- 标题
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- 实验方案
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - The failure analysis of LED sulfur corrosion
摘要： As a common problem of LED failure, the sulfur corrosion that can cause the LED luminous flux reduced, LED color temperature drifted, in the most severe cases, LED damaged. The sulfur corrosion of LED which affected the reliability of LED was always the focus of research. In this paper, the general analysis methods about the LED sulfur corrosion were clearly elaborated. The SEM&EDS, TOF-SIMS and AES were applied, which provided new methods to analysis the sulfur corrosion. Meanwhile, the corrosion path was discussed. Then, how to avoiding the sulfur corrosion of LED was also suggested.
关键词： TOF-SIMS,corrosion path,AES,sulfur corrosion
更新于2025-09-09 09:28:46
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A compact Time-Of-Flight detector for radiation measurements in a space habitat: LIDAL–ALTEA
摘要： LIDAL–ALTEA is a detector designed to study the radiation flux and energy spectra in the International Space Station (ISS). Its mission is manifested by NASA in 2019. The ALTEA subsystem, which took data on the ISS in the past Zaconte et al. (2010), is based on Silicon Strip detectors and will measure the released energy of the traversing particles, while the LIDAL subdetector is based on fast plastic scintillators, read by PMTs, will measure the particle Time Of Flight. A custom Front End electronics has been designed to reach a time resolution better than 120 ps. LIDAL is under construction while a prototype has been already tested with a proton beam. The measured time resolution fulfills the design expectation and is compatible with FLUKA simulations. The Monte Carlo results have also been validated by the comparison with a test measure where the ALTEA detector was exposed to proton beams.
关键词： Space,TOF detectors,Silicon detectors,FLUKA
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Pico-TDC: a novel FPGA-based TDC with 2.2ps RMS timing resolution
摘要： The purpose of this work is to develop low-cost high-performance TDCs to meet the requirement from the next generation sub-10ps TOF-PET camera. A TOF-PET system may need hundreds of high resolution TDCs to read timing from many detectors. FPGA-based TDC designs, such as conventional delay-line (DL) TDCs and Wave-Unions (WU) TDCs, are a more viable solutions compared with expensive ASIC-based TDCs. However, the performances of those FPGA-based TDCs are more or less depended on the specific structures and performances of the delay lines, which are usually the carry chains in the adders of a FPGA. In this paper, we present a new method called Pico-TDC method to construct the TDCs in FPGA. The uniqueness of the Pico-TDC method is to use single registers in the FPGA as low-precision TDCs, and to combine many of those low-precision TDCs to construct a high-precision TDC. The advantages of Pico-TDC method are: (1) the timing performance of a Pico-TDC is not limited by the performance of delay lines in the FPGA. As a result, it is possible to achieve unprecedented resolution with a low-cost FPGA. (2) Hundreds of high-performance Pico-TDCs can be constructed in a low-cost FPGA which normally has millions of registers. (3) Theoretically, the Pico-TDCs can be conveniently migrated from one FPGA to another, regardless of the differences in the internal structures of the FPGAs. We have successfully constructed four channels of Pico-TDCs in a low-cost FPGA (Altera Cyclone V 5CEBA4F23C7N, price: $66.63). Each TDC uses 640 registers (low-precision TDCs). The four Pico-TDCs were tested with both the internal and the external pulses. The RMS of the timing measurements is 2.2 ps. The temperature stability is excellent. We conclude that Pico-TDCs have excellent timing performance which meets the requirement of the next generation sub-10ps TOF-PET.
关键词： TDC,TOF-PET,timing resolution,FPGA,Pico-TDC
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN) - Nantes (2018.9.24-2018.9.27)] 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN) - An Analytical Study of Time of Flight Error Estimation in Two-Way Ranging Methods
摘要： In absence of clock synchronization, Two-Way Ranging (TWR) is the most commonly used technique for measuring the distance between two wireless transceivers. The existing time-of-flight (TOF) error estimation model, the IEEE 802.15.4-2011 standard, is specifically based on clock drift error. However, it is insufficient when an in-depth comparative analysis of different TWR methods is required. In this paper, we propose an extended TOF error estimation model for TWR methods, based on the IEEE 802.15.4 standard. Using the proposed model, we perform an analytical study of TOF error estimation among different TWR methods. The model is validated with numerical simulation results. Moreover, we demonstrate the pitfalls of the symmetric double-sided TWR (SDS-TWR) method, which is commonly used to reduce the TOF error due to clock drifts.
关键词： two way ranging (TWR),time of flight (TOF),time of arrival (TOA),TOF error model,analytical model,indoor positioning,time based ranging techniques
更新于2025-09-04 15:30:14
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Internal Energy Distribution of Secondary Ions Under Argon and Bismuth Cluster Bombardments: “Soft” Versus “Hard” Desorption–Ionization Process
摘要： The emission/ionization process under massive argon cluster bombardment was investigated by measuring the internal energy distributions of a series of benzylpyridinium ions. Argon clusters with kinetic energies between 10 and 20 keV and cluster sizes ranging from 500 to 10,000 were used to establish the influence of their size, energy, and velocity on the internal energy distribution of the secondary ions. It is shown that the internal energy distribution of secondary ions principally depends on the energy per atom or the velocity of the cluster ion beam (E/n ∝ v2). Under low energy per atom (E/n ? 10 eV), the mean internal energy and fragmentation yield increase rapidly with the incident energy of individual constituents. Beyond 10 eV/atom impact (up to 40 eV/atom), the internal energy reaches a plateau and remains constant. Results were compared with those generated from bismuth cluster impacts for which the mean internal energies correspond well to the plateau values for argon clusters. However, a significant difference was found between argon and bismuth clusters concerning the damage or disappearance + impact cross section. A 20 times smaller disappearance cross section was measured under 20 keV Ar2000 + bombardment, thus quantitatively showing the low damage effect of large argon clusters compared to 25 keV Bi5 for almost the same molecular ion yield.
关键词： Bismuth cluster,Argon cluster,Internal energy,TOF-SIMS,Benzylpyridinium ion
更新于2025-09-04 15:30:14
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SENSING IMMOBILIZED MOLECULES OF STREPTAVIDIN ON A SILICON SURFACE BY MALDI-TOF MASS SPECTROMETRY AND FLUORESCENCE MICROSCOPY
摘要： A hydrogen-terminated Si (111) surface was modified to form an aminoterminated monolayer for immobilization of streptavidin. Cleavage of an N-(ω-undecylenyl)-phthalimide covered surface using hidrazine yields an amino group-modified surface, which serves as a substrate for the attachment of biotin and subsequently streptavidin. We used surface analytical techniques to characterize the surface and to control the course of functionalization before the immobilization of streptavidin. To confirm the presence of the streptavidin Texas red on the surface two powerful techniques available in a standard biochemical laboratory are used, Fluorescence Microscopy and MALDI-TOF that allow us to detect and determine the immobilized streptavidin. This work provides an avenue for the development of devices in which the exquisite binding specificity of biomolecular recognition is directly coupled to a biosensor. In addition, we have demonstrated that MALDI-TOF and fluorescence microscopy are useful techniques for the characterization of silicon functionalized surfaces.
关键词： streptavidin,fluorescence microscopy,MALDI-TOF,biosensor,silicon surface
更新于2025-09-04 15:30:14
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SPAD-Based LiDAR Sensor in 0.35 μm Automotive CMOS with Variable Background Light Rejection
摘要： We present a SPAD-based LiDAR sensor fabricated in an automotive certified 0.35 μm CMOS process. Since reliable sensor operation in high ambient light environment is a crucial factor in automotive applications, four SPADs are implemented in each pixel to suppress ambient light by the detection of photon coincidences. By pixel individual adjustment of the coincidence parameters to the present ambient light condition, an almost constant measurement performance is achieved for a wide range of different target reflectance and ambient illumination levels. This technique allows the acquisition of high dynamic range scenes in a single laser shot. For measurement and demonstration purpose a LiDAR camera with the developed sensor has been built.
关键词： time-of-flight (TOF),background rejection,single-photon avalanche diode (SPAD),range imaging,light detection and ranging (LiDAR),photon coincidence
更新于2025-09-04 15:30:14
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[IEEE 2018 - 3DTV-Conference: The True Vision - Capture, Transmission and Display of 3D Video (3DTV-CON) - Helsinki (2018.6.3-2018.6.5)] 2018 - 3DTV-Conference: The True Vision - Capture, Transmission and Display of 3D Video (3DTV-CON) - ICP WITH DEPTH COMPENSATION FOR CALIBRATION OF MULTIPLE TOF SENSORS
摘要： We propose an iterative closest point (ICP) based calibration for time of flight (ToF) multiple depth sensors. For the multiple sensor calibrations, we usually use 2D patterns calibration with IR images. The depth sensor output depends on calibration parameters at a factory; thus, the re-calibration must include gaps from the calibration in the factory. Therefore, we use direct correspondences among depth values, and the calibrating extrinsic parameters by using ICP. Usually, simultaneous localization and mapping (SLAM) uses ICP, such as KinectFusion. The case of multiple sensor calibrations, however, is harder than the SLAM case. In this case, the distance between cameras is too far to apply ICP. Therefore, we modify the ICP based calibration for multiple sensors. The proposed method uses specific calibration objects to enforce the matching ability among sensors. Also, we proposed a compensation method for ToF depth map distortions.
关键词： Calibration,Multiple RGB-D camera,ToF,ICP,Multiple Kinect
更新于2025-09-04 15:30:14
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA, USA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Design of a Photoneutron Convertor for Energy Selective Neutron Imaging
摘要： Neutron imaging plays an essential role in the industrial applications, such as turbine blade manufacturing, fuel cell research, and nuclear fuel quality inspection. As isotopic neutron sources and neutron generators cannot provide high-intensity neutron beams, and neutron beam lines of research reactors or spallation neutron sources are very scarce, a cost-effective neutron source with high neutron yield and long life-span should be researched. The e-LINAC driven photoneutron source, which converts X-rays to photoneutrons, has been proved to be a robust neutron source that can realize neutron yield ranging from 1010 to 1015n/s. Hence it is a promising neutron source to provide neutron beams used for the neutron imaging. Because the e-LINAC works at a pulsed mode and the photoneutrons have a continuous energy spectrum, energy selective neutron imaging can thus be realized with the e-LINAC driven photoneutron source, with the aid of time of flight (TOF) technique. In this research, an e-LINAC driven photoneutron source is researched to strike the compromise between the neutron flux and the energy resolution. With a well-designed heavy water photon-to-neutron convertor, a 10 MeV/ 20 kW e-LINAC can provide a thermal neutron flux of 7.28×104n/cm2/s at 10 meters away from the electron target, with an energy resolution less than 20%. By using a low temperature (10K) moderator, the cold neutron flux at the same position can be 2.13×104n/cm2, and the energy resolution is less than 2%. This study may help realize the energy selective neutron imaging with an e-LINAC driven photoneutron source.
关键词： Neutron imaging,e-LINAC,energy selective neutron imaging,photoneutron source,time of flight (TOF)
更新于2025-09-04 15:30:14