Cern-european Organization for Nuclear Research

Organisation Europeenne Pour La Recherche Nucleaire

European Organisation for Nuclear Research-cern

Rui De Oliveira

Ioannis Giomataris

Serge Duarte Pinto

Vladimir Peskov

Antonio Di Mauro

A detector-readout interface for an avalanche particle detector comprises a resistive layer formed at a bottom side of a gas chamber and a dielectric layer formed under said resistive layer and is adapted for capacitive coupling to an external readout board. This provides a modular detector configuration in which the readout card and detector core can be combined freely and interchangeably. The readout board can even be removed or replaced without switching off the detector. At the same time, the configuration provides an effective protection against sparks and discharges, and in particular obliviates the need for additional protecting circuits. The configuration may be employed in any avalanche particle detector, such as the MicroMegas or GEM detectors.

Detector-readout interface for an avalanche particle detector

The invention relates to an improved method for fabricating the amplification gap of an avalanche particle detector in which two parallel electrodes are spaced apart by dielectric spacer elements. A foil including a bulk layer made of dielectric material sandwiched by two mutually parallel metallic electrodes is provided, and holes are formed in one of the metallic layers by means of photolithography. The amplification gap is then formed in the bulk layer by means of carefully controlled etching of the bulk material through the holes formed in one of the metallic layers. The invention not only provides a simplified fabrication process, but also results in a detector with enhanced spatial and energy resolution.

Method for fabricating an amplification gap of an avalanche particle detector

The readout electrode assembly of an avalanche particle detector can be effectively protected against sparks and discharges by means of a plurality of resistor pads formed in a dielectric cover layer above the readout pads. The resistor pads may either be connected directly to the readout pads, or may be coupled capacitively by means of a charge spreading pad embedded into the dielectric cover layer and spatially separated from the readout pads. The charge spreading pad allows the distribution of charges to neighboring readout pads, and may hence increase the spatial resolution of the detector device.

Protected readout electrode assembly

Methods for manufacturing a gas electron multiplier. One method comprises a step of preparing a blank sheet comprised of an insulating sheet with first and second metal layers on its surface, a first metal layer hole forming step in which the first metal layer is patterned by means of photolithography, such as to form holes through the first metal layer, an insulating sheet hole forming step, in which the holes formed in the first metal layer are extended through the insulating layer by etching from the first surface side only, and a second metal layer hole forming step, in which the holes are extended through the second metal layer. Alternatively, the second metal layer hole forming step is performed by electrochemical etching, such that the first metal layer remains unaffected during etching of the second metal layer. In another embodiment, in the second metal layer hole forming step, the first and second metal layers are etched from the outside, thereby reducing the initial thicknesses of the first and second metal layers and the second metal layer is simultaneously etched through the holes in the first metal layer and the insulating sheet, said etching being maintained until the holes extend through the second metal layer, wherein said initial average thickness of the first and second metal layers is between 6.5 &#x3bc;m and 25 &#x3bc;m, preferably between 7.5 &#x3bc;m and 12 &#x3bc;m.

Method of manufacturing a gas electron multiplier

A readout board for use in a micropattern gas detector comprises a plurality of detector pads arranged into a plurality of consecutive layers that are separated by dielectric spacer material. An electron cloud hitting the front side of the readout board will induce a charge on one of the detector pads of the uppermost layer. By capacitive coupling, the signal will propagate downwards through the consecutive layers until it reaches the bottom layer, from which the charges are read out and analyzed. The position of the impact can be determined by comparing the charges that have spread to neighboring readout pads. Since only the bottommost layer of the readout pads needs to be connected to readout electronics, incident particles can be localized at high precision despite the relatively large size of the readout pads in the bottom layer. The invention is effective both in a gas electron multiplier (GEM) and in a MicroMegas detector.

Capacitive spreading readout board

The invention concerns a method for making a multilayer module with high-density printed circuits, which consists in: preparing a substrate () with double-sided printed circuits () whereon is bonded a single-sided plated () polyimide () additional layer using a polymerisable two-phase epoxy liquid (); after selectively etching () the metal, carrying out anisotropic chemical drilling of micro-holes () through the polyimide film () by immersing the latter in a static bath of a potassium-added aqueous ethylene-diamine solution at least at 25&#xb0; C.; rinsing the adhesive () by spraying a solvent in the base of the micro-holes (); plating the micro-holes (); and selectively etching the outer metallic film () to form therein printed circuits () including the plated micro-holes ().

Growing community of inventors

Arenthon, France

Rui De Oliveira