Setting the Triggering Thresholds on Swift

Journal Article · Tue Sep 28 04:00:00 EDT 2004 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1810931· OSTI ID:20630208

McLean, Kassandra M ^[1]; Fenimore, E E; Palmer, David ^[1]; Barthelmy, S; Gehrels, N; Krimm, H; Markwardt, C; Parsons, A ^[2]

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1. Los Alamos National Laboratory (United States)
2. Goddard Space Flight Center (United States)

The Burst Alert Telescope (BAT) on Swift has two main types of 'rate' triggers: short and long. Short trigger time scales range from 4ms to 64ms, while long triggers are 64ms to {approx_equal} 16 seconds. While both short and long trigger have criteria with one background sample (traditional 'one-sided' triggers), the long triggers can also have criteria with two background samples ('bracketed' triggers) which remove trends in the background. Both long and short triggers can select energy ranges of 15-25, 15-50, 25-100 and 50-350 KeV. There are more than 180 short triggering criteria and approximately 500 long triggering criteria used to detect gamma ray bursts. To fully utilize these criteria, the thresholds must be set correctly. The optimum thresholds are determined by a tradeoff between avoiding false triggers and capturing as many bursts as possible. We use realistic simulated orbital variations, which are the prime cause of false triggers.

• OSTI ID: 20630208
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 727; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COSMIC GAMMA BURSTS
COSMIC GAMMA SOURCES
COSMIC PHOTONS
COSMIC RAY DETECTION
GAMMA DETECTION
KEV RANGE
SATELLITES
TELESCOPE COUNTERS
VARIATIONS