Design of the front-end electronics for parallel plate ion chamber

Background A set of nozzle systems for proton therapy is now being developed at China Institute of Atomic Energy. To realize the measurement of beam dose, a set of charge measurement electronics is designed, which is used to measure the output charge signal of the ionization chamber integration plane. Also, the charge measurement device can be used to measure the position information of ion chamber strips just by changing certain parameters. Methods The device realizes the integration and amplification of charge by IVC102, a precise low-noise integrator, and the DSP controls the ADC to collect and process the data. Modbus communication protocol is used to realize communication with the host computer which makes it possible to read data and set the parameter. Results A fixed charge generator is designed to generate 20 pC to 2 nC charge, which is used to test the measuring accuracy of electronics. The results have shown that the accuracy is within 0.62% in the above charge range. Conclusion After experimental tests, the front-end electronics meet the design goal and play a certain pre-test and verification role in the dose and beam position monitoring in the proton therapy system.