Problem 724 - Sharp peaks at 1 keV and 100 keV in neutron spectrum in LEP model
Summary: Sharp peaks at 1 keV and 100 keV in neutron spectrum in LEP model
Status: RESOLVED WONTFIX
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/util (show other problems)
Version: 7.0
Hardware: All All
: P2 normal
Assignee: Hans-Peter.Wellisch
URL:
Depends on:
Blocks:
 
Reported: 2005-02-18 18:28 CET by dennis.herbert.wright
Modified: 2005-07-05 06:52 CEST (History)
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Description dennis.herbert.wright 2005-02-18 18:28:47 CET 
Reported by LHCb and verified by D.H. Wright, there are two sharp peaks in the
neutron spectrum, a large one at 1 keV and a small one at 100 keV.  These are
due to negative energy protections in G4ReactionDynamics::TwoBody and
G4ReactionDynamics::Rotate.  The code lines causing the problem look like

      ekin = std::max( 1.0e-6, ekin );

Changing this to

      ekin = std::max(0.0, ekin );

for lines 2492 and 2501 in TwoBody removes the 100 keV line
and for lines 3007, 3036,  3067, 3108, 3127, 3147 in Rotate
removes the 1 keV line.
Comment 1 Hans-Peter.Wellisch 2005-07-05 06:52:59 CEST 
this is an intended model feature. It is usefull that the line shows up. It is
indicating that if this area of energies in relevant to a user, the model is
not appropriate.

Many greetings,

Hans-Peter.