Alex, The delay of the shower initiation for gammas is already accounted for in the formula you are using (contains a +/- term for gammas/electrons). If you do it again, it will double-count. I really don't think it is worth trying to be this precise with the effective shower profile formula. It has effective quantities for Z and the critical energy E_c which are only approximations to the much more complex behavior being simulated in the MC. I would not trust the analytical formula to better than a few percent. The MC is much more precise because it does the exact integral numerically. Richard Jones Alex Dzierba wrote: > Hi Beni > > Thanks for your observation and I should of course take the effect into > account - I will. But - it will make things worse because now I > consistently > underestimate the deposition in layer 1 and overestimate in layer 2 > (assuming the simulations are correct) and this will be even more the > case when I properly distribute the start of the shower into the > calorimeter. > > Cheers > Alex > > > At 12:37 PM -0400 6/8/07, beni zihlmann wrote: >> Hi Alex, >> when you do the analytical calculation you are assuming that the >> shower starts >> right at the beginning of layer 1. correct? In the simulation the >> shower will >> begin usually inside layer one or even deeper. This might be one of >> the reasons for >> the discrepancy. >> >> cheers, >> Beni >> >> >> B. Zihlmann >> Indiana University >> Physics Department >> 727 E. Third Street >> Bloomington, IN 47405 >> phone: (812) 855 6973 >> Fax: (812) 855-5533 > >
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