoni🇮🇹 · C. Costache🇷🇴 · F. C. L. Crespi🇮🇹 · L. W. Iskra🇮🇹 and 8 other authors

   An extended investigation of the low-spin structure of the ${}^{65}$Ni nucleus was performed at the Institut Laue-Langevin, Grenoble, via the neutron capture reaction ${}^{64}$Ni(n,$\gamma$)${}^{65}$Ni, using the FIPPS HPGe array. The level scheme of ${}^{65}$Ni was significantly expanded, with 2 new levels and 87 newly found transitions. Angular correlation analyses were also performed, allowing us to assign spins and parities for a number of states, and to determine multipolarity mixing ratios for selected $\gamma$ transitions. The low-energy part of the experimental level scheme (up to about 1.4 MeV) was compared with Monte Carlo Shell Model calculations, which predict spherical shapes for all states, apart from the 9/2${}^{+}$ and the second excited 1/2${}^{-}$ states of oblate deformation.

   nucl-exPRC(2020)·2 citations
4. 04*

   Detailed investigation on the possibility of using EJ-299-33A plastic scintillator for fast neutron spectroscopy in large scale experiments

   Pratap Roy · K. Banerjee🇮🇳 · A. K. Saha · C. Bhattacharya🇮🇳 · J. K. Meenaa · P. Bhaskar · S. Mukhopadhyay🇮🇳 · S. Bhattacharya🇺🇸

   Detailed characterization of the newly available plastic scintillator (EJ-299-33A) having the pulse shape discrimination (PSD) property has been carried out in case of a large-sized detector (5 in.$\times$5 in.). The pulse height response of the scintillator for nearly mono-energetic neutrons has been reported in case of neutron energies E${}_n$ =3, 6 and 9 MeV. Important properties (figure-of-merit (FOM), time resolution, detection efficiency) of the detector has been compared with a commonly used liquid organic scintillator based detector of the same size coupled to the same PMT for uniformity in comparison. The results show that the plastic scintillator detector has about 12$\%$ better time resolution. However, the FOM and detection efficiency were found to be lower than that of the liquid scintillator detector by 40 - 50$\%$ and $\sim$25$\%$, respectively. The possibility of using the new plastic scintillator in large-scale nuclear physics experiments has been pointed out.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2018)·8 citations
5. 05*

   Interpretation of the quasiparticle plus triaxial rotor model

   Q. B. Chen🇩🇪 · S. Frauendorf🇺🇸

   We discuss in depth the application of the classical concepts for interpreting the quantal results from the triaxial rotor core without and with odd-particle. The corresponding limitations caused by the discreteness and finiteness of the angular momentum Hilbert space and the extraction of the relevant features from the complex wave function and distributions of various angular momentum components are discussed in detail. New methods based on spin coherent states and spin squeezed states are introduced. It is demonstrated that the spin coherent state map is a powerful tool to visualize the angular momentum geometry of rotating nuclei. The topological nature of the concepts of transverse and longitudinal wobbling is clarified and the transitional axis-flipregime is analysed for the first time.

   ↳ nucl-thnucl-ex2 citations
6. 06*

   Neutron Resonance Transmission Analysis with a Compact Deuterium-Tritium Neutron Generator

   Ethan A. Klein · Farheen Naqvi🇺🇸 · Jacob E. Bickus · Hin Y. Lee · Robert J. Goldston · Areg Danagoulian

   Neutron Resonance Transmission Analysis (NRTA) is a spectroscopic technique which uses the resonant absorption of neutrons in the epithermal range to infer the isotopic composition of an object. This spectroscopic technique has relevance in many traditional fields of science and nuclear security. NRTA in the past made use of large, expensive accelerator facilities to achieve precise neutron beams, significantly limiting its applicability. In this work we describe a series of NRTA experiments where we use a compact, low-cost deuterium-tritium (DT) neutron generator to produce short neutron beams (2.6~m) along with a ${}^6$Li-glass neutron detector. The time-of-flight spectral data from five elements -- silver, cadmium, tungsten, indium, and ${}^{238}$U -- clearly show the corresponding absorption lines in the 1-30 eV range. The experiments show the applicability of NRTA in this simplified configuration, and prove the feasibility of this compact and low-cost approach. This could significantly broaden the applicability of NRTA, and make it practical and applicable in many fields, such as material science, nuclear engineering, and arms control.

   ↳ physics.ins-detnucl-exphysics.soc-phPhys.Rev.Applied(2021)·5 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.