Eye lens dosimetry for workers at Fukushima Daiichi Nuclear Power Plant—1: Laboratory study on the dosemeter position and the shielding effect of full face mask respirators

We conducted an eye lens dosimetry study on workers, engaged in recovery and decommissioning operations at Fukushima Daiichi Nuclear Power Station. To investigate the optimal positioning of eye lens dosemeters and the shielding effect of full face mask respirators, photon irradiation experiments to various eye lens dosemeters attached to a head phantom were performed at the secondary photon calibration fields of the Japan Atomic Energy Agency. As a result, no marked difference was observed in readings of the dosemeters attached to the different positions on the head phantom. Moreover, two types of full face mask respirators provided an insignificant shielding effect from photons of 83–662 keV. Comparative measurements between AP and ROT geometries suggested that head-mounted dosemeters would generally produce a small angular variation in readings specifically in multidirectional fields as compared to the torso-mounted dosemeters.