A two-step parallel plate chamber with a resistive germanium anode and a two dimensional readout for the detection of minimum ionizing particles

Abstract A parallel plate avalanche chamber specially suited for the high resolution detection of minimum ionizing particles (m.i.p.) is presented. The anode is made of a thin germanium layer with a sheet resistivity > 1 M Ω/p[ while the cathode is made of a nickel mesh having 600 line pairs/in. A chess board of pads placed behind the anode plane is used to obtain the positional information. A 100% detection efficiency, a 40 ns (fwhm) time resolution and a spatial resolution better than 140 μm (fwhm) for both coordinates have been measured

A novel type of parallel plate chamber with resistive germanium anode and a two-dimensional readout

Abstract A parallel plate counter with a resistive anode and a two-dimensional readout is presented. The anode is made of a thin germanium layer with a sheet resistivity ⩾ 1 M ω /square and the cathode is made of aluminized mylar 5 μm thick. The anode is transparent to the fast impulse due to the collection of the multiplication electrons. A chessboard of "pads" placed behind the anode plane is used to obtain the positional information. The detector and the readout system are physically and logically separated. An overall spatial resolution of 70 μm (rms) for both coordinates has been measured

A microstrip gas avalanche chamber with two-dimensional readout

Abstract A microstrip gas avalanche chamber with a 200 μm anode pitch has been built and successfully tested in our laboratory. A gas gain of 104 and an energy resolution of 18% (FWHM) at 6 keV have been measured using a gas mixture of argon-CO2 at atmospheric pressure. A preliminary measurement of the positional sensitivity indicates that a spatial resolution of 50 μm can be obtained

The micro-gap chamber

Abstract The micro-gap chamber (MGC), a new type of position sensitive proportional gas counter, is introduced. The device is built using microelectronics technology. In this detector the separation between the electrodes collecting the avalanche charge (the anode-cathode gap) is only a few microns. The time it takes to collect the positive ions is therefore very short ( ≈ 10 ns). The speed of the device now equals that of solid state detectors but it is more than three orders of magnitude higher than in standard proportional counters and one order of magnitude higher than in the recently introduced microstrip gas chamber (MSGC). As a result, the rate capability is extremely high (> 9×10 6 c /mm 2 s). The amplifying electric field around the thin anode microstrip extends over a small volume but is very intense (270 kV/mm). It provides a gas gain of 2.5 × 10 3 at 400 V with 14% (FWHM) energy resolution at 5.4 keV. The anode pitch is 100 μm and the readout is intrinsically two-dimensional. Because there is practically no insulating material in view, charging was not observed even at the highest rate. This device seems very well suited for instrumentation of the tracking system at the new hadron colliders (LHC/SSC) as well as in many other fields of research

A microstrip gas chamber with true two-dimensional and pixel readout

A true two-dimensional μstrip gas chamber has been constructed and successfully tested. This new detector has an effective substrate thickness of less than 2 μm. An ion implanted oxide layer of 1.8 μm thickness provides the necessary insulation between the front and back plane and permits collection on the back electrodes of a large fraction of the induced charge. The back electrode signal is used to measure the coordinate along the anode strips (X-Y readout) or to provide true space points (pixel readout). Very good imaging capabilities have been obtained in both cases. A flux of 107 particles/mm2 s has been measured without significant gain loss. No charging effect has been observed after three days continuously running at a flux of 104 particles/mm2 s, while a 15% gain loss, probably due to ageing effects, has been measured after collection on the strips of a charge corresponding to the more than six years of running at the design luminosity of LHC, at 50 cm from the beam axis

Substrate-less, spark-free micro-strip gas counters

Abstract We review recent work involving micro-strip gas counters with "advanced passivated" cathode strips. We present results from tests of a new variation of the MSGC, the planar micro-gap counter (PMGC), with very small ( ∼10 μ m) anode–cathode gap. Gains of up to 3×10 4 were achieved and gain variations due to charging effects were less than 10% using an ordinary (uncoated) boro-silicate glass substrate. The PMGC showed no reduction in gain when subjected to an X-ray flux of 4×10 5 Hz/mm 2 and survived exposure to alpha particles equivalent to 75 days' running at LHC with no signs of strip damage

A thin, large area microstrip gas chamber with strip and pad readout

Abstract The design, construction and test of a thin (200 μm overall substrate thickness), large area (10 cm × 10 cm) microstrip gas chamber (MSGC) with both strip and pad readout is described. The device is built on a 6 in. silicon wafer. The characteristics of this detector make it suitable as a building block of a tracking system at LHC/SSC

Bruno Pontecorvo: un lungo viaggio tra storia e scienza

Mostra su Bruno Pontecorvo. Pisa 8 novembre-11 dicembre 201

An X-ray polarimeter for hard X-ray optics

Development of multi-layer optics makes feasible the use of X-ray telescope at energy up to 60-80 keV: in this paper we discuss the extension of photoelectric polarimeter based on Micro Pattern Gas Chamber to high energy X-rays. We calculated the sensitivity with Neon and Argon based mixtures at high pressure with thick absorption gap: placing the MPGC at focus of a next generation multi-layer optics, galatic and extragalactic X-ray polarimetry can be done up till 30 keV.Comment: 12 pages, 7 figure