Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-05-06
Abstract: In this work, a design of transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA with the tip-sample component in CryoSTM is called as CryoSTM-TIA. With transimpedance gain of 1 Gohm, the bandwidth of the CryoSTM-TIA is larger than 200 kHz. The distinctive feature of the proposed CryoSTM-TIA is that its pre-amplifier is made of a single cryogenic high electron mobility transistor (HEMT), so the apparatus equivalent input noise current power spectral density at 100 kHz is lower than 6 (fA)2/Hz. In addition, bias-cooling method can be used to in-situ control the density of the frozen DX- centers in the HEMT doping area, changing its structure to reduce the device noises. With this apparatus, fast scanning tunneling spectra measurements with high-energy-resolution are capable to be performed. And, it is capable to measure scanning tunneling shot noise spectra (STSNS) at the atomic scale for various quantum systems, even if the shot noise is very low. It provides a powerful tool to investigate novel quantum states by measuring STSNS, such as detecting the existence of Majorana bound states in the topological quantum systems.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2024-05-06
Abstract: In this work, we design and fabricate the transimpedance Amplifier (TIA) following the design mentioned in Ref. 1 . In the TIA, the preamplifier (Pre-Amp) is made of a junction field effect transistor (JFET) that can work at 77 K. The post-amplifier (Post-Amp) is made of an operational amplifier. Cascade Pre-Amp and Post-Amp to form the inverting-amplifier. With a 1.13 Gohm feedback network, the gain of TIA is 1.13 Gohm and its bandwidth is about 97 kHz. The equivalent input noise voltage power spectral density of TIA is not more than 9 (nV)2/Hz at 10 kHz and 4 (nV)2/Hz at 50kHz, and its equivalent input noise current power spectral density is about 26 (fA)2/Hz at 10 kHz and 240 (fA)2/Hz at 50 kHz. The measured transport performances and noise performances of TIA are consistent with the simulations and calculations. As an example, the realization of TIA in this work verifies the design method and analytical calculations for the low-noise large-bandwidth high-gain TIA proposed in Ref. 1,2 . And, the TIA in this work is perfect for the cryogenic STM working at liquid nitrogen temperature.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2024-01-30
Abstract: In the scope of our investigation, we have solved the stability problem of the boost converter. Ouyang Changlian's doctoral dissertation made me realize the importance of duty cycle in control system.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Particle Accelerator Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-11-29
Abstract: In light of the current international energy scarcity, nuclear power has emerged as a crucial source of clean energy. Proton accelerators have therefore become a pivotal technology in nuclear waste management. During beamline orbit correction processes, precise calculations of beamline orbit parameters are required. Given the demonstrated effectiveness of neural networks in a wide variety of industry domains, they offer promising potential for high-accuracy data fitting and prediction. Hence, this study proposes a novel direct linear accelerator beamline orbit parameter prediction technique based on edge intelligence computing nodes. This technique leverages BPNN to learn from historical data and generate a powerful model that can be seamlessly deployed to edge computing nodes, thereby accelerating the prediction of BPM location parameters. Furthermore, the proposed approach may be complemented by an adaptive compensation system in the future, which, in combination with edge computing nodes, could enable automatic beamline position correction, thereby achieving beamline orbit correction. Our experimental results demonstrate that FPGA, as an edge acceleration node, can achieve an inference speed of 2.5us, which represents a remarkable performance enhancement of approximately 165.6 times compared to CPU and approximately 7.9 times compared to GPU. The predicted results exhibit an average error of only 0.5%, and they exhibit the desired latency and accuracy characteristics.
Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-06-15
Abstract: Analog IC design faces a series of challenges. Druing design phase, the number of performance indicators that need to be met increases rapidly, along with more non-ideal factors that need to be balanced. It is difficult to effectively meet the needs of design exploration and simulation scheduling by using simulation-oriented models alone. System-level modeling is required to comprehensively address performance metrics and design constraints, and to adopt agile design methodologies to improve the efficiency of analog IC design efforts. Based on the framework of decoupling and separating circuit model and performance index calculation, this paper proposes a system-level modeling method for analog circuits that can handle complex constraints. This method gives a domain-specific language suitable for analog integrated circuit system-level modeling. The language contains the syntax elements and syntax protocols required for system-level modeling. According to the characteristics of analog integrated circuits, this method gives the semantic correspondence between the semantics of the modeling language elements and the circuit characteristics, and gives a modeling method that treats analog circuit components, topology and design constraints as components in the system to achieve decoupling. The model obtained by the above method uses graph as the basic data structure and supports graph calculation. this paper also presents system-level modeling tools including domain-specific language compilation, model storage, graph computing and other functions. Modeling cases are given to show the usability and applicability of the modeling method. This work shows that system-level modeling provides a feasible solution for solving the decoupling of complex constraints in analog integrated circuit design.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter submitted time 2023-05-01
Abstract: In this work, a design of large-bandwidth high-gain low-noise transimpedance amplifier (TIA) for scanning tunneling microscope (STM) is proposed. The simulations show that the proposed TIA has the bandwidth higher than 200 kHz, two orders of magnitude higher than those of conventional commercial TIAs for STM. At low frequencies, the noises of the proposed TIA are almost the same as the conventional commercial ones with the same transimpedance gain. At high frequencies, its calculated input equivalent noise voltage power spectral density (PSD) is 40 (nV)2/Hz and its input equivalent noise current PSD is 3.2 (fA)2/Hz at 10 kHz. The corresponding values are 23 (nV)2/Hz and 88 (fA)2/Hz at 100 kHz. The STM with the proposed TIA can meet the needs of fast high-quality STM imaging measurements and fast high-energy-resolution scanning tunneling spectra measurements for the low-conducting materials, such as complex organic systems and wide bandgap semiconductors.
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-05-01
Abstract: An ultra-low-noise large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. Its transimpedance gain is as high as 1 GΩ, and its bandwidth is over 300 kHz, but its equivalent input noise current power spectral density is less than 4 (fA)2/Hz at 100 kHz. The low inherent noise for the CryoSTM-TIA is due to its special design: (1) its pre-amplifier is made of a pair of low-noise cryogenic high electron mobility transistors (HEMTs); (2) the noise generated by one HEMT is eliminated by a large capacitor; (3) the capacitance of the cable connected the gate of the other HEMT to the tip is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. The dc output voltage drift of the CryoSTM-TIA is very low, as 5 μV/°C. The apparatus can be used for measuring the scanning tunneling differential conductance spectra, especially the scanning tunneling shot noise spectra (STSNS) of quantum systems, even if the shot noise is very low. It provides a universal tool to study various novel quantum states by measuring STSNS, such as detecting the Majorana bound states.
Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-02-24
Abstract: Thyristor, RC damping circuit and valve arrester are the main part of primary loop of UHVDC valve, determining the cooperation the parameters of the three types of devices is the chief work in the electrical design of UHVDC valve, in this paper, the mechanism of the commutation overshoot was revealed, the interaction effect of the three types of devices was also confirmed, then the circuit differential equation was established , and the equation was solved by Piecewise fitting the reverse recovery current of thyritor, the precision of the calculation method that was put forward in the paper was proved by comparing the calculation results with the test results
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2022-12-29
Abstract:
A low-noise high-gain large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. The CryoSTM-TIA has a transimpedance gain of 10 Gohm, a bandwidth of over 100 kHz, and an equivalent input noise current power spectral density less than 4 (fA)2/Hz at 100 kHz. The low inherent noise of the CryoSTM-TIA is due to its special design: (1) its pre-amplifier (Pre-Amp) is made of the low-noise cryogenic high electron mobility transistors; (2) the cascode-type configuration for the Pre-Amp is used to avoid Miller effect to reduce its input capacitance CA; (3) the capacitance of the cable connected the Pre-Amp input to the tip, i.e. CI, is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. Its high gain and large-bandwidth are realized together, due to the application of the frequency compensation in the feedback loop, the reduced CA, and the minimized CI. This apparatus can be used for fast high-energy-resolution measurements of scanning tunneling spectra for low conductivity materials, especially for measuring their scanning tunneling shot noise spectra.
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2022-12-29
Abstract: Shot noise is a powerful tool to study quantum systems. In this work, a design of transimpedance amplifier (TIA) for a cryogenic scanning tunneling microscope (CryoSTM) is proposed to meet the requirements of the shot noise measurements for quantum systems. In the TIA, the preamplfier is made of the low-noise low-power cryogenic high electron mobility transistors. With the high transimpedance gain of 1 Gohm, the bandwidth of the proposed TIA is larger than 300 kHz. In the CryoSTM, the TIA with the tip-sample component is called as CryoSTM-TIA. The bandwidth of the proposed CryoSTM-TIA is still larger than 300 kHz. Its equivalent input noise current power spectral density is less than 30 (fA)2/Hz at 100 kHz. It is detailed, for quantum systems, by using the CryoSTM-TIA, how to measure scanning tunneling current spectra, scanning tunneling differential conductance spectra, and scanning tunneling noise current power spectra, in atomic scale, and then extract their scanning tunneling shot noise spectra. Thus, it is possible to study novel quantum phenomena in various quantum systems by measuring shot noise with the CryoSTM-TIA, such as the Andreev reflection in atomic scale, the Kondo effect in a single molecular magnet, and the existence of Majorana bound states, etc.
Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2018-06-25
Abstract: "
Peer Review Status:Awaiting Review