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Dawson, C.

Publications and source records attributed to Dawson, C..

6 records
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DOE OSTI2018

Error-Correcting Codes for Code-Division Multiplexed TES Detectors

Transition edge sensors (TESs) have proven to be highly sensitive and versatile X-ray spectrometers. Upcoming missions, including Athena X-IFU, will rely on highly multiplexed focal planes where more than 32 TES pixels are read out using a single SQUID amplifier channel. We have implemented an error correction algorithm for code-division multiplexed TES signals that can compensate for potential failures of individual SQUID readout channels and that is both scalable and easily implemented in hardware. We present this algorithm for error correction and show results of laboratory tests to assess algorithm performance at recovering TES channels after a SQUID failure.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

A Spread-Spectrum SQUID Multiplexer

The transition-edge sensor (TES) is a mature, high-resolution x-ray spectrometer technology that provides a much higher efficiency than dispersive spectrometers such as gratings and crystal spectrometers. As larger arrays are developed, time-division multiplexing schemes operating at MHz frequencies are being replaced by microwave SQUID multiplexers using frequency-division multiplexing at GHz frequencies. However, the multiplexing factor achievable with microwave SQUIDs is limited by the high slew rate on the leading edge of x-ray pulses. In this paper, we propose a new multiplexing scheme for high-slew-rate TES x-ray calorimeters: the spread-spectrum SQUID multiplexer, which has the potential to enable higher multiplexing factors, especially in applications with lower photon-arrival rates.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Run 16, eIPM Summary

Three problems with the eIPMs were corrected during the 2015 summer shutdown. These involved ac coupling and 'negative profiles', detector 'dead zone' created by biasing, and gain control on ramp. With respect to Run 16, problems dealt with included gain depletion on horizontal MCP and rf pickup on profile signals; it was found that the MCP was severely damaged over part of the aperture. Various corrective measures were applied. Some results of these measured obtained during Run 16 are shown. At the end of Run 16 there was a three-­day beam run to study polarized proton beams in the AGS. Attempts to minimize beam injection errors which increase emittance by using the eIPMs to measure the contribution of injection mismatch to the AGS output beam emittance are recounted. .

43 PARTICLE ACCELERATORS↗