Problem 1695

Summary: Time of Products from Nuclear Muon Capture are too short
Product: Geant4 Reporter: a.edmonds
Component: processes/hadronic/stoppingAssignee: Vladimir.Ivantchenko
Status: RESOLVED FIXED    
Severity: major    
Priority: P5    
Version: 10.0   
Hardware: PC   
OS: Linux   
Attachments: Plot of proton arrival times from nuclear muon capture on aluminium
Plot of proton arrival times from nuclear muon capture on aluminium (after patch)
Patch to fix the time of nuclear capture products

Description a.edmonds 2014-12-01 19:50:09 CET
Created attachment 297 [details]
Plot of proton arrival times from nuclear muon capture on aluminium

Hi

I'm having problems with the timing of products from nuclear muon capture in Geant4.10.00.p02.

My simulation fires muons at an aluminum target and there is a sensitive detector volume separately that records anything emitted from it. However, the global arrival time of these protons is much too short when compared to the muonic atom lifetime (864ns). I've attached a plot to show the actual arrival times.

I'm using physics list QGSP_BERT.hh, which uses G4StoppingPhysics which then uses G4MuonMinusCapture.

From a little bit of debugging myself it seems that the random time generated by G4MuonMinusCapture is not used for the nuclear cascade but is used for the decay.
Comment 1 a.edmonds 2014-12-02 10:55:44 CET
Hi

So, Vladimir Ivantchenko has provided me a patch for this. I've attached both the patch and a plot showing that arrival times are closer to what we expect.

Many thanks
Andy
Comment 2 a.edmonds 2014-12-02 10:56:12 CET
Created attachment 298 [details]
Plot of proton arrival times from nuclear muon capture on aluminium (after patch)
Comment 3 a.edmonds 2014-12-02 10:56:58 CET
Created attachment 299 [details]
Patch to fix the time of nuclear capture products