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The present study aims to investigate the gamma photon-neutron attenuation parameters of the marble concrete such as the linear attenuation coefficient (mu), Mass Attenuation Coefficient (MAC), Half Value Layer (HVL), neutron removal cross-section (Sigma(R)), and Exposure Buildup Factor (EBF) by MCNPX Monte Carlo code to examine the possibility of utilizing selected samples against gamma photon-neutron. The six types of marble concrete were exposed to different energies ranging from 511 to 1332 keV. The shielding effectiveness of the selected marble concrete was compared to each other and the obtained results show that the increment of the penetration depth causes an increase in the value of EBF and the sharp peak is monitored at 200 keV. The Sigma(R) (neutron removal cross-section) values were also reported for all types of marble concrete. The outcomes depict that n-ary sumation (R) is strongly relevant to the weight fractions of light elements of the selected shielding materials. Furthermore, the variations of sigma(a) (total atomic cross-section) were reviewed and discussed versus wide energy ranges. Findings in all sections confirmed that NM-15 has the best gamma photon shielding quality in comparison with the other types of marble concrete, while NM-0 and NM-15 show the highest neutron proficiency.

The backscattered peak and albedos are important for the estimation of exposure distribution and for better understanding the phenomenon of the backscattering of gamma photons. To characterize the backscattering probability of gamma photons interacting with different atomic numbers (Z), number (A N), energy (A E) and dose (A D) albedos are experimentally evaluated. The response function converts the observed pulse-height distribution of a NaI(Tl) scintillation detector to a true photon spectrum. For each of the incident gamma photon energies, the number and energy albedos show an increase with the increasing target thickness, and finally saturate. The energy albedos are found to be decreasing with the increase in the atomic number of the target material and incident gamma photon energy. The dose albedos do not differ significantly from the energy albedos for the chosen incident gamma photon energies.

The collision integral cross sections are obtained and computed for several experimentally realizable cases to understand the various features of the higher-order process known as double photon Compton scattering. The computational work carried out using the Mathematica software package generally corresponds to three different incident gamma photon energies of {sup 137}Cs (661.65 keV), {sup 65}Zn (1.12 MeV), and that from the radiative capture of {sup 19}F (6.14 MeV). The characteristic features revealed a need to be investigated experimentally to check for their support to the currently acceptable theory of this quantum electrodynamics process. An experimental technique has been suggested for the measurement of these collision integral cross sections.

Gamma photon induced modifications in Polyvinylchloride (PVC) polymer have been studied in the dose range of 101-106Gy at room temperature. Polyvinylchloride films have been irradiated with different doses of gamma radiation from a 60Co source. To monitor the chemical and structural changes caused by gamma radiation IR and UV-Vis spectroscopy of pristine and irradiated PVC have been performed and using the spectral data some changes in the properties have been investigated. The spectral studies have indicated that at a dose of 106Gy scissioning of the C-a bonds takes place. This scissioning of the chain initiates decomposition at a lower temperature. Thermal stability of the polymer reduces due to irradiation but the decomposition patterns remain the same. The optical band-gap is found to decrease due to irradiation at doses bigher than 103Gy.

To determine the efficacy of WR-151327 (WR) [S-3-(3-methylaminopropylamino) propylphosphorothioic acid; (CH3-HN-(CH2)3-NH-(CH2)3-S-PO3H2)] in increasing resistance to bacterial infection after a sublethal dose of gamma-photons or mixed-field neutrons plus gamma-photons.B6D2F1/J female mice received 200 mg/kg WR i.p. or saline vehicle 20-30 min before or after sham (0 Gy) or 7.0 Gy 60Co gamma-photon irradiation. WR or saline vehicle was given only before 3.5 Gy TRIGA-reactor-produced mixed-field [n/(n+y) = 0.67] irradiation. Four days after drug treatment or drug treatment and irradiation, graded doses of Klebsiella pneumoniae were injected s.c. into mice, and 30-day survival was recorded. To assess haemopoietic changes other unirradiated and irradiated mice not injected with bacteria were given WR or saline. Peripheral blood (PB) and femoral bone marrow (BM) cells were measured 1, 3 or 4, 7, 10 and 14 or 15 days later.WR pretreatment increased resistance to infection in irradiated but not in unirradiated mice. Bacterial CFU-LD50/30 values for 0 Gy saline-treated mice were 1.20x10(6); for 0 Gy WR-treated mice 1.16x10(6); for gamma-photon-irradiated saline-treated mice 3.02x10(1); for gamma-photon-irradiated WR-treated mice 1.24x10(4); for mixed-field-irradiated saline-treated mice 1.94x10(2); and for mixed-field-irradiated WR-treated mice 6.13x10(3). WR-induced resistance to infection paralleled increased numbers of PB white cells, neutrophils, platelets, femoral BM cells and granulocyte macrophage colony-forming cells (GM-CFC) in irradiated mice not given bacteria.These studies quantify the resistance to bacterial infection in mice treated with WR before sublethal irradiation. The findings suggest that WR treatment increases resistance to infection in immunocompromised hosts.

A novel diagnostic f or ion temperature and density is discussed. The diagnostic, based on the detection of the 24-MeV gamma photon from the D(d,γ)4He fusion reaction, appears feasible in reactor-o...

Measurement and prediction of outside surface exposure rates and measurement of gamma photon spectra from radioactive sources are described. The sources were 30-cm-diam canisters filled with borosilicate glass to a height of {approximately} 100 cm. Each canister contained up to 237 kCi of {sup 137}Cs and 159 kCi of {sup 90}Sr. Exposure rates on the outside surfaces ranged from 26000 to 320000 R/h chiefly from decay of {sup 137}Cs.