Particle Identification Techniques Research Articles

Cascade training technique for particle identification

The cascade training technique which was developed during our work on the MiniBooNE particle identification has been found to be a very efficient way to improve the selection performance, especially when very low background contamination levels are desired. The detailed description of this technique is presented here based on the MiniBooNE detector Monte Carlo simulations, using both artificial neural networks and boosted decision trees as examples.

The alpha magnetic spectrometer on the International Space Station

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to measure charged cosmic ray spectra up to the TV region, with high-energy photon detection capability up to few hundred GeV. AMS is a superconducting spectrometer with large acceptance, long duration (at least three years for the magnet) and state of the art particle identification techniques. AMS will investigate the composition of cosmic rays with high statistics and provide the most sensitive search for the existence of antimatter nuclei and for the nature of dark matter. The detector is being constructed with an eight-layer Silicon Tracker inside a large superconducting magnet, providing a ~0.8 Tm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2 </sup> bending power and an acceptance of ~0.4 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> sr. A Transition Radiation Detector and a three-dimensional Electromagnetic Calorimeter allow for electron, positron and photon identification, while a Time of Flight scintillating system and a Ring Image Cerenkov detector perform independent velocity measurements. This complex apparatus will identify and measure nuclei up to Iron. We will describe the overall detector construction and performance, which is due to be completed by 2006. The detector will be installed on ISS (International Space Station) in 2008

AMS: A Cosmic Ray Observatory

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to operate in space beyond the earth atmosphere. AMS will measure all the charged cosmic rays and light nuclei spectra in the GV to TV rigidity domain, and high energy cosmic gamma rays as well. With a large acceptance, at least 3 years of observation, and state of the art redundant particle identification techniques, AMS will provide a continuous survey of charged cosmic rays fluxes and the most sensitive search for the existence of anti matter nuclei and for the origin of dark matter. The detector construction will be completed by 2005. AMS should be installed on the ISS (International Space Station) in 2007 and will record several billions cosmic rays per year of operation.

AMS—Alpha Magnetic Spectrometer on the International Space Station

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to measure charged cosmic ray spectra up to the TeV region, with high-energy photon detection capability up to a few hundred GeV. After the successful precursor flight on STS-91 in 1998 the detector was redesigned (AMS-02) to operate for 3 years on the International Space Station (ISS). With its large acceptance, the long flight duration and its state-of-the-art particle identification techniques, AMS-02 will increase substantially the sensitivity on antimatter and dark matter searches. In addition, AMS-02 will provide measurements of cosmic ray fluxes with unprecedentedly large statistics and over a wide kinematic range.

AMS—Alpha Magnetic Spectrometer on the International Space Station

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to measure charged cosmic ray spectra up to the TeV region, with high-energy photon detection capability up to a few hundred GeV. After the successful precursor flight on STS-91 in 1998 the detector was redesigned (AMS-02) to operate for 3 years on the International Space Station (ISS). With its large acceptance, the long flight duration and its state-of-the-art particle identification techniques, AMS-02 will increase substantially the sensitivity on antimatter and dark matter searches. In addition, AMS-02 will provide measurements of cosmic ray fluxes with unprecedentedly large statistics and over a wide kinematic range.

The HERMES dual-radiator RICH detector

Abstract The HERMES experiment emphasizes measurements of semi-inclusive deep-inelastic scattering. Most of the hadrons produced lie between 2 and 10 GeV , a region in which it had not previously been feasible to separate pions, kaons, and protons with standard particle identification (PID) techniques. The recent development of new clear, large, homogeneous and hydrophobic silica aerogel material with a low index of refraction offered the means to apply RICH PID techniques to this difficult momentum region. The HERMES instrument uses two radiators, C 4 F 10 , a heavy fluorocarbon gas, and a wall of silica aerogel tiles. A lightweight spherical mirror constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality provides optical focusing on a photon detector consisting of 1934 photomultiplier tubes (PMT) for each detector half. The PMT array is held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet. Ring reconstruction is accomplished with pattern recognition techniques based on a combination of inverse and direct ray tracing.

Advances in RICH particle identification

The Ring Imaging Cherenkov (RICH) technique for particle identification has undergone considerable development since it was first proposed more than 20 years ago. The present report focuses on deve ...

Particle identification using the DELPHI RICH detectors

A Cherenkov ring reconstruction algorithm has been developed to determine the mean Cherenkov angle. It is used to study the response of the DELPHI RICH detectors and to identify particles. Results from the analysis of real and simulated data samples are presented. Finally, two different techniques for particle identification and their applications to physics analyses are described.

HIRICH, a novel device for velocity measurement of relativistic ions

A novel technique for particle identification of relativistic heavy ions has been developed utilizing a Heavy-Ion Ring Imaging Cherenkov detector (HIRICH) for velocity measurement. The HIRICH is characterized by a thin liquid or solid state radiator, a proximity focusing geometry and a fast gaseous photon detector with CsI photon converter. A velocity resolution of Δ β/ β=8×10 −4 (fwhm) has been measured for Ru 44+ particles of β≃0.85. The detector design and the performance in heavy-ion reaction studies at the GSI-Darmstadt are presented.

The Nearest-Neighbor Technique for particle identification

In this paper we propose the Nearest-Neighbor Technique (NNT), a classical nonparametric method of Pattern Recognition, for addressing Particle Identification (PID) problems. Given a set of correctly identified events and a distance measure between events, the NNT assigns a previously unseen event the same class of the nearest event in the set. The NNT can be applied to correlated data with virtually no preprocessing and does not require assumptions on the shape of the various probability distributions. We compare the performance of NNT on electron identification in experiment E760 at FNAL against a standard likelihood technique, and find that NNT gives better results, particularly in the rejection rates. We conclude that NNT, which is conceptually clear and easy to implement and use, can be very useful for PID.

Automatic wear particle classification using neural networks

Although the study of wear debris can yield much information on the wear processes operating in machinery, the method has not been widely applied in industry. The main reason is that the technique is currently time consuming and costly due to the lack of automatic wear particle analysis and identification techniques. In this paper, six common types of metallic wear particles have been investigated by studying three‐dimensional images obtained from laser scanning confocal microscopy. Using selected numerical parameters, which can characterise boundary morphology and surface topology of the wear particles, two neural network systems, i.e., a fuzzy Kohonen neural network and a multi‐layer perceptron with backpropagation learning rule, have been trained to classify the wear particles. The study has shown that neural networks have the potential for dealing with classification tasks and can perform wear‐particle classification satisfactorily.

An approach to nuclear charge identification with CR-39 polymeric nuclear track detector

The etch-rate ratio V of CR-39 (DOP) nuclear track detector as a function of residual range R for 1 ≤ Z ≤ 26 nuclei have been determined. On the base of the sensitivity function V( R), an attempt has been made to study the possibility of particle identification technique in CR-39 by plotting the calculated etched-track cone length versus the starting range for various ions in the range 0.1 < E A ≤ 140 MeV/u . A correlation has been established between the nuclear charge and the etched-track parameters. The present calculation shows the possibility of identifying the charge of a nuclear particle with appreciable charge resolution.

Progress in [formula omitted] techniques used for particle identification

Particle identification techniques by measuring the specific energy loss dE dx have been widely used in high energy physics experiments for many years. The basics of the energy loss measurements are described briefly. The stability requirements, corrections and, in particular, the non-linear saturation effect are discussed in more detail. The performance of present large detectors such as resolution and particle separation power in the relativistic rise region are reviewed. Typical applications to various physics analyses at LEP are given.

Pile-up suppression in backscattering spectrometry using particle identification technique

The extra information provided due to the detection of a single event by two detectors is used to eliminate the pile-up background in the conventional backscattering spectra. The simultaneous measurement of the registered particle specific energy loses along with its total energy enables to distinguish the pile-up signals which do not meet the requirements derived from Bethe-Bloch formula. The particle identification technique with on-line operating mathematic processor was used to select undistorted signals. The demonstrative experiment has been performed to show the practically complete elimination of the pile-up background in the wide energy region of the backscattering spectrum.

Particle identification by measurement of track cone length as a function of the residual range of heavy ions in CR-39 and Lexan polycarbonate

The maximum etchable ranges of heavy ions such as 238U, 208Pb, 197Au, 132Xe and 93Nb in CR-39 and 238U, 197Au and 132Xe in Lexan polycarbonate have been determined. An attempt has been made to examine the suitability of the single-sheet particle identification technique in CR-39 and Lexan polycarbonate by plotting track cone length vs residual range for different heavy ions. A comparison has been made between experimental and theoretical values of ranges of different heavy ions in these detectors. A reasonably good agreement has been observed between the experimental and the theoretically computed values.

Particle identification via Cherenkov correlated timing

We describe a new particle-identification technique based on precision timing measurements to determine the Cherenkov angle of photons emitted by particles passing through a quartz radiator. A Monte Carlo simulation indicates that good π-K separation can be obtained for a large range of particle momenta and incident angles. A prototype detector to demonstrate the feasibility of the concept is under construction.

A modular solid state detector for measuring high energy heavy ion fragmentation near the beam axis

A multi-element solid state detector has been designed to measure fluences of fragments produced near the beam axis by high energy heavy ion beams in thick targets. The detector is compact and modular, so as to be readily reconfigured according to the range of fragment charges and energies to be measured. Preamplifier gain settings and detector calibrations are adjustable remotely under computer control. We describe the central detector, its associated detectors and electronics, triggering scheme, data acquisition and particle identification techniques, illustrated by data taken with 600 MeV/u 56Fe beams and thick polyethylene targets at the LBL Bevalac. The applications of this work to space radiation protection are discussed.

The Particle Atlas Electronic Edition

Abstract In his preface to the first edition of The Particle Atlas, Jim Lodge talks of the challenge he posed to Dr. Walter McCrone in the 1950s to come up with a taxonomy for particles to assist in the identification of particles under the microscope. Jim's interest and the support of the Midwest Air Pollution Prevention Association and, laier, the US Public Health Service, gave birth to the first edition of The Particle Ailas. This first edition, published in 1967, was a single volume which combined guidance on particle separation and identification techniques with a collection of optical micrographs of reference particles. The demand for this reference work soon outpaced the supply. In the meantime, however, it had become obvious that reprinting was not the answer as increased application of the microscope, in all its implementations, to environmental pollution and industrial contamination had resulted in a need for a more comprehensive work.

Modern Microscopy on The Light Side: An Instrumental Approach to Small Particle Identification

Abstract Developments in space exploration, microelectronics, and other high-tech industries have promoted cleanroom technology and increased the need to identify particles sometimes too small to handle with the polarizing light microscope. Light microscopy has traditionally been the most commonly used technique for small particle identification and many microscopists are very proficient in identifying particles using a polarizing light microscope as the principal investigative tool. The polarizing light microscope, in the hands of a good microscopist, is an extremely efficient instrument for particles down to a few micrometers in size. However, in the size range below 5 pm, an instrumental approach to small particle identification is essential. The development of electron microbeam instruments in the early '60s and 70s introduced a new dimension to small particle identification. In these instruments, particles of 1 urn and smaller can be chemically identified when chemical characterization of particles is combined with cathodoluminesence and a relatively simple optical characterization in the instrument itself.

P, d and α particle discrimination in NRA: thin, adjustable sensitive zone semiconductor detectors revisited

Overlapping peaks arising from particles of different types in complex NRA energy spectra may be unscrambled by using partially depleted semiconductor detectors with well chosen sensitive zone thicknesses. The latter should range from ∼ 30 to ∼ 100 μm for removing proton or deuteron peaks from a typical alpha particle energy interval between 1.5 and 12 MeV. It is difficult to find commercial detectors with such characteristics as they are usually made from silicon of too high a resistivity. Special, large area detectors prepared in nominal 500 Ωcm silicon were investigated for their response, both in energy equivalent amplitude and spread, to protons, deuterons and alpha particles as a function of their energy and of the applied bias voltage. The results may be interpreted in terms of charge collection efficiency depth profiles extending behind the depletion region. If turns out that the effective sensitive thickness of such detectors may be varied continuously over a wide range so that it may be tuned, in combination with a well chosen Mylar absorber, to the optimal value required for unscrambling a large variety of complex spectra, arising from deuteron or 3He beam induced reactions. The results suggest that it is possible and desirable to produce detectors with well defined discrimination characteristics. The advantages of this simple method with respect to dE dx telescope based particle identification techniques are discussed. Various applications to the NRA of light isotopes are presented.