parthitf -- Remove particle events from FGS photomultiplier counts.
parthitf infile inmask outtable sigma0 sigma threshold hitval inttime
Data in groups PMTXA, PMTXB, PMTYA, and PMTYB are photomultiplier (PMT) counts from the Fine Guidance Sensor (FGS). Parthitf will remove particle events, that is, pixels of high counts, from PMT groups.
Mean and standard deviations are calculated for all points in a group having values higher than that of threshold. If a pixel value is higher than the mean by sigma0 times the standard deviation, it is considered to be a particle event, and will be assigned the value of hitval. After the first round of removals, mean and standard deviations are recalculated using the remaining points--particle events are again located using these new values. This process continues until no more points are removed. Statistics about particle events are calculated and put in the output table.
The program produces an output table with the following columns:
COLUMN NAME CONTENTS ----------- -------- OBSID Observation ID ASTMODE FGS observation mode FGSID FGS ID number PMTXA_NOHIT, PMTXB_NOHIT, Number of particle events in each PMT PMTYA_NOHIT, PMTYB_NOHIT PMTXA, PMTXB, PMTYA, PMTYB Mean counts in each PMT after particle count removal PMTXA_STD, PMTXB_STD, Standard deviations of each PMT after PMTYA_STD, PMTYB_STD particle count removal PMTXA_HIT, PMTXB_HIT, Mean counts of particle counts in each PMT PMTYA_HIT, PMTYB_HIT PMTXA_HITF, PMTXB_HITF, Particle event frequencies in each PMT PMTYA_HITF, PMTYB_HITF (per second) ANGLE_A, ANGLE_B Mean values of theta A and B angles, i.e., average of 'SSENCA' and 'SSENCB' STD_A, STD_B Standard deviation of theta A and B angles SIGMA0 Statistical criterion of particle event removal in first iteration SIGMA Statistical criterion of particle event removal in subsequent iterations
1. Remove particle events for input files yparthitf$infile.d1h and yparthitf$infile.d2h with corresponding mask files yparthitf$inmask.m1h and yparthitf$inmask.m2h. Write results to the table xparthitf$output.tab. Points that are 2.5 standard deviations above average will be regarded as particle events during the first iteration (3 standard deviations above average in subsequent iterations). Neglect points with mask value below 0.5. Integration time is 25 milliseconds (the default value) in each pixel, and the mask value 0 will be assigned to the particle event pixels:
fg> parthitf (infile = "yparthitf$infile.d![1-2]h", \ >>> inmask = "yparthitf$inmask.m![1-2]h", \ >>> outtable = "xparthitf$output", sigma0 = 2.5, sigma = 3, \ >> threshold = 0.5, hitval = 0, inttime = 0.025)