ElementsOnTorus

class marxs.design.rowland.ElementsOnTorus(**kwargs)

Bases: ParallelCalculated, OpticalElement

A collection of elements on a Rowland torus.

When initialized, it places elements in the space available on the Rowland torus, most commonly, this class is used to place grating facets.

After generation, individual facet positions can be adjusted by hand by editing the attributes elem_pos or elem_uncertainty. See marxs.simulation.Parallel for details.

After any of the elem_pos, elem_uncertainty or uncertainty is changed, generate_elements needs to be called to regenerate the facets on the GAS.

Parameters:

rowlandmarxs.design.rowland.RowlandTorus

Torus on which the elements are placed.

d_elementlist of two floats

Size of the edge of elements along the two (y and z in canonical marxs orientation) edges. d_element can be larger than the actual size of the silicon membrane or the active area of a CCD chip to accommodate a minimum thickness of the surrounding frame.

guess_distancefloat

A ray can intersect a torus in up to four points. guess_distance specifies the starting distance for the numerical search for the intersection point to resolve this ambiguity. Default is the start close to outer rim of the torus.

optimize_axisnp.array

Homogeneous coordinate of the axis along which elements will be moved. This will usually coincide with the optical axis of the telescope. Default is the x-axis in the coordinate system of the torus.

normal_specnp.array or callable

see ParallelCalculated for details. Default for this class: Pointing inward into the Rowlandtorus, as one would do for an array of e.g. CCDs.

parallel_specnp.array or callable

see ParallelCalculated for details. Default for this class: Symmetry axis of the torus.

Define a new MARXS element.

Methods Summary

elempos()	Generate 3D positions of elements
elemposyz()	Specify the element position in the yz plane

Methods Documentation

elempos()

Generate 3D positions of elements

For each element, y and z coordinates in the torus coordinate system are generated from self.elemposyz and the elements are placed at x=0. Then, that initial coordinate is transformed into the global coordinate system and moved by self.guess_distance * self.optimize_axis. The resulting position is the starting point for numerical optimization along self.optimize_axis to find the on-torus location.

elemposyz()

Specify the element position in the yz plane

For the torus, the Rowland circle lies in the xy plane and the symmetry axis of the torus is the y-axis. In this class, the position of the elements is specified in the yz plane in the coordinates of the torus and the remaining coordinate.

This function will be customized by derived classes.

Returns:

ypos, zposnp.array

1D arrays of y and z positions for the elements distributed in 2D.