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j_cor_position
converts detector positions corrected for microstrip plate irregularities into
absolute values (mm from centre of detector).
Event positions are randomized within the pixel designated by the two
event telemetry values RAWX and RAWY, and given as floating point values in
columns DETX and DETY of JMXi-****-COR.
If an event falls in an area where
the position determination is known to be bad, then a flag is raised
in the STATUS column of the relevant -COR extension. Bad areas of
the detector are signaled in the correction table extensions by having
one or both position values equal to 1000.0 plus the corrected
position value.
The possible values of STATUS are given in the Table 41
Table 41:
Possible corrected event STATUS values
|
|
Value |
Meaning |
0 |
Event good for all analysis purposes |
4 |
Events fall on anode segment with a dead anode in the
calibration area (currently 4th anode on JEM-X 2) |
8 |
Event has uncertain time correlation |
16 |
Event comes from an anode regarded as bad |
32 |
Event comes from position next to a bad anode |
64 |
Bad energy due to poor detector gain history determination |
128 |
Bad energy determination due to event position |
256 |
Bad
position determination |
512 |
Bad
position determination |
1024 |
Possibly leaked event from a calibration source |
2048 |
Event detected before SETUP at beginning of Science Window |
4096 |
Event from outside active area of detector |
8192 |
Event coming from known hotspot on detector |
As you see these STATUS values are the powers of 2. If events are failed in more
then one
way then STATUS is equal to the sum of the corresponding values, the back
reconstruction has
no problems and rise no ambiguity.
Events that fail in one or more ways can still be
used for some purposes: binned spectra don't require good position
determinations; uncertainties in gain determination don't affect sky images etc.
Therefore each program here after can select all the events that are appropriate
for making high quality science data products with the best possible statistics.
The content of the corrected data structures for the different data modes is
given in Table 42
Table 42:
Content of JMXi-****-COR Data Structures.
|
|
Column Name |
Description |
JMXi-FULL-COR |
DETX |
Corrected
location of the event on the detector |
DETY |
Corrected
location of the event on the detector |
PI |
Pulse Invariant energy of the event |
STATUS |
`Goodness' of the corrected events |
JMXi-REST-COR |
DETX |
Corrected
location of the event on the detector |
DETY |
Corrected
location of the event on the detector |
REST_PI |
Pulse Invariant energy of the event |
STATUS |
`Goodness' of the corrected events |
JMXi-RATE-COR |
RATE_CORR |
Corrected count rate |
STATUS |
`Goodness' of the data |
JMXi-SPTI-COR |
PI |
Pulse Invariant energy of the event |
STATUS |
`Goodness' of the corrected events |
JMXi-SPEC-COR |
SPEC_CORR |
Corrected Counts in the 64 PI channels |
STATUS |
`Goodness' of the corrected spectra |
The TIME data do not have a -COR data structure, as the on-board time is
calculated at ISDC during the Data Preparation, so the corrected
TIME events are in JMXi-TIME-PRP
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