Compact Particle Research Articles

Test beam studies for a highly granular GRPC Semi-Digital HCAL

The Particle Flow Analysis approach retained for the future ILC detectors requires high granularity and compact particle energy deposition. A Glass Resistive Plate Chamber based Semi-Digital calorimeter can offer both at a low price for the hadronic section. This paper presents some recent developments and results near test beam in the use of Glass Resistive Plate Chamber with embedded front-end electronics to build a prototype based on this principle. All the critical parameters such as the spatial and angular uniformity of the response as well as the noise level have been measured on small chambers and found to be appropriate. Small semi-conductive chambers allowing for high rates and a large chamber have also been tested.

Aerodynamic and Mobility Size Distribution Measurements to Reveal Biodiesel Effects on Diesel Exhaust Aerosol

This article examines the effect of biodiesel blends on the exhaust aerosol from a Euro 3 passenger car. Five different feedstock oils (soybean, palm, sunflower, rapeseed, and used frying oil) were used to produce fuels with 10% vol. content in biodiesel (B10). Use of the B10 blends led to a systematic reduction of PM mass emissions in the range of ∼9% (rapeseed) to 23% (used frying oil) on average. The combination of particle size distributions based on the aerodynamic and the mobility diameters led to the estimation of the fractal dimension (DF) for non-volatile particles. This was found to range from 2.52 for the baseline (fossil) fuel to 2.62 for the palm oil blend, suggesting that biodiesel can affect the particle morphology, even at this low blending ratio. The differences were statistically significant. The increase of the DF is translated to more compact particle structure, which in turn denotes lower specific surface area. The volatile fraction of PM lies within a range of 1–9% when fossil diesel...

Design and calibration of a neutral particle analyzer for the KSTAR

Detection of high energy particles is one of the critical issue at fusion plasmas. A single channel compact neutral particle analyzer based on small Si-diode detectors is developed to measure energetic hydrogen minority ions from ion cyclotron heating with energies between 50 and 300 keV. The diagnostic employs the integrated pre-amplifier, shaping amplifier and multi channel analyzer. The basic performance of the detector is checked by using gamma sources of Am-241 and Ba-133. In this paper, design feature and calibration results of a neutral particle analyzer are described.

XAS study of the reversible reactivity mechanism of micro- and nanostructured electrodeposited Cu2O thin films towards lithium

Highly uniform electrodeposited Cu2O electrodes for Li-ion batteries, with variable particle size, morphology and thickness, have been studied in the charged and discharged steps as a function of the number of cycling processes, by means of ex situ X-ray absorption spectroscopy (XAS) at the Cu K edge. Both, fingerprint analysis of the X-ray Absorption Near Edge Structure spectra (XANES) and the radial atomic distribution obtained by the analysis of the Extended X-ray Absorption Fine Structure (EXAFS) spectra, have allowed us to quantify the bimodal distribution (Cu and Cu2O) of the electrodes. These results correlate qualitatively well with their different electrochemical response, establishing a deep insight into the reversible reactivity mechanism of these films towards lithium in Li batteries. Our results demonstrate that the reversibility of the reduction process upon the number of cycles depends on the thickness, as it was suggested in previous works but also on the morphology of the electrodes. Higher reversibility corresponds to smaller thickness electrodes. For similar thickness, the reversibility is higher for porous and nanometric particle electrodes than for compact and micrometric particle electrodes. The thinnest film exhibited an increase of capacity after several recycling steps, which agrees with the increase of the Cu2O content.

Numerical Simulation of the Shock Compaction of W/Cu Powders

A numerical simulation approach is used to study the deformation and temperature distribution of W/Cu powders under shock compaction. A two-dimensional micromechanical model is employed where only a few particles are considered. The simulation is performed using plane strain element and Lagrange formulation. Shock compaction is achieved by bringing in the W/Cu powders an intense compression wave using a high-velocity rigid wall. The effects of compact velocity, particle size and friction on the particle deformation and temperature distribution are discussed based on the results of simulations. The study provides a detailed understanding of the micromechanical behavior of metal powders during shock compaction process.

FRACTAL-SHAPED COMPLEMENTARY ELECTRIC-LC RESONATOR FOR BANDSTOP FILTER

An equivalent circuit model for single negative metama- terial (MTM) transmission line based on microstrip complementary electric inductive-capacitive resonator (CELC) is proposed for the flrst time. The verifled circuit model gives strong support to the interpreta- tion of all exhibited electromagnetic (EM) phenomena. The nonpure magnetic and electric resonances have been demonstrated by consti- tutive EM parameters. Based on the conclusions that have drawn, a more compact sub-wavelength particle based on Hilbert-shaped CELC (H-CELC) is proposed. The design procedures of the H-CELC-loaded MTM cell are derived based on the circuit model. For application, a bandstop fllter covering one of the ISM bands 5.2GHz by cascading two H-CELC cells is designed, fabricated and measured. Consistent results between simulation and measurement have conflrmed the de- sign. The established theory based on the proposed circuit model is of reference value for the design of novel bandstop devices.

An integrated fiber-based optical trap for single airborne particles

We present a compact fiber-based optical airborne particle trap that is integrated on a microscope slide. Light guided in a short glass capillary is used to inject micron-sized droplets into an optical trap formed by the same light and a counterpropagating beam emanating from a single-mode optical fiber. The glass capillary ensures separation of trapped particles from remaining aerosol in the injection chamber. Permanent alignment of the fibers and the capillary allows for adjustment-free operation. Mie resonances arising in the radiation pressure exerted on trapped droplets are detected via a position stabilization feedback loop and are used to precisely determine the size evolution of trapped glycerol–water droplets.

New micro-cones targets can efficiently produce higher energy and lower divergence particle beams

AbstractSmall conical targets have been used in high intensity laser target interaction mostly in the context of fast ignition. We demonstrate that when cone targets are shaped appropriately and used with specific interaction conditions, they can produce particle beams of higher maximum energy and number in a lower angular divergence than flat targets. This is relevant to fast ignition, small compact particle beams, medical applications, focused ion and/or electron beam microscopes. This fact carries the potential to produce particle beams that are no longer limited by the characteristics of the laser. Note that for fast ignition, reducing the divergence of the beam lowers the energy requirement and enhances the energy deposition into the compressed fuel.

Estimation of particle swarm distribution algorithms: Combining the benefits of PSO and EDAs

This paper presents a novel framework of the estimation of particle swarm distribution algorithms (EPSDAs). The aim is to effectively combine particle swarm optimization (PSO) with the estimation of distribution algorithms (EDAs) without losing their unique features. This aim is achieved by incorporating the following mechanisms: (1) selection is applied to the local best solutions in order to obtain more promising individuals for model building, (2) a probabilistic model of the problem is built from the selected solutions, and (3) new individuals are generated by a stochastic combination of the EDA’s model sampling method and the PSO’s particle moving mechanism. To exhibit the utility of the EPSDA framework, an extended compact particle swarm optimization (EcPSO) is developed by combining the strengths of the extended compact genetic algorithm (EcGA) with binary PSO (BPSO), along the lines of the suggested framework. Due to its effective nature of harmonizing the global search of EcGA with the local search of BPSO, EcPSO is able to discover the optimal solution in a fast and reliable manner. Experimental results on artificial to real-world problems have adduced grounds for the effectiveness of the proposed approach.

Active quadrupole stabilization for future linear particle colliders

The future Compact LInear particle Collider (CLIC) under study at CERN will require to stabilize heavy electromagnets, and also to provide them some positioning capabilities. Firstly, this paper presents the concept adopted to address both requirements. Secondly, the control strategy adopted for the stabilization is studied numerically, showing that the quadrupole can be stabilized in both lateral and vertical direction. Finally, the strategy is validated experimentally on a single degree of freedom scaled test bench.

Membrane Fouling Control of Hybrid Membrane Bioreactor: Effect of Extracellular Polymeric Substances

A hybrid membrane bioreactor (HMBR) was developed by adding biofilm carriers into a conventional membrane bioreactor (CMBR), and a study was conducted on the characteristics of the activated sludge in the HMBR and CMBR with attention paid to the effect of extracellular polymeric substances (EPS) on membrane fouling. As a result, lower EPS concentrations were detected from the HMBR than the CMBR, bringing about a substantial improvement in the sludge properties. The larger particle size, more compact particle structure, and better settleability of the sludge in the HMBR resulted in lower cake layer resistance and much slower TMP increase.

Quasi-static simulations of compact polydisperse particle systems

The Discrete Element Method (DEM) was originally devised by Cundall and Strack (1979), as a technique to examine the micromechanics of granular media with the anticipation that this would lead to more physically reliable continuum theories to describe the quasi-static deformation of granular material such as sand. However, the methodology models the evolution of a system of particles as a dynamic process. Consequently there have been numerous publications of the application of DEM to an increasingly wider variety of problems in many areas of engineering and science. This paper, however, focuses on the original motivation for DEM and attempts to provide a state-of-the-art understanding of the quasi-static deformation of granular media.

Pattern formation in two-dimensional square-shoulder systems

Using a highly efficient and reliable optimization tool that is based on ideas of geneticalgorithms, we have systematically studied the pattern formation of the two-dimensionalsquare-shoulder system. An overwhelming wealth of complex ordered equilibriumstructures emerge from this investigation as we vary the shoulder width. Withincreasing pressure three structural archetypes could be identified: cluster lattices,where clusters of particles occupy the sites of distorted hexagonal lattices, laneformation, and compact particle arrangements with high coordination numbers.The internal complexity of these structures increases with increasing shoulderwidth.

A 4-$\mu\hbox{W}$ CMOS Front End for Particle Detection Applications

A complete low-power front end for particle detection applications is presented. The front end integrates a charge-sensitive amplifier with a novel adaptive biasing scheme that allows the dc bias currents to be scaled below conventional limits. A downstream peak detector circuit captures the peak value for each detection event, which is then fed to an integrated analog-to-digital converter (ADC). The event-driven ADC is shut off in between detection events to further reduce power consumption. The circuit has been fabricated using a 0.18- μm CMOS technology, with a power consumption ranging between 4 and 20 μW, depending on the particle detection rate. This low-power operation facilitates the development of compact long-life battery-powered remote particle sensors.

Polishing properties of porous silica abrasive on hard disk substrate CMP

Chemical mechanical polishing (CMP) is the only technology to provide global planarisation of topography with a low post-planarisation slope. Abrasive is one of the key influencing factors on the surface quality during the CMP. Traditional silica abrasive is easy to cause polishing scratches since it is compact solid particle. In this work the polishing properties of porous silica abrasive in hard disk substrate CMP were investigated. The results show that the polishing down force and rotating speed have a strong influence on the material removal rate and average surface roughness of the hard disk substrate. After polishing with the slurry containing the porous silica abrasive, a smooth hard disk substrate surface was obtained.

Ti-Al系燃焼合成における自己着火温度に及ぼす主要パラメタの影響(熱工学,内燃機関,動力など)

Relevant to materials synthesis by combustion, spontaneous ignition of compacted mixture has been examined with Ti-Al system taken as a research object. Not only experimental but also theoretical study has been conducted, after confirming that the size ratio, defined as the ratio of compact diameter and particle diameter, and the aspect ratio, defined as the ratio of compact height and diameter, can be useful parameters in correlating experimental results. It is found that with increasing aspect ratio and/or size ratio, the spontaneous ignition temperature decreases within the present experimental conditions, below the melting point 934K of Al. The decrease with increasing aspect ratio is attributed to an establishment of the stationary temperature distribution in the compacted mixture, being balanced between heat release and loss. The decrease with increasing size ratio is attributed to an increase in the particle surface per unit spatial volume of compacted mixture. Effects of mixture ratio have also been examined, showing that the spontaneous ignition temperature decreases with increasing mixture ratio. Effects of the degree of dilution on the spontaneous ignition temperature are also examined. Experimental comparisons with theoretical results have also been conducted and a fair degree of agreement is demonstrated, indicating that the present formulation has captured the essential features of the spontaneous ignition of compacted mixture.

High-temperature tribological behaviors of Ti 2AlNb-based alloys by plasma surface duplex treatment

Plasma tungstening followed by carburization (W-C duplex treatment) was performed on the Ti 2AlNb-based ( O phase) alloy by using the double glow plasma process to enhance its wear resistance. The microstructure and high-temperature tribological behaviors of the un-treated and W-C duplex-treated samples were investigated. The results show that the duplex-treated layer is mainly composed of W 2C or W 6C 2.54 phases and the contents of W and C elements in the alloyed layer change gradually along the depth by surface plasma duplex treatment. The diffusion depth of W is about 12 μm, while the carbon atoms most exist in the depth more than 12 μm. High temperature tribometer tests indicate that the friction coefficient of the W-C duplex-treated layer is approximately 1/6 that of substrate. The wear rate of the duplex-treated layer is about 28% that of the untreated one. So, plasma surface W-C duplex treatment can obviously improve the high-temperature tribological resistance of Ti 2AlNb-based alloy. The tribological mechanism of the duplex-treated layer is discussed by dividing the friction process of the duplex-treated layer into three fluctuate stages. The first stage is the formation of oxide film between W-C duplex-treated layer and counterface. The second stage is the detachment of oxide film, acting as “the third body”. The last stage is the period that the friction and wear occur between the compact particle layer and counterface.

Hollow nanoshell formation and collapse in binary solid solutions with large range ofsolubility

The formation of a solid solution hollow nanoshell from core–shell structure and collapse ofthis nanoshell into a compact particle is modelled by a phenomenological scheme and byMonte Carlo simulation. The cross-over between formation and collapse, and the criteria ofnanoshell formation are analysed.

MO‐D‐BRD‐03: Laser‐Driven Targetry: The Road to Clinical Applications

Purpose: Significant efforts have been made through federal, industrial and institutional funding to develop cost‐effective alternatives to conventional accelerator‐based particle therapy. This presentation reviews the development of laser‐accelerated particle beams as an alternative to conventional accelerators for particle therapy. Method and Materials: Many institutions and research groups have focused on their research on the applications of laser‐accelerated proton and ion beams for medical applications, in particular for radiotherapy treatments. These include extensive investigations of optimal laser parameters and target designs to achieve therapeutic particle energies, compact particle selection and beam collimation designs for novel compact particle therapy systems, dose calculation and treatment optimization for laser‐accelerated proton beams, and system and shielding designs for clinical prototype machines. Fox Chase Cancer Center has established a laser‐ion acceleration facility that consists of a commercial 150 TW laser, custom‐made laser‐pulse compression and target chambers, particle selection and beam collimating devices, dosimetry monitoring systems and shielding constructions. Initial laser‐proton acceleration experiments were performed with thin aluminum and plastic foils as target materials. Particle‐in‐cell (PIC) simulations were carried out to investigate the optimal laser parameters and target configurations to facilitate laser‐proton acceleration and dosimetric studies. Results: The maximum proton energy achieved by laser acceleration was 58 MeV. Our initial testing with a 1018 W/cm2 laser intensity (at 20 TW) produced up to 4 MeV protons with a broad energy spectrum, which confirmed the scalability of laser intensity and maximum proton energy. A compact shielding designed was investigated using Monte Carlo simulations that allows for the installation of the particle therapy head on a small rotating gantry. Conclusion: Laser‐accelerated proton and ion beams have a great potential to replace conventional radiotherapy systems due to its compact design and cost‐effectiveness. Many technical and engineering issues must be solved before a clinical prototype can be built for radiotherapy applications.

MO‐D‐BRD‐02: Dielectric Wall Accelerators for Proton Therapy

A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is being developed for a variety of applications. Research describing an extreme variant of this technology aimed at producing a compact, variable output linear accelerator for proton therapy for cancer will be described along with the technical challenges and issues. The goal of the development is to produce a proton accelerator that will fit in a standard linac vault and deliver intensity modulated proton therapy. Tomotherapy, Inc. has licensed the new accelerator technology from the Lawrence Livermore National Laboratory and the Compact Particle Acceleration Corporation (CPAC) is supporting development of the system. Research sponsored by Tomotherapy, Inc. and CPAC.Conflict of Interest: Some of the co‐authors have a financial interest in Tomotherapy, Inc. and/or CPAC.