MAKETHIN

EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

MAKETHIN: Slice a sequence into thin lenses

This module converts a sequence with thick elements into one composed entirely of thin elemtens as required by the default MAD-X tracking.

Slicing is done by the MAKETHIN command:

MAKETHIN,SEQUENCE=sequence name,
         STYLE=slicing style;

The parameters are defined as:

SEQUENCE chooses the sequence you wish to slice.
STYLE (optional) chooses the slicing style. The options are:
- SIMPLE : this is a simplified slicing algorithm which produces any number of equal strength slices at equidistant positions with the kick in the middle of each slice.
- COLLIM : this is the default slicing for collimators. If only one slice is chosen it is placed in the middle of the old element. If two slices are chosen they are placed at either end. Three slices or more are treated as one slice.
- [TEAPOT] (default): this is the standard slicing as used by MAD9. N.B. This has a maximum of four slices for any one object.

By default all elements are converted to one thin element positioned at the center of the thick element. To get a greater slicing for certain elements use a standard SELECT command with FLAG=MAKETHIN and CLASS, RANGE or PATTERN:

SELECT,FLAG=MAKETHIN,
       CLASS=class,RANGE=range,
       SLICE=no of slices;

The created thin lens sequence has the following properties:

The created sequence has the same name as the original. The original is therefore no longer available and has to be reloaded if it is needed again.
The slicer also slices any inserted sequence used in the main sequence. These are also given the same names as the originals.
Any component changed into a single thin lens has the same name as the original.
If a component is sliced into more than one slice, the individual slices have the same name as the original component and a suffix ..1, ..2, etc... and a marker will be placed at the center with the original name of the component.

Hints:

See the examples for makethin.
Compare the optics before and after slicing with makethin. Consider to increase the number of slices and rematch after makethin to reach the required accuracy.
Consider to replace rbend by sbend + thin quads taking into account the edge focusing before slicing with makethin.
The selection works on the current sequence. Consider to insert a "USE,SEQUENCE=.." before SELECT

Helmut Burkhardt, September 2005