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Cyclotron

Cyclotron

Last edited by Jochem Snuverink
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Goal

Here we will run the Cyclotron flavour of OPAL (OPAL_cycl) in three distinct modes

  1. tune calculation
  2. accelerated orbit mode
  3. 3D space charge calculation

Preparation

This example is for OPAL 2.0.x and 1.6.x (see compatible versions in examples). If you do not have already access to OPAL, you can visit the download page the download page. In case OPAL is on your cluster please check with the administrator how to use. PSI user please click here.

Needed Input Files

For this project we need input files, that you obtain by clicking on links below:

  1. cyclotron1.in and cyclotron2.in (cyclotron1.in and cyclotron2.in for 1.6.x) the OPAL input files
  2. bfield.dat (magnetic field map)
  3. rffield1.dat and rffield2.dat (rf field maps)
  4. dist1.dat dist2.dat (the input distributions)
  5. ic.dat (initial conditions for the tune calculation)
  6. refsol.dat (the reference solution for the tune calculation)
  7. cyclotron1.gpl and cyclotron2.gpl (cyclotron2.gpl for 1.6.x) (plotting scripts for gnuplot)

Tune Calculation using cyclotron1.in

Needed files: cyclotron1.{in,bash,gpl}, bfield.dat, dist1.dat, ic.dat & refsol.dat

For the tune calculation we need initial conditions (ic): energy, radius and radial momenta given to us by an other program in the file ic.dat. The Bash script cyclotron1.bash will run the tune calculation for all energies specified in ic.dat and store the radial and vertical tune values together with reference data. Make sure the script has execute permission (chmod u+x cyclotron1.bash). A comparison can be plotted with gnuplot, by executing

gnuplot cyclotron1.gpl

The result is saved in cyclotron1.pdf and shown below.

Accelerated Orbit Calculation using cyclotron2.in

Needed files: cyclotron2.{in,gpl}, bfield.dat, dist2.dat, rffield1.dat & rffield2.dat

For this calculation the initial conditions are set in the input file. Run OPAL with

opal cyclotron2.in | tee cyclotron2.out

where you also save the output in cyclotron2.out. It is always a good idea to check the standard output of OPAL in order to reveal problems.

gnuplot cyclotron2.gpl

As in the previous example, the result is saved in cyclotron2.pdf and shown below.

3D space charge calculation

Under construction

In cyclotron2.in, only the distribution and beam command, together with the field solver needs to be adapted.

Dist1 as defined here

Dist1:DISTRIBUTION, DISTRIBUTION=GAUSS

sigmax=3E-3, sigmapx=1E-5,

sigmay=3E-3, sigmapy=1E-5,

sigmat=3E-3, sigmapt=1E-5,

CORRX = 0, CORRY =0, CORRT = 0;

represents a beam with 3 mm rms. The field solver Fs1 is the standard open domain FFT solver:

Fs1:FIELDSOLVER, FSTYPE=FFT, MX=64, MY=64, MT=64, PARFFTX=true, PARFFTY=true, PARFFTT=false, BCFFTX=open, BCFFTY=open, BCFFTT=open;

and the beam is represented by 1E5 macro particles

Beam1: BEAM, PARTICLE=PROTON, pc=P0, NPART=1E5, BCURRENT=1.0E-6, CHARGE=1.0, BFREQ= f1;