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Modernization of the measuring facility for calibrations of radioactive sources and secondary brachytherapy standards


The newly developed measuring facility is used to automatically calibrate HDR brachytherapy sources and well‑type ionization chambers. The hardware was adapted to the department's existing hardware components and assembled in a modular fashion. This modular design ensures the exchangeability and compatibility of the individual components between the measuring facilities operated within the department. The software was developed in the Lazarus environment using the department's programming library.

Figure 1 shows the set‑up for the calibration of a well‑type ionization chamber, which includes the so‑called afterloading device that can be used to vary the position of the source.

By automating the measurement procedure, the duration of a complete calibration can be reduced from approximately three weeks to just one week.

Two different sources and four ionization chambers were used to validate the measuring facility and its new software. The calibration factors were determined using both the current and the new measuring facility. The deviations found here were not significant. They remained in the range of less than 0.2 %.

Fig. 1: Set-up for the calibration of a well-type ionization chamber


Opens local program for sending emailF. Grote, Department 6.3, Working Group 6.34