update the ITC cut to use pt1 time

This commit updates the ITC cut to use the pt1 time which is the ECA + PCA
without charge walk calibration time. The reason is that an event which is
mostly electronics noise may have all low charges which can't be calibrated
with the PCA walk calibration.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/dc.c b/src/dc.c
index 1882a0e..6d538b4 100644
--- a/src/dc.c
+++ b/src/dc.c
@@ -37,6 +37,11 @@
  *     number in any position of a 93 ns sliding window applied to the PMT time
  *     spectrum of the event.
  *
+ * Note: We use the pt1 time which is the ECA + PCA without the charge walk
+ * applied since the cut may fail to tag an event which consists mostly of
+ * electronics noise where the charges are too low to apply the PCA walk
+ * calibration.
+ *
  */
 int is_itc(event *ev)
 {
@@ -48,9 +53,9 @@ int is_itc(event *ev)
     nhit = 0;
     for (i = 0; i < MAX_PMTS; i++) {
         /* Only loop over hit PMTs with good calibrations. */
-        if (!ev->pmt_hits[i].hit || ev->pmt_hits[i].flags) continue;
+        if (!ev->pmt_hits[i].hit || ev->pmt_hits[i].pt1 < -10) continue;
 
-        t_array[nhit++] = ev->pmt_hits[i].t;
+        t_array[nhit++] = ev->pmt_hits[i].pt1;
     }
 
     /* Sort the times. */