With Pass 8, event_types are introduced. Even though these are essentially a generalization of conversion_type (i.e., front vs back converting events) in that the event types partition the data into distinct subclasses which have their own effective area, point spread, and energy dispersion functions, in Pass 8, there are alternative partitions for a given class. For example, the Pass 8 SOURCE class selection can be partitioned in one of three ways: into front vs back converting events, into events belonging to one of 4 "PSF" subclasses, or into events belonging to one of 4 "EDISP" classes.
The Pass 8 event_class and event_type descriptions and usage are described in the following links.
The event type partition has been added as an option for gtobssim. Examples for P8_SOURCE_V5:
gtobssim irfs=P8_SOURCE_V5 evtype=none gtobssim irfs=P8_SOURCE_V5 evtype=PSF gtobssim irfs=P8_SOURCE_V5 evtype=EDISP |
evtype=none is the default, in which case the application will use the front/back partition, consistent with pre-Pass 8 behavior.
For evtype=[PSF,EDISP], DSS keywords specifying the event_type partition that was used will be written to the FT1 files that are produced. These keywords will show the bit pattern that would be used to mask to obtain the corresponding partition, e.g., for evtype=PSF:
DSTYP2: BIT_MASK(EVENT_CLASS,128,P8) DSUNI2: DIMENSIONLESS DSVAL2: 1:1 DSTYP2: BIT_MASK(EVENT_TYPE,60,P8) DSUNI2: DIMENSIONLESS DSVAL2: 1:1 |
Here 60 = 0b111100, the binary representation of the mask with bits 2-5 set. Note that the event_type DSS keywords will be omitted for the front/back partition.
For both evclass and evtype, the user must specify the integer corresponding to bit-mask that selects the desired events within a single partition:
gtselect evclass=128 evtype=3 # P8_SOURCE_V5, front and back (i.e., all) events gtselect evclass=128 evtype=1 # P8_SOURCE_V5, front-only events gtselect evclass=128 evtype=60 # P8_SOURCE_V5, PSF[0-3] (all) events gtselect evclass=256 evtype=960 # P8_CLEAN_V5, EDISP[0-3] (all) events |
The evtype=[3,60,960] selections all return all of the events, but they also specify the irfs corresponding to the event_type partition selected. This information is written to the DSS keywords and read by downstream tools.
The output will be expanded to indicate event_type partitions:
$ gtirfs P8_CLEAN_V5 ( = P8_CLEAN_V5::BACK + P8_CLEAN_V5::FRONT ) P8_CLEAN_V5 (EDISP) ( = P8_CLEAN_V5::EDISP0 + P8_CLEAN_V5::EDISP1 + P8_CLEAN_V5::EDISP2 + P8_CLEAN_V5::EDISP3 ) P8_CLEAN_V5 (PSF) ( = P8_CLEAN_V5::PSF0 + P8_CLEAN_V5::PSF1 + P8_CLEAN_V5::PSF2 + P8_CLEAN_V5::PSF3 ) P8_CLEAN_V5::BACK P8_CLEAN_V5::EDISP0 P8_CLEAN_V5::EDISP1 P8_CLEAN_V5::EDISP2 P8_CLEAN_V5::EDISP3 P8_CLEAN_V5::FRONT P8_CLEAN_V5::PSF0 P8_CLEAN_V5::PSF1 P8_CLEAN_V5::PSF2 P8_CLEAN_V5::PSF3 P8_SOURCE_V5 ( = P8_SOURCE_V5::BACK + P8_SOURCE_V5::FRONT ) P8_SOURCE_V5 (EDISP) ( = P8_SOURCE_V5::EDISP0 + P8_SOURCE_V5::EDISP1 + P8_SOURCE_V5::EDISP2 + P8_SOURCE_V5::EDISP3 ) P8_SOURCE_V5 (PSF) ( = P8_SOURCE_V5::PSF0 + P8_SOURCE_V5::PSF1 + P8_SOURCE_V5::PSF2 + P8_SOURCE_V5::PSF3 ) P8_SOURCE_V5::BACK P8_SOURCE_V5::EDISP0 P8_SOURCE_V5::EDISP1 P8_SOURCE_V5::EDISP2 P8_SOURCE_V5::EDISP3 P8_SOURCE_V5::FRONT P8_SOURCE_V5::PSF0 P8_SOURCE_V5::PSF1 P8_SOURCE_V5::PSF2 P8_SOURCE_V5::PSF3 P8_ULTRACLEAN_V5 ( = P8_ULTRACLEAN_V5::BACK + P8_ULTRACLEAN_V5::FRONT ) P8_ULTRACLEAN_V5 (EDISP) ( = P8_ULTRACLEAN_V5::EDISP0 + P8_ULTRACLEAN_V5::EDISP1 + P8_ULTRACLEAN_V5::EDISP2 + P8_ULTRACLEAN_V5::EDISP3 ) P8_ULTRACLEAN_V5 (PSF) ( = P8_ULTRACLEAN_V5::PSF0 + P8_ULTRACLEAN_V5::PSF1 + P8_ULTRACLEAN_V5::PSF2 + P8_ULTRACLEAN_V5::PSF3 ) P8_ULTRACLEAN_V5::BACK P8_ULTRACLEAN_V5::EDISP0 P8_ULTRACLEAN_V5::EDISP1 P8_ULTRACLEAN_V5::EDISP2 P8_ULTRACLEAN_V5::EDISP3 P8_ULTRACLEAN_V5::FRONT P8_ULTRACLEAN_V5::PSF0 P8_ULTRACLEAN_V5::PSF1 P8_ULTRACLEAN_V5::PSF2 P8_ULTRACLEAN_V5::PSF3 $ |