High Resolution Tracking Devices Based on Capillaries Filled with Liquid Scintillator

%RD46 %title\\ \\The aim of the project is to develop high resolution tracking devices based on thin glass capillary arrays filled with liquid scintillator. This technique provides high hit densities and a position resolution better than 20 $\mu$m. Further, their radiation hardness makes them superior to other types of tracking devices with comparable performance. Therefore, the technique is attractive for inner tracking in collider experiments, microvertex devices, or active targets for short-lived particle detection. High integration levels in the read-out based on the use of multi-pixel photon detectors and the possibility of optical multiplexing allow to reduce considerably the number of output channels, and, thus, the cost for the detector.\\ \\New optoelectronic devices have been developed and tested: the megapixel Electron Bombarded CCD (EBCCD), a high resolution image-detector having an outstanding capability of single photo-electron detection; the Vacuum Image Pipeline (VIP), a high-speed gateable pipeline with 1 $\mu$s delay, allowing operation in high-rate environments. A large size capillary detector with a readout based on the newly developed EBCCD, was installed and put in operation in front of the CHORUS detector. A neutrino interaction event taken with this prototype is shown in Figure 1.\\ \\During 1997 and 1998 the technique of thin planar capillary layers was developed with the aim of adapting capillary detectors to future HEP experiments. Procedures of capillary assembling, cutting and filling have been studied. Two cosmic ray events recorded in a detector prototype built in summer 1998 are shown in Figure 2.\\ \\During 1999 a new study has been undertaken in collaboration with other teams interested in neutrino physics. The aim of the R\&D is the use of EBCCDs in high performance, low cost per channel, multipixel readout systems for large tracking detectors based on scintillators and w.l.s. fibres

Observation of neutrino induced diffractive Ds*+ production and subsequent decay Ds*+ › Ds+ › ?+ › µ+

We report on the first direct observation of a neutrino induced charged-current interaction with two subsequent decays of short-lived particles close to the interaction vertex. This rare double-kink signature in the CHORUS emulsion target is interpreted as a Ds*+ production followed by the decay chain Ds*+ › Ds+ ?, Ds+ › ?+ v?, ?+ › µ+ vµ v?¯. The event is characterised by small Q2 and small four-momentum transfer squared t to the target nucleon, which indicates a diffractive production mechanism. A complete analysis of the event is presented. © 1998 Elsevier Science B.V. All rights reserved.Japan Society for the Promotion of Science Bundesministerium für Bildung und Forschung: 057MS12P CERN Brussels Instituut voor Milieubeheer Israel Science Foundation: 328/94 Korea Science and Engineering Foundation: BSRI-97-2407 Instituto Nazionale di Fisica Nucleare Foundation for Fundamental Research on MatterOne of us (O.M.) would like to thank P. Marage, L. Sehgal and D. Rein for useful discussions on diffractive production. We gratefully acknowledge the support of all our technical collaborators contributing to the detector construction, operation, emulsion pouring, development and scanning. We thank the neutrino beam staff ensuring the excellent performance of the facility. The accumulation of a large data sample in this experiment has been made possible also thanks to the efforts of the crew operating the CERN PS and SPS. The general technical support from the CERN EP and IT divisions is gratefully acknowledged. The experiment has been made possible by grants from the following funding agencies: the Institut Interuniversitaire des Sciences Nucléaires and the Interuniversitair Instituut voor Kernwetenschappen (Belgium), the Israel Science foundation (grant 328/94) and the Technion Vice President Fund for the Promotion of Research (Israel), CERN (Geneva, Switzerland), the German Bundesministerium für Bildung und Forschung (grant 057MS12P(0)) (Germany), the Institute of Theoretical and Experimental Physics (Moscow, Russia), the Istituto Nazionale di Fisica Nucleare (Italy), the Japan Private School Promotion Foundation and Japan Society for the Promotion of Science (Japan), the Korea Science and Engineering Foundation and the Ministry of Education through Research Fund (BSRI-97-2407)(Republic of Korea), the Foundation for Fundamental Research on Matter FOM and the National Scientific Research Organization NWO (The Netherlands), and the Scientific and Technical Research Council of Turkey (Turkey)

Observation of neutrino induced diffractive D-s*(+) production and subsequent decay D-s*(+)-> D-s(+)->tau(+)->mu(+)

WOS: 000076278900032We report on the first direct observation of a neutrino induced charged-current interaction with two subsequent decays of short-lived particles close to the interaction vertex. This rare double-kink signature in the CHORUS emulsion target is interpreted as a D-s*(+) production followed by the decay chain D-s*(+) --> D-s(+) gamma, D-s(+) --> tau(+) v(tau),tau(+) --> mu(+) v(mu)v(tau). The event is characterised by small Q(2) and small four-momentum transfer squared t to the target nucleon, which indicates a diffractive production mechanism. A complete analysis of the event is presented. (C) 1998 Elsevier Science B.V. All rights reserved

A new vertex detector made of glass capillaries

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 × 105 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.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The data acquisition system of the CHORUS experiment

In the years 1994-1998 the CHORUS Collaboration has recorded data in the CERN WA95 experiment. Here we describe the data acquisition system that has been used, featuring concurrent hierarchical state machines, a remote operating system, a buffer manager, a dispatcher, a control panel and a supervisor. (C) 2002 Elsevier Science B.V. All rights reserved

Capillary detectors for high resolution tracking

We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 x 10(5) capillaries with a diameter of 20 mu m and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 mu m was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented

Tracking with capillaries and liquid scintillator

The technique of glass capillaries filled with liquid scintillator allows the reconstruction of ionizing particle tracks with high spatial resolution. Detectors based on this technique consist of coherent arrays of capillaries having diameters of the order of 20 mu m. Light signals are amplified by an optoelectronic chain composed of a series of image intensifiers: the readout is performed through a CCD. The ongoing research in the field of liquid scintillators has led to excellent results in terms of information density (greater than or equal to 5 hits/mm) and radiation resistance (order of 1 MGy). In this paper new results about the effect of ageing and purification of liquid scintillators will be presented. The RD46 collaboration has developed a completely new detector having a readout chain composed of only one image intensifier followed by a new device: a Megapixel Electron Bombarded CCD. First images of neutrino interactions will be shown, together with preliminary measurements of the resolution of the detector

Observation of weak neutral current neutrino production of J/ψJ/\psi

Observation of \jpsi production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band \numu beam is reported. A spectrum-averaged cross-section $\sigma^{\mathrm{J/\psi}}$ = (6.3 $\pm$ 3.0) $\times \mathrm{10^{-41}~cm^{2}}$ is obtained for 20 GeV $\leq E_{\nu} \leq$ 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism