Development of large volume, high resolution tracking detectors based on capillaries filled with liquid scintillator

(eng) Searches for the decay of short-lived particles require real time, high-resolution tracking in active targets, which in the case of neutrino physics should be of large volume. The possibility of achieving this by using glass capillaries filled with organic liquid scintillator is being investigated in the framework of the CHORUS experiment at CERN. In this paper, after outlining the application foreseen, advances in the tracking technique are discussed and results from tests are reported. An active target of dimensions 180 × 2 × 2 cm3 has been assembled from capillaries with 20 μm diameter pores. The readout scheme currently in operation allows the reading of ∼ 5 × 105 channels using a single chain of image intensifiers having a resolution of σ ∼ 20 μm. Following the development of new liquid scintillators and purification methods an attenuation length of ∼3 m has been obtained. This translates into a hit density of 3.5 per mm for a minimum-ionizing particle that crosses the active target at a distance of 1 m from the readout end.