Speaker
Description
Focusing on the high precision dose distribution monitoring in the spot scan beam delivery system of proton therapy, we design and fabricate a high-precision ionization chamber with multiple strip electrodes, ensuring a stable gain from the ionized pair. Based on advanced laser etching technology, using aluminum-plated polyimide film as the electrode material, we investigated multiple fabrication parameters to produce high-precision, flexible strip PCBs. Using these flexible PCBs as central detection parts, we designed a large-area parallel plate ionization chamber with integrated dose and position monitoring. The reported ionization chamber has a sensitive area of 250 mm by 250 mm, comprising 256 channels in the X-direction and 256 channels in the Y-direction, along with two mutually verifiable integral plane electrodes. The ultra-thin film electrodes and window materials allow for virtually non-invasive ion beam measurements with a water-equivalent thickness of less than 0.3 mm. This ionizing chamber can be integrated into the nozzle of a proton therapy system to measure beam spot position in real-time. It also provides precise dose distribution information and can be integrated into quality assurance systems to make diagnostics at the iso-center. The design, fabrication results, and calibration of the large-area domestic ionization chamber will be reported in this paper.
Footnotes
*: Corresponding Author, Dr. Zhiguo Yin, Email: yinzhiguo@cnncmail.cn
