(space3d)¶

The @RadiationOutput module stores the 3D position of any electron emitting radiation directly at the detector, effectively creating a three-dimensional map of the origin of the radiation.

Directed radiation, such as bremsstrahlung and synchrotron radiation from relativistic electrons, can only be observed when the emitting electron is moving towards the detector. This is expressed in the equation

\[\hat{\boldsymbol{b}}(\boldsymbol{x}) \cdot \frac{\boldsymbol{x} - \boldsymbol{X}}{\left| \boldsymbol{x}-\boldsymbol{X} \right|} = \cos\theta_{\rm p},\]

where \(\hat{\boldsymbol{b}}\) denotes the magnetic field unit vector, \(\boldsymbol{x}\) is the position of the particle, \(\boldsymbol{X}\) is the detector’s position and \(\theta_{\rm p}\) denotes the particle’s pitch angle at \(\boldsymbol{x}\). The solution to this equation is the so-called surface-of-visibility, which can be studied using the Space3D module.

Summary of options¶

Option	Description
`@RadiationOutput(space3d) common`	List of common quantities to include in the output file.
`@RadiationOutput(space3d) output`	Name of output file to generate.
`@RadiationOutput(space3d) pixels`	Number of pixels in each dimension.
`@RadiationOutput(space3d) point0`	First edge point of pixel box.
`@RadiationOutput(space3d) point1`	Second edge point of pixel box.

Specification of pixel box¶

The Space3D output module creates a 3D histogram of where radiation that reached the detector was emitted from. The histogram is generated in a subset of space that is defined by the pixel box, illustrated below.

This box is defined by its two edge points, point0 and point1, indicated as red dots in the figure above, which specify its width, height and depth. The number of cells, or “pixels”, in the box is the same in each direction, and each cell records the radiation emitted from its region of space.

Note

One can think of the coordinates of each point as the “minimum” and “maximum” points respectively of the region to record. Thus, it is a good idea to always have point0 be element-wise smaller (or larger) than point1, i.e.

\[P^{(0)}_i < P^{(1)}_i, \quad i = x,y,z\]

Example configuration¶

The following example configures a Space3D output module to generate a surface-of-visibility consisting of \(100^3\) cells:

@RadiationOutput ourSpace3D (space3d) {
    output = "ourSpace3D.h5";
    pixels = 100;
    #         X      Y      Z
    point0 =  0.92, -1.06, -0.68;
    point1 =  2.21,  0.60,  0.48;
}

Output file structure¶

The output file contains the following variables:

Variable	Description
`image`	Pixel box/resulting image/histogram.
`pixels`	Number of pixels per dimension.
`xmin`	The x-component of `point0`.
`xmax`	The x-component of `point1`.
`ymin`	The y-component of `point0`.
`ymax`	The y-component of `point1`.
`zmin`	The z-component of `point0`.
`zmax`	The z-component of `point1`.

Common quantities¶

By default, no common quantities are included with output generated by this module. To add common quantities, use the @RadiationOutput(space3d) common option.

All options¶

common¶

Default value:	`none`
Allowed values:	See the list on @RadiationOutput.

Specifies which “common quantities” to include in the output file. A full list of possible options is given on @RadiationOutput.

output¶

Default value:	Nothing
Allowed values:	Any valid file name.

Specifies the name of the output file to generate. The file name extension determines the type of the generated file.

pixels¶

Default value:	Nothing
Allowed values:	Any positive integer.

The number of pixels per dimension in the pixel box.

point0¶

point1¶

Default value:	Nothing
Allowed values:	Any vector in 3D space.

Coordinates of the two edge points defining the pixel box. By convention, we usually assign the lower limits of each coordinate to point0 and upper limits to point1.