We report the design and test results of a beam monitor developed for online monitoring in hadron therapy. The beam monitor uses eight silicon pixel sensors, \textit{Topmetal-II−}, as the anode array. \textit{Topmetal-II−} is a charge sensor designed in a CMOS 0.35 μm technology. Each \textit{Topmetal-II−} sensor has 72×72 pixels and the pixel size is 83×83μm2. In our design, the beam passes through the beam monitor without hitting the electrodes, making the beam monitor especially suitable for monitoring heavy ion beams. This design also reduces radiation damage to the beam monitor itself. The beam monitor is tested with a carbon ion beam at the Heavy Ion Research Facility in Lanzhou (HIRFL). Results indicate that the beam monitor can measure position, incidence angle and intensity of the beam with a position resolution better than 20 μm, angular resolution about 0.5∘ and intensity statistical accuracy better than 2%.
@article{arxiv.1611.07147,
title = {A beam monitor using silicon pixel sensors for hadron therapy},
author = {Zhen Wang and Shuguang Zou and Yan Fan and Jun Liu and Xiangming Sun and Dong Wang and Huili Kang and Daming Sun and Ping Yang and Hua Pei and Guangming Huang and Nu Xu and Chaosong Gao and Le Xiao},
journal= {arXiv preprint arXiv:1611.07147},
year = {2017}
}