Bilateral comparison of an alanine/ESR dosimetry system at radiotherapy dose levels

Abstract

To improve the signal to noise ratio and to reduce the uncertainty for Electron Spin Resonance (ESR) readout of alanine dosimeters irradiated in the dose range of 2–10 Gy, new spectrometer settings have been proposed for microwave power, modulation amplitude, conversion time, sweeps of the spectrum and orientations of the alanine pellets ( Garcia et al., 2009 ). To check the reliability of the new spectrometer settings at radiotherapy dose levels, a bilateral dose comparison in terms of absorbed dose to water was performed between the CEA LIST Laboratoire National Henri Becquerel (LNHB) and the Radiometrology Center of the China Institute of Atomic Energy (RC-CIAE). Eighteen alanine dosimeters were irradiated with 2, 5 and 10 Gy. Each dosimeter was readout with the new spectrometer settings developed within the framework of the collaboration. The results of D meas / D nom at both laboratories in the dose range of 2–10 Gy are within the tolerance limits. The maximum deviations observed are within the extended uncertainties ( k = 2).