FTABLE

Tracks through a magnetic field which is expressed by a SDDS table.
Parallel capable? : yes

Parameter Name	Units	Type	Default	Description
L	$M$	double	0.0	The effective field length measured along a straight line.
ANGLE	$RAD$	double	0.0	The designed bending angle
L1	$M$	double	0.0	The left fringe field length.
L2	$M$	double	0.0	The right fringe field length. L1+L+L2=Total z span in the input field table.
E1	$RAD$	double	0.0	The designed entrance edge angle
E2	$RAD$	double	0.0	The designed exit edge angle
TILT	$RAD$	double	0.0	rotation about incoming longitudinal axis
DX	$M$	double	0.0	misalignment
DY	$M$	double	0.0	misalignment
DZ	$M$	double	0.0	misalignment
INPUT_FILE		STRING	NULL	Name of SDDS file which contains field data.
N_KICKS		long	1	Number of kicks into which to split the element.
VERBOSE		long	0	Used for debugging code. Not applicable to Pelegant
GROUP		string	NULL	Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup

This element is used for tracking through an arbitrary magnetic field when its values are known at regularly spaced grid points and it is hard to find a suitable model to describe it. The input magnet parameter and coordinate system definition are illustrated in Fig:1. The field data is saved in a 3 pages ($B_x$, $B_y$, $B_z$) 3D histogram SDDS table (see MHISTOGRAM for detail). An example is shown in Fig:2. This SDDS file must have one column Frequency to store the field data in Tesla, and following parameters:

• ND -- Type ``long''; Value ``3''.
• Variable00Name, Variable01Name,Variable02Name -- Type ``string''; Value ``x'', ``y'', ``z''.
• Variable00Min, Variable01Min, Variable02Min -- Type ``double''; Value: the minimum boundary coordinates of ``x'', ``y'', ``z'' in meter. Variable02Min (z_min) must start from zero.
• Variable00Max,Variable01Max, Variable02Max -- Type ``double''; Value: the maximum boundary coordinates of ``x'', ``y'', ``z'' in meter.
• Variable00Interval, Variable01Interval,Variable02Interval -- Type ``double''; Value of the grid size of ``x'', ``y'', ``z'' in meter.
• Variable00Dimension,Variable01Dimension, Variable02Dimension -- Type ``long''; Value of total number of grid points in ``x'', ``y'', ``z''. For example: Variable00Dimension =(Variable00Max-Variable00Min)/Variable00Interval + 1.

Figure 1: Illustration of coordinate system and magnet definition.

Figure 2: Example of SDDS input file. The column x_index, y_index, z_index is not the necessary part, it's shown here just for clarifying how the data is arranged