source: PSPA/madxPSPA/doc/usrguide/makethin/makethin.html @ 430

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1<head>
2<title>MAKETHIN</title>
3<!-- Changed by: Helmut Burkhardt,  7-April-2005 -->
4</head>
5
6<body bgcolor="#ffffff">
7<center>
8EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
9<IMG SRC="http://cern.ch/madx/icons/mx7_25.gif" align=right>
10
11<h2>MAKETHIN: Slice a sequence into thin lenses</h2>
12</center>
13This module converts a sequence with thick elements into one composed entirely of
14thin elemtens as required by the default MAD-X tracking.
15</P>
16Slicing is done by the MAKETHIN command:
17<pre>
18MAKETHIN,SEQUENCE=sequence name,
19         STYLE=slicing style;
20</pre>
21The parameters are defined as:
22<ul>
23<li>SEQUENCE chooses the sequence you wish to slice.
24<li>STYLE (optional) chooses the slicing style. The options are:
25  <UL>
26    <LI>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.
27    <LI>COLLIM : this is the default slicing for collimators. If only one slice is
28chosen it is placed in the middle of the old element. If two slices are chosen they
29are placed at either end. Three slices or more are treated as one slice.
30    <LI>TEAPOT : this is the slicing algorithm described in <a href="../Introduction/bibliography.html#TEAPOT">[TEAPOT]</a> but generalized to any number of slices.
31    <LI>
32    (default): this is the standard default slicing for all elements (except collimators). It uses TEAPOT if the number of slices &le; 4, and SIMPLE otherwise.
33  </UL>
34</ul>
35
36<span style="font-weight: bold;">By default</span> all elements are converted to one thin element positioned at the center of  the thick element.
37To get a greater slicing for certain elements use a standard SELECT command with FLAG=MAKETHIN and
38CLASS, RANGE or PATTERN:
39<pre>
40SELECT,FLAG=MAKETHIN,
41       CLASS=class,RANGE=range,
42       SLICE=no of slices;
43</pre>
44
45The created thin lens sequence has the following properties:
46<ul>
47<li>The created sequence has the same name as the original. The original is therefore no longer
48available and has to be reloaded if it is needed again.
49<li>The slicer also slices any inserted
50sequence used in the main sequence. These are also given the same names as the originals.
51<li>Any component changed into a single thin lens has the same name as the original.
52<li>If a component is sliced into more than one slice, the individual slices have the same
53name as the original component and a suffix <tt>..1</tt>, <tt>..2</tt>, etc... and a marker
54will be placed at the center with the original name of the component.
55</ul>
56
57Hints:
58<ul>
59<li>See the <a href="http://cern.ch/frs/mad-X_examples/makethin/">examples</a> for makethin.
60<li>Compare the optics before and after slicing with makethin. Consider to increase the number of slices and rematch
61after makethin to <span style="font-weight: bold;">reach the required accuracy</span>.
62<li>Consider to replace rbend by sbend + thin quads taking into account the edge focusing before slicing with makethin.
63<li>The selection works on the current sequence. Consider to insert a "USE,SEQUENCE=.." before SELECT
64</ul>
65
66<HR>
67<address>
68Helmut Burkhardt, September 2005
69</address>
70
71</body>
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