Xraytrace documentation

VERBOSE
integer

- sets verbosity level. Below 3 this means not many messages and should be used for normal work. Above 3 this means a lot of details of every individual ray. Value of 10 means also debugging data for each ray and no intensity decay in output field data. Default value is 0.

RAYS
integer

- sets total number of rays to be casted. Value around 10000 should be fine for beams of radius around 10. Set to unity if you want to understand better what is happenning, ideally with increasing verbosity level and decreasing the beam radius. Default value is 1.

COMP
double double double double

- sets ray direction in theta, phi coordinates, in degrees, with similar orientation as used in GSvit. Ray should be incident to the center of computational domain. If there is a material at the boundary, it does not refract there, and goes directly inside. As third parameter, this command also sets the radius of the beam - rays are randomly shifted in this radius to produce an idealaly collimated beam. Finally, wavelength is supplied, in meters. Default value is 90 degrees theta, 0 degrees phi, 1 voxel radius, which corresponds to ray propagating in x direction (towards positive values). See image below for angles meaning (polarisation angle psi is not used so far):

SCAN_THETA
90.01 91.5 0.01

Do multiple calculation to scan across some theta range, with given step.

NORMALIZE
double int

- normalizes result by value obtained at given angle for given material.

MULTSTEP
double

- multiplies the raytracing step by a double. Default is 1, which means approximately a voxel size.

CENTER
0/1

- sets if the ray evaluation should be centered to cell in coherent calculations.

MAXDEPTH
integer

- sets maximum depth of secondary rays for multiple reflections - i.e. maximum number of rays produced from one incident ray. Default value is 10.

CUTMAT
integer

- sets the material to which rays should not enter from source. Default is -1 which means not doing it.

TERMINATE_LIMIT
double

- sets ray termination intensity limit, e.g. 1e-15 which is default value. Incident intensity of a ray is 1 and if the intensity fails below this criterium it is not propagated further.

REGIME
integer

- sets regime of calculation. 0 means illumination only - ray illuminates first material that is not zero and dies. 1 means rays illuminating volume, passing through without any optical effects. 2 means geometrical optics, 3 means only reflections like from perfect metal at any material interface Default value is 2.

MAXSTEP
integer

- set maximum number of steps for every individual ray computation. Normally, the ray progresses by one voxel in each step, so this value should not be smaller than size of the computational domain. If it is not enough, software issues a warning. Default value is 100000.

PERIODIC_XY
xstart ystart xend yend optimize

Creates periodic BC. If optimization is requested, end boundary is shifted towards making it periodic with respect of incident signal wavelength and angles.