fix the fts cut

This commit fixes the FTS cut so that it returns 1 when the event is flagged as
failing the cut. Previously, the function returned the following:

not enough PMT pairs: 0 (fail)
median time > 6.8 ns: 0 (fail)
otherwise:            1 (pass)

This had two issues: the return value wasn't consistent with the rest of the
data cleaning cuts and it should pass if there aren't enough PMT pairs.

Now, I fixed the not enough PMT pairs case and made the return value consistent
with the rest of the data cleaning cuts:

not enough PMT pairs: 0 (pass)
median time > 6.8 ns: 1 (fail)
otherwise:            0 (pass)

2 files changed, 4 insertions, 4 deletions

diff --git a/src/dc.c b/src/dc.c
index 7b5b1d7..8b85070 100644
--- a/src/dc.c
+++ b/src/dc.c
@@ -106,7 +106,7 @@ int is_fts(event *ev)
             /* Get the absolute value of the time difference. */
             dt = fabs(ev->pmt_hits[i].t - ev->pmt_hits[j].t);
 
-            if (dt <= 25.0 && distance < 300.0) {
+            if (dt <= FTS_DT_THRESH && distance < FTS_DIST_THRESH) {
                 deltat_array[count++] = dt;
                 if (count >= MAX_PAIRS) goto end;
             }
@@ -118,7 +118,7 @@ end:
     if (count > FTS_COUNT_THRESH) {
         gsl_sort(deltat_array,1,count);
         dtmedian = gsl_stats_median_from_sorted_data(deltat_array,1,count);
-        return dtmedian < FTS_MEDIAN_CUT;
+        return dtmedian > FTS_MEDIAN_CUT;
     }
 
     return 0;
diff --git a/utils/plot-energy b/utils/plot-energy
index 1e8cbcb..3c645d5 100755
--- a/utils/plot-energy
+++ b/utils/plot-energy
@@ -205,7 +205,7 @@ if __name__ == '__main__':
 
     if prompt_plus_muons.size and follower.size:
         # require Michel events to pass more of the SNO data cleaning cuts
-        michel = follower[follower.dc & (DC_JUNK | DC_CRATE_ISOTROPY | DC_QVNHIT | DC_FLASHER | DC_NECK | DC_ESUM | DC_OWL | DC_OWL_TRIGGER | DC_FTS) == DC_FTS]
+        michel = follower[follower.dc & (DC_JUNK | DC_CRATE_ISOTROPY | DC_QVNHIT | DC_FLASHER | DC_NECK | DC_ESUM | DC_OWL | DC_OWL_TRIGGER | DC_FTS) == 0]
 
         michel = michel[michel.nhit >= 100]
 
@@ -242,7 +242,7 @@ if __name__ == '__main__':
 
     if prompt.size and follower.size:
         # neutron followers have to obey stricter set of data cleaning cuts
-        neutron = follower[follower.dc & (DC_JUNK | DC_CRATE_ISOTROPY | DC_QVNHIT | DC_FLASHER | DC_NECK | DC_ESUM | DC_OWL | DC_OWL_TRIGGER | DC_FTS) == DC_FTS]
+        neutron = follower[follower.dc & (DC_JUNK | DC_CRATE_ISOTROPY | DC_QVNHIT | DC_FLASHER | DC_NECK | DC_ESUM | DC_OWL | DC_OWL_TRIGGER | DC_FTS) == 0]
         neutron = neutron[~np.isnan(neutron.ftp_x) & ~np.isnan(neutron.rsp_energy)]
         r = np.sqrt(neutron.ftp_x**2 + neutron.ftp_y**2 + neutron.ftp_z**2)
         neutron = neutron[r < AV_RADIUS]