On the localization properties of an RPWELL gas-avalanche detector

A study of the localization properties of a single-element Resistive Plate WELL (RPWELL) detector is presented. The detector comprises of a single-sided THick Gaseous Electron Multiplier (THGEM) coupled to a segmented readout anode through a doped silicate-glass plate of 10$^{10}$ $\Omega\cdot$cm bulk resistivity. Operated in ambient Ne/(5$\%$CH$_4$) gas, the detector has been investigated with 150 GeV muons at CERN-SPS. Signals induced through the resistive plate on anode readout strips were recorded with APV25/SRS electronics. The experimental results are compared with that of Monte Carlo simulations. The effects of various physics phenomena on the position resolution are discussed. The measured position resolution in the present configuration is 0.28 mm RMS - compatible with the holes-pattern of the multiplier. Possible ways for improving the detector position resolution are suggested

Time-resolved fast-neutron imaging with a pulse-counting image intensifier

A new imaging method that combines high-efficiency fast-neutron detection with sub-ns time resolution is presented. This is achieved by exploiting the high neutron detection efficiency of a thick scintillator and the fast timing capability and flexibility of light-pulse detection with a dedicated image intensifier. The neutron converter is a plastic scintillator slab or, alternatively, a scintillating fibre screen. The scintillator is optically coupled to a pulse counting image intensifier which measures the 2-dimensional position coordinates and the Time-Of-Flight (TOF) of each detected neutron with an intrinsic time resolution of less than 1 ns. Large-area imaging devices with high count rate capability can be obtained by lateral segmentation of the optical readout channels

Photocathodes for a post-processed imaging array

Preliminary results of a photon detector combining a Micromegas like multiplier coated with a UV-sensitive CsI photocathode are described. The multiplier is made in the CMOS compatible InGrid technology, which allows to post-process it directly on the surface of an imaging IC. This method is aimed at building light-sensitive imaging detectors where all elements are monolithically integrated. We show that the CsI photocathode deposited in the InGrid mesh does not alter the device performance. Maximum gains of ~6000 were reached in a singlegrid element operated in Ar/CH4, with a 2% Ion Back Flow fraction returning to the photocathode

A UV Sensitive Integrated Micromegas with Timepix Readout

This article presents a detector system consisting of three components, a CMOS imaging array, a gaseous-detector structure with a Micromegas layout and a UV-photon sensitive CsI reflective photocathode. All three elements have been monolithically integrated using simple post-processing steps. The Micromegas structure and the CMOS imaging chip are not impacted by the CsI deposition. The detector operated reliably in He/isobutane mixtures and attained charge gains with single photons up to a level of 6 \cdot 10^4. The Timepix CMOS array permitted high resolution imaging of single UV-photons. The system has an MTF50 of 0.4 lp/pixel which corresponds to app. 7 lp/mm.Comment: 4 pages with 8 figures. Submitted to Nucl. Instr. and Meth. A (Elsevier) for proceedings of VCI 2010

Progress with Xenon Liquid Hole Multipliers

The bubble-assisted Liquid Hole Multiplier (LHM) is a recently-proposed concept for the combined detection of ionization electrons and primary scintillation photons in noble-liquid time projection chambers. The LHM comprises a perforated micro-pattern electrode (e.g. Thick Gas Electron Multiplier - THGEM, or Gas Electron Multiplier - GEM) immersed in the liquid, with a bubble of the noble gas supported underneath. Ionization electrons and scintillation-induced photoelectrons extracted from a cesium iodide photocathode drift through the electrode's holes and induce electroluminescence (EL) signals in the bubble; these are recorded by photon detectors located closely below the electrode. We present recent results in the development of LHMs, comparing the response of different electrodes to ionization and photon-induced electrons.Comment: Presented at 2016 IEEE NSS/MIC, Strasbourg, France, 29 October - 5 November 201

An integrated Micromegas UV-photon detector

Preliminary results of a photon detector combining a Micromegas like multiplier coated with a UV-sensitive CsI photocathode are described. The multiplier is made in a CMOS compatible InGrid technology, which allows to post-process it directly on the surface of an imaging IC. This method is aimed at building light-sensitive imaging detectors where all elements are monolithically integrated. We show that the CsI photocathode deposited in the InGrid mesh does not alter the device performance. Maximum gains of ~6000 were reached in a single-grid element operated in Ar/CH4, with a 2% Ion Back Flow fraction returning to the photocathode.Comment: 5 pages with 6 figures. This paper is submitted to Nuclear Instruments and Methods A (Elsevier) for the proceedings of IWORID 2009