acpostuma / simc_gfortran

SIMC - Physics Monte Carlo for Hall C and Hall A

simc_gfortran - Hall C/A Physics Monte Carlo

SIMC (simc_gfortran) is the standard Hall C Monte Carlo for coincidence reactions, written in FORTRAN.

SIMC has recently been modified to remove all explcit dependence on CERNLIB. There are now 3 ways to generate output for SIMC.

1. Run simc as normal (use "run_simc" script or interactively). This will generate a fortran ".bin" file in the worksim directory. Probably not too useful unless your analysis code is in fortran.

2. Run simc and then use the helper application to convert the default output to a PAW ntuple (NOTE: this WILL require use of cernlib - on the JLab machines type "setup cernlib/2005"). The helper application is in util/ntuple and must be compiled separately from simc. Running SIMC + the ntuple application can be done in one command using "run_simc_ntup".

3. Run simc and then use the helper application to convert the default output to a root tree (this program is also in fortran, but cernlib is not needed). The helper application is in util/root_tree and must also be compiled separately from simc. Running SIMC + the root-tree application can be done in one command using "run_simc_tree".

Features

• SIMC simulates the optics (using COSY models) and apertures of the Hall C spectrometers (HMS, SOS, SHMS) and other spectrometers at Jefferson Lab (HRS's, BigCal, ...)
• Radiative effects, multiple scattering, ionization energy loss and particle decay are included
• Simple presecriptions are available for Final State Interactions, Coulomb Corrections and other effects.

Reactions

SIMC has physics models for the following reactions.

• Elastic and quasi-elastic scatering: H(e,e'p), A(e,e'p)
• Exclusive pion production: H(e,e'pi+)n, A(e,e'pi+/-) (quasifree or coherent)
• Kaon electroproduction: H(e,e'K+)Lambda,Sigma, A(e,e'K+/-),A(e,e'K-)
• Semi-inclusive pion production: H(e,e'pi+/-)X, D(e,e'pi+/-)X
• Semi-inclusive kaon production: H(e,e'K+/-)X, D(e,e'K+/-)X
• Diffractive rho production: H(e,e'rho->pi+ pi-)p, D(e,e'rho->pi+ pi-)

SIMC is NOT

• Not a full detector response simulation a la GEANT/GEANT4
• Does NOT simulate a large class of processes simultaneously to gerate backgrounds (like Pythia for example)
• Not a generic event generator. Processes are generated over a limited phase space matching the spectrometer acceptances
• Not hard to modify

Overview

An overview of SIMC can be found in this presentation at the 2009 Hall A Collaboration Meeting

Documentation

For more information, see the SIMC Monte Carlo page in the Hall C Wiki