The 12 NaI
detectors are 1.27 cm thick by 12.7 cm diameter, directly coupled to a
12.7 cm diameter photomultiplier tube (PMT).
They provide spectral coverage from about 8 keV
to 1 MeV.
NaI is an ideal scintillation material for this energy range
combining low cost, high efficiency, and adequate spectral resolution.
The thickness of the detectors is optimum for the
energy range where bursts typically emit the most energy and
provides approximately a cosine angular response, which is important
for determining locations using relative rates, similar to
BATSE.
Lower energy coverage relative to BATSE
is obtained by using a 0.25 mm beryllium window to the
detectors. The detectors are arranged in 4 banks of 3 detectors
so that the larger
number of detectors, each viewing a smaller field-of-view, will
reduce systematic errors for burst locations and allow an improved
triggering algorithm.
NaI Detector on test bench in lab at NSSTC June 2005.
Closeup of NaI detector.
Gluing thermostat on Engineering Quality Model at Max Planck Institute April 2005.
NaI and BGO Detectors in thermal vacuum chamber at Max Planck.
Flight Module Detectors at Max Planck Institute:
Gluing heater on Flight Module at Max Planck Institute April 2005.
Assembly of NaI detector April 2005.
