Thermoluminescent dose measurements on-board Salyut type orbital stations.

A small, vibration- and shock-resistant thermoluminescent dosemeter /TLD/ system--named PILLE--was developed at the Health Physics Department of the Central Research Institute for Physics, Budapest, to measure the cosmic radiation dose on board orbital stations. The first on-board measurements with this system were performed /by B. Farkas, the Hungarian astronaut/, on the Salyut-6 space station in 1980. The same instrument was used by other crews in the following years. Doses measured at different sites in Salyut-6 are presented. The dose rates varied from 0.07 to 0.11 mGy.day-1. After the first cosmic measurements, the system was further developed. The minimum detectable dose of the new TLD system is 1 microGy, i.e. less by on order of magnitude than that of the former system. The self-irradiation dose rate of the TLD bulbs is also reduced--by more than one order of magnitude--to 10 nGy.h-1, by the use of potassium-free glass for the bulb envelope. This new type of PILLE TLD system is currently on-board Salyut-7. The dose rates /0.12-0.23 mGy.day-1/ measured in 1983 are presented in detail.

Depth-dose distribution measurements and calculations in an elliptical phantom.

Calculations and measurements are presented for the dose distribution in a water-filled elliptical phantom when the phantom was irradiated with neutrons from two different, unshielded light-water moderated reactors. The calculations were performed by a Monte Carlo code; for the measurements we used activation, TL and solid-state nuclear track detectors. We observed that the neutron spectra do not vary significantly inside the phantom and that not only the total absorbed dose but also the kerma value at a depth of approximately 2 cm can be higher than that on the front (in our case, by a factor of about 1.2). The measurements and calculations resulted in a kerma attenuation from the front to the back of the phantom a factor of about 5, less than was previously known through the literature.

A new thermoluminescent dosimeter system for space research.

A small, portable, vibration and shock resistant thermoluminescent dosimeter system was developed to measure cosmic radiation dose on board a spacecraft. The system consists of a small battery-operated reader and a special bulb dosimeter. Doses from 10 microGy up to 100 mGy can be measured. The electrical power consumption of the reader is about 5 W, its volume is about 1 dm3 and its mass is about 1 kg. Details are given for the construction and technical parameters of the dosimeter and reader.

Results of cosmic radiation dose field measurements aboard the "Salyut-6" orbital station.

During the 3rd main expedition on board the "Salyut-6" orbital station in 1979 the integral characteristics of cosmic radiation were measured in various positions inside the manned modules (experiment "Integral"). Measurements were performed with thermoluminescent dosimeters, photographic films and solid state plastic detectors supplied for the experiment by specialists of the USSR, Bulgaria, Hungary, GDR and Romania. The dose gradient inside the manned modules of the station amounted to 70% for long intervals of time. During the experimental period the dose rate inside the station was 15 to 30 mrad per day. The mean flux of particles with Z > or = 6 and LET > or = 200 keV/micrometer was found to be 0.22 cm-2 or day-1.