13th Vienna Conference on Instrumentation - VCI2013

Performance of Drift Tube Detectors at Very High Counting Rates at High-Luminosity LHC

Not scheduled

50m

Vienna University of Technology

Board: 29

Poster Gaseous Detectors

Speaker

Dr Hubert Kroha (Max-Planck-Institut fuer Physik)

Description

The performance of pressurized drift-tube chambers at very high background counting rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications as large-area precision muon tracking detectors at high-luminosity upgrades of the Large Hadron Collider (LHC). The present ATLAS muon drift-tube (MDT) chambers with 30mm tube diameter are designed to cope with gamma and neutron background rates of up to 500 Hz per square cm or 300 kHz per tube. Background rates of up to 14 kHz per square cm and 1150 kHz per tube are expected at LHC upgrades. The test results for gamma irradiation rates of up to 1400 kHz per tube and 8.5 kHz per square cm and for proton rates up to 2800 kHz per tube and 1330~kHz per square cm show that by reducing the drift-tube diameter to 15 mm while leaving the other operating parameters unchanged, the rate capability is vastly increased. With the 3.8 times shorter maximum drift time of 185 ns the drift-tube occupancy per unit length is reduced by a factor of 7.6. The degradation rate of the drift-tube spatial resolution due to space charge effects is reduced by more than an order of magnitude. The shorter maximum drift time allows also for a reduction of the adjustable deadtime of the MDT readout electronics from 790 ns to the minimum of 175 ns leading to a decisive improvement of the muon hit reconstruction efficiency.

Presentation materials

Slides

VCI2013_poster.pdf