The muon spectrometer is arranged in front of the ALICE detector and is composed, among others, of hadronic absorber and 10 plans of wire chambers grouped in 5 stations. The latter allow to reconstruct the muons trajectory, bent by electromagnetic field of a dipolar magnet. Because of possible distortions and movements undergone by the structures, an alignment measurement of these 10 trajectography chambers, in better than 50 µm in the tracks curvature direction, is absolutely necessary to reach an invariant mass resolution better than 1%.

The GMS (Geometry Monitoring System) will allow to measure this alignment. It is constituted of optical lines BCAM and PROX among whom the number and the position were determined by simulation.

To allow the validaion of these simulations, the geometrical reconstructions programs as well as to study the effects on the dispersal of the measurements due to a thermal gradient etc., the LPSC took in charge the study and the realization of a workbench representing the scale 1 half a chamber) of stations 6, 7, 8 of the spectrometer. Chambers are realized in aluminum profiles. They allow the binding, in 4 corners, of optical elements such as they will be fixed in the experiment ALICE. The central chamber bases on motorized tables which allow known values moves, which GMS has to find. The chamber 6 is equipped with a heating and breathtaking device allowing to study the thermal influence of the active zones of the detector on the resolution of the optical elements measurements.

Our department took in charge:

The workbench technical coordination and realization.

The heating and breathtaking device study and the realization.

The study, the choice and the programming (LabVIEW) of 3 motorized tables.

The workbench assembly and the complete cabling.

The campaign of measurements, in which the department participated actively took place from January till June, 2006.

Report: Mehdi Meziane Training report

Report : Results from the test bench of the GMS










Contact : Muraz Jean-François




SuperB - FTOF


Logo-SuperB   FTOF

  • Design and realization of a muon detection telescope


This document presents the technical characteristics of this telescope


Contact : Muraz Jean-François




Within the framework of a collaboration between the LPSC UCN group and the Paul Scherrer Institute, the SDI developped its experience in the cryogenics field to take in hand the thorny problem of the cryogenic liquid deuterium level probe design and realization, mechanically resisting at the product solidification.

The proposed solution is a capacitive probe constituted of two concentric tubes adjusted in a extremely precise way. This very reliable solution does not exist in the market.

These probes are electrically bound with a small electronic oscillator, the signal output which presents a proportional frequency  of the liquidlevel.

In ice tests showed that the liquid solidification into which is dipped the probe does not damage it and does not modify its characteristics.

Four probes were so realized in 2007.

UCN 1