Selim Pašić

Measurement of the component of the Ge-detector response function due to escape of secondary radiation

Abstract A method of measuring the component of the detector response function due to the escape of secondary photons and electrons from the detector active volume has been investigated. It is based on the use of two detectors that operate in coincidence. The requirement of simultaneity of recorded events in the detectors and the condition of constant energy sum eliminate almost entirely all other components of the detector response function. Results of a measurement of the escape of photons from the active volume of a Ge-detector into the solid angle of about 0.11 sr at the incident energy of 59.537 keV are given. A very clear spectrum was obtained. The results of the calculations considering all relevant single-and double-scattering processes are in good agreement on the absolute scale with the experimental values. The calculations were extended to the entire solid angle for the escape of secondary radiation of 2π.

Acute whole-body low dose gamma irradiation does not affect humoral immunity in chicken

It has been documented that low-dose ionizing irradiation enhanced the immune response on both cellular and humoral immunity in mammals. In the present study three experiments were conducted to compare antibody titer against vaccinal strain of Newcastle disease virus after low-dose total body gamma irradiation in chickens. In all experiments, male Leghorn chicks were irradiated, on day 1 or 3 of life, with the dose of 0.05, 0.15, 0.30, 0.50 and 0.80 Gy gamma radiation. In two experiments, after irradiation, chicks were vaccinated with the commercial Newcastle disease vaccine by the nebulisation method. Blood samples were collected for serological analyses from day one or 7 up to day 28 in weekly interval, depending on experimental design. Specific serum anti- Newcastle disease virus antibodies were quantitated by hemagglutination inhibition assay. No significant effect on the level of hemagglutination inhibition maternal antibody titer and antibody titer against vaccinal Newcastle disease virus strain as well as on the antibody rate catabolism was found. The ionizing radiation used in the present experiment did not influence the humoral immune response in this light strain of chickens.