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I have not used the GS distribution in egs5 and I have found the following comment in egs5_mscat.f, ! GS multiple scattering distribution. Optional, ! and kinetic energy must be less than 100 MeV. The GS distribution in EGS5 may not work at our energy. -----Original Message----- From: Bradley T Yale [mailto:[log in to unmask]] Sent: Wednesday, October 14, 2015 3:00 PM To: Maruyama, Takashi; Solt, Matthew Reagan Cc: hps-software Subject: Re: Large-Angle FEE Discrepancy in MC Hey Takashi (and maybe Sho), I'm trying to implement the GS distribution in egs5, as referenced in the last email. I set IGSDST=1 in (a copy of) esa.inp, and usegsd(i) = 1 in the .f program that gets executed, but get an error: namelist read: variable not in namelist apparent state: unit 25 named pgs5job.pegs5inp last format: list io lately reading sequential formatted external IO Abort The 'IGSDST' variable should be the one being referenced above, unless I'm mistaken. I included that in the same place as 'IRAYL' and 'IMPACT' in the esa.inp file, which gets linked as pgs5job.pegs5inp. Is there anything else I could be missing? I am not familiar with namelist. If I get this to work, I'll make scattered tungsten/carbon beam with it so that the large angle behavior can be compared with the old way (and data). By the way, Geant4 does not use Moliere by default, but Lewis theory to handle MS, which is even more elaborate. So we should probably at least switch this on to handle interactions inside the target, where MS is more important. This could turn out to not have much of an effect when running at higher energies though, so whether it's worth doing is up for debate. ________________________________________ From: Maruyama, Takashi <[log in to unmask]> Sent: Wednesday, October 14, 2015 2:23 PM To: Bradley T Yale; Solt, Matthew Reagan Cc: hps-software Subject: RE: Large-Angle FEE Discrepancy in MC Thank you, Bradley for useful information. It turns out that Geant4 v10 has several Coulomb scattering models. It might be worth checking it out as well. Takashi -----Original Message----- From: Bradley T Yale [mailto:[log in to unmask]] Sent: Wednesday, October 14, 2015 11:04 AM To: Maruyama, Takashi; Solt, Matthew Reagan Cc: hps-software Subject: Large-Angle FEE Discrepancy in MC Concerning what I mentioned in the meeting about how egs5 handles multiple scattering by default: Page 91 (109 of the attached pdf) describes how the default Moliere distribution breaks down for large angles and high Z, and page 367 (385 of the attached pdf) gives the flag for using the Goudsmit-Saunderson instead. Figure 2 of http://www2.cose.isu.edu/~tforest/Classes/NucSim/Day7/MSC_Fernandez_NIM_B73_pg447-473_1993.pdf <http://www2.cose.isu.edu/~tforest/Classes/NucSim/Day7/MSC_Fernandez_NIM_B73_pg447-473_1993.pdf> Shows the large-angle difference between Moliere and G-S for lower energy and an Au target, so there could be a similar effect for us. I started to try out the G-S distribution a while back in /u/group/hps/production/mc/egs5/src/esa-carbon-GS.inp but decided not to alter things to that extent. Maybe it would be worth trying for this purpose though. ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the HPS-SOFTWARE list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1