[en] The analysis of low-level or dominant background dominant radioactiviy is complicated by the fact that sample net rate of activity above background may be negative, because of random fluctuations. (authors)

[en] Background radiation in the open air was measured on behalf of the Ministry of Health and Environmental Protection. The measurements were carried out from the Atominstitut (Technical University) Vienna in all Austrian communities with more than 3000 inhabitants with a modified Geiger-Mueller tube. The results were presented in the form of a map. (R.N.)

[en] This report contains results of dose rate measurements carried out during 1990 at the site of the Dutch National Institute for Public Health and Environmental Protection (RIVM). The dose rates were determined by means of thermoluminescence dosimeters on 12 locations. One of these locations was meant for determination of the natural background (reference) on the site. The dose rates averaged over a year appeared not to deviate significantly from the natural background levels in the Netherlands. The small increase of the annual mean of the dose rate near the building Sg, with regard to the reference level, is due to irradiation activities for calibration work and the replacement of the old ⁶⁰Co-source by a new one in July 1990 with a higher activity. (author). 8 refs.; 4 figs.; 2 tabs

No abstract available

[en] Published in summary form only

[en] The background radiation fluctuations due to scalar type cosmological perturbations are calculated using relativistic potential gauge. The observational upper limit of the quadrupole anisotropy of the background radiation restricts the characteristic scale of perturbations which are larger than the transparency region. The sizes of perturbations with amplitude of the order of unity must be at least forty five times as large as the observational horizon

[en] We present new theoretical estimates of the relative contributions of unresolved blazars and star-forming galaxies to the extragalactic γ-ray background (EGB) and discuss constraints on the contributions from alternative mechanisms such as dark matter annihilation and truly diffuse γ-ray production. We find that the Fermi source count data do not rule out a scenario in which the EGB is dominated by emission from unresolved blazars, though unresolved star-forming galaxies may also contribute significantly to the background, within order-of-magnitude uncertainties. In addition, we find that the spectrum of the unresolved star-forming galaxy contribution cannot explain the EGB spectrum found by EGRET at energies between 50 and 200 MeV, whereas the spectrum of unresolved flat spectrum radio quasars, when accounting for the energy-dependent effects of source confusion, could be consistent with the combined spectrum of the low-energy EGRET EGB measurements and the Fermi-Large Area Telescope EGB measurements.

[en] Abstract only

[en] Conversion coefficients to obtain ambient dose equivalent from air kerma and effective dose equivalent from whole-body dose equivalent are presented for the natural background radiation levels in India reported earlier. (author)

No abstract available