Proton beam profile measurements and fluence rate monitoring of the associated proton experimental platform at CSNS

The China Spallation Neutron Source (CSNS) has built an Associated Proton Experimental Platform (APEP) at the end of its linear accelerator, playing an important role in space device radiation testing, detector calibration, material radiation research, and other applications. The proton beam profile and real-time fluence rate are crucial parameters for experiments conducted at APEP, making their measurement and monitoring essential. In this paper, we systematically measured and analyzed the beam spot profiles of multiple standard beam modes of the APEP, ranging from 10×10 mm 2 to 50×50 mm 2 , using an Al 2 O 3 (Cr) scintillating screen and a camera. The variation of beam profile uniformity with proton energy was also investigated. To meet the requirements of high-precision experiments such as single-event effects, a Secondary Electron Emission Monitor (SEEM) was developed for real-time monitoring of the proton beam fluence rate, covering the application range of 1.2×10 7 to 4.0×10 9 cm -2 ·s -1 . It was verified that the monitoring data exhibits a good linear relationship with the fluence rate at the same proton energy. These measurements serve as an important foundation for experiments on APEP, providing necessary key data for various experimental studies.