120377524
Measurement of neutron multiplicity from fission of {sup 228}U and nuclear dissipation
Pre- and post-scission neutron multiplicities are measured at different excitation energies of the compound nucleus {sup 228}U populated using the {sup 19}F+{sup 209}Bi reaction. The measured yield of pre-scission and total neutrons are compared with the statistical model calculation for the decay of a compound nucleus. The statistical model calculations are performed using the Bohr-Wheeler transition state fission width as well as the dissipative dynamical fission width due to Kramers. Comparison between the measured and the calculated values shows that, while the Bohr-Wheeler fission width grossly underestimates the pre-scission neutron yield, a large amount of dissipation is required in the Kramers width to fit the experimental pre-scission multiplicities. Various factors contributing to the large excitation energy dependence of the fitted values of the dissipation coefficient are discussed.
37575993
Coulomb excitation studies in antimony isotopes.
Various low-lying energy levels up to 1.145 MeV in {sup 121,123}Sb have been Coulomb excited using 3.0--4.0 MeV proton-beam energies. The reduced transition probabilities of the excited levels have been newly deduced from the measured yields of the deexcitation gamma rays. The values of mixing ratios for a few transitions and the removal of ambiguities in the spin values of some levels have been presented from the angular distribution analysis.
122194176
Search for entrance channel effects in heavy ion induced fusion reactions via neutron evaporation
26795671
Coulomb excitation of cadmium isotopes with protons.
Low-lying positive parity levels of the isotopes in natural cadmium were Coulomb excited with 2.7--4.2 MeV protons. Eight levels of /sup 111/Cd up to 1130.4 keV and four levels of /sup 113/Cd up to 680.5 keV excitation energy, and the first 2/sup +/ states in even-even isotopes (/sup 110,112,114,116/Cd) were excited. A 50 cm/sup 3/ Ge(Li) detector was used to measure the deexcitation gamma-ray yields. The 1130.4 keV level in /sup 111/Cd had not been investigated earlier through Coulomb excitation. Also the 245.4, 700, 754.9, 855.6, and 1020.7 keV levels in /sup 111/Cd, and the 316.1 keV level in /sup 113/Cd were Coulomb excited with protons for the first time. The reduced E2 transition probabilities B(E2), and partial half-lives T/sub 1/2/ (E2), for various levels were determined. The gamma-ray angular distributions were analyzed to deduce the E2/M1 mixing ratios (delta) for various transitions from the levels in /sup 111,113/Cd. The 700, 754.9, 855.6, and 1020.7 keV levels in /sup 111/Cd, and the 680.5 keV level in /sup 113/Cd have been assigned a spin value of (3/2)/sup +/, while the 1130.4 keV level in /sup 111/Cd has been assigned a spin of (5/2)/sup +/. The results have been compared with existingmore » theoretical and experimental data in the literature.« less
120945477
On improvement of charge resolution of cosmic ray particles using a cellulose nitrate plastic detector
Abstract By employing improved procedures of measurement and analysis we have been able to obtain good charge resolution for stopping cosmic ray nuclei with Z ⩽30 in a cellulose nitrate detector. In a particular, it has been found that ( V t V b ) provides a much more reliable measure of ionisation loss than cone length. A charge resolution of 0.2 charge units for nuclei with Z ≲20 and of 0.3 charge units for nuclei with Z > 20 has been achieved in the present experiment.
120052850
Search for entrance channel effects in heavy ion induced fusion reactions through the compound system79Rb
118545913
Higher Dimensional Cosmological Model With Gravitational and Cosmological "Constants"
In this paper we have considered a cosmological model representing a flat viscous universe with variable G and Λ in the context of higher dimensional spacetime. It has been observed that in this model the particle horizon exists and the cosmological term varies as inverse square of time. The deceleration parameter and temperature are well within the observational limits. The model indicates matter and entropy generation in the early stages of the universe. Further, it is shown that our model generates all models obtained by Arbab and Singh et al. in four-dimensional space-time.
115886900
Cosmological models with a variable Lambda term in higher dimensional spacetime
120176685
Intermittency and multiplicity moments of charged particles produced in 32S–Ag/Br interaction at 200 A GeV/c
The nature of nonstatistical fluctuations in the density distribution of singly charged particles produced in 32S–Ag/Br interactions at an incident momentum of 200 A GeV/c has been investigated. With the help of the nuclear photographic emulsion technique, the data were collected, and using different statistical methods of multiplicity moments these data have been analysed in terms of intermittency and fractal properties of one- and two-dimensional phase space distributions. Wherever possible, experimental results have been compared with the results obtained in other similar heavy-ion-induced experiments, as well as with those obtained from simulated events of the Lund Monte Carlo code FRITIOF. In some cases events simulated by generating (pseudo)random numbers have also been used for the purpose of comparison. The investigation shows the presence of weak intermittency in one dimension (1D) that is consistent with self-similarity in the density distribution. In two dimensions (2D), anisotropy in the distributions along longitudinal and transverse phase space variables indicates that self-affinity, rather than self-similarity in the distributions, is responsible for the observed behaviour. From the analysis of factorial correlators and oscillatory multiplicity moments, the presence of a few-particle short-range correlation has also been established. In almost all cases, the simulated interactions fail to replicate the experimental results.
122378029
Bianchi type I bulk viscous cosmological models with particle creation in Brans-Dicke theory
This paper is devoted to the study of the role of particle creation and bulk viscosity in the evolution of the homogeneous and anisotropic model of the universe represented by Bianchi type I space-time metric in Brans-Dicke theory. Particle creation and bulk viscosity have been considered as separated irreversible processes. In order to discuss the physical and geometrical behaviour of the model, a new set of exact solutions of field equations have been obtained in non-causal, truncated and full causal theories. The dynamical behaviours of models have also been discussed.
121441857
Centrality dependence of nonstatistical fluctuation in single particle density distribution in S-32-Ag/Br interaction at 200A-GeV/c
Nonstatistical fluctuations in the density distribution of shower tracks coming out of 32S–Ag/Br interaction at an incident momentum of 200A GeV/c, have been characterized by using the intermittency and multifractality techniques. A sample of 32S–Ag/Br nuclear emulsion events has been partitioned into three subsamples with respect to the shower track multiplicity in such a way that one can roughly estimate the average centrality for each subsample. Thereby, the centrality dependence of a set of relevant intermittency and multifractal issues has been investigated.