Design Of An EPICS Based Beam Loss Detection For HUST-PTF

Among the many cancer treatment methods,proton radiotherapy is considered to be the most accurate non-invasive treatment.Huazhong University of Science and Technology and China Academy of Atomic Energy hosted the National 13 th Five-Year Key R&D Program "Development of Proton Radiotherapy Equipment Based on Superconducting Cyclotron",which aims to develop a set of proton radiotherapy equipment.The 250 Me V superconducting cyclotron,beam transport line,treatment room and corresponding diagnostic control system are composed.What this paper studies is the detection of beam loss in diagnostic systems.Beam loss detection is an important part of the beam diagnosis system of the whole device.For the 250 Me V proton accelerator,beam loss may occur due to various factors such as orbital distortion,magnet failure,and excessive beam envelope during machine operation.After the proton beam hits the wall of the vacuum chamber,it will generate radioactive particles such as X-rays,Gamma rays,and neutrons,which may cause major safety hazards to the surrounding environment and equipment.Therefore,a beam loss monitoring system must be designed to provide a guarantee for the safe operation of the machine.On the other hand,beam loss detection also provides auxiliary information for machine commissioning.The data obtained by beam loss detection is an important basis for the setting and correction of machine operating parameters,and is of great significance for ensuring the normal and stable operation of the machine.This paper systematically studies the beam loss detection of the accelerator system:(1)Analyze and calculate the loss rate of the dipole or quadrupole through the transmission line,which is the installation of the beam loss detector on the beam transmission line The location provides a preliminary basis;(2)The Monte Carlo simulation software GEANT4 and FLUKA were used to simulate the distribution of secondary particles on the wall of the stainless steel vacuum tube and the beam loss detected by the scintillator detector.Simulation calculation,analysis of the dose distribution on the scintillator and the feasibility of beam loss detection using a detector measuring gamma photons under different environmental conditions and angles;(3)According to the calculation and simulation results,the beam transmission line is given Reference deployment plan for the upper beam loss probe.In this paper,through the study of EPICS software tools,a typical distributed control system is established,and the establishment of the beam loss system and the device control based on the serial port protocol are realized.Based on the EPICS architecture,each functional module is built based on the system requirements.Among them,for serial devices,analysis and design are mainly from two aspects of hardware and software.Through Asyn and Stream Device two software packages,serial software support modules and application programs are built to achieve serial data reading,writing,Display and monitoring,etc.For the beam loss monitoring equipment,based on the analysis of its existing database files,combined with actual needs,by connecting the equipment to the EPICS control system,extracting useful data into the database,the beam control is realized on the operator control interface For the control of loss monitoring equipment,the main functions include channel selection,sampling signal control,alarm and switching of beam loss detection type.