FREQ_MAP
The main program and sample initialization files are in "/dlr/development/freq_map". To run type "$ACC_EXE/freq_map".
  • Description: Compute phase space coordinates vs trajectory starting amplitude for each of N turns.
  • The parameters that characterize the scan are given in an input file. An example of an input file is "$ACC_SRC/bsim/freq_map/freq_map_example.in" 
    ¶meters
    Qx = 0.53              !horizontal tune
    Qy = 0.59              !vertical tune
    Qz = -0.1              !synchrotron tune
    x0 = 0.0               !minimum horizontal starting amplitude
    y0 = 0.0               !minimum vertical starting amplitude 
    x1 = 0.02              !maximum horizontal starting amplitude
    y1 = 0.01              !maximum vertical starting amplitude
    e0 = 0.                !minimum energy offset
    e1 = 0.001             !maximum energy offset
    dx = 0.002             !horizontal step size
    dy = 0.002             !vertical step size
    de = 0.0005            !energy step size
    lat_file = '/cdat/cesr38/disk1/dlr/bmad_devel/6wigs/bmad_3_18_03.lat' !lattice file
    n_turn = 100           !number of turns
    particle = 1           !species (1=positrons, -1=electrons)
    i_train = 1            !train of particle being tracked
    j_car = 1              !car of tracked particle
    n_trains_tot = 9       !number of trains in strong beam
    n_cars = 4             !number of cars in each train
    current = 1.           !current in strong beam bunches (mA)
    lrbbi = .true.         !include long range parasitic interactions
    beambeam_ip = .false.  !do not include main beambeam interaction
    close_pretz = .false.  !do not close pretzel (set horizontal diff disp at IP to 0)
    close_vert = .false.   !do not close vertically at IP
    go = .true.            !do not tune manually
/
  • The data is written to files "INPUT_FILENAME.out". The output file consists of 12 columns of data 
    1 x-coordinate at the start of tracking
2 y-coordinate at the start of tracking
3 fractional energy offset at the start of tracking
4 Qx(first half) - horizontal tune based on fft of horizontal displacements of turns 0-n/2
5 Qy(first half) - vertical tune based on fft of vertical displacements of turns 0-n/2
6 Qz(first half) - synchrotron tune based on fft of longitudinal displacements of turns 0-n/2
7 Qx(second half) - horizontal tune based on fft of horizontal displacements of turns 0-n/2
8 Qy(second half) - vertical tune based on fft of vertical displacements of turns 0-n/2
9 Qz(second half) - synchrotron tune based on fft of longitudinal displacements of turns 0-n/2
10 Delta Qx - (Qx(first half) - Qx(second-half))
11 Delta Qy - (Qy(first half) - Qy(second-half))
12 Delta Qz - (Qz(first half) - Qz(second-half))
    In our example that would be "freq_map_example.out". To plot the data "/home/dlr/development8_linux/plot_freq_map"