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Title: The APEX trigger processor

Journal Article · · Bulletin of the American Physical Society
OSTI ID:386990
 [1]
  1. Argonne National Laboratory, IL (United States)

Positron identification in APEX is accomplished via the detection of the characteristic back-to-back 511 keV gamma rays emitted when the positrons annihilate in the APEX silicon array. The photons are detected in NaI arrays that surround the silicon arrays. To trigger APEX we designed and constructed the APEX Trigger Processor (ATP). The ATP provides a hardware trigger based on the consistency of the NaI hit pattern with a set of pre-loaded patterns. The pattern look-up and trigger production occur within 80 ns (the ATLAS beam pulse period). The spurious trigger rate is dominated by room background events which generate true back-to-back hit patterns. These false triggers are easily rejected in hardware and software. The basic design and performance of he ATP, with and without beam, will be discussed.

OSTI ID:
386990
Report Number(s):
CONF-931044-; ISSN 0003-0503; TRN: 96:026928
Journal Information:
Bulletin of the American Physical Society, Vol. 38, Issue 9; Conference: Fall meeting of the Division of Nuclear Physics of the American Physical Society, Pacific Grove, CA (United States), 20-23 Oct 1993; Other Information: PBD: Oct 1993
Country of Publication:
United States
Language:
English

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