Objective
Measure the probability for incident proton to create gamma (>30-50 MeV) in MMS without a signal in ACD, to be compared with the results of simulations. These gammas would be unrecognizable background. How can it happen: proton interacts in MMS such a way that gammas from pi_0 go toward LAT, and all other charged secondaries miss the ACD or create there underthreshold signals. It is clear that the probability of this case quickly goes down with increase of incident proton energy - higher multiplicity and higher energy of secondaries. This background could be important for diffuse gamma radiation especially extragalactic
Experimental Set-up
MMS in front of the instrument, with ACD tile behind it. 5 GeV normal incidence proton beam. needed statistics ~ 1M protons. Possible to increase the thickness of MMS (say have there 4 layers) to increase the effect
Trigger
external beam trigger. Should be clean and free from "empty" triggers
Data Taking Configurations
In the
Predictions from MC Simulations
In the
Possible Experimental Backgrounds
In the attachmen