Examination of level density prescriptions for the interpretation of high-energyγ-ray spectra

Abstract

High energy γ-ray spectra measured by our group involving the compound nuclei (CN) 63 Cu at excitation energy (E * ) ∼ 36 MeV with average angular momentum (J) = 12 -17h, 97 Tc at E * ∼ 29 -50 MeV with J = 12 -14h, 113 Sb at E * = 109 MeV and 121 MeV with J = 49 -59h and 201 Tl at E * = 39.5, 47.5 MeV with J = 18 -24h have been analyzed utilizing the level density prescriptions of (i)Ignatyuk, Smirenkin and Tishin (IST), (ii)Budtz-Jorgensen and Knitter (BJK), and (iii) Kataria, Ramamurthy and Kapoor (KRK). These three prescriptions have been tested for correct statistical model description of high energy γ-rays in the light of extracting the giant dipole resonance (GDR) parameters at low excitation energy and spin where shell effects might play an important role as well as at high excitation energy where shell effects have melted. Interestingly, only the IST level density prescription could explain the high energy γ-ray spectra with reasonable GDR parameters for all the four nuclei.

General Description of Fission Observables: GEF Model Code

“…However, these calculations are not satisfactory, because the energy-independent leveldensity parameter of Ref. [216] does not consider the well established washing out of shell effects with increasing excitation energy [276]. The level-density prescription implemented in GEF follows the widely used formulae of Ref.…”

Total absorption spectroscopy of the β decay of Zr101,102 and TcDombos1, Spyrou2, Naqvi3 et al. 2021Phys. Rev. C10000View full textAdd to dashboardCite

“…This procedure is repeated for all pseudolevels within the quasicontinuum. Other implementations of the statistical model to create γ -ray cascades can be found in DECAYGEN [56], DEGEN [57], CASCADE [58][59][60][61], γ DEX [62], and RAINIER [63].…”

“…As explained in Sec. IV B, the values reported in this table are from the fit in which the transition from the ground state to the β-decaying isomeric state was held fixed between 60 The half-life of the parent 109 Tc is 0.87( 7) s [43], that of the daughter 109 Ru is 34.4(2) s [81], and that of the charge-state contaminant 106 Tc 42+ is 35.6(6) s [82]. Because the experimental spectra used in the TAS analysis were obtained with a correlation time window of 1 s, the amount of contamination from the decay of the daughter and charge-state contaminant was negligible (less than 3%).…”

Experimental investigation on the temperature dependence of the nuclear level density parameter

“…Along with that, they also provide information about the thermodynamic quantities such as temperature and entropy as well as pairing correlations in the nuclear structure study [2]. The knowledge of nuclear level density is also very crucial while extracting the parameters of the giant dipole resonance built on highly excited states of the nuclei [3,4]. However, the characterization of the nuclear level density (NLD) in the regions of high excitation energy, angular momentum and different nuclear shapes are in large part phenomenological.…”

“…In this work we report on the angular momentum gated neutron evaporation spectra at different excitation energies (30-50 MeV) for the reaction 4 He + 93 Nb. The specific advantage of using light ion reaction is that the major residues are of similar nature and in our case they are 95 Tc, 94 Tc and 93 Tc depending on the excitation energy of the compound nucleus.…”