Quartz Bar Research Articles

Charged particle identification performance of the TOP counters in Belle II

The Time-Of-Propagation (TOP) counter is a novel ring-imaging Cherenkov detector that primarily consists of a quartz bar radiator, micro-channel plate photomultipliers and front-end readout electronics. These TOP counters are installed in the central region of the Belle II detector to provide the crucial information on the charged particle identification (PID). Here, we present an overview of PID studies in Belle II, with a focus on the performance of the TOP detector. The results presented are from the recently recorded data which show reasonable agreement with the expectations from the simulation studies.

Beam test results of NDL Low Gain Avalanche Detectors (LGAD)

A High-Granularity Timing Detector (HGTD) is proposed based on the Low-Gain Avalanche Detector (LGAD) for the ATLAS experiment to satisfy the time resolution requirement for the up-coming High Luminosity at LHC (HL-LHC). We report on beam test results for two proto-types LGADs (BV60 and BV170) developed for the HGTD. Such modules were manufactured by the Institute of High Energy Physics (IHEP) of Chinese Academy of Sciences (CAS) collaborated with Novel Device Laboratory (NDL) of the Beijing Normal University. The beam tests were performed with 5 GeV electron beam at DESY. The timing performance of the LGADs was compared to a trigger counter consisting of a quartz bar coupled to a SiPM readout while extracting reference SiPM by fitting with a Gaussian function. The time resolution was obtained as 41 ps and 63 ps for the BV60 and the BV170, respectively.

Bar adsorptive microextraction device coated with polyimide microsphere assembled by nanosheets combined with thermal desorption-gas chromatography for trace analysis of nitroaromatic explosives in environmental waters

Polyimide (PI) microspheres assembled by nanosheets were used for bar adsorptive microextraction (BAμE) for the first time. The PI microsphere possessed self-organized hierarchical nanostructure, large specific surface area (170 m2/g) and good thermostability (up to 400 °C). The BAμE device was prepared by adhering the PI microspheres on a quartz bar with Kapton double sided tape. Trace nitroaromatic explosives in environmental waters were extracted by the BAμE device, desorbed by thermal desorption (TD), and analyzed by gas chromatography-mass spectrometry (GC–MS). The reproducibility of five BAμE devices prepared in parallel was less than 13.0% (expressed as relative standard deviation, RSD). The BAμE device could stand up to 30 extraction/desorption cycles without decrease of extraction efficiency. The results of method validation showed that the BAμE-TD/GC–MS method possessed wide linearity (0.05–50 μg/L or 0.05–20 μg/L), high correlation coefficients (> 0.9987), good precision (RSDs < 11.8%), low detection limits (0.005–0.013 μg/L) and high enrichment factors (528–1410). Relative recoveries were in the range of 72.2–122.6% with RSDs between 0.1% and 10.5% for real water samples. These results proved that the proposed method was a good choice for determination of organic pollutants in water samples.

Polybenzimidazole Solid-Phase Microextraction Bar Combined with Thermal Desorption–Gas Chromatography for Determination of Triazine Herbicides in Environmental Waters

In this work, polybenzimidazole (PBI) was used as extraction phase for solid-phase microextraction (SPME) combined with thermal desorption and gas chromatography–mass spectrometry (SPME/TD–GC–MS) to detect triazine herbicides in environmental waters. PBI with high thermostability (up to 370 °C) was coated on the quartz bar by the immersion–precipitation phase transformation method. Key parameters including extraction temperature, stirring rate, pH value, ionic strength, extraction time, desorption temperature and desorption time were optimized. The SPME/TD–GC–MS method showed the advantages of wide linearity (0.05–20 μg L−1) with good correlation coefficients (> 0.99), good precision (RSDs < 8.7%), low detection limits (0.0013–0.010 μg L−1), good reproducibility among SPME bars (< 8.8%), and long lifetime of more than 30 extraction/desorption cycles. Finally, the method was applied to determine triazines in real water samples including tap water, pond water, and river water. The relative recoveries were between 70.5 and 103.5% with RSDs ranging from 0.1 to 8.7%. These results indicate that PBI is a promising candidate for SPME extraction phase, especially for the determination of polar analytes combined with TD–GC–MS.

Calibration and commissioning of the Time Of Propagation PID detector at the Belle II Experiment

Abstract The Time Of Propagation (TOP) counter is a novel particle identification detector which relies on the precise detection time of Cherenkov photons produced by charged particles traversing a quartz bar. The TOP counter is constituted by 16 modules that cover the barrel region of the Belle II detector. Each module is instrumented with 32 Micro-Channel-Plate Photo-Multiplier-Tube (MCP-PMT) detectors, which are read out by dedicated fast waveform-sampling front-end electronics. After recalling the performance goals and stringent design requirements of the TOP counter, a comprehensive overview of its calibration strategies will be given. The status of the integration with the other Belle II sub-detectors and the performance during the commissioning phase with cosmic ray data will be presented, along with a preliminary study of the first SuperKEKB collision events.

High-speed large area atomic force microscopy using a quartz resonator

A high-speed atomic force microscope for scanning large areas, utilizing a quartz bar driven close to resonance to provide the motion in the fast scan axis is presented. Images up to 170 × 170 μm2 have been obtained on a polydimethylsiloxane (PDMS) grating in 1 s. This is provided through an average tip-sample velocity of 28 cm s−1 at a line rate of 830 Hz. Scan areas up to 80 × 80 μm2 have been obtained in 0.42 s with a line rate of 1410 Hz. To demonstrate the capability of the scanner the spherulitic crystallization of a semicrystalline polymer was imaged in situ at high speed.

Coupled Catalytic/Gas Phase Ignition of Propane-Oxygen-Inert Mixtures on an Isothermally Heated Platinum Filament Supported on Quartz Bar

The ignition of gaseous flammable mixtures on catalytically active hot solid surfaces is an intricate process implying the tight interaction between surface and gas phase reactions. The paper presents the results obtained from the study of coupled catalytic-gas phase ignition of propane-oxygen-inert mixtures on an isothermally heated platinum filament stabilized on a thin quartz bar, measuring the induction periods, ti, rates of heat release, (dQr/dt)t and minimum ignition energies, Qmin. The experiments were conducted at different initial pressures between 73 and 101 kPa and filament temperatures between 1080 and 1184 K for 2.68% propane-air mixture and 4.02% propane-air mixture diluted with Ar or N2 in ratio 2:1. For any total pressure, the fuel concentration is the same in each mixture, the complementary composition containing the necessary oxygen for complete combustion and inerts or/and excess oxygen. The measured properties were rationalized using Arrhenius-type kinetic equations.

Beam test results of a 16 ps timing system based on ultra-fast silicon detectors

In this paper we report on the timing resolution obtained in a beam test with pions of 180GeV/c momentum at CERN for the first production of 45µm thick Ultra-Fast Silicon Detectors (UFSD). UFSD are based on the Low-Gain Avalanche Detector (LGAD) design, employing n-on-p silicon sensors with internal charge multiplication due to the presence of a thin, low-resistivity diffusion layer below the junction. The UFSD used in this test had a pad area of 1.7mm2. The gain was measured to vary between 5 and 70 depending on the sensor bias voltage. The experimental setup included three UFSD and a fast trigger consisting of a quartz bar readout by a SiPM. The timing resolution was determined by doing Gaussian fits to the time-of-flight of the particles between one or more UFSD and the trigger counter. For a single UFSD the resolution was measured to be 34ps for a bias voltage of 200V, and 27ps for a bias voltage of 230V. For the combination of 3 UFSD the timing resolution was 20ps for a bias voltage of 200V, and 16ps for a bias voltage of 230V.

Cherenkov detector for beam quality measurement

A new detector to measure the machine induced background at larger radii has been developed and installed in the CMS experiment at the LHC. It consists of forty modules, each comprising a quartz bar read out by a photomultiplier tube. Since Cherenkov radiation is emitted in a forward cone around the charged particle trajectory, these detectors can distinguish between the arrival directions of the machine induced background and the collision products. The back-end electronics consists of a uTCA readout with excellent time resolution. The installation in the CMS is described and first commissioning measurements with the LHC beams in Run II are presented.

Time-of-Propagation Counter for the LEPS

We have tested a time-of-propagation (TOP) counter, which is a ring-image Cherenkov counter utilizing the position and propagation time of the Cherenkov light produced by particles moving in a quartz radiator. Position-sensitive photomultipliers (PMTs) are attached to the end of the quartz bar to detect the produced Cherenkov-ring image. The velocity of the charged particle was determined by comparing the time-of-propagation spectra of the Cherenkov light with the results of Monte Carlo simulation. From analysis of the test experiment using the 1.22-GeV/c electron beam at SPring-8, we determined the velocity of the electron beam to be 1.001 with a resolution of 0.002. On the basis of this study, we suggest a full setup for the detector for separating pions and kaons in the momentum region from 1.5 to 2.0 GeV/c for a beam angle of less than 6 $^\circ$ , by more than four standard deviations.

Performance of the MCP-PMT for the Belle II TOP counter in a magnetic field

The time of propagation (TOP) counter is a novel particle identification device for the Belle II experiment, utilizing the ring imaging Cherenkov technique. It is composed of a 2.7m long quartz bar and 32 micro channel plate photomultiplier tubes (MCP-PMTs) attached on the end of the bar. The MCP-PMT has a typical quantum efficiency of 28%, a photoelectron collection efficiency of about 55%, and a transit time spread (TTS) less than 50ps for single photon detection. Since the TOP counters are installed in the 1.5T magnetic field of the Belle II detector, the MCP-PMTs are required to keep those characteristics with gain of more than 5×105 in the magnetic field. Therefore, we investigated gain, TTS, and single photon detection efficiency of the MCP-PMTs in the magnetic field and found that they satisfy the requirements. We are starting complete inspections for more than 500 MCP-PMTs, and have inspected up to 87 MCP-PMTs.

The assembly of the Belle II TOP counter

A new type of ring-imaging Cherenkov counter, called TOP counter, has been developed for particle identification at the Belle II experiment to run at the SuperKEKB accelerator in KEK, Japan. The detector consists of 16 identical modules arranged azimuthally around the beam line. The assembly procedure for a TOP module is described. This procedure includes acceptance testing of the quartz mirror, prism, and quartz bar radiators. The acceptance tests include a chip search and measurements of bulk transmittance and total internal reflectance. The process for aligning and gluing the optical components together is described.

A new type of Time-Of-Propagation (TOP) Cherenkov detector for particle identification

A new type of particle identification (PID) detector based on measurements of 1-D Time-Of-Propagation (TOP) and 1-D space information is described. Geant4 toolkit is used to simulate the propagation of Cherenkov photon in thin quartz bar radiator. Contributions to the timing uncertainty are discussed. The π/K separability (S0) is defined and its dependence on the particle momentum, incident angle and propagation length are studied, respectively.

Large scan area high-speed atomic force microscopy using a resonant scanner

A large scan area high-speed scan stage for atomic force microscopy using the resonant oscillation of a quartz bar has been constructed. The sample scanner can be used for high-speed imaging in both air and liquid environments. The well-defined time-position response of the scan stage due to the use of resonance allows highly linearized images to be obtained with a scan size up to 37.5 mum in 0.7 s. The scanner is demonstrated for imaging highly topographic silicon test samples and a semicrystalline polymer undergoing crystallization in air, while images of a polymer and a living bacteria, S. aureus, are obtained in liquid.

Hydrogen Sensor Based on Au and YSZ/HgO/Hg Electrode for in Situ Measurement of Dissolved H2 in High-Temperature and -Pressure Fluids

Gold as a hydrogen-sensing electrode for in situ measurement of dissolved H2 in aqueous solutions under extreme conditions is reported. The dissolved H2 sensor, constructed with a Au-based sensing element and coupled with a YSZ/HgO/Hg electrode, is well suited for determining dissolved H2 concentrations of aqueous fluids at elevated temperatures and pressures. The Au electrode is made of Au wire mounted in a quartz bar, which can be pressurized and heated in the high-pressure and -temperature conditions. The Au-YSZ sensor has been tested for its potential response to the concentrations of dissolved H2 in fluids by using a flow-through reactor at high temperatures up to 400 degrees C and pressures to 38 MPa. Good sensitivity and linear response between the hydrogen concentrations in the fluids and the H2 sensor potentials are reported for hydrogen gas in the concentration range of 0.1-0.001 M H2 in aqueous fluids at temperatures up to 340 degrees C and 30 MPa. Nernstian response of the cell potential to dissolved H2 in fluids was determined at 340 degrees C and 30 MPa, described as follows: DeltaE = 0.9444 + 0. 0603 log m H2 The experimental results indicate that the Au-YSZ/HgO/Hg cell can be used to measure the solubility of H2 in aqueous fluid at temperatures and pressures near to the critical state of water. Thus, this type of Au hydrogen sensor could be easily used for in situ measurement of H2 in hydrothermal fluids in a high-pressure vessel, or at midocean ridge, due to its structure of compression resistance.

Two-dimensional small-angle X-ray scattering from as-grown and heat-treated synthetic quartz

The small-angle X-ray scattering (SAXS) in as-grown and heat-treated quartz crystals was investigated as a function of the azimuth angle around the primary beam. For this, samples parallel to (10\bar 10) were extracted from Z- and −X-growth sectors of a synthetic quartz bar which had the OH content evaluated by infrared spectroscopy (IRS). In addition, SAXS and IRS were independently recorded as a function of heating temperature. As a result, the two-dimensional SAXS images revealed an anisotropic pattern randomly decorated by low-intensity Kossel lines. The intensities were projected along specific directions or were axially integrated around the primary beam. It was observed that the Porod invariant (Q) increased and the Kossel lines moved slightly to higher q values with increasing temperature. The effect of the sample orientation on the Q value and the lack of a clear relationship between Q and OH content suggested that the diffuse scattering due to the periodicity of the crystal lattice played an important role in the small-angle scattering of quartz. The net scattering intensities produced by heat-treatment at 873 K were attributed to molecular water aggregates created by the diffusion of as-grown OH defects.

Research on the torsional effect of piezoelectric quartz

In this paper, the torsional effect of piezoelectric quartz is investigated by the piezoelectricity, the elasticity theory and the theory of electromagnetism. First using the torsion theory of an anisotropic bar the torsional stress is deduced. Then, by means of the piezoelectric equation we calculate the volume and surface bound charge densities due to torsion, and the finite element method is used to simulate the electric field distribution in a quartz bar with torque applied. Based on the theoretical analyses, the four detection electrodes are effectively arranged on the surfaces of the quartz bar. The theoretical and experimental results both show that the polarization charge by torsion is linear with a torque applied. Finally, in order to obtain the maximum torsion charge sensitivity, the cutting angle optimization is performed. The research on the torsional effect of piezoelectric quartz will provide a new method for torque measurement.

Signal processing in photoacoustic detection of phase transitions by means of the autospectra correlation-based method: Evaluation with ceramic BaTiO3

This work describes a simple numerical procedure which, when applied to digitally recorded photoacoustic (PA) signals, allows the construction of thermal profiles (rS,drS/dT) to determine: the transition order, the phase transition temperature (Tc), and the phase transformation temperature range (ΔT), on samples, which undergo low–high transitions. During continuous heating of the sample, the ultrasonic signal was generated using a pulsed laser beam incident on a surface and detected on the opposite surface of the sample using a long quartz bar attached to a piezoelectric sensor. The thermal profile, rS, is built from a sequence of the ordinary correlation coefficients ri associated with an interval of temperature. The ri coefficients are calculated from amplitude spectra pairs. The amplitude spectra are obtained via fast Fourier transforms from original PA records. This procedure is applied on samples of bulk ceramic BaTiO3 to obtain their thermal behavior. The PA signal and temperature sample were registered every 0.2°. The samples were heated from room temperature to 137 °C at a rate of 0.1 °C min−1. The thermal profile rS shows the entire thermal history including the structural phase transition from tetragonal to cubic (T-C), which appears as a jump on the graph within an uncertainty of 2%. The drS/dT profile shows that the T-C phase transformation occurs over a range of temperatures. The results are in agreement with those reported in the literature.

626 植物油を含有するディーゼル燃料の懸垂油滴燃焼特性

To clarify the evaporation and combustion characteristics of diesel fuel containing vegetable oil, the present study carried out suspended droplet combustion with different fuel mixtures. The experiments used an electric furnace which was kept at high temperatures (973-1273 K) at atmospheric pressure. The quartz bar used has a spherical suspending part (0.6mm diameter), and the droplet was manually placed quickly in the chamber. The evaporation and combustion behaviors of biodiesel fuel, neat rapeseed oil, gas oil-rapeseed oil blends, and gas oil were analyzed with images taken by a high speed video camera. The observations showed boiling phenomena when fuels containing vegetable oil were tested and have a violent transformation of boiling droplets occurred.

Detection of internally reflected Cherenkov light, results from the BELLE DIRC prototype

Abstract The DIRC (Detector of Internally Reflected Cherenkov light) is a new type of ring imaging Cherenkov detector which utilizes precisely machined quartz bars as Cherenkov radiators. Bar quality is determined by both laser and cosmic ray measurements. The Cherenkov photons are transported several meters along the bar until they reach the detector cavity where they are proximity focussed on an array of conventional photomultiplier tubes. Results from a prototype device comprising a 2 × 4 × 240 cm 3 quartz bar read by an array of 480 PMTs are presented. Sample images, which are the first observed in this type of detector, are also shown. Measurements of the light yield (approximately 20 photoelectrons per image) and the angular resolution, which are both in good agreement with Monte Carlo predictions, are shown to lie well within the expected operating tolerances of the DIRC.