Difference between revisions of "Start Counter Background Studies"

Revision as of 10:59, 21 June 2012

$ 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:

$f=1/\delta t/N$

where, $f$ is scaling factor, $\delta t$ is the time window (BGGATE) in seconds, and $N$ is the number of events generated.

This study was done for the nominal running luminosity of $10^{7}\gamma /s$
For the high luminosity running of $10^{8}\gamma /s$ , 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

$f_{{2}}=11.0/2.2$

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

@@ Line 22: / Line 22: @@
 *** Energy Loss: '''LOSS 1'''
 * Additional cuts in HDGEANT:
-** The energy threshold in for hits in SC is 150 MeV
+** 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 (???)
@@ Line 38: / Line 38: @@
 ** R vs Z hit [https://halldweb1.jlab.org/talks/2012-2Q/background/em_rz_1.png]
 ** Y vs X hit [https://halldweb1.jlab.org/talks/2012-2Q/background/em_yx_1.png]
+* This study was done for the nominal running luminosity of <math>10^7 \gamma/s</math>
+* For the high luminosity running of <math>10^8 \gamma/s</math>, 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
+<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 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