Nuclear Instruments and Methods in Physics Research最新文献

The Design of a silicon strip diode detector for use at LEP is described. It will use a custom-designed NMOS read-out chip, to reduce the size and cost of the associated electronics.

The characteristics of plastic optical fibres (scintillating or not) are of interest for particle detection. Scintillating fibres added fine grain sampling to the time resolution and amplitude level measurements of classical scintillators. They can be used for hodoscopes, calorimeters and time of flight. Wire chambers' time resolution could be improved by the use of shifter fibres. Light guides and signal transmission could be made with non-doped fibres.

The results of a feasibility study of such fibres at the Departement de Physique des Particules Elémentaires de Saclay will be presented.

A description is given of a new fine-grained single gap shower chamber with analog read-out of its three coordinates (wires, strips, pads), installed in the NA3 prompt photons experiment at CERN. Measurements of positional precision and preliminary physics results obtained by the experiment with this detector are presented.

Several improvements have recently been made to the TRIUMF TPC. These include the addition of a grid system, corrections to the electrostatic field cage and a sequential gate generator. Our experience with this new TPC will be discussed.

We report on the performance of a high pressure hydrogen filled time projection chamber (TPC) designed to study photon diffraction dissociation on hydrogen. The TPC consists of two identical 75 cm long by 45 cm diameter drift regions filled with H₂ at 15 atm. It is used as an active target to measure the polar angles and dE/dx of recoil protons.

The development of Saclay of scintillating fibers allows new compact structures for calorimetry. The construction of a prototype module designed and built at Saclay is described. It contains 3300 scintillating fibers regularly positioned and immersed in a low melting point BiPb alloy, giving a global radiation length of X₀ = 11.2 mm. Results of tests performed on an electron beam at DESY are presented and discussed. In addition, some ideas for industrial production are proposed.

We present a FADC solution as a digitiser for the DELPHI TPC. After a review of the prototype work, we outline a proposal for a final readout preprocessing and data acquisition.

In Europe, several massive modular tracking calorimeters are in operation (Mont Blanc), under construction (Fréjus), or in the planning stage (Gran-Sasso), to search for nucleon decay. Im view of the stringent limit on the partial lifetime τ(p → e⁺π⁰ recently obtained by the IMB water Cherenkov experiment in the USA, this choice is well justified, because the tracking calorimeters should be sensitive to decay modes other than the SU(5) favoured p → e⁺π⁰.

HOLMES is a working prototype of a scanning and measuring machine for in-line holograms of HOBC heavy liquid bubble chamber events.

Computer simulated drift chamber pulses are used to investigate various possible timing strategies in drift chambers. In particular, leading edge, multiple threshold and flash ADC timing methods are compared. Although the presented method is general for any drift geometry, we concentrate our discussion on jet chambers where the drift velocity is about 3–5 cm/μs and the individual ionization clusters are not resolved, due to a finite speed of our electronics. We will not discuss the geometries where the drift time is expanded further and the individual clusters can be recorded (this is covered by a talk by Walenta).