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Unlike the conventional electroosmotic flow (EOF) driven by direct current and alternating current electric fields, this study investigates the pulse EOF of Newtonian fluids through a parallel plate microchannel actuated by pulse electric fields. Specifically, the pulses considered encompass triangular and half-sinusoidal pulse waves. By applying the Laplace transform method and the residual theorem, the analytical solutions for the velocity and volumetric flow rate of the pulse EOF associated with these two pulse waves are derived, respectively. The influence of pulse width a ¯ and electrokinetic width K on velocity is further considered, while the volumetric flow rate as a function of time t ¯ and electrokinetic width K is examined separately. A comparison of the volumetric flow rates related to these two pulse waves under varying parameters is also conducted. The research findings indicate that irrespective of the pulse wave, a broader pulse width results in a prolonged period and increased amplitude of the velocity profile. Elevating the electrokinetic width yields higher near-wall velocities, with negligible effect on near-center velocities. It is noteworthy that regardless of the electrokinetic width, the near-wall velocity exceeds that of the near-center during the first half-cycle, while the situation reverses during the second half-cycle. The volumetric flow rate varies periodically with time, initially surging rapidly with electrokinetic width before gradually stabilizing at a constant level. More interestingly, independent of pulse width and electrokinetic width, the volumetric flow rates linked to the half-sinusoidal pulse wave consistently surpass those of the triangular pulse wave. For any pulse width, the volumetric flow rates corresponding to the two pulse waves grow with higher electrokinetic widths, especially prominent at alternating intervals of the two half-cycles within a complete cycle. These findings have important implications for improving the design and optimization of microfluidic devices in engineering and biomedical applications utilizing pulse EOF. [ABSTRACT FROM AUTHOR]

We evaluated the dissociation of isolated gas-phase nucleobase molecules induced by mega electron volt (MeV)-energy ions to gain fundamental insights into the reactions of nucleobases upon fast ion irradiation. We studied five nucleobase molecules—adenine, guanine, cytosine, thymine, and uracil—as gas-phase targets. We compared the fragmentation patterns obtained from carbon ion impacts with those obtained from proton impacts to clarify the effect of heavy ion irradiation. We also compared the results with electron impact and photoionization results. In addition, we identified several delayed fragmentation pathways by analyzing the correlation between fragment pairs generated from singly and doubly charged intermediate ions. To determine the lifetimes of delayed fragmentation from singly charged intermediate ions, we evaluated the detection efficiencies of the microchannel plate detector for the neutral fragment HCN as a function of kinetic energy using a new methodology. As the first demonstration of this method, we estimated the lifetimes of C5H5N5+ generated by 1.2-MeV C+ and 0.5-MeV H+ collisions to be 0.87 ± 0.43 and 0.67 ± 0.09 µs, respectively. These lifetimes were approximately one order of magnitude longer than those of the doubly charged intermediate ion C5H5N52+. [ABSTRACT FROM AUTHOR]

We report the experimental measurements of the decay rate of polar cesium nD5/2 − 6S1/2 Rydberg-ground molecules with a large principal quantum number range of 35 ≤ n ≤ 40. Rydberg molecules are prepared employing the method of two-photon photoassociation and the molecular (atomic) ions, due to autoionization (blackbody photoionization), are detected with a microchannel plate detector. The decay rate Γ of the vibrational ground state of the deep and shadow bound molecules for triplet (TΣ) and mixed singlet-triplet (S,TΣ) are measured by fitting the molecular population with the exponential function. Comparing with the parent atom, the decay rate of the polar Rydberg-ground molecule shows an obvious increase with a magnitude of a few μs. The possible dissociation mechanism of polar Rydberg-ground molecules including a collisional decay, blackbody induced decay, and coupling of adjacent Rydberg states and tunneling decay are discussed in detail. The theoretical model is induced to simulate the measurements, showing agreement. [ABSTRACT FROM AUTHOR]

Timing and/or position-sensitive MCP detectors, which detect secondary electrons (SEs) emitted from a conversion foil during ion passage, are widely utilized in nuclear physics and nuclear astrophysics experiments. This review covers high-performance timing and/or position-sensitive MCP detectors that use SE emission for mass measurements of exotic nuclei at nuclear physics facilities, along with their applications in new measurement schemes. The design, principles, performance, and applications of these detectors with different arrangements of electromagnetic fields are summarized. To achieve high precision and accuracy in mass measurements of exotic nuclei using time-of-flight (TOF) and/or position (imaging) measurement methods, such as high-resolution beam-line magnetic-rigidity time-of-flight (B ρ -TOF) and in-ring isochronous mass spectrometry (IMS), foil-MCP detectors with high position and timing resolution have been introduced and simulated. Beyond TOF mass measurements, these new detector systems are also described for use in heavy ion beam trajectory monitoring and momentum measurements for both beam-line and in-ring applications. Additionally, the use of position-sensitive timing foil-MCP detectors for Penning trap mass spectrometers and multi-reflection time-of-flight (MR-TOF) mass spectrometers is proposed and discussed to improve efficiency and enhance precision. [ABSTRACT FROM AUTHOR]

Angle-resolved photoelectron spectrometers with microchannel plate detectors and fast digitizer electronics are versatile and powerful devices for providing non-invasive single-shot photon diagnostics at a MHz repetition rate X-ray free-electron lasers. In this contribution, we demonstrate and characterize the performance of our two operational photoelectron spectrometers for the application of hard X-rays and soft X-rays as well as new automation tools and online data analysis that enable continuous support for machine operators and instrument scientists. Customized software has been developed for the real-time monitoring of photon beam polarization and spectral distribution both in single-color and two-color operation. Hard X-ray operation imposes specific design challenges due to poor photoionization cross-sections and very high photoelectron velocities. Furthermore, recent advancements in machine learning enable resolution enhancement by training the photoelectron spectrometer together with an invasive high-resolution spectrometer, which generates a response function model. [ABSTRACT FROM AUTHOR]

Laser-plasma interactions have been demonstrated to produce bright sources of energetic radiation including ions, electrons, photons across the electro-magnetic spectrum, and neutrons. Combinations of species can significantly increase information from non-destructive imaging. Here we demonstrate single-shot co-axial radiography with both x-ray and fast-neutron radiation from a laser-driven source using a pair of gated microchannel plate photomultiplier tube channels and a fast scintillator medium. The outlined system demonstrates recovery full-width-half-maximum of (18 ± 3) ns, which is sufficient to isolate x-rays from neutrons up to (72 ± 20) MeV and could be isolated only a short distance (2 m) from the target. [ABSTRACT FROM AUTHOR]

The microchannel plate (MCP) is an electron multiplier with millions of micro through-holes that must withstand strong vibrations and enormous shocks in spaceborne detectors. To ensure the reliability and robustness of the MCP in space applications, we proposed an equivalent mechanical model of the MCP to investigate its mechanical properties, since the direct creation of the finite element model using the finite element method (FEM) is not feasible. Then, we developed a test system to verify the effectiveness of the equivalent mechanical model. The results show that the error of harmonic response analysis and the test result is less than 10 %, which is acceptable. Finally, we conducted parametric studies of the MCPs and obtained the equivalent mechanical model of the MCPs with different geometric parameters. This study will help researchers to optimize the MCP for aerospace-grade detectors. [ABSTRACT FROM AUTHOR]

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Innovative, low-loss, and compact optical systems are essential to meet the experimental requirements of emerging novel radiation sources. The microchannel plate (MCP), a metamaterial-based optical device, shows promising potential for shaping, condensing, and focusing soft x-ray radiation at synchrotron radiation (SR) facilities. This study highlights the impact of MCP optical devices on SR beam condensing capability and their sensitivity to the degree of coherence by investigating the profile of transmitted beams through single and double MCP optical devices. Transmitted diffraction patterns of soft x-ray SR radiation change with energy and radiation modes. At 92 eV, the double MCP-based device affects the beam divergence and degree of coherence more than the single MCP. Moreover, the double MCP device shows potential as a condensing optics at shorter wavelengths, i.e., 480 eV. Experiments were performed at the available end-station of the Circular Polarization beamline at the Elettra synchrotron facility in Trieste, using a high-vacuum chamber with a hexapod system, providing the precise movement necessary to align these diffractive optics. The findings contribute to the development of innovative optical systems for SR and free-electron laser beamlines, paving the way for advanced experiments in spectroscopy, microscopy, and imaging in a wide energy range. [ABSTRACT FROM AUTHOR]

The results of the study of radiation produced by the electrical explosion of Al foil with a thickness of 4 μm with an artificial periodic structure of periodic holes with 50–400 μm steps created by laser engraving are presented. The experiments were carried out on a KING pulse high-current generator (220 kA, 40 kV, 300 ns). Images of exploded foils were recorded using pinhole cameras with a 20 μm aperture on a four-frame microchannel plate camera with 5 ns temporal resolution. In experiments on the electrical explosion of thin foils, it was shown that the application of an artificial periodic structure to the foil leads to a much more uniform radiation in the UV spectrum range along the entire length and width of the foil. Uniform radiation was observed from 20 to 70 ns. It is shown that such radiation can be used for the imaging of test objects or plasma objects like exploded wires. [ABSTRACT FROM AUTHOR]

We demonstrate a simple approach to achieve three-dimensional ion momentum imaging. The method employs two complementary metal–oxide–semiconductor cameras in addition to a standard microchannel plates/phosphor screen imaging detector. The two cameras are timed to measure the decay of luminescence excited by ion hits to extract the time of flight. The achieved time resolution is better than 10 ns, which is mainly limited by camera jitters. A better than 5 ns resolution can be achieved when the jitter is suppressed. [ABSTRACT FROM AUTHOR]

Introduction. Solid-state electron multipliers (EMs) in matrix design, referred to as microchannel plates (MCPs), are an integral part of modern electronics. Recent progress in the field of molecular layering (ML) technology has offered an opportunity to tailor and improve the characteristics of solid-stated EMs by depositing thin layers inside the channels of these structures.Aim. To study the possibility of depositing thin layers inside the surface of solid-state EM channels by ML in order to increase the secondary electron emission coefficient (SEEC) of such structures, thereby improving their performance characteristics.Materials and methods. The ML method was used to deposit nanometer films of magnesium and aluminum oxides inside solid-state EM channels. The composition and structure of the layers were studied using scanning electron microscopy, X-ray photoelectron spectroscopy, secondary electron emission analysis, and atomic force microscopy.Results. Thin aluminum oxide and magnesium oxide films were synthesized inside the micron channels of solidstate EMs. The layers exhibited high uniformity along the entire length of the channels. The layer thickness varied in the range from 2 to 30 nm. Layers with improved emission and protective characteristics were obtained. Comparative tests of MCP samples containing the synthesized films were carried out.Conclusion. Good prospects for the application of emissive layers inside solid-state EM channels were shown. Structures with a high aspect ratio are promising objects for ML application. The creation of nanocomposite structures based on MCPs opens up the fundamental possibility of improving the current technology of producing electrooptic materials and devices. The MCP structures containing aluminum oxide layers obtained by ML technology were experimentally tested to detect beam collisions (FBBC) for work in detectors at the NICA accelerator complex. Following deposition of a 3.0 nm-thick Al2O3 film in the channels of the tested MCP samples, the signal amplitude increased by 1.5 times. The deposition of layers with a film thickness of 10 nm resulted in a 2.5-fold increase in the amplitude.

The Super Tau Charm Facility (STCF) is a state-of-the-art electron-positron collider operating in the center-of-mass energy range of 2–7GeV and achieving a peak luminosity of more than 0.5×1035cm−2s−1, which is pivotal for advancing particle physics research. The DIRC-like time-of-flight (DTOF) detector is one of the crucial components of the STCF, designed to identify high-momentum charged particles with high precision. A significant element of the DTOF is the microchannel plate photomultiplier tube (MCP-PMT), known for its exceptional time resolution in the detection of Cherenkov light. With the STCF expected to operate for over a decade, stringent requirements are imposed on the MCP-PMT, requiring an integrated anode charge (IAC) in excess of 10C/cm2. In this paper, the lifetime of the single anode MCP-PMT prototypes is investigated and a multi-anode MCP-PMT design is presented. The results show that the lifetime of the single anode MCP-PMT is greater than 11C/cm2 when a 6 nm-thick ALD layer is deposited on the inner surface of the MCP and an electron scrubbing dosage of 0.75μA⋅h/cm2 is applied to the MCP. The lifetime is expected to be further improved by increasing the electron scrubbing dosage and optimizing the ALD layer. The studies on the single anode MCP-PMTs will be applied to the development of the long-life multi-anode MCP-PMT. [ABSTRACT FROM AUTHOR]

We study the possibility of application of the methods of laser Doppler anemometry for the noncontact measurement of the velocity of moving media in various phase states. We mention the specific features of the conditions of application of laser Doppler anemometers and, in particular the fact that, in numerous cases there exist restrictions on the use of photomultipliers. With an aim to find an alternative to the classical photomultiplier of a laser Doppler anemometer, we study three types of photomultipliers: classical electric vacuum photomultipliers, silicon avalanche multipixel photomultipliers, and photomultipliers with microchannel plate. We performed physical experiments aimed at measuring the velocity of aero- and hydrodynamic flows by laser Doppler anemometers with photomultipliers of the indicated three types. Actually, we measured the velocities of a rotating glass disk, of an aerodynamic flow in a channel with rectangular cross section, of an aerosol flow, and of a flooded hydrodynamic jet. The accumulated experimental data are analyzed according to the criteria of evaluation of the quality (efficiency) of operation and the ranges of applicability of the specified photomultipliers. By analyzing the physical properties of the investigated photomultipliers, we clarify their efficiency characteristics in different experiments. The ranges of efficient applications of these photomultipliers are determined for a broad class of physical experiments. The obtained results are of high importance for the researchers involved in the study of aero- and hydrodynamic flows in which it is necessary to have accurate and reliable result of measurements of the flow velocity. The optimal choice of a photomultiplier for the laser anemometers makes it possible to increase the accuracy, simplify the procedure of collecting the experimental data, and to reduce the cost of the final equipment. [ABSTRACT FROM AUTHOR]

The Pohang Accelerator Laboratory X‐ray Free‐Electron Laser (PAL‐XFEL) operates hard X‐ray and soft X‐ray beamlines for conducting scientific experiments providing intense ultrashort X‐ray pulses based on the self‐amplified spontaneous emission (SASE) process. The X‐ray free‐electron laser is characterized by strong pulse‐to‐pulse fluctuations resulting from the SASE process. Therefore, online photon diagnostics are very important for rigorous measurements. The concept of photo‐absorption and emission using solid materials is seldom considered in soft X‐ray beamline diagnostics. Instead, gas monitoring detectors, which utilize the photo‐ionization of noble gas, are employed for monitoring the beam intensity. To track the beam position at the soft X‐ray beamline in addition to those intensity monitors, an X‐ray ionization beam position monitor (XIBPM) has been developed and characterized at the soft X‐ray beamline of PAL‐XFEL. The XIBPM utilizes ionization of either the residual gas in an ultra‐high‐vacuum environment or injected krypton gas, along with a microchannel plate with phosphor. The XIBPM was tested separately for monitoring horizontal and vertical beam positions, confirming the feasibility of tracking relative changes in beam position both on average and down to single‐shot measurements. This paper presents the basic structure and test results of the newly developed non‐invasive XIBPM. [ABSTRACT FROM AUTHOR]

The reversible bonding of microfluidic chips has been developing rapidly with the requirement of reusable microfluidic devices or the need to obtain the samples inside the chip. Traditional bonding methods for polymer‐based microfluidics, e.g., thermal bonding, permanently attach the substrate and cover plate. Sometimes, once the chip flow channel is blocked, it is difficult to clean and affect the reusability of the chip. This study proposes a new reversible bonding method for poly (methyl methacrylate) (PMMA) microfluidic chips with the help of stretch release adhesive strips. The designed microchannels were fabricated on the surface of PMMA plates using CO2 laser irradiation. Then, stretch release adhesive strips were used as an intermediate layer between the substrate (with microchannels) and another flat PMMA/PS/PC plate to seal the microchannel. The assembled chip sets were bonded at room temperature with bonding strength comparable with other permanent bonding methods. Experimental results show that simply pulling the adhesive layer by applying a shear force can easily detach the intermediate adhesive layer from both the substrate and cover plate to separate the bonded chipset. The proposed reversible bonding method is simple, rapid and has low residue and high bonding strength. Bacterial culture experiments were also conducted to verify the biocompatibility of the proposed bonding method. The proposed reversible bonding technique can be used for polymer‐based microfluidic devices that require sample recovery or chip reuse. Highlights: The stretch release adhesive strip can provide high bond strength.It allows easy peeling for reversible bonding.It bonds at room temperature with simple operation.It has good transparency for easy observation of experiments.It has good biocompatibility. [ABSTRACT FROM AUTHOR]

This document discusses the optimization of operating conditions for battery thermal management systems (BTMS) in electric vehicles. The operational temperature of lithium-ion batteries has a significant impact on their efficiency and safety. The ideal temperature range for efficient operation is 20-40 °C, with a recommended temperature difference between batteries of no more than 5 °C. Researchers have explored various methods to regulate battery temperature, including using phase change materials (PCM) and heat dissipation techniques. These studies aim to improve battery performance in both low and high-temperature environments and prevent thermal runaway. The findings from these studies can contribute to the development of more efficient BTMS for lithium batteries. [Extracted from the article]

Transmission-mode (t-mode) GaAs negative electron affinity photocathodes (NEA-PCs) can be integrated with the optical focusing lenses and microchannel plates to produce high-quality electron beams and high-sensitive detectors. Quantum efficiency (QE) of ∼40% has been reported for the t-mode thick (>1000 nm) GaAs NEA-PCs. Nevertheless, practical applications of these devices have been seriously restricted by their long response time (tens of picoseconds). In this work, the all-dielectric meta-surfaces (ADMS) were designed as the light managers for the t-mode ultra-thin GaAs NEA-PCs. For the 500–850 nm waveband, high light absorption (>80%) can be obtained through coupling the electromagnetic dipole moments of ADMS into the leaky optical modes in 100 nm ultra-thin GaAs NEA-PC layer, which leads to enhanced QE higher than that of the thick ones, the response time less than 5 ps, and the mean transverse energy less than 60 meV, respectively. Given these properties, ADMS t-model ultra-thin NEA-PCs represent a promising photocathode to provide the high-brightness short-pulse spin-polarized electron beams and high-sensitive fast-response detectors for the electron accelerator and low-light-level photodetection applications, respectively. [ABSTRACT FROM AUTHOR]

The uniformity of flow distribution within the evaporative cooling plate is essential for its heat transfer performance, given its role as the core component in the pump--driven two-phase flow cooling system. Nevertheless, traditional technical methods employed to achieve uniform flow distribution, such as using an external head and an internal large-diameter sump, lead to a cold plate with excessive volume and weight, rendering it unsuitable for numerous engineering applications. In response to these challenges, this paper introduces a novel flow distribution structure that integrates a spoiler column with a sump. Numerical simulation is utilized to examine the flow distribution characteristics of this structure. The study examines the influence of factors, including the inlet and outlet positions, sump width, and spoiler column distribution, on the flow distribution characteristics. The findings suggest that, for micro-channel cold plates, achieving a more uniform flow distribution is possible by positioning the inlet and outlet closer to the center of the sump. An increase in the sump width proves effective in reducing the non-uniformity of the flow distribution. Furthermore, the addition of a spoiler column at both the inlet and outlet positions results in a significant reduction in non-uniformity. Alternatively, adding a spoiler column at the inlet alone can also yield positive results. Overall, among the eight working conditions analyzed in this paper, the cold plate exhibits a maximum reduction of 80% in overall flow distribution non-uniformity. [ABSTRACT FROM AUTHOR]

Formulas are given for calculating the coefficient of backscattered electrons depending on the material (atomic number Z), i.e., the chemical composition of a sample, and the energy EB of the primary irradiating electrons. The calculation of the detectable signal of reflected electrons is given depending on Z, EB, and the response function F of semiconductor detectors and detectors based on microchannel plates (MCPs). The calculation results are compared with the experimentally measured ones. A comparative analysis of the contrast of images of the composition of samples obtained for different types of detectors at different EB is performed. The results of the research are intended to serve practical users and experimenters in scanning electron microscopy. [ABSTRACT FROM AUTHOR]

We present results from x-ray imaging of high-aspect-ratio magnetic reconnection experiments driven at the National Ignition Facility. Two parallel, self-magnetized, elongated laser-driven plumes are produced by tiling 40 laser beams. A magnetic reconnection layer is formed by the collision of the plumes. A gated x-ray framing pinhole camera with micro-channel plate detector produces multiple images through various filters of the formation and evolution of both the plumes and current sheet. As the diagnostic integrates plasma self-emission along the line of sight, two-dimensional electron temperature maps ⟨ T e ⟩ Y are constructed by taking the ratio of intensity of these images obtained with different filters. The plumes have a characteristic temperature ⟨ T e ⟩ Y = 240 ± 20 eV at 2 ns after the initial laser irradiation and exhibit a slow cooling up to 4 ns. The reconnection layer forms at 3 ns with a temperature ⟨ T e ⟩ Y = 280 ± 50 eV as the result of the collision of the plumes. The error bars of the plumes and current sheet temperatures separate at 4 ns, showing the heating of the current sheet from colder inflows. Using a semi-analytical model, we survey various heating mechanisms in the current sheet. We find that reconnection energy conversion would dominate at low density ( n e ≲ 7 × 10 18 cm−3) and electron-ion collisional drag at high-density (≳ 10 19 cm−3). [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells are a prime choice for substitute electricity producers. Membrane electrode assembly (MEA), bipolar electrodes, and current collectors belong to only a limited number of primary parts of the proton exchange membrane fuel cell (PEMFC). Bipolar plates are among the most famous elements in the fuel cell; they are responsible for the electrochemical reaction, as well as the flow of gases from one bipolar plate to another. A bipolar plate is to be a good electro-conducting, non-corrosive, and a high mechanical strength product. The attainability of the specification is achieved by graphite and metallic materials, each one having its own merits and demerits that are discussed in this article. Likewise, making the second pass for the flow pattern is equally important for the cell to have good performance and efficiency. The emergence of innovative and new bipolar plate designs has caused the achievement of high performance of these plates. The present review article principally focuses on the experimental study of diverse flow fields in the design of PEMFC and on the influence of various geometrical properties on the general operation of fuel cells made of PEMFC, and also on the manufacturing procedure utilized for building contemporary fuel cells. [ABSTRACT FROM AUTHOR]

The article presents a method for one-sided etching of channel openings in unetched microchannel plate blanks using dilute hydrofluoric acid. In this work, we used the blanks of MCP 18-10 microchannel plates. The treatment was carried out in 0.2 N hydrofluoric acid solution at room temperature without oscillating or stirring the solution. Following etching, the diameter of channel openings increased by over 10% of the diameter of MCP 18-10 channels, which increased the electron transmission of the device. [ABSTRACT FROM AUTHOR]

The Lunar Environment heliospheric X-ray Imager (LEXI) is a wide field-of-view soft X-ray telescope developed to study solar wind-magnetosphere coupling. LEXI is part of the Blue Ghost 1 mission comprised of 10 payloads to be deployed on the lunar surface. LEXI monitors the dayside magnetopause position and shape as a function of time by observing soft X-rays (0.1–2 keV) emitted from solar wind charge-exchange between exospheric neutrals and high charge-state solar wind plasma in the dayside magnetosheath. Measurements of the shape and position of the magnetopause are used to test temporal models of meso- and macro-scale magnetic reconnection. To image the boundary, LEXI employs lobster-eye optics to focus X-rays to a microchannel plate detector with a 9.1 × ∘ 9.1 ∘ field of view. [ABSTRACT FROM AUTHOR]

The Spectroscopic Investigation of Nebular Gas (SING) is a near-ultraviolet (NUV) low-resolution spectrograph payload designed to operate in the NUV range, 1400 Å – 2700 Å, from a stable space platform. SING telescope has a primary aperture of 298 mm, feeding the light to the long-slit UV spectrograph. SING has a field of view (FOV) of 1 ∘ , achieving a spatial resolution of 1.33 arcminute and spectral resolution of 3.7 Å( R ∼ 600 ) at the central wavelength. SING employs a micro-channel plate (MCP) with a CMOS readout-based photon-counting detector. The instrument is designed to observe diffuse sources such as nebulae, supernova remnants, and the interstellar medium (ISM) to understand their chemistry. SING was selected by the United Nations Office for Outer Space Affairs to be hosted on the Chinese Space Station. The instrument will undergo qualification tests as per the launch requirements. In this paper, we describe the hardware design, optomechanical assembly, and calibration of the instrument. [ABSTRACT FROM AUTHOR]

A method for measuring the resistive characteristics of channels in the blanks of microchannel plates was developed. Two probes were used for measurements, which minimized leakage currents through adjacent channels. The resistive properties of single channels of the microchannel insert in the reduced blank of MCP 18-10 were studied. It was established that the resistance of the channels depends on their position in the microchannel honeycomb. It was shown that the channels located in close proximity to the monolithic frame have less resistance compared to those located in the middle of a multicore glass honeycomb. [ABSTRACT FROM AUTHOR]

Timing and/or position-sensitive MCP detectors, which detect secondary electrons (SEs) emitted from a conversion foil during ion passage, are widely utilized in nuclear physics and nuclear astrophysics experiments. This review covers high-performance timing and/or position-sensitive MCP detectors that use SE emission for mass measurements of exotic nuclei at nuclear physics facilities, along with their applications in new measurement schemes. The design, principles, performance, and applications of these detectors with different arrangements of electromagnetic fields are summarized. To achieve high precision and accuracy in mass measurements of exotic nuclei using time-of-flight (TOF) and/or position (imaging) measurement methods, such as high-resolution beam-line magnetic-rigidity time-of-flight (Bρ-TOF) and in-ring isochronous mass spectrometry (IMS), foil-MCP detectors with high position and timing resolution have been introduced and simulated. Beyond TOF mass measurements, these new detector systems are also described for use in heavy ion beam trajectory monitoring and momentum measurements for both beam-line and in-ring applications. Additionally, the use of position-sensitive timing foil-MCP detectors for Penning trap mass spectrometers and multi-reflection time-of-flight (MR-TOF) mass spectrometers is proposed and discussed to improve efficiency and enhance precision.

For the first time, details of the spatial and temporal acceptable evolution of the merging process of co-rotating electron vortices in a potential well are successfully captured using a "single-shot method" with a high temporal resolution of 10 µs. Four-electron filaments are trapped inside the Beam eXperiment-Upgrade linear trap [H. Himura, Nucl. Instrum. Methods Phys. Res. A 811, 100 (2016)] with a uniform axial magnetic field and co-axial multi-ring electrodes. Images of non-emitting electron filaments are captured using a high-speed camera with up to 1 000 000 fps, a microchannel plate, a fast-decay phosphor screen of which fluorescence duration is 0.15 µs, and a super fine metallic mesh with an open area ratio of 89%. Images captured every 10 µs clearly show the growth of multiple short-wave instabilities in the wing trailing electron vortices. The experimental methods and measurement techniques presented in this paper can contribute to revealing exactly how small vortices evolve into a large structure or turbulence in a potential well through complex processes. [ABSTRACT FROM AUTHOR]

This paper presents the results of measurements of fission fragments using a time-of-flight system with a position-sensitive detector based on microchannel plates designed to measure the masses of nuclear reaction products at the MAVR facility. The advantage of such MCPs is their high positional sensitivity and high efficiency of registration of heavy charged particles with low energy. The paper presents a technical description of the fission fragments registration system and the results of measuring the parameters of a position-sensitive detector based on large-area microchannel plates (40 × 60 mm2) obtained by measuring 252Cf spontaneous fission fragments. The coordinate resolution along the X and Y axes was determined when fission fragments were registered in the 14N+192Au reaction at the MAVR installation. The time resolution of the PSD was obtained by registering the time of flight of alpha particles emitted by the radioactive source 226Ra. [ABSTRACT FROM AUTHOR]

The EOF of a viscoelastic Maxwell fluid driven by an alternating pressure gradient and electric field in a parallel plate microchannel with sinusoidal roughness has been investigated within the Debye–Hückel approximation based on boundary perturbation expansion and separation of variables. Perturbation solutions were obtained for the potential distribution, the velocity and the mean velocity, and the relation between the mean velocity and the roughness. There are significant differences in the velocity amplitudes of the Newtonian and Maxwell fluids. It is shown here that the velocity distribution of the viscoelastic fluid is significantly affected by the roughness of the walls, which leads to the appearance of fluctuations in the fluid. Also, the velocity is strongly dependent on the phase difference θ of the roughness of the upper and lower plates. As the oscillation Reynolds number ReΩ increases, the velocity profile and the average velocity um(t) of AC EOF oscillate rapidly but the velocity amplitude decreases. The Deborah number De plays a similar role to ReΩ, which makes the AC EOF velocity profile more likely to oscillate. Meanwhile, phase lag χ (representing the phase difference between the electric field and the mean velocity) decreases when G and θ are increased. However, for larger λ (e.g., λ > 3), it almost has no phase lag χ. [ABSTRACT FROM AUTHOR]

Measurements from particle timing detectors are often affected by the time walk effect caused by statistical fluctuations in the charge deposited by passing particles. The constant fraction discriminator (CFD) algorithm is frequently used to mitigate this effect both in test setups and in running experiments, such as the CMS-PPS system at the CERN's LHC. The CFD is simple and effective but does not leverage all voltage samples in a time series. Its performance could be enhanced with deep neural networks, which are commonly used for time series analysis, including computing the particle arrival time. We evaluated various neural network architectures using data acquired at the test beam facility in the DESY-II synchrotron, where a precise MCP (MicroChannel Plate) detector was installed in addition to PPS diamond timing detectors. MCP measurements were used as a reference to train the networks and compare the results with the standard CFD method. Ultimately, we improved the timing precision by 8% to 23%, depending on the detector's readout channel. The best results were obtained using a UNet-based model, which outperformed classical convolutional networks and the multilayer perceptron. [ABSTRACT FROM AUTHOR]

In recent times, the field of nanotechnology has been instrumental in driving significant breakthroughs in heat transport. These technological breakthroughs have shown their significance in improving the efficiency of heat exchangers, such as thermal pipes, microfluidic structures, and electronic components that depend on effective heat transfer processes. This study aims to explore innovative methods for enhancing heat transfer effectiveness. The present investigation focuses on the two-dimensional, incompressible, electrically conducting ternary liquid flow between two parallel porous plates in a microchannel. This has been considered with the convective boundary conditions employing the thermophoretic particle deposition phenomena. The numerical results of the mathematical, physical problem entailed a similar solution employed with the RKF-45 method. The stimulus of these process-sensitive non-dimensional parameters has been discussed and presented graphically with validation of the published results. The velocity profiles decline as increment in S 1 and M F whereas the thermal profile lessens with the augmentation in Biot numbers Bi 1 and Bi 2 . Moreover, the study emphasizes that the mass and thermal energy distribution rates exhibit a reduction when the solid volume percentage, thermophoretic constraints, and the existence of a porous medium increase. The ramifications of these discoveries are significant in terms of the design and optimization of microfluidic devices and thermal exchangers. The findings are visually shown using illustrations, offering valuable insights into the intricate relationships among the variables under investigation. [ABSTRACT FROM AUTHOR]

Plate and frame heat exchangers are widely used nowadays, because their designed corrugations result in reducing the liquid turbulence to the counter current liquid flow and increasing heat transfer efficiency. In this manuscript, the effect of nanofin array coatings on the plates of a micro-channel heat exchanger with cross-flow configuration on overall heat transfer coefficient U-Value was studied. Six copper corrugated plates were installed in a micro-channel plate and frame heat exchanger. Nanofin arrays were synthesized by electrodeposition method. The dendritic copper nanofin array grew on the copper plates from electrolyte solution along with applying an increasing current in a specified time. The morphology of coatings on the plate surface was examined by SEM, and AFM technique. The cold and hot water with a predetermined inlet temperature for both hot and cold side circulated in the microchannel and U-Value was measured thereupon, the measured temperature difference was between 1.9 and 4.8 °C showing an increase of 41–135% in the U-Value compared to the non-coated versions of the plates. [ABSTRACT FROM AUTHOR]

The results of calculations of electric fields, potentials, and trajectories of photoelectrons calculations of single-channel dual-spectral thermal imager, implemented in the IIT architecture are presented. The values of the optimal potentials on the control electrodes (microchannel plate, reading electrode, and photocathode) that form a picture of the images of objects and ensure the correct reading of the potential relief from the surface of the sensor-converter pyroelectric film of the image thermal receiver under discussion are determined. [ABSTRACT FROM AUTHOR]

Abstract—A specialized isotope mass spectrometer for determining the isotopic ratio of lithium by ERIAD (electrospray with atomization in an ion source) is described. The device uses a Matthauch–Herzog-type mass analyzer with double focusing to use ion beams with a large spread in energy and simultaneous registration of signals of both lithium isotopes (6Li and 7Li), and a two-channel receiver based on a doublet of microchannel plates. The gas-dynamic interface is built according to the Kontorowitz–Gray scheme; from the gas-dynamic point of view, it is "Jong", that is, the distance between the nozzle and the skimmer is 4 times the size of the "Mach barrel" at the operating pressure (200 Pa). The device is desktop, its weight does not exceed 20 kg. The measurement time is 1000 s, sample replacement time is 100 s, measurement accuracy is ~0.1%. [ABSTRACT FROM AUTHOR]

Estimating the impact parameter in a single high-energy ion collision event is an important problem in data analysis in particle physics, because knowledge of the impact parameter is crucial for extracting information about the properties of nuclear matter. In this study, we present the use of a neural network approach for estimating the impact parameter and determining the collision class (head-on or peripheral collisions). We have modeled the data sourced from microchannel plate detectors in two geometries based on the collision dataset at energies GeV obtained by the QGSM MC event generator. We utilized the spatial distribution of particles and their time-of-flight data as event features. The addition of time-of-flight information improves the quality of impact parameter estimation. By comparing two detector geometries with different pseudorapidity acceptances ( and ), we demonstrated that a wider interval significantly enhances the results. The proposed algorithm was able to successfully classify more than 98 of head-on collision events with an impact parameter of less than 5 fm and can be further useful as a fast trigger system. We also discuss further developments and improvements for possible applications of this technique in future experimental setups. [ABSTRACT FROM AUTHOR]

20-inch Large area photomultiplier tube based on microchannel plate (MCP-PMT) is newly developed in China. It is widely used in high energy detection experiments such as Jiangmen Underground Neutrino Observatory (JUNO), China JinPing underground Laboratory (CJPL) and Large High Altitude Air Shower Observatory (LHAASO). To overcome the poor time performance of the existing MCP-PMT, a new design of large area MCP-PMT is proposed in this paper. Three-dimensional models are developed in CST Studio Suite to validate its feasibility. Effects of the size and bias voltage of the focusing electrodes and MCP configuration on the collection efficiency (CE) and time performance are studied in detail using the finite integral technique and Monte Carlo method. Based on the simulation results, the optimized operating and geometry parameters are chosen. Results show that the mean ratio of photoelectrons landing on the MCP active area is 97.5%. The acceptance fraction of the impinging photoelectrons is close to 100% due to the emission of multiple secondary electrons when hitting the MCP top surface. The mean transit time spread (TTS) of the photoelectrons from the photocathode is 1.48 ns. [ABSTRACT FROM AUTHOR]

The focusing electrode plays an important role to reduce the electron beam trajectory with low dispersion and high brightness. This article summarizes the importance of the vertically aligned multi-walled carbon nanotube effect with the focusing electrode. First of all, the effect of electron beam trajectory is studied with the different heights, hole sizes, and applied voltage of the focusing electrode by the opera 3D simulation. The field emission electron beam spot is captured in the microchannel plate which helps to reduce the signal noise effect and damage of CNT tips by the joule heating effect. The high-dense bright spot is optimized at the focusing electrode hole size of 2 mm, and the height of 1 mm from the gate mesh electrode at the low bias voltage of − 200 V without the loss of current. The FWHM of the electron beam is calculated 0.9 mm with its opening angle of 0.9° which could be applicable in high-resolution multi-electron beam microscopy and nano-focused X-ray system technology. [ABSTRACT FROM AUTHOR]

This work is devoted to the development of a method for the reconstruction of plasma extreme UV (EUV) spectra recorded by a three frame grazing incidence spectrograph (GIS-3D). The spectrograph provides registration of radiation reflected from the diffraction grating (DG) on a three-frame detector based on a microchannel plate with a scintillator screen and registration on a CCD camera, with an exposure time of one frame of ∼1.5 ns. DG has a gold-coated spherical concave form with a radius of curvature of 2 m and dimensions of 30 × 40 × 10 mm3. In this case, radiation is incident on the DG at a grazing angle of 2°; the DG period is 1.66 µm. The new single-pass method for the reconstruction of plasma EUV spectra was developed, which solves the inverse problem of decomposing experimental signals into separate contributions from each of the diffraction orders, followed by the reconstruction of the true plasma spectrum. Using the developed method, the possibility of finding a close approximation to the shape of a DG groove profile based on a priori information about the recorded spectra was demonstrated. In order to test and demonstrate the efficiency of this method, several experimental EUV spectra obtained at the Z-pinch facility Angara-5-1 with a current of ∼3–4 MA through loads made of either tungsten wires or polypropylene fibers were reconstructed. In addition, to test the single-pass method, the transmittance of EUV in cold aluminum was measured in the wavelength range of 3–35 nm, and it has a good match with the Henke database. [ABSTRACT FROM AUTHOR]

Microchannel plate (MCP) photomultiplier tubes (PMTs) are frequently used in experimental diagnostics, where they are operated in single-pulse current measurement mode. However, considering the significant amplitude fluctuations in the measured signal, the resulting output signal from the MCP-PMT is inevitably distorted by gain saturation. Therefore, understanding the correlation between the MCP-PMT output signal and gain saturation is critical in assessing the extent of output signal distortion and determining the MCP-PMT saturation level. This knowledge allows for a more precise assessment of the input signal's features. In this paper, we present an experimental method for restoring the initial waveform from the saturated MCP-PMT signal. To correct the amplitude-drop caused by gain saturation, our technique involves calibrating the MCP-PMT's relative gain as a function of the accumulated output charge using a square-wave light source. We then applied this approach to restore a ∼500 ns saturated pulse from a double-layer 10 mm diameter MCP-PMT. The restored signal showed a deviation of less than 6% from the reference waveform, which validates the effectiveness of the technique. [ABSTRACT FROM AUTHOR]

Evaluation of the impact parameter in a single event of relativistic heavy ion collision is crucial for correct and efficient data processing and analysis. In this work we have studied the possibility of estimating the impact parameter in heavy ion collisions by using artificial neural networks applied to the charged particle data from fast microchannel plate (MCP) detectors. Charged particles' multiplicity, their spatial distribution and time-of-flight data were used as event features to be analyzed by the artificial neural network algorithms. We investigated two different configurations of microchannel plate detector layout, that have different data and computational requirements. We have shown that the developed artificial neural networks technique is capable of providing sufficiently good and fast results on the impact parameter determination in a single heavy ion collision event for both configurations of MCP detectors layout. In our first exercises, the proposed algorithm has successfully identified more than 90 of Au Au collision events with the impact parameter less than 5 fm or less than 1 fm, which suggests its use as a fast trigger. [ABSTRACT FROM AUTHOR]

A compact online proton spectrometer based on a CMOS plate detector was proposed for the diagnosis of picosecond intense-laser accelerated protons. Inside the CMOS plate detector, a composite structure that composed of a scintillator screen, a fiber optic plate (FOP), and a CMOS sensor was designed to detect the protons safely and efficiently. The scintillator screen converted the incident protons to visible light, which, in turn, was collected by using the FOP and detected by using the CMOS sensor. An additional aluminum housing was designed to decrease the strong electromagnetic pulse (EMP) impact on the electronic readout system from picosecond laser–plasma interaction. This online spectrometer is compact and cost-effective than the system based on the micro-channel plate or scintillator screen in combination with an electron multiplying CCD camera and has better resistance to radiation damage than the system based on a single CMOS sensor. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid manufacturing process for the preparation of complex cavity structure parts with high surface quality. Firstly, laser precision packaging technology is utilized to accurately connect a thin plate to a substrate with microchannel. Secondly, Direct Metal Laser-Sintering (DMLS) technology is utilized to completely shape the part. The morphology and microstructure of laser encapsulated specimens and DMLS molded parts were investigated. The results show that the thin plate and the substrate can form a good metallurgical bond. The lowest surface roughness of the DMLS molded parts was 1.18 μm. The perpendicularity between the top of the microchannel and the side wall was optimal when the laser power was 240 W. Consequently, the hybrid manufacturing process effectively solves the problems of poor surface quality and powder sticking of closed inner cavities. The method effectively eliminates the defects of adhesive powder in the inner cavity of the DMLS microchannel, improves the finish, and solves the problem that mechanical tools cannot be processed inside the microchannel, which lays the foundation for the research of DMLS high-quality microchannel process. [ABSTRACT FROM AUTHOR]

In order to replace the phosphor screen of a proximity-gated x-ray framing camera with a readout circuit using a time-interleaved structure, this paper carries out the design of a high-isolation RF switch. In this paper, a Metal-Oxide-Semiconductor Field Effect Tube (MOSFET) switching circuit is designed to achieve high isolation and low insertion loss at 0.5–3 GHz. This solves the problem that the switching circuit cannot be turned off properly due to the parasitic capacitance of MOSFETs in the process of RF signal transmission, resulting in signal feedthrough. It also ensures that the input signal can be transmitted to the output intact when the switching circuit is turned on. High isolation is achieved by using parallel resonance to increase the voltage division and series resonance to leak the current. The switch achieves 76 dB isolation and 0.07 dB insertion loss at 1 GHz frequency. Isolation is increased by adding parallel branches near the 2 and 3 GHz frequency points, achieving greater than 33 dB isolation from 0.5 to 3 GHz. [ABSTRACT FROM AUTHOR]

Detectors with microchannel plates (MCPs) provide unique capabilities to detect single photons with high spatial (

The document is an erratum for a scientific paper titled "Radiation, optical, power flow, and electrical diagnostics at the Z facility." It includes corrections to figure captions and an acknowledgment section that recognizes the contributions of individuals from various laboratories in the conception and design of several diagnostics. The authors express gratitude to editors, reviewers, and employees from Lawrence Livermore National Laboratory, Sandia National Laboratories, Los Alamos National Laboratory, and other institutions for their contributions to the research. The document also mentions the management and operation of Sandia National Laboratories by National Technology and Engineering Solutions of Sandia LLC, a subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration. [Extracted from the article]

The electronic work function, w(e−), and the ionic work function, w(Li+), of a lithium ultraphosphate, Li0.67PO2.8, have been measured by thermionic emission in the Richardson–Dushman regime. The values derived are w(Li+) = 1.99 ± 0.18 eV and w(e−) = 2.64 ± 0.38 eV. The measurements have been made possible by the implementation of a micro-channel plate detector, allowing the counting of single charge carrier particles, equivalent to a detection limit on the order of 1 aA. The ionic work function is demonstrated to increase with increasing lithium content in a series of lithium phosphates. [ABSTRACT FROM AUTHOR]

Microchannel plates (MCPs) are widely utilized as key device components in various photomultipliers; however, the performance of MCPs cannot be further improved by traditional processing. Atomic layer deposition (ALD) is a promising route to prepare a composite conductive layer and secondary electron emission (SEE) layer structure on the inner wall of the MCP. Moreover, ZnO is an essential component of a composite conductive layer, which is located at the bottom of the SEE layer and significantly influences the SEE coefficient, which, in turn, affects the gain performance of MCPs. Herein, ALD is used to deposit different thicknesses of ZnO films (1–50 nm) on an Si substrate, resulting in an ZnO/Si double-layer film structure. The relationship between the SEE coefficient and the primary electron energy of ZnO films with different thicknesses was established. The maximum secondary electron yield value of 2.04 is achieved at a film thickness of 30 nm. Moreover, Dionne's SEE model and theory of semiconductors are used to simulate and verify the experimental results. These results provide useful guidelines for the development of ALD-MCPs. [ABSTRACT FROM AUTHOR]

The battery thermal management system (BTMS) for lithium-ion batteries can provide proper operation conditions by implementing metal cold plates containing channels on both sides of the battery cell, making it a more effective cooling system. The efficient design of channels can improve thermal performance without any excessive energy consumption. In addition, utilizing phase change material (PCM) as a passive cooling system enhances BTMS performance, which led to a hybrid cooling system. In this study, a novel design of a microchannel distribution path where each microchannel branched into two channels 40 mm before the outlet port to increase thermal contact between the battery cell and microchannels is proposed. In addition, a hybrid cooling system integrated with PCM in the critical zone of the battery cell is designed. Numerical investigation was performed under a 5C discharge rate, three environmental conditions, and a specific range of inlet velocity (0.1 m/s to 1 m/s). Results revealed that a branched microchannel can effectively improve thermal contact between the battery cell and microchannel in a hot area of the battery cell around the outlet port of channels. The designed cooling system reduces the maximum temperature of the battery cell by 2.43 °C, while temperature difference reduces by 5.22 °C compared to the straight microchannel. Furthermore, adding PCM led to more uniform temperature distribution inside battery cell without extra energy consumption. [ABSTRACT FROM AUTHOR]

We conducted developmental experiments using avalanche photodiode (APD) for electron measurements applicable in future space plasma explorations. Electrons with energies of 10 eV to a hundred keV could be detected by applying "floating" voltages up to +5 kV to APD to achieve wide‐energy electron measurements. We detected 10‐eV electrons from an electron source as energized electrons of an energy of approximately 5 (5.01) keV due to the 5‐keV electrostatic acceleration (=Source energy: 0.01 keV + Acceleration energy: 5 keV; hereafter, (0.01 + 5) keV) with an energy resolution of ∼4.6 keV by simplified assumption and calculation based on peak energy and full width at half maximum of the pulse height distribution. The energy resolution for (5 + 0)‐keV electrons, ∼5.3 keV in our experiments, was equivalent to the previous results. On the other hand, we concluded that for (5 + 5) keV, the energy resolution was significantly improved to 1.3 keV compared with that for (5 + 0) keV. For (1 + 5)‐keV electrons, the energy distribution showed a broadening toward lower energies than that for (6 + 0) keV because the backscattered electrons produced secondary electrons at the APD chassis surface, which were accelerated to 5 keV by the floating voltage to be detected by the APD. We verified that the floating‐mode APD can contribute to space plasma measurements as a detector with characteristics different from those of microchannel plates. This is the first achievement to establish advanced in‐situ observation techniques based on APD for wide‐energy (a few eV to a hundred keV) electron measurements in space. Key Points: We conducted fundamental developments of floating‐mode avalanche photodiode (APD) for reducing lowermost measurable energy of electrons in spaceExperimental results indicate that the floating‐mode APD applied by +5 kV as floating voltage can detect 10‐eV electronsWe identified contaminations by secondary electrons that were produced by backscattered electrons and accelerated by the floating voltage [ABSTRACT FROM AUTHOR]