Two-dimensional Position Sensitive Detector Research Articles

A multi-electrode two-dimensional position sensitive diamond detector

In multi-electrode devices, charge pulses at all the electrodes are induced concurrently by the motion of the excess charge carriers generated by a single ion. This charge-sharing effect is such that the pulse amplitude at each sensitive electrode depends on the device geometry, its overall electrostatic configuration, and the charge transport properties of the detecting material. Therefore, the cross-analysis of the charge pulses induced at each electrode offers implicit information on the position of the ion impact. In this work, we investigate the two-dimensional position sensitivity of a diamond detector fabricated by deep ion beam lithography. By exploiting the ion beam induced charge technique, the device was exposed to a 2 MeV Li+ ion micro-beam to map the spatial dependence of the charge collection efficiency (CCE) on the nominal micro-beam scanning position. The combination of the CCE maps revealed a two-dimensional position sensitivity of the device with micrometric resolution at the center of the active region.

Fabrication and testing of two-dimensional Micro-Edge Gas Chamber (2D-MEGC)

This work proposes using silver flat ribbon cable to fabricate a new type of position-sensitive gaseous detector. This structure consists of a thin conductive silver of flat ribbon cable (anodes) and thicker copper sheets (cathodes) separated by a plastic insulator. To fix the position of the anodes and the cathodes, a holder compressed the layers. The layers are cut from the edges and polished at several steps to have a smooth surface. These arrays of anodes and cathodes, created by the proposed method, act as a two-dimensional position-sensitive proportional detector. Applying a suitable voltage between the anodes and cathodes produces a strong electric field near the vicinity of the anodes. This electric field multiplies primary electrons generated by ionizing radiation. The experimental results show that for the proposed two Dimensional Micro Edge Gas Chamber (2D-MEGC), at HV1=350 with the gas mixture of (Ar 85% - CO2 15%), the maximum multiplication factor without electric discharge is around 250. All pixels were separately connected to the preamplifier-amplifier setup to test the position sensitivity of 2D-MEGC. As expected for a non-collimated alpha source, the maximum recorded interactions are related to the closest pixel to the radioactive source. The Raether limit is a good benchmark concerning the quality of fabricated gaseous detectors. In the best design conditions, this value for Micro Strip Gas Chamber (MSGCs) is 4 × 107. For the fabricated 2D-MEGC, this number is 2.5 × 107. This result shows that the proposed 2D-MEGC performs well despite its simple structure and fabrication.

On the angular anisotropy of the randomly averaged magnetic neutron scattering cross section of nanoparticles.

The magnetic small-angle neutron scattering (SANS) cross section of dilute ensembles of uniformly magnetized and randomly oriented Stoner-Wohlfarth particles is calculated using the Landau-Lifshitz equation. The focus of this study is on the angular anisotropy of the magnetic SANS signal as it can be seen on a two-dimensional position-sensitive detector. Depending on the symmetry of the magnetic anisotropy of the particles (e.g. uniaxial, cubic), an anisotropic magnetic SANS pattern may result, even in the remanent state or at the coercive field. The case of inhomogeneously magnetized particles and the effects of a particle-size distribution and interparticle correlations are also discussed.

Design of a measurement system for measuring geometric errors of a workpiece table during two-axis synchronous motion

With the increasing customer demand for high-precision workpieces, the accuracy performance of CNC machine tools has become an increasingly important hot topic for almost all machine tool manufacturers. For fine surface finish workpieces, the performance of multi-axis synchronous motion has a significant impact on lathe processing. Accordingly, it is necessary to calibrate and identify the geometric errors of the workpiece table during multiple-axis synchronous motion. Therefore, this study proposes a novel noncontact optical measurement system for measuring the geometric errors of the workpiece table while the two axes are moving simultaneously. In addition, the horizontal CNC lathe machine iTC-2000LM, produced by Tongtai machine & tool Co., Ltd., was taken as the research vehicle. The proposed measurement system comprises an optics module composed of several reflectors, lenses, and cubic beam splitters; a sensing module composed of multiple two-dimensional position-sensitive detectors (PSDs); and a laser. Based on the principle of geometric optics theory and the optical triangulation method, complete mathematical models that describe the geometric errors of the workpiece table during two-axis synchronous motion were established using the skew-ray tracing method. Additionally, the essential features of the proposed measurement system were verified using the optical design software Zemax. Finally, a laboratory prototype system was constructed to experimentally verify the proposed measurement system. As mentioned above, the main contribution of this study is to design a novel and highly efficient measurement system with established measurement mathematical models and experimental verifications.

The latest progress on neutron texture diffractometer at China Advanced Research Reactor

The first neutron texture diffractometer in China was built at the China Advanced Research Reactor (CARR). This neutron texture diffractometer has a high neutron intensity, moderate resolution and a neutron wavelength of 1.48 Å, which is suitable for studying the bulk textures in commonly used metals or alloys. The neutron texture diffractometer is now equipped with a two-dimensional position-sensitive detector, high temperature furnace and loading device after several upgrades. Now in-situ texture measurements can be performed on the texture diffractometer. A detailed description of the instrument and its performance characteristics are presented in this paper.

AXEAP: a software package for X-ray emission data analysis using unsupervised machine learning.

The Argonne X-ray Emission Analysis Package (AXEAP) has been developed to calibrate and process X-ray emission spectroscopy (XES) data collected with a two-dimensional (2D) position-sensitive detector. AXEAP is designed to convert a 2D XES image into an XES spectrum in real time using both calculations and unsupervised machine learning. AXEAP is capable of making this transformation at a rate similar to data collection, allowing real-time comparisons during data collection, reducing the amount of data stored from gigabyte-sized image files to kilobyte-sized text files. With a user-friendly interface, AXEAP includes data processing for non-resonant and resonant XES images from multiple edges and elements. AXEAP is written in MATLAB and can run on common operating systems, including Linux, Windows, and MacOS.

Algorithms and Programs for Express-Analysis of List-Mode Data of Neutron Scattering, Measured on Two-Dimensional Position-Sensitive Detectors with a Delay Line Using Data Acquisition Systems Based on CAEN Digitizers

Algorithms and Programs for Express-Analysis of List-Mode Data of Neutron Scattering, Measured on Two-Dimensional Position-Sensitive Detectors with a Delay Line Using Data Acquisition Systems Based on CAEN Digitizers

Development and testing of a muti-sensor measurement system for roundness and axis straightness errors of deep-hole parts

Precision deep-hole parts are widely used in various fields of industrial production. Their machining quality has a significant impact on fatigue limit, geometric accuracy, and stability of products. Since roundness and axis straightness errors are essential technical indexes to evaluate the machining quality of deep-hole parts, their accurate measurement is essential to ensure the performance of related products. In this study, a multi-sensor integrated system that can measure two kinds of shape errors simultaneously was developed based on laser displacement sensor, circular grating, two-dimensional position-sensitive detector (PSD) and laser interferometer. It is suitable for deep-hole parts with a diameter of 150–165 mm and a length of 600–20000 mm. Furthermore, the uncertainty analysis models of roundness and axis straightness errors for this system were constructed. Eventually, the effectiveness of the measurement system was successfully verified through experiments.

HRTex: a high-resolution texture data processing tool for monochromatic neutron diffraction based on the pixel projection method

HRTex is a new texture data processing tool for two-dimensional position-sensitive area detectors on monochromatic neutron diffractometers. With the aim of improving the resolution and accuracy of pole figure calculations, HRTex treats the raw data of the area detector for each pixel and projects the intensity of each pixel directly onto a high-resolution pole figure. With the resultant refinement of the resolution, HRTex can distinguish close texture peaks with a flexible resolution setting and reduced information loss. Test results of HRTex on the data sets of two samples measured by two different neutron facilities are analysed, and the improvements in accuracy, resolution and efficiency of the pole figure calculation are discussed.

A proof-of-principle experiment on a new diagnostic tool for determining beam sizes from angular distributions of parametric X-ray radiation

A previously proposed technique for measuring the transverse sizes of an electron beam was verified experimentally by comparing the angular distributions of parametric X-ray radiation in a thin crystal for two distances between the crystal and the detector. The measurements were performed on a 255-MeV electron beam incident on a 20 μm-thick silicon crystal. The angular distributions of parametric X-ray radiation were measured using an imaging plate as a two-dimensional position-sensitive detector. The obtained horizontal and vertical beam sizes were in good agreement with the results of measurements by optical transition radiation. The proposed method would be useful for electron beam diagnostics for recently advanced linear accelerators where optical transition radiation cannot be used as a beam profile monitor owing to the coherent effect.

2D Position-Sensitive Hybrid-Perovskite Detectors.

Hybrid organic-inorganic perovskites (HOIPs) have emerged as a versatile class of semiconductors for numerous optoelectronic applications. Here, we demonstrate light-excitation-dependent two-dimensional (2D) position-sensitive detectors (PSDs) using a mixed-phase perovskite, FA0.83Cs0.17Pb(I0.9Br0.1)3, as the active semiconductor, incorporated within a five-terminal device geometry. The light-induced lateral photovoltage, which is initiated by selective charge transfer across the metal-perovskite barrier interface, is utilized to achieve the excitation-position-dependent electric response. The 2D PSD devices exhibit a spatially dependent linear variation of the photosignal with sensitivity >50 μV mm-1 and a low position detection error (1-2%), making them suitable for applications such as quadrant detectors. Further, it is observed that the device architecture plays a key role in controlling the dynamics and linearity of the HOIP PSDs. The large active area devices (up to ∼2 cm × 2 cm) exhibit a distinct spatial variation of the photosignal. We utilize the functionality of the PSD device for light-tracking applications by implementing a continuous detection scheme.

A Compact Spectrometer for Heavy Ion Experiments in the Fermi energy regime

A Compact Spectrometer for Heavy IoN Experiments (CSHINE) has been recently built for the studies of heavy ion reactions at intermediate energies. CSHINE consists of a Si-Si-CsI telescope array and a parallel plate avalanche counter (PPAC) array. Each telescope consists of a thin single-sided silicon strip detector and a thick double-sided silicon strip detector backed by a 3 × 3 CsI(Tl) crystal hodoscope. The thicknesses of the silicon detectors are optimized in order to identify various types of light charged particles in a wide energy range. PPAC is a large-area two-dimensional position-sensitive gas detector, which records fission fragments with the intrinsic efficiency of approximately 100% but filters out light charged particles at properly selected working conditions. In the phase-II run, four Si-Si-CsI telescopes and three PPACs have been installed and operated in the beam experiment with 25 MeV/u Kr+Pb reactions. Particle identification for isotopes from Hydrogen to Boron has been achieved with the Si-Si-CsI telescopes, while excellent timing and position resolution have been achieved with the PPACs.

Observation of parametric X-ray radiation for the asymmetric Laue geometry

Angular distributions of parametric X-ray radiation from 255-MeV electrons in a thin Si crystal have been investigated for asymmetric Laue geometries using an imaging plate as a two-dimensional position-sensitive X-ray detector. The peak intensities of parametric X-ray radiation observed for (111) and (1¯1¯ 1) reflections, normalized by taking into account the effective target thickness and the transmission fraction of X-rays in the crystal, coincided within several percent. A large intensity difference depending on the asymmetry parameter, which is predicted by a dynamical theory dealing with the asymmetric Laue geometry, was not observed under the present experimental conditions. This indicates that the dependence of angular distributions of parametric X-ray radiation on the asymmetry parameter is negligibly weak, i.e., that it can be well explained by the well-established kinematical theory and dynamical theory as well as those for symmetric Laue and Bragg geometries.

A technique for measurement of a prism apex angle by optical angle sensors with a reference artefact

A new technique for measurement of the apex angle of a right-angle prism is proposed. A reference artefact is newly employed as the datum for angle measurement, and the apex angle of a target prism is measured by detecting its deviation from that of the reference artefact by using a pair of optical angle sensors. At first, the principle of the apex angle measurement with the reference artefact and the optical angle sensors are addressed. After that, an optical angle sensor capable of evaluating various sizes of right-angle prisms over a large measurement range is designed and developed. A two-dimensional position-sensitive detector is employed as the photodetector for the optical angle sensor so that a high resolution and a wide measurement range can be achieved simultaneously. To avoid the influence of the interference between a directly-reflected beam and an internally-reflected beam when measuring a face of a right-angle prism, the optical setup is designed to have a laser beam that is made incident to a measurement surface with an oblique incidence. After the design and development of the optical angle sensor, the measurement system has been developed and some basic experiments are carried out to evaluate the basic performance of the developed optical angle sensor. The feasibility of the proposed technique of the prism apex angle measurement is also demonstrated through experiments and theoretical measurement uncertainty analysis based on GUM.

Investigation of O2-X (X = Pyrrole or Pyridine) Cluster Photodissociation Near 226 nm.

We have recorded the O-atom velocity map photofragment ion images resulting from the photodissociation of O2-pyrrole and O2-pyridine clusters near 226 nm. To record the images, the O-atom photoproduct was state-selectively ionized and projected onto a two-dimensional (2D) position-sensitive detector. The resulting ion images from the clusters show evidence for three dissociation pathways. In the images from either cluster, we observe an isotropic process with kinetic energy near the one-photon limit, which is due to dissociation of the cluster into molecular subunits followed by secondary dissociation of molecular oxygen. Both O2-pyrrole and O2-pyridine also show a low kinetic energy process that appears to be isotropic in nature. This low kinetic energy process likely results from dissociation of the cluster resulting in significant internal energy in the organic fragment followed by secondary dissociation of O2. Finally, our ion images for O2-pyrrole show O atoms resulting from a two-photon dissociation channel, which has been previously attributed to the formation and subsequent photodissociation of excited O2 (a 1Δg). At similar laser intensities, O2-pyridine does not show significant dissociation through the channel producing O2 (a 1Δg); however, this channel shows a laser intensity dependence for O2-pyridine.

Nonlinear correction of 2-D PSD for pulsive excitation based on steady-state response results

Position sensitive detectors (PSDs) have been spotlighted as effective position sensors in terminal navigation of laser semi-active guided weapons. However, it remains an ongoing challenge to improve linearity, especially under impulsive excitation. In this paper, the response of the PSD for continuous light excitation is proposed for the first time to correct the PSD response results under pulsive excitation. After establishing the mathematical model of the two-dimensional PSD, the response results under different illumination excitation are simulated and analysed, which theoretically proves the feasibility of the correction method in this paper. Finally, the experiment is carried out with PSD (S5990-01). The results reveal that the distortion degree of the PSD response results is more obvious with the decrease of pulse width under pulse illumination. The impulse response result can be linearly mapped into a steady-state response result with the range of slope values being 0.403∼0.614 and intercept values being -0.098∼0.106.

Modeling and Simulation of Two-Dimensional Position Sensitive Detector (PSD) Sensor

This paper presents Modeling and Simulation of Two-Dimensional Position Sensitive Detector (PSD) using MATLAB. PSD is an Optical Position Sensor (OPS) that can measure a position of a radiation spot in one or two-dimensions on a sensor surface. Unlike discrete elements such as Charge-Coupled Device (CCD), it provides continuous position data, features high position resolution and high-speed response which give this paper its importance. The sensor used consists of two-dimensional array of photodiodes. The sensor has four output photocurrents that change according to the position of incident radiation on the surface. The work is divided into three parts of Modeling and Simulation; the first part is a single photodiode, Second part is one-dimensional array of photodiodes and the third one is two-dimensional array of photodiodes. The tool used to do the simulation is MATLAB software because it is professional and accurate tool, it has photodiode element and it is possible to control the beam of incident light. This research can be useful for Acquisition; Pointing and Tracking (APT) systems where this sensor will give the necessary data to do tracking operation. Proteus software was also been used as a secondary tool.

Space-slice ion imaging: High slice resolution imaging in the polarization plane of arbitrarily polarized ionizing light

We present a conceptually new, slit-based slice imaging technique for ion-imaging experiments, offering a way for high slice resolution imaging in the polarization plane of an ionizing laser pulse. In the present method, a mechanically adjustable slit is installed in the drift region of the flight of the ions so that only a thin central slice of a three-dimensionally expanding ion cloud (Newton sphere) passes through the slit. The sliced cloud is then projected onto a two-dimensional position-sensitive ion detector installed parallel to the slice plane. Compared to the conventional two-dimensional imaging, the present “space-slice imaging” scheme has two principle novelties: (1) The slit acts as an ideal gate for the slicing, and a slice resolution of 1% or higher can be achieved, in principle, using submillimeter slit width for a typical a few-centimeter ion cloud. (2) The imaging plane can be automatically parallel to the polarization plane of a laser pulse regardless of the state of polarization, resulting in a hitherto unrealized “camera angle.” We developed a space-slice ion imaging apparatus to realize and validate the present scheme. To evaluate its performance, we carried out the Coulomb explosion imaging of the N2 molecule. By adjusting slit width, slicing up to approximately 0.33% was achieved without remarkable image distortion. The polarization-dependent imaging shows that the ejection angles of ions can be directly read from the observed images obtained with any polarization states. The present imaging measurements in the laser polarization plane opens new avenues for the study of laser-induced dynamics; these dynamics cannot be fully characterized with the existing two-dimensional setups. As an example, we applied the present approach to the time-resolved imaging of a laser-driven rotational wave packet of N2, using a circularly polarized exploding pulse as an isotropic probe in the imaging plane. We successfully observed clear time-dependent images containing full spatiotemporal information of the wave packet dynamics. Details of the concept, design, and operation of our apparatus are presented in the present paper.

Tracking Control of a Maglev Vibration Isolation System Based on a High-Precision Relative Position and Attitude Model.

The maglev vibration isolation system exhibits excellent micro-vibration isolation performance (0.01 Hz to 100 Hz band) in the space environment. However, a collision between the base and the floating platform may occur in an ultra-low frequency range (≤0.01 Hz). To avoid collision, the relative position and attitude between the base and the floating platform needs to be accurately tracked and controlled. In this study, a novel measurement method with four groups of two-dimensional position-sensitive detectors equipped with four laser light sources was proposed. A high-precision relative position and attitude measurement model was established based on the geometric relationship of space coordinates. A proportional-differential (PD) fixed-point control algorithm was adopted to realize tracking control. The control performance of the system was evaluated through simulation. Experiments were also carried out to verify the stability of the system and the precision of the control algorithm. A maglev vibration isolation system prototype was constructed and a test system was established. The proposed relative position and attitude measurement model was verified and the six degrees of freedom relative position and attitude response of the system was tested. Based on the measurement model, the tracking control of the system was proven to have high precision.

Attitude measurement and simulation of two-dimensional position sensitive detector

Aiming at the problems of high error rate of quantum key distribution of physical star and inaccurate location information of motion platform in space, using partial differential equations and finite element tool values to analyze the potential field distribution of PSD. Combined with MATLAB software theory derivation and model simulation for the application of the lateral photoelectric effect of two-dimensional photoelectric position sensor in three-dimensional attitude measurement, especially deepening the theoretical and simulation aspects of lateral photoelectric effect. The experimental data analysis shows that the 2D-PSD detector can realize the displacement resolution precision of XY axis 2um and the polarization angle measurement accuracy within 0.5°of the working interval, which proves the feasibility of 2D attitude measurement by 2D-PSD.