LHCRealOpticsTools

The Roman Pot stations are dedicated tools to detect particles which follow the beam pipe with a tiny deviation after the collision. These particles are affected by the magnetic fields which are distributed along the beam pipe. Hence the TOTEM experiment is particularly interested in the status of the magnetic fields between the interaction point IP5 and the Roman Pot stations to interpret the hit distributions. This obviously means that we would like to know the operating conditions of the magnets in this range as precisly as it is possible. Furthermore we want to derive as much information as we can from the raw information. The LHCRealOpticsTools was designed to

• collect raw information about the relevant LHC magnet sequence. It basically means retrieving the currents of the magnets and the strength of their magnetic field.
• extract additional information from the raw data, which means to calculate the so called optical or transport funtions to the given field.

Reader Utility

Reading the relevant magnets from LSA (LHC Software Architecture), the output is directly in MAD-X form. It can be saved to a text file, by simply redirecing the output. The result works together with the magnet and variable setting file.

• MagnetDefs.seq
• VariableDefs.seq

Including all these files to a given .madx file will change the magnet settings in the correct way.

Mappings and Settings

The Mappings directory should contains the lists and mappings, for example magnets names in s order.

• Map from magnet name to its power converter names.
• List of magnets in s order.

Perturbations Utility

This utility is doing the perturbations for a given optics. The following parameters are perturbed

• Magnet strengthes, positions, rotations (MQXA, MQXB, MQY, MQML, MQSX)
• Beam position and energy
• Harmonics and alignment

The shell script GeneratePerturbations.sh do the perturbations.

Matching Utility

This utility provide a MINUIT fit for the optical functions, where we use the constraints from reconstruction. The aim is to derive a reasonable value for Ly and dLx/ds while our measured constraints are given in Lx and dLy/ds to obtain. The matcing should start with

• root -l match.C

where match.C is the matching utility.

ParallelConstraints Utility

This code is designed for doing MonteCarlo runs for the optics. The LSA settings are perturbed and then a matching process is started from the nominal.

• SendParallelConstraints

ParallelMatching Utility

This is the matching of the optical constraints.

• SendParallelMatching

-- FrigyesNemes - 07-Nov-2011