Technique for increasing reproducibility in EPR dosimetry of tooth enamel

Variations in several electron paramagnetic resonance (EPR) spectral parame ters of importance in retrospective dosimetry of tooth enamel were measured using instrumentation and methodologies designed to maximize measurement r eproducibility. Measurements were made using accessory EPR equipment that c an be readily constructed with little more than a variable power supply, a geared down motor and some high-purity CaO. Spectroscopic precision is cons iderably enhanced due to elimination of sample anisotropies by scanning sam ples throughout their angular range. Frequency drifting incurred by sample reorientation and instrument/sample warm-up is effectively eliminated using an in-cavity Mn++:CaO standard. This work shows that for highly anisotropi c samples, spectral characteristic parameters (peak-to-peak amplitudes, sig nal component widths and positions) are reproduced with equal or comparable precision to the case where standard EPR configurations are used while mea suring approximately isotropic samples.