Roman Pot Alignment
This page describes the SW tools contributing to the alignment of the TOTEM Roman Pots. The key modules are
- data formats (
TotemAlignment/RPDataFormats
),
- track-based alignment (
TotemAlignment/RPTrackBased
) and
- profile alignment (
TotemAlignment/RPProfiles
)
Track-based alignment
RPStraightTrackAligner
... to be written
Alignment file format (XML)
The file consists of a list of tags, each tag describes an alignment correction of an element, according to this table:
The alignment corrections are additive, that is the full correction for a Si sensor is obtained by combining the corrections from the
det
and the corresponding
rp
tag.
An element identified by its
id
attribute, which gives the decimal ID. The alignment correction is described by the attributes summarized in the following table:
attribute |
meaning |
sh_r |
shift in the read-out direction (only for det tags) |
sh_x |
shift in x direction |
sh_y |
shift in y direction |
sh_z |
shift in z direction |
rot_z |
rotation about the z axis |
The z axis follows the beam, x points outside the LHC ring, y goes up. The shift parameters are given in
micrometers, the rotation ones in
miliradians. For every attribute, there is an associated one with
_e
suffix, giving the uncertainty of the parameter.
ModifySingularModes
This plugin can be used to change the values of the singular modes (i.e. those that cannot be determined by the track-based alignment):
- unit shift in x (
de_x
parameters)
- unit shift in y (
de_y
parameters)
- unit rotation about z (
de_rho
parameters)
The shift/rotation parameters are specified at two z positions (
z1
and
z2
) parameters.
An example config file can be found in
TotemAlignment/RPTrackBased/python/ModifySingularModes_example.py
.
The
input
and
output
parameters give the file names of input and output alignment XML files.
Profile alignment
... to be written
--
JanKaspar - 07-Sep-2010