Intercomparison measurements with energy deposition spectrometer Liulin and TEPC Hawk at HIMAC, and related calculations with PHITS

Autor: Ploc, Ondrej, Uchihori, Yukio, Kitamura, Hisashi, Kodaira, Satoshi, Dachev, Tsvetan, Spurny, Frantisek, Iva, Jadrnickova, Mrazova, Zlata, et.al
Jazyk: angličtina
Rok vydání: 2010
Popis: Liulin type detectors are recently used in a wide range of cosmic radiation measurements, e.g. at alpine observatories, onboard aircrafts and spacecrafts. They provide energy deposition spectra up to 21 MeV, higher energy deposition events are stored in the last (overflow) channel. Their main advantages are portability (about the same size as a pack of cigarettes) and ability to record spectra as a function of time, so they can be used as personal dosimeters. Their well-known limitations are: (i) the fact that they are not tissue equivalent, (ii) they can be used as LET spectrometer only under specific conditions (broad parallel beam), and (iii) that the energy deposition event from particles of LET_H20>35 keV/m is stored in the overflow bin only so the spectral information is missing. Tissue equivalent proportional counter (TEPC) Hawk has no of these limitations but on the other hand, it cannot be used as personal dosimeter because of its big size (cylinder of 16 cm diameter and 34 cm long). An important fraction of dose equivalent onboard spacecrafts is caused by heavy ions. This contribution presents results from intercomparison measurements with Liulin and Hawk at Heavy Ion Medical Accelerator in Chiba (HIMAC) and cyclotron beams, and related calculations with PHITS (Particle and Heavy-ion Transport code System). Following particles/ions and energies were used: protons 70 MeV, He 150 MeV, Ne 400 MeV, C 135 MeV, C 290 MeV, and Fe 500 MeV. Calculations of LET spectra by PHITS were performed for both, Liulin and Hawk. In case of Liulin, the dose equivalent was calculated using simulations in which several tissue equivalent materials were used as active volume instead of the silicon diode. Dose equivalents calculated in such way was compared with that measured with Hawk. LET spectra measured with Liulin and Hawk were compared for each ion at several points behind binary filters along the Brag curve. Good agreement was observed for some configurations; for the other configurations, the difference was reasonably described (e.g. thickness of stainless steel of TEPC wall and size of Hawk's active volume).
38th COSPAR Scientific Assembly
Databáze: OpenAIRE