This notebook was created by Mykola Veremchuk (mykola.veremchuk@xfel.eu), Svitozar Serkez. Source and license info is on GitHub. June 2019.
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import numpy as np
import logging
from ocelot import *
from ocelot.rad import *
from ocelot.optics.wave import dfl_waistscan, screen2dfl, RadiationField
from ocelot.gui.dfl_plot import plot_dfl, plot_dfl_waistscan
from ocelot import ocelog
ocelog.setLevel(logging.ERROR) #suppress logger output
In [2]:
# Activate interactive matplolib in notebook
import matplotlib
%matplotlib inline
# Setup figure white background
matplotlib.rcParams["figure.facecolor"] = (1,1,1,1)
# Setup figure size
matplotlib.rcParams['figure.figsize'] = [10, 10]
See 9_synchrotron_radiation.ipynb tutorial first, reproducing the 2d visualization
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# generating 2D synchrotron radiation (it will take about 1-3 minutes)
und = Undulator(Kx=0.43, nperiods=500, lperiod=0.007, eid="und")
lat = MagneticLattice(und)
beam = Beam()
beam.E = 2.5 # beam energy in [GeV]
beam.I = 0.1 # beam current in [A]
screen_2d = Screen()
screen_2d.z = 100.0 # distance from the begining of lattice to the screen
screen_2d.size_x = 0.002 # half of screen size in [m] in horizontal plane
screen_2d.size_y = 0.002 # half of screen size in [m] in vertical plane
screen_2d.nx = 51 # number of points in horizontal plane
screen_2d.ny = 51 # number of points in vertical plane
screen_2d.start_energy = 7761.2 # [eV], starting photon energy
screen_2d.end_energy = 7761.2 # [eV], ending photon energy
screen_2d.num_energy = 1 # number of energy points[eV]
screen_2d = calculate_radiation(lat, screen_2d, beam)
to convert SR from Screen to RadiationField there is a function:
dfl = screen2dfl(screen, polarization='x')
screen: Screen object, electric field of which will be used to generate RadiationFieldpolarization: polarization for conversion to RadiationField ($E_x$ or $E_y$)
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dfl_2d = screen2dfl(screen_2d, polarization='x')
2D (monochromatic) RadiationFied generated from Screen
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plot_dfl(dfl_2d,
fig_name='dfl_2d generated from screen_2d',
column_3d=1)
Let's study the radiation back-propagated to the middle of the undulator
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plot_dfl(dfl_2d.prop_m(-100-3.5/2, m=0.02, return_result=1),
fig_name='dfl_2d at waist position')
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# generating 3D synchrotron radiation (it will take up to 5 minutes as 75*75*20=112k datapoints are calculated)
screen_3d = Screen()
screen_3d.z = 100.0 # distance from the begining of lattice to the screen
screen_3d.size_x = 0.002 # half of screen size in [m] in horizontal plane
screen_3d.size_y = 0.002 # half of screen size in [m] in vertical plane
screen_3d.ny = 50
screen_3d.nx = 50
screen_3d.start_energy = 7720 # [eV], starting photon energy
screen_3d.end_energy = 7790 # [eV], ending photon energy
screen_3d.num_energy = 25 # number of energy points[eV]
screen_3d = calculate_radiation(lat, screen_3d, beam)
dfl_3d = screen2dfl(screen_3d, polarization='x')
In this way we obtain a 3D RadiationFied distribution in space-frequency domain
Note the spatial dependence on the photon energy. The slice values of x=0 and y=0 are provided as well as on-axis spectrum
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plot_dfl(dfl_3d,
domains='sf',
fig_name='dfl_3d in space-frequency domain',
slice_xy=True) # bool type variable, if True, slices will be plotted; if False, projections will be plotted
Transverse projections and integrated spectrum
In [9]:
plot_dfl(dfl_3d,
domains='sf',
fig_name='dfl_3d in space-frequency domain',
slice_xy=False)
Plotting in space-time domain yields pulse duration that is approximately the radiation wavelength (fundamental harmonic) times number of undulator periods ~ 0.08um.
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plot_dfl(dfl_3d,
domains='st',
fig_name='dfl_3d in space-time domain',
slice_xy=False)
Radiation distribution in the middle of the undulator
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plot_dfl(dfl_3d.prop_m(-100-3.5/2, m=0.02, fine=1, return_result=1),
domains='fs',
fig_name='dfl_3d at waist position in frequency-space domains',
slice_xy=False)
Because of the rapidly-oscilalting phase, plotting in the far zone in not possible yet, to be solved in the future
In [12]:
plot_dfl(dfl_3d,
domains='fk',
fig_name='dfl_3d at waist position in inverse space-frequency domains',
slice_xy=False)
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