Selfcalibrated alanine EPR dosimeters: A new generation of solid state EPRdosimeters

Alanine/EPR dosimeters are well established as secondary, reference dosimet ers for high-energy radiation. However, there are various sources of uncert ainty in the evaluation of absorbed dose. This arises primarily from the ne cessity to calibrate each EPR spectrometer and each batch of dosimeters bef ore their use. In order to overcome this disadvantage, a new generation ala nine/EPR dosimeter has been developed, and its possibilities as a radiation detector are reported. Principally, it is a mixture of alanine, some quant ity of EPR active substance, and a binding material. The EPR active substan ce, acting as an internal EPR standard, is chosen to have EPR parameters wh ich are independent of the irradiation dose. The simultaneous recording of the spectra of both the sample and the standard under the same experimental conditions and the estimation of the ratio I-alanine/I-Mn as a function of the absorbed dose strongly reduces the uncertainties. The response of thes e dosimeters for Co-60 gamma-radiation exhibits excellent linearity and rep roducibility in the range of absorbed dose, 10(2)-5.10(4) Gy.