Large Multiwire Proportional Chambers Research Articles

Improving MWPC delay line readout by waveform analysis

A readout method based on fast waveform digitalization is proposed which improves the performance of large multiwire proportional chambers (MWPCs) with delay-line readout. Atmospheric muon detection data are presented, obtained with a 1 mtimes1 m, 200 wire, MWPC and two plastic scintillators, having the same sensitive area, used for muon identification purposes. The performance of two alternative data acquisition configurations is compared: the standard one, based on analog constant fraction discriminators (CFDs), and one using 5 GS/s waveform digitizers in which a CFD-like analysis is performed offline. The latter is shown to provide better, and more uniform, space resolution, allowing to correct position-dependent rise-time variations across the detector. The new technique is applicable to low count-rate applications, such as muon attenuation measurements in large matter volumes

An X–Y encoder with fast centroid calculation for large multiwire proportional chambers

The system described here is part of a data acquisition system for macromolecular crystallography using a two-dimensional wire chamber with a spherical drift space. The readout consists of 2×128 cathode strips (4 mm width) which are connected to shaping amplifiers coupled to a fast high precision position encoder. Cathode amplitudes are converted digitally with flash analog-to-digital converters and valid cathode clusters give between 3 to 5 digital amplitudes. A specialized VME module calculates the center of gravity of the cluster. The entire system is constructed as a VME structure and is under program control from a VALET-plus VME microcomputer system (developed at the CERN) which allows fine tuning of the electronic system. Data acquisition rate is presently 200 kHz with less than 20% data loss. The useful sensitive area of the detector is a disk (diameter 486 mm). Local positional resolution is around 150 μm root-mean-square and long range positional reproducibility is better than 200 μm.

A system of large multiwire proportional chambers for a high intensity experiment

We describe a system of three multiwire proportional chambers used in the experiment NA24 at CERN. Each chamber consists of four wire places (2×2 m2 sensitive area), packed together in the same mechanical frame with only five cathode foils. All planes are electrically independent and can be operated individually although each of the three inner cathode foils is used for two adjacent wire planes. Another feature of the chamber is that an area around the beam can be desensitized to allow operation in a high intensity beam.

A system of large multiwire proportional chambers for a high intensity experiment

We describe a system of three multiwire proportional chambers used in the experiment NA24 at CERN. Each chamber consists of four wire planes (2 × 2 m 2 sensitive area), packed together in the same mechanical frame with only five cathode foils. All planes are electrically independent and can be operated individually although each of the three inner cathode foils is used for two adjacent wire planes. Another feature of the chamber is that an area around the beam can be desensitized to allow operation in a high intensity beam.

Development of large planar proportional chambers

We describe a set of large multiwire proportional chambers used in an experiment at the CERN Super Proton Synchrotron. The sensitive area is 2320 × 2320 mm 2, and four detecting planes, each with different orientation, are grouped together within the same mechanical frame. The number of wires for each module is 5000. Very uniform efficiency over the whole area is achieved by means of a simple mechanical construction. The chambers were operated for a long time without any damage under high particle flux.

Large multiwire proportional chambers for experiment NA3 at the CERN SPS

A description is given of large multiwire proportional chambers (sensitive area of about 8 m 2) designed and built for the experiment NA3 at CERN. The novel features of these chambers, like the use of graphite-coated cathode planes, spacers with compensating field wires and fast electronics are discussed. Details of the fabrication procedure and performance in the test beam and during experiments are also given.

Large multiwire proportional chambers for experiment NA3 at the CERN SPS

A description is given of large multiwire proportional chambers (sensitive area of about 8 m 2) designed and built for the experiment NA3 at CERN. Novel features of these chambers are discussed like, for example, the use of graphite coated cathode planes, spacers with compensating field wires and fast electronics. Details of the fabrication procedure and the performance in the test beam and during experiments are also given.

A high-resolution pair spectrometer for medium energy photons

The construction, performance and associated on- and off-line analysis procedures of a pair spectrometer for medium energy photons (50–150 MeV) is described. In a large aperture window frame magnet electrons and positrons from photons converting in thin gold foils are bent by 180°. The trajectories are observed with large multiwire proportional chambers. The performance of the system was tested with stopped π − and a liquid hydrogen target. The resolution is 840 keV (fwhm) at 129.4 MeV; the overall acceptance which includes solid angle probability, conversion efficiency, e +e − pattern recognition efficiency and trigger detector efficiency, is 2.5 × 10 −5 (or 1.030 MeV and 4.5 × 10 −5 respectively). With special care, the position of a photon line in the vicinity of the H line can be determined to an accuracy of a few keV, while the known absolute energy of the 129.4 MeV H line has been determined to an accuracy of about 0.1 MeV.

A system of proportional chambers for use in a photon beam experiment

The design, construction and performance, under test conditions, of a large multiwire proportional chamber system are described. The system consists of seven chambers, six 560 x 1298 mm 2 and one 1026 x 1794 mm 2, each containing three signal planes with a common high voltage plane between each adjacent pair. The plane spacing in all the chambers was 6 mm and the signal wire spacing 2 mm. The chambers have operated successfully, with their associated hybrid electronics, in a low intensity electron beam and all signal planes gave average efficiencies of ≈96% over their whole area using a magic gas mixture with a strobe width of 60 ns.

Tension control device for wires in large multiwire proportional chambers

A detailed description is reported on wire tension method and wire tension control for the large multiwire proportional chambers (2.6×1.3 m 2) used at the SPEAR I e +e − storage ring.

A New Monolothic Integrated Circuit for Multiwire Proportional Chamber (MWPC) Read-Out System

A new monolithic 8-channel PMOS integrated circuit has been developed for an experiment to be carried out on the CERN 300 GeV accelerator. The circuit, read-out electronics and tests performed on 12 large MWPC (total of 48 000 channels) are described and the results are presented.

The use of a new PMOS monolithic integrated circuit for the electronic equipment of large multiwire proportional chamber (MWPC) detection system

A new monolithic 8-channel PMOS integrated circuit has been developed for an experiment to be carried out on the CERN 300 GeV accelerator. The circuit, read-out electronics and tests performed on 12 large MWPCs (total of 48 000 channels) are described and the results are presented.

A system of multiwire proportional chambers for a large aperture spectrometer

Five large multiwire proportional chambers, ranging in size from 1.3 × 0.8 m 2 to 2.6 × 1.3 m 2, were built for magnetic spectrometer in use at the Stanford SPEAR I e + e − storage ring. We discuss the design and construction problems raised by the large size of the chambers, and described the solutions that were adopted. Results of efficiency and uniformity tests are also given.

Some features of large multiwire proportional chambers

Abstract This article describes multiwire proportional chambers of about 150 cm × 40 cm designed to operate in a large magnet at the CERN Intersecting Storage Rings. Five chambers with three different orientations of the sensitive wires were built in a modular construction. Measurements on efficiency, noise, and time- and space-resolution are reported.

Construction and performance of large multiwire proportional chambers

Large-area multiwire proportional chambers have been developed. In particular, a chamber 2 m × 0.5 m, using both horizontal and vertical wires (≈ 1500 wires in all), has been constructed. The chamber performance is very nearly the same as that of smaller chambers. Detailed design and performance data are presented.