Ageing effects in drift chambers

The HERMES Back Drift Chambers

The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and e ciencies, and...

Drift and Proportional Tracking Chambers

Slow Control for Micromegas and Drift Chambers

A new spectrometer is being built for the COMPASS particle physics experiment at CERN. Saclay is in charge of the construction and the operation of two types of gaseous detectors: Micromegas microstrip detectors and Drift chambers [1], [2]. The operation of the detectors requires the slow control of high voltages and currents, and of the thresholds for the Front-End. This control system has bee...

The Drift Chambers Of The Nomad Experiment

We present a detailed description of the drift chambers used as an active target and a tracking device in the NOMAD experiment at CERN. The main characteristics of these chambers are a large area (3 × 3 m), a self supporting structure made of light composite materials and a low cost. A spatial resolution of 150 μm has been achieved with a single hit efficiency of 97% . 1 on leave from the Labor...

Ultraviolet Laser Calibration of Drift Chambers

We demonstrate the use of a focused ultraviolet laser as a track calibration source in drift chambers, and specifically in a small time projection chamber (TPC). Drift chambers such as TPCs reconstruct the trajectories of charged particles by amplifying and collecting electrons produced by ionization of gas atoms with which the target particle collides. The ultraviolet laser induces a two-photo...