Beam Chopping Control using Digital Pulse Generators

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In experimental measurements of statistical nature, signal must be extracted from background noise. This applies to the previous absolute cross section measurements of charge transfer [1] with the merged beams technique at the Oak Ridge National Laboratory Multicharged Ion Research Facility. Improvements to the chopping scheme is required to prepare for new high-resolution X-ray measurements from charge transfer between H and highly charged ions using merged beams. This is accomplished by chopping the two beams with pulses from a pair of digital pulse generators. Signal is measured with beam pulses in phase and merged while the background is measured with beam pulses out of phase and de-merged. Once the pulse generators are programmed, electronic counters are used to ensure there are an equal amount of merged and de-merged pulses.

Research is supported by NASA Astrophysics Research and Analysis Grant No. NNH18ZDA001N.