Using SIMC

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SIMC repository and documentation

Brief Overview

  • SIMC main inputs are
 Beam energy , Spectrometers angles , Determination of which spectrometer detects electrons and which detects hadrons , 
 Target parameters (A,Z,density etc.) , Generator acceptance and resolution
  • The generator will generate events with the reaction 4 physical variables
 in-plane angle y' , out-of-plane angle x' , y(target) , momentum difference from central spectrometer momentum - delta
  • COSY simulation tool will generate the hrs_cosy file which include the transportation parameters for the particle along the spectrometer
  • The output of the simulation would be the 4 physical variables reconstructed at the focal plane of each spectrometer

How to run SIMC

  • compile SIMC directory: go to the SIMC directory, change what ever necessary in Makefile and type
  • create an input file under the directory infiles following the repository examples, e.g.
  • execute SIMC with an input file, e.g.
 (enter input file)> hrsr_eep_h
  • after the run was completed 4 output files are generated
 outfiles/hrsr_eep_h.geni  (information)
 outfiles/hrsr_eep_h.hist   (run settings)
 outfiles/hrsr_eep_h.gen   (output text file)
 worksim/hrsr_eep_h.rzdat   (paw ntuple)
  • convert the paw file into root
 cd worksim/
 h2root hrsr_eep_h.rzdat 
  • a root file hrsr_eep_h.root will now be generated in /worksim/.
  • The tree is called h666, and the most important variables are the reconstructed 4 variables (hs-electron arm, ss-hadron arm) and those generates (add an i), e.g.
 hsdelta ,  hsdeltai  ,hsytar ,  hsytari  ,hsyptar ,  hsyptari  , hsxptar ,  hsxptari
  • To draw, e.g. the difference between the generated and reconstructed momentum, use
 h666 -> Draw("hsdelta - hsdeltai")