&DRIFT: XT-PLOT
Requests output of the x(t) relation to a dataset [no dataset is
written by default].
The dataset name. The name should be enclosed in single
quotes if it
contains any of the following: blank, comma, colon, double quote,
equal sign. This means in practice that the quotes are required on
a Vax for all dataset access outside the home disk. On VM/CMS, the
blanks between file-name and file-type (and perhaps file-mode) may
be replaced by dots, thus avoiding the need to add the quotes. On
Unix systems, the name should be surrounded by double quotes so as
to avoid case conversion of the file name.
An identification string of at most 8 characters. This string is used
by the various dataset commands and it is also needed if you keep
more than one object (member) of the same type (cell, gas, track etc)
in the same dataset.
A string of at most 29 characters that serves as a comment helping
you to recognise a member in a dataset. The default remark for x(t)
relations states the wire number and the angle.
The angle of the lines over which the drift time is minimised,
measured with respect to the y-axis. The accuracy of the calculations
becomes less when this angle becomes large.
[Default: 0 degrees.]
The range in x to be covered by the x(t) relation.
[By default the whole x-range of the drift area is taken.]
The distance between successive x points for which a corresponding
minimal drift time is computed.
[By default chosen such that the step size is a reasonable number
for about 20 data points.]
The number of points between two accurately calculated points. The
drift times for the intermediate points are obtained by interpolating
the minimising drift line from the adjacent points, a procedure that
is slightly less accurate than full drift line calculation.
[By default, no point is interpolated.]
The maximum number of iterations allowed.
[Default: 5.]
An accuracy parameter, to be adjusted with great care.
[Default: 1E-4.]
To save CPU time whilst gaining precision, it sometimes makes
sense to explore only a limited angular range as seen from the
target sense wire.
This option should be used with great caution if a magnetic
field is present since the drift lines in this case normally
approach the wire at a (substantial) angle.
[The default range is +90 to -90 degrees both left and right.]
Requests a printout of the x(t) relation.
[On by default.]
Requests a graph of the x(t) relation.
The graph usually shows 2 curves:
- a curve plotted with representation
FUNCTION-1
which shows the minimum drift time that has been found;
- a curve plotted with representation
FUNCTION-2
which shows the integrated diffusion for the fastest drift line.
Both curves are interrupted if the procedure has doubts about
the accuracy of a neighbouring point - markers are used if both
neighbours of a reliable point are considered unreliable.
[On by default.]
Can be used to force a vertical scale in the x(t) relation plot,
e.g. when you wish to overlay several of them.
Go to the top level,
to &DRIFT,
to XT-PLOT,
to the topic index
or to the table of contents.
Formatted on 0103-05-16 at 14:05.