Electron paramagnetic resonance radiation dosimetry: possible inorganic alternatives to the EPR/alanine dosimeter

Abstract

The intensity of the EPR spectrum of γ-irradiated L-α-alanine has been accepted by the International Atomic Energy Agency as a secondary standard for high-dose (10–100 000 Gy) dosimetry. The alanine dosimeter is not without its disadvantages, however, and in this article alternative EPR dosimeters are explored. These include SO^–₃ in irradiated K₂CH₂(SO₃)₂ and CO^–₂ in irradiated sodium formate (NaHCO₂), both of which have some advantages over CH₃CHCO^–₂ in L-α-alanine. Using as a readout parameter the peak-to-peak excursion of the strongest line, these systems have a four-fold sensitivity advantage over alanine. The radicals SO^–₃ and CO^–₂ are, moreover, found in a wide variety of matrices, and it may be possible find one in which they are even stronger.

The need to discover a dosimeter material sensitive enough to function in the ‘clinical’ dose range (below 10 Gy) is emphasized.