Problem 43 - transportation of particle in large volume in the field
Summary: transportation of particle in large volume in the field
Status: RESOLVED WORKSFORME
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/transportation (show other problems)
Version: 1.0
Hardware: PC Linux
: P2 normal
Assignee: John Apostolakis
URL:
Depends on:
Blocks:
 
Reported: 1999-12-12 04:36 CET by liuht
Modified: 2000-01-24 11:13 CET (History)
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Description liuht 1999-12-12 04:36:01 CET 
I am working on AMS analysis, I use Geant4 to simulate the  +  cosmic ray
behaviar around the earth. It seems it can not trace out when I use the default
driver. I find it is beacause it calculate the peceision as
fDefault_Delta_Intersection_val/(the distance for next reaction); It will be
extreamly small when I want to trace the particle in the space and the particle
can hardly move. Which driver should I choose the cosmic study?
Comment 1 John Apostolakis 2000-01-24 11:13:59 CET 
In volumes where very large steps can happen,  we recommend that the logical
volume's "user limits" are used to limit the length of a single step (using the
maximum step length.)

Also the accuracy that is utilised can be set using the following method:

class G4PropagatorInField {
   ...
   // Sets both accuracies,
   //    maintaining a particular ratio Delta Interaction / OneStep )
   void    SetAccuraciesWithDeltaOneStep(G4double deltaOneStep);