j_cor_position

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

Table: 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

Table: 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