Direction Apodization - Sampled as a function of spherical angles

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Sampled as a Function of Spherical Angles

Page Contents

Description

•Replace with data from file

•Digitizing apodization data

Related Topics

Description

The Sampled as a Function of Spherical Angles direction apodization type scales all source rays to an arbitrary intensity pattern defined in spherical coordinates. Apodization factors are entered as a function of azimuth and polar angles and values are linearly interpolated between these data points. If data is entered for only one Azimuth angle, then the apodization profile is considered rotationally symmetric. The following images show the source and intensity distribution for an isotropic plane of random rays emitting into a 90^ocone half angle with the Sampled as a Function of Spherical Angles apodization applied.

Navigation

The Sampled as a function of spherical angles directional apodization is available on the Power tab of a Detailed Source dialog. From the Power tab, select "Sampled as a function of spherical angles" from the drop down menu of directional apodization types.

Controls

The following table describes the available controls on the Power tab of a Detailed Source dialog. Of interest to this help topic are the Direction Apodization parameter settings.

Control	Inputs / Description	Defaults
Total Power	Total power of the source after both the position and direction apodization functions have been applied to the rays.	1
Position Apodization
Type	Drop down menu of available position apodization options.	Uniform
Parameters	Dependent on selected Type.
Direction Apodization
Type	Drop down menu of available direction apodization options. Select "Sampled as a Function of Spherical Angles" from the drop down menu.	Uniform
Parameters
Polar X, Y, Z	Direction vector of the polar axis in the apodization table. This vector is in the local coordinate system of the source node.	0, 0, 1
Azimuth X, Y, Z	Direction vector of the azimuth angle in the apodization table. This vector is in the local coordinate system of the source node.	1, 0, 0
Polar Angles(deg) – down Azimuth angles(deg) - across	The apodization table is organized such that column headers indicate Azimuth angles and row headers indicate Polar angles. The scale factors are then entered for each Polar-Azimuth angle pair.	0

OK	Accept settings and close the dialog box.
Cancel	Discard settings and close the dialog box.
Apply	Apply settings and keep the dialog box open.
Help	Access this Help page.

Application Notes

Adding angle data

Rows and columns can be added/inserted/deleted by right mouse clicking in the spreadsheet area and selecting either "Append Polar Angle", "Append Azimuthal Angle", "Insert Polar Angle", "Insert Azimuthal Angle", "Delete Polar Angle", or "Delete Azimuthal Angle". The azimuth angles must lie in the range of –180^oto 180^o and the polar angles must be in the range of 0^o to 180^o. If polar angle data for only one azimuth angle (column) is entered, then the apodization is assumed to be rotationally symmetric. If polar data is entered for more than one azimuth angle, then apodization factors for angles in between the entered data is linearly interpolated.

Replace with data from file

Apodization data can be read from a properly formatted text file using the "Replace With Data From a File" option, accessible by right mouse clicking in the spreadsheet area. The text file contains two header lines, two vectors (polar and azimuthal direction vectors) and then the data. The first header line must read "type direction_apodization", the second header line must read "format xyz_xyz_a", the third line contains the X, Y and Z components of the polar vector, the fourth line contains the X, Y and Z components of the azimuthal vector, the fifth line is a "0" followed by each of the sampled azimuthal angles (the zero is ignored), and the remaining lines are the polar angles and apodization factors in the form "angle val val val .....". The apodization values must be <= 1. An example file format is shown below with four azimuthal angles (-90^o, 0^o, 90^o, 180^o) and eighteen polar angles (0-85deg in 5^o steps).

Digitizing apodization data

Apodization data can also be digitized from a bitmap or other graphic file types.