1. C&A 21 Aug 06 1 A Monte Carlo Puzzle, for the SCG Toby Burnett University of Washington

2. C&A 21 Aug 06 2 Switch to “standard” Multiple scattering/Energy loss Motivation: we are using an old, obsolete version of G4’s multiple scattering algorithm, and we should periodically evaluate our PSF with both versions Here is all we have to do: G4Generator.mscatOption = false; My observation, based on GR v9r7: CPU time increases by a factor almost 2!

3. C&A 21 Aug 06 3 A few details: who is the culprit? From the log file: first line is our standard, second with latest G4 code. G4Generator:exe... INFO Time User : Tot= 54.5[min] Ave/Min/Max=0.654(+- 3.09)/ 0/ 43.6 [s] #=5000 G4Generator:exe... INFO Time User : Tot= 45.9[min] Ave/Min/Max=0.551(+- 2.64)/ 0/ 51.9 [s] #=5000 Tkr:execute INFO Time User : Tot= 16.8[min] Ave/Min/Max=0.766(+- 1.41)/ 0/ 10.8 [s] #=1313 Tkr:execute INFO Time User : Tot= 46.6[min] Ave/Min/Max= 2.12(+- 10.5)/ 0/ 239 [s] #=1318 TkrDigiAlg:execute INFO Time User : Tot= 73.9 [s] Ave/Min/Max= 14.8(+- 119)/ 0/5.36e+003 [ms] #=5000 TkrDigiAlg:execute INFO Time User : Tot= 36.8[min] Ave/Min/Max= 442(+-5.24e+003)/ 0/2.32e+005 [ms] #=5000 Top:execute INFO Time User : Tot= 77.7[min] Ave/Min/Max=0.932(+- 3.64)/ 0/ 48.2 [s] #=5000 Top:execute INFO Time User : Tot= 133[min] Ave/Min/Max= 1.59(+- 12.3)/ 0/ 494 [s] #=5000

4. C&A 21 Aug 06 4 Is it the multiplicity? current replacement It seems not!. Good luck!