Charged Particle Detection Research Articles

Particle physics readout electronics and novel detector technologies for neutron science

Traditional thermal neutron detectors are based on Helium-3 as conversion and detection material due to its large neutron cross-section. The difficult availability of this converter and the simultaneous higher demand for neutron detectors lead to the investigation of alternatives. Solid converters with a large thermal cross-section as boron or gadolinium, which emit charged particles when hit by a neutron are a prominent type. Similar to the concepts in particle physics, the techniques then rely on charged particle detection. A prime example is the Gadolinium Gas Electron Multiplier (GdGEM) detector for the NMX instrument at ESS.We present three further novel concepts for neutron detectors. By modifying existing detector principles with a solid converter and employing recent high-granular readout electronics from particle physics we aim at developing thermal neutron detectors beyond the state-of-the-art. The first concept combines the Timepix3 data-driven, self-triggered readout chip with a boronated Micro-Channel Plate. The second concept is a Time Projection Chamber with boronated scintillator walls. The third concept combines boronated segmented GEMs with a VMM3a-based strip readout.This proceeding introduces the novel concepts, outlines how they could go beyond the state-of-the-art, sketches the current progress and obstacles overcome and, where available, presents first measurement results. The project, even though at an intermediate stage, shows the high value of technology transfer between disciplines and the originality required to start such a process.

The PADME charged particle spectrometer

The PADME experiment aims at searching signals of a dark photon A′. This is done evaluating the final state missing mass of the process e + e − → A′γ by knowing the beam energy and measuring the four-momentum of the ordinary recoil photon. The determination of this quantity, and the capability to reject the background, are the key points for the success of the experiment.Three charged particle detectors are employed to detect the positrons that have radiated a high energy photon in the target (PVeto), electrons from the beam interactions in the target or from particles which decay to final states with electrons (EVeto), and the positrons with a relatively low energy radiation in the target (HEPVeto). All three detectors are made of plastics scintillator bars placed inside the vacuum vessel of the PADME setup. PADME Commissioning took place in 2018-2019 with the beam of the Linac of the local Beam Test Facility (BTF) and results and performance of the veto stations will be presented.

Detection of low-energy charged particles by channel electron multipliers

Experimental determinations of the detection efficiency for positrons impacting a channel electron multiplier with incident energies between 0–1400 eV are presented. A log-normal dependence with energy is established and used to compute the positron-to-positronium detection efficiency ratio as a function of positronium energy, as required for determining quantities involving the ratio of positron and positronium rates. A log-normal energy-dependence is also observed in results of previous work with electrons, protons and ions.

Performance of semi-insulating metal-semiconductor-metal GaN prototype devices as ionizing radiation detector

We describe the fabrication and characterization of semi-insulating GaN devices for the detection of ionizing radiation with applications in high radiation environment. We present the DC characterization and the signal response of such devices from Am-241 α-source. The detector prototypes show up to 80% charge collection efficiency with bias voltages as low as -40V. Wide band gap semiconductors like synthetic diamond, GaN, SiC have gained immense importance in the field of charged particle detection due to their low intrinsic noise and high radiation tolerance. The ability of suppressing the thermal noise generated by intrinsic carriers, makes the fabrication of these devices simpler when compared to the multi-step lithography required for doping of traditional silicon-based solid-state detectors. We have made interdigitated metal-semiconductor-metal(MSM) device on a 3μm in thick GaN epitaxial layer grown on sapphire substrate by MOCVD technique. We employed Ni/Pt/Au metal stack for Schottky contact with finger width of 4μm, spacing of 8μm and finger length of 120μm. Details of the experimental set-up for fabrication and characterization will be presented.

Large-Area TKIDs for Charged Particle Detection

Large-Area TKIDs for Charged Particle Detection

A Geant4 Simulation on the Application of Multi-layer Graphene as a Detector Material in High-energy Physics

The excellent properties of graphene, such as its high thermal conductivity, high electrical conductivity, and high electron density, make it an ideal candidate as a detector material in high-energy physics applications. In this work, we demonstrate the feasibility of multi-layer graphene (MLG) as a detector material in a high-energy environment. The Geant4 software package was used to estimate the energy of the deposited electrons within various thicknesses of MLG, ranging from 3 to 20 nm. The efficiency of the MLG as a detector material was further analyzed from the scattering angle and the yield of the secondary particles produced from the electron interaction with the material. The incident electron’s kinetic energy used herein ranged between 30 keV and 1 GeV, at a particle fluence of 1×107 e/cm2. The results show that the deposited energy was relatively low for the interaction with 1 MeV electrons, and dramatically increased as the thickness increases beyond 15 nm. This result was further supported by the highest yield of gamma radiation recorded by the interaction with a kinetic energy larger than 1 MeV, for thickness larger than 15 nm. The results suggest that the MLG works best as a charged particle detector in low energy ranges, while for high energy ranges, a thickness over 15 nm is suggested. The findings demonstrate that a MLG with a thickness larger than 15 nm could potentially be used as a detector material in high-energy conditions.

New trapezoid-shaped Frisch-grid ionization chamber for low-energy particle measurements

A new trapezoid-shaped Frisch-grid ionization chamber (TFG-IC) has been built as a part of a varDelta {E}-E telescope system for the detection and identification of charged particles at energies down to a few MeV. To study the effect of the drift electric field uniformity, two types of sealed windows, namely a pair of SSA (split-strip aluminized mylar film) and a pair of DSA (double-sided aluminized mylar film) sealed windows have been investigated. The detector’s performances were studied using a standard ^{241}Am source at different gas pressures, and the total energy-deposit resolution achieved is about 1.1%(FWHM). The varDelta {E}-E telescope, which was composed of TFG-IC and a DSSSD (double-sided silicon strip detector), has been tested using a three-component alpha source and the ^{241}Am source under laboratory conditions. The results show that the energy resolution with the SSA sealed windows which provide uniform drift electric field has a smaller fluctuation than that with the DSA ones; the fluctuations are about 1% and 4% for the former and the latter, respectively. Simulations using the COMSOL software also confirmed the electric-field distortion at the edge of the detector with the DSA windows. A correlation curve between energy resolution and energy deposit of charged particles at various gas pressures and for two gas species is derived for TFG-IC with the SSA sealed windows using the measurement with the ^{241}Am source. Incorporating the above results, we performed Monte Carlo simulations to evaluate the particle-identification capability of the telescope. The results show that the telescope can be extended to the identification of low-energy particles.

DCR and crosstalk characterization of a bi-layered 24 × 72 CMOS SPAD array for charged particle detection

This paper presents the results from the crosstalk and dark count rate (DCR) characterization of a 24 × 72 single photon avalanche diode (SPAD) array, fabricated in a 150 nm CMOS technology. The chip under test consists of a dual layer detection system developed in view of applications to charged particle tracking. A three step procedure, used for the crosstalk characterization, is presented. The crosstalk probability, taking place in 5 × 5 sub arrays built around noisy pixels, has been computed. Eventually, random telegraph signal (RTS) fluctuations in DCR, at different bias conditions, are briefly discussed.

Optimization of the Composition of Toluene-Based Liquid Scintillator

Scintillators in general and organic liquid scintillator specifically are widely used as a medium for the detection of charged particles for numerous applications in science, medicine, engineering, and other areas. The composition of the scintillator affects not only its direct performance characteristics, but also the overall cost. Optimization of this composition provides the ability to design particle detectors with an optimized light yield and emission spectra of the detection medium while optimizing the expenses at the same time. This article describes work on toluene-based liquid scintillator component optimization, where PPO is used as a fluor and POPOP as a shifter. The light yield vs. concentration and the changes in the output spectra will be presented. The empirical fit of the output spectrum using the measured contributions of the components is discussed. Further plans include the light attenuation measurements for different compositions.

Study on the reusability of fluorescent nuclear track detectors using optical bleaching

Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg crystals are luminescent detectors that can be used for dosimetry and detection of charged particles and neutrons. These detectors can be utilized for imaging applications where a reasonably high track density, approximately of the order of 1×104 tracks in an area of 100 × 100 μm2, is required. To investigate the reusability of FNTDs for imaging applications, we present an approach to perform optical bleaching under the required track density conditions. The reusability was assessed through seven irradiation-bleaching cycles. For the irradiation, the studied FNTD was exposed to alpha-particles from an 241Am radioactive source. The optical bleaching was performed by means of ultraviolet laser light with a wavelength of 355 nm. Three dedicated regions on a single FNTD with different accumulated track densities and bleaching conditions were investigated. After every irradiation-bleaching cycle, signal-to-noise ratio was calculated to evaluate FNTD performance. It is concluded that FNTDs can be reused at least seven times for applications where accumulation of a high track density is required.

Differential cross sections and photon beam asymmetries of η photoproduction on the proton at Eγ=1.3–2.4 GeV

We have carried out exclusive measurements for the photoproduction of an $\eta$ meson from a proton target with an egg-shaped calorimeter made of BGO crystals (BGOegg) and forward charged-particle detectors at the SPring-8 LEPS2 beamline. The differential cross sections and photon beam asymmetries of the $\gamma p \to \eta p$ reaction are measured in a center-of-mass energy ($W$) range of $1.82$-$2.32$ GeV and a polar angle range of $-1.0 < \cos{\theta^{\eta}_{\mathrm{c.m.}}} < 0.6$. The reaction is identified by selecting a proton and two $\gamma$'s produced by an $\eta$-meson decay. The kinematic fit method was employed to select the reaction candidate with the confidence level larger than $1$\%. A bump structure at $W$ = $2.0$-$2.3$ GeV in the differential cross section is confirmed at extremely backward $\eta$ polar angles, where the existing data are inconsistent with each other. This bump structure is likely associated with high-spin resonances that couple with $s\bar{s}$ quarks. The results of the photon beam asymmetries in a wide $\eta$ polar angle range are new for the photon beam energies exceeding $2.1$ GeV. These results are not reproduced by the existing partial wave analyses. They provide an additional constraint to nucleon resonance studies at high energies.

Development of Micro-Pattern Gaseous Detectors for Nuclear Reaction Studies

One of the frontiers of today’s nuclear physics research is the synthesis of Super Heavy Elements (SHE). Fusion-fission dynamics, namely the competition between quasi fission and fusion is one of the key challenges to optimize the SHE. To have an insight into the dynamics, one requires the study of fission fragment mass and angular distribution near barrier energies for heavy-ion induced fission reactions. Recent successful installation of linear accelerators in India offers a unique opportunity to study the dynamics of nuclear reactions and formation process of SHE. For the effective utilization of these current, as well as upcoming facilities, development of novel detectors to study reaction dynamics, formation process of SHE with heavier projectiles and higher beam energies is needed. Gaseous detectors have undergone a rapid improvement in terms of spatial, temporal and energy resolution, rate capability, radiation hardness, ion feedback etc., ushering in a new genre of micro-structured devices based on semi-conductor technology, commonly known as Micro-Pattern Gaseous Detectors (MPGDs). Although many of the MPGD structures were primarily developed for high-rate tracking of charged particles in high energy physics experiments, stability of operation, simplicity of construction and relatively low cost make these detectors suitable for other applications, such as low-energy nuclear physics experiments. The present activities encompass a detailed evaluation of the operational conditions of Micromesh-Multi Wire and THGEM-Multi Wire hybrid detector operated in low-pressure isobutane gas with a view to optimizing their use in the detection of charged particles and fission fragments.

Measuring Atmospheric Radon Levels Using a Cloud Chamber

The Wilson cloud chamber, invented in 1911 by Scottish physicist Charles Wilson, is a remarkably simple and effective charged particle detector. Cloud chambers were used regularly in particle physics experiments for decades, until being supplanted by bubble chambers. In this article, we describe a lab activity that is suitable for introductory-level physics students using a cloud chamber to measure the rate of alpha decay in the atmosphere. In performing this experiment, the students deepen their understanding of alpha decay, including the random nature of the process. They also become acquainted with statistical uncertainties from measuring a random process.

“RIPTIDE” — an innovative recoil-proton track imaging detector

Neutron detectors perform key tasks in many research fields as nuclear, particle and astroparticle physics as well as neutron dosimetry, radiotherapy, and radiation protection. Neutron detectors exhibiting tracking capability are still missing, although several approaches to neutron momentum reconstruction have been proposed. In this context, we aim at developing a novel RecoIl-Proton Track Imaging DEtection system “RIPTIDE”, in which the light output of a fast scintillation signal is used to perform a complete reconstruction in space and time of the neutron-proton elastic scattering. The 3D track reconstruction is going to be implemented by state-of-the-art high-sensitivity imaging detector (CMOS, MCP-Timepix). Preliminary Geant4 simulations of the proposed set-up show up a good detection efficiency in a compact active volume. The envisaged electronic readout can be easily adapted according to a specific application (event-by-event mode or integration mode). The system can be rescaled by increasing the detection volume or by combining several detection modules. Further developments of the basic detection technique can be adapted for fast charged particle detection tracking as well.

Effect of the Synthesis Conditions on the Morphology, Luminescence and Scintillation Properties of a New Light Scintillation Material Li2CaSiO4:Eu2+ for Neutron and Charged Particle Detection

In the present article, the influence of the activator concentration and impurity content of raw materials on the luminescence and scintillation properties of Li2CaSiO4 was studied. Polycrystalline powder material was obtained by the sol–gel method. It was shown that europium had limited solubility in the host lattice with a limiting concentration proximate to 0.014 formula units. The maximum intensity of photoluminescence was observed with a divalent europium concentration of 0.002 formula units; the light yield under alpha-particle excitation was measured to be 21,600 photons/MeV for ~200 μm of coating, and under neutron excitation, it was calculated to be 103,800 photons/n, the scintillation kinetics was characterized by an effective decay time of 157 ns. These properties and the transparency in the visible spectrum make it possible to produce scintillation screens with a coating of Li2CaSiO4 for detecting neutrons, alpha particles and low-energy beta radiation. The low Zeff (~15) of this compound makes it less sensitive to gamma rays. The 480 nm blue emission peak makes this material compatible with most commercial PMT photocathodes, CCD cameras and silicon photomultipliers, which have a maximum quantum efficiency in the blue–green spectral region.

4D tracking: present status and perspectives

The past ten years have seen the advent of silicon-based precise timing detectors for charged particle tracking. The underlying reason for this evolution is a design innovation: the Low-Gain Avalanche Diode (LGAD). In its simplicity, the LGAD design is an obvious step with momentous consequences: low gain leads to large signals maintaining sensors stability and low noise, allowing sensor segmentation. Albeit introduced for a different reason, to compensate for charge trapping in irradiated silicon sensors, LGAD found fertile ground in the design of silicon-based timing detectors. Spurred by this design innovation, solid-state-based timing detectors for charged particles are going through an intense phase of R&D, and hybrid and monolithic sensors, with or without internal gain, are being explored. This contribution offers a review of this booming field.

Charge sensing properties of monolithic CMOS pixel sensors fabricated in a 65 nm technology

In this work the initial performance studies of the first small monolithic pixel sensors dedicated to charged particle detection, called CE-65, fabricated in the 65nm TowerJazz Panasonic Semiconductor Company are presented. The tested prototypes comprise matrices of 64×32 square analogue-output pixels with a pitch of 15μm. Different pixel types explore several sensing node geometries and amplification schemes, which allows for various biasing voltage of the detection layer and hence depletion conditions and electric field shaping. Laboratory tests conducted with a 55Fe source demonstrated that the CE-65 sensors reach equivalent noise charge in the 15 to 25e− range and excellent charge collection efficiencies. Charge sharing is substantial for standard diodes, but can be largely suppressed by modifying their design. Depletion of the thin sensitive layer saturates at a reverse diode bias of about 5 V.

Direct detection of charged particles with SiPMs

The direct response of Silicon PhotoMultipliers being traversed by a MIP charged particle have been studied in a systematic way for the first time. Using beam test data, time resolution and the crosstalk probability have been measured. A characterization of the SiPM by means of a laser beam is also reported. The results obtained for different sensors indicate a measured time resolution around 40–70 ps. Although particles are expected to traverse only one SPAD per event, crosstalk measurements on different sensors indicate an unexpected higher value with respect to the one related to the sensor noise.

Space Weather Effects from Observations by Moscow University Cubesat Constellation

Moscow State University is developing a project for a multi-satellite constellation intended for the monitoring of space radiation. A number of small satellites of CubeSat format were launched into selected orbits crossing the wide range of magnetic drift shells. The primary scope for the project is the operational monitoring of near-Earth’s radiation environment, i.e., fluxes of electrons and protons of Earth’s radiation belts and energetic particles of solar and galactic origin. To date, there are four CubeSat satellites operating in near-Earth orbits, which deliver scientific and telemetric data. Thus, for the first time, a unique multi-satellite constellation has been implemented, which makes it possible to simultaneously measure the particle and quantum fluxes at different areas in the near-Earth space using the same type of instruments. A special compact detector of gamma quanta and energetic charged particles (electrons and protons) DeCoR has been developed to carry out radiation monitoring by CubeSats. With their help, observations of various effects of space weather have been made. These effects include a variety of electron fluxes in the outer belt during geomagnetic activity in late November–early December 2021, filling of polar caps by solar energetic particles accelerated in flares occurring in late October–early November, and the existence of stable electron fluxes near the geomagnetic equator.

Analytical view on topological defects of superconducting order parameter in various topologies of nanowires with focus on quantum detectors and Josephson junctions

The analysis of superconducting nanowires placed in different electromagnetic environments is presented in the framework of Ginzburg-Landau model. First domain of application of conducted analysis is noninvasive superconducting detectors of charged particles and robust field induced Josephson junctions. Robust field induced Josephson junctions (rFIJJs) made by polarization of superconducting nanostructures by external magnetic fields are presented in one dimensional model. The analytical methodology of modeling of rFIJJs in one dimensional cases is introduced and possible implementations are pointed by reference to the principle of minimization of magnetic field energy that is preimposing the space dependence of the screening currents. The presented schemes have potential in description both classical and quantum computers with use of topological defects of superconducting order parameter and artificial evolution. Scheme of testing new topologies and working parameters of circuits is given what shall imply enhancement of already known circuit schemes. Furthermore concept of noninvasive superconducting detectors is given as sensing device for moving charged particles as in accelerator beam or in nano-accelerator beam. Obtained results are refereeing to functionalization of superconducting nanowires topology with reference to various programmable biasing magnetic fields that incorporates the concept of programmable superconducting matter. The presented conceptual scheme can also be used for designing the experiments, where Bose-Einstein condensate is being biased with various class of topologies of magnetic fields coming from three dimensional meta-lattice of superconducting nanowires.