Detection of high energy neutrons, protons and He particles by solid state nuclear track detectors

Abstract

Abstract The career of astronauts is dependent mostly on the lifetime dose received from primary cosmic rays and secondary particles generated within the structuring materials of a space craft. Since the high energy protons and He particles have the highest abundance and the secondary neutrons significantly contribute to the dose, the study of the response of solid state nuclear track detectors (SSNTD) to these particles has a great importance. SSNTDs, having been used for dosimetry on the International Space Station (ISS), were exposed to protons at several accelerators (Loma-Linda, BNL, TSL), to He (HIMAC) and to neutrons (iThemba, TSL). The incident particles cause fragmentation of the constituent elements of the SSNTD composed of C 12 H 18 O 7 . The fragments induce latent tracks inside the detector which can be visualized by chemical processes and investigated by optical microscope. The measurable track parameters and appropriate calibration allow to determine the linear energy transfer (LET) spectrum of the fragments and also the absorbed dose in the nearly tissue equivalent detector material. The LET spectra of different exposures are presented and compared. Additionally, a LET spectrum determined from the MATROSHKA space walk simulation outside the International Space Station (ISS) will be compared to some of those obtained from accelerator experiments.