OpticalElement

class marxs.optics.OpticalElement(**kwargs)

Bases: SimulationSequenceElement

Base class for all optical elements in marxs.

This class cannot be used to instanciate an optical element directly, rather it serves as a base class from with other optical elements will be derived.

At the very minumum, any derived class needs to implement __call__ which typically calls intersect and either process_photon or process_photons. If the interaction with the photons (e.g. scattering of a mirror surface) can be implemented in a vectorized way using numpy array operations, the derived class should overwrite process_photons (process_photon is not used in this case). If no vectorized implementation is available, it is sufficient to overwrite process_photon. Marxs will call process_photons, which (if not overwritten) contains a simple for-loop to loop over all photons in the array and call process_photon on each of them.

Define a new MARXS element.

Attributes Summary

display	Dictionary for display specifications, e.g. color.
pos4d

Methods Summary

__call__(photons)	Call self as a function.
process_photon(dir, pos, energy, polarization)	Simulate interaction of optical element with a single photon.
process_photons(photons, intersect, ...)	Simulate interaction of optical element with photons - vectorized.

Attributes Documentation

display = {}

Dictionary for display specifications, e.g. color

pos4d

Methods Documentation

__call__(photons)

Call self as a function.

process_photon(dir, pos, energy, polarization)

Simulate interaction of optical element with a single photon.

This is called from the process_photons method in a loop over all photons. That method also collects the output values and inserts them into the photon list. process_photon can return any number of values in additon to the required dir, pos, etc.. Define a class attribute output_columns as a list of strings to determine how into which column these numbers should be inserted.

Parameters:

dirnumpy.ndarray

4-d direction vector of ray in homogeneous coordinates

posnumpy.ndarray

4-d position of last interaction pf the photons with any optical element in homogeneous coordinates. Together with dir this determines the equation of the ray.

energyfloat

Photon energy in keV.

polarizationfloat

Polarization angle of the photons.

Returns:

dirnumpy.ndarray

4-d direction vector of ray in homogeneous coordinates

posnumpy.ndarray

4-d position of last interaction pf the photons with any optical element in homogeneous coordinates. Together with dir this determines the equation of the ray.

energyfloat

Photon energy in keV.

polarizationfloat

Polarization angle of the photons.

probabilityfloat

Probability that the photon passes this optical element. Set to 0 if the photon is absorbed, to 1 if it passes and to number between 0 and 1 to express a probability that the photons passes.

otherfloats

One number per entry in output_columns.

process_photons(photons, intersect, interpos, intercoos)

Simulate interaction of optical element with photons - vectorized.

Derived classes should overwrite this function or process_photon.

Parameters:

photons: `astropy.table.Table` or `astropy.table.Row`

Table with photon properties

intersectarray

Boolean array marking which photons should be processed by this element.

interpos, intercoosarray (N, 4)

The array interpos contains the intersection points in the global coordinate system, intercoos in a local coordiante system (2d in most cases).

Returns:

photons: astropy.table.Table or astropy.table.Row

Table with photon properties. If possible, the input table is modified in place, but in some cases this might not be possible and the returned Table may be a copy. Do not rely on either - use photons.copy() if you want to ensure you are working with an independent copy.