- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Development of a sub-miniature gamma camera for multimodal imaging system
摘要： In the recent past, gamma-ray imaging detectors have achieved an intrinsic spatial resolution of less than 1 mm within a few centimeters of a useful field of view (UFOV). Unlike to conventional gamma cameras, which are large and heavy, the compact gamma-ray imaging detectors can improve the performances of the gamma cameras used in the various fields. In this study, we developed a sub-miniature gamma camera for a multimodal imaging system. The camera has a gamma-ray detector, miniature electronics modules, and a diverging hole collimator. The detector consisted of the sub-millimeter pixelated Ce:GAGG array and the silicon photomultiplier (SiPM) array module. We organized the miniature electronics modules according to the functions; an MPPC base board, analog signal processing board, integrated power supply board, and compact data acquisition (DAQ) base board. The diverging hole collimator widened an imaging area of the gamma camera from the UFOV of the detector. On the detector side, dimensions of each hole and septa were identical to the pixel and inter-pixel thickness of the reflector of scintillator array. For the intrinsic performance test, we acquired a flood map image of 729 (27 × 27) scintillator pixels, and the energy resolution was 18.9 % for an integrated energy histogram of 99mTc (140 keV). For the extrinsic performance test, we used the 57Co sheet source, and made a 99mTc line source using a capillary tube. The sources located at 10 cm apart from the collimator surface. The imaging area was three times wider than the UFOV of the detector. The system sensitivity was 19 CPM/μCi and the spatial resolution was 3.5 mm. The usability of the proposed gamma camera will not be confined to existing applications due to its compactness and novelty.
关键词： Sub-miniature gamma camera,Gamma camera performance evaluation,Front-end electronics,Multimodal imaging system,Diverging hole collimator
更新于2025-09-23 15:23:52
-
A New Hands-on Course in Characterization of Wide Bandgap Devices
摘要： As wide bandgap (WBG) devices and applications move from niche to mainstream, a new generation of engineers trained in this area is critical to continue the development of the field. This paper introduces a new hands-on course in characterization of WBG devices, which is an emerging and fundamental topic in WBG-based techniques. First, the lecture-simulation-experiment format based course structure and design considerations, such as safety, are presented. Then the necessary facilities to support this hands-on course are summarized, including classroom preparation, software tools, and laboratory equipment. Afterward, the detailed course implementation flow is presented to illustrate the approach of close interaction among lecture, simulation, and experiment to maximize students’ learning outcomes. Finally, grading for students and course evaluation by students are discussed with the findings and potential improvements highlighted. Detailed course materials are provided via potenntial.eecs.utk.edu/WBGLab for educational use.
关键词： electrical engineering education,power electronics,hands-on training,WBG devices
更新于2025-09-23 15:23:52
-
RF Characterization of NiO and TiO <sub/>2</sub> Based Metal-Insulator-Metal (MIM) Diodes on Flexible Substrates
摘要： This paper presents the fabrication and characterization of metal-insulator-metal (MIM) diodes on flexible substrates for RF and microwave circuit applications. Diodes using two types of insulators, titanium dioxide (TiO2) and nickel oxide (NiO), are investigated. These insulators are obtained using different oxidation techniques, i.e., in-situ oxidation for TiO2 and plasma oxidation for NiO. Asymmetric metal contacts (Ti-TiO2-Pd and Ni-NiO-Mo) are utilized to achieve nonlinear I–V characteristics. The fabricated diodes show strong non-linearity, high current densities, and low turn-ON voltage. The diodes show RF to dc rectification with near-ideal behavior and rectification sensitivity of 22 V/W (18 GHz) and 46 V/W (18 GHz) for TiO2 and NiO, respectively. NiO-based diodes barrier shows higher current density and higher cutoff frequency in comparison with TiO2 as expected diodes due to thinner oxide and lower dielectric constant. The diodes also work well as frequency doublers over a wide frequency range of 1–4 GHz for TiO2 and 2–10 GHz for NiO-based diodes. Good dc and RF performance of diodes indicate that good quality oxide can be achieved on plastic substrates and MIM devices can provide a perfect solution for RF and microwave circuits on a flexible substrate.
关键词： MIM diodes,rectification,Flexible electronics,harmonic generation,thin film devices,microwave circuits
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE XXVII International Scientific Conference Electronics (ET) - Sozopol, Bulgaria (2018.9.13-2018.9.15)] 2018 IEEE XXVII International Scientific Conference Electronics - ET - Performance of the Front-End Electronics of the PADME charged particle detector system
摘要： The PADME charged particle detector system should detect positrons and electrons with efficiency better than 99 % and time resolution below 1 ns. The system hosts about 200 readout electronics channels whose operation has to be verified and commissioned. A custom based test system allowing to perform qualitative check of the produced front-end electronics has been developed and was used to test a total of 256 channels. The obtained time resolution was found to be consistent with the requirements and better than 500 ps for all the channels.
关键词： scintillation detectors,front-end electronics,LED driver
更新于2025-09-23 15:23:52
-
Enhanced mobility in LaAlO3/SrTiO3 heterostructures with layer-modulated patterning
摘要： Overcoming the unintentional doping of defect-related carriers induced from low oxygen partial pressure is a major challenge to realize multifunctional oxide electronics. In this work, we demonstrate that the two-step deposition in conjunction with layer modulated patterning process can enhance several properties of LaAlO3/SrTiO3 (LAO/STO) heterostructures grown under a low oxygen partial pressure of 5 × 10?8 Torr. Specifically, our patterned samples exhibit extraordinary electronic properties including positive colossal magnetoresistance of ～3500% under 10 T, and enhanced carrier mobility ~5000 cm2/Vs at 2 K without using buffer layer or using additional elements. These unique phenomena are resulted from inhibition of the multiband conducting behaviour, which likely originates from oxygen vacancy related defects in the STO layers, through the two-step fabrication method. Consequently, by controlling defect behaviour through the two-step deposition jointly with modulated patterning process, several properties for oxide-based electronics can be induced in a single platform even under a low oxygen condition.
关键词： Oxide electronics,Heterostructures,Electronic properties
更新于2025-09-23 15:23:52
-
Experimental performance of a highly-innovative low-noise charge-sensitive preamplifier with integrated range-booster
摘要： Integrated charge-sensitive preamplifiers suffer from a reduced available dynamic range respect to discrete-type equivalents. This is due to the limits on maximum supply voltages that modern scaled technologies can tolerate. In this work we present a low-noise low-power integrated charge-sensitive preamplifier (CSP) for solid-state detectors. This device is equipped with an integrated range-booster that can enhance the spectroscopic range of the preamplifier by more than one order of magnitude, enabling high-resolution spectroscopy even if the preamplifier is in deep saturation condition. If the input signals from the detector are under the natural saturation threshold (40 MeV), the preamplifier works in an usual linear way, producing at the output the typical exponential signals. With proper filtering a resolution of approximately 1 keV is achievable. When a large signal from the detector saturates the preamplifier, a sensing circuit detects the saturation and switches the operation mode of the CSP to the “fast-reset mode”. In this mode a constant and controlled current generator discharges the input node of the preamplifier until the normal operating point is reached. Meanwhile an auxiliary circuit similar to a TAC (Time-to-Amplitude converter) retrieves the energy of the signal that caused saturation. Although the natural dynamic range of the CSP is 40 MeV, the fast-reset mode enables for high-resolution spectroscopy (under 0.2% FWHM) up to several hundreds of MeV (700 MeV typically). One issue in this kind of circuits is the dependence of the energy measured with the TAC circuit on the baseline value of the CSP before the “fast-reset event” [5]. As a solution to this problem we propose a correction algorithm implemented inside the TAC block in the form of an analog circuit. On a test-bench a series of large 3 pC charge signals is injected in the input node of the preamplifier through a test capacitor. Before these events, residual charges ranging from 0 to 0.56 pC produce non-zero baseline voltages at the output of the CSP. The TAC with correction not only retrieves correctly the energy of the main event, but also rejects the baseline voltages, leaving the energy measurement unaffected. The fluctuations of the flat-top voltage in the signals produced by the auxiliary TAC circuit due to the different baseline voltages are under the 0.6% of the total signal amplitude.
关键词： Front-end electronics for detector readout,VLSI circuits,Analogue electronic circuits,Electronic detector readout concepts (solid-state)
更新于2025-09-23 15:23:52
-
Addressing of imperfection of a hybrid pixel sensor for X-ray detection with a circuit for charge sharing cancellation implemented
摘要： A developing trend in the design of event-driven sensors for X-ray detection are hybrid pixel detectors working in the single photon counting mode. The factors limiting detector performance, especially for small pixel sizes, include among others, mismatch of circuit components due to process variations, electronic noise and charge sharing. Charge sharing in a hybrid pixel detector occurs when the charge generated in X-ray photon interaction with a sensor is collected by more than one pixel. Charge sharing effect may significantly impair the detector energy resolution and result in counting extra events or missing some of the events. The impact of the charge sharing increases with a decrease of the pixel sizes. The small pixel size is a desired feature of a novel hybrid X-ray detector, as it allows better spatial resolution and helps to overcome the high count rate limits by accepting more photons per unit area. Therefore, the charge sharing effect must be dealt with by a dedicated readout IC or processed off-chip. Minimization of the analog parameters dispersion in the pixel matrix is crucial for the circuits designed for charge sharing cancellation. The chip’s sensitivity to the analog parameters spread and mitigation of the performance achieved with the digital correction blocks are studied. The DC offsets and gains spread can be optimized using correction circuits and dedicated trimming algorithms. Detection efficiency in case of charge sharing for the corrected and uncorrected pixel matrix is addressed. The simulation results as well as pencil beam measurements using synchrotron radiation are presented.
关键词： Front-end electronics for detector readout,Analogue electronic circuits,Digital electronic circuits
更新于2025-09-23 15:23:52
-
Evaluation of the optical cross talk level in the SiPMs adopted in ASTRI SST-2M Cherenkov Camera using EASIROC front-end electronics
摘要： ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), is a flagship project of the Italian Ministry of Education, University and Research whose main goal is the design and construction of an end-to-end prototype of the Small Size of Telescopes of the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, will adopt a wide field dual mirror optical system in a Schwarzschild-Couder configuration to explore the VHE range of the electromagnetic spectrum. The camera at the focal plane is based on Silicon Photo-Multipliers detectors which is an innovative solution for the detection astronomical Cherenkov light. This contribution reports some preliminary results on the evaluation of the optical cross talk level among the SiPM pixels foreseen for the ASTRI SST-2M camera.
关键词： Front-end electronics for detector readout,Gamma detectors,Cherenkov detectors,Gamma telescopes
更新于2025-09-23 15:23:52
-
Carbon Nanotube Thin Films for High-Performance Flexible Electronics Applications
摘要： Carbon nanotube thin films have attracted considerable attention because of their potential use in flexible/stretchable electronics applications, such as flexible displays and wearable health monitoring devices. Due to recent progress in the post-purification processes of carbon nanotubes, high-purity semiconducting carbon nanotubes can be obtained for thin-film transistor applications. One of the key challenges for the practical use of carbon nanotube thin-film transistors is the thin-film formation technology, which is required for achieving not only high performance but also uniform device characteristics. In this paper, after describing the fundamental thin-film formation techniques, we review the recent progress of thin-film formation technologies for carbon nanotube-based flexible electronics.
关键词： Flexible electronics,Carbon nanotube,Thin film
更新于2025-09-23 15:23:52
-
Nano-rheology printing of sub-0.2 <i>μ</i> m channel length oxide thin-film transistors
摘要： Down-scaling of the channel length of a fully solution-processed oxide thin-film transistor (TFT) to the nanometer-scale is the key to accessing next-generation devices for Internet-of-Things technology. In this work, we report on the fabrication of an oxide TFT with a channel length of 160 nm, which is far less than those obtained by the current direct-printing techniques, by a newly developed nano-rheology printing (nRP) method. The device had an on/off current ratio, subthreshold voltage, hysteresis, and field-effect mobility of approximately 107, 1.7 V, 0 V, and 0.16 cm2 V s-1, respectively. The key to achieving the sub-micron channel printed TFT is the introduction of a new amorphous La–Ru–O material, which exhibits relatively good conductivity and excellent nRP properties at the nanoscale, for source/drain electrode patterns. Such a short-channel TFT would never be achieved with conventional printing methods, and hence, this approach is highly important for accessing next-generation low-cost, large-area and environmentally friendly printed electronics.
关键词： nano-rheology printing,thermal-imprinting,printed electronics,solution process,oxide thin-film transistor
更新于2025-09-23 15:23:52