Problem 543

Summary:	problems with hadronic showers
Product:	Geant4	Reporter:	vacuum
Component:	processes/hadronic	Assignee:	Hans-Peter.Wellisch
Status:	RESOLVED FIXED
Severity:	major
Priority:	P2
Version:	other
Hardware:	PC
OS:	Linux

Description vacuum 2003-10-09 15:46:41 CEST

Dear Admin:

I have been encountering two problems when I run a particle shower initiated by
a given hadron. I am getting the energy, position, and time information for a
particle from steppingaction and trackingaction. My program is based on
exampleN04 given in Geant4.5.2. I have been running showers initiated by e-, e+,
gamma, proton, pi+, and pi-. I have done it for energies betwwen 10GeV and 100TeV.

Problem #1.

The time information for the hadrons gives 'inf' or 'nan' for some of the
daughter particles in the shower. This does not happen at 10GeV but for 100GeV
to 100TeV, this problem occurs for all the hadrons given above. It does not
happen for the leptons given above. I have noticed the daughter particles for
which the time information is lost, are almost at rest. Their kinetic energy is
about a few percent of their mass. It seems the problem is in dumping those
particle when they are about to stop.


PROBELM # 2. At 100 TeV, I the pi- initiated shower gives this error after
running for a few hours:


Unrecoverable error for:
 - Particle energy[GeV] = 19652.5
 - Material = Ice
 - Particle type = anti_lambda
GetHadronicProcess: No model found for this energy range

*** G4Exception: Aborting execution ***
./showans.exe: line 1: 15691 Aborted


BEST REGARDS.

Shahid

Comment 1 Hans-Peter.Wellisch 2003-10-14 05:05:59 CEST

Hi,

 problem 2 is simple: None of the physics lists distrobuted can do energies
above 14TeV.
As for problem 1, Michel may be able to aid you.

Many greetings,

Hans-Peter.

Comment 2 Hans-Peter.Wellisch 2003-12-09 06:50:59 CET

Hi, a precision problem in elastic scattering off hydrogen can lead to slightly
negative values for the kinetic energy, giving this effect.

Fix will be released in geant4 6.0.

Many greetings,

Hans-Peter.

Comment 3 vacuum 2003-12-09 14:51:59 CET

Hi Peter, thanks for the reply. About problem # 2, I was wondering if the next
geant release will have physics tables extrapolated to energies higher than
14TeV for the corresponding hasdrons (like kaons and anti-baryons)? And for
protons and pions, will it be extrapolated above a 100TeV?

Thanks alot.

Shahid