Beam-line Diagnostics at the Front End Test Stand (FETS), Rutherford Appleton Laboratory, Oxfordshire, UK

Gary Boorman, Stephen Gibson, R. D'Arcy, Simon Jolly, Christoph Gabor, Scott Lawrie, Alan Letchford

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The H− ion source and beam-line at FETS will require the beam current and beam position to be continually monitored. Current transformer toroids will measure the beam current and beam position monitors (BPM) will determine the beam position. The ion source delivers pulses at a rate of 50Hz with a current up to 60mA, each pulse is 2ms long, and a 324MHz micro-bunch structure imposed by the radio frequency quadrapole (RFQ) accelerating structure. The toroid outputs will be acquired on a fast oscilloscope. The BPM design is still under consideration (shorted strip-line or button type) but the processing for both types is similar and has been designed, with simulated measurements made. Each BPM uses four pickups, at a frequency of 324MHz, which are mixed using RF electronics to an intermediate frequency of 10.125MHz. The resulting signals are then digitized at 40.500MHz and processed in an FPGA to produce the position and phase of the beam at each BPM location, with a precision of better than 100μm and 0.05rad. The measurements from the toroids and BPMs will be via EPICS servers at every pulse.
Original languageEnglish
Title of host publication2nd International Beam Instrumentation Conference
Subtitle of host publication16-19 September 2013, Oxford, UK.
ChapterBPMs and Beam Stability
Number of pages4
ISBN (Electronic)978-3-95450-127-4
Publication statusPublished - 19 Sept 2013

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