Development Of Beam Position Measure System For Compacting THz-FEL Source Linear Accelerator

Development of the beam position measurement system on THz-FEL linac was proposed in this paper. This THz-FEL linac work on2856MHz micro-pulse frequency and the macro-pulse width is6μs. In order to measure the beam position, a stripline beam position monitor (BPM) was designed. To process the sensing signal of BPM, a commercial BPM electronics Libera Brilliance Single Pass was adopted. For the carrier frequency of the BPM electrode signal is2856MHz and however the operating frequency of the Libera Brilliance Single Pass is500MHz, a front-end electronics between the electrode and processor was designed. The main function of the front-end electronics was convert the2856MHz BPM electrode signals to500MHz to suit the processor working frequency. We also build a set calibration platform to test and verify the BPM system offline.Firstly, the design of BPM front-end electronics is introduced. This electronics module includes LO signal source, RF amplifier module and mixing module. LO signal source module is used to produce a2356MHz signal, and this signal is also used to be mixed and BPM electrode signal, RF amplifier module is used to enlage strip electrode signal to meet mixer, and mixing module is used to mix stripline electrode signal to500MHz. Secondly, this paper mainly described the design of stripline BPM, and processing it. Then building a platform for offline calibrating the stripline BPM. Finally, off-line calibration datas are analyzed. Test results show that, the performance of the hardware are satisfied for the beam position measurement demand of the compacting THz-FEL source linear accelerator.We used front-end electronics and Libera Brilliance Single Pass to test system Hardware integration, and designed measurement software about it.