Kind Of Detector Research Articles

Quantitative analysis of five antiviral drugs by hydrophilic interaction liquid chromatography-charged aerosol detection

Antiviral drugs are widely used for human and animals. However, the analysis of the mixture of antiviral drugs is a challenge for high performance liquid chromatography, since some of the antiviral drugs have weak UV absorbance and poor retention in reversed phase liq- uid chromatography. A method of hydrophilic interaction liquid chromatography-charged aerosol detection (HILIC-CAD) was optimized for the qualitative and quantitative analysis of five antiviral drugs. In this study, Click TE-Cys was used as the stationary phase and CAD was used as the detector. Various chromatographic conditions including the kind of detector, chromatographic mode, column and mobile phase composition were investigated. Compared to UV-Vis, more antiviral drugs could be detected by CAD, since it is a universal detector. HILIC mode is an alternative to reversed phase liquid chromatography mode. HILIC provides higher sensitivity and unique selectivity to target compounds. After the optimized parameters were obtained, the developed method was used for the quantitative analysis of the five antiviral drugs. As a result, the current method has good repeatability, a wide linear range (0.07-2.28 mg/mL) and good sensitivity (LOQ ≤ 0.04 mg/mL). The RSDs of intra-day and inter-day peak areas were less than 3. 06% and 5. 38% respectively. The above results demonstrated that the current method is sensitive, robust and effective for the separation and determination of these five antiviral drugs.

Recent improvement of a FIB-SEM serial-sectioning method for precise 3D image reconstruction - application of the orthogonally-arranged FIB-SEM.

IntroductionWe installed the first "orthogonally-arranged" FIB-SEM in 2011. The most characteristic point of this instrument is that the FIB and SEM columns are perpendicularly mounted; this is specially designed to obtain a serial-sectioning dataset more accurately and precisely with higher contrast and higher spatial resolution compare to other current FIB-SEMs [1]. Since the installation in 2011, we have developed the hardware and methodology of the serial-sectioning based on this orthogonal FIB-SEM. In order to develop this technique, we have widely opened this instrument to every researcher of all fields. In the presentation, I would like to introduce some of application results that are obtained by users of this instrument. The characteristic points of the orthogonal systemFigure1 shows a difference between the standard and the orthogonal FIB-SEM systems: In the standard system, shown in Fig.1(a), optical axes of a FIB and a SEM crosses around 60deg., while in the orthogonal system (Fig.1(b)), they are perpendicular to each other. The standard arrangement (a) is certainly suitable for TEM lamellae preparation etc. because the FIB and the SEM can see the same position simultaneously. However, for a serial-sectioning, it is not to say the best arrangement. One of the reasons is that the sliced plane by the FIB is not perpendicular to the electron beam so that the background contrast is not uniform and observed plane is distorted. On the other hand, in case of the orthogonally-arranged system,(b), these problems are resolved. In addition, spatial resolution can keep high enough even in a low accelerating voltage (e.g. 500V) because a working distance is set very small, 2mm. From these special design, we can obtain the serial-sectioning dataset from rather wide area (∼100um) with high spatial resolution (Max. 2×2×2nm). As this system has many kinds of detectors: SE, ET, Backscatter Electron(Energy-selective), EDS, EBSD, STEM(BF&ADF), with Ar+ ion-gun and a plasma cleaner, many kinds of signals can be obtained simultaneously.jmicro;63/suppl_1/i5-a/DFU077F1F1DFU077F1Fig. 1.Schematic illustration described (a) a standard type arrangement, (b) an orthogonal type arrangement. Recent topics and Future prospectsWe have applied this instrument for wide area of microstructure analysis; Metals and Alloys, Semiconductor devices, Battery electrodes, Minerals, Biomaterials, and so on. In my presentation, I would like to introduce some of our application results and will discuss about future development of the methodology of a FIB-SEM serial sectioning. As the applied research field becomes wider, various requests for the method were arisen. However, most requests can be summarized as follows: observation of larger area, expansion of applicable sample, obtain many kind of information, linkage with other instruments. AcknowledgmentsThe instrument introduced in this work was installed at NIMS by a part of "Low-carbon research network Japan" funded by the MEXT,Japan.

Measurements and optimization of the lightyield of a TeO2 crystal

Bolometers have proven to be good instruments to search for rareprocesses because of their excellent energy resolution and theirextremely low intrinsic background. In this kind of detectors, thecapability of discriminating α particles from electronsrepresents an important aspect for the background reduction. Onepossibility for obtaining such a discrimination is provided by thedetection of the Čerenkov light which, at the low energies of thenatural radioactivity, is only emitted by electrons. This paperdescribes the method developed to evaluate the amount of lightproduced by a crystal of TeO2 when hit by a 511 keV photon. Theexperimental measurements and the results of a detailed simulation ofthe crystal and the readout system are shown and compared.A light yield of about52 Čerenkov photons per deposited MeV was measured. The effect ofwrapping the crystal with a PTFE layer, with the aim of maximizing thelight collection, is also presented.

Photon-number-resolving detectors for quantum-state engineering: Introduction to the feature issue

Generation and measurement of quantum states of light represent a hot and widely discussed topic in the physical community for their possible applications to quantum optics and quantum information. To this aim, it is desirable that optical states are robust with respect to losses and can be produced and addressed at high rates. In fact, mesoscopic pulsed optical states containing few photons per pulse seem to be the ideal candidates for applications to quantum communication protocols. For all these reasons, during the last two decades many efforts have been devoted to the development of new kinds of detectors that can operate in such a photon-number-resolving domain.

Core axial power shape reconstruction based on radial basis function neural network

The core axial power shape reconstruction method based on radial basis function neural network (RBFNN) is proposed, and 18-node axial core power shape can be reconstructed from 6-segment in-core detector signals or 6-segment ex-core detector signals. Alternating conditional expectation algorithm is also used to validate the effectiveness of RBFNN algorithm. The results show that no matter what kind of detector is used, the RBFNN algorithm performs better than the ACE algorithm. The RBFNN algorithm has a good anti-noise ability when the in-core detector signals with noise are used, while the correct axial power shape can’t be reconstructed from the ex-core detector signals with noise. By analyzing the ex-core axial spatial weighting function’s condition number, the determination of the axial power shape from ex-core detector signals is found to be a typical ill-posed inverse problem. A regularized RBFNN algorithm is used to eliminate this ill-posedness and get the physically meaningful axial power shape.

Multi-shape pulse pile-up correction: The MCPPU code

In spectroscopic measurements with high counting rate, pulse pile-up (PPU) is a common distortion of the spectrum. It is fully ascribable to the pulse handling circuitry of the detector and it is not comprised in the detector response function which is well explained by a purely physical model. Since PPU occurs after the transport inside the detector, this is the first correction to perform in case of spectrum unfolding. Many producers include electronic rejection circuits to limit the appearance of PPU, but it is never suppressed completely. Therefore, it is always necessary to correct PPU distortions after the measurement. In the present work, it is described the post-processing tool MCPPU (Monte Carlo Pulse Pile-Up), based on the MC algorithm developed by Guo et al. (2004, 2005). MCPPU automatically determines the dead time of the counting system and corrects for PPU effects even in the presence of electronic suppression. The capability of allowing a user defined pulse shape makes the code suitable to be used with any kind of detector. The features of MCPPU are illustrated with some examples.

Development of the liquid level meters for the PandaX dark matter detector

The two-phase xenon detector is at the frontier of dark matter direct search. This kind of detector uses liquid xenon as the sensitive target and is operated in two-phase (liquid/gas) mode, where the liquid level needs to be monitored and controlled in sub-millimeter precision. In this paper, we present a detailed design and study of two kinds of level meters for the PandaX dark matter detector. The long level meter is used to monitor the overall liquid level while short level meters are used to monitor the inclination of the detector. These level meters are cylindrical capacitors that are custom-made from two concentric metal tubes. Their capacitance values are read out by a universal transducer interface chip and are recorded by the PandaX slow control system. We present the developments that lead to level meters with long-term stability and sub-millimeter precision. Fluctuations (standard deviations) of less than 0.02 mm for the short level meters and less than 0.2 mm for the long level meter were achieved during a few days of test operation.

Synchronous detector as a new paradigm for automatic microembolus detection

We propose here a new detector paradigm based on synchronous detection. Unlike standard energy detectors, this kind of detector uses the pseudo-cyclostationarity properties of blood Doppler signals. The new detector, which is synchronised with cardiac rhythm, was compared to a gold standard and a standard energy detector. Detectors were evaluated according to clinical recordings from patients with carotid stenoses. The results showed that it was possible to detect inaudible microemboli. The detection rate was improved by 30% and the false alarm rate was below 2%.

Study of solid-conversion gaseous detector based on GEM for high energy X-ray industrial CT.

The general gaseous ionization detectors are not suitable for high energy X-ray industrial computed tomography (HEICT) because of their inherent limitations, especially low detective efficiency and large volume. The goal of this study was to investigate a new type of gaseous detector to solve these problems. The novel detector was made by a metal foil as X-ray convertor to improve the conversion efficiency, and the Gas Electron Multiplier (hereinafter "GEM") was used as electron amplifier to lessen its volume. The detective mechanism and signal formation of the detector was discussed in detail. The conversion efficiency was calculated by using EGSnrc Monte Carlo code, and the transport course of photon and secondary electron avalanche in the detector was simulated with the Maxwell and Garfield codes. The result indicated that this detector has higher conversion efficiency as well as less volume. Theoretically this kind of detector could be a perfect candidate for replacing the conventional detector in HEICT.

Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro‐CT imaging

Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)∕CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al2O3:C crystals. CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB∕c mice weighing 27.1 ± 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated. CTDI measurements were between 78.0 ± 2.1 and 110.7 ± 3.0 mGy for the rat-like phantom and between 169.3 ± 4.6 and 203.6 ± 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse-like phantom. OSLDs exhibited a reproducibility of 2.4% and good linearity was found between 60 and 450 mGy. The energy scaling factor was calculated to be between 1.80 ± 0.16 and 1.86 ± 0.16, depending on protocol used. In phantoms, mean doses to tissue over a whole-body CT examination were ranging from 186.4 ± 7.6 to 234.9 ± 7.1 mGy. In mice, mean doses to tissue in the mouse trunk (thorax, abdomen, pelvis, and flanks) were between 213.0 ± 17.0 and 251.2 ± 13.4 mGy. Skin doses (3 OSLDs) were much higher with average doses between 350.6 ± 25.3 and 432.5 ± 34.1 mGy. The dose delivered during a topogram was found to be below 10 mGy. Use of the multimouse bed of the system gave a significantly 20%-40% lower dose per animal (p < 0.05). Absorbed doses in micro-CT were found to be relatively high. In micro-SPECT∕CT imaging, the micro-CT unit is mainly used to produce a localization frame. As a result, users should pay attention to adjustable CT parameters so as to minimize the radiation dose and avoid any adverse radiation effects which may interfere with biological parameters studied.

Finite Element Simulation of a Novel Nano 3D Semiconductor Detector Fabricated by Anodizing the Aluminium

The unique geometry of micro 3D semiconductor detectors, presents several advantages over conventional planar silicon detectors. But, manufacturing these kind of detectors requires high technology. The novel idea to achieve a high performance and low cost semiconductor detector is using the nanopattern of anodized aluminium as a mask to create nano3D detectors. The simulation results show that this novel nano3D radiation hard semiconductor detector with collection time less than 10 ps and full depletion voltage less than one volt can become increasingly important for possible future upgrades of 3D detectors of the Large Hadron Collider (LHC) at CERN and also medical imaging applications.

Pixel-Level Charge and Current Injection Circuit for High Accuracy Calibration of the DSSC Chip at the European XFEL

This work presents the experimental results from the characterization of the second prototype of a high accuracy (in terms of linearity, mismatch and noise) injection circuit to be used for in-pixel calibration of a large sensor matrix. The circuit was designed for the calibration of the pixel cell unit of a hybrid pixel device, the DEPFET Sensor with Signal Compression (DSSC) chip, for the large format imager at the European X-ray Free Electron Laser (XFEL), but, in principle, it can be used also for other kinds of detectors, e.g., deep N-well monolithic CMOS sensors. In the case of hybrid pixels, the injection circuit is particularly useful to test the functionality of the readout electronics already at the chip level, when no sensor is connected to the chip. Two injection techniques have been investigated: one for a charge sensitive amplification and the other for a transresistance readout channel. The aim of the paper is to describe the architecture of the calibration circuit, which has been implemented in a 130-nm CMOS technology, and to present the results from the characterization of the second prototype.

Proposal for Neutron Scattering Systems for Calibration of Dark Matter Search and Low-Energy Neutrino Detectors

The proposal of two neutron scattering systems for calibration of two-phase cryogenic avalanche detectors with high sensitivity being developed at Budker INP is presented. This kind of detectors is designed for the search of dark matter and low energy neutrino detection, in particular, coherent neutrino scattering on nuclei. Detector calibration is made with a measurement of ionization yield and scintillation quenching factor for low energy recoiling nuclei (in 0.5 to 100 keV range) originating from elastic scattering of neutrons. To provide wide range of recoiling nuclei energies two systems of neutron scattering are proposed. The first one is based on small-sized DD generator of fast (2.45 MeV) monoenergetic neutrons operating on sealed neutron tube. The second one is based on tandem proton accelerator and lithium target and capable of generation of monoenergetic epithermal neutrons with energy up to 100 keV

Compressive Sampling Based Energy Detection of Ultra-Wideband Pulse Position Modulation

Compressive sampling (CS) based energy detectors are developed for ultra-wideband (UWB) pulse position modulation (PPM), in multipath fading environments so as to reduce the sampling complexity at the receiver side. Due to sub-Nyquist rate sampling, the CS process outputs a compressed version of the received signal such that the original signal can be recovered from this low dimensional representation. Using the principles of generalized maximum likelihood (GML), we propose two types of energy detectors for such signals. The first type of detectors involves the reconstruction of the received signal followed by a detection stage. Statistical properties of the reconstruction error have been used for the realization of such kind of detectors. The second type of detectors does not rely on reconstruction and carries out the detection operation directly on the compressed signal, thereby offering a further reduction in the implementation complexity. The performance of the proposed detectors is independent of the spreading factor. We analyze the bit error performance of the proposed energy detectors for two scenarios of the propagation channel: when the channel is deterministic, and when it is Gaussian distributed. We provide exact bit error probability (BEP) expressions of the CS based energy detectors for each scenario of the channel. The BEP expressions obtained for the detectors working on the compressed signal directly can naturally be extended to BEP expressions for the related energy detectors working on the Nyquist-rate sampled signal. Simulation results validate the accuracy of these BEP expressions.

Detector control system for Daya Bay Reactor Neutrino Experiment

The Daya Bay Reactor Neutrino Experiment is to measure the smallest mixing angle θ13.The experiment contains three major experiment halls,Daya Bay near site,Linao near site and far site,and two major kinds of detectors,antineutrino detector which is to detect the antineutrinos by the inverse beta-de...

PyFAI, a versatile library for azimuthal regrouping

2D area detectors like CCD or pixel detectors have become popular in the last 15 years for diffraction experiments (e.g. for WAXS, SAXS, single crystal and powder diffraction (XRPD)). These detectors have a large sensitive area of millions of pixels with high spatial resolution. The software package pyFAI has been designed to reduce SAXS, WAXS and XRPD images taken with those detectors into 1D curves (azimuthal integration) usable by other software for in-depth analysis such as Rietveld refinement, or 2D images (a radial transformation named caking). As a library, the aim of pyFAI is to be integrated into other tools like PyMca or EDNA with a clean pythonic interface. However pyFAI features also command line tools for batch processing, converting data into q-space (q being the momentum transfer) or 2θ-space (θ being the Bragg angle) and a calibration graphical interface for optimizing the geometry of the experiment using the Debye-Scherrer rings of a reference sample. PyFAI shares the geometry definition of SPD but can directly import geometries determined by the software FIT2D. PyFAI has been designed to work with any kind of detector and geometry (transmission or reflection) and relies on FabIO, a library able to read more than 20 image formats produced by detectors from 12 different manufacturers. During the transformation from cartesian space (x,y) to polar space (2θ, χ), both local and total intensities are conserved in order to obtain accurate quantitative results. Technical details on how this integration is implemented and how it has been ported to native code and parallelized on graphic cards are discussed in this paper.

Tests for a new concept of EAS detector for UHE neutrinos

We present results from tests performed at Karlsruhe Institute of Technology (KIT) and at FermiLab Meson Test Beam Facility (FNAL) to study electron-muon separation, time of flight resolution and the acceptance for a new EAS detector concept. The very good time resolution and adjustable orientation of the detector permit to separate upward-moving tracks from downward tracks at any orientation with high efficiency. With these performances the detector can measure interaction products from cosmic neutrinos with zenith angles > 90 degrees, defining a chord through the earth as the interaction path. This kind of detector using SiPM will be a part of a large area array (several square kilometer) designed to measure UHE neutrinos (0.01-100 EeV).

VERITAS: A 128-Channel ASIC for the Readout of pnCCDs and DEPFET Arrays for X-Ray Imaging, Spectroscopy and XFEL Applications

VERITAS (VErsatile Readout based on Integrated Trapezoidal Analog Shapers) is the first 128-channel ASIC developed to read out both the pnCCDs and the DEPFET arrays produced at the MPI-Halbleiterlabor in Munich. These detectors are used in a large variety of scientific applications, ranging from high-speed optical astronomy and X-ray astronomy to the new X-ray Free Electron Laser sources. The main concept of VERITAS is to provide a flexible readout chip able to cope not only with different kinds of detectors, but also with a large set of operating conditions that may require very different noise thresholds and input dynamic ranges. These can vary by more than two orders of magnitude. Every analog channel of VERITAS provides a trapezoidal weighting function. This filtering strategy had never been applied to the pnCCD before. The very first measurements obtained coupling VERITAS with a 128 × 256 pnCCD are shown. With a readout time of 4 μs/line a noise of 3.9 electrons has been measured in the highest gain mode. The resolution obtained on the Mn-Kα peak of a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">55</sup> Fe source is 136 eV for single events. A noise of 30 electrons has been achieved in the lowest gain mode at a speed of 6.4 μs/line. In this low gain setting an input charge up to 2 5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> electrons can be processed. These striking results fulfill the requirements of the main foreseen applications of large-size pnCCDs. In order to further improve the performance and the flexibility of the ASIC, a second version based on a fully differential architecture has been designed. The new topology allows one also to switch with the same ASIC between the source follower and drain current readout of the DEPFET sensors and to reach a processing time of about 2-3 μs/line with an electronics noise ≤10 el. For this reason the second version of VERITAS is very attractive for the proposed ESA X-ray astronomy mission ATHENA.

Strategies of Detection: Interpretive Methods in Experimental Particle Physics, 1930&amp;#x96;1950

Between 1930 and 1950 experimental physicists used cloud chambers, coincidence counters, and nuclear emulsions to study both cosmic rays and radioactive processes. In order to identify what particles they were detecting and to measure their properties, these physicists employed a variety of interpretive strategies. Their choice of strategies depended upon what task they were trying to perform, and what instrument they were using. It is argued that different strategies could be employed using the same instrument, that the same strategy could be used with different instruments, and that different strategies could be used in combination with each other. Analyzing the history of the use of these strategies permits a deeper understanding of how physicists designed experiments and used evidence in drawing conclusions. Attending to the patterns of strategy use also permits new periodizations to be developed in the history of particle physics. In the timeframe considered, it is argued that inferential strategies were used to interpret single images of particle tracks, that evidence aggregation was crucial using all kinds of detectors, and that it was also common to use nuclear physics knowledge to narrow the range of possible interpretations. Beginning in the late 1940s, precision measurement, precision experiment design, and decay mode analysis became prominent strategies in the systematic search for new particles. This history builds on and revises Peter Galison’s history of particle detection practices, which is based on the distinct epistemological ideals he supposes drove experimentation in the “image” and “logic” traditions of detector instrumentation.

Research development of designing flow cells for optical absorption detectors

The optical absorption detector is one of the most commonly used detectors for high performance liquid chromatography (HPLC). As a core part of this kind of detector, the designs of flow cells, where light passes through samples for acquiring samples information, will affect the performance of a detector. In order to enhance the signal to noise ratio of detectors and reduce the bands broadening that come from flow cells, it is necessary to design a flow cell with a longer optical path length and a less cell volume while maintaining the luminous flux. However the limitations of the machining capacity make it difficult to increase the optical path length, reduce the cell volume and keep or increase the luminous flux simultaneously. It is a challenge to optimize the designing and machining of flow cells so as to improve the performance of detectors. This review discusses the development of designing flow cells based on the detection principle in some aspects of increasing the optical path length, reducing the cell volume, taking the advantages of total reflection and so on. At the same time, some of the designs are illustrated in detail. These various ideas and structures are significant references for designing flow cells and developing optical absorption detectors.