shadow4.sources.bending_magnet package

Submodules

shadow4.sources.bending_magnet.s4_bending_magnet module

Bending magnet magnetic structure.

class shadow4.sources.bending_magnet.s4_bending_magnet.S4BendingMagnet(radius=1.0, magnetic_field=1.0, length=1.0, emin=10000.0, emax=11000.0, ng_e=11, flag_emittance=0)[source]

Bases: BendingMagnet

Defines a shadow4 bending magnet magnetic structure.

Note that the radius and magnetic_field are somewhat redundant but they must be correctly set here. One can be calculated from the other if the electron energy is known (it is not known here). Shadow will use the magnetic_radius to sample the trajectory. The radius is positive in a typical ring (clockwise, e-). The sign of magnetic field indicates the direction of the arc: B>0 means x<0, and B<0 means x>0.

Parameters:

  • radius (float, optional) – Physical Radius/curvature of the magnet in m.

  • magnetic_field (float, optional) – Magnetic field strength (signed) in T.

  • length (float, optional) – physical length of the bending magnet (along the arc) in m.

  • emin (float, optional) – minimum photon energy in eV.

  • emax (float, optional) – maximum photon energy in eV.

  • ng_e (int, optional) – Number of points in energy.

  • flag_emittance (int, optional) – Flag: 0=Zero emmitance (filament beam), 1=Use emittance.

get_energy_box()[source]

Returns the limits of photon energy distribution for the source and the number of points.

Returns:

(emin, emax, npoints)

Return type:

tuple

get_info()[source]

Returns the specific information for the wiggler magnetic structure.

Return type:

str

classmethod initialize_from_magnetic_field_divergence_and_electron_energy(magnetic_field=1.0, divergence=0.001, electron_energy_in_GeV=1.0, emin=10000.0, emax=11000.0, ng_e=11, flag_emittance=0)[source]

Constructor from magnetic field divergence and electron energy.

Parameters:

  • magnetic_field (float, optional) – Magnetic field strength in T.

  • divergence (float, optional) – The accepted divergence in rad.

  • electron_energy_in_GeV (float, optional) – The electron beam energy in GeV.

  • emin (float, optional) – minimum photon energy in eV.

  • emax (float, optional) – maximum photon energy in eV.

  • ng_e (int, optional) – Number of points in energy.

  • flag_emittance (int, optional) – Flag: 0=Zero emmitance (filament beam), 1=Use emittance.

Return type:

instance of S4BendingMagnet

classmethod initialize_from_magnetic_radius_divergence_and_electron_energy(magnetic_radius=10.0, divergence=0.001, electron_energy_in_GeV=1.0, emin=10000.0, emax=11000.0, ng_e=11, flag_emittance=0)[source]

Constructor from magnetic radius, divergence and electron energy.

Parameters:

  • magnetic_radius (float, optional) – The magnetic radius in m.

  • divergence (float, optional) – The accepted divergence in rad.

  • electron_energy_in_GeV (float, optional) – The electron beam energy in GeV.

  • emin (float, optional) – minimum photon energy in eV.

  • emax (float, optional) – maximum photon energy in eV.

  • ng_e (int, optional) – Number of points in energy.

  • flag_emittance (int, optional) – Flag: 0=Zero emmitance (filament beam), 1=Use emittance.

Return type:

instance of S4BendingMagnet

is_monochromatic()[source]

Returns a flag indicating if the source is monochromatic (True) or polychromatic (False).

Return type:

boolean

set_energy_box(emin, emax, npoints=None)[source]

Sets a box for photon energy distribution for the source.

Parameters:

  • emin (float) – minimum photon energy in eV.

  • emax (float) – maximum photon energy in eV.

  • npoints (int, optional) – Number of points in energy.

set_energy_monochromatic(emin)[source]

Sets a single energy line for the source (monochromatic).

Parameters:

emin (float) – photon energy in eV.

to_python_code()[source]

Returns the python code for defining the bending magnet magnetic structure.

Returns:

The python code.

Return type:

str

shadow4.sources.bending_magnet.s4_bending_magnet_light_source module

Bending magnet light source.

class shadow4.sources.bending_magnet.s4_bending_magnet_light_source.S4BendingMagnetLightSource(name='Undefined', electron_beam=None, magnetic_structure=None, nrays=5000, seed=12345)[source]

Bases: S4LightSource

Defines a bending magnet light source and implements the mechanism of sampling rays.

Parameters:

  • name (str, optional) – The name of the light source.

  • electron_beam (instance of ElectronBeam) – The electron beam parameters.

  • magnetic_structure (instance of S4BendingMagnet) – The shadow4 bending magnet magnetic structure.

  • nrays (int, optional) – The number of rays.

  • seed (int, optional) – The Monte Carlo seed.

calculate_spectrum(photon_energy_array=None, shift_half_interval=0, output_file='')[source]

Calculates the spectrum.

Parameters:

  • photon_energy_array (None, numpy array, optional) – The array with the photon energy values (in eV) for calculating the spectrum. If None, it uses the emin, emax and ng_e from the magnetic structure.

  • shift_half_interval (int, optional) – For photon_energy_array=None, set this to 1 to shift the energy points a half-energy-interval (must be uniform) to mimic histogramming arrays.

  • output_file (str, optional) – Name of the file to write the spectrom (use “” for not writing file).

Returns:

(e, f, w) numpy arrays with photon energy (e), photon flux (f) and spectral power (w).

Return type:

tuple

get_beam(F_COHER=0, psi_interval_in_units_one_over_gamma=None, psi_interval_number_of_points=1001, sample_emission_cone_in_horizontal=1)[source]

Creates the beam as emitted by the bending magnet.

Parameters:

  • F_COHER (int, optional) – A flag for coherent (1) or incoherent (0) rays.

  • psi_interval_in_units_one_over_gamma (int, optional) – The sampling interval for the vertical divergence in units if 1/gamma. If None, it is calculated automatically.

  • psi_interval_number_of_points (int, optional) – The number of points for the vertical divergency scan.

Return type:

instance od S4beam

get_info()[source]

Returns the specific information for the bending magnet light source.

Return type:

str

get_pdf()[source]

Returns the probability distribution function used to sample radiation angles and photon energy.

Returns:

(tot_intensity, s_intensity, p_intensity, angle_array_mrad, photon_energy_array) - tot_intensity, s_intensity, p_intensity : if monochromatic source: 1D arrays (vs) angle

if polychromatic source: @D arrays (vs) angle, energy

  • angle_array_mrad: 1D array

  • photon_energy_array: 1D array if polychronatic source else None.

Return type:

tuple

to_python_code(**kwargs)[source]

Returns the python code for calculating the bending magnet source.

Returns:

The python code.

Return type:

str

Module contents