Lens dosimetry study in Sr+Y beta field; Full-face mask respirator shielding and dosemeter positioning

Tsujimura, Norio   ; Hoshi, Katsuya ; Yamazaki, Takumi ; Momose, Takumaro  ; Aoki, Katsunori ; Yoshitomi, Hiroshi   ; Tanimura, Yoshihiko   ; Yokoyama, Sumi*

To investigate the shielding effects of full-face respirator masks and the suitable positioning of lens dosemeters, irradiation experiments of Sr+Y beta particles were performed using an anthropomorphic head phantom into the eyes of which small thermoluminescence dosemeters (TLDs) were loaded, and the lens doses measured by these TLDs were compared with the doses measured by commercially available personal dosemeters attached around the eyes of the phantom. The three tested masks reduced the beta lens dose to 9-14% as compared to the lens doses in the absence of a mask. As for the suitable positioning of lens dosemeters, the (0.07) evaluated by the (0.07) dosemeter attached at the center of the forehead gave an over-response to the lens dose by a factor of 2.5-8.4 regardless of the presence of masks. The (3) evaluated by the (3) dosemeters, even though placed at extreme positions near the outside corners of the eyes, provided better lens dose estimates with a response of 0.38-1.7.