The Energy Spread Measurement Of Beam Based On The Scattering Model Detector

Developed by the Institute of Modern Physics, CAS, the Heavy Ion MedicalMachine(HIMM) injector is a compact cyclotron, whose intensity, energy spread,emittance of the extraction beam are of higher quality. In order to accurately measurethe energy spread, the detection system is expected to have high detection efficiencyand energy resolution.Based on the Rutherford scattering principle, this paper studiesthe detection system which can monitor the extraction beam energy spread and isconstructed by a silicon detector and a MCP TOF detector in different directions.Silicon detectors for nuclear radiation detection have high energy resolution,rapid rise time and so on; and micro-channel plates have good time resolution.Therefore, detectors based on MCP have been greatly applied in the beammeasurement. This paper describes the performance of silicon detectors and discussesthe effect of position and angle of silicon detectors. And the energy resolution anderror analysis are also involved. Besides, this paper highlights the structural design ofMCP TOF detectors, focusing on the performance of the anode shapes and thebandwidth of the signal transmission lines. Furthermore, offline test TOF detectorerror: ? particles, electrons flying error and timing accuracy are analyzed andcalculated. The test shows that the rise time is 260 ps and the system time resolution is90 ps.Early 2015, the online test for HIMM compact cyclotron was carried out. As thetest result shows, the measured energy spread of the detector is less than 1%, whichcould meet the design requirement. Moreover, considering it brings in 1 ‰ or lessenergy broadening error when the particles pass through the gold target, to somedegree, the beam energy spread and the energy spread of extraction beam are regardedequal. Considering the intrinsic detector resolution, the extraction beam of theaccelerator can achieve the desired better than 1% energy spread. Meanwhile, thefeasibility and superiority of the scattering beam detector have also been confirmed.