Abstract
Quality of low and medium energy X-ray beam at the National Institute for Standards (NIS) of Egypt is studied in details in accordance with the recommendations of the Bureau International des Poids et Measures (BIPM) consultative committee for ionizing radiation (CCRI). The Half Value Layer (HVL) at each applied voltage is precisely determined. The setting up for the X-ray tube according to the TRS No. 469 of IAEA is performed. The effective energy of X-ray is determined using Hyper Pure Germanium Detector (HPGD) connected to photon energy spectrometer. The X-ray air Kerma is measured using NIS secondary standard dosimetry system, which is traceable to the SI units through BIPM. A proposed method for non-invasive tube voltage determination by HPGD is performed. Consequently, all X-ray beam quality parameters are extracted and found to be complying with CCRI recommended values for NIS X-ray tube.
This work comprised study on the characterization of NIS low and medium energy X-ray as well as the development of the X-ray laboratory to perform its role in calibrations and to supply customers with traceability to SI units. It gave NIS the ability to participate in international measurement comparisons. A PTW quality assurance set for X-ray is calibrated against the studied X-ray beam qualities to fulfill the requirements of customers needs. The absolute air Kerma for medium energy X-ray is determined using a primary standard free air chamber. Two ionization chambers are calibrated and the calibration factors are compared with values obtained at the BIPM. (C) 2012 Elsevier Ltd. All rights reserved.