1. T. Burnett C&A 31 July 06 Study of the G4 stepping cut value Toby Burnett and Anthony Nardozza (senior physics student) Are the results at all sensitive to the value(s)? Can we optimize to save CPU time? There has only been one study, by Richard, a long time ago.

2. T. Burnett C&A 31 July 06 Reference It is described in the Physics Reference Manual, http://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides/PhysicsReferen ceManual/print/PhysicsReferenceManual71.pdf http://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides/PhysicsReferen ceManual/print/PhysicsReferenceManual71.pdf Default is 1 mm

3. T. Burnett C&A 31 July 06 Details All-gamma (18MeV- 180 GeV) source GlastRelease v9r7 UW physics Condor farm 200 runs of 5000 incident (1M) for each setting

4. T. Burnett C&A 31 July 06 CPU, accepted difference nominal

5. T. Burnett C&A 31 July 06 Cut=0.01 mmCut=1.4 mm Representative Psf fits

6. T. Burnett C&A 31 July 06 Summary CPU time: no gain Small (1%) effect on accepted rate needs to be understood, compared with beam test perhaps No apparent effect on PSF