DEVELOPMENT OF LARGE-VOLUME, HIGH-RESOLUTION TRACKING DETECTORS BASEDON CAPILLARIES FILLED WITH LIQUID SCINTILLATOR

Searches for the decay of short-lived particles require real time, hig h-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 t he tracking technique are discussed and results from tests are reporte d. An active target of dimensions 180 X 2 X 2 cm(3) has been assembled from capillaries with 20 mu m diameter pores. The readout scheme curr ently in operation allows the reading of similar to 5 x 10(5) channels using a single chain of image intensifiers having a resolution of sig ma similar to 20 mu m Following the development of new liquid scintill ators and purification methods an attenuation length of similar to 3 m has been obtained. This translates into a hit density of 3.5 per mm f or a minimum-ionizing particle that crosses the active target at a dis tance of 1 m from the readout end.