Instructions for acquiring g-2 tracking code and bmad routines, and building executables

• Acquiring g-2 (and bmad) code.
• g-2/ directory tree
  • programs subdirectory - main program
  • code subdirectory - subroutines
  • files subdirectory - data files
  • plotting_scripts subdirectory - plotting_scripts
  • documentation subdirectory - plotting_scripts
• Executable
• Environment Variables
• Structures
• Bmad references. Includes links to BMAD manual, etc.
  

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  Acquisition Within Wilson Lab of code from the Wilson accelerator code repository

  
  
  1. If you have not done this already, make a directory for your local copy of the Bmad (g-2) distribution, programs, etc. Henceforth this directory will be referred to as < DIR >. A possible name might be: "root_dir". Substitute the appropriate directory name for " < DIR >" in the following steps.

  2. To make a local copy of a directory, the commands:
     

        cd < DIR >
        svn co https://accserv.lepp.cornell.edu/svn/<REPOS_PATH>.
     

     To find the correct < REPOS_PATH >, use the repository web viewer. For example. to make a local copy of the bmad library, use the commands:

     
       cd <DIR>
       svn co https://accserv.lepp.cornell.edu/svn/trunk/src/g-2
     

     This will create the directory <DIR>/g-2

  3. To update your local copy of a library and/or executable so that it has all the revisions that have been introduced into the repository, go to the directory containing the library and/or executable and use the command:
     

        svn update

  4. To compile the library: (see Environment Variables)
     

     cd <DIR>/g-2
     mk          # Produces production libraries and/or executables

     
     Or use "mkd" instead of "mk" if you want to the debug versions of the libraries and/or executables.
     

     Production libraries and executables are put in the directory:
     

     <DIR>/production
     

     and debug libraries and executables are put in:
     

     <DIR>/debug

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  g-2/ directory tree

  
  <DIR>/g-2
  CMakelists.txt - list of cmake files and cmake.g2_tracking - to build executable
  Subdirectories of g-2/ include: code  documentation   files   finalfocus   magneticfield   plotting_scripts  programs
  

  The executable is: g2_tracking  

  • /programs
    The main program tracking_master.f90 is here.
  • /code
    
    • Muon decay
      • DecayElectron.f90
      • MuonDecayInterface.f90 ---
      • compute_decayTime.f90 ----
      • muondecay.f90 ---
      • rotations.f90 ---
      • track_electron.f90 ---
      • transform_muon.f90 ---
    • Phase space
      • compute_moments.f90 --- Calculates average positions, standard deviations and corresponding twiss aprameters
      • create_phase_space.f90 ---
      • plot_twiss_data_mod.f90 ---
      • qp_read_twiss_data.f90 ---
      • twiss_propagate_cm.f90 ---
    • Magnetic fields
      • compute_derivatives.f90 ---
      • em_field_custom.f90 ---
      • em_field_custom_inj.f90 ---
      • em_field_interface.f90 ---
      • fieldMaps.f90 ---
      • fields.f90 --- Returns dipole and kicker magnetic fields and quadrupole electric fields as a function of position (and time for the kicker)
      • get_g2_fields_new.f90 ---
      • interpolate_field.f90 ---
      • magfield_interface.f90 ---
      • magfield_mod.f90 ---
      • quadratic_fit.f90 ---
      • read_field.f90 ---
      • sum_fields.f90 ---
    • Transfer matrices
      • create_taylor_ele.f90 ---
      • get_branch_inv_matrix.f90 ---
      • write_transfermatrix.f90 ---
      • get_quad_locs.f90 ---
    • Scattering
      • materials_mod.f90 ---
      • wall_hit_handler_custom.f90 ---
    • Optimization
      • optimize_incident.f90 ---
      • optimize_twiss.f90 ---
    • IO
      • create_gnu_input.f90 ---
    • Modules
      • muon_interface.f90 --- Subroutine interface blocks
      • muon_mod.f90 --- Structures defined
      • parameters_bmad.f90 --- Defines global parameters
    • Miscellaneous
      • rotate_ring.f90 ---
      • track1_custom.f90 ---
  • files/
    
    • Example --- File with prefix bmad is a lattice file that is parsed by the bmad_parser. The file defines the layout of the components of the injection line and ring, (quadrupoles, dipole, kicker) - lengths, strengths, location, also beam energy and initial twiss parameters. Also defined are the apertures for many of the elements. There are currently two branches. branch=0 corresponds to the injection line, from 30cm upstreadm
    • input.dat -- Initialization parameters: number of turns, number of muons, beam emittances, initial offsets (angles and displacements at the inflector exit with respect to the closed orbit.), inflector end coil scattering flag.
    • KICKER_E821.dat ---
    • KICKER_E989.dat ---
    • KICKER_E989_NoRolledEdges.dat ---
    • QUAD1_Long.dat ---
    • QUAD1_Short.dat ---
    • README.txt ---
    • bmad_short_wide_inf_ap_cor_tilt. ---
    • muons/ ---
  • plotting_scripts/
    
    • hist_initial_dist.gnu Plots histogram of initial distribution as it would appear with twiss parameteres at the inflector. Reads data from fort.22
    • hist_after_inflector.gnu Plots histogram of distribution that gets through inflector. Reads data from fort.23
    • hist_start_tracking.gnu Plots histogram of distribution at start of tracking in ring. Reads data from fort.24
    • hist_out.gnu Historam of distribution at the end of tracking
    • sigma.gnu (sigma_ps.gnu) Plots average and rms of distribution at the end of each turn. Data is in file fort.16
    • sigma_ele.gnu,sigma_ps_ele.gnu Plots average and rms of distribution at the end of each element (quad, dipole, kicker,...). (_ps_ is the version the creates a postscript output. Data is in file fort.26
    • lost_muons.gnu Plots number of muons surviving at each element. Data in fort.26. Written in compute_moments.f90
    • muons_vs_time.gnu Plots data from muons_vs_time.dat as a histogram of numbers of muons vs time
  • documentation/
    
    • Manual

    Executable

    • g2_tracking :

      Function: Generate and track a distribution of muons from the inflector, through the quad plates, kicker plates, passed pulsed kicker, around ring

      Output

      • input_data.dat --- All of the parameter values in the input namelist
      • fort.16 --- Averages and standard deviations of the phase space coordinates of the distrubution computed at the end of tracking for each turn. Includes <x>,<y>,<px>,<py>,<t>,<p>, and <(x-<x>)^2>, etc. and the number of muons remaining
        
      • fort.26 --- Same as fort.16 but computed at the end of tracking through each element
        
      • fort.19 --- Debug mode. If <nmuons> in the input.dat file is set to 1, then the phase space coordinates for that single trajectory at the end of tracking for each turn
        
      • fort.29 --- If <nmuons> in the input.dat file is set to 1, then the phase space coordinates for that single trajectory at the end of tracking for each element
        
      • muons_vs_time.dat --- Number of muons per unit time interval.
        
      • fort.22 --- Phase space coordinates of all muons in the initial distribution generated by subroutine create_phases_space
        
      • fort.23 --- Phase space coordinates of all muons in the distribution after passing through the inflector.
        
      • fort.24 --- Phase space coordinates of all muons at the start of tracking (after scattering in inflector end).
        
      • fort.25 --- Phase space coordinates of all muons at the end of tracking
        
      • VparamDependence (used to be fort.32) --- Summary of averages, standard deviations, lost particles at the end of tracking.
        
      • fort.33 --- Phase space coordinates of lost muons: muon #, s, vec(6), ele_name. For determining where muons are being lost
      • twiss_file.dat --- Twiss parameters of the ring. Initalized by g2twiss struct twiss values in input.dat file if "twiss at start" is commented out in tracking_master.
      • fort.51 --- Change in phase space coordinates due to scattering in upstream end of inflector
      • fort.52 --- Change in phase space coordinates due to scattering in downstream end of inflector
      • fort.53 --- Change in phase space coordinates due to scattering in wall_hit_handler
      • fort.71 --- Trajectory through injection channel. Computed when nmuons=1.
      • fort.72 --- Twiss parameters through injection channel. Computed along trajectory through injection channel when nmuons=1. (Not sure what initiaizes twiss)
      • gnu_input.dat --- Summary of data in input.dat that is read by plotting scripts

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    Environment Variables

    In order for the code to build and link various environment variables must be defined. They are for the most part telling the linker where to find the BMAD library subroutines. The easiest way to get these variables is on linux from your home directory to
    

    cp /home/dlr/.bashrc_g2 .bashrc
    

    Before you do this you might want to rename your own .bashrc file so that it is not overwritten and then combine the two.

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    Structures

    For reference
    The BMAD structures are defined in bmad_struct.f90
    The g-2 structures are defined in muon_mod.f90

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    References

    1. Inflector Acceptance and Twiss Parameters
    2. Matching Dispersion into the Ring June, 2013
    3. Tracking Through the Injection Channel April, 2013
    4. Inflector Acceptance June, 2012

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  Last modified: Sat Aug 23 12:43:23 EDT 2014