From 9bb1faffac3dd739c95d38a85008b49c5269c138 Mon Sep 17 00:00:00 2001
From: Whitney Armstrong <warmstrong@anl.gov>
Date: Thu, 21 Jan 2021 14:17:38 -0600
Subject: [PATCH] 	modified:   src/SiTrackerEndcap_geo.cpp

---
 src/SiTrackerEndcap_geo.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/SiTrackerEndcap_geo.cpp b/src/SiTrackerEndcap_geo.cpp
index 4e91b7e..59c9140 100644
--- a/src/SiTrackerEndcap_geo.cpp
+++ b/src/SiTrackerEndcap_geo.cpp
@@ -193,7 +193,12 @@ static Ref_t create_detector(Detector& description, xml_h e, SensitiveDetector s
       ++ring_num;
     }
   }
-  pv = motherVol.placeVolume(assembly);
+  // hack to get around the way ACTS defines pos/neg endcaps based on zposition 
+  Position final_pos(0,0,0);
+  if(reflect) {
+    final_pos = Position(0,0,-1.0e-9);
+  }
+  pv = motherVol.placeVolume(assembly,final_pos);
   pv.addPhysVolID("system",det_id);
   sdet.setPlacement(pv);
   return sdet;
-- 
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