The SWIFT BAT Software Guide Version 6.3 30 ... - HEASARC - Nasa

A.6. MAPS 75
A.6.2 Detector Quality Map
A detector quality map file (code “dqcb”) is a ground-derived product. The primary extension
contains a quality map indicating which detectors should be used for science analysis and which
should not (0=use; 1=discard). This file is typically the output of the bathotpix task, which
combines the detector enable/disable map (see “Enable/Disable Map” above) and counts map
which has been screened for noisy detectors.
Layout. Detector quality file
Extension Description
Primary 286×173 Map; Detector quality map (0=good; 1=bad)
BADPIX List of bad pixels
Layout. List of bad pixels. EXTNAME = ‘BADPIX’
Name Format [Units](Range) Comment
TIME 1D [s] Start time of hot pixel counts map
EXPOSURE 1D [s] Exposure of hot pixel counts map
DET ID 1J (0:32767) Detector identification number
DETX 1I [pixel](0:285) BAT X detector pixel number
DETY 1I [pixel](0:172) BAT Y detector pixel number
QUALITY 1I Detector quality flag
COUNTS 1J [count] Number of counts in flagged detector
The QUALITY flag can take the following values.
QUALITY Meaning
0 Good
1 disabled detector
2 cold or undersensitive detector
3 hot or noisy detector
A.6.3 Gain / Offset Map
Gain/offset maps (code “gocb”) are produced by the BAT on-board automatic calibration system,
and provide the linear transformation from pulse height to keV. This map is used with other
calibration files to produced calibrated energy values for event and survey data. While other nonlinear
corrections should be applied, the basic calculation for a given detector is, PI [keV] = PHA
[chan] * GAIN + OFFSET.
Gain/offset maps are not always produced during every observation, but the Swift Data Center
should collect the nearest map for each snapshot, and should include these maps in the “decb” file.
Layout. BAT gain/offset map. EXTNAME = ‘Gain Offset Map’