Singh Sunil K, Kulkarni M S
Radiation Safety Systems Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India.
Homi Bhabha National Institute, Anushaktinagar, Mumbai 94, India.
Radiat Prot Dosimetry. 2018 Dec 1;182(2):215-220. doi: 10.1093/rpd/ncy051.
Measurement of dose due to low and medium energy X-ray using an ionization chamber needs special considerations as the wall thickness of the detector plays an important role in signal generation. A thin and plane wall ionization chamber having 900 cc volume was developed to study its calibration coefficient with air kerma (Kair) rate and ambient dose equivalent (H*(10)) rate at various X-ray beam qualities generated from a dosimetry grade X-ray machine. Optimized ionization chamber wall thickness was determined through measurements where a flat energy response of the ionization chamber could be established. The measurement shows that the air kerma rate based calibration coefficient for ionization chamber varies up to 45% and ambient dose equivalent rate based calibration coefficient varies up to 20% for wall thickness 1.2-1200 mg/cm2 in the energy range 17.6-213 keV.
使用电离室测量低能和中能X射线的剂量需要特殊考虑，因为探测器的壁厚度在信号产生中起着重要作用。为了研究其在剂量学级X射线机产生的各种X射线束质下与空气比释动能率（Kair）和周围剂量当量率（H*(10)）的校准系数，研制了一种体积为900 cc的薄壁平面电离室。通过测量确定了优化的电离室壁厚度，在该厚度下可以建立电离室的平坦能量响应。测量结果表明，在17.6 - 213 keV能量范围内，对于1.2 - 1200 mg/cm2的壁厚度，基于空气比释动能率的电离室校准系数变化高达45%，基于周围剂量当量率的校准系数变化高达20%。
