Astra Generator¶

Particle generation

In [1]:

# Useful for debugging
%load_ext autoreload
%autoreload 2

# Useful for debugging %load_ext autoreload %autoreload 2

In [2]:

from astra import AstraGenerator
import os

from astra import AstraGenerator import os

Point to template input file:

In [3]:

GENERATOR_IN = 'templates/dcgun/generator.in'

GENERATOR_IN = 'templates/dcgun/generator.in'

Make generator object:

In [4]:

G = AstraGenerator(input_file=GENERATOR_IN)
G.input

G = AstraGenerator(input_file=GENERATOR_IN) G.input

Out[4]:

{'fname': 'generator.part',
 'add': False,
 'n_add': 0,
 'ipart': 2000,
 'species': 'electrons',
 'probe': True,
 'noise_reduc': True,
 'cathode': True,
 'q_total': 0.1,
 'ref_zpos': 0,
 'ref_clock': 0,
 'ref_ekin': 1e-06,
 'high_res': True,
 'dist_x': 'r',
 'sig_x': 0.25,
 'c_sig_x': 5,
 'dist_px': 'g',
 'sig_px': 357.7,
 'c_sig_px': 5,
 'cor_px': 0,
 'dist_y': 'r',
 'sig_y': 0.25,
 'c_sig_y': 5,
 'dist_py': 'g',
 'sig_py': 357.7,
 'cor_py': 0,
 'dist_z': 'g',
 'sig_clock': 0.00849257,
 'c_sig_clock': 3,
 'dist_pz': 'g',
 'sig_ekin': 0.0005,
 'c_sig_ekin': 5}

Look at its input:

In [5]:

G.input

G.input

Out[5]:

{'fname': 'generator.part',
 'add': False,
 'n_add': 0,
 'ipart': 2000,
 'species': 'electrons',
 'probe': True,
 'noise_reduc': True,
 'cathode': True,
 'q_total': 0.1,
 'ref_zpos': 0,
 'ref_clock': 0,
 'ref_ekin': 1e-06,
 'high_res': True,
 'dist_x': 'r',
 'sig_x': 0.25,
 'c_sig_x': 5,
 'dist_px': 'g',
 'sig_px': 357.7,
 'c_sig_px': 5,
 'cor_px': 0,
 'dist_y': 'r',
 'sig_y': 0.25,
 'c_sig_y': 5,
 'dist_py': 'g',
 'sig_py': 357.7,
 'cor_py': 0,
 'dist_z': 'g',
 'sig_clock': 0.00849257,
 'c_sig_clock': 3,
 'dist_pz': 'g',
 'sig_ekin': 0.0005,
 'c_sig_ekin': 5}

Change some input:

In [6]:

G.input['ipart']= 999

G.input['ipart']= 999

Run:

In [7]:

G.verbose=True
G.run()

G.verbose=True G.run()

 --------------------------------------------------------------------------

                              generator              
                 Version 1.0 - macOS 64bit - Intel   
                        DESY,  Hamburg 2002          
                        Wed Aug  2 08:48:37 

     Working File is:    generator.in                                      
     Initializing        999      electrons
     including 6 probe particles at standard positions
     Particles start from a cathode
     Particles are quasi randomly distributed

          WARNING: Values could not be reached:
          Energy spread too high.
                  23 times standard correction procedure



     Final check:
     Particles taken into account      N =        999
     total charge                      Q =    -0.1000     nC
     horizontal beam position          x =    -7.8510E-07 mm
     vertical beam position            y =     6.2144E-06 mm
     longitudinal beam position        z =      0.000     m
     horizontal beam size          sig x =     0.2500     mm
     vertical beam size            sig y =     0.2500     mm
     longitudinal beam size        sig z =      0.000     mm
     total emission time               t =     5.0872E-02 ns
     rms emission time             sig t =     8.4198E-03 ns
     average kinetic energy            E =     1.0189E-06 MeV
     energy spread                    dE =     4.2521E-04 keV
     average momentum                  P =     1.0205E-03 MeV/c
     transverse beam emittance     eps x =     0.1736     pi mrad mm
     correlated divergence         cor x =     4.4093E-02 mrad 
     transverse beam emittance     eps y =     0.1750     pi mrad mm
     correlated divergence         cor y =     1.9513E-03 mrad
     longitudinal beam emittance   eps z =      0.000     pi keV mm
     correlated energy spread      cor z =      0.000     keV
     emittance ratio eps y/eps x         =     0.9922    

     phase-space distribution saved to file: generator.part                


     Generator ended with     1 warning(s)

Output is parsed as a ParticleGroup:

In [8]:

P = G.output['particles']

P = G.output['particles']

In [9]:

P.plot('x', 'y', figsize=(6,6))

P.plot('x', 'y', figsize=(6,6))

In [10]:

P.plot('t', 'pz', figsize=(6,6))

P.plot('t', 'pz', figsize=(6,6))

The input can be archived:

In [11]:

afile = G.archive()

afile = G.archive()

Archiving to file astra_generator_3edf607ef3e76f2846cd471aed6be637.h5

In [12]:

G2 = AstraGenerator.from_archive(afile)

G2 = AstraGenerator.from_archive(afile)

Check that the fingerprint is the same:

In [13]:

G2.fingerprint() == G.fingerprint()

G2.fingerprint() == G.fingerprint()

Out[13]:

True