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Alanine Electron Paramagnetic Resonance (EPR) dosimetry

The EPR dosimetry provides information about the absorbed dose to a medium through measuring the concentration of the free radicals produced by ionizing radiation. From the early sixties the development of alanine/EPR dosimetry has reached a level that makes it competitive with classical methods of dosimetry such as thermoluminescence, chemical and ionization methods, at least at the higher dose range (above 5 Gy). The alanine detectors in form of pellets are provided by the National Physical Laboratory (NPL). The detectors have a nominal diameter of 5.0 mm and a thickness of about 2.3 mm. The pellets consist of 90.9% by weight L-α-alanine and 9.1% high melting point paraffin wax. The average density is around 1.22 g cm3 actually close to PMMA (density 1.19 g cm3), but varies slightly from batch to batch.