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Abstract: After the security related occurrences in the past few years, there is an increasing need for airport security and border controls. In the combat against terror and smuggling, X-rays are used for the screening of persons and vehicles. The exposure of humans to ionising radiation raises the question of justification. To solve this question, reliable and traceable dose values are needed. A research project of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety was initiated. Its task is to measure the ambient dose equivalent, H*(10), and the personal dose equivalent, H p(10), for typical types of personnel and vehicle X-ray scanners, using the transmission and/or backscatter method. In the following, the measuring quantities which are to be used for these investigations will be discussed and the measuring instruments will be presented. Furthermore, the experimental set-up is described. For the personnel X-ray scanners investigated, the obtained dose values are in the range from 0.07 to 6μSv. These values will be compared to the dose values of the natural environmental radiation and some exposures in the field of medicine. [Copyright &y& Elsevier]

Purpose: The aim of this study was to investigate whether a chamber-type-specific radiation quality correction factor kQ can be determined in order to measure the reference air kerma rate of 60Co high-dose-rate (HDR) brachytherapy sources with acceptable uncertainty by means of a well-type ionization chamber calibrated for 192Ir HDR sources. Methods: The calibration coefficients of 35 well-type ionization chambers of two different chamber types for radiation fields of 60Co and 192Ir HDR brachytherapy sources were determined experimentally. A radiation quality correction factor kQ was determined as the ratio of the calibration coefficients for 60Co and 192Ir. The dependence on chamber-to-chamber variations, source-to-source variations, and source strength was investigated. Results: For the PTW Tx33004 (Nucletron source dosimetry system (SDS)) well-type chamber, the type-specific radiation quality correction factor kQ is 1.19. Note that this value is valid for chambers with the serial number, SN ≥ 315 (Nucletron SDS SN ≥ 548) onward only. For the Standard Imaging HDR 1000 Plus well-type chambers, the type-specific correction factor kQ is 1.05. Both kQ values are independent of the source strengths in the complete clinically relevant range. The relative expanded uncertainty (k = 2) of kQ is UkQ = 2.1% for both chamber types. Conclusions: The calibration coefficient of a well-type chamber for radiation fields of 60Co HDR brachytherapy sources can be calculated from a given calibration coefficient for 192 Ir radiation by using a chamber-type-specific radiation quality correction factor kQ. However, the uncertainty of a 60Co calibration coefficient calculated via kQ is at least twice as large as that for a direct calibration with a 60Co source. [ABSTRACT FROM AUTHOR]