Problem 1133

Summary:	Unphysical neutron production using HP model
Product:	Geant4	Reporter:	Joel Long <jllong>
Component:	processes/hadronic	Assignee:	tkoi
Status:	RESOLVED INVALID
Severity:	major
Priority:	P2
Version:	9.3
Hardware:	Apple
OS:	Mac OS X
Attachments:	My impossible output

Description Joel Long 2010-08-05 19:05:18 CEST

Firing 14.1 MeV neutrons into Copper produces a variety of non-physical reactions with both Cu-63 and Cu-65. I am using HadronPhysicsLHEP_Preco_HP (the HP model should be handling the 14.1 MeV neutrons). 

I have attached a copy of my run, along with my physics list, but here are a few of the observed reactions:

Cu65 + n -> Cu62 + 2n (2 nucleons lost)
Cu63 + n -> Cu65 + n (2 nucleons gained)
Cu63 + n -> Cu66 (2 nucleons lost)

Information about the projectile and secondaries was retrieved from G4Step and its associated data. Target information is retrieved from G4IsoParticleChange. Normally, the reaction information in G4IsoParticleChange is not required to match the actual reaction (the production model added to the process is allowed to generate the G4IsoParticleChange however it sees fit), but I did not add a production model. Based on my examination of G4HadronicProcess, in the absence of a production model the target particle is passed to the isoparticlechange from the process. 

I have not yet had a chance to test for this problem in other operating environments, materials, or energy ranges.

Comment 1 Joel Long 2010-08-05 19:14:01 CEST

Created attachment 87 [details]
My impossible output

Comment 2 tkoi 2010-09-03 02:58:56 CEST

Hi,

By historical reason, NeutronHP selects target nucleus indecently from upper level framework. 
So I do not believe your method can correctly get target nucleus.

>>Cu65 + n -> Cu62 + 2n (2 nucleons lost)
I think maybe the correct target is Cu63
>>Cu63 + n -> Cu65 + n (2 nucleons gained)
I think maybe the correct target is Cu65
>>Cu63 + n -> Cu66 (2 nucleons lost)
I think maybe the correct target is Cu65
And there is no charge number brake.  (Please correct me, if I miss understand)

I checked by myself that 14.1 MeV neutron hits single isotope target of Cu63 or Cu65.
And there is no event in which break baryon number conservation is broken for 1 k incidences. 

So please try different ways and if you still have a trouble, then please let me know.

Tatsumi

P.S. I will change the status of this report from “ASSIGNED” to “RESOLVED-INVALID” soon.

Comment 3 tkoi 2010-09-24 03:05:15 CEST

I do not receive any response, but it already passed more than two weeks.
I change the status “RESOLVED-INVALID”.

Tatsumi