Multi-layer thick gas electron multiplier (M-THGEM): A new MPGD structure for high-gain operation at low-pressure

Abstract

The operating principle and performances of the Multi-layer Thick Gaseous Electron Multiplier (M-THGEM) are presented. The M-THGEM is a novel hole-type gaseous electron multiplier produced by multi-layer printed circuit board technology; it consists of a densely perforated assembly of multiple insulating substrate sheets (e.g., FR-4), sandwiched between thin metallic-electrode layers. The electron avalanche processes occur along the successive multiplication stages within the M-THGEM holes, under the action of strong dipole fields resulting from the application of suitable potential differences between the electrodes. The present work focuses on the investigation of two different geometries: a two-layer M-THGEM (either as single or double-cascade detector) and a single three-layer M-THGEM element, tested in various low-pressure He-based gas mixtures. The intrinsically robust confinement of the avalanche volume within the M-THGEM holes provides an efficient reduction of the photon-induced secondary effects, resulting in a high-gain operation over a broad pressure range, even in pure elemental gas. The operational principle, main properties (maximum achievable gain, long-term stability, energy resolution, etc.) under different irradiation conditions, as well as capabilities and potential applications are presented and discussed.

Direct Observation of Proton Emission in Be11

“…This device allows for efficient and high-resolution measurement of very low energy particles. The pAT-TPC consists of a cylindrical gaseous volume of 50 cm length with 12 cm radius with a detection plane composed of a dual micropattern gas detector (Micromegas [18] coupled to a Multi-layer Thick Gas Electron Multiplier [19]). An electric field is applied along the beam axis between the cathode end and the detection plane.…”

The nuclear matrix elements of 0νββ decay and the NUMEN project at INFN-LNS

“…1. change the beam extraction technology from electrostatic deflector to a stripper foil [19]; 2. increase the supplied current of the MAGNEX magnets to reach a higher maximum magnetic rigidity, preserving the geometry and field uniformity of the magnetic fields [20][21] in order to keep the highprecision of the present trajectory reconstruction; 3. install a beam dump to stop the high power beams, keeping the generated radioactivity under control; 4. develop suitable isotopically enriched thin targets to be used in the experiments equipped with a cooling system, which is necessary to dissipate the heat produced by the passage of the intense beam [22]; 5. substitute the present MAGNEX Focal Plane Detector gas tracker, based on multiplication wire technology, with a tracker based on micro patterned gas detector [23][24]; 6. substitute the wall of silicon pad stopping detectors with SiC detectors [25][26] or similar [27] Finally, the development of a specific theory program to allow an accurate extraction of nuclear structure information from the measured cross sections is part of the NUMEN project. Relying on the use of the DWBA approximation for the cross section, the theoretical activity of the project is focused on the development of microscopic models for DCE reactions, employing several approaches (QRPA, shell model, IBM) for inputs connected to nuclear structure quantities.…”

New Results from the NUMEN Project

“…1. The substitution of the present focal plane detector (FPD) gas tracker, based on multiplication wire technology with a tracker system based on micro patterned gas detector [15,16];…”