Invited Lecture 1.1
Title : Modified Electron Beam Calibration: The Concept and Implementation
Date: 11th October 2024
Time: 02:30pm – 02:45pm
Venue : Ballroom 1 (Level 10)
Chairs:
- Hafiz Zin
Speaker: Dr. Supriyanto Ardjo Pawiro (Indonesia)
Abstract
Several international dosimetry protocols recommend using parallel-plate chambers for electron beam measurements, especially for low-energy electrons. Electron beam measurement using a parallel-plate chamber can effectively minimize fluence perturbation as the front windows of a parallel-plate chamber are thin and composed of materials with similar properties to water; therefore, the effect of the wall can be neglected. Some protocols do not recommend using a cylindrical chamber for electron beam dosimetry at low energies. This is because a cylindrical chamber can have a large fluence correction factor, which could be a source of high uncertainty. A more recent publication states that the variability in perturbation corrections for cylindrical chambers is 0.4%, and the results are not significantly different from those for parallel-plate chambers with the same specifications. They proposed a cylindrical chamber for reference dosimetry of all electron beams. Additionally, literature has shown superior long-term stability of a cylindrical chamber in an electron beam than parallel-plate chambers. The implementation of modified electron beam procedure which is tested in several institutions in both standard and high dose rate electron beams will be presented. The comparison of output measurement using the modified electron beam calibration to standard calibration methods present the discrepancy less than 2% for multicentre study and cross calibration procedures.