A 3 kJ plasma focus device was used to study the influence of the soft X-ray on live microorganisms. When Saccharomyces cerevisiae – (yeast) was treated with a dose of 65 mSv of the X-ray radiation (14 shots), no difference in the fertility activity between the control probe and the sample was observed. Also no change in the survival enzyme activity was found after irradiation through a 100 μm Al foil of another type of yeast – Kluyveromyces marxiamus. The irradiation of the Chlamydomonas reinhardtii samples by the PF-X-ray emission through 20 μm Al foil with a dose of 11 mSv produces a considerable change of the photosynthesis parameters. This result is similar to the results of previous studies with plasma focus radiation where strong effects were derived with low doses but with a high dose power.

Onboard aircraft exposure to cosmic radiation has been monitored during the period May-December 2005. Mobile Dosimetry Unit (MDU) Si-spectrodosimeter has been used as an active measuring equipment, it has been installed onboard of an A310-300 aircraft. Some passive detectors were placed on the body of MDU. Three types of thermoluminescent detectors (TLD) were used as well as track etch detectors (TEDs). TEDs were treated both as a neutron dosimeter and as a spectrometer of linear energy transfer. Available navigation data permitted us also to calculate onboard exposure during more than 400 individual flights. MDU established and calculated data for each individual flight are compared and analyzed, from the data conclusions as to aircrew exposure are outlined. Particular attention is devoted to the influence of:geomagnetic characteristics and flight altitude on the calculated and MDU-Liulin measured dosimetry characteristic of onboard radiation field;some solar events (Forbush decreases) registered by MDU-Liulin on the level of aircraft crew exposure during monitoring period.Integral data on the exposure due to non-neutron and neutron-like component obtained on the base of MDU and calculated data are compared with the data obtained by TLDs and TEDs, respectively. Total effective dose during the period mentioned (494 flights and 2940 It between taking offs and landings) was found to be about 11-12 mSv for. Results obtained by means of different approaches are analyzed and discussed, it was found that in general good agreement of all data sets could be stated. (c) 2006 COSPAR. Published by Elsevier Ltd. All rights reserved.

Track etch detectors are extensively used for Rn measurement in the environment because of their excellent ability to detect heavy charged particles. However, sometimes their application requires additional equipment and evaluation without automatic image analyzer can be time consuming. Moreover, due to track overlapping, track detectors are best suited for relatively low Rn concentrations. Thermoluminescent detectors (TLDs) are routinely used for detection of β and γ radiation, and in some cases they can be successfully used to measure other kinds of radiation, e.g. neutrons and α. In this study we compare the performance of TLDs and track detectors during field measurement of soil gas Rn concentration. A specially designed detector holder determines the irradiation geometry and contains either CR-39 track detectors or two sets of several (6–14) TLDs. The first set of TLDs (bare) detects both α and γ and the second set is hermetically sealed and detects γ radiation only. The response of two kinds of Bulgarian thermoluminescent materials, CaSO4:Dy and a CaSO4:Dy/graphite mixture was compared to the response of reference track detectors. Measurements were carried out at three distinct sites with different Rn concentration and two types of detector sealing were tested. The obtained results suggest that TLDs can successfully be used to measure medium or higher (>50kBqm−3) soil gas Rn concentrations. Compared to track detectors TLDs extend the upper limit of detection by as much as two orders of magnitude.

New thermoluminescent detectors (TLDs) were prepared from mixtures of CaSO4:Dy powder with graphite. The concentration of graphite varied from 0.5 to 20% by weight. The response of these mixed detectors to gamma radiation and to some beta radiation was studied, using Pm-147, Tl-204, and (Sr-90/Y) as radiation sources.It was found that the relative beta response of graphite-containing detectors increases, relative to the Co-60 response, with increasing graphite content.Results obtained are discussed and analysed from the points of view of beta radiation detection and dosimetry. Some remarks on the problem gamma-X-beta mixed field dosimetry are also given.

Recently we prepared thermoluminescents detectors from mixtures of some phosphors with graphite or B 4 C in different concentrations and grain sizes. When used in mixed neutron-gramma-beta fields, their reading is also influenced by their sensitivity to neutrons. To understand this influence, their relative responses to neutrons have to be known. The results are presented of studies in which the relative responses of some newly prepared detectors to fast neutrons generated at the U120 cyclotron (E N ∼7 MeV) or at the J15 generator (E N ∼14.7 MeV) have been established. Results obtained are analysed and compared with previous data for comparable and other types of thermoluminescent detectors

The responses of recently developed polyethylene embedded thermoluminescent detectors, TLDs, to neutrons from the polyenergetic sources 252Cf, PuBe and 9Be(d,n) with EN = 7.2 MeV were studied. The TL materials CaSO4:Dy, CaSO4:Mn and Al2O3 were used. The influence of an external proton radiator (polyethylene cover) on the relative response was also studied. It was found that relative responses increased substantially with both internal and external proton radiators. The enhancement depends not only on the neutron energy but also on the type of TLD. The results obtained are analysed and discussed.

This work describes the influence of polyethylene radiators on fast neutron relative responses of some thermoluminescent detectors. The studies concentrated mostly on the influence of an international radiator, i.e. mixed inorganic phosphor-polyethylene detectors. The procedure used to prepare such detectors using sufficiently thermally stable polyethylene is described. The reproducibility of such mixed detectors, and the possibilities of re-use and other practical aspects are discussed. Neutron relative responses of such mixed detectors having CaSO4:Dy, CaSO4:Mn, and Al2O3 as thermoluminescent materials were measured in a reactor beam, as well as for 14.7 MeV neutrons. It was found that relative responses increase substantially for the internal polyethylene radiator. For high energy neutrons the response can be increased even more by using an additional external polyethylene radiator. The results obtained are analysed and discussed.

In the composition of the type-K emulsion used in personnel neutron dosimetry, nitrogen [5] appears along with other elements. Through the action of thermal neutrons, the reaction Nt4(n, p)C 14 takes place in the emulsion with the emission of protons having an energy in the neighborhood of 6 MeV. The range of these protons in the emulsion is approximately 6t~. The number of protons, N(E), created per cm 2 of emulsion during its irradiation by neutrons with an energy E can be determined from N (E) = ~p (E) ~ (E) A,