From 900b2a11413f74cb5320ce936e0d7a8ed5a5824a Mon Sep 17 00:00:00 2001
From: Andreas Morsch <andreas.morsch@cern.ch>
Date: Tue, 2 Jun 2026 12:21:35 +0200
Subject: [PATCH 1/3] Add method isFromRadDecay(const int id). Checks whether
 particle results from radioactive decay in its history.

---
 Detectors/Base/include/DetectorsBase/Stack.h | 39 +++++++++++++++++++-
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/Detectors/Base/include/DetectorsBase/Stack.h b/Detectors/Base/include/DetectorsBase/Stack.h
index 69d221000e493..718122d5e3328 100644
--- a/Detectors/Base/include/DetectorsBase/Stack.h
+++ b/Detectors/Base/include/DetectorsBase/Stack.h
@@ -24,7 +24,8 @@
 #include "SimulationDataFormat/ParticleStatus.h"
 #include "Rtypes.h"
 #include "TParticle.h"
-
+#include "TVirtualMC.h"
+#include "TMCProcess.h"
 #include <map>
 #include <memory>
 #include <stack>
@@ -210,7 +211,7 @@ class Stack : public FairGenericStack
   /// query if a track is a direct **or** indirect daughter of a parentID
   /// if trackid is same as parentid it returns true
   bool isTrackDaughterOf(int /*trackid*/, int /*parentid*/) const;
-
+  bool isFromRadDecay(const int id);
   bool isCurrentTrackDaughterOf(int parentid) const;
 
   // returns the index of the currently transported primary
@@ -348,6 +349,40 @@ inline int Stack::getMotherTrackId(int trackid) const
   return mParticles[entryinParticles].getMotherTrackId();
 }
 
+inline bool Stack::isFromRadDecay(const int id)
+{
+  // Check whether particle originates directly or indirectly from radioactive decay
+  //
+  if (id < 0 || id >= static_cast<int>(mTrackIDtoParticlesEntry.size())) {
+    return false;
+  }
+  const auto entry = mTrackIDtoParticlesEntry[id];
+  if (entry < 0 || entry >= static_cast<int>(mParticles.size())) return false;
+  auto part = (mParticles[entry]);
+
+  // primary particle ?
+  if (part.getProcess() == 0 ) return false;
+  // particle directly from radioactive decay ?
+  if (part.getProcess() == kPRadDecay) {
+    return true;
+  }
+
+  // search in particle history
+  auto imo = mTrackIDtoParticlesEntry[part.getMotherTrackId()];  
+  auto isRad = false;
+  
+  while (imo > 0 ) {
+    auto mother = (mParticles[imo]);
+    if (mother.getProcess() == kPRadDecay) {
+      isRad = true;
+      break;
+    }
+    part = mother;
+    imo = mTrackIDtoParticlesEntry[mother.getMotherTrackId()];
+  }
+  return isRad;
+}
+
 inline bool Stack::isCurrentTrackDaughterOf(int parentid) const
 {
   // if parentid is current primary the answer is certainly yes

From 106d380b4766e93dc6fcc57811e9169e57de5fef Mon Sep 17 00:00:00 2001
From: Andreas Morsch <andreas.morsch@cern.ch>
Date: Tue, 2 Jun 2026 12:34:24 +0200
Subject: [PATCH 2/3] Fix formatting issue in Stack.h

---
 Detectors/Base/include/DetectorsBase/Stack.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Detectors/Base/include/DetectorsBase/Stack.h b/Detectors/Base/include/DetectorsBase/Stack.h
index 718122d5e3328..4eb7d2a59e762 100644
--- a/Detectors/Base/include/DetectorsBase/Stack.h
+++ b/Detectors/Base/include/DetectorsBase/Stack.h
@@ -368,9 +368,8 @@ inline bool Stack::isFromRadDecay(const int id)
   }
 
   // search in particle history
-  auto imo = mTrackIDtoParticlesEntry[part.getMotherTrackId()];  
+  auto imo = mTrackIDtoParticlesEntry[part.getMotherTrackId()];
   auto isRad = false;
-  
   while (imo > 0 ) {
     auto mother = (mParticles[imo]);
     if (mother.getProcess() == kPRadDecay) {

From f85bd6367455085cdd0a53b4f07aa1f03aa70053 Mon Sep 17 00:00:00 2001
From: Andreas Morsch <andreas.morsch@cern.ch>
Date: Tue, 2 Jun 2026 12:36:30 +0200
Subject: [PATCH 3/3] Fix formatting in Stack.h while loop condition

---
 Detectors/Base/include/DetectorsBase/Stack.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Detectors/Base/include/DetectorsBase/Stack.h b/Detectors/Base/include/DetectorsBase/Stack.h
index 4eb7d2a59e762..a893cdd4b7bc7 100644
--- a/Detectors/Base/include/DetectorsBase/Stack.h
+++ b/Detectors/Base/include/DetectorsBase/Stack.h
@@ -370,7 +370,7 @@ inline bool Stack::isFromRadDecay(const int id)
   // search in particle history
   auto imo = mTrackIDtoParticlesEntry[part.getMotherTrackId()];
   auto isRad = false;
-  while (imo > 0 ) {
+  while (imo > 0) {
     auto mother = (mParticles[imo]);
     if (mother.getProcess() == kPRadDecay) {
       isRad = true;