The resolution and position of several variables can be optimized. To start an optimization give either the command
optimize/calibrate variable condition
The condition can be any valid logical statement. The variable combinations that can be optimized are:
Except for the optimization of , an additional input file has
to be supplied. Since the selection of events used in the optimization
procedure is usually too complicated to be accomplished through a series of cuts
defined in ESPACE, this file contains information for the event selection.
The file can be assigned through the comand
set/file/fit_input
,
see reference section.
For the different optimization options this file has a different format. First
we discuss the case that the vertex reconstruction of a spectrometer is
optimized, so dp_kin
, theta_tg/phi_tg
and y_tg
.
Then this file should contain in the first line the number of positions along
the focal plane where one wants to optimize, followed by a line for each
position containing the center of this region, its new position (only useful
when dp_kin
is being optimized) and the half width of this region.
If one wants to optimize theta_tg/phi_tg
or y_tg
additional
data has to be supplied. In case of theta_tg/phi_tg
this should be
the number of holes in the sieve collimator. It has to be followed by a
line for each hole giving the center of the hole in before
optimization,
hole position after optimization and half the
width of the ellips in the
direction which will be put around the
initial coordinates of the hole center. The same should be given for
phi_tg
. Only those events are used which have their initial values inside
one of the ellipses. The beginning of a FIT-FILE for optimizing
theta_tg/phi_tg
with a 77-hole sieve-collimator would look
like
77 (theta_ini, theta_final, dtheta, phi_ini, phi_final, dphi) -0.04500 -0.07024 0.0075 -0.08600 -0.09757 0.0050
The input for optimizing y_tg
would consist out of first a line with
the number of beam-spot positions which is being used in the optimization.
It is followed by a line for each beam-spot position with the initial
position, final position and half the width of the region around the initial
position containing the events that are accepted for the optimization.
An important parameter in the optimization procedure is the variable
that controls the number of events per peak per file that is being
used (command set/fit/npts
). With this variable one can prevent that the
data used in the fit is coming from just the first few files being scanned.
If e_miss
is optimized the file should contain in the first line the
number of peaks in the missing energy spectrum that one wants to optimize.
This is followed by a line for each peak containing the center of this region,
its new position and the half width of this region. All in units of MeV.