arXiv subjects

Marco Cortesi

Publications and source records attributed to Marco Cortesi.

13 recordsLinked to original sources

arXiv2026

Two-dimensional Optical Parallel-Plate Avalanche Counter (OPPAC) with SiPM optical readout for heavy-ion tracking

We report the progress achieved on the development of a two-dimensional Optical Parallel-Plate Avalanche Counter (OPPAC) prototype for heavy-ion tracking. The device consists of two uniform thin parallel plates of 10 x 10 cm2 effective area, separated by a gap of 3 mm. The gap is filled with Tetrafluoromethane (CF4) at low pressure (up to 50 Torr). By applying a voltage difference between parallel plates, a uniform electric field is established within the gap. Electroluminescence emission is produced during the electron avalanche triggered by a charged particle that crosses the gas gap. The light is detected by an optical readout comprising four arrays of collimated Silicon Photomultipliers (SiPMs) deployed around the gas gap. The position of the particles is reconstructed by processing the light signals collected by all the SiPMs by computing the center of gravity of the light distribution within the SiPM arrays. The SiPM signals are read out and processed by a data acquisition (DAQ) system based on the General Electronics for TPC (GET). Preliminary results from a test with an alpha-particle source and a 100 MeV/u 40Ca beam demonstrate a sub-millimetre intrinsic position resolution sigma_det = 0.7 mm) while preserving good linearity over the entire detector active area.

physics.ins-det↗

arXiv2025

$\beta$-delayed proton pandemonium: A first detailed $^{31}$Cl($\beta p \gamma$)$^{30}$P decay scheme

Positron decays of proton-rich nuclides exhibit large $Q$ values, producing complex cascades which frequently involve various radiations, including protons and $\gamma$ rays. Often, only one of the two is measured in a single experiment, limiting the accuracy and completeness of the decay scheme. An example is $^{31}$Cl, for which protons and $\gamma$ rays have been measured separately in detail but never with substantial sensitivity to proton-$\gamma$ coincidences. We provide detailed measurements of $^{31}$Cl $\beta$-delayed proton decay including $\beta$-$p$-$\gamma$ sequences, extract spectroscopic information on $^{31}$S excited states as well as their $\beta^+$ feedings, and compare to shell-model calculations. A fast fragmented beam of $^{31}$Cl provided by the National Superconducting Cyclotron Laboratory (NSCL) was deposited in the Gaseous Detector with Germanium Tagging (GADGET) system. GADGET's gas-filled Proton Detector was used to detect $\beta$-delayed protons, and the Segmented Germanium Array (SeGA) was used to detect $\beta$-delayed $\gamma$ rays. As many as 20 previously unobserved $\beta$-delayed proton transitions are reported, most of which populate excited states of $^{30}$P. The first detailed $^{31}$Cl($\beta p \gamma$)$^{30}$P decay scheme is presented, including updated $\beta$-delayed proton energies and intensities, as well as several new $^{31}$S levels. Improved agreement is found with theoretical calculations of the Gamow-Teller strengths $B(\text{GT})$ for $^{31}$S excitation energies $7.5 < E_x < 9.5$ MeV. The present work demonstrates that the ability to detect $\beta$-delayed protons and $\gamma$ rays in coincidence is essential for accurate positron decay schemes to compare with nuclear structure theory. This phenomenon for $\beta$-delayed protons resembles the pandemonium effect originally introduced for $\beta$-delayed $\gamma$ rays.

nucl-ex↗

arXiv2022

Snowmass 2021 Instrumentation Frontier (IF5 - MPGDs) -- White Paper 2: Micro Pattern Gaseous Detectors for Nuclear Physics

Many current and future nuclear physics (NP) experiments across the United States have and are implementing micro-pattern gas detectors (MPGDs) to be used for tracking and PID purposes. MPGDs are capable of operating in high rate environments and providing excellent spatial resolution over a large-area with a low material budget. Summarized in this white paper is the role that MPGDs are playing in NP experiments and the R&D which is needed to meet the requirements of future NP experiments.

physics.ins-det↗

arXiv2019

Development of the TIP-HOLE gas avalanche structure for nuclear physics/astrophysics applications with radioactive isotope beams: preliminary results

We discuss the operational principle and performance of new micro-pattern gaseous detectors based on the multi-layer Thick Gaseous Electron Multiplier (M-THGEM) concept coupled to a needle-like anode. The new gas avalanche structure aims at high-gain operation in nuclear physics and nuclear astrophysics applications with radioactive isotope beams. It is thereafter named TIP-HOLE gas amplifier, and consists of a THGEM or a two-layers M-THGEM mounted in a WELL configuration. The avalanche electrodes are collected by thin conductive needles (with up to a few ten um radius and a height of 100 um), located at the center of the hole and acting as point-like anode. The bottom area of the needle may be surrounded by a cylindrical cathode strip in order to increase the electron collection efficiency. The electric field lines from the drift region above the M-THGEM are focused into the holes, and then forced to converge on the needle tip. An extremely high field is reached at the top of the needle, creating a point-like avalanche process. Stable, high-gain operations in a wide range of pressures may be achieved at relatively low operational voltage, even in pure quencher gas at atmospheric pressure (e.g. pure isobutene). The TIP-HOLE structure may be produced by the innovative scalable additive manufacturing technology for large-area, multiple-layer printed circuit boards, recently developed by the UHV technology company (USA) and discussed for the first time in this work.

physics.ins-det↗

arXiv2019

GADGET: A Gas Amplifier Detector with Germanium Tagging

The Gas Amplifier Detector with Germanium Tagging (GADGET) is a new detection system devoted to the measurement of weak, low-energy $β$-delayed proton decays relevant for nuclear astrophysics studies. It is comprised of a new gaseous Proton Detector equipped with a Micromegas readout for charged particle detection, surrounded by the existing Segmented Germanium Array (SeGA) for the high-resolution detection of the prompt $γ$-rays. In this work we describe in detail for the first time the design, construction, and operation of the GADGET system, including performance of the Proton Detector. We present the results of a recent commissioning experiment performed with \textsuperscript{25}Si beam at the National Superconducting Cyclotron Laboratory (NSCL). GADGET provided low-background, low-energy $β$-delayed proton detection with efficiency above 95\%, and relatively good efficiency for proton-gamma coincidences (2.7\% at 1.37 MeV).

physics.ins-det↗

arXiv2018

Development of a Parallel-Plate Avalanche Counter with Optical Readout (O-PPAC)

We describe a novel gaseous detector concept for heavy-ion tracking and imaging: the Optical Parallel-Plate Avalanche Counter (O-PPAC). The detector consists of two thin parallel-plate electrodes separated by a small (typically 3 mm) gap filled with low-pressure scintillating gas (i.e. CF4). The localization of the impinging particles is achieved by recording the secondary scintillation, created during the avalanche processes within the gas gap, with dedicated position-sensitive optical readouts. The latter may comprise arrays of collimated photo-sensors (e.g. SiPMs) that surround the PPAC effective area. We present a systematic Monte Carlo simulation study used to optimize the geometry of the OPPAC components, including SiPMs effective area, collimator dimensions, and operational conditions. It was found that the optimal design for 10x10 cm^2 OPPAC detector comprises four arrays, each of them counting a total of 15-20 individual photo-sensors. This configuration provides a localization capability with a resolution below 1 mm and good response uniformity. An experimental investigation successfully demonstrated the proof of principle stage of an O-PPAC prototype equipped with a single array of 10 photo-sensors, separated by 6 mm. The performance of the prototype was investigated with an LED light, under 10-,12-C beam irradiation, and with a low-intensity 241-Am alpha-particle source. The experimental data obtained with the prototype is compared to the results obtained by systematic Monte Carlo simulations.

physics.ins-det↗

arXiv2018

First performance evaluation of a Multi-layer Thick Gaseous Electron Multiplier with in-built electrode meshes - MM-THGEM

We describe a new micro-pattern gas detector structure comprising a multi-layer hole-type multiplier (M-THGEM) combined with two in-built electrode meshes: the Multi-Mesh THGEM-type multiplier (MM-THGEM). Suitable potential differences applied between the various electrodes provide an efficient collection of ionization electrons within the MM-THGEM holes and a large charge avalanche multiplication between the meshes. Different from conventional hole-type multipliers (e.g. Gas Electron Multipliers - GEMs, Thick Gas Electron Multipliers - THGEMs, etc.), which are characterized by a variable (dipole-like) field strength inside the avalanche gap, electrons in MM-THGEMs are largely multiplied by a strong uniform field established between the two meshes, like in the parallel-plate avalanche geometry. The presence of the two meshes within the holes allows for the trapping of a large fraction of the positive ions that stream back to the drift region. A gas gain above 10^5 has been achieved for single photo-electron detection with a single MM-THGEM in Ar/(10%)CH4 and He/(10%)CO2, at standard conditions for temperature and pressure. When the MM-THGEM is coupled to a conventional THGEM and used as first cascade element, the maximum achievable gains reach values above 10^6 in He/(10%)CO2, while the IBF approaches of 1.5% in the case of optimum detector-bias configuration. This IBF value is several times lower compared to the one obtained by a double GEM/THGEM detector (5-10%), and equivalent to the performance attained by a Micromegas detector.

physics.ins-det↗

arXiv2015

Recent advances with a hybrid micro-pattern gas detector operated in low pressure H2 and He, for AT-TPC applications

In view of a possible application as a charge-particle track readout for an Active-Target Time Projection Chamber (AT-TPC), the operational properties and performances of a hybrid Micro-Pattern Gaseous Detector (MPGD) were investigated in pure low-pressure Hydrogen (H2) and Helium (He). The detector consists of a MICROMesh GAseous Structure (MICROMEGAS) coupled to a single- or multi-cascade THick Gaseous Electron Multiplier (THGEM) as a pre-amplification stage. This study reports of the effective gain dependence of the hybrid-MPGD at relevant pressure (in the range of 200-760 torr) for different detector arrangements. The results of this work are relevant in the field of avalanche mechanism in low-pressure, low-mass noble gases, in particularly for applications of MPGD end-cap readout for active-target Time Projection Chambers (TPC) in the field of nuclear physics and nuclear astrophysics.

physics.ins-det↗

arXiv2015

Studies of THGEM-based detector at low-pressure Hydrogen/Deuterium, for AT-TPC applications

We study the performance of single- and double- THick Gas Electron Multiplier (THGEM) detectors in pure Hydrogen and Deuterium at low pressures, in the range of 100-450 Torr. The effect of the pressure on the maximum achievable gain, ion-back flow and long-term gain stability are investigated for single and double cascade detectors. In particular, it was found that maximum achievable gains above 10^4, from single-photoelectrons avalanche, can be achieved for pressures of 200 Torr and above; for lower pressure the gains are limited by avalanche-induced secondary effects to a values of around 103. The results of this work are relevant in the field of avalanche mechanism in low-pressure, low-mass noble gases, in particular for applications of THGEM end-cap readout for active-target Time Projection Chambers (TPC) in the field of nuclear physics and nuclear astrophysics.

physics.ins-det↗

arXiv2015

Operation of a THGEM-based detector in low-pressure Helium

In view of a possible application as a charge-particle track readout for an Active Target Time Projection Chamber (AT-TPC), the operating properties of THick Gaseous Electron Multipliers (THGEM) in pure low-pressure Helium were investigated. This paper includes the effective gain dependence on pressure for different detector configurations (single-, double-, triple-cascade setup), long-term gain stability and energy resolution from tracks of 5.5 MeV alpha particles. Stable operational conditions and maximum detector gains of 10^4-10^7 have been achieved in pure Helium at pressure ranging from 100 torr up to 760 torr. Energy resolution of 6.65% (FWHM) for 690 keV of energy deposited by 5.5 MeV alpha particles at 350 torr was measured. The expected energy resolution for the full track is around 2.4% (FWHM). These results, together with the robustness of THGEM electrodes against spark damage, make THGEM structures highly competitive compared to other technologies considered for TPC applications in an active target operating with pure noble gases, requiring a high dynamic range and a wide operating pressure range down to few hundred torr.

physics.ins-det↗

arXiv2011

Hybrid Multi Micropattern Gaseous Photomultiplier for detection of liquid-xenon scintillation

Gaseous PhotoMultipliers (GPM) are a very promising alternative of vacuum PMTs especially for large-size noble-liquid detectors in the field of Functional Nuclear Medical Imaging and Direct Dark Matter Detection. We present recent characterization results of a Hybrid-GPM made of three Micropattern Gaseous Structures; a Thick Gaseous Electron Multiplier (THGEM), a Parallel Ionization Multiplier (PIM) and a MICROMesh GAseous Structure (MICROMEGAS),operating in Ne/CF4 (90:10). Gain values close to 10^7 were recorded in this mixture, with 5.9keV x-rays at 1100 mbar, both at room temperature and at that of liquid xenon (T = 171K). The results are discussed in term of scintillation detection. While the present multiplier was investigated without photocathode, complementary results of photoextraction from CsI UV photocathodes are presented in Ne/CH4 (95:5) and CH4 in cryogenic conditions.

physics.ins-det↗

arXiv2010

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.

physics.ins-det↗

arXiv2008

Time resolution of a Thick Gas Electron Multiplier (THGEM) - based detector

The time resolution of a double-stage Thick-GEM (THGEM) detector was measured with UV-photons and relativistic electrons. The photon detector, with semitransparent- or reflective-photocathode yielded time resolution of about 8-10ns RMS for single photoelectrons and 0.5-1ns RMS for few-hundred photoelectrons per photon-pulse. Time resolution of about 10ns RMS was recorded for relativistic electrons from a 106Ru source.

physics.ins-det↗