;+
; NAME:
; KILLAPE
;
; PURPOSE:
; This routine removes Adjacent Photon Events (APEs) from a MJF block
; of HBR PTI data. An APE is defined as two photons occurring in adjacent
; 8 usec bins ACROSS sequential HBR data words. Namely, the first photon
; occurs in time bin 9 and the second photon occurs in time bin 0 of the
; next word. These events occur in the HBR PTI data for roughly 3-4% of
; all photons lying in time bin 0 or 9. They are considered UNPHYSICAL
; due to the deadtime of the detector (>16 usec) and the consistent
; occurrance of these events ONLY across sequential HBR data words.
;
; CATEGORY:
; HEAO HBR.
;
; CALLING SEQUENCE:
;
; KILLAPE, PTIblock, Fixes
;
; INPUTS:
; PTIblock: Structure variable holding the next MJF block of PTI data.
; It is one of the outputs of the READPTI routine.
;
; OUTPUTS:
; Fixes: This structure variable holds the corrected time intervals.
; Its tags are defined as follows:
;
; nAPE: The number of APEs found in this MJF block.
; hAPE: Array of indices pointing to elements in the orginal
; Photon Time Interval array, PTIblock.PTI where APEs
; were found. (= -1 if nAPE=0).
; pti: The corrected PTIs with APEs removed and neighboring
; PTIs corrected. (= -1 if no photons in MJF block).
;
; PROCEDURE:
; This routine first finds any APEs by determining which PTIs = 1
; occur across adjacent HBR data words. The PTIs corresponding to any
; APEs found are marked and later removed. The neighboring PTIs before
; and after the APEs are subsequently corrected by adding a 1 to the
; smaller of the two PTIs. If the two PTIs are equal, then the 1 goes to
; the PTI before the APE. This algorithm leads to a roughly equal
; distribution of corrections before and after the APEs.
;
; EXAMPLE:
;
; OPENPTI, lu, !DATA_PATH+'086_7_7.xdr' ; Open a HBR PTI data file
; READPTI, lu, block ; Read in a MJF block
; KILLAPE, block, fixes ; Remove APEs
;
; h = hist1d( fixes.pti, MIN=0, MAX=100 )
; plot,h,psym=10,xrange=[0,100]
;
; COMMON BLOCKS:
; DEF_HBRH: Holds all the MJF and MNF PTI pointers, (see def_hbrh.pro).
;
; MODIFICATION HISTORY:
; Written by: Han Wen, September 1995.
; 09-OCT-1995 Return short integer for fixes.nAPE instead of long integer
;-
pro KILLAPE, PTIblock, Fixes
common def_hbrh
; Define default values for the Fixes structure
hAPE = -1
nAPE = 0
pti = -1
; Extract the time interval from the start of a NON-zero MNF
; to the first photon
nMNF = N_ELEMENTS(PTIblock.mnfh)/16
i=-1
repeat begin
i = i+1
n = PTIblock.mnfh(mnfptr_.mnfndt,i)
endrep until (n gt 0) or (i eq (nMNF-1))
if (n eq 0) then goto, DEFAULT
pti0 = PTIblock.mnfh(mnfptr_.delbeg,i)
if (pti0 lt 0) then pti0 = 65536L + pti0 ; Check for overflows
; Find all adjacent photons
pti = PTIblock.PTI
here = where(pti eq 1,nadj)
if (nadj eq 0) then goto, DEFAULT
; Adjacent Photon Events (APEs) ONLY occur across HBR data words,
; i.e. bins 9 and 0.
ts = lonarr(nadj)
for k=0L,nadj-1L do $
ts(k) = pti0 + TOTAL(pti(0:here(k)))
bins = ts MOD 10
h0 = where( bins eq 0, nAPE)
if (nAPE eq 0) then goto, DEFAULT
; First mark the APEs for later removal
here0 = here(h0)
pti(here0) = -9999
; Then correct the neighboring PTIs by adding 1 to the smaller/equal
; of the two intervals. This will result in a more/less equal distribution
; of corrections before and after these APEs.
left = pti(here0-1) ; PTIs neighboring to the LEFT of APEs
right= pti(here0+1) ; " " " " RIGHT " "
hR = where(right lt left,nR) ; See where RIGHT PTIs are < LEFT PTIs
if (nR gt 0) then $
pti(here0(hR)+1) = pti(here0(hR)+1) + 1
hL = where(right ge left,nL) ; See where LEFT PTIs are <= RIGHT PTIs
if (nL gt 0) then $
pti(here0(hL)-1) = pti(here0(hL)-1) + 1
if (nR+nL) ne nAPE then $
message,'nR+nL <> nAPE:'+strtrim(nR+nL,2)+','+strtrim(nAPE,2)
hAPE = here0
nAPE = nAPE
here = where( pti ne -9999,nne)
pti = pti(here)
; Pack up the fixes and send them back to the USER
DEFAULT:
fixes = { $
nAPE : fix(nAPE), $
hAPE : hAPE, $
pti : pti }
end