Henry T. Wong

The CHORUS scintillating fiber tracker and opto-electronic readout system

Abstract A scintillating fiber tracker system consisting of more than one million fibers has been successfully constructed and made operational for the CERN WA95/CHORUS experiment. The design and construction of the tracker system as well as its opto-electronic readout are described. The performance of the detector with high-energy muons is presented.

High-resolution tracking using large capillary bundles filled with liquid scintillator

Abstract We have developed large high-resolution tracking detectors based on glass capillaries filled with organic liquid scintillator of high refractive index. These liquid-core scintillating optical fibres act simultaneously as detectors of charged particles and as image guides. Track images projected onto the readout end of a capillary bundle are visualized by an optoelectronic chain consisting of a set of image-intensifier tubes followed by a photosensitive CCD or by an EBCCD camera. Two prototype detectors, each composed of ≈10 6 capillaries with 20– 25 μm diameter and 0.9–1.8 m length, have been tested, and a spatial resolution of the order of 20– 40 μm has been attained. A high scintillation efficiency and a large light-attenuation length, in excess of 3 m, was achieved through special purification of the liquid scintillator. Along the tracks of minimum-ionizing particles, the hit densities obtained were ∼8 hits / mm at the readout window, and ∼3 hits / mm at ∼1 m away. The level of radiation resistance of the prototype detectors is at least an order of magnitude higher than that of other tracking devices of comparable performance.

Scintillating fiber trackers with optoelectronic readout for the CHORUS neutrino experiment

Abstract The CERN WA95/CHORUS collaboration has been constructing a hybrid detector to search for ( ν μ - ν τ )-oscillations. An essential component of the detector is a scintillating fiber tracking system for precise track reconstruction of particles. The physics motivation is explained, and the detector layout, the tracker design, its optoelectronic readout and test beam results are presented.

A new vertex detector made of glass capillaries

Abstract We have developed a new detector technique that allows high quality imaging of ionizing particle tracks with very high spatial and time resolution. Central to this technique are liquid-core fibres of about 20 μm diameter read out by an optoelectronic system including a CCD. The fibres act simultaneously as target, detector and light guides. A large-volume prototype, consisting of 5 × 10 5 capillaries of 20 μm diameter and 180 cm length, has been tested in the CERN wide-band neutrino beam. A sample of high-multiplicity neutrino interactions was recorded, demonstrating the imaging quality of this detector. First results from the reconstruction of these events are reported. A track residual of 28 μm and a vertex resolution of 30 μm has been achieved. Future applications of capillary detectors for neutrino and beauty physics are being investigated within the framework of the RD46 collaboration.

Charged-particle tracking with high spatial and temporal resolution using capillary arrays filled with liquid scintillator

We abstract developed a new technique that allows the trajectories of ionizing particles to be imaged with very high spatial and temporal resolution. This technique, developed for future experiments in high-energy physics, may also be applied in other field. Central to the technique is a detector consisting of a bundle of thin, glass capillaries filled with a liquid scintillator of high refractive index. These liquid-core scintillating fibers act simultaneously as a detector of charged particles and as an image guide. Track images seen at the readout end of the capillary bundle are amplified by an optoelectronic chain consisting of a set of image- intensifier tubes and read by a photosensitive CCD camera. We report here on results obtained with detector prototypes. A spatial resolution of 6-14 micrometers , dependent on image magnification prior to readout, has been obtained with 16 micrometers capillaries. The high scintillation efficiency of the liquid scintillator used and a large light attenuation length-- approximately 3 m for 20 micrometers capillaries--result in hit densities along the track of a minimum-ionizing particle of 8.5 mm-1 and 3.5 mm-1 at distances from the readout window of approximately 2 cm and approximately 1 m respectively. The radiation resistance of the detector is an order of magnitude greater than that of other types of tracking device of comparable performance. To complement the detector we have been developing a new readout system based around a gateable vacuum image pipeline (VIP) and an electron- bombarded CCD camera. These increase the spatial and temporal resolution obtained with detector and render it particlarly attractive as a microvertex detector for the observation of short-lived particles in high-energy physics experiments performed with evelated interaction rates.

CHORUS scintillating fiber tracker and optoelectronics readout system

An essential component of the CERN WA95/CHORUS experiment is a scintillating fiber tracker system made up of more than one million scintillating fibers, for the precise track reconstruction of particles. The design and construction of the tracker system as well as its opto-electronics readout are discussed. Performances of the detector are presented.

Scintillating fiber tracker system of the CHORUS experiment

The CERN WA95/CHORUS Collaboration has been constructing a detector to search for neutrino oscillations. An essential component of the detector is a scintillating fiber tracker system for precise track reconstruction of particles. An overview of the tracker system design, its opto-electronics readout, data processing and test beam measurements is presented.