Particle Identification Techniques Research Articles

Peak-CNN: improved particle image localization using single-stage CNNs

AbstractAn important step in the application of Lagrangian particle tracking (LPT) or in general for image-based single particle identification techniques is the detection of particle image locations on the measurement images and their sub-pixel accurate position estimation. In case of volumetric measurements, this constitutes the first step in the process of recovering 3D particle positions, which is usually performed by triangulation procedures. For two-component 2D measurements, the particle localization results directly serve as input to the tracking algorithm. Depending on the quality of the image, the shape and size of the particle images and the amount of particle image overlap, it can be difficult to find all, or even only the majority, of the projected particle locations in a measurement image. Advanced strategies for 3D particle position reconstruction, such as iterative particle reconstruction (IPR), are designed to work with incomplete 2D particle detection abilities but even they can greatly benefit from a more complete detection as ambiguities and position errors are reduced. We introduce a convolutional neural network (CNN) based particle image detection scheme that significantly outperforms current conventional approaches, both on synthetic and experimental data, and enables particle image localization with a vastly higher completeness even at high image densities.

Design and Application of an Onboard Particle Identification Platform Based on Convolutional Neural Networks

Space radiation particle detection plays a crucial role in scientific research and engineering practice, especially in particle species identification. Currently, commonly used in-orbit particle identification techniques include telescope methods, electrostatic analysis time of flight (ESA × TOF), time-of-flight energy (TOF × E), and pulse shape discrimination (PSD). However, these methods usually fail to utilize the full waveform information containing rich features, and their particle identification results may be affected by the random rise and fall of particle deposition and noise interference. In this study, a low-latency and lightweight onboard FPGA real-time particle identification platform based on full waveform information was developed utilizing the superior target classification, robustness, and generalization capabilities of convolutional neural networks (CNNs). The platform constructs diversified input datasets based on the physical features of waveforms and uses Optuna and Pytorch software architectures for model training. The hardware platform is responsible for the real-time inference of waveform data and the dynamic expansion of the dataset. The platform was utilized for deep learning training and the testing of the historical waveform data of neutron and gamma rays, and the inference time of a single waveform takes 4.9 microseconds, with an accuracy rate of over 97%. The classification expectation FOM (figure-of-merit) value of this CNN model is 133, which is better than the traditional pulse shape discrimination (PSD) algorithm’s FOM value of 0.8. The development of this platform not only improves the accuracy and efficiency of space particle discrimination but also provides an advanced tool for future space environment monitoring, which is of great value for engineering applications.

Transition radiation detectors for hadron separation in the forward direction of LHC experiments

Studies in many areas of particle and astroparticle physics require a good knowledge of hadron spectra produced at small angles to the primary particle direction, e.g. in the TeV energy range at the LHC. The present work is dedicated to development of a particle identification technique based on the transition radiation produced by highly relativistic particles. Dedicated experimental studies were carried out and simulation models were developed to reproduce experimental data obtained with different prototypes. On the basis of these studies, the possibility of making detectors able to provide hadron composition measurement with high accuracy and identify particles with high efficiency in the forward experiments at the LHC was demonstrated. Two concepts of large scale TRDs are proposed: the straw TRD and the GaAs/straw TRD. They allow the reconstruction of hadron spectra with accuracy about or below 1% and to identify particles with high efficiency in individual events. As an example, suppression of the combinatorial background was demonstrated for the D0→K−π+ and D̄0→K+π− decays.

Recent Progress in the Study of the Reaction 70Zn (15 MeV/nucleon) + 64Ni with the MAGNEX Spectrometer

The present paper is focused on our recent efforts to study the production and identification of neutron-rich medium-mass rare isotopes from peripheral reactions at beam energies around and below the Fermi energy. We obtained high-quality experimental data from a recent experiment with the MAGNEX spectrometer at the INFN-LNS in Catania, Italy. The main aim of this experiment was to check the feasibility of ejectile identification in this energy regime with the use of a large acceptance magnetic spectrometer. Our developed technique for particle identification depends mainly on a reconstruction of both the atomic number Z and the ionic charge q of the ions, followed by the identification of the mass. Our method was successfully applied to identify neutron-rich ejectiles from multinucleon transfer from the reaction of 70Zn (15 MeV/nucleon) + 64Ni. Preliminary results indicate that the extracted experimental distributions, along with comparisons with the theoretical models could help us to shed light to the complex reaction mechanism of multinucleon transfer in this energy regime.

J/ψ Near-Threshold Photoproduction off the Proton and Neutron with CLAS12

Near-threshold J/ψ photoproduction is a key aspect of the physics program at the Thomas Jefferson National Accelerator Facility (JLab) 12 GeV upgrade due to the wealth of information it has to offer. J/ψ photoproduction proceeds through the exchange of gluons in the t-channel and is expected to provide unique insight about the nucleon gravitational form factors and the nucleon mass radius. The JLab based CLAS Collaboration, which uses the CEBAF Large Acceptance Spectrometer (CLAS12), aims to measure the J/ψ near threshold photoproduction cross section using both a proton and a deuteron target, from threshold up to 10.6 GeV. The deuteron target further offers the possibility of comparing the proton and neutron gluonic form factors and mass radii in a first measurement of the cross sections off a proton or neutron within the deuteron target. The analysis towards these measurements is ongoing and well advanced, with machine learning based techniques for particle identification already designed and validated with CLAS12 data.

Spectroscopic analysis of the gaseous argon scintillation with a wavelength sensitive particle detector

We performed a time-resolved spectroscopic study of the VUV/UV scintillation of gaseous argon as a function of pressure and electric field, by means of a wavelength sensitive detector operated with different radioactive sources. Our work conveys new evidence of distinctive features of the argon light which are in contrast with the general assumption that, for particle detection purposes, the scintillation can be considered to be largely monochromatic at 128 nm (second continuum). The wavelength and time-resolved analysis of the photon emission reveal that the dominant component of the argon scintillation during the first tens of ns is in the range [160, 325] nm. This light is consistent with the third continuum emission from highly charged argon ions/molecules. This component of the scintillation is field-independent up to 25 V/cm/bar and shows a very mild dependence with pressure in the range [1, 16] bar. The dynamics of the second continuum emission is dominated by the excimer formation time, whose variation as a function of pressure has been measured. Additionally, the time and pressure-dependent features of electron-ion recombination, in the second continuum band, have been measured. This study opens new paths toward a novel particle identification technique based on the spectral information of the noble-elements scintillation light.

Recent results for the one-proton transfer reaction in the 18O+48Ti collision at 275 MeV

The 18O+48Ti reaction was studied at the energy of 275 MeV for the first time under the NUMEN and NURE experimental campaigns with the aim to investigate the complete net of reaction channels potentially involved in the 48Ca→48Ti double charge exchange transition. Such a transition is of great interest because of its relevance to the extraction of 48Ca→48Ti double beta decay nuclear matrix element. The relevant experiment was carried out at the MAGNEX facility of INFN-LNS in Catania. Angular distribution measurements for the various reaction products were performed by using the MAGNEX large acceptance magnetic spectrometer. The present contribution is focused on the analysis of the one-proton transfer channel with emphasis on the particle identification technique and the estimation of background contaminations.

A concept of the transition radiation detector for a hadron separation in a forward direction of the LHC experiments

Studying of hadron production in forward direction at the LHC energy has a great interest both for understanding of the fundamental QCD processes and also in applied areas such as the description of ultra-high energy cosmic particle interactions. The energies of secondary hadrons in such studies almost reach the maximum energy available at the LHC of ~6 TeV, which corresponds to a Lorentz γ-factor up to 104 and above. The only effective technique able to identify particles in this range is based on the transition radiation detectors (TRD). Prototypes of such kind of detector were built and tested at the CERN SPS accelerator. Some experimental results obtained in these tests are briefly presented here and compared with Monte Carlo (MC) simulations. MC model demonstrates a good agreement with the experiment. On this basis a concept of a full-scale TRD optimized for the hadron identification in the TeV energy region is proposed. Different particle identification techniques were considered and examined. The expected detector performance to reconstruct secondary hadrons produced in forward direction at the LHC is presented.

Design and construction of MuTe: a hybrid Muon Telescope to study Colombian volcanoes

We present a hybrid Muon Telescope, MuTe, designed and built for imaging active Colombian volcanoes. The MuTe has a resolution of tens of meters, low power consumption, robustness and transportability making it suitable for using in difficult access zones where active volcanoes usually are. The main feature of MuTe is the implementation of a hybrid detection technique combining two scintillation panels for particle tracking and a Water Cherenkov Detector for filtering background signals due to the electromagnetic component of extended air showers and multiple particle events. MuTe incorporates particle-identification techniques for reducing the background noise sources and a discrimination of fake events by a picosecond Time-of-Flight system. We also describe the mechanical behavior of the MuTe during typical tremors and wind conditions at the observation place, as well as the frontend electronics design and power consumption.

Analysis of the background on cross section measurements with the MAGNEX spectrometer: The (20Ne, 20O) Double Charge Exchange case

The MAGNEX magnetic spectrometer is used in the experimental measurements of Double Charge Exchange and Multi-Nucleon Transfer reactions induced by heavy ions within the NUMEN project. These processes are characterized by small cross sections under a large background due to other reaction channels. Therefore an accurate control of the signal to background ratio is mandatory. In this article, the determination of the MAGNEX spectrometer background contribution on cross section measurements is presented by applying a suitable analysis to quantify the limits of the adopted particle identification technique. The method is discussed considering the 116Cd(20Ne, 20O)116Sn Double Charge Exchange reaction data, however it can be applied to any other reaction channel of interest.

Preface

The present volume of Journal of Physics: Conference Series collects the proceedings of contributions presented and discussed during the International Workshop DeSyT2019 (Detection Systems and Techniques in nuclear and particle physics) held from 11 to 13 September, 2019 in Messina (Italy). The scientific event was organized by:• Università degli Studi di Messina;• Istituto Nazionale di Fisica Nucleare - Sez. di Catania;• Accademia Peloritana dei Pericolanti;• Associazione Italiana di Fisica Medica.This event has been conceived in order to stimulate interactions and collaborations.between scientists working in different fields of science which involve particle.detection.It took place in the fascinating and suggestive library room of the Accademia Peoloritana dei Pericolanti. Library room of the Accademia Peoloritana dei Pericolanti; picture taken during a workshop talk.During the workshop more than twenty oral presentations have been discussed on the following topics:• Detectors;• Particle Identification Techniques;• Tracking Systems;• Simulation Tools and Applications;• Radiation detection and Imaging in Medical Sciences and other fields of social interest. We thank all participants for the scientific presentation, for the interesting discussions arose after each presented talk, and we hope these interactions could trigger new and interesting project in this fascinating field.We thank all participants also for their effort to prepare good papers leaving a useful trace of this scientific event.We also thank the referees of the papers for their meticulous work and constructive suggestions.Last but not least, many thanks to the staff of the Accademia Peloritana dei Pericolanti for their assistance during the workshop, and the students of University of Messina for their active participation to scientific discussions.During the preparation of this volume, our young friend and colleague Antonio Anastasi sadly passed away after a long illness. Antonio has been a brilliant researcher and during the last period dedicated himself to the measurement of muon magnetic anomaly with unusual passion and enterprise. But first of all Antonio has been an exceptional boy, always positive, deeply helpful end friendly in respect of everyone. We wish to dedicate this volume in lovely memory of Doctor Antonio Anastasi.The Editors of the DeSyT2019 Proceedings:Antonio Trifiró (University of Messina and INFN Sec. Catania) Giuseppe Mandaglio (University of Messina and INFN Sec. Catania) Marina Trimarchi (University of Messina and INFN Sec. Catania)Messina, 20th of April 2020List of Photos are available in this pdf.

Monte Carlo simulations and n-p differential scattering data measured with Proton Recoil Telescopes

The neutron-induced fission cross section of 235U, a standard at thermal energy and between 0.15 MeV and 200 MeV, plays a crucial role in nuclear technology applications. The long-standing need of improving cross section data above 20 MeV and the lack of experimental data above 200 MeV motivated a new experimental campaign at the n_TOF facility at CERN. The measurement has been performed in 2018 at the experimental area 1 (EAR1), located at 185 m from the neutron-producing target (the experiment is presented by A. Manna et al. in a contribution to this conference). The 235U(n,f) cross section from 20 MeV up to about 1 GeV has been measured relative to the 1H(n,n)1H reaction, which is considered the primary reference in this energy region. The neutron flux impinging on the 235U sample (a key quantity for determining the fission events) has been obtained by detecting recoil protons originating from n-p scattering in a C2H4 sample. Two Proton Recoil Telescopes (PRT), consisting of several layers of solid-state detectors and fast plastic scintillators, have been located at proton scattering angles of 25.07° and 20.32°, out of the neutron beam. The PRTs exploit the ΔE-E technique for particle identification, a basic requirement for the rejection of charged particles from neutron-induced reactions in carbon. Extensive Monte Carlo simulations were performed to characterize proton transport through the different slabs of silicon and scintillation detectors, to optimize the experimental set-up and to deduce the efficiency of the whole PRT detector. In this work we compare measured data collected with the PRTs with a full Monte Carlo simulation based on the Geant-4 toolkit.

Large-area Si(Li) detectors for X-ray spectrometry and particle tracking in the GAPS experiment

The first lithium-drifted silicon (Si(Li)) detectors to satisfy the unique geometric, performance, and cost requirements of the General Antiparticle Spectrometer (GAPS) experiment have been produced by Shimadzu Corporation. The GAPS Si(Li) detectors will form the first large-area, relatively high-temperature Si(Li) detector system with sensitivity to X-rays to operate at high altitude. These 10 cm-diameter, 2.5 mm-thick, 4- or 8-strip detectors provide the active area, X-ray absorption efficiency, energy resolution, and particle tracking capability necessary for the GAPS exotic-atom particle identification technique. In this paper, the detector performance is validated on the bases of X-ray energy resolution and reconstruction of cosmic minimum ionizing particle (MIP) signals. We use the established noise model for semiconductor detectors to distinguish sources of noise due to the detector from those due to signal processing electronics. We demonstrate that detectors with either 4 strips or 8 strips can provide the required ≲4 keV (FWHM) X-ray energy resolution at flight temperatures of −35 to −45̂C, given the proper choice of signal processing electronics. Approximately 1000 8-strip detectors will be used for the first GAPS Antarctic balloon flight, scheduled for late 2021.

Particle identification methods other than RICH

Abstract This review presents a selection of examples of particle identification (PID) techniques alternative to RICH. State-of-the-art detectors are illustrated by means of the ALICE experiment at the LHC, where all PID techniques are implemented. Recent R&D efforts for particle detectors are largely driven by timing requirements imposed by the increasing collision rates of the HL-LHC and of future colliders. Some new developments will be discussed pointing out the most innovative aspects and preliminary performance results.

Particle-identification techniques and performance at LHCb in Run 2

One of the most challenging data analysis tasks of modern High Energy Physics experiments is the identification of particles. In this proceedings we review the new approaches used for particle identification at the LHCb experiment. Machine-Learning based techniques are used to identify the species of charged and neutral particles using several observables obtained by the LHCb sub-detectors. We show the performances of various solutions based on Neural Network and Boosted Decision Tree models. • Advanced machine learning techniques allow to increase particle identification performance both for charged and neutral particles. • Combining information from the LHCb subdetectors allows to achieve high background rejection for charged particle identification. • Using machine learning approaches to analyse the raw energy deposits in the calorimeter provides good prospects for high quality neutral particle identification.

CsI–Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE/E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

Development of TORCH readout electronics for customised MCPs

The TORCH detector is being developed for low-momentum particle identification, combining time-of-flight and Cherenkov techniques to achieve charged particle pi/K/p separation up to 10 GeV/c over a flight distance of 10m. This requires a timing resolution of 70 ps for single photons. Based on an existing scalable design, production and testing of a TORCH readout system has been undertaken over the past year, and a novel customized Micro Channel Plate (MCP) photomultiplier device with 128-channels has been instrumented. This paper will report on the development of the readout system which is being used to measure time-of-flight in a test-beam, and its performance. We will also discuss the communication and data alignment between the TORCH system and the TimePix3 telescope in order to provide track reconstruction.

Perspectives of the ALICE Experiment and Detector Upgrade

The goal of ALICE at the CERN-LHC is to study the structure of the QCD phase diagram at extremely high temperature and very large energy density. In particular, ALICE focuses on the properties of the hot and dense matter created in ultra-relativistic heavy ion collisions. The ALICE experiment features tracking to low transverse momentum (down to 150 MeV/c), as well as a variety of particle identification techniques, and jet identification. After the LS2 (2018-19 Long Shutdown), ALICE will focus on rare probes, such as heavy-flavors, quarkonia, photons and jets with improved performance, thanks to the detector upgrade which will further strengthen the physics potential of the experiment. In order to carry out the precision measurements of rare and untriggerable probes, the long-term strategy of the ALICE upgrade is to fully utilize high luminosity provided by the LHC after the LS2, and to collect 10 nb−1 at the collision rates of 50 kHz (luminosity L = 6 × 1027cm−2s−2). In this talk, we present the current status of the ALICE detector, the limitations of existing measures and the prospects for physical measurements with the upgrade.

Use of cluster counting technique for particle identification in a drift chamber with the cathode strip readout

The possibility of using the clusters counting technique for particle identification in a drift chamber with the cathode strip readout is experimentally investigated. Results of counting of primary ionization clusters on a relativistic particle track, as well as results of computer simulation of pion, kaon, and proton identification in the momentum range of 1–8 GeV/c, are presented.

Identified light-flavour particle production measured with ALICE at the LHC as a probe of soft QCD and hot hadronic matter

ALICE is a general-purpose heavy-ion experiment able to identify particles over a wide momentum range thanks to excellent vertexing and tracking performance, low material budget and different Particle IDentification (PID) techniques. In this paper the measurement of the production of identified light flavour particles in pp, p-Pb and Pb-Pb collisions is reported. It is of fundamental importance to study the particle production mechanisms playing a role in the different momentum ranges and probe the hot medium formed in heavy-ion collisions. Information on the effects of the medium produced in Pb-Pb collisions on particle production can be obtained comparing the particle ratios in pp and Pb-Pb events and studying the nuclear modification factor (RAA). The transverse momentum (pT) integrated yields and ratios are then discussed in terms of thermal models to extract the properties of the medium produced in Pb-Pb collisions at the chemical freeze-out.