The impact of irradiation temperature estimations on the accuracy of dosimetry

Quality-control dosimetry is important to the routine operation of a radiation processing facility. For many applications this dosimetry must be traceable to a national primary standard. After irradiation at an industrial facility, National Institute of Standards and Technology (NIST)-supplied transfer dosimeters are certified by measurement and dose interpolation from the NIST calibration curve. However, prior to computing the absorbed dose the dosimeter response must be adjusted for the temperature difference between irradiation temperature for the alanine system calibration and the irradiation temperature for the industrial process. For most industrial applications, the temperature is not controlled and varies during the irradiation process. The alanine dosimeter response has a dependence on irradiation temperature, which is compensated for by applying a correction factor to the dosimeter response to compute the absorbed dose. Moreover, there is no consensus protocol to estimate the irradiation temperature and apply this correction. This work approximates industrial temperature profiles using a 60Co source with a temperature-controlled irradiation chamber, and then compares the relative effectiveness of commonly used industrial methods to correct for irradiation temperature influence on the alanine dosimeter response.