update how neck events are flagged

This commit updates the is_neck_event() function to include the requirement
that 50% of the normal PMTs in the event must have z <= -425.0.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/dc.h b/src/dc.h
index f613b93..102e47f 100644
--- a/src/dc.h
+++ b/src/dc.h
@@ -33,6 +33,12 @@
 #define DC_OWL_TRIGGER    0x100
 #define DC_FTS            0x200
 
+/* Height of PMTs which are considered to be at the "bottom" of the detector
+ * for the neck cut. Comes from the SNOOP definition of a neck event in SNO. */
+#define NECK_BOTTOM_HEIGHT -425.0
+/* Fraction of normal PMT hits which must be below NECK_BOTTOM_HEIGHT. */
+#define NECK_BOTTOM_FRACTION 0.5
+
 /* Delta-t threshold for PMT pairs in the FTS cut (ns). */
 #define FTS_DT_THRESH 25.0
 /* Distance threshold for PMT pairs in the FTS cut (cm). */