The Alanine Radiation Detector for High and Low-LET Dosimetry

Abstract

The amino acid L-a-alanine has been investigated for use as a radiation detector in low and high LET radiation fields. Data concerning detector sample preparation, dose-response relationships, fading of radiation induced response, and measured and calculated radiation sensitivity to heavy charged particles are presented. A new binding material, polyvidone, has been tested and compared with cellulose and paraffin. It combines the good mechanical properties of cellulose pellets with the absence of zero dose signal in paraffin pellets. Heating to 423 K for 30 min does not change the mechanical properties or radiation sensitivity. Dosemeters were prepared by pressing microcrystalline alanine powder with 5% polyvidone binder into small pellets, which after exposure to ionising radiation were measured by means of electron spin resonance (ESR) spectroscopy. The radiation detector is cheap and easy to handle. The low LET radiation induced free radicals are stable at normal laboratory conditions for doses below 104 Gy over a long period of time, which makes the detector useful for intercomparison and documentation purposes. Fading of radiation induced response has been observed in alanine detectors exposed to high LET radiations and to high doses of low LET radiation.