Backscattering factor for some personal dosimeters and impact on Hp(10)

¹ Department of Physics, Karnatak University, Dharwad, 580003, India.
² Radiological Physics & Advisory Division, BARC, Mumbai, 400094, India.

^* Permanent address: Health Physics Section, Kaiga Atomic Power Station-3&4, NPCIL, Karwar, 581400, Karnatak, India, e-mail: kudphyvps@rediffmail.com

Received: 29 May 2012
Accepted: 19 November 2012

Abstract

In the present paper, we estimated backscattering factors for the TLD and active personal dosimeters using 662 keV gamma-ray photons on a PMMA surface, which are, for the TLD, 1.12; Dosicard, 1.116; DRD, 0.99; and Saphydose, 1.073, and on a water slab phantom surface; for the TLD, 1.115; Dosicard, 1.112; DRD, 1; and Saphydose, 1.059. The backscattering factor contribution for the Saphydose is nearly half that of the TLD and Dosicard, whereas it is zero for the DRD. The DRD underestimates Hp(10) by 10.3–11.6%, whereas for the Saphydose it is 3.4–5% compared with the TLD or Dosicard. The response of the DRD to Hp(10) is nearly independent of the phantom, whereas the TLD, Dosicard and Saphydose require phantoms for calibration for personal monitoring. It is observed that the PMMA phantom contributes slightly higher backscattering compared with the water slab phantom. The backscattering factor of the selected dosimeters is comparable with ICRU tissue already reported.