The CLAS drift chamber system

Abstract

Experimental Hall B at Je!erson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic "eld of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a "xed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and e$ciency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

Cascade production in the reactionsγp→K+K+(X)andGuo1, Weygand2, Kubarovsky3 et al. 2007Phys. Rev. C

“…The target consists of a 40-cm-long cylindrical cell containing liquid hydrogen. Momentum information for charged particles was obtained via tracking through three regions of multiwire drift chambers [17] inside a toroidal magnetic field (∼0.5 T), generated by six superconducting coils. Time-of-flight (TOF) scintillators were used for charged hadron identification [18].…”

Polarisation observables for strangeness photoproduction on a frozen spin target with CLAS at Jefferson Lab

“…The sense wires are 20 µm in diameter, and made of Gold-plated Tungsten, this small diameter limits wire tensions and operating voltages, while the choice of material has been made to ensure durability and chemical inertness [65]. The field wires are made of a Gold-plated Aluminium alloy and have a diameter of 140 µm.…”

A Search for an Exotic Meson in the Gamma P to Delta-plus-plus Pi-minus Eta Reaction

“…The CLAS drift chambers are arranged into six wedge-shaped sectors in a hexagonal configuration around the beamline [21] as shown in Fig. 2.7.…”

“…The second stage is the "timebased" tracking. By taking the time of flight, from the TOF and ST detectors, the initial wire times are converted to DIST using the calibrated drift velocity parameters [21].…”