- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Spectroscopic DEPFETs at high frame rates using window mode
摘要： An active pixel sensor like an array of DEPFET (DEpleted P-channel Field Effect Transistor) pixels allows for very flexible operation modes and an adaptability of the sensor design to the specific needs of the scientific instrument objectives. For a very high time resolution at the order of one microsecond, a full parallel readout of all pixels is required. Every readout node needs to be connected to readout electronics separately. Furthermore, to preserve a good spectroscopic performance, the integration of a storage functionality into each pixel prevents the influence of events occurring during the readout process and provoking an incorrect energy information. The energy of such events is detected incorrectly and is not falsifiable with a subsequent analysis. An active pixel sensor based on a DEPFET with internal storage and wired for full parallel readout is in production and will be available for testing in the future. Alternatively, the ability of an active pixel sensor to be read out in window (region-of-interest readout) mode allows for the investigation of the behavior at high frame rates at the order of 100 kHz for DEPFET devices with and without storage functionality.
关键词： Imaging spectroscopy,Solid state detectors,X-ray detectors and telescopes
更新于2025-09-23 15:23:52
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A two-tier monolithically stacked CMOS Active Pixel Sensor to measure charged particle direction
摘要： In this work we present an innovative approach to particle tracking based on CMOS Active Pixel Sensors (APS) layers, monolithically integrated in an all-in-one chip featuring multiple, stacked, fully functional detector layers capable to provide momentum measurement (particle direction) within a single detector by using multiple layer impact point coordinates. The whole system will results in a very low material detector, since each layer can be thinned down to tens of micrometres, thus dramatically reducing multiple scattering issues. To build such a detector, we rely on the capabilities of the CMOS vertical scale integration (3D-IC) 130 nm Chartered/Tezzaron technology, used to integrate two fully-functional CMOS APS matrix detectors, including both sensing area and control/signal elaboration circuitry, stacked in a monolithic device by means of Through Silicon Via (TSV) connections. Such a detector would allow accurate estimation of the impact point of an ionizing particle and of its incidence angle. Two batches of the first chip prototype have been produced and characterized using particle beams (e.g. protons) demonstrating the suitability of particle direction measurement with a single, multiple layers, 3D vertically stacked APS CMOS detector.
关键词： Particle tracking detectors (Solid-state detectors),VLSI circuits
更新于2025-09-23 15:23:52
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The LXe calorimeter and the pixelated timing counter in the MEG II experiment
摘要： The MEG experiment is to look for a lepton flavor violating μ + → e+γ decay with an unprecedented sensitivity, and we set an upper limit of the branching ratio for this decay, 5.7 × 10?13 at 90% C.L. in 2013 which is a twenty times more stringent limit than the previous experiment, MEGA. Since the sensitivity improvement was limited by the accidental background, we have considered the major detector upgrade. A proposal was submitted to PSI committee, and was approved in 2013, which aims at a sensitivity enhancement of one order of magnitude compared with the current MEG experiment. Here mainly two components of the MEG detector will be introduced, a γ-ray calorimeter with 900 L of liquid xenon (LXe), and a pixelated timing counter. The LXe detector will be improved by increasing the granularity at the incident face, by replacing the current PMTs with a larger number of smaller photosensors (MPPC) and optimizing the photosensor layout also on the lateral faces. A new highly segmented, fast timing counter array will replace the old system to allow improved timing resolution capabilities.
关键词： visible and IR photons (solid-state),HPG,Large detector systems for particle and astroparticle physics,Photon detectors for UV,CZT,Gamma detectors (scintillators,HgI etc),Timing detectors
更新于2025-09-23 15:23:52
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Development and evaluation of polycrystalline cadmium telluride dosimeters for accurate quality assurance in radiation therapy
摘要： For quality assurance in radiation therapy, several types of dosimeters are used such as ionization chambers, radiographic films, thermo-luminescent dosimeter (TLD), and semiconductor dosimeters. Among them, semiconductor dosimeters are particularly useful for in vivo dosimeters or high dose gradient area such as the penumbra region because they are more sensitive and smaller in size compared to typical dosimeters. In this study, we developed and evaluated Cadmium Telluride (CdTe) dosimeters, one of the most promising semiconductor dosimeters due to their high quantum efficiency and charge collection efficiency. Such CdTe dosimeters include single crystal form and polycrystalline form depending upon the fabrication process. Both types of CdTe dosimeters are commercially available, but only the polycrystalline form is suitable for radiation dosimeters, since it is less affected by volumetric effect and energy dependence. To develop and evaluate polycrystalline CdTe dosimeters, polycrystalline CdTe films were prepared by thermal evaporation. After that, CdTeO3 layer, thin oxide layer, was deposited on top of the CdTe film by RF sputtering to improve charge carrier transport properties and to reduce leakage current. Also, the CdTeO3 layer which acts as a passivation layer help the dosimeter to reduce their sensitivity changes with repeated use due to radiation damage. Finally, the top and bottom electrodes, In/Ti and Pt, were used to have Schottky contact. Subsequently, the electrical properties under high energy photon beams from linear accelerator (LINAC), such as response coincidence, dose linearity, dose rate dependence, reproducibility, and percentage depth dose, were measured to evaluate polycrystalline CdTe dosimeters. In addition, we compared the experimental data of the dosimeter fabricated in this study with those of the silicon diode dosimeter and Thimble ionization chamber which widely used in routine dosimetry system and dose measurements for radiation therapy.
关键词： X-ray detectors,Dosimetry concepts and apparatus,Solid state detectors,Materials for solid-state detectors
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC) - Shenzhen, China (2018.11.4-2018.11.7)] 2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC) - A 25kW SiC Universal Power Converter Building Block for G2V, V2G, and V2L Applications
摘要： This paper presents a universal power converter building block (PCBB) with isolation transformer which can perform various functionalities such as charging (G2V), vehicle to grid (V2G) regenerative capability, and vehicle to load (V2L) feature. This converter can output different types of voltage, such as AC or DC, high voltage or low voltage, single-phase or three-phase. With different combinations of modularized PCBB, various voltage and power rating can also be achieved. The control algorithms for each operation mode are explained, including G2V, V2G, and V2L. Simulation results are accompanied to validate its capability. To achieve high power density, SiC MOSFET power module with high frequency switching is adopted along with the isolation transformer of nanocrystalline core. Overall, this paper extends a promising circuit topology of multiple practical and essential features for vehicle electrification.
关键词： Vehicle to Grid (V2G),Dual Active Bridge,Vehicle to Load (V2L),Solid State Transformer,Bidirectional DC/DC,On-board Charger,Electric Vehicle
更新于2025-09-23 15:22:29
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A comparative study of Sr-doped LaMnO <sub/>3</sub> synthesised via solid-state reaction and sol–gel methods
摘要： This work deals with the synthesis of hole-doped La1-xSrxMnO3 (x = 0.25 and 0.33) perovskite via two different ways, namely a solid-state reaction method and a sol–gel process. Various properties of the samples have been investigated and compared by means of different techniques, namely X-ray diffraction (XRD), temperature-dependent resistivity measurements in the temperature range 25–300 K using a closed cycle refrigerator and vibrating sample magnetometry (VSM). All samples have orthorhombic crystal symmetry and an irregular variation in unit-cell volume with increase in Sr content. The average crystallite size was determined from the XRD data and found to lie in the range 19–22 nm. Metal–insulator transitions (MIT) were observed in all the samples via low-temperature electrical characterisations. The magnetic measurements confirm that the magnetisation does not saturate for the 25% Sr doped samples up to the available field of 10 kOe. The magnetic response also supports the interpretation of XRD and resistivity data. The obtained results are explained on the basis of double-exchange and super-exchange mechanisms.
关键词： CMR,manganites,metal to insulator transition (MIT),sol–gel method,Solid-state reaction
更新于2025-09-23 15:22:29
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Multi-band Polarimetry of the Lunar Surface. II. Grain Size Evolutionary Pathway
摘要： To understand grain size evolution on the lunar surface in detail, we analyze the distribution of the average grain size dá ? for the lunar near side obtained by Jeong et al. Furthermore, we analyze the polarimetric properties of the regolith simulants SiC and JSC-1A in a laboratory. We ?nd two characteristics of grain size evolution on the Moon. First, the lunar regolith has evolved on a speci?c evolutionary pathway in dá ? F– space. Here, Φ is de?ned as the ratio of the perpendicular (I^) and parallel (I?) components of the re?ectance. Second, we also ?nd that the evolutionary pathway depends on the FeO abundance and selenographic latitude of the surface. The dependence on the FeO content seems to result from the different resistance to comminution of regolith materials, and the dependence on the latitude seems to result from differences in the resurfacing environment. We present the probable causes of these characteristics of grain size evolution on the lunar surface.
关键词： Moon,techniques: polarimetric,methods: laboratory: solid state,methods: observational,polarization,planets and satellites: surfaces
更新于2025-09-23 15:22:29
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Enhancing Viologen's Electrochromism by Incorporating Thiophene: A Step Toward All‐Organic Flexible Device
摘要： An all-organic electrochromic device seems to be a possibility with ethyl viologen (EV) and poly-3-hexylthiophene (P3HT), both being organic materials, showing complementary electrochromic pair for color switching. The EV-P3HT layer, sandwiched between ITO-coated glass substrates shows switching between maroon and blue with an applied bias of 1.4 V. Mechanism of the color switching has been examined using UV-Vis and Raman spectroscopies. The fabricated device shows optical modulation of 80%, switching time of 1 s while maintaining cycle life for a period of more than 600 s. The paradigm reported here inches toward realizing a flexible all-organic electrochromic device.
关键词： solid state devices,P3HT,ethyl viologen,electrochromic
更新于2025-09-23 15:22:29
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Prediction of excitation wavelength of phosphors by using machine learning model
摘要： Luminescent materials are the integral part of green revolution helping us in saving the energy. Much effort been made to design and discover the novel phosphors for solid-state lighting. The current paper focuses on the development of machine learning (ML) model based on simple luminescent materials to predict the excitation to the closest possible accuracy using easily accessible key attributes using least absolute shrinkage and selection operator (LASSO) and artificial neural network (ANN) ML approach. These selected attributes expected to correlate with the excitation of material. The style for studying the material property has the potential to turn down the cost and time involved in an Edisonian approach to the lengthy lab experiment to identify excitation.
关键词： Solid-state lighting,Phosphor,Machine learning,Excitation wavelength,Luminescence
更新于2025-09-23 15:22:29
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Engineering of hollow AlAu2 nanoparticles on sapphire by solid state dewetting and oxidation of Al
摘要： The Al-Au binary diffusion couple is a classic example of the system exhibiting Kirkendall voiding during interdiffusion. We demonstrate that this effect, which is a major reason for failures of the wire bonds in microelectronics, can be utilized for producing hollow AlAu2 nanoparticles attached to sapphire substrate. To this end, we produced the core-shell Al-Au nanoparticles by performing a solid state dewetting treatment of Al thin film deposited on sapphire substrate, followed by the deposition of thin Au layer on the top of dewetted sample. Annealing of the core-shell nanoparticles in air resulted in outdiffusion of Al from the particles, formation of pores, and growth of the AlAu2 intermetallic phase in the particles. We demonstrated that the driving force for hollowing is the oxidation reaction of the Al atoms at the Au-sapphire interface, leading to the homoepitaxial growth of newly formed alumina at the interface. We developed a kinetic model of hollowing controlled by diffusion of oxygen through the Au thin film, and estimated the solubility of oxygen in solid Au. Our work demonstrates that the core-shell nanoparticles attached to the substrate can be hollowed by the Kirkendall effect in the thin film spatially separated from the particles.
关键词： Diffusion,Nanovoid,Solid state reaction,Kirkendall effect,Nanoparticles
更新于2025-09-23 15:22:29