Start Counter Background Studies
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Pure EM Background
- Generated 100K dummy events using
$ genphoton -M 100000 -Pmax 0.00001 -Pmin 0.000005 -Thetamin 0. -Thetamax 0.001 -o file_out.ascii
- Convert the ascii events into HDDM format and smear the z-vertex across the entire 30cm long target
NB: This step is not necessary as HDGEANT automatically smears the vertex across all three dimensions
$ genr8_2_hddm -V"0 0 50 80" file_out.ascii
- Use the following control.in file to process the events through HDGEANT (from latest sim-recon version) [3]
- The minimum energy for the photon beam was lowered to 1.2 MeV to look at hits contribution in SC from 50 MeV photons: BEAM 12. 9. 0.0012
- The background rate or flux for this minimum energy is 2.2e9 photons/s: BGRATE 2.2
- The photon pileup window is set to 100ns: BGGATE 0. 100.
- The following EM processes are turned on:
- Compton Scattering: COMP 1
- Pair Production: PAIR 1
- Energy Loss: LOSS 1
- Additional cuts in HDGEANT:
- The energy threshold in for hits in SC is 150 MeV (but is currently not applied in HDGEANT code)
- The time window for two hit resolution is 25 ns
- The hits are then smeared using mcsmear (???)
- To obtain the appropriate scaling factor for the plots, use the following approach:
where, is scaling factor, is the time window (BGGATE) in seconds, and is the number of events generated.
- This study was done for the nominal running luminosity of
- For the high luminosity running of , the BGRATE should be set to 11.0 instead of 2.2. One can either scale the above rates by applying an additional factor of
- Or, one can re-run the study with BGRATE set to 11.0. This "value will be scaled automaticaly
to the right value corresponding to the beam energy threshold defined by the BEAM card." - Sasha
Pure Hadronic Rates
- To study the pure hadronic
- GlueX Wiki » Start Counter » Start Counter Background Studies