Updated neutron background simulation

[civanch]

For geant4 simulation of neutron background effects for muon system a special simulation required when time window is extended to 0.1 second and all tracking cuts used in normal CMS simulation are disabled. This part of simulation is revised and improved:

1. removed double instantiation of muon-nuclear interaction
2. update EM physics configuration for Geant4 10.2
3. disabled all tracking cuts
4. added option enabling thermal neutron scattering (E < 4 eV)
5. updated custom fragments for this simulation

All these modifications should not change mainstream SIM step but should help making Muon TDR

[cmsbuild]

A new Pull Request was created by @civanch (Vladimir Ivantchenko) for CMSSW_9_0_X.

It involves the following packages:

SimG4Core/Application
SimG4Core/PhysicsLists

@cmsbuild, @civanch, @mdhildreth, @davidlange6 can you please review it and eventually sign? Thanks.
@makortel this is something you requested to watch as well.
@davidlange6, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[civanch]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/17944/console Started: 2017/02/23 19:41

[cmsbuild]

+1
Tested at: 1522ed2
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17621/17944/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17621/17944/summary.html

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @smuzaffar

[davidlange6]

Hi @civanch - are there some slides/graphs showing the validation done so far?

[civanch]

@davidlange6 , muon peoples are trying to run just now to see effects of these modifications (not obvious how long this will take for them). What I have checked myself: neutron HP and neutron HP thermal models are really enabled and the code is running without crashes. I also run standard ttbar without these neutron and it is fine to me. The mainstream should not be affected.

[davidlange6]

+1