Improvement of the LET sensitivity in ESR dosimetry for gamma photons and thermal neutrons through gadolinium addition

We investigated the ESR response of new materials, alanine and ammonium tartrate to which gadolinium was added. The addition of gadolinium enhances sensitivity for 60Coγ -photons because of its high atomic number (Z = 64) and an enhancement of sensitivity for thermal neutrons because of its high thermal neutron cross section and high linear energy transfer (LET) secondary particles produced after the reaction with neutrons. In particular, in this paper we analyzed the microwave power saturation properties of dosimeters of alanine and ammonium tartrate with or without gadolinium exposed to different LET beams. The power saturation trends of dosimeters exposed to photons and to thermal neutrons are different. For ammonium tartrate dosimeters the gadolinium addition intensifies significantly these differences and therefore, it improves the ammonium tartrate's ability to discriminate the radiation LET .