Difference between revisions of "Start Counter Background Studies"
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<math>f_{2} = 11.0/2.2</math> | <math>f_{2} = 11.0/2.2</math> | ||
− | * Or, one can re-run the study with BGRATE set to 11.0. This "value will be scaled | + | * Or, one can re-run the study with BGRATE set to 11.0. This "value will be scaled automatically to the right value corresponding to the beam energy threshold defined by the BEAM card." - Sasha |
− | to the right value corresponding to the beam energy threshold defined by the BEAM card." - Sasha | + | |
+ | * The plots after applying the above scaling factor are: | ||
+ | ** Rates [https://halldweb1.jlab.org/talks/2012-2Q/background/em_paddle_2.png] | ||
+ | ** R vs Z hit [https://halldweb1.jlab.org/talks/2012-2Q/background/em_rz_2.png] | ||
+ | ** Y vs X hit [https://halldweb1.jlab.org/talks/2012-2Q/background/em_yx_2.png] | ||
+ | |||
=== Pure Hadronic Rates === | === Pure Hadronic Rates === | ||
− | * To study the pure hadronic | + | * To study the pure hadronic rates, a similar method is used compared to the EM background study. |
+ | * 395K background events are generated using '''bggen'''. The bggen card options are: [https://halldweb1.jlab.org/talks/2012-2Q/background/hadronic_bggen_run.ffr] | ||
+ | * These events are then passed through HDGEANT | ||
+ | ** The BGRATE and BGGATE options are turned off as we don't want to look at photon pile-up | ||
+ | ** No EM processes options are turned on | ||
+ | ** The BEAM options are still '''BEAM 12. 9. 0.0012''' | ||
+ | ** The output is again smeared using mcsmear | ||
+ | * No normalization factor is applied | ||
+ | * The following rates are observed: | ||
+ | ** Rates [https://halldweb1.jlab.org/talks/2012-2Q/background/had_paddle_1.png] | ||
+ | ** Hit Multiplicity [https://halldweb1.jlab.org/talks/2012-2Q/background/had_mult_1.png] | ||
+ | ** R vs Z hit [https://halldweb1.jlab.org/talks/2012-2Q/background/had_rz_1.png] | ||
+ | ** Y vs X hit [https://halldweb1.jlab.org/talks/2012-2Q/background/had_yx_1.png] | ||
Revision as of 11:19, 21 June 2012
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 automatically to the right value corresponding to the beam energy threshold defined by the BEAM card." - Sasha
Pure Hadronic Rates
- To study the pure hadronic rates, a similar method is used compared to the EM background study.
- 395K background events are generated using bggen. The bggen card options are: [11]
- These events are then passed through HDGEANT
- The BGRATE and BGGATE options are turned off as we don't want to look at photon pile-up
- No EM processes options are turned on
- The BEAM options are still BEAM 12. 9. 0.0012
- The output is again smeared using mcsmear
- No normalization factor is applied
- The following rates are observed:
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