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Bradley, Great work. Is this cut unique for Mollers or similar thing may be in the trident generator. Stepan On 5/13/16 3:25 AM, Bradley T Yale wrote: > > I think I found the real problem with how the Moller generator was > initially set up. > > This one affects the generated distribution a LOT more than the RNG > precision probably did, and explains the remaining strangeness in the > generated distribution. > > > Looking at the egs5 Moller procedure, the angular cut was defined as: > > > abs(v(np)) > 0.010 radians > > > where v(np) is supposed to be theta. > > However, the variables u, v, and w in egs are actually *directional > cosines*, p_x = p*u, p_y = p*v, and p_z = p*w. > > > So this means that in reality, the generator was saving Moller events > such that > > abs [ sin(theta)*sin(phi) ] > 0.010 > > > which has a periodic nature to it. Plot this equation for some value > of phi (or just think about it) and you'll see what was likely making > these strange hills and gaps in the energy distribution - full-wave > rectified Mollers! > > > The scattered beam simulation does correctly define theta though: > sqrt[ u^2 + v^2 ] > > I made a moller_v3 procedure with this correction (still with a >10 > mrad cut), and the comparison between before and after is shown. > The generated events now agree with the calculated cross section (XS > curve is shown on the 'bad' plot), and no apparent missing events. > > These will be run through recon to see if we can finally get good > Moller agreement with data. > I'm also going to try changing the scattered beam energy cut shown in > the software meeting to see if it fixes Tim's phi vs. energy discrepancy. > -Brad > > ------------------------------------------------------------------------ > > 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 > ######################################################################## 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