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The gamma ray, neutron, and electron radiation interaction parameters were calculated for some topological insulating (TI) materials such as Sb2Te3, Bi2Se3, Bi2Te2Se and Bi2Te3 at various energies. The gamma ray interaction parameters such as mass attenuation coefficient, half value layer, tenth value layer, effective atomic number, equivalent atomic number, exposure buildup factor, and energy absorption buildup factor were calculated in the energy range of 0.015–15 MeV at penetration depths of 1–40 mfp by using the five-parameter Geometric Progression (G-P) fitting approximation method. The buildup factors were found to be dependent on the energy of the incident photon, penetration depth, and material elemental composition, and they were also found to be higher for Sb2Te3 than for other TI materials throughout the energy region of investigation. The neutron interaction parameters, such as fast neutron removal cross section, were calculated for the selected topological insulator materials using Phy-X/PSD software and found to be higher for Bi2Te3 than for the other three materials. The electron stopping power values were calculated for the selected topological insulator materials in the energy range of 0.01 MeV to 1000 MeV using the ESTAR program. It was found that the stopping power values decreased slowly with increasing electron energy in the lower energy region, remained almost constant in the medium energy region, and increased rapidly in the higher energy region. [ABSTRACT FROM AUTHOR]

The nuclear radius parameter of carbon, aluminium, iron, copper, and zinc nuclei has been determined by using (n, γ)-reaction. The neutrons from the americium-beryllium source are made to interact with the water moderator to produce the γ-rays of 2.2 MeV through (n, γ)-reaction. The γ-radiation emitted from the water medium is measured with a scintillation detector coupled to 8k multi-channel analyzer. The neutrons from the americium-beryllium source are allowed to transmit through carbon, aluminium, iron, copper, and zinc elemental targets of various thicknesses, and transmitted neutrons are again allowed to interact with water moderator to produce 2.2 MeV γ-radiation. By measuring the yield of γ-radiation produced in water moderator by neutrons transmitted through elemental targets of different mass number values, the total neutron interaction cross-sections are determined. By knowing the total neutron interaction cross-sections and mass number of the target nuclei, the radius parameter has been determined. [ABSTRACT FROM AUTHOR]

The L1, L2 and L3 subshells of Hf, Ta and Re atoms have been excited selectively by using microprobe XRF beam line, Indus‐2, RRCAT, India. The consequent characteristic L X‐ray photons, emitted from the targets due to creations of vacancies in L subshells, are measured using silicon drift detector (X‐123) spectrometer. As the energy of synchrotron radiation increases, the contribution of characteristic L X‐ray intensity increases. The advantage of the increase in the intensity of the characteristic L X‐ray photons with an increase in the energy of synchrotron radiation has been used to determine the L subshell fluorescence yield ratios of Hf, Ta and Re atoms by adopting the selective excitation method. The measured ratios of L subshell fluorescence yield have been compared with theoretical and other experimental values. [ABSTRACT FROM AUTHOR]

Measurements of cross sections of evaporation residue (ER) and spin distributions of heavy nuclei, produced via compound nuclear fusion-evaporation reactions, provide crucial information about the dynamics of nuclear fission and the survival probability of the system against fission. Such measurements help in probing the evolution of the compound system from equilibrium to the saddle and the underlying role of nuclear dissipation in hindering fission. The purpose of the present measurements is to understand the survival probability of the 224Th* compound nucleus against fission and its dependence on angular momentum. Measurements of the ER cross sections and spin distributions have been carried out for the 16O+208Pb and 18O+206Pb reactions which form the same 224Th* compound nucleus. The two reactions have been carried out at laboratory energies ranging from 87 MeV to 122.6 MeV and 85.7 MeV to 121.4 MeV, respectively. The measurements have been performed at Inter University Accelerator Centre, New Delhi using the Hybrid Recoil mass Analyzer in gas-filled mode, coupled with the 4π spin spectrometer of Tata Institute of Fundamental Research. The reduced ER cross sections (σER/πRB²) for both systems are comparable at low excitation energies while at higher excitation energies the 18O+206Pb system shows nearly 50% higher values. However, the 18O+206Pb system shows lower mean γ ray multiplicity (and hence lower mean angular momentum) at all excitation energies which is a surprising result. [ABSTRACT FROM AUTHOR]

Evaporation residue cross sections are measured for the reaction 48Ti+138Ba which forms the compound nucleus 186Pt*. The cross sections are measured at beam energies in the range of 189.3-234.4 MeV. The experimental evaporation residue cross sections are compared with the dynamical model which employs one-dimensional Langevin dynamical calculations. The dissipation strength of the Langevin equation is calculated using both chaos weighted wall formula and a constant reduced dissipation function. The measured ER cross sections are found to be much less than the theoretical predictions. Further, the measured ER cross sections for the system 48Ti+138Ba are compared with those of 32S+154Sm forming the same compound nucleus. The suppression in the evaporation residue cross sections of the former reaction may be attributed to the increasing competition from quasifission. The quasifission reaction is found to have superseded any effect of neutron shell closure (N=82) of the target in the present study. [ABSTRACT FROM AUTHOR]

Evaporation residue cross sections for the 16O + 203,205Tl reactions were measured at laboratory beam energies in the range of 82-113 MeV using a gas-filled separator. Transmission efficiency of the separator was estimated using a calibration reaction 16O + 197Au and by simulating the evaporation residues angular distributions. Statistical model calculations were performed for both the measured systems. These calculations overestimate the experimental evaporation residue cross sections. This could be attributed to the presence of noncompound nuclear fission. An estimation of noncompound nuclear fission contribution was carried out. Comparison with neighboring systems shows that a slight change in the entrance channel or the compound nucleus properties makes a large difference in evaporation residue cross sections. [ABSTRACT FROM AUTHOR]

Neutron multiplicity excitation function has been measured for the 30Si+197Au reaction populating the 227Np compound nucleus at excitation energies in the range 44.1-78.8 MeV using the National Array of Neutron Detector facility of Inter University Accelerator Centre, New Delhi. Measured pre-scission neutron multiplicity values are analyzed using a statistical model incorporating Krammer's fission width due to the dissipative drag in nuclear fission, shell corrections in fission barrier and level density, collective enhancement of level density, and K-orientation effect. The present work demonstrates that a strong fission hindrance is essential to reproduce the experimental pre-scission neutrons, whereas the temperature dependent dissipation coefficient as observed in a few recent measurements is not required to reproduce the experimental νpre data. No substantial effect of collective enhancement of nuclear level density and tilting away effect of compound nucleus spin on neutron emission prior to the scission configuration was observed unlike fission of preactinides. [ABSTRACT FROM AUTHOR]

Background: A significant research effort is currently aimed at understanding the synthesis of heavy elements. For this purpose, heavy ion induced fusion reactions are used and various experimental observations have indicated the influence of shell and deformation effects in the compound nucleus (CN) formation. There is a need to understand these two effects. Purpose: To investigate the effect of proton shell closure and deformation through the comparison of evaporation residue (ER) cross sections for the systems involving heavy compound nuclei around the ZCN=82 region. Methods: A systematic study of ER cross-section measurements was carried out for the 48Ti+142,150Nd, 144Sm systems in the energy range of 140-205MeV. The measurement has been performed using the gas-filled mode of the hybrid recoil mass analyzer present at the Inter University Accelerator Centre (IUAC), New Delhi. Theoretical calculations based on a statistical model were carried out incorporating an adjustable barrier scaling factor to fit the experimental ER cross section. Coupled-channel calculations were also performed using the ccfull code to obtain the spin distribution of the CN, which was used as an input in the calculations. Results: Experimental ER cross sections for 48Ti+142,150Nd were found to be considerably smaller than the statistical model predictions whereas experimental and statistical model predictions for 48Ti+144Sm were of comparable magnitudes. Conclusion: Though comparison of experimental ER cross sections with statistical model predictions indicate considerable non-compound-nuclear processes for 48Ti+142,150Nd reactions, no such evidence is found for the 48Ti+144Sm system. Further investigations are required to understand the difference in fusion probabilities of 48Ti+142Nd and 48Ti+144Sm systems. [ABSTRACT FROM AUTHOR]

Background: Formation of the compound nucleus (CN) is highly suppressed by quasifission in heavy-ion collisions involving massive nuclei. Though considerable progress has been made in the understanding of fusion-fission and quasifission, the exact dependence of fusion probability on various entrance channel variables is not completely clear, which is very important for the synthesis of new heavy and superheavy elements. Purpose: To study the interplay between fusion and quasifission in reactions forming CN in the boundary region where the fusion probability starts to deviate from unity. Methods: Fusion evaporation residue cross sections were measured for the 28,30Si+180Hf reactions using the Hybrid Recoil Mass Analyser at IUAC, New Delhi. Experimental data were compared with data from other reactions forming the same CN or isotopes of the CN. Theoretical calculations were performed using the dinuclear system and statistical models. Results: Reduced evaporation residue cross sections were observed for the reactions studied compared with the asymmetric reaction forming the same CN, indicating fusion suppression in more symmetric systems. The observations are consistent with fission fragment measurements performed in the same or similar systems. Larger ER cross sections are observed with increase in mass in the isotopic chain of the CN. Conclusions: Fusion probability varies significantly with the entrance channels in reactions forming the same CN. While complete fusion occurs for the 16O+194Pt reaction, the fusion probability drops to approximately 60-70% for the 30Si+180Hf and less than 20% for the 50Ti+160Gd reactions, respectively, forming the same CN at similar excitation energies. [ABSTRACT FROM AUTHOR]

This experimental investigation focuses on the gamma-ray interaction parameters and the buildup factor in lanthanide compounds (CeO 2 , Ce(SO 4 ) 2 , Dy 2 (SO 4 ) 3 , C 3 O 9 Sm 2 , C 3 Gd 2 O 9 , Pr 2 O 3 ). These compounds were exposed to weak radioactive gamma sources with energies of 356, 511, 662, 1173, 1275, and 1332 keV by adopting narrow and broad beam geometry experimental arrangements. The incident and transmitted radiation intensities were measured using a NaI (Tl) detector. Experimentally measured values of mass attenuation coefficient and effective atomic number of lanthanide compounds were found to be in precise agreement with theoretical values obtained from NIST XCOM and Direct-Z eff database respectively. Additionally, the experimentally determined buildup factor values were compared with energy absorption buildup factor (EABF) and exposure buildup factor (EBF) values obtained from Phy-X/PSD software, providing insights into the gamma-ray penetration depth in terms of mean free path (MFP). At 356 keV, the EABF analysis showed that most compounds had a penetration depth of around 8 mean free paths. In contrast, the EBF analysis indicated penetration depths exceeding 10 mean free paths for all compounds except Ce (SO 4 ) 2 . This new approach holds immense potential for transformative advancements in medical diagnostics, therapy, and the development of innovative technologies in nuclear sciences., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Aravind S. Bennal reports financial support was provided by University Grants Commission Department of Atomic Energy Consortium for Scientific Research. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This experimental approach was designed to understand the gamma interaction parameters for the essential biomolecules, including starch soluble, cholesterol, myristic acid, glucose, oxalic acid, dextrose, salicylic acid, ethyl cellulose and sucrose. The empirical determination of gamma interaction parameters, such as interaction mean-free-path (MFP), buildup factor, and effective atomic number (Z eff ) was performed by measuring mass attenuation coefficient (μ/ρ) at energies of 356 keV, 511 keV, 662 keV, 1173 keV, 1275 keV and 1332 keV. This was achieved using weak radioactive sources and a NaI(Tl) scintillation spectrometer with collimated and non-collimated transmission geometry. The experimentally determined values of gamma-ray interaction parameters were obtained non-destructively and precisely agreeing with the expected values from simulations and codes. In addition, the research findings also revealed a novel trend in gamma interaction mean free path as a function of energy and variable buildup factors for the selected biomolecules. These research findings provide valuable insight into the process of gamma radiation interaction. This approach may fulfil the increasing demand of medical, technical and academic research laboratories for a cost-effective and reliable empirical methodology to understand gamma radiation interaction with matter., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Dr.A.S.Bennal reports equipment, drugs, or supplies was provided by Karnatak University Dharwad. Dr.A.S.Bennal reports a relationship with Karnatak University Dharwad that includes: employment., (Copyright © 2023 Elsevier Ltd. All rights reserved.)