The influence of repeated 0.5 Gy whole-body gamma-ray irradiation on tumour metastasis was examined from the standpoint of tumour invasion in the B16 melanoma pulmonary metastasis model in mice. We confirmed that 0.5 Gy whole-body gamma-ray irradiation (four doses over two weeks) significantly suppressed colony formation in the lungs. In the lung tissue 24 h after irradiation, both the level of ...
Four Cs, namely colour, clarity, carat (weight) and cut, primarily determine the price of a gem. Neutron irradiation, gamma rays and electron beams can be used to enhance the colour and clarity of aquamarine, quartz, tourmaline, kunzite, topaz, pearls and, most importantly, diamonds. Imparting colour and clarity to these gems that are otherwise devoid of these attributes results in significant ...
The incoherent scattering of 661.6 keV gamma rays in a wide range of atomic numbers was studied for 6C, 13Al, 26Fe, 29Cu, 47Ag, 48Cd and 82Pb. It was shown that for heavy elements, the scattering on binding electrons is important. Meanwhile, for light elements, the scattering on free electrons is prominent. The differential Compton scattering cross-section as well as the incoherent scattering ...
An approach for the analysis of gamma ray incoherent scattering on free and binding electrons is presented for Non-destructive Testing (NDT). The method is based on computational simulation and backscattering gamma ray measurements for carbon steel walls. The results of thickness measurements for steel walls are described by the theory of the energy transfer model.Keywords: gamma ray incoherent ...
The use of gamma radiation equipment for the nondestructive measurement of soil density originated nearly four decades ago. The typical procedure involves a careful calibration of the gamma radiation counts on specimens of known density of the same materials as those whose density are to be measured. This paper presents the results of laboratory gamma-ray density measurements on 100-mm-diameter ...
The presence of agents that prevent repair of DNA breaks caused by irradiation can induce more breaks than not. Cadmium is a factor that may cause DNA damage and also inactivate repair enzymes. This paper describes the investigation of chromosomal aberrations induced in human lymphocytes by the combined action of cadmium and gamma rays. Four groups were investigated: Cd alone, gamma radiation ...
In many spectroscopic and photonics applications, it is desirable to work with light that has been polarized in a particular direction. In this article we explore what polarization is, and how it may be obtained from an unpolarized light source. Electro-magnetic radiation (light) What we generally refer to as “light” is more correctly known as 'electromagnetic radiation' (often ...
The natural radiation levels were measured in about 50 residential houses of Tehri Garhwal, Uttaranchal, using an environmental radiation dosimeter in both the indoor and the outdoor atmosphere. The total gamma ray activity was found to vary from 29.74 µR/h to 41.19 µR/h with a mean of 36.5 µR/h for the indoor environment, whereas for outdoors it varied from 28.76 µR/h to 43.46 µR/h with a mean ...
The heat and moisture transfer characteristics of a silt from the Mackenzie River Valley have been determined in a laboratory investigation. A dual gamma-ray scanner was used to measure the changes in density and volumetric moisture content along the soil samples. The coefficients of soil-water diffusivity under isothermal conditions and under temperature gradients have been obtained. The ...
The lichens play an important role in decomposition of the rocky substrate, through the chemical weathering of their substances. In this paper, we wanted to determine the influence of gamma rays on usnic acid production by Cladonia substellata. Samples of lichens were exposed to gamma rays from a Co-60 source, receiving different doses on gamma irradiator. After irradiation, the lichens were ...
The optical properties of CR-39 polymer track detectors irradiated with high Linear Energy Transfer (LET) (alpha particles at energies 3.05 MeV and 4.86 MeV) and followed by low LET (gamma ray irradiation at different doses ranging from 0 to 200 kGy) were investigated. The chemical etching was verified for all samples. Also, the optical properties were studied with an Ultraviolet-Visible (UV-VIS) ...
Nanoparticles of a BaSO4:Eu phosphor with a particle size of around 40 nm have been irradiated by 48 MeV 7Li3+, 75 MeV C6+ and 90 MeV O7+ ion beams at the fluence range of 1 ∼ l09–1 ∼ 1013 ions/cm2. The thermoluminescence (TL) glow curves of the irradiated samples were recorded and studied. The microcrystalline form of this sample is included in the study with the aim of reporting a comparative ...
In a recent article of Dadi and Müller the modification of nuclear photoeffect due to intense laser field is discussed. The paper is criticised from the point of view of gauge invariance. The S–matrix element and the cross–section of the laser–assisted nuclear photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The ...
Radioactive, nuclear, or radiation clean-up is considered as the most dangerous, difficult, and costly remediation activity after a nuclear disaster or accident. The contamination may be found in the air, water, and soil, as wells as equipment and buildings (USEPA, 2010). Radioactive material is unstable, while the nuclei of radioactive atoms emit ionizing radiation (i.e., alpha particles, ...
Photographic emulsion is irradiated under gamma rays irradiation of 137Cs in the IAEA/WHO secondary standard dosimetry laboratory. Dose-response of the film is established. The sensitivity of the film is determined. The dose-rate effect is studied and discussed.Keywords: gamma irradiation, photographic emulsions, dose response, energy transfer model, low ...
Gamma ray build–up factors of concrete shielding have been investigated by Geometrical Progression fitting formula for photon energy range 0.01–15 MeV up to 40 mfp penetration depth. The energy absorption build–up factors and Exposure Build–Up Factor (EBF) of concrete shielding have been studied as a function of photon energy, penetration depth, concrete density and chemical element compositions. ...
The use of uranium-tipped antitank shells during the Iraq war (2003) caused serious concerns in Iran and the international media over possible contamination of the Iranian environment and consequent long-term health effects. After a shell explosion, uranium is discharged by fire into the air in the form of oxidised particles, which can be dispersed over a radius of several kilometres. Gamma ray ...
Radioactive, nuclear, or radiation clean-up is considered the most dangerous, difficult, and costly remediation activity after a nuclear disaster or accident. The contamination may be found in the air, water, and soil, as wells as equipment and buildings (USEPA, 2010).Radioactive material, unlike most matter, is inherently unstable. Over time, the nuclei of radioactive atoms emit what's known as ...
The first few measurements for low level gamma ray spectrometry for the delineation of U and Th along South Purulia Shear Zone (SPSZ) are reported. Estimation of 238U, 232Th and 40K concentrations in widely dispersed rock and soil samples around SPSZ has been undertaken using HPGe detector having relative efficiency of 50%. The maximum concentration among all the samples studied is observed in ...
The optical properties of CR-39 polymer track detectors irradiated with high Linear Energy Transfer (LET) (alpha particles at energies 3.05 MeV and 4.86 MeV) and followed by low LET (gamma ray irradiation at different doses ranging from 0 to 200 kGy) were investigated. The chemical etching was verified for all samples. Also, the optical properties were studied with an Ultraviolet-Visible (UV-VIS) ...