Particle Detection Efficiency Research Articles

Beta particle detection efficiency of the radiation sensor made from a mixture of polyaniline and titanium oxide

We developed a new real-time radiation sensor using an organic semiconductor and measured its β-particle detection sensitivity. This sensor is fabricated by simply combining a p-type semiconductor, polyaniline (Pani), with an n-type semiconductor, TiO2, and processing the compound. Since Pani and TiO2 are both inexpensive materials, the sensor can be fabricated at a lower cost than inorganic semiconductor sensors. The signal of each fabricated sensor was measured by a charge sensitive ADC for the irradiation of β-particles. The response signal data of the ADC for each irradiation was measured to calculate the detection efficiency of the detector. The maximum detection efficiency measured as β-particle sensitivity of the sensor was 1%. This β-particle sensitivity is higher than that reported of Pani sensors in the past.

Enhancement of ARROW Photonic Device Performance via Thermal Annealing of PECVD-based SiO2 Waveguides.

Silicon-based optofluidic devices are very attractive for applications in biophotonics and chemical sensing. Understanding and controlling the properties of their dielectric waveguides is critical for the performance of these chips. We report that thermal annealing of PECVD-grown silicon dioxide (SiO2) ridge waveguides results in considerable improvements to optical transmission and particle detection. There are two fundamental changes that yield higher optical transmission: (1) propagation loss in solid-core waveguides is reduced by over 70%, and (2) coupling efficiencies between solid- and liquid-core waveguides are optimized. The combined effects result in improved optical chip transmission by a factor of 100-1000 times. These improvements are shown to arise from the elimination of a high-index layer at the surface of the SiO2 caused by water absorption into the porous oxide. The effects of this layer on optical transmission and mode confinement are shown to be reversible by alternating subjection of waveguides to water and subsequent low temperature annealing. Finally, we show that annealing improves detection of fluorescent analytes in optofluidic chips with a signal-to-noise ratio improvement of 166x and a particle detection efficiency improvement of 94%.

Large-size triple GEM detectors for the CMS forward muon upgrade

The CMS collaboration considers upgrading the muon forward region which is particularly affected by the high-luminosity conditions at the LHC. The proposal involves Gas Electron Multiplier (GEM) chambers, which are able to handle the extreme particle rates expected in this region along with a high spatial resolution. This allows to combine tracking and triggering capabilities, which will improve the CMS muon High Level Trigger, the muon identification and the track reconstruction. Intense R&D has lead to the development of several GEM prototypes and associated detector electronics which were operated in several test beams. Strip cluster parameters, detection efficiency, and spatial resolution for charged particles are studied with position and high voltage scans and at different inclination angles. A first GEM station is foreseen to be already installed in LHC Phase-I to operate jointly together with the existing CSC detectors in the forward region. The resulting improved transverse momentum assignment and lower trigger fake rate will reduce the needed bandwidth and therefore allow to lower the trigger threshold resulting in an increased sensitivity in channels triggering on soft muons, such as H to tau's with subsequent leptonic decays to muons. Further GEM detectors are proposed for LHC Phase-II to significantly increase the forward muon acceptance.

Dependence of CPC cut-off diameter on particle morphology and other factors

ABSTRACTIn this investigation, we summarize performance parameters of 24 TSI CPCs model 3772 and 9 TSI CPCs model 3790 determined at the World Calibration Aerosol Centre Physics hosted by the Leibniz Institute for Tropospheric Research. Model 3790 CPCs are basically identical to model 3772 laminar continuous flow type butanol-based CPCs with a modified temperature difference between saturator and condenser. The average 50% detection efficiency for silver particles for 3772 and 3790 instruments was found to be 7.52 ± 0.04 nm and 24.34 ± 0.29 nm (average mobility diameter ± standard deviation), respectively. Small changes of the temperature difference between saturator and condenser cause larger shifts of the 50% detection efficiencies of 3790 CPCs compared to 3772 CPCs. In addition to the known calibration material dependence of the 50% detection efficiencies of 3790 CPCs, we found a dependence on the morphology of the particles used for calibration. In our experiments more spherical particles shifted the ...

Development of new-type nuclear emulsion for a balloon-borne emulsion gamma-ray telescope experiment

This study reports a new-type of nuclear emulsion that improves the track-finding efficiency of charged particle detection. The emulsion is applied to the GRAINE project, a balloon-borne experiment that observes cosmic γ-rays through an emulsion γ-ray telescope. The new emulsion film dramatically improves the detection efficiency for γ-rays. The nuclear emulsion gel and films for the second GRAINE balloon-borne experiment (GRAINE-2015) were fully self-produced by ourselves. New handling methods for the novel emulsion film have also been developed. Over time, the stored films gradually become desensitized to minimum ionizing particles, but the original sensitivity can be restored by a resetting process. Moreover, the fading of latent images can be arrested by a drying process. To sensitize the new-type films and avoid their fading, emulsion preprocessing was applied immediately prior to GRAINE-2015. A balloon flight with the emulsion γ-ray telescope was successfully completed in Australia on 12th May 2015. By scanning with automated optical microscopes and analyzing the penetrated tracks, we confirmed the high track-finding efficiency (97%) of the mounted films. The analysis of γ-ray event detection, aims at detecting Vela pulsar, is in progress.

Operation and performance of the ASHIPH counters at the KEDR detector

In 2014 the fully installed ASHIPH (Aerogel, SHifter, PHotomultiplier) system began its operation in the KEDR experiment at the VEPP-4M e+e−-collider. The system contains 1000liters of aerogel with refractive index n=1.05 in 160 counters that are arranged in two layers. Cherenkov light collection is preformed by means of wavelength shifters (WLS). 160Micro-Channel Plate (MCP) PMTs with multialkali photocathode are used as photodetectors. Efficiency of relativistic particles detection was measured with e+e−→e+e− events and cosmic muons. Detection efficiency for under-threshold particles was measured with cosmic muons. From these data π/K-separation of 4σ at the momentum 1.2GeV/c was obtained.

An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments.

A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring. We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency.

Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection.In this paper, the detector structure, as well as the detector’s measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5MeV) is ~63%. The measured detection efficiency for beta particles is ~89% for 90Sr–90Y (average energy of 195.8keV, 934.8keV), ~50% for 36Cl (average energy of 251.3keV), and 35% for 137Cs (average energy of 156.8keV).

The iQID camera: An ionizing-radiation quantum imaging detector

We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detector׳s response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The confirmed response to this broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated by particle interactions is optically amplified by the intensifier and then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. The spatial location and energy of individual particles are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, excellent detection efficiency for charged particles, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discriminate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is real-time, single-particle digital autoradiography. We present the latest results and discuss potential applications.

GEM based R&D for muon chambers of CBM experiment at FAIR

A Gas Electron Multiplier (GEM) based detector system has been envisaged for use in a muon tracker in the CBM experiment at FAIR. The choice of the detector technology is mainly guided by the stringent requirements of rate capability and radiation tolerance in the harsh CBM environment, where the particle rates reach upto about 1 MHz/cm2. Several 10 cm × 10 cm triple GEM prototypes have been built at VECC and tested with radioactive sources and with proton and pion/muon beams. Owing to high rate requirements, all the detectors in CBM will have to be operated in a self triggered mode of readout. The readout electronics also have to be appropriately tuned to cater to high rates. A detailed investigation of the self triggered readout electronics including its appropriate setting parameters have been carried out. Prototype tests based on self triggered mode of readout showed a charged particle detection efficiency of more than 90%. The Muon detector modules would employ large area GEM foils. First attempts to stretch and frame large area GEMs, foils of 31 cm × 31 cm have been carried out locally using thermal techniques. A relative gain variation of less than 10% has been observed.

Computer simulation of charged fusion-product trajectories and detection efficiency expected for future experiments within the COMPASS tokamak

This paper presents results of computer simulations of charged particle motions and detection efficiencies for an ion-pinhole camera of a new diagnostic system to be used in future COMPASS tokamak experiments. A probe equipped with a nuclear track detector can deliver information about charged products of fusion reactions. The calculations were performed with a so-called Gourdon code, based on a single-particle model and toroidal symmetry. There were computed trajectories of fast ions (> 500 keV) in medium-dense plasma (ne < 1014 cm−3) and an expected detection efficiency (a ratio of the number of detected particles to that of particles emitted from plasma). The simulations showed that charged fusion products can reach the new diagnostic probe, and the expected detection efficiency can reach 2 × 10−8. Based on such calculations, one can determine the optimal position and orientation of the probe. The obtained results are of importance for the interpretation of fusion-product images to be recorded in future COMPASS experiments.

A coordinate muon chamber based on thin-walled drift tubes

The design and manufacturing technology of a prototype coordinate detector module with dimensions of 2.0 × 0.5 m2 on the basis of 2-m-long drift straw tubes are described. The selected design and technology allow large-area detectors to be constructed from these modules. Results of the module testing at gas pressures of 1–4 bar are described. The characteristic features of the module are a small radiation thickness, a high radiation hardness, a high detection efficiency for charged particles, as well as the feasibility of its high granularity (using small-diameter straw tubes and segmentation along the tube length). The possibility of optimizing the operating conditions of the module over a wide range of the working gas pressure is shown.

A quantitative study of the 6NM-64 neutron monitor by using Geant4: 1. Detection efficiency for different particles

The neutron monitors are the ground based detectors that continuously measure the flow of the cosmic rays that reach the earth′s surface. The measurements of the neutron monitors are of great importance for the scientific community since they contribute to the study of several scientific fields, such as the solar activity and the prediction of the space weather. For this reason, most of the neutron monitors worldwide are organized in a network, in order for their measurements to be easily accessible. The correct evaluation of the measurements and their connection with the physical quantities of the cosmic rays require the knowledge of the interactions and the detection procedure that take place inside the neutron monitor. In this work a quantitative study of the 6NM-64 behavior is presented based on Monte Carlo simulations by using the well known Geant4 simulations toolkit. The study focuses on the detection efficiency of the neutron monitor, both in sections and as a whole for the different particle species, on its dependence on the incident direction of the particles and on the secondary neutrons produced inside the neutron monitor.

A charged particle detector array for detection of light charged particles from nuclear reactions

A 4π charged particle detector array (CPDA), for detecting low-Z charged particles from nuclear reactions, was built to improve selection of fusion evaporation channels for in-beam gamma spectroscopy measurements at Inter University Accelerator Centre, New Delhi. The array consists of fourteen fast–slow plastic phoswich detectors coupled to photomultiplier tubes through indigenously developed optical light guides. This paper describes design of optical light guide, target chamber, front-end electronics and presents in-beam performance of the array. Custom made analogue electronic device enables online selection of nuclear reaction channel. The charged particle detection efficiency and improvement in peak to background ratio obtained using CPDA in conjunction with a gamma-detector array demonstrates its usefulness in selection of specific nuclear reaction channel. This array has been used in a number of nuclear spectroscopic and reaction investigations.

Charged particle detection performances of CMOS pixel sensors produced in a [formula omitted] process with a high resistivity epitaxial layer

The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18 during the second long shutdown of the LHC (LS2). A major motivation for this upgrade is to extend the physics reach for charmed and beauty particles down to low transverse momenta. This requires a substantial improvement of the spatial resolution and the data rate capability of the ALICE Inner Tracking System (ITS). To achieve this goal, the new ITS will be equipped with 50μm thin CMOS Pixel Sensors (CPS) covering either the three innermost layers or all the 7 layers of the detector. The CPS being developed for the ITS upgrade at IPHC (Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at RHIC in a 0.35μm CMOS process. In order to satisfy the ITS upgrade requirements in terms of readout speed and radiation tolerance, a CMOS process with a reduced feature size and a high resistivity epitaxial layer should be exploited. In this respect, the charged particle detection performance and radiation hardness of the TowerJazz0.18μm CMOS process were studied with the help of the first prototype chip MIMOSA 32. The beam tests performed with negative pions of 120GeV/c at the CERN-SPS allowed to measure a signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22 and 32 depending on the pixel design. The chip irradiated with the combined dose of 1MRad and 1013neq/cm2 was observed to yield an SNR ranging between 11 and 23 for coolant temperatures varying from 15°C to 30°C. These SNR values were measured to result in particle detection efficiencies above 99.5% and 98% before and after irradiation, respectively. These satisfactory results allow to validate the TowerJazz0.18μm CMOS process for the ALICE ITS upgrade.

A readout system for a cosmic ray telescope using Resistive Plate Chambers

Resistive Plate Chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes. They have good time resolution and with finely segmented readout can also give a spatial resolution of better than 1 mm. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a Muon Scattering Tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. We describe a readout system for fine-pitch RPCs using MAROC3 readout chips capable of scaling to a large system.

A novel technique to detect special nuclear material using cosmic rays

Abstract. Resistive plate chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes, due to their excellent time resolution, rate capability, and good spatial resolution. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a muon scattering tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. The required spatial granularity is achieved by using 330 readout strips per RPC with 1.5 mm pitch. The RPCs have shown an efficiency above 99% and an estimated intrinsic resolution below 1.1 mm. Due to these qualities, RPCs serve as excellent candidates for usage in volcano radiography.

Development of Variable Flow Rate Isokinetic Sampling System for 0.5–15-μm Aerodynamic Diameter Particles

Isokinetic sampling is required when evaluating the aerodynamic sizes of particles released from dry powder inhalers (DPI) under simulated breathing condition since anisokinetic sampling may lead to significant sampling error for coarse particles. We propose an isokinetic measuring system for aerosol particles from a stream in a narrow conduit of variable flow rates (variable flow rate aerosol sampler, VFAS) combined with Aerodynamic Particle sizer® APSTM spectrometer (model 3321, TSI Inc.). The VFAS was capable of generating variable sampling flow rates by adjusting the flow resistance of makeup air to produce constant flow rate of aerosol to the APS. The penetrations through the VFAS-APS system were measured using monodisperse particles with a size range of 0.7–15 μm by applying a rectangular flow rate–time pattern of sampling air, and we found that the VFAS-APS system can measure the number concentration of particles with the particle detection efficiency (particle penetration through the system) of al...

Demonstrating the of a CMOS pixel detector for a future neutron dosimeter

Abstract The RaMsEs group (Radioprotection et Mesures Environnementales) is working on a new compact device for operational neutron dosimetry. The electronic part of the detector is made of an integrated active pixel sensor, originally designed for tracking in particle physics. This device has useful features, including a high detection efficiency for charged particles, a good radiation resistance, a high readout speed and a low power consumption. Moreover, because of the thinness of the active layer, these CMOS sensors have low sensitivity to γ - rays , which is an attractive feature for neutron issues. In order to determine the γ response of the sensor, measurements have been carried out with a γ source of 60Co (1.17 MeV and 1.33 MeV). Other experiments have been performed with a fast neutron source of AmBe. We demonstrate the good discrimination between recoil protons from fast neutrons and from γ - background . Our results show that with an appropriate threshold, most γ - rays that generate photoelectrons can be removed from detection.

Evaluation of silicon active pixel sensors for alpha particle detection

Alpha particles can be used as a test stimulus offering several advantages for probing materials of micrometre thicknesses. In this work a silicon CMOS Active Pixel Sensor (APS) is evaluated for alpha particle detection and imaging. These devices can replace traditionally used solid-state track detectors, giving advantages of increased sensitivity, improved linearity and higher dynamic range. CMOS APSs offer high detection efficiency, low noise and digital readout. Qualitative and quantitative analysis of the back-illuminated back-thinned (BT) and standard sensor response to 5.5 MeV alpha particles is presented. Alpha particle detection efficiency was estimated and energy resolution was measured. Imaging capabilities were assessed and quantified. Cluster centroiding algorithms were implemented for image quality improvement.