From b1023a2afab5ff4a6a41ac581ddec8a7c1fa375c Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Tue, 17 Dec 2019 15:39:16 -0600
Subject: [PATCH] Correction to the check location for partial intersections
 with tets at the end of a track.

---
 src/mesh.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mesh.cpp b/src/mesh.cpp
index f421f23001..7f451c8f2c 100644
--- a/src/mesh.cpp
+++ b/src/mesh.cpp
@@ -1711,7 +1711,8 @@ UnstructuredMesh::bins_crossed(const Particle* p,
   // tally remaining portion of track after last hit if
   // the last segment of the track is in the mesh
   if (hits.back().first < track_len) {
-    tet = get_tet(last_r + u * (track_len + hits.back().first) / 2.0);
+    auto pos = (last_r + u * hits.back().first) + u * ((track_len - hits.back().first) / 2.0);
+    tet = get_tet(pos);
     if (tet) {
       bins.push_back(get_bin_from_ent_handle(tet));
       lengths.push_back((track_len - hits.back().first) / track_len);