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Persistent URL http://purl.org/net/epubs/work/32027597
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Record Id 32027597
Title Computing Bunch Charge, Position, and BPM Resolution in Turn-by-Turn EMMA BPMs
Abstract The NS-FFAG electron model ‘EMMA’ and its Injection and Extraction Lines are equipped with a total of 53 EPICS VME BPMs*. In the BPMs, each opposite button signal pair is time-domain-multiplexed into one channel as a pulse doublet. The recording of turn-by-turn data into the BPM memory is triggered by the bunch itself on each of its passages. For each accelerating cycle, the BPMs deliver a snapshot of a turn-by-turn trajectory measured in each of 42 cells. Additional BPMs (two pairs) are used to obtain a Poincare map. We describe the EPICS architecture, and a set of Python data processing algorithms that are used to automatically set a BPM intensity range, to eliminate an error due to tails of the doublet pulses, to calculate the bunch charge and position, and, for a set of injections, to find the BPM resolution. We use three types of button pickup mappings** that allow: to eliminate bunch charge signal dependence on offset, to get a linear offset response, and to eliminate ‘quadrupole’ signal dependence on offset as well (which is used in resolution calculation). We present beam measurement results collected in 2011 runs.
Organisation ASTeC , ASTeC-AP , CI , STFC
Keywords ASTeC 2012-2013 , Physics
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Language English (EN)
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Paper In Conference Proceedings In 3rd International Particle Accelerator Conference (IPAC'12), New Orleans, Louisiana, USA, 20-25 May 2012, (2012): 924. http://accelconf.…/papers/moppr061.pdf 2012