From ab03ec7ecec062c0f7cd84121c242690699a7038 Mon Sep 17 00:00:00 2001 From: Sandro Wenzel Date: Thu, 24 Sep 2026 21:12:36 +0200 Subject: [PATCH] Give the MFT support volume a name of its own This fixes a problem in the MFT support geometry, where a volume and its assembly share a name. - Volumes with the same name share a ROOT volume number, so consumers keyed on that number see only one of the two. - In FLUKA the pair collapsed to the assembly's placeholder material, which means BLCKHOLE, so the PEEK support disks deleted every particle entering them. --- Detectors/ITSMFT/MFT/base/src/Support.cxx | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/Detectors/ITSMFT/MFT/base/src/Support.cxx b/Detectors/ITSMFT/MFT/base/src/Support.cxx index 21f1ec2e0000e..856bb86c33c10 100644 --- a/Detectors/ITSMFT/MFT/base/src/Support.cxx +++ b/Detectors/ITSMFT/MFT/base/src/Support.cxx @@ -204,7 +204,8 @@ TGeoVolumeAssembly* Support::create(Int_t half, Int_t disk) // ======= Prepare support volume and add to HalfDisk ========= - auto* support_vol = new TGeoVolume(Form("Support_H%d_D%d", half, disk), localCS, mSupportMedium); + // a name of its own: a volume sharing a name with its assembly also shares its ROOT volume number + auto* support_vol = new TGeoVolume(Form("SupportVol_H%d_D%d", half, disk), localCS, mSupportMedium); auto* rot = new TGeoRotation("rot", 0, 0, 180); mHalfDisk->AddNode(support_vol, 0, rot);