Evaluation of solid state nuclear track detector stacks exposed on the international space station

Abstract

The aim of the study was to investigate the contribution of secondary neutrons to the total dose inside the International Space Station (ISS). For this purpose solid-state nuclear track detector (SSNTD) stacks were used. Each stack consisted of three CR-39 sheets. The first and second sheets were separated by a Ti plate, and the second and third sheets sandwiched a Lexan polycarbonate foil. The neutron and proton responses of each sheet were studied through MC calculations and experimentally, utilising monoenergetic protons. Seven stacks were exposed in 2001 for 249 days at different locations of the Russian segment 'Zvezda'. The total storage time before and after the exposure onboard was estimated to be seven months. Another eight stacks were exposed at the CERF high-energy neutron field for calibration purposes. The CR-39 detectors were evaluated in four steps: after 2, 6, 12 and 20 h etching in 6 N NaOH at 70 degrees C (VB = 1.34 microm h(-1)). All the individual tracks were investigated and recorded using an image analyser. The stacks provided the averaged neutron ambient dose equivalent (H*) between 200 keV and 20 MeV, and the values varied from 39 to 73 microSv d(-1), depending on the location. The Lexan detectors were used to detect the dose originating from high-charge and high-energy (HZE) particles. These results will be published elsewhere.

Cosmic radiation exposure of biological test systems during the EXPOSE-R mission

“…This high variation is supported by later measurement inside the Russian module performed by DLR resulting in dose variations between 240 and 340 μGy d −1 (Pálfalvi et al . 2014). It is interesting to note, however, that the daily dose measured within the EXPOSE-R experiment is very close to the data given for measurements inside the Russian Segment of the ISS.…”

“…The dose values measured with the TLDs inside EXPOSE-R are very close to dose values measured inside the ISS (Lishnevskii et al 2010; Welton et al 2012; Berger et al 2013; Pálfalvi et al . 2014) and reflect therefore the high amount of shielding of the biological samples located within the EXPOSE-R facility.…”

Differentiating multi-MeV, multi-ion spectra with CR-39 solid-state nuclear track detectors

“…One of these uses is as a solid-state nuclear-track detector (SSNTD). Since its conceptual inception as a particle detector around sixty years ago 1 – 3 it has been employed in medical research and biology 4 , 5 , neutron dosimetry 6 – 8 , space physics 9 – 11 , nuclear physics 12 – 14 , laser-matter interactions and ion acceleration 15 – 25 , as well as in fusion experiments with deuterium–tritium 26 – 32 or proton-boron fuels 33 – 42 , to name a few. In the demonstration of fusion energy output exceeding the laser energy on target (scientific breakeven or Q > 1) in December 2022 43 , CR-39 was used–among other detectors–to measure the fusion neutron yield at the National Ignition Facility (NIF) 7 .…”

Target and PADC Track Detectors for Rare Isotope Studies

“…To improve the EURISOL detection capability, a complementary system is proposed, since a large set of experimental results have been obtained with passive polyallyldiglicolcarbonate, PADC for short, or (C 12 H 18 O 7 ) detectors in nuclear interaction studies by Barbui et al [5]. The technique demonstrated their importance in several fields, for example, in galactic cosmic ray (GCR) and studies on the ISS, Pálfalvi et al [6]. In the next sections, some technical details are given on a new target for the Eurisol facility that will be available in the near future.…”