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Sample records for cmos current sources

  1. A tunable CMOS constant current source

    NASA Technical Reports Server (NTRS)

    Thelen, D.

    1991-01-01

    A constant current source has been designed which makes use of on chip electrically erasable memory to adjust the magnitude and temperature coefficient of the output current. The current source includes a voltage reference based on the difference between enhancement and depletion transistor threshold voltages. Accuracy is +/- 3% over the full range of power supply, process variations, and temperature using eight bits for tuning.

  2. CMOS current controlled fully balanced current conveyor

    NASA Astrophysics Data System (ADS)

    Chunhua, Wang; Qiujing, Zhang; Haiguang, Liu

    2009-07-01

    This paper presents a current controlled fully balanced second-generation current conveyor circuit (CF-BCCII). The proposed circuit has the traits of fully balanced architecture, and its X-Y terminals are current controllable. Based on the CFBCCII, two biquadratic universal filters are also proposed as its applications. The CFBCCII circuits and the two filters were fabricated with chartered 0.35-μm CMOS technology; with ±1.65 V power supply voltage, the total power consumption of the CFBCCII circuit is 3.6 mW. Comparisons between measured and HSpice simulation results are also given.

  3. Current-mode CMOS hybrid image sensor

    NASA Astrophysics Data System (ADS)

    Benyhesan, Mohammad Kassim

    Digital imaging is growing rapidly making Complimentary Metal-Oxide-Semi conductor (CMOS) image sensor-based cameras indispensable in many modern life devices like cell phones, surveillance devices, personal computers, and tablets. For various purposes wireless portable image systems are widely deployed in many indoor and outdoor places such as hospitals, urban areas, streets, highways, forests, mountains, and towers. However, the increased demand on high-resolution image sensors and improved processing features is expected to increase the power consumption of the CMOS sensor-based camera systems. Increased power consumption translates into a reduced battery life-time. The increased power consumption might not be a problem if there is access to a nearby charging station. On the other hand, the problem arises if the image sensor is located in widely spread areas, unfavorable to human intervention, and difficult to reach. Given the limitation of energy sources available for wireless CMOS image sensor, an energy harvesting technique presents a viable solution to extend the sensor life-time. Energy can be harvested from the sun light or the artificial light surrounding the sensor itself. In this thesis, we propose a current-mode CMOS hybrid image sensor capable of energy harvesting and image capture. The proposed sensor is based on a hybrid pixel that can be programmed to perform the task of an image sensor and the task of a solar cell to harvest energy. The basic idea is to design a pixel that can be configured to exploit its internal photodiode to perform two functions: image sensing and energy harvesting. As a proof of concept a 40 x 40 array of hybrid pixels has been designed and fabricated in a standard 0.5 microm CMOS process. Measurement results show that up to 39 microW of power can be harvested from the array under 130 Klux condition with an energy efficiency of 220 nJ /pixel /frame. The proposed image sensor is a current-mode image sensor which has several

  4. Lower-Dark-Current, Higher-Blue-Response CMOS Imagers

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Cunningham, Thomas; Hancock, Bruce

    2008-01-01

    Several improved designs for complementary metal oxide/semiconductor (CMOS) integrated-circuit image detectors have been developed, primarily to reduce dark currents (leakage currents) and secondarily to increase responses to blue light and increase signal-handling capacities, relative to those of prior CMOS imagers. The main conclusion that can be drawn from a study of the causes of dark currents in prior CMOS imagers is that dark currents could be reduced by relocating p/n junctions away from Si/SiO2 interfaces. In addition to reflecting this conclusion, the improved designs include several other features to counteract dark-current mechanisms and enhance performance.

  5. Design, experimental verification, and analysis of a 1.8-V-input-range voltage-to-current converter using source degeneration for low-noise multimodal CMOS biosensor array

    NASA Astrophysics Data System (ADS)

    Niitsu, Kiichi; Ikeda, Kei; Muto, Keita; Nakazato, Kazuo

    2017-01-01

    A multimodal complementary metal-oxide semiconductor (CMOS) biosensor array manufactured using measurement methods such as potentiometry, amperometry, and impedimetry improves its cost competitiveness and measurement accuracy. In addition, it provides a wider range of application because it can obtain signals from multiple aspects. To develop high-signal-to-noise ratio (SNR) multimodal biosensor arrays, time-domain current integration was proposed in the literature and found to be effective. In addition to amperometry and impedimetry, it is possible to perform current integration using the potentiometry output by employing a voltage-to-current converter (VCC). However, a conventional VCC with a fixed transconductance mode does not provide a sufficient input range (<0.6 V) and its noise property has not been investigated. In this work, we investigate the design and noise property of a newly proposed VCC with source degeneration that enhances the input range. For evaluating the proposed method, a test chip was fabricated in a 0.6 µm CMOS. The measured results successfully demonstrate that the input range was enhanced from 0.6 to 1.8 V. Autonomous current limitation was also confirmed. The measured total input-referred noise was 0.445 mV (from 10 Hz to 10 kHz, assuming current integration at every 1 ms).

  6. Dark current study for CMOS fully integrated-PIN-photodiodes

    NASA Astrophysics Data System (ADS)

    Teva, Jordi; Jessenig, Stefan; Jonak-Auer, Ingrid; Schrank, Franz; Wachmann, Ewald

    2011-05-01

    PIN photodiodes are semiconductor devices widely used in a huge range of applications, such as photoconductors, charge-coupled devices and pulse oximeters for medical applications. The possibility to combine and to integrate the fabrication of the sensor with its signal conditioning circuitry in a CMOS process allows device miniaturization in addition to enhance its properties lowering the production and assembly costs. This paper presents the design and characterization of silicon based PIN photodiodes integrated in a CMOS commercial process. A high-resistivity, low impurity substrate is chosen as the start material for the PIN photodiode array fabrication in order to fabricate devices with a minimum dark current. The dark current is studied, analyzed and measured for two different starting materials and for different geometries. A model previously proposed is reviewed and compared with experimental data.

  7. Noise optimization of the source follower of a CMOS pixel using BSIM3 noise model

    NASA Astrophysics Data System (ADS)

    Mahato, Swaraj; Meynants, Guy; Raskin, Gert; De Ridder, J.; Van Winckel, H.

    2016-07-01

    CMOS imagers are becoming increasingly popular in astronomy. A very low noise level is required to observe extremely faint targets and to get high-precision flux measurements. Although CMOS technology offers many advantages over CCDs, a major bottleneck is still the read noise. To move from an industrial CMOS sensor to one suitable for scientific applications, an improved design that optimizes the noise level is essential. Here, we study the 1/f and thermal noise performance of the source follower (SF) of a CMOS pixel in detail. We identify the relevant design parameters, and analytically study their impact on the noise level using the BSIM3v3 noise model with an enhanced model of gate capacitance. Our detailed analysis shows that the dependence of the 1/f noise on the geometrical size of the source follower is not limited to minimum channel length, compared to the classical approach to achieve the minimum 1/f noise. We derive the optimal gate dimensions (the width and the length) of the source follower that minimize the 1/f noise, and validate our results using numerical simulations. By considering the thermal noise or white noise along with 1/f noise, the total input noise of the source follower depends on the capacitor ratio CG/CFD and the drain current (Id). Here, CG is the total gate capacitance of the source follower and CFD is the total floating diffusion capacitor at the input of the source follower. We demonstrate that the optimum gate capacitance (CG) depends on the chosen bias current but ranges from CFD/3 to CFD to achieve the minimum total noise of the source follower. Numerical calculation and circuit simulation with 180nm CMOS technology are performed to validate our results.

  8. A new circuit technique for reduced leakage current in Deep Submicron CMOS technologies

    NASA Astrophysics Data System (ADS)

    Schmitz, A.; Tielert, R.

    2005-05-01

    Modern CMOS processes in the Deep Submicron regime are restricted to supply voltages below 2 volts and further to account for the transistors' field strength limitations and to reduce the power per logic gate. To maintain the high switching performance, the threshold voltage must be scaled according with the supply voltage. However, this leads to an increased subthreshold current of the transistors in standby mode (VGS=0). Another source of leakage is gate current, which becomes significant for gate oxides of 3nm and below. We propose a Self-Biasing Virtual Rails (SBVR) - CMOS technique which acts like an adaptive local supply voltage in case of standby mode. Most important sources of leakage currents are reduced by this technique. Moreover, SBVR-CMOS is capable of conserving stored information in sleep mode, which is vital for memory circuits. Memories are exposed to radiation causing soft errors. This well-known problem becomes even worse in standby mode of typical SRAMs, that have low driving performance to withstand alpha particle hits. In this paper, a 16-transistor SRAM cell is proposed, which combines the advantage of extremely low leakage currents with a very high soft error stability.

  9. A compact picosecond pulsed laser source using a fully integrated CMOS driver circuit

    NASA Astrophysics Data System (ADS)

    He, Yuting; Li, Yuhua; Yadid-Pecht, Orly

    2016-03-01

    Picosecond pulsed laser source have applications in areas such as optical communications, biomedical imaging and supercontinuum generation. Direct modulation of a laser diode with ultrashort current pulses offers a compact and efficient approach to generate picosecond laser pulses. A fully integrated complementary metaloxide- semiconductor (CMOS) driver circuit is designed and applied to operate a 4 GHz distributed feedback laser (DFB). The CMOS driver circuit combines sub-circuits including a voltage-controlled ring oscillator, a voltagecontrolled delay line, an exclusive-or (XOR) circuit and a current source circuit. Ultrashort current pulses are generated by the XOR circuit when the delayed square wave is XOR'ed with the original square wave from the on-chip oscillator. Circuit post-layout simulation shows that output current pulses injected into an equivalent circuit load of the laser have a pulse full width at half maximum (FWHM) of 200 ps, a peak current of 80 mA and a repetition rate of 5.8 MHz. This driver circuit is designed in a 0.13 μm CMOS process and taped out on a 0.3 mm2 chip area. This CMOS chip is packaged and interconnected with the laser diode on a printed circuit board (PCB). The optical output waveform from the laser source is captured by a 5 GHz bandwidth photodiode and an 8 GHz bandwidth oscilloscope. Measured results show that the proposed laser source can output light pulses with a pulse FWHM of 151 ps, a peak power of 6.4 mW (55 mA laser peak forward current) and a repetition rate of 5.3 MHz.

  10. Design automation techniques for high-resolution current folding and interpolating CMOS A/D converters

    NASA Astrophysics Data System (ADS)

    Gevaert, D.

    2007-05-01

    The design and testing of a 12-bit Analog-to-Digital (A/D) converter, in current mode, arranged in an 8-bit LSB and a 4- bit MSB architecture together with the integration of specialized test building blocks on chip allows the set up of a design automation technique for current folding and interpolation CMOS A/D converter architectures. The presented design methodology focuses on the automation for CMOS A/D building blocks in a flexible target current folding and interpolating architecture for a downscaling technology and for different quality specifications. The comprehensive understanding of all sources of mismatching in the crucial building blocks and the use of physical based mismatch modeling in the prediction of mismatch errors, more adequate and realistic sizing of all transistors will result in an overall area reduction of the A/D converter. In this design the folding degree is 16, the number of folders is 64 and the interpolation level is 4. The number of folders is reduced by creating intermediate folding signals with a 4-level interpolator based on current division techniques. Current comparators detect the zero-crossing between the differential folder output currents. The outputs of the comparators deliver a cyclic thermometer code. The digital synthesis part for decoding and error correction building blocks is a standardized digital standard cell design. The basic building blocks in the target architecture were designed in 0.35μ CMOS technology; they are suitable for topological reuse and are in an automated way downscaled into a 0.18μ CMOS technology.

  11. Temperature compensated current source

    NASA Technical Reports Server (NTRS)

    Breuer, D. R. (Inventor)

    1971-01-01

    A current source was designed which is substantially independent of variations of temperature. The current source may be made either to have a linear dependence upon changes of temperature or, by the simple addition of a resistor, may be made substantially independent of temperature variations. Since the current source consists only of transistors of one conductivity type and resistors, it is ideally suited for manufacture in the form of a monolithic integrated circuit.

  12. Differential Current Source

    NASA Technical Reports Server (NTRS)

    Sutton, John F.

    1992-01-01

    Circuit acts as voltage-controlled current source having high-impedance floating differential output. Maintains commanded current in load, regardless of changes in load impedance and regardless of any common-mode voltages on load. Provides constant excitation current to germanium resistance thermometer or other transducer, output voltage of which sensed by differential voltage amplifier.

  13. Current and Future Challenges in Radiation Effects on CMOS Electronics

    NASA Astrophysics Data System (ADS)

    Dodd, P. E.; Shaneyfelt, M. R.; Schwank, J. R.; Felix, J. A.

    2010-08-01

    Advances in microelectronics performance and density continue to be fueled by the engine of Moore's law. Although lately this engine appears to be running out of steam, recent developments in advanced technologies have brought about a number of challenges and opportunities for their use in radiation environments. For example, while many advanced CMOS technologies have generally shown improving total dose tolerance, single-event effects continue to be a serious concern for highly scaled technologies. In this paper, we examine the impact of recent developments and the challenges they present to the radiation effects community. Topics covered include the impact of technology scaling on radiation response and technology challenges for both total dose and single-event effects. We include challenges for hardening and mitigation techniques at the nanometer scale. Recent developments leading to hardness assurance challenges are covered. Finally, we discuss future radiation effects challenges as the electronics industry looks beyond Moore's law to alternatives to traditional CMOS technologies.

  14. Voltage controlled current source

    DOEpatents

    Casne, Gregory M.

    1992-01-01

    A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

  15. Selected Current Data Sources.

    ERIC Educational Resources Information Center

    DeBrock, Larry M.

    1987-01-01

    Lists 55 free or inexpensive periodicals which may be used to provide current data for undergraduate economics courses. The list is divided into standard sources, federal reserve publications, selected bank newsletters, selected government newsletters, selected not-for-profit institutions, and miscellaneous. (JDH)

  16. A high current gain gate-controlled lateral bipolar junction transistor with 90 nm CMOS technology for future RF SoC applications

    NASA Astrophysics Data System (ADS)

    Chen, Shuo-Mao; Fang, Yean-Kuen; Yeh, Wen-Kuan; Lee, I. C.; Chiang, Yen-Ting

    2008-08-01

    A CMOS-compatible gate-controlled lateral BJT (GC-LBJT) was prepared with a conventional 90 nm CMOS technology for radio frequency system-on-chip (RF SoC) applications. The emitter injection efficiency and the doping profile in P-well were optimized by properly controlling source, drain, and well implants. Consequently, the GC-LBJT with a gate length of 0.15 μm can achieve a current gain over 2000 and 17/19 GHz for the fT/fmax, respectively, which are 1000%, 200%, and 60% improvements in current gain, fT and fmax, respectively as compared to the LBJT reported previously.

  17. A CMOS current-mode log(x) and log(1/x) functions generator

    NASA Astrophysics Data System (ADS)

    Al-Absi, Munir A.; Al-Tamimi, Karama M.

    2014-08-01

    A novel Complementary Metal Oxide Semiconductor (CMOS) current-mode low-voltage and low-power controllable logarithmic function circuit is presented. The proposed design utilises one Operational Transconductance Amplifier (OTA) and two PMOS transistors biased in weak inversion region. The proposed design provides high dynamic range, controllable amplitude, high accuracy and is insensitive to temperature variations. The circuit operates on a ±0.6 V power supply and consumes 0.3 μW. The functionality of the proposed circuit was verified using HSPICE with 0.35 μm 2P4M CMOS process technology.

  18. High current ion source

    DOEpatents

    Brown, Ian G.; MacGill, Robert A.; Galvin, James E.

    1990-01-01

    An ion source utilizing a cathode and anode for producing an electric arc therebetween. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma leaves the generation region and expands through another regon. The density profile of the plasma may be flattened using a magnetic field formed within a vacuum chamber. Ions are extracted from the plasma to produce a high current broad on beam.

  19. A novel pixel design with hybrid type isolation scheme for low dark current in CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Choi, Sung Ho; Kim, Yi Tae; Oh, Min Seok; Park, Young Hwan; Cho, Jeong Jin; Jang, Young Heub; Han, Hyung Jun; Choi, Jong Won; Park, Ho Woo; Jung, Sang Il; Oh, Hoon Sang; Ahn, Jung Chak; Goto, Hiroshige; Choi, Chi Young; Roh, Yonghan

    2013-02-01

    New isolation scheme for CMOS image sensor pixel is proposed and its improved dark current performance is reported. It is well known that shallow trench isolation (STI) is one of major sources of dark current in imager pixel due to the existence of interfacial defects at STI/Si interface. On the account STI-free structure over the whole pixel area was previously reported for reducing dark current. As the size of pixel pitch is shrunk, however, it becomes increasingly difficult to isolate in-pixel transistors electrically without STI. In this work, we implemented hybrid type isolation scheme of removing STI around photodiode to suppress the dark current and remaining STI near transistors to guarantee the electrical isolation of transistors in pixel. It was successfully achieved that the dark current was significantly reduced by removing the STI around the photodiode together with normal operation of in-pixel transistors.

  20. 10-bit segmented current steering DAC in 90nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Bringas, R., Jr.; Dy, F.; Gerasta, O. J.

    2015-06-01

    This special project presents a 10-Bit 1Gs/s 1.2V/3.3V Digital-to-Analog Converter using1 Poly 9 Metal SAED 90-nm CMOS Technology intended for mixed-signal and power IC applications. To achieve maximum performance with minimum area, the DAC has been implemented in 6+4 Segmentation. The simulation results show a static performance of ±0.56 LSB INL and ±0.79 LSB DNL with a total layout chip area of 0.683 mm2.The segmented architecture is implemented using two sub DAC's, which are the LSB and MSB section with certain number bits. The DAC is designed using 4-BitBinary Weighted DAC for the LSB section and 6-BitThermometer-coded DAC for the MSB section. The thermometer-coded architecture provides the most optimized results in terms of linearity through reducing the clock feed-through effect especially in hot switching between multiple transistors. The binary- weighted architecture gives better linearity output in higher frequencies with better saturation in current sources.

  1. A combined noise analysis and power supply current based testing of CMOS analog integrated circuits

    NASA Astrophysics Data System (ADS)

    Srivastava, Ashok; Pulendra, Vani K.; Yellampalli, Siva

    2005-05-01

    A technique integrating the noise analysis based testing and the conventional power supply current testing of CMOS analog integrated circuits is presented for bridging type faults due to manufacturing defects. The circuit under test (CUT) is a CMOS amplifier designed for operation at +/- 2.5 V and implemented in 1.5 μm CMOS process. The faults simulating possible manufacturing defects have been introduced using the fault injection transistors. The amplifier circuit is analyzed and simulated in SPICE for its performance with and without fault injections. The faults in the CUT are identified by observing the variation in the equivalent noise voltage at the output of CUT. In power supply current testing, the current (IPS) through the power supply voltage, VDD is measured under the application of an AC input stimulus. The effect of parametric variation is taken into consideration by determining the tolerance limit using the Monte-Carlo analysis. The fault is identified if the power supply current, IPS lies outside the deviation given by Monte-Carlo analysis. Simulation results are in close agreement with the corresponding experimental values.

  2. Monolithic integration of GMR sensors for standard CMOS-IC current sensing

    NASA Astrophysics Data System (ADS)

    De Marcellis, A.; Reig, C.; Cubells-Beltrán, M.-D.; Madrenas, J.; Santos, J. D.; Cardoso, S.; Freitas, P. P.

    2017-09-01

    In this work we report on the development of Giant Magnetoresistive (GMR) sensors for off-line current measurements in standard integrated circuits. An ASIC has been specifically designed and fabricated in the well-known AMS-0.35 μm CMOS technology, including the electronic circuitry for sensor interfacing. It implements an oscillating circuit performing a voltage-to-frequency conversion. Subsequently, a fully CMOS-compatible low temperature post-process has been applied for depositing the GMR sensing devices in a full-bridge configuration onto the buried current straps. Sensitivity and resolution of these sensors have been investigated achieving experimental results that show a detection sensitivity of about 100 Hz/mA, with a resolution of about 5 μA.

  3. Source/drain technologies for the scaling of nanoscale CMOS device

    NASA Astrophysics Data System (ADS)

    Song, Yi; Zhou, Huajie; Xu, Qiuxia

    2011-02-01

    Continuous shrinking CMOS device into 21 nm technology node is facing fundamental challenges. The International Technology Roadmap for Semiconductors (ITRS) forecasts specific requirements to realize acceptable CMOS performance for the semiconductor industry. The innovations of various source/drain technologies are considered to be indispensable for the continuous scaling of CMOS device due to the requirements of high-performance and effective suppression of short channel effects. One of the key points is to realize ultra-shallow junction with steep concentration profile and low resistivity. There are many innovative solutions including advanced doping technologies and annealing technologies for ultra-shallow junction formation. Additionally, new source/drain structures such as raised source/drain and Schottky barrier metal source/drain, and advanced silicidation technologies also serve as the important options. The state-of-the-arts of these new technologies are extensively discussed from the view point of technical innovation and performance gain. Source/drain technologies are promising and active areas of device research down to 21 nm technology node and even beyond.

  4. Gathering effect on dark current for CMOS fully integrated-, PIN-photodiodes

    NASA Astrophysics Data System (ADS)

    Teva, Jordi; Jonak-Auer, Ingrid; Schrank, Franz; Kraft, Jochen; Siegert, Joerg; Wachmann, Ewald

    2010-02-01

    PIN photodiodes are semiconductor devices widely used in a huge range of applications, such as photoconductors, charge-coupled devices, and pulse oximeters. The possibility to combine and to integrate the fabrication of the sensor with its signal conditioning circuitry in a CMOS process flow opens the window to device miniaturization enhancing its properties and lowering the production and assembly costs. This paper presents the design and characterization of silicon based PIN photodiodes integrated in a CMOS commercial process. A high-resistivity, low impurity float zone substrate is chosen as the start material for the PIN photodiode array fabrication in order to fabricate devices with a minimum dark current. The photodiodes in the array are isolated by a guard ring consisting of a n+-p+ diffusions. However, the introduction of the guard ring design, necessary for photodiode-to-photodiode isolation, leads to an increase of the photodiodes dark current. In this article, the new parasitic term on the dark current is identified, formulated, modelled and experimental proven and has finally been used for an accurate design of the guard ring.

  5. A High Performance CMOS Current Mirror Circuit with Neuron MOSFETs and a Transimpedance Amplifier

    NASA Astrophysics Data System (ADS)

    Shimizu, Akio; Ishikawa, Yohei; Fukai, Sumio; Aikawa, Masayoshi

    In this paper, we propose a high accuracy current mirror circuit suitable for a low-voltage operation. The proposed circuit has a novel negative feedback that is composed of neuron MOSFETs and a transimpedance amplifier. As a result, the proposed circuit achieves a high accuracy current mirror circuit. At the same time, the proposed circuit monitors an error current by a low voltage because the negative feedback operates in a current-mode. The performance of the proposed circuit is evaluated using HSPICE simulation with On-Semiconductor 1.48μm CMOS device parameters. Simulation results show that the output resistance of the proposed circuit is 5.79[GΩ] and minimum operating range is 0.3[V].

  6. A 14-bit 250-MS/s current-steering CMOS digital-to-analog converter

    NASA Astrophysics Data System (ADS)

    Xueqing, Li; Hua, Fan; Qi, Wei; Zhen, Xu; Jianan, Liu; Huazhong, Yang

    2013-08-01

    A 14-bit 250-MS/s current-steering digital-to-analog converter (DAC) was fabricated in a 0.13 μm CMOS process. In conventional high-speed current-steering DACs, the spurious-free dynamic range (SFDR) is limited by nonlinear distortions in the code-dependent switching glitches. In this paper, the bottleneck is mitigated by the time-relaxed interleaving digital-random-return-to-zero (TRI-DRRZ). Under 250-MS/s sampling rate, the measured SFDR is 86.2 dB at 5.5-MHz signal frequency and 77.8 dB up to 122 MHz. The DAC occupies an active area of 1.58 mm2 and consumes 226 mW from a mixed power supply of 1.2/2.5 V.

  7. A new high-performance CMOS fully differential second-generation current conveyor with application example of biquad filter realisation

    NASA Astrophysics Data System (ADS)

    Kaçar, Fırat; Metin, Bilgin; Kuntman, Hakan; Cicekoglu, Oguzhan

    2010-05-01

    In this article, a new complementary metal oxide semiconductor (CMOS) high-performance fully differential second-generation current conveyor (FDCCII) implementation is proposed. The presented FDCCII provides high-output impedance at terminals Z+ and Z-, good linearity and excellent output-input current gain accuracy. Also, the proposed FDCCII circuit operates at a supply voltage of ±1.3 V. The applications of the FDCCII to realise voltage-mode multifunction filters are given. Simulations are performed using TSMC CMOS 0.35-μm technology to verify theoretical results.

  8. Biasing, operation and parasitic current limitation in single device equivalent to CMOS, and other semiconductor systems

    DOEpatents

    Welch, James D.

    2003-09-23

    Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of applied gate voltage field induced carriers in essentially intrinsic, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at substantially equal doping levels, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at different doping levels, and containing a single metallurgical doping type, and functional combinations thereof. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents utilizing material(s) which form rectifying junctions with both N and P-type semiconductor whether metallurigically or field induced.

  9. Ultracompact Microwatt CMOS Current Readout With Picoampere Noise and Kilohertz Bandwidth for Biosensor Arrays.

    PubMed

    Li, Haitao; Parsnejad, Sina; Ashoori, Ehsan; Thompson, Cort; Purcell, Erin K; Mason, Andrew J

    2017-10-05

    High-density on-chip electrochemical biosensor arrays are advancing toward a crucial role in health monitoring and development of new medicines and medical treatments. Nanopore and ion channel based sensors especially have great potential but present demanding resolution/speed/power/area requirements on instrumentation circuits. This paper presents a pixel-level current readout circuit and new group-cluster architecture to address the circuit challenges in high-performance biosensor arrays. Fabricated in 0.5 μm CMOS, this electrochemical voltammetry circuit achieves 7.2 pA[Formula: see text] noise in an 11.5-kHz bandwidth and only consumes 21-μW power and 0.06 mm2 area per readout channel. Cyclic voltammetry experiments in a potassium ferricyanide solution and patch-clamp whole-cell experiments were performed to validate the circuit's feasibility for electrochemical biosensor applications.

  10. Self-amplified CMOS image sensor using a current-mode readout circuit

    NASA Astrophysics Data System (ADS)

    Santos, Patrick M.; de Lima Monteiro, Davies W.; Pittet, Patrick

    2014-05-01

    The feature size of the CMOS processes decreased during the past few years and problems such as reduced dynamic range have become more significant in voltage-mode pixels, even though the integration of more functionality inside the pixel has become easier. This work makes a contribution on both sides: the possibility of a high signal excursion range using current-mode circuits together with functionality addition by making signal amplification inside the pixel. The classic 3T pixel architecture was rebuild with small modifications to integrate a transconductance amplifier providing a current as an output. The matrix with these new pixels will operate as a whole large transistor outsourcing an amplified current that will be used for signal processing. This current is controlled by the intensity of the light received by the matrix, modulated pixel by pixel. The output current can be controlled by the biasing circuits to achieve a very large range of output signal levels. It can also be controlled with the matrix size and this permits a very high degree of freedom on the signal level, observing the current densities inside the integrated circuit. In addition, the matrix can operate at very small integration times. Its applications would be those in which fast imaging processing, high signal amplification are required and low resolution is not a major problem, such as UV image sensors. Simulation results will be presented to support: operation, control, design, signal excursion levels and linearity for a matrix of pixels that was conceived using this new concept of sensor.

  11. A high linearity current mode second IF CMOS mixer for a DRM/DAB receiver

    NASA Astrophysics Data System (ADS)

    Jian, Xu; Zheng, Zhou; Yiqiang, Wu; Zhigong, Wang; Jianping, Chen

    2015-05-01

    A passive current switch mixer was designed for the second IF down-conversion in a DRM/DAB receiver. The circuit consists of an input transconductance stage, a passive current switching stage, and a current amplifier stage. The input transconductance stage employs a self-biasing current reusing technique, with a resistor shunt feedback to increase the gain and output impedance. A dynamic bias technique is used in the switching stage to ensure the stability of the overdrive voltage versus the PVT variations. A current shunt feedback is introduced to the conventional low-voltage second-generation fully balanced multi-output current converter (FBMOCCII), which provides very low input impedance and high output impedance. With the circuit working in current mode, the linearity is effectively improved with low supply voltages. Especially, the transimpedance stage can be removed, which simplifies the design considerably. The design is verified with a SMIC 0.18 μm RF CMOS process. The measurement results show that the voltage conversation gain is 1.407 dB, the NF is 16.22 dB, and the IIP3 is 4.5 dBm, respectively. The current consumption is 9.30 mA with a supply voltage of 1.8 V. This exhibits a good compromise among the gain, noise, and linearity for the second IF mixer in DRM/DAB receivers. Project supported by the National Natural Science Foundation of China (No. 61306069), and the National High Technology Research and Development Program of China (No. 2011AA010301).

  12. Kernel current source density method.

    PubMed

    Potworowski, Jan; Jakuczun, Wit; Lȩski, Szymon; Wójcik, Daniel

    2012-02-01

    Local field potentials (LFP), the low-frequency part of extracellular electrical recordings, are a measure of the neural activity reflecting dendritic processing of synaptic inputs to neuronal populations. To localize synaptic dynamics, it is convenient, whenever possible, to estimate the density of transmembrane current sources (CSD) generating the LFP. In this work, we propose a new framework, the kernel current source density method (kCSD), for nonparametric estimation of CSD from LFP recorded from arbitrarily distributed electrodes using kernel methods. We test specific implementations of this framework on model data measured with one-, two-, and three-dimensional multielectrode setups. We compare these methods with the traditional approach through numerical approximation of the Laplacian and with the recently developed inverse current source density methods (iCSD). We show that iCSD is a special case of kCSD. The proposed method opens up new experimental possibilities for CSD analysis from existing or new recordings on arbitrarily distributed electrodes (not necessarily on a grid), which can be obtained in extracellular recordings of single unit activity with multiple electrodes.

  13. A reliable and controllable graphene doping method compatible with current CMOS technology and the demonstration of its device applications

    NASA Astrophysics Data System (ADS)

    Kim, Seonyeong; Shin, Somyeong; Kim, Taekwang; Du, Hyewon; Song, Minho; Kim, Ki Soo; Cho, Seungmin; Lee, Sang Wook; Seo, Sunae

    2017-04-01

    The modulation of charge carrier concentration allows us to tune the Fermi level (E F) of graphene thanks to the low electronic density of states near the E F. The introduced metal oxide thin films as well as the modified transfer process can elaborately maneuver the amounts of charge carrier concentration in graphene. The self-encapsulation provides a solution to overcome the stability issues of metal oxide hole dopants. We have manipulated systematic graphene p-n junction structures for electronic or photonic application-compatible doping methods with current semiconducting process technology. We have demonstrated the anticipated transport properties on the designed heterojunction devices with non-destructive doping methods. This mitigates the device architecture limitation imposed in previously known doping methods. Furthermore, we employed E F-modulated graphene source/drain (S/D) electrodes in a low dimensional transition metal dichalcogenide field effect transistor (TMDFET). We have succeeded in fulfilling n-type, ambipolar, or p-type field effect transistors (FETs) by moving around only the graphene work function. Besides, the graphene/transition metal dichalcogenide (TMD) junction in either both p- and n-type transistor reveals linear voltage dependence with the enhanced contact resistance. We accomplished the complete conversion of p-/n-channel transistors with S/D tunable electrodes. The E F modulation using metal oxide facilitates graphene to access state-of-the-art complimentary-metal-oxide-semiconductor (CMOS) technology.

  14. A CMOS Current Steering Neurostimulation Array With Integrated DAC Calibration and Charge Balancing.

    PubMed

    Greenwald, Elliot; Maier, Christoph; Wang, Qihong; Beaulieu, Robert; Etienne-Cummings, Ralph; Cauwenberghs, Gert; Thakor, Nitish

    2017-04-01

    An 8-channel current steerable, multi-phasic neural stimulator with on-chip current DAC calibration and residue nulling for precise charge balancing is presented. Each channel consists of two sub-binary radix DACs followed by wide-swing, high output impedance current buffers providing time-multiplexed source and sink outputs for anodic and cathodic stimulation. A single integrator is shared among channels and serves to calibrate DAC coefficients and to closely match the anodic and cathodic stimulation phases. Following calibration, the differential non-linearity is within ±0.3 LSB at 8-bit resolution, and the two stimulation phases are matched within 0.3%. Individual control in digital programming of stimulation coefficients across the array allows altering the spatial profile of current stimulation for selection of stimulation targets by current steering. Combined with the self-calibration and current matching functions, the current steering capabilities integrated on-chip support use in fully implanted neural interfaces with autonomous operation for and adaptive stimulation under variations in electrode and tissue conditions. As a proof-of-concept we applied current steering stimulation through a multi-channel cuff electrode on the sciatic nerve of a rat.

  15. Tunnel FinFET CMOS inverter with very low short-circuit current for ultralow-power Internet of Things application

    NASA Astrophysics Data System (ADS)

    Morita, Yukinori; Fukuda, Koichi; Liu, Yongxun; Mori, Takahiro; Mizubayashi, Wataru; O'uchi, Shin-ichi; Fuketa, Hiroshi; Otsuka, Shintaro; Migita, Shinji; Masahara, Meishoku; Endo, Kazuhiko; Ota, Hiroyuki; Matsukawa, Takashi

    2017-04-01

    We have demonstrated the operation of a CMOS inverter consisting of Si tunnel FinFETs. Both p- and n-type tunnel FinFETs are successfully fabricated and operated on the same SOI wafer. The current mismatch between p- and n-type tunnel FETs is compensated by tuning the number of fin channels. Very low short-circuit current and clear voltage input-output characteristics are obtained. The thin epitaxial channel in the tunnel FinFETs effectively increases the drain current and accordingly reduces the drain capacitance, which could help high-performance tunnel FET CMOS inverter operation.

  16. A 200 mV low leakage current subthreshold SRAM bitcell in a 130 nm CMOS process

    NASA Astrophysics Data System (ADS)

    Na, Bai; Baitao, Lü

    2012-06-01

    A low leakage current subthreshold SRAM in 130 nm CMOS technology is proposed for ultra low voltage (200 mV) applications. Almost all of the previous subthreshold works ignore the leakage current in both active and standby modes. To minimize leakage, a self-adaptive leakage cut off scheme is adopted in the proposed design without any extra dynamic energy dissipation or performance penalty. Combined with buffering circuit and reconfigurable operation, the proposed design ensures both read and standby stability without deteriorating writability in the subthreshold region. Compared to the referenced subthreshold SRAM bitcell, the proposed bitcell shows: (1) a better critical state noise margin, and (2) smaller leakage current in both active and standby modes. Measurement results show that the proposed SRAM functions well at a 200 mV supply voltage with 0.13 μW power consumption at 138 kHz frequency.

  17. Regenerative switching CMOS system

    DOEpatents

    Welch, James D.

    1998-01-01

    Complementary Metal Oxide Semiconductor (CMOS) Schottky barrier Field Effect Transistor systems, which are a seriesed combination of N and P-Channel MOSFETS, in which Source Schottky barrier junctions of the N and P-Channel Schottky barrier MOSFETS are electically interconnected, (rather than the Drains as in conventional diffused junction CMOS), which Schottky barrier MOSFET system demonstrates Regenerative Inverting Switching Characteristics in use are disclosed. Both the N and P-Channel Schottky barrier MOSFET devices are unique in that they provide operational Drain Current vs. Drain to Source voltage as a function of Gate voltage only where the polarities of the Drain voltage and Gate voltage are opposite, referenced to the Source as a common terminal, and where the polarity of the voltage applied to the Gate is appropriate to cause Channel inversion. Experimentally derived results which demonstrate and verify the operation of N and P-Channel Schottky barrier MOSFETS actually fabricated on P and N-type Silicon respectively, by a common procedure using vacuum deposited Chromium as a Schottky barrier forming metal, are also provided.

  18. Regenerative switching CMOS system

    DOEpatents

    Welch, J.D.

    1998-06-02

    Complementary Metal Oxide Semiconductor (CMOS) Schottky barrier Field Effect Transistor systems, which are a series combination of N and P-Channel MOSFETS, in which Source Schottky barrier junctions of the N and P-Channel Schottky barrier MOSFETS are electrically interconnected, (rather than the Drains as in conventional diffused junction CMOS), which Schottky barrier MOSFET system demonstrates Regenerative Inverting Switching Characteristics in use are disclosed. Both the N and P-Channel Schottky barrier MOSFET devices are unique in that they provide operational Drain Current vs. Drain to Source voltage as a function of Gate voltage only where the polarities of the Drain voltage and Gate voltage are opposite, referenced to the Source as a common terminal, and where the polarity of the voltage applied to the Gate is appropriate to cause Channel inversion. Experimentally derived results which demonstrate and verify the operation of N and P-Channel Schottky barrier MOSFETS actually fabricated on P and N-type Silicon respectively, by a common procedure using vacuum deposited Chromium as a Schottky barrier forming metal, are also provided. 14 figs.

  19. Simple, high current, antimony ion source.

    PubMed

    Sugiura, H

    1979-01-01

    A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 muA at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6x10(-4) Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8x10(-9) and 1.8x10(11) cm(-3), respectively.

  20. CMOS temperature sensor using a resistively degenerated common-source amplifier biased by an adjustable proportional-to-absolute-temperature voltage

    NASA Astrophysics Data System (ADS)

    Wang, Ruey-Lue; Fu, Chien-Cheng; Yu, Chi; Hao, Yi-Fan; Shi, Jian-Liang; Lin, Chen-Fu; Liao, Hsin-Hao; Tsai, Hann-Huei; Juang, Ying-Zong

    2014-01-01

    A high-linearity CMOS temperature sensor with pulse output is presented. The temperature core is a resistively degenerated common-source amplifier which gate is biased by a proportional-to-absolute-temperature (PTAT) voltage generator. The source resistor is made of polysilicon which resistance has a PTAT characteristic. The current flowing through the resistor exhibits a PTAT characteristic with high linearity of 99.99% at least for a temperature range from 0 to 125 °C. The PTAT voltage generator can be adjusted by a bias voltage Vb and hence the PTAT current can also be adjusted by the Vb. The PTAT current is mirrored to an added current controlled oscillator which output pulse frequencies also exhibit a PTAT characteristic. For the chip using the 0.35 µm process, the plots of measured pulse frequencies against temperature exhibit the sensitivity of 2.30 to 2.24 kHz/°C with linearity of more than 99.99% at the Vb of 1 to 1.2 V.

  1. Pixel pitch and particle energy influence on the dark current distribution of neutron irradiated CMOS image sensors.

    PubMed

    Belloir, Jean-Marc; Goiffon, Vincent; Virmontois, Cédric; Raine, Mélanie; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Molina, Romain; Magnan, Pierre; Gilard, Olivier

    2016-02-22

    The dark current produced by neutron irradiation in CMOS Image Sensors (CIS) is investigated. Several CIS with different photodiode types and pixel pitches are irradiated with various neutron energies and fluences to study the influence of each of these optical detector and irradiation parameters on the dark current distribution. An empirical model is tested on the experimental data and validated on all the irradiated optical imagers. This model is able to describe all the presented dark current distributions with no parameter variation for neutron energies of 14 MeV or higher, regardless of the optical detector and irradiation characteristics. For energies below 1 MeV, it is shown that a single parameter has to be adjusted because of the lower mean damage energy per nuclear interaction. This model and these conclusions can be transposed to any silicon based solid-state optical imagers such as CIS or Charged Coupled Devices (CCD). This work can also be used when designing an optical imager instrument, to anticipate the dark current increase or to choose a mitigation technique.

  2. A multiphase clock generation based on DLL for source synchronous receiver in 65nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Li, Zhentao; Wang, Ziqiang; Jia, Chen; Huang, Ke; Zhang, Chun; Zheng, Xuqiang; Wang, Zhihua

    2013-03-01

    This paper presents a multiphase clock generation circuit (MPCG) using delay locked loop (DLL). In order to achieve process independence, fixed bandwidth to operating frequency ratio, broad tuning range, and low jitter, the DLL design is based on self-biased technique augmented with jitter attenuation technique, which can achieve precise delay equal to the input reference clock period. Simulated in 65nm CMOS technology, the MPCG achieves an operating frequency range of 1.8GHz to 4GHz. And the MPCG will generate eight clocks evenly spaced by 45 degrees. At 2.5GHz, its peak to peak jitter with quiescent supply is 10ps, and its power consumption is 11mW.

  3. Beam current controller for laser ion source

    DOEpatents

    Okamura, Masahiro

    2014-10-28

    The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

  4. A wideband current-commutating passive mixer for multi-standard receivers in a 0.18 μm CMOS

    NASA Astrophysics Data System (ADS)

    Kuan, Bao; Xiangning, Fan; Wei, Li; Zhigong, Wang

    2013-01-01

    This paper reports a wideband passive mixer for direct conversion multi-standard receivers. A brief comparison between current-commutating passive mixers and active mixers is presented. The effect of source and load impedance on the linearity of a mixer is analyzed. Specially, the impact of the input impedance of the transimpedance amplifier (TIA), which acts as the load impedance of a mixer, is investigated in detail. The analysis is verified by a passive mixer implemented with 0.18 μm CMOS technology. The circuit is inductorless and can operate over a broad frequency range. On wafer measurements show that, with radio frequency (RF) ranges from 700 MHz to 2.3 GHz, the mixer achieves 21 dB of conversion voltage gain with a -1 dB intermediate frequency (IF) bandwidth of 10 MHz. The measured IIP3 is 9 dBm and the measured double-sideband noise figure (NF) is 10.6 dB at 10 MHz output. The chip occupies an area of 0.19 mm2 and drains a current of 5.5 mA from a 1.8 V supply.

  5. Centroid Position as a Function of Total Counts in a Windowed CMOS Image of a Point Source

    SciTech Connect

    Wurtz, R E; Olivier, S; Riot, V; Hanold, B J; Figer, D F

    2010-05-27

    We obtained 960,200 22-by-22-pixel windowed images of a pinhole spot using the Teledyne H2RG CMOS detector with un-cooled SIDECAR readout. We performed an analysis to determine the precision we might expect in the position error signals to a telescope's guider system. We find that, under non-optimized operating conditions, the error in the computed centroid is strongly dependent on the total counts in the point image only below a certain threshold, approximately 50,000 photo-electrons. The LSST guider camera specification currently requires a 0.04 arcsecond error at 10 Hertz. Given the performance measured here, this specification can be delivered with a single star at 14th to 18th magnitude, depending on the passband.

  6. High Performance CMOS Light Detector with Dark Current Suppression in Variable-Temperature Systems

    PubMed Central

    Lin, Wen-Sheng; Sung, Guo-Ming; Lin, Jyun-Long

    2016-01-01

    This paper presents a dark current suppression technique for a light detector in a variable-temperature system. The light detector architecture comprises a photodiode for sensing the ambient light, a dark current diode for conducting dark current suppression, and a current subtractor that is embedded in the current amplifier with enhanced dark current cancellation. The measured dark current of the proposed light detector is lower than that of the epichlorohydrin photoresistor or cadmium sulphide photoresistor. This is advantageous in variable-temperature systems, especially for those with many infrared light-emitting diodes. Experimental results indicate that the maximum dark current of the proposed current amplifier is approximately 135 nA at 125 °C, a near zero dark current is achieved at temperatures lower than 50 °C, and dark current and temperature exhibit an exponential relation at temperatures higher than 50 °C. The dark current of the proposed light detector is lower than 9.23 nA and the linearity is approximately 1.15 μA/lux at an external resistance RSS = 10 kΩ and environmental temperatures from 25 °C to 85 °C. PMID:28025530

  7. High Performance CMOS Light Detector with Dark Current Suppression in Variable-Temperature Systems.

    PubMed

    Lin, Wen-Sheng; Sung, Guo-Ming; Lin, Jyun-Long

    2016-12-23

    This paper presents a dark current suppression technique for a light detector in a variable-temperature system. The light detector architecture comprises a photodiode for sensing the ambient light, a dark current diode for conducting dark current suppression, and a current subtractor that is embedded in the current amplifier with enhanced dark current cancellation. The measured dark current of the proposed light detector is lower than that of the epichlorohydrin photoresistor or cadmium sulphide photoresistor. This is advantageous in variable-temperature systems, especially for those with many infrared light-emitting diodes. Experimental results indicate that the maximum dark current of the proposed current amplifier is approximately 135 nA at 125 °C, a near zero dark current is achieved at temperatures lower than 50 °C, and dark current and temperature exhibit an exponential relation at temperatures higher than 50 °C. The dark current of the proposed light detector is lower than 9.23 nA and the linearity is approximately 1.15 μA/lux at an external resistance RSS = 10 kΩ and environmental temperatures from 25 °C to 85 °C.

  8. Light sources based on semiconductor current filaments

    DOEpatents

    Zutavern, Fred J.; Loubriel, Guillermo M.; Buttram, Malcolm T.; Mar, Alan; Helgeson, Wesley D.; O'Malley, Martin W.; Hjalmarson, Harold P.; Baca, Albert G.; Chow, Weng W.; Vawter, G. Allen

    2003-01-01

    The present invention provides a new type of semiconductor light source that can produce a high peak power output and is not injection, e-beam, or optically pumped. The present invention is capable of producing high quality coherent or incoherent optical emission. The present invention is based on current filaments, unlike conventional semiconductor lasers that are based on p-n junctions. The present invention provides a light source formed by an electron-hole plasma inside a current filament. The electron-hole plasma can be several hundred microns in diameter and several centimeters long. A current filament can be initiated optically or with an e-beam, but can be pumped electrically across a large insulating region. A current filament can be produced in high gain photoconductive semiconductor switches. The light source provided by the present invention has a potentially large volume and therefore a potentially large energy per pulse or peak power available from a single (coherent) semiconductor laser. Like other semiconductor lasers, these light sources will emit radiation at the wavelength near the bandgap energy (for GaAs 875 nm or near infra red). Immediate potential applications of the present invention include high energy, short pulse, compact, low cost lasers and other incoherent light sources.

  9. Comparison of a new integrated current source with the modified Howland circuit for EIT applications.

    PubMed

    Hong, Hongwei; Rahal, Mohamad; Demosthenous, Andreas; Bayford, Richard H

    2009-10-01

    Multi-frequency electrical impedance tomography (MF-EIT) systems require current sources that are accurate over a wide frequency range (1 MHz) and with large load impedance variations. The most commonly employed current source design in EIT systems is the modified Howland circuit (MHC). The MHC requires tight matching of resistors to achieve high output impedance and may suffer from instability over a wide frequency range in an integrated solution. In this paper, we introduce a new integrated current source design in CMOS technology and compare its performance with the MHC. The new integrated design has advantages over the MHC in terms of power consumption and area. The output current and the output impedance of both circuits were determined through simulations and measurements over the frequency range of 10 kHz to 1 MHz. For frequencies up to 1 MHz, the measured maximum variation of the output current for the integrated current source is 0.8% whereas for the MHC the corresponding value is 1.5%. Although the integrated current source has an output impedance greater than 1 MOmega up to 1 MHz in simulations, in practice, the impedance is greater than 160 kOmega up to 1 MHz due to the presence of stray capacitance.

  10. A Low-Noise CMOS THz Imager Based on Source Modulation and an In-Pixel High-Q Passive Switched-Capacitor N-Path Filter.

    PubMed

    Boukhayma, Assim; Dupret, Antoine; Rostaing, Jean-Pierre; Enz, Christian

    2016-03-03

    This paper presents the first low noise complementary metal oxide semiconductor (CMOS) deletedCMOS terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31 × 31 focal plane array has been fully integrated in a 0 . 13 μ m standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency. The filter is based on a passive switched-capacitor (SC) N-path filter combined with a continuous-time broad-band Gm-C filter. A simplified analysis that helps in designing and tuning the passive SC N-path filter is provided. The characterization of the readout chain shows that a Q factor of 100 has been achieved for the filter with a good matching between the analytical calculation and the measurement results. An input-referred noise of 0 . 2 μ V RMS has been measured. Characterization of the chip with different THz wavelengths confirms the broadband feature of the antenna and shows that this THz imager reaches a total noise equivalent power of 0 . 6 nW at 270 GHz and 0 . 8 nW at 600 GHz.

  11. An experimental study of solid source diffusion by spin on dopants and its application for minimal silicon-on-insulator CMOS fabrication

    NASA Astrophysics Data System (ADS)

    Liu, Yongxun; Koga, Kazuhiro; Khumpuang, Sommawan; Nagao, Masayoshi; Matsukawa, Takashi; Hara, Shiro

    2017-06-01

    Solid source diffusions of phosphorus (P) and boron (B) into the half-inch (12.5 mm) minimal silicon (Si) wafers by spin on dopants (SOD) have been systematically investigated and the physical-vapor-deposited (PVD) titanium nitride (TiN) metal gate minimal silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) field-effect transistors (FETs) have successfully been fabricated using the developed SOD thermal diffusion technique. It was experimentally confirmed that a low temperature oxidation (LTO) process which depresses a boron silicide layer formation is effective way to remove boron-glass in a diluted hydrofluoric acid (DHF) solution. It was also found that top Si layer thickness of SOI wafers is reduced in the SOD thermal diffusion process because of its consumption by thermal oxidation owing to the oxygen atoms included in SOD films, which should be carefully considered in the ultrathin SOI device fabrication. Moreover, normal operations of the fabricated minimal PVD-TiN metal gate SOI-CMOS inverters, static random access memory (SRAM) cells and ring oscillators have been demonstrated. These circuit level results indicate that no remarkable particles and interface traps were introduced onto the minimal wafers during the device fabrication, and the developed solid source diffusion by SOD is useful for the fabrication of functional logic gate minimal SOI-CMOS integrated circuits.

  12. HIGH CURRENT RADIO FREQUENCY ION SOURCE

    DOEpatents

    Abdelaziz, M.E.

    1963-04-01

    This patent relates to a high current radio frequency ion source. A cylindrical plasma container has a coil disposed around the exterior surface thereof along the longitudinal axis. Means are provided for the injection of an unionized gas into the container and for applying a radio frequency signal to the coil whereby a radio frequency field is generated within the container parallel to the longitudinal axis thereof to ionize the injected gas. Cathode and anode means are provided for extracting transverse to the radio frequency field from an area midway between the ends of the container along the longitudinal axis thereof the ions created by said radio frequency field. (AEC)

  13. CMOS transistor-only 8-b 4.5-Ms/s pipelined analog-to-digital converter using fully-differential current-mode circuit techniques

    NASA Astrophysics Data System (ADS)

    Wu, Chung-Yu; Chen, Chih-Cheng; Cho, Jyh-Jer

    1995-05-01

    Fully-differential current-mode circuit techniques are developed for the design of a pipelined current-mode analog-to-digital converter (IADC) in the standard CMOS digital processes. In the proposed IADC, the 1-b-per-stage architecture based on the reference nonrestoring algorithm is adopted. Thus large component ratios can be avoided and the linearity errors caused by device mismatches can be minimized. As one of the key subcircuits in the IADC, an offset-canceled high speed differential current comparator (CCMP) is proposed and analyzed. In the CCMP, the subtractions of offsets are performed in the current domain without floating capacitors. Moreover, the other key subcircuit, the current sample-and-hold amplifier (CSHA), is also developed to realize the pipeline architecture. An experimental chip for the proposed IADC has been fabricated in 0.8- micron n-well CMOS technology. Using a single 5-V power supply, the fabricated IADC can be operated at 4.5-Ms/s conversion rate with a signal-to-noise-and-distortion-ratio (SNDR) of 51 dB (effective 8.2-b) for the input signal at 453 kHz. For 8-b resolution, the fabricated IADC can be operated at 4.5-Ms/s conversion rate with both differential nonlinearity (DNL) and integral nonlinearity (INL) below +/ - 0.6 LSB. The power consumption and the active chip area are 16 mW/b and 0.73 mm(sup 2)/b, respectively.

  14. A zero-voltage switching technique for minimizing the current-source power of implanted stimulators.

    PubMed

    Çilingiroğlu, Uğur; İpek, Sercan

    2013-08-01

    The current-source power of an implanted stimulator is reduced almost to the theoretical minimum by driving the electrodes directly from the secondary port of the inductive link with a dedicated zero-voltage switching power supply. A feedback loop confined to the secondary of the inductive link adjusts the timing and conduction angle of switching to provide just the right amount of supply voltage needed for keeping the current-source voltage constant at or slightly above the compliance limit. Since drive is based on current rather than voltage, and supply-voltage update is near real-time, the quality of the current pulses is high regardless of how the electrode impedance evolves during stimulation. By scaling the switching frequency according to power demand, the technique further improves overall power consumption of the stimulator. The technique is implemented with a very simple control circuitry comprising a comparator, a Schmitt trigger and a logic gate of seven devices in addition to an on-chip switch and an off-chip capacitor. The power consumed by the proposed supply circuit itself is no larger than what the linear regulator of a conventional supply typically consumes for the same stimulation current. Still, the sum of supply and current-source power is typically between 20% and 75% of the conventional source power alone. Functionality of the proposed driver is verified experimentally on a proof-of-concept prototype built with 3.3 V devices in a 0.18 μm CMOS technology.

  15. Light-controlled biphasic current stimulator IC using CMOS image sensors for high-resolution retinal prosthesis and in vitro experimental results with rd1 mouse.

    PubMed

    Oh, Sungjin; Ahn, Jae-Hyun; Lee, Sangmin; Ko, Hyoungho; Seo, Jong Mo; Goo, Yong-Sook; Cho, Dong-il Dan

    2015-01-01

    Retinal prosthetic devices stimulate retinal nerve cells with electrical signals proportional to the incident light intensities. For a high-resolution retinal prosthesis, it is necessary to reduce the size of the stimulator pixels as much as possible, because the retinal nerve cells are concentrated in a small area of approximately 5 mm × 5 mm. In this paper, a miniaturized biphasic current stimulator integrated circuit is developed for subretinal stimulation and tested in vitro. The stimulator pixel is miniaturized by using a complementary metal-oxide-semiconductor (CMOS) image sensor composed of three transistors. Compared to a pixel that uses a four-transistor CMOS image sensor, this new design reduces the pixel size by 8.3%. The pixel size is further reduced by simplifying the stimulation-current generating circuit, which provides a 43.9% size reduction when compared to the design reported to be the most advanced version to date for subretinal stimulation. The proposed design is fabricated using a 0.35 μm bipolar-CMOS-DMOS process. Each pixel is designed to fit in a 50 μ m × 55 μm area, which theoretically allows implementing more than 5000 pixels in the 5 mm × 5 mm area. Experimental results show that a biphasic current in the range of 0 to 300 μA at 12 V can be generated as a function of incident light intensities. Results from in vitro experiments with rd1 mice indicate that the proposed method can be effectively used for retinal prosthesis with a high resolution.

  16. An On-Chip Multi-Voltage Power Converter With Leakage Current Prevention Using 0.18 μm High-Voltage CMOS Process.

    PubMed

    Lo, Yi-Kai; Chen, Kuanfu; Gad, Parag; Liu, Wentai

    2016-02-01

    In this paper, we present an on-chip multi-voltage power converter incorporating of a quad-voltage timing-control rectifier and regulators to produce ±12 V and ±1.8 V simultaneously through inductive powering. The power converter achieves a PCE of 77.3% with the delivery of more than 100 mW to the implant. The proposed rectifier adopts a two-phase start-up scheme and mixed-voltage gate controller to avoid substrate leakage current. This current cannot be prevented by the conventional dynamic substrate biasing technique when using the high-voltage CMOS process with transistor threshold voltage higher than the turn-on voltage of parasitic diodes. High power conversion efficiency is achieved by 1) substrate leakage current prevention, 2) operating all rectifying transistors as switches with boosted gate control voltages, and 3) compensating the delayed turn-on and preventing reverse leakage current of rectifying switches with the proposed look-ahead comparator. This chip occupies an area of 970 μm × 4500 μm in a 0.18 μ m 32 V HV CMOS process. The quad-voltage timing-control rectifier alone is able to output a high DC voltage at the range of [2.5 V, 25 V]. With this power converter, both bench-top experiment and in-vivo power link test using a rat model were validated.

  17. Ion diffusion may introduce spurious current sources in Current-Source Density (CSD) analysis.

    PubMed

    Halnes, Geir; Mäki-Marttunen, Tuomo; Pettersen, Klas H; Andreassen, Ole A; Einevoll, Gaute T

    2017-03-15

    Current-source density (CSD) analysis is a well-established method for analyzing recorded ocal field potentials (LFPs), that is, the low-frequency part of extracellular potentials. Standard CSD theory is based on the assumption that all extracellular currents are purely ohmic, and thus neglects the possible impact from ionic diffusion on recorded potentials. However, it has previously been shown that in physiological conditions with large ion-concentration gradients, diffusive currents can evoke slow shifts in extracellular potentials. Using computer simulations, we here show that diffusion-evoked potential shifts can introduce errors in standard CSD analysis, and can lead to prediction of spurious current sources. Further, we show that the diffusion-evoked prediction errors can be removed by using an improved CSD estimator which accounts for concentration-dependent effects.

  18. On noise in time-delay integration CMOS image sensors

    NASA Astrophysics Data System (ADS)

    Levski, Deyan; Choubey, Bhaskar

    2016-05-01

    Time delay integration sensors are of increasing interest in CMOS processes owing to their low cost, power and ability to integrate with other circuit readout blocks. This paper presents an analysis of the noise contributors in current day CMOS Time-Delay-Integration image sensors with various readout architectures. An analysis of charge versus voltage domain readout modes is presented, followed by a noise classification of the existing Analog Accumulator Readout (AAR) and Digital Accumulator Readout (DAR) schemes for TDI imaging. The analysis and classification of existing readout schemes include, pipelined charge transfer, buffered direct injection, voltage as well as current-mode analog accumulators and all-digital accumulator techniques. Time-Delay-Integration imaging modes in CMOS processes typically use an N-number of readout steps, equivalent to the number of TDI pixel stages. In CMOS TDI sensors, where voltage domain readout is used, the requirements over speed and noise of the ADC readout chain are increased due to accumulation of the dominant voltage readout and ADC noise with every stage N. Until this day, the latter is the primary reason for a leap-back of CMOS TDI sensors as compared to their CCD counterparts. Moreover, most commercial CMOS TDI implementations are still based on a charge-domain readout, mimicking a CCD-like operation mode. Thus, having a good understanding of each noise contributor in the signal chain, as well as its magnitude in different readout architectures, is vital for the design of future generation low-noise CMOS TDI image sensors based on a voltage domain readout. This paper gives a quantitative classification of all major noise sources for all popular implementations in the literature.

  19. Resistor Extends Life Of Battery In Clocked CMOS Circuit

    NASA Technical Reports Server (NTRS)

    Wells, George H., Jr.

    1991-01-01

    Addition of fixed resistor between battery and clocked complementary metal oxide/semiconductor (CMOS) circuit reduces current drawn from battery. Basic idea to minimize current drawn from battery by operating CMOS circuit at lowest possible current consistent with use of simple, fixed off-the-shelf components. Prolongs lives of batteries in such low-power CMOS circuits as watches and calculators.

  20. A 0.06 mm2 1.0 V 2.5 mW 10 bit 250 MS/s current-steering D/A converter in 65 nm GP CMOS process

    NASA Astrophysics Data System (ADS)

    Yawei, Guo; Li, Li; Peng, Ou; Zhida, Hui; Xu, Cheng; Xiaoyang, Zeng

    2014-06-01

    A 10 bit 250 MS/s current-steering digital-to-analog converter is presented. Only standard VT core devices are available for the sake of simplicity and low cost. In order to meet the INL performance, a Monte Carlo model is built to analyze the impact of mismatch on integral nonlinearity (INL) yield with both end-point line and best-fit line. A formula is derived for the relationship of INL and output impedance. The relation of dynamic range and output impedance is also discussed. The double centroid layout is adopted for the current source array in order to mitigate the effect of electrical, process, and temperature gradient. An adapted current mirror is used to overcome the gate leakage of the current source array, which cannot be ignored in the 65 nm GP CMOS process. The digital-to-analog converter occupies 0.06 mm2, and consumes 2.5 mW from a single 1.0 V supply at 250 MS/s.

  1. Light sources currently used in photochemotherapy

    NASA Astrophysics Data System (ADS)

    Kwasńy, Mirosław; Gietka, Andrzej; Kotowski, Paweł; Mierczyk, Zygmunt

    2016-12-01

    The availability of low-cost therapeutic illuminators was one of the key factors to limit clinical use of PDT. The paper presents modern light sources which have revolutionized PDT method, contributing to its more common use. The technical parameters of different illuminators are compared. Finally, own light sources were presented and developed in Polish clinics.

  2. Current status of pacemaker power sources.

    PubMed

    Tyers, G F; Brownlee, R R

    1978-06-01

    After years during which pacers of very similar design and capabilities were provided by a small number of manufactures, many different lithium, halogen, rechargeable, and nuclear power sources are now available. The variety of chemistries, methods of construction, and sealing techniques used in the batteries of the different manufacturers is almost unlimited. This has made it necessary for physicians who implant and follow pacer to acquire a general knowledge of the field if they are to make an informed choice of pacemaker power source for implantation and if they are to manage recalls with a minimum of patient and physician trauma. More experience is required before it can be definitely determined which of the new pacer power sources will prove superior, but when coupled with well-designed, hermetically sealed pulse generators, all are capable of providing continuous pacing for at least 5 years and the 10-year pacemaker is now a probability.

  3. Thimerosal: current sources of contact in Brazil.

    PubMed

    Rocha, Vanessa Barreto; Scherrer, Maria Antonieta Rios

    2014-01-01

    Thimerosal is an organic mercury derivative found in ophthalmic solutions and certain vaccines in Brazil. Although most studies suggest the prevalence of thimerosal sensitivity to be quite high, this condition does not currently have any clinical relevance. The present article surveyed 184 Brazilian products (151 topical medications and 33 vaccines) and found that thimerosal was only present in 3 ophthalmic solutions and 5 vaccines.

  4. Thimerosal: current sources of contact in Brazil*

    PubMed Central

    Rocha, Vanessa Barreto; Scherrer, Maria Antonieta Rios

    2014-01-01

    Thimerosal is an organic mercury derivative found in ophthalmic solutions and certain vaccines in Brazil. Although most studies suggest the prevalence of thimerosal sensitivity to be quite high, this condition does not currently have any clinical relevance. The present article surveyed 184 Brazilian products (151 topical medications and 33 vaccines) and found that thimerosal was only present in 3 ophthalmic solutions and 5 vaccines. PMID:24770530

  5. Sources and Losses of Ring Current Ions

    NASA Technical Reports Server (NTRS)

    Chen, Sheng-Hsien; Fok, Mei-Ching H.; Angeloupoulos, Vassilis

    2010-01-01

    During geomagnetic quiet times, in-situ measurements of ring current energetic ions (few to few tens of keVs) from THEMIS spacecraft often exhibit multiple ion populations at discrete energies that extend from the inner magnetosphere to the magnetopause at dayside or plasma sheet at nightside. During geomagnetic storm times, the levels of fluxes as well as the mean energies of these ions elevated dramatically and the more smooth distributions in energies and distances during quiet times are disrupted into clusters of ion populations with more confined spatial extends. This reveals local plasma heating processes that might have come into play. Several processes have been proposed. Magnetotail dipolarization, sudden enhancement of field-aligned current, local current disruptions, and plasma waves are possible mechanisms to heat the ions locally as well as strong convections of energetic ions directly from the magnetotail due to reconnections. We will examine two geomagnetic storms on October 11, 2008 and July 22, 2009 to reveal possible heating mechanisms. We will analyze in-situ plasma and magnetic field measurements from THEMIS, GOES, and DMSP for the events to study the ion pitch angle distributions and magnetic field perturbations in the auroral ionosphere and inner magnetosphere where the plasma heating processes occur.

  6. A Low-Noise CMOS THz Imager Based on Source Modulation and an In-Pixel High-Q Passive Switched-Capacitor N-Path Filter

    PubMed Central

    Boukhayma, Assim; Dupret, Antoine; Rostaing, Jean-Pierre; Enz, Christian

    2016-01-01

    This paper presents the first low noise complementary metal oxide semiconductor (CMOS) terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31×31 focal plane array has been fully integrated in a 0.13μm standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency. The filter is based on a passive switched-capacitor (SC) N-path filter combined with a continuous-time broad-band Gm-C filter. A simplified analysis that helps in designing and tuning the passive SC N-path filter is provided. The characterization of the readout chain shows that a Q factor of 100 has been achieved for the filter with a good matching between the analytical calculation and the measurement results. An input-referred noise of 0.2μV RMS has been measured. Characterization of the chip with different THz wavelengths confirms the broadband feature of the antenna and shows that this THz imager reaches a total noise equivalent power of 0.6 nW at 270 GHz and 0.8 nW at 600 GHz. PMID:26950131

  7. High Current Ion Sources and Injectors for Heavy Ion Fusion

    SciTech Connect

    Kwan, Joe W.

    2005-02-15

    Heavy ion beam driven inertial fusion requires short ion beam pulses with high current and high brightness. Depending on the beam current and the number of beams in the driver system, the injector can use a large diameter surface ionization source or merge an array of small beamlets from a plasma source. In this paper, we review the scaling laws that govern the injector design and the various ion source options including the contact ionizer, the aluminosilicate source, the multicusp plasma source, and the MEVVA source.

  8. Explosive magnetic source of current with controllable output voltage

    NASA Astrophysics Data System (ADS)

    Dudai, P. V.; Zimenkov, A. A.; Ivanov, V. A.; Ivanov, E. I.; Karpov, G. V.; Polyushko, S. M.; Skobelev, A. N.; Fevralev, A. Yu.

    2015-01-01

    The paper describes a small-size explosive current source with controllable output voltage shaping a megaampere current pulse. This energy source comprises a helical explosive magnetic generator and an explosive sectionalized current opening switch and is designed to power gas-discharge chambers of the plasma focus type. Control of the output voltage of the pulsed current source is performed in such a manner that in each of the series-connected sections of the explosive current opening switch, voltage is generated with a given time shift relative to the neighboring section.

  9. The source of the Leeuwin Current seasonality

    NASA Astrophysics Data System (ADS)

    Ridgway, K. R.; Godfrey, J. S.

    2015-10-01

    The seasonal circulation around the southwestern boundary of Australia is documented using sea level anomalies from satellite altimetry. Results extrapolated to the coast agree closely with tide gauge observations indicating that seasonal altimeter fields are realistic. Monthly sea level maps identify an annual propagating wave along a waveguide extending along the shelf edge, from the Gulf of Carpentaria to southern Tasmania. The annual sea level pulse does not originate from the Pacific Ocean, as annual Pacific sea level variations are completely out of phase with signals south of the Indonesian archipelago. The presence of a phase discontinuity is demonstrated in annual sea level, temperature, and salinity observations. The origin of the Leeuwin Current seasonality is in the Gulf of Carpentaria where monsoonal winds drive a massive buildup of sea level from November to December. During December-February, a sea level "pulse" emerges from the region, and rapidly propagates poleward along the western and southern Australian boundary. In the broad shelf region centered at 19°S, an independent process forms a high sea level feature when a positive heat flux anomaly induces an annual increase in sea surface temperature which is rapidly mixed through the water column by the strong regional tides. In March, the winds relax and switch to a downwelling favorable alongshore component. In this period, the sea level pulse is essentially in a quasi-static equilibrium with the annual propagating wind systems. The change in cross-shelf sea level gradient along the 8000 km path length at the western and southern boundaries, drives the seasonal changes in the Leeuwin Current flow.

  10. Multipole expansions in the representation of current sources.

    PubMed

    Trontelj, Z; Jazbinsek, V; Erné, S N; Trahms, L

    1991-01-01

    After obtaining the measured magnetic field or its components in the form of an isofield map one has to decide which approximation to use in solving the inverse problem. A single current dipole as an equivalent current source is often used. It will be shown when this approximation fails and one possible way to improve the equivalent source description. The expansion of current multipoles is discussed up to the second order. The localization of an equivalent current source in this case is considered. The application of this type of expansion is analysed and discussed.

  11. High Current Ion Source Development for Heavy Ion Fusion

    SciTech Connect

    Westenskow, G A; Grote, D P; Kwan, J W

    2003-09-04

    We are developing high-current-density high-brightness sources for Heavy Ion Fusion applications. Heavy ion driven inertial fusion requires beams of high brightness in order to achieve high power density at the target for high target gain. At present, there are no existing ion source types that can readily meet all the driver HIF requirements, though sources exist which are adequate for present experiments and which with further development may achieve driver requirements. Our two major efforts have been on alumino-silicate sources and RF plasma sources. Experiments being performed on a 10-cm alumino-silicate source are described. To obtain a compact system for a HIF driver we are studying RF plasma sources where low current beamlets are combined to produce a high current beam. A 80-kV 20-{micro}s source has produced up to 5 mA of Ar{sup +} in a single beamlet. The extraction current density was 100 mA/cm{sup 2}. We present measurements of the extracted current density as a function of RF power and gas pressure, current density uniformity, emittance, and energy dispersion (due to charge exchange).

  12. Efficient electromigration testing with a single current source

    NASA Astrophysics Data System (ADS)

    Kim, Choong-Un; Michael, N. L.; Jiang, Qing-Tang; Augur, Rod

    2001-10-01

    This article introduces a simple and effective technique for conducting electromigration testing of a number of samples using a single current source. It is based on a configuration where all samples are serially connected to a single current source, allowing them to be subjected to identical current conditions. In this design, each sample has a current bypass circuit, consisting essentially of a computer controlled shunt relay and a Zener diode, to enable continuation of testing without any interruption in the test current when samples fail. With this technique, a large number of samples can be tested with the same current and excellent current stability, making it suitable for both reliability assessment and scientific investigation of electromigration mechanisms. Initial results show high correlation with industry standard testing systems.

  13. Vortex shaped current sources in a physical torso phantom.

    PubMed

    Liehr, Mario; Haueisen, Jens; Goernig, Matthias; Seidel, Paul; Nenonen, Jukka; Katila, Toivo

    2005-02-01

    Recent studies reported differential information in human magnetocardiogram and in electrocardiogram. Vortex currents have been discussed as a possible source of this divergence. With the help of physical phantom experiments, we quantified the influence of active vortex currents on the strength of electric and magnetic signals, and we tested the ability of standard source localization algorithms to reconstruct vortex currents. The active vortex currents were modeled by a set of twelve single current dipoles arranged in a circle and mounted inside a phantom that resembles a human torso. Magnetic and electric data were recorded simultaneously while the dipoles were switched on stepwise one after the other. The magnetic signal strength increased continuously for an increasing number of dipoles switched on. The electric signal strength increased up to a semicircle and decreased thereafter. Source reconstruction with unconstrained focal source models performed well for a single dipole only (less than 3-mm localization error). Minimum norm source reconstruction yielded reasonable results only for a few of the dipole configurations. In conclusion active vortex currents might explain, at least in part, the difference between magnetically and electrically acquired data, but improved source models are required for their reconstruction.

  14. Constant-Current Source For Measuring Low Resistances

    NASA Technical Reports Server (NTRS)

    Toomath, Robert L.

    1996-01-01

    Constant-current source constructed for measuring electrical resistances up to few ohms in power-supply equipment. By setting current at 1 A and measuring resulting voltage drop across item under test, one obtains voltage reading numerically equal to resistance in ohms.

  15. MEG-based imaging of focal neuronal current sources

    SciTech Connect

    Phillips, J.W.; Leahy, R.M.; Mosher, J.C.

    1996-07-01

    We describe a new approach to imaging neuronal current sources from measurements of the magnetoencephalogram (MEG) associated with sensory, motor, or cognitive brain activation. Previous approaches to this problem have concentrated on the use of weighted minimum norm inverse methods. While these methods ensure a unique solution, they do not introduce information specific to the MEG inverse problem, often producing overly smoothed solutions and exhibiting severe sensitivity to noise. We describe a Bayesian formulation of the inverse problem in which a Gibbs prior is constructed to reflect the sparse focal nature of neuronal current sources associated with evoked response data. The prior involves a binary process indicating active sources and a continuous Gaussian process designating associated amplitudes. An estimate of the primary current source distribution for a specific data set is formed by maximizing over the posterior probability with respect to the binary and continuous variables.

  16. Bridging faults in BiCMOS circuits

    NASA Technical Reports Server (NTRS)

    Menon, Sankaran M.; Malaiya, Yashwant K.; Jayasumana, Anura P.

    1993-01-01

    Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology for many high performance digital and mixed signal applications. Recent investigations revealed that bridging faults can be a major failure mode in IC's. Effects of bridging faults in BiCMOS circuits are presented. Bridging faults between logical units without feedback and logical units with feedback are considered. Several bridging faults can be detected by monitoring the power supply current (I(sub DDQ) monitoring). Effects of bridging faults and bridging resistance on output logic levels were examined along with their effects on noise immunity.

  17. Nanopore-CMOS Interfaces for DNA Sequencing.

    PubMed

    Magierowski, Sebastian; Huang, Yiyun; Wang, Chengjie; Ghafar-Zadeh, Ebrahim

    2016-08-06

    DNA sequencers based on nanopore sensors present an opportunity for a significant break from the template-based incumbents of the last forty years. Key advantages ushered by nanopore technology include a simplified chemistry and the ability to interface to CMOS technology. The latter opportunity offers substantial promise for improvement in sequencing speed, size and cost. This paper reviews existing and emerging means of interfacing nanopores to CMOS technology with an emphasis on massively-arrayed structures. It presents this in the context of incumbent DNA sequencing techniques, reviews and quantifies nanopore characteristics and models and presents CMOS circuit methods for the amplification of low-current nanopore signals in such interfaces.

  18. Switchable spin-current source controlled by magnetic domain walls.

    PubMed

    Savero Torres, W; Laczkowski, P; Nguyen, V D; Rojas Sanchez, J C; Vila, L; Marty, A; Jamet, M; Attané, J P

    2014-07-09

    Using nonlocal spin injection, spin-orbit coupling, or spincaloritronic effects, the manipulation of pure spin currents in nanostructures underlies the development of new spintronic devices. Here, we demonstrate the possibility to create switchable pure spin current sources, controlled by magnetic domain walls. When the domain wall is located at a given point of the magnetic circuit, a pure spin current is injected into a nonmagnetic wire. Using the reciprocal measurement configuration, we demonstrate that the proposed device can also be used as a pure spin current detector. Thanks to its simple geometry, this device can be easily implemented in spintronics applications; in particular, a single current source can be used both to induce the domain wall motion and to generate the spin signal.

  19. Performance evaluation of wideband bio-impedance spectroscopy using constant voltage source and constant current source

    NASA Astrophysics Data System (ADS)

    Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee

    2012-10-01

    Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in

  20. The MEVVA ion source for high current metal ion implantation

    NASA Astrophysics Data System (ADS)

    Brown, Ian; Washburn, Jack

    The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to 120 kV. A total ion beam current of over 1 A has been extracted from the present embodiment of the concept, and this is not an inherent limit. The ion charge state distribution varies with cathode material and are current, and beams like Li +, Co +.2+.3+ and U 3+.4+.5+.6+ for example, are typical; thus the implantation energy can be up to several hundred kV without additional acceleration. The ion source has potential applications for ion implantation and ion beam mixing for achievement of improved corrosion resistance or wear resistance in metals or surface modification of ceramic materials and semiconductors. Here we outline the source and its performance, and describe some very preliminary implantation work using this source.

  1. Large bandwidth op-amp based white noise current source

    NASA Astrophysics Data System (ADS)

    Giusi, Gino; Scandurra, Graziella; Ciofi, Carmine

    2014-02-01

    Electrical noise sources are basic building blocks in many measurement and instrumentation applications and in communication systems. In this paper, we propose a quite simple topology for the realization of a programmable, wide bandwidth, white noise current source that requires only two resistors and one operational amplifier. We validate the proposed approach by means of SPICE simulations and demonstrate, by means of proper measurements, the capability of generating a flat current noise spectrum in a frequency range up to four decades from a few Hz up to 100 kHz.

  2. Self-referenced single-electron quantized current source.

    PubMed

    Fricke, Lukas; Wulf, Michael; Kaestner, Bernd; Hohls, Frank; Mirovsky, Philipp; Mackrodt, Brigitte; Dolata, Ralf; Weimann, Thomas; Pierz, Klaus; Siegner, Uwe; Schumacher, Hans W

    2014-06-06

    The future redefinition of the international system of units in terms of natural constants requires a robust, high-precision quantum standard for the electrical base unit ampere. However, the reliability of any single-electron current source generating a nominally quantized output current I=ef by delivering single electrons with charge e at a frequency f is eventually limited by the stochastic nature of the underlying quantum mechanical tunneling process. We experimentally explore a path to overcome this fundamental limitation by serially connecting clocked single-electron emitters with multiple in situ single-electron detectors. Correlation analysis of the detector signatures during current generation reveals erroneous pumping events and enables us to determine the deviation of the output current from the nominal quantized value ef. This demonstrates the concept of a self-referenced single-electron source for electrical quantum metrology.

  3. Effective shielding to measure beam current from an ion source

    SciTech Connect

    Bayle, H.; Delferrière, O.; Gobin, R.; Harrault, F.; Marroncle, J.; Senée, F.; Simon, C.; Tuske, O.

    2014-02-15

    To avoid saturation, beam current transformers must be shielded from solenoid, quad, and RFQ high stray fields. Good understanding of field distribution, shielding materials, and techniques is required. Space availability imposes compact shields along the beam pipe. This paper describes compact effective concatenated magnetic shields for IFMIF-EVEDA LIPAc LEBT and MEBT and for FAIR Proton Linac injector. They protect the ACCT Current Transformers beyond 37 mT radial external fields. Measurements made at Saclay on the SILHI source are presented.

  4. Design of a 10-bit segmented current-steering digital-to-analog converter in CMOS 65 nm technology for the bias of new generation readout chips in high radiation environment

    NASA Astrophysics Data System (ADS)

    De Robertis, G.; Loddo, F.; Mattiazzo, S.; Pacher, L.; Pantano, D.; Tamma, C.

    2016-01-01

    A new pixel front end chip for HL-LHC experiments in CMOS 65nm technology is under development by the CERN RD53 collaboration together with the Chipix65 INFN project. This work describes the design of a 10-bit segmented current-steering Digital-to-Analog Converter (DAC) to provide a programmable bias current to the analog blocks of the circuit. The main requirements are monotonicity, good linearity, limited area consumption and radiation hardness up to 10 MGy. The DAC was prototyped and electrically tested, while irradiation tests will be performed in Autumn 2015.

  5. Brazilian Synchrotron Light Source: current results and future perspectives

    NASA Astrophysics Data System (ADS)

    Roque da Silva, Antonio Jose

    2013-03-01

    The application of synchrotron radiation in a great variety of fields in general, and condensed matter in particular, has increased steadily worldwide. This, to a large extent, is a result of the availability of the much brighter third-generation light sources, which opened up new experimental techniques. Brazil gave an important contribution to science in Latin America through the development of the necessary technology and the construction of the first synchrotron in the southern hemisphere, still the only one in Latin America. The Laboratório Nacional de Luz Síncrotron - LNLS, operates this installation as an open facility since 1997, having today more than 1300 users yearly. Despite all this success, the current Brazilian light source is a second-generation machine, with relatively low electron energy, high emittance and few straight sections for insertion devices. LNLS is currently engaged in the design and construction of a new, third-generation synchrotron light source. It is being planned to be a state of the art machine, providing tools for cutting edge research that are non existent today in Brazil. In this talk an overview of the status of the current Brazilian light source will be provided, illustrated with some experimental results from users, as well as the future perspectives of the new synchrotron source.

  6. Sources of field-aligned currents in the auroral plasma

    SciTech Connect

    Marshall, J.A.; Burch, J.L. ); Kan, J.R. ); Reiff, P.H. ); Slavin, J.A. )

    1991-01-01

    Data from the Dynamics Explorer 1 High Altitude Plasma Instrument (HAPI) and magnetometer are used to investigate the sources of field-aligned currents in the nightside auroral zone. It is found that the formula developed by S. Knight predicts the field-aligned current density fairly accurately in regions where a significant potential drop can be inferred from the HAPI data; there are, however, regions in which the proportionality between potential drop and field-aligned current does not hold. In particular, the authors note occurrences of strong upward field-aligned current associated not with inverted-V events but instead with suprathermal bursts. In addition, upward field-aligned currents are often observed to peak near the edges of inverted-V events, rather than in the center as would be predicted by Knight.

  7. Sources of field-aligned currents in the auroral plasma

    NASA Astrophysics Data System (ADS)

    Marshall, J. A.; Burch, J. L.; Kan, J. R.; Reiff, P. H.; Slavin, J. A.

    1991-01-01

    Data from the Dynamics Explorer 1 High Altitude Plasma Instrument (HAPI) and magnetometer are used to investigate the sources of field-aligned currents in the nightside auroral zone. It is found that the formula developed by S. Knight predicts the field-aligned current density fairly accurately in regions where a significant potential drop can be inferred from the HAPI data; there are, however, regions in which the proportionality between potential drop and field-aligned current does not hold. In particular, occurrences of strong upward field-aligned current associated not with inverted-V events but instead with suprathermal bursts are noted. In addition, upward field-aligned currents are often observed to peak near the edges of inverted-V events, rather than in the center as would be predicted by Knight.

  8. Behavior of faulty double BJT BiCMOS logic gates

    NASA Technical Reports Server (NTRS)

    Menon, Sankaran M.; Malaiya, Yashwant K.; Jayasumana, Anura P.

    1992-01-01

    Logic Behavior of a Double BJT BiCMOS device under transistor level shorts and opens is examined. In addition to delay faults, faults that cause the gate to exhibit sequential behavior were observed. Several faults can be detected only by monitoring the current. The faulty behavior of Bipolar (TTL) and CMOS logic families is compared with BiCMOS, to bring out the testability differences.

  9. Correct CMOS IC defect models for quality testing

    NASA Technical Reports Server (NTRS)

    Soden, Jerry M.; Hawkins, Charles F.

    1993-01-01

    Leading edge, high reliability, and low escape CMOS IC test practices have now virtually removed the stuck-at fault model and replaced it with more defect-orientated models. Quiescent power supply current testing (I(sub DDQ)) combined with strategic use of high speed test patterns is the recommended approach to zero defect and high reliability testing goals. This paper reviews the reasons for the change in CMOS IC test practices and outlines an improved CMOS IC test methodology.

  10. CAOS-CMOS camera.

    PubMed

    Riza, Nabeel A; La Torre, Juan Pablo; Amin, M Junaid

    2016-06-13

    Proposed and experimentally demonstrated is the CAOS-CMOS camera design that combines the coded access optical sensor (CAOS) imager platform with the CMOS multi-pixel optical sensor. The unique CAOS-CMOS camera engages the classic CMOS sensor light staring mode with the time-frequency-space agile pixel CAOS imager mode within one programmable optical unit to realize a high dynamic range imager for extreme light contrast conditions. The experimentally demonstrated CAOS-CMOS camera is built using a digital micromirror device, a silicon point-photo-detector with a variable gain amplifier, and a silicon CMOS sensor with a maximum rated 51.3 dB dynamic range. White light imaging of three different brightness simultaneously viewed targets, that is not possible by the CMOS sensor, is achieved by the CAOS-CMOS camera demonstrating an 82.06 dB dynamic range. Applications for the camera include industrial machine vision, welding, laser analysis, automotive, night vision, surveillance and multispectral military systems.

  11. Design, theoretical analysis, and experimental verification of a CMOS current integrator with 1.2 × 2.05 µm2 microelectrode array for high-sensitivity bacterial counting

    NASA Astrophysics Data System (ADS)

    Gamo, Kohei; Nakazato, Kazuo; Niitsu, Kiichi

    2017-01-01

    In this paper, we present the design and experimental verification of an amperometric CMOS-based sensor with a current integrator and a 1.2 × 2.05 µm2 bacterial-sized microelectrode array for high-sensitivity bacterial counting. For high-sensitivity bacterial counting with a sufficient signal-to-noise ratio (SNR), noise must be reduced because bacterial-sized microelectrodes can handle only a low current of the order of 100 pA. Thus, we implement a current integrator that is highly effective for noise reduction. Furthermore, for the first time, we use the current integrator in conjunction with the bacterial-sized microelectrode array. On the basis of the results of the proposed current integration, we successfully reduce noise and achieve a high SNR of 30.4 dB. To verify the effectiveness of the proposed CMOS-based sensor, we perform two-dimensional counting of microbeads, which are almost of the same size as bacteria. The measurement results demonstrate successful high-sensitivity two-dimensional (2D) counting of microbeads with a high SNR of 27 dB.

  12. MEG-based imaging of focal neuronal current sources

    SciTech Connect

    Phillips, J.W.; Leahy, R.M.; Mosher, J.C.

    1997-06-01

    The authors describe a new approach to imaging neural current sources from measurements of the magnetoencephalogram (MEG) associated with sensory, motor, or cognitive brain activation. Many previous approaches to this problem have concentrated on the use of weighted minimum norm (WMN) inverse methods. While these methods ensure a unique solution, they do not introduce information specific to the MEG inverse problem, often producing overly smoothed solutions and exhibiting severe sensitivity to noise. The authors describe a Bayesian formulation of the inverse problem in which a Gibbs prior is constructed to reflect the sparse focal nature of neural current sources associated with evoked response data. They demonstrate the method with simulated and experimental phantom data, comparing its performance with several WMN methods.

  13. ULTRA-LOW-ENERGY HIGH-CURRENT ION SOURCE

    SciTech Connect

    Anders, Andre; Yushkov, Georgy Yu.; Baldwin, David A.

    2009-11-20

    The technical objective of the project was to develop an ultra-low-energy, high-intensity ion source (ULEHIIS) for materials processing in high-technology fields including semiconductors, micro-magnetics and optics/opto-electronics. In its primary application, this ion source can be incorporated into the 4Wave thin-film deposition technique called biased target ion-beam deposition (BTIBD), which is a deposition technique based on sputtering (without magnetic field, i.e., not the typical magnetron sputtering). It is a technological challenge because the laws of space charge limited current (Child-Langmuir) set strict limits of how much current can be extracted from a reservoir of ions, such as a suitable discharge plasma. The solution to the problem was an innovative dual-discharge system without the use of extraction grids.

  14. High-resolution three-dimensional imaging of a depleted CMOS sensor using an edge Transient Current Technique based on the Two Photon Absorption process (TPA-eTCT)

    NASA Astrophysics Data System (ADS)

    García, Marcos Fernández; Sánchez, Javier González; Echeverría, Richard Jaramillo; Moll, Michael; Santos, Raúl Montero; Moya, David; Pinto, Rogelio Palomo; Vila, Iván

    2017-02-01

    For the first time, the deep n-well (DNW) depletion space of a High Voltage CMOS sensor has been characterized using a Transient Current Technique based on the simultaneous absorption of two photons. This novel approach has allowed to resolve the DNW implant boundaries and therefore to accurately determine the real depleted volume and the effective doping concentration of the substrate. The unprecedented spatial resolution of this new method comes from the fact that measurable free carrier generation in two photon mode only occurs in a micrometric scale voxel around the focus of the beam. Real three-dimensional spatial resolution is achieved by scanning the beam focus within the sample.

  15. Development of a Depleted Monolithic CMOS Sensor in a 150 nm CMOS Technology for the ATLAS Inner Tracker Upgrade

    NASA Astrophysics Data System (ADS)

    Wang, T.; Rymaszewski, P.; Barbero, M.; Degerli, Y.; Godiot, S.; Guilloux, F.; Hemperek, T.; Hirono, T.; Krüger, H.; Liu, J.; Orsini, F.; Pangaud, P.; Rozanov, A.; Wermes, N.

    2017-01-01

    The recent R&D focus on CMOS sensors with charge collection in a depleted zone has opened new perspectives for CMOS sensors as fast and radiation hard pixel devices. These sensors, labelled as depleted CMOS sensors (DMAPS), have already shown promising performance as feasible candidates for the ATLAS Inner Tracker (ITk) upgrade, possibly replacing the current passive sensors. A further step to exploit the potential of DMAPS is to investigate the suitability of equipping the outer layers of the ATLAS ITk upgrade with fully monolithic CMOS sensors. This paper presents the development of a depleted monolithic CMOS pixel sensor designed in the LFoundry 150 nm CMOS technology, with the focus on design details and simulation results.

  16. OFF-SITE SOURCE RECOVERY PROJECT HISTORY AND CURRENT STATUSS

    SciTech Connect

    M. W. PERASON; C. O. GRIGSBY; ET AL

    2000-09-01

    Beginning in the 1950's the federal government, through the Atomic Energy Commission, began providing limited quantities of special nuclear material to industry and research institutions to stimulate advances in nuclear science and technology. By the early 1960s the identified beneficial uses of radioactive material had added Am-241, Cs- 137, CO-60, and Sr-90 to the list of common isotopes which were distributed in significant numbers as high-energy sealed sources for industry, medicine and research. By the mid 1980s many of these sealed radioactive sources were thirty years old and the changing priorities of research and industry had rendered many of them excess. Unfortunately, many of these sources exceeded activity limits established for Low-Level Waste (LLW) disposal and the owners were left with no viable options to rid themselves of unwanted material. In 1985, Congress attempted to address this concern by assigning responsibility for disposal of radioactive material which exceeded the Class-C LLW limits to the US Department of Energy (DOE) in the Low-Level Waste Policy Amendments Act of 1985 (PL 99-240). As with other attempts for disposal facility development however, the years passed and the facilities were not forthcoming. This paper briefly describes the history of government efforts to effect retrieval of these sources and provides projections on availability of retrieval services by Los Alamos National Laboratory (LANL). A summary of eligible materials, points of contact at LANL, and recommended actions by current source owners are included.

  17. Polarity detection in ultrasound current source density imaging.

    PubMed

    Zhaohui Wang; Wei-Da Hao; Leung, Chung S; Sung-Won Park

    2016-08-01

    Modulating the electric dipole field with ultrasound pulse, ultrasound current source density imaging (UCSDI) can detect current direction and form spatial 3D imaging of dipole changing in one period of treatment. As ultrasound pulse passes through the conductive media, it convolves/correlates with the inner product of the electric field of a dipole and lead field of a pair of detectors, making the shifting frequency of polarity lower than the center frequency of the ultrasound pulse. After acoustoelectric (AE) signal is shifted to base band, the AE voltage is positive at anode and negative at cathode. In the simulation, the lead fields of detectors and electric field of dipole were calculated by the finite element (FE) method; the convolution and correlation in the computation of AE signal were accelerated using 3-D fast Fourier transforms. The current direction and amplitude are encoded in the phase and amplitude of the AE signal. Based on the analysis of polarity algorithms on the simulated and in-vitro ultrasound current source density images, it is concluded that the cross-correlation method is significantly better than the autocorrelation method to extract the frequency shift for high pulse bandwidth.

  18. Physics of Intense Electron Current Sources for Helicity Injection

    NASA Astrophysics Data System (ADS)

    Hinson, E. T.; Barr, J. L.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Lewicki, B. T.; Perry, J. M.; Redd, A. J.; Winz, G. R.

    2014-10-01

    DC helicity injection (HI) for non-solenoidal ST startup requires sources of current at the tokamak edge. Since the rate of HI scales with injection voltage, understanding of the physics setting injector impedance is necessary for a predictive model of the HI rate and subsequent growth of Ip. In Pegasus, arc plasma sources are used for current injection. They operate immersed in tokamak edge plasma, and are biased at ~1-2 kV with respect to the vessel to draw current densities J ~ 1 kA/cm2 from an arc plasma cathode. Prior to tokamak formation, impedance data manifests two regimes, one at low current (< 1 kA) with I ~V 3 / 2 , and a higher current mode where I ~V 1 / 2 holds. The impedance in the I ~V 3 / 2 regime is consistent with an electrostatic double layer. Current in the I ~V 1 / 2 regime is linear in arc gas fueling rate, suggesting a space-charge limit set by nedge. In the presence of tokamak plasmas, voltage oscillations of the order 100s of volts are measured during MHD relaxation activity. These fluctuations occur at the characteristic frequencies of the n = 1 and n = 0 MHD activity observed on magnetic probes, and are suggestive of dynamic activity found in LHI simulations in NIMROD. Advanced injector design techniques have allowed higher voltage operation. These include staged shielding to prevent external arcing, and shaped cathodes, which minimize the onset and material damage due to cathode spot formation. Work supported by US DOE Grant DE-FG02-96ER54375.

  19. Fully depleted and backside biased monolithic CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Stefanov, Konstantin D.; Clarke, Andrew S.; Holland, Andrew D.

    2016-07-01

    We are presenting a novel concept for a fully depleted, monolithic, pinned photodiode CMOS image sensor using reverse substrate bias. The principle of operation allows the manufacture of backside illuminated CMOS sensors with active thickness in excess of 100 μm. This helps increase the QE at near-IR and soft X-ray wavelengths, while preserving the excellent characteristics associated with the pinned photodiode sensitive elements. Such sensors are relevant to a wide range of applications, including scientific imaging, astronomy, Earth observation and surveillance. A prototype device with 10 μm and 5.4 μm pixels using this concept has been designed and is being manufactured on a 0.18 μm CMOS image sensor process. Only one additional implantation step has been introduced to the normal manufacturing flow to make this device. The paper discusses the design of the sensor and the challenges that had to be overcome to realise it in practice, and in particular the method of achieving full depletion without parasitic substrate currents. It is expected that this new technology can be competitive with modern backside illuminated thick CCDs for use at visible to near-IR telescopes and synchrotron light sources.

  20. Improved current control makes inverters the power sources of choice

    SciTech Connect

    Yamamoto, H.; Harada, S.; Ueyama, T.

    1997-02-01

    It is now generally understood that by increasing the operating or switching frequency of a power source the size of the main transformer and main reactor can be shrunk. Thus, a 300-A DC welding power source weighing well under 100 lb can be produced. This makes the inverter power source an ideal choice for applications requiring equipment maneuverability. It is also generally understood that due to higher switching frequencies, a smoother output is obtained from inverter power sources. In the late 1980s, the company developed a new double-inverter power source by which inverted DC weld output is inverted back to AC weld output. This product was the first of its kind in the world. Again, the small compact size of this product was of great interest. Utilizing current waveform control, it was realized that fast response switching from electrode negative to electrode positive could be accurately controlled, offering benefits such as AC GTA welding with high-frequency start only, even at a low welding current. The primary benefit is the ability to limit the electrode positive half cycle to less than 5%. The electrode positive half cycle is responsible for tungsten erosion, which also creates the balling effect of a tungsten electrode. By limiting the electrode positive portion of the AC cycle to a very low level, a rather sharp point can be maintained on the tungsten, which creates a very concentrated, focused arc column. This ability provides excellent joint penetration in fillet welding of aluminum alloys, especially on thick plate. It also reduces the heat-affected zone in AC GTA welding of aluminum.

  1. Heliospheric current sheet inclinations predicted from source surface maps

    NASA Technical Reports Server (NTRS)

    Shodhan, S.; Crooker, N. U.; Hughes, W. J.; Siscoe, G. L.

    1994-01-01

    The inclinations of the neutral line at the ecliptic plane derived from source surface model maps of coronal fields are measured for the interval from June 1976 to March 1992. The mean and median values of 53 deg and 57 deg are close to the average inclinations determined earlier from minimum variance analyses of solar wind measurements at sector boundaries, but the mode falls in the 80 deg - 90 deg bin. This result, which is based on the model assumptions implicit in deriving the source surface maps, predicts that the heliospheric current sheet typically intersects the ecliptic plane nearly at right angles, even without steepening by stream interaction regions. High inclinations dominate the solar cycle for about 7 years around solar maximum. Dips to lower inclination occur near solar minimum, but high variance admits a wide range of inclinations throughout the cycle. Compared to the smooth solar cycle variation of the maximum latitudinal excursion of the neutral line, often treated as the tilt angle of a flat heliospheric current sheet, the noisy variation of the inclinations reflects the degree to which the neutral line deviates from a sine wave, implying warps and corrugations in the current sheet. About a third of the time the neutral line so deviates that it doubles back in longitude.

  2. Fault Current Limiter by Series Connected Voltage Source Inverter

    NASA Astrophysics Data System (ADS)

    Hojo, Masahide; Kuroe, Norihito; Ohnishi, Tokuo

    In recent years, various types of fault current limiter (FCL) have been developed, because installation of the FCL will bring a lot of benefits to power system operation. Power system controllers based on a concept of Flexible AC Transmission Systems (FACTS) can also be applicable as the FCL with growing power ratings of them. Such FCLs are expected to contribute power system stabilization or power quality enhancement in addition to fault current limitation. Authors have developed a new type of FCL, which consists of a series reactor and a self-commutated voltage source inverter connected in series with a power distribution line by a coupling transformer. In case of a system fault, the FCL will insert a sufficiently large inductance in series with the distribution line by both the series reactor and the inverter, then it will reduce the fault current. On the other hand, the inverter compensates a voltage drop across the series reactor in a standby mode. As a result, the FCL behaves like a negligible impedance in the standby mode. One of the distinctive features of the FCL is a simple configuration because its control strategy does not require an active power source. In addition, inverter voltage rating of the proposed FCL can be reduced by installing the series reactor as compared with other converter-based FCLs. The aim of this paper is to evaluate the operating characteristics of the FCL with both simulation and experimental studies.

  3. Heliospheric current sheet inclinations predicted from source surface maps

    NASA Technical Reports Server (NTRS)

    Shodhan, S.; Crooker, N. U.; Hughes, W. J.; Siscoe, G. L.

    1994-01-01

    The inclinations of the neutral line at the ecliptic plane derived from source surface model maps of coronal fields are measured for the interval from June 1976 to March 1992. The mean and median values of 53 deg and 57 deg are close to the average inclinations determined earlier from minimum variance analyses of solar wind measurements at sector boundaries, but the mode falls in the 80 deg - 90 deg bin. This result, which is based on the model assumptions implicit in deriving the source surface maps, predicts that the heliospheric current sheet typically intersects the ecliptic plane nearly at right angles, even without steepening by stream interaction regions. High inclinations dominate the solar cycle for about 7 years around solar maximum. Dips to lower inclination occur near solar minimum, but high variance admits a wide range of inclinations throughout the cycle. Compared to the smooth solar cycle variation of the maximum latitudinal excursion of the neutral line, often treated as the tilt angle of a flat heliospheric current sheet, the noisy variation of the inclinations reflects the degree to which the neutral line deviates from a sine wave, implying warps and corrugations in the current sheet. About a third of the time the neutral line so deviates that it doubles back in longitude.

  4. Electric machine and current source inverter drive system

    DOEpatents

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  5. CMOS sensor for face tracking and recognition

    NASA Astrophysics Data System (ADS)

    Ginhac, Dominique; Prasetyo, Eri; Paindavoine, Michel

    2005-03-01

    This paper describes the main principles of a vision sensor dedicated to the detecting and tracking faces in video sequences. For this purpose, a current mode CMOS active sensor has been designed using an array of pixels that are amplified by using current mirrors of column amplifier. This circuit is simulated using Mentor Graphics software with parameters of a 0.6 μm CMOS process. The circuit design is added with a sequential control unit which purpose is to realise capture of subwindows at any location and any size in the whole image.

  6. High current liquid metal ion source using porous tungsten multiemitters.

    PubMed

    Tajmar, M; Vasiljevich, I; Grienauer, W

    2010-12-01

    We recently developed an indium Liquid-Metal-Ion-Source that can emit currents from sub-μA up to several mA. It is based on a porous tungsten crown structure with 28 individual emitters, which is manufactured using Micro-Powder Injection Molding (μPIM) and electrochemical etching. The emitter combines the advantages of internal capillary feeding with excellent emission properties due to micron-size tips. Significant progress was made on the homogeneity of the emission over its current-voltage characteristic as well as on investigating its long-term stability. This LMIS seems very suitable for space propulsion as well as for micro/nano manufacturing applications with greatly increased milling/drilling speeds. This paper summarizes the latest developments on our porous multiemitters with respect to manufacturing, emission properties and long-term testing. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. High current DC negative ion source for cyclotron

    NASA Astrophysics Data System (ADS)

    Etoh, H.; Onai, M.; Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Hiasa, T.; Yajima, S.; Shibata, T.; Hatayama, A.; Okumura, Y.

    2016-02-01

    A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H- beam of 10 mA and D- beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H- beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H- current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H- production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H- current dependence on the arc power.

  8. High current DC negative ion source for cyclotron

    SciTech Connect

    Etoh, H. Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Hiasa, T.; Yajima, S.; Onai, M.; Hatayama, A.; Shibata, T.; Okumura, Y.

    2016-02-15

    A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H{sup −} beam of 10 mA and D{sup −} beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H{sup −} beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H{sup −} current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H{sup −} production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H{sup −} current dependence on the arc power.

  9. A high-current pulsed cathodic vacuum arc plasma source

    NASA Astrophysics Data System (ADS)

    Oates, T. W. H.; Pigott, J.; Mckenzie, D. R.; Bilek, M. M. M.

    2003-11-01

    Cathodic vacuum arcs (CVAs) are well established as a method for producing metal plasmas for thin film deposition and as a source of metal ions. Fundamental differences exist between direct current (dc) and pulsed CVAs. We present here results of our investigations into the design and construction of a high-current center-triggered pulsed CVA. Power supply design based on electrolytic capacitors is discussed and optimized based on obtaining the most effective utilization of the cathode material. Anode configuration is also discussed with respect to the optimization of the electron collection capability. Type I and II cathode spots are observed and discussed with respect to cathode surface contamination. An unfiltered deposition rate of 1.7 nm per pulse, at a distance of 100 mm from the source, has been demonstrated. Instantaneous plasma densities in excess of 1×1019 m-3 are observed after magnetic filtering. Time averaged densities an order of magnitude greater than common dc arc densities have been demonstrated, limited by pulse repetition rate and filter efficiency.

  10. CMOS VCSEL driver circuit for 25+Gbps/channel short-reach parallel optical links

    NASA Astrophysics Data System (ADS)

    Shibata, Masumi

    This thesis proposes a new CMOS driver for Vertical Cavity Surface Emitting LASER (VCSEL) diode arrays. A VCSEL is a promising light source for optical communication. However, its threshold voltage (1.5V for a 850-nm VCSEL) exceeds the rated supply voltage of nanoscale CMOS technologies. This makes difficult designing a driver sourcing a modulated current to a VCSELs anode directly, an arrangement suitable for low-cost parallel optical links. To overcome this problem, a combination of analog circuit techniques is proposed including a novel pad shield driving technique. A prototype fabricated in a 65-nm CMOS technology achieved 26-Gb/s bit-rate and 1.80-pJ/b power efficiency with an optical modulation amplitude (OMA) of +1.8dBm and 3.1ps-rms jitter when driving a 850-nm 14Gb/s commercial VCSEL. This is the highest-speed anode-driving CMOS VCSEL driver reported to date. Also it has the best power efficiency and the smallest area (0:024 mm2) amongst anode-driving drivers in any process technology.

  11. Fundamental study on identification of CMOS cameras

    NASA Astrophysics Data System (ADS)

    Kurosawa, Kenji; Saitoh, Naoki

    2003-08-01

    In this study, we discussed individual camera identification of CMOS cameras, because CMOS (complementary-metal-oxide-semiconductor) imaging detectors have begun to make their move into the CCD (charge-coupled-device) fields for recent years. It can be identified whether or not the given images have been taken with the given CMOS camera by detecting the imager's intrinsic unique fixed pattern noise (FPN) just like the individual CCD camera identification method proposed by the authors. Both dark and bright pictures taken with the CMOS cameras can be identified by the method, because not only dark current in the photo detectors but also MOS-FET amplifiers incorporated in each pixel may produce pixel-to-pixel nonuniformity in sensitivity. Each pixel in CMOS detectors has the amplifier, which degrades image quality of bright images due to the nonuniformity of the amplifier gain. Two CMOS cameras were evaluated in our experiments. They were WebCamGoPlus (Creative), and EOS D30 (Canon). WebCamGoPlus is a low-priced web camera, whereas EOS D30 is for professional use. Image of a white plate were recorded with the cameras under the plate's luminance condition of 0cd/m2 and 150cd/m2. The recorded images were multiply integrated to reduce the random noise component. From the images of both cameras, characteristic dots patterns were observed. Some bright dots were observed in the dark images, whereas some dark dots were in the bright images. The results show that the camera identification method is also effective for CMOS cameras.

  12. Experiments with synchronized sCMOS cameras

    NASA Astrophysics Data System (ADS)

    Steele, Iain A.; Jermak, Helen; Copperwheat, Chris M.; Smith, Robert J.; Poshyachinda, Saran; Soonthorntham, Boonrucksar

    2016-07-01

    Scientific-CMOS (sCMOS) cameras can combine low noise with high readout speeds and do not suffer the charge multiplication noise that effectively reduces the quantum efficiency of electron multiplying CCDs by a factor 2. As such they have strong potential in fast photometry and polarimetry instrumentation. In this paper we describe the results of laboratory experiments using a pair of commercial off the shelf sCMOS cameras based around a 4 transistor per pixel architecture. In particular using a both stable and a pulsed light sources we evaluate the timing precision that may be obtained when the cameras readouts are synchronized either in software or electronically. We find that software synchronization can introduce an error of 200-msec. With electronic synchronization any error is below the limit ( 50-msec) of our simple measurement technique.

  13. Design of single-gate n-channel and p-channel MOSFETs with enhanced current-drive due to simultaneous switching of front and back channels in SOI CMOS technology

    NASA Astrophysics Data System (ADS)

    Bindu, B.; Lakshmi, N.; Bhat, K. N.; DasGupta, Amitava

    2006-07-01

    In this paper, we show that when single gate SOI MOSFETs are biased at a particular ideal back gate voltage, the front and back channels can be turned ON and OFF simultaneously using the front gate voltage, thereby enhancing the current drive of the device. It is shown by analytical models as well as 2-D numerical simulation that both maximum transconductance and minimum subthreshold slope are obtained for this ideal back gate bias. Subsequently, n-channel and p-channel MOSFETs are designed for a conventional SOI CMOS process, where both the front and back channels of these devices turn ON and OFF simultaneously resulting in enhanced current drive and superior performance. The design has been carried out with the help of analytical formulation and verified using the 2-D Device Simulator MEDICI.

  14. Failures Of CMOS Devices At Low Radiation-Dose Rates

    NASA Technical Reports Server (NTRS)

    Goben, Charles A.; Price, William E.

    1990-01-01

    Method for obtaining approximate failure-versus-dose-rate curves derived from experiments on failures of SGS 4007 complementary metal oxide/semiconductor (CMOS) integrated circuits irradiated by Co60 and Cs137 radioactive sources.

  15. New progress of high current gasdynamic ion source (invited).

    PubMed

    Skalyga, V; Izotov, I; Golubev, S; Sidorov, A; Razin, S; Vodopyanov, A; Tarvainen, O; Koivisto, H; Kalvas, T

    2016-02-01

    The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)-the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller's ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 10(13) cm(-3)) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10(-4)-10(-3) mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ⋅ mm ⋅ mrad have been demonstrated in recent experiments.

  16. New progress of high current gasdynamic ion source (invited)

    SciTech Connect

    Skalyga, V. Sidorov, A.; Vodopyanov, A.; Izotov, I.; Golubev, S.; Razin, S.; Tarvainen, O.; Koivisto, H.; Kalvas, T.

    2016-02-15

    The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)—the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller’s ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 10{sup 13} cm{sup −3}) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10{sup −4}–10{sup −3} mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ⋅ mm ⋅ mrad have been demonstrated in recent experiments.

  17. New progress of high current gasdynamic ion source (invited)

    NASA Astrophysics Data System (ADS)

    Skalyga, V.; Izotov, I.; Golubev, S.; Sidorov, A.; Razin, S.; Vodopyanov, A.; Tarvainen, O.; Koivisto, H.; Kalvas, T.

    2016-02-01

    The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)—the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller's ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 1013 cm-3) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10-4-10-3 mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ṡ mm ṡ mrad have been demonstrated in recent experiments.

  18. Plasma Generation in High-Current Ion Sources

    NASA Astrophysics Data System (ADS)

    Filuk, A. B.; Cuneo, M. E.; Mehlhorn, T. A.; Pointon, T. D.; Vesey, R. A.; Welch, D.

    1996-10-01

    We are using kA/cm^2 ion sources to generate intense pulsed ion beams for driving Inertial Confinement Fusion targets. These sources are the anode of an ion diode that uses several-Tesla magnetic fields to restrict electron flow across the diode while permitting ion acceleration. Our 2 cm diode anode-cathode gaps have 10 MV applied in order to accelerate Li ions from 100-1000 cm^2 anode areas. During the 50 ns beam pulse, we observe a transition in beam content from Li ions to H,C,O impurity ions. As well, a significant fraction of the total diode current is in electrons leaking across the magnetic insulation to the anode. The several-GW/cm^2 leakage flux of MeV electrons deposits large amounts of energy into the anode surface, releasing physi- and chemi-sorbed impurities in the modest 10-5-10-6 Torr diode vacuum. These desorbed impurity neutrals can expand and rapidly ionize within about 200 μm of the anode during the beam pulse. We are modeling this process in a multi-dimensional hybrid fluid/PIC code and making spectroscopic measurements to quantify these mechanisms.

  19. Optical addressing technique for a CMOS RAM

    NASA Technical Reports Server (NTRS)

    Wu, W. H.; Bergman, L. A.; Allen, R. A.; Johnston, A. R.

    1988-01-01

    Progress on optically addressing a CMOS RAM for a feasibility demonstration of free space optical interconnection is reported in this paper. The optical RAM chip has been fabricated and functional testing is in progress. Initial results seem promising. New design and SPICE simulation of optical gate cell (OGC) circuits have been carried out to correct the slow fall time of the 'weak pull down' OGC, which has been characterized experimentally. Methods of reducing the response times of the photodiodes and the associated circuits are discussed. Even with the current photodiode, it appears that an OGC can be designed with a performance that is compatible with a CMOS circuit such as the RAM.

  20. CMOS detectors at Rome "Tor Vergata" University

    NASA Astrophysics Data System (ADS)

    Berrilli, F.; Cantarano, S.; Egidi, A.; Giordano, S.

    The new class of CMOS panoramic detectors represents an innovative tool for the experimental astronomy of the forthcoming years. While current charge-coupled device (CCD) technology can produce nearly ideal detectors for astronomical use, the scientific quality CMOS detectors made today have characteristics similar to those of CCD devices but a simpler electronics and a reduced cost. Moreover, the high frame rate capability and the amplification of each pixel - active pixel - in a CMOS detector, allows the implementation of a specific data management. So, it is possible to design cameras with very high dynamic range suitable for the imaging of solar active regions. In fact, in such regions, the onset of a flare can produce problems of saturation in a CCD-based camera. In this work we present the preliminary result obtained with the Tor Vergata C-Cam APS camera used at the University Solar Station.

  1. Nanopore-CMOS Interfaces for DNA Sequencing

    PubMed Central

    Magierowski, Sebastian; Huang, Yiyun; Wang, Chengjie; Ghafar-Zadeh, Ebrahim

    2016-01-01

    DNA sequencers based on nanopore sensors present an opportunity for a significant break from the template-based incumbents of the last forty years. Key advantages ushered by nanopore technology include a simplified chemistry and the ability to interface to CMOS technology. The latter opportunity offers substantial promise for improvement in sequencing speed, size and cost. This paper reviews existing and emerging means of interfacing nanopores to CMOS technology with an emphasis on massively-arrayed structures. It presents this in the context of incumbent DNA sequencing techniques, reviews and quantifies nanopore characteristics and models and presents CMOS circuit methods for the amplification of low-current nanopore signals in such interfaces. PMID:27509529

  2. Alternative current source based Schottky contact with additional electric field

    NASA Astrophysics Data System (ADS)

    Mamedov, R. K.; Aslanova, A. R.

    2017-07-01

    Additional electric field (AEF) in the Schottky contacts (SC) that covered the peripheral contact region wide and the complete contact region narrow (as TMBS diode) SC. Under the influence of AEF is a redistribution of free electrons produced at certain temperatures of the semiconductor, and is formed the space charge region (SCR). As a result of the superposition of the electric fields SCR and AEF occurs the resulting electric field (REF). The REF is distributed along a straight line perpendicular to the contact surface, so that its intensity (and potential) has a minimum value on the metal surface and the maximum value at a great distance from the metal surface deep into the SCR. Under the influence of AEF as a sided force the metal becomes negative pole and semiconductor - positive pole, therefore, SC with AEF becomes an alternative current source (ACS). The Ni-nSi SC with different diameters (20-1000 μm) under the influence of the AEF as sided force have become ACS with electromotive force in the order of 0.1-1.0 mV, which are generated the electric current in the range of 10-9-10-7 A, flowing through the external resistance 1000 Ohm.

  3. A CMOS Front-End With Integrated Magnetoresistive Sensors for Biomolecular Recognition Detection Applications.

    PubMed

    Costa, Tiago; Cardoso, Filipe A; Germano, Jose; Freitas, Paulo P; Piedade, Moises S

    2017-10-01

    The development of giant magnetoresistive (GMR) sensors has demonstrated significant advantages in nanomedicine, particularly for ultrasensitive point-of-care diagnostics. To this end, the detection system is required to be compact, portable, and low power consuming at the same time that a maximum signal to noise ratio is maintained. This paper reports a CMOS front-end with integrated magnetoresistive sensors for biomolecular recognition detection applications. Based on the characterization of the GMR sensor's signal and noise, CMOS building blocks (i.e., current source, multiplexers, and preamplifier) were designed targeting a negligible noise when compared with the GMR sensor's noise and a low power consumption. The CMOS front-end was fabricated using AMS [Formula: see text] technology and the magnetoresistive sensors were post-fabricated on top of the CMOS chip with high yield ( [Formula: see text]). Due to its low circuit noise (16 [Formula: see text]) and overall equivalent magnetic noise ([Formula: see text]), the full system was able to detect 250 nm magnetic nanoparticles with a circuit imposed signal-to-noise ratio degradation of only -1.4 dB. Furthermore, the low power consumption (6.5 mW) and small dimensions ([Formula: see text] ) of the presented solution guarantees the portability of the detection system allowing its usage at the point-of-care.

  4. A review on high-resolution CMOS delay lines: towards sub-picosecond jitter performance.

    PubMed

    Abdulrazzaq, Bilal I; Abdul Halin, Izhal; Kawahito, Shoji; Sidek, Roslina M; Shafie, Suhaidi; Yunus, Nurul Amziah Md

    2016-01-01

    A review on CMOS delay lines with a focus on the most frequently used techniques for high-resolution delay step is presented. The primary types, specifications, delay circuits, and operating principles are presented. The delay circuits reported in this paper are used for delaying digital inputs and clock signals. The most common analog and digitally-controlled delay elements topologies are presented, focusing on the main delay-tuning strategies. IC variables, namely, process, supply voltage, temperature, and noise sources that affect delay resolution through timing jitter are discussed. The design specifications of these delay elements are also discussed and compared for the common delay line circuits. As a result, the main findings of this paper are highlighting and discussing the followings: the most efficient high-resolution delay line techniques, the trade-off challenge found between CMOS delay lines designed using either analog or digitally-controlled delay elements, the trade-off challenge between delay resolution and delay range and the proposed solutions for this challenge, and how CMOS technology scaling can affect the performance of CMOS delay lines. Moreover, the current trends and efforts used in order to generate output delayed signal with low jitter in the sub-picosecond range are presented.

  5. A high current, short pulse electron source for wakefield accelerators

    SciTech Connect

    Ho, Ching-Hung

    1992-12-31

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  6. A high current, short pulse electron source for wakefield accelerators

    SciTech Connect

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  7. Implantable CMOS Biomedical Devices

    PubMed Central

    Ohta, Jun; Tokuda, Takashi; Sasagawa, Kiyotaka; Noda, Toshihiko

    2009-01-01

    The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented. PMID:22291554

  8. Small-area and compact CMOS emulator circuit for CMOS/nanoscale memristor co-design

    PubMed Central

    2013-01-01

    In this paper, a CMOS emulator circuit that can reproduce nanoscale memristive behavior is proposed. The proposed emulator circuit can mimic the pinched hysteresis loops of nanoscale memristor memory's current-voltage relationship without using any resistor array, complicated circuit blocks, etc. that may occupy very large layout area. Instead of using a resistor array, other complicated circuit blocks, etc., the proposed emulator circuit can describe the nanoscale memristor's current-voltage relationship using a simple voltage-controlled resistor, where its resistance can be programmed by the stored voltage at the state variable capacitor. Comparing the layout area between the previous emulator circuit and the proposed one, the layout area of the proposed emulator circuit is estimated to be 32 times smaller than the previous emulator circuit. The proposed CMOS emulator circuit of nanoscale memristor memory will be very useful in developing hybrid circuits of CMOS/nanoscale memristor memory. PMID:24180626

  9. Small-area and compact CMOS emulator circuit for CMOS/nanoscale memristor co-design.

    PubMed

    Shin, Sanghak; Choi, Jun-Myung; Cho, Seongik; Min, Kyeong-Sik

    2013-11-01

    In this paper, a CMOS emulator circuit that can reproduce nanoscale memristive behavior is proposed. The proposed emulator circuit can mimic the pinched hysteresis loops of nanoscale memristor memory's current-voltage relationship without using any resistor array, complicated circuit blocks, etc. that may occupy very large layout area. Instead of using a resistor array, other complicated circuit blocks, etc., the proposed emulator circuit can describe the nanoscale memristor's current-voltage relationship using a simple voltage-controlled resistor, where its resistance can be programmed by the stored voltage at the state variable capacitor. Comparing the layout area between the previous emulator circuit and the proposed one, the layout area of the proposed emulator circuit is estimated to be 32 times smaller than the previous emulator circuit. The proposed CMOS emulator circuit of nanoscale memristor memory will be very useful in developing hybrid circuits of CMOS/nanoscale memristor memory.

  10. Performance of buried channel n-type MOSFETs in 0.18-μm CMOS image sensor process

    NASA Astrophysics Data System (ADS)

    Stefanov, Konstantin D.; Zhang, Zhige; Damerell, Chris; Burt, David; Kar-Roy, Arjun

    2013-09-01

    Buried channel (BC) MOSFETs are known to have better noise performance than surface channel (SC) MOSFETs when used as source followers in modern Charge Coupled Devices (CCD). CMOS image sensors find increasing range of applications and compete with CCDs in high performance imaging, however BC transistors are rarely used in CMOS. As a part of the development of charge storage using BC CCDs in CMOS, we designed and manufactured deep depletion BC n-type MOSFETs in 0.18 μm CMOS image sensor process. The transistors are designed in a way similar to the source followers in a typical BC CCD. In this paper we report the results from their characterization and compare with enhancement mode and "zero-threshold" SC devices. In addition to the detailed current-voltage and noise measurements, semiconductor device simulation results are presented to illustrate and understand the different conditions affecting the channel conduction and the noise performance of the BC transistors at low operating voltages. We show that the biasing of the BC transistors has to be carefully adjusted for optimal operation, and that their noise performance at the right operating conditions can be superior to SC devices, despite their lower gain as in-pixel source followers.

  11. The direct-current response of electrically conducting fractures excited by a grounded current source

    SciTech Connect

    Weiss, Chester J.; Aldridge, David F.; Knox, Hunter A.; Schramm, Kimberly A.; Bartel, Lewis C.

    2016-05-01

    Hydraulic fracture stimulation of low permeability reservoir rocks is an established and cross–cutting technology for enhancing hydrocarbon production in sedimentary formations and increasing heat exchange in crystalline geothermal systems. Whereas the primary measure of success is the ability to keep the newly generated fractures sufficiently open, long–term reservoir management requires a knowledge of the spatial extent, morphology, and distribution of the fractures — knowledge primarily informed by microseismic and ground deformation monitoring. To minimize the uncertainty associated with interpreting such data, we investigate through numerical simulation the usefulness of direct-current (DC) resistivity data for characterizing subsurface fractures with elevated electrical conductivity by considering a geophysical experiment consisting of a grounded current source deployed in a steel cased borehole. In doing so, the casing efficiently energizes the fractures with steady current. Finite element simulations of this experiment for a horizontal well intersecting a small set of vertical fractures indicate that the fractures manifest electrically in (at least) two ways: (1) a local perturbation in electric potential proximal to the fracture set, with limited farfield expression and (2) an overall reduction in the electric potential along the borehole casing due to enhanced current flow through the fractures into the surrounding formation. The change in casing potential results in a measurable effect that can be observed far from fractures themselves. Under these conditions, our results suggest that farfield, timelapse measurements of DC potentials can be interpreted by simple, linear inversion for a Coulomb charge distribution along the borehole path, including a local charge perturbation due to the fractures. As a result, this approach offers an inexpensive method for detecting and monitoring the time-evolution of electrically conducting fractures while

  12. The direct-current response of electrically conducting fractures excited by a grounded current source

    SciTech Connect

    Weiss, Chester J.; Aldridge, David F.; Knox, Hunter A.; Schramm, Kimberly A.; Bartel, Lewis C.

    2016-05-01

    Hydraulic fracture stimulation of low permeability reservoir rocks is an established and cross–cutting technology for enhancing hydrocarbon production in sedimentary formations and increasing heat exchange in crystalline geothermal systems. Whereas the primary measure of success is the ability to keep the newly generated fractures sufficiently open, long–term reservoir management requires a knowledge of the spatial extent, morphology, and distribution of the fractures — knowledge primarily informed by microseismic and ground deformation monitoring. To minimize the uncertainty associated with interpreting such data, we investigate through numerical simulation the usefulness of direct-current (DC) resistivity data for characterizing subsurface fractures with elevated electrical conductivity by considering a geophysical experiment consisting of a grounded current source deployed in a steel cased borehole. In doing so, the casing efficiently energizes the fractures with steady current. Finite element simulations of this experiment for a horizontal well intersecting a small set of vertical fractures indicate that the fractures manifest electrically in (at least) two ways: (1) a local perturbation in electric potential proximal to the fracture set, with limited farfield expression and (2) an overall reduction in the electric potential along the borehole casing due to enhanced current flow through the fractures into the surrounding formation. The change in casing potential results in a measurable effect that can be observed far from fractures themselves. Under these conditions, our results suggest that farfield, timelapse measurements of DC potentials can be interpreted by simple, linear inversion for a Coulomb charge distribution along the borehole path, including a local charge perturbation due to the fractures. As a result, this approach offers an inexpensive method for detecting and monitoring the time-evolution of electrically conducting fractures while

  13. The direct-current response of electrically conducting fractures excited by a grounded current source

    DOE PAGES

    Weiss, Chester J.; Aldridge, David F.; Knox, Hunter A.; ...

    2016-05-01

    Hydraulic fracture stimulation of low permeability reservoir rocks is an established and cross–cutting technology for enhancing hydrocarbon production in sedimentary formations and increasing heat exchange in crystalline geothermal systems. Whereas the primary measure of success is the ability to keep the newly generated fractures sufficiently open, long–term reservoir management requires a knowledge of the spatial extent, morphology, and distribution of the fractures — knowledge primarily informed by microseismic and ground deformation monitoring. To minimize the uncertainty associated with interpreting such data, we investigate through numerical simulation the usefulness of direct-current (DC) resistivity data for characterizing subsurface fractures with elevated electricalmore » conductivity by considering a geophysical experiment consisting of a grounded current source deployed in a steel cased borehole. In doing so, the casing efficiently energizes the fractures with steady current. Finite element simulations of this experiment for a horizontal well intersecting a small set of vertical fractures indicate that the fractures manifest electrically in (at least) two ways: (1) a local perturbation in electric potential proximal to the fracture set, with limited farfield expression and (2) an overall reduction in the electric potential along the borehole casing due to enhanced current flow through the fractures into the surrounding formation. The change in casing potential results in a measurable effect that can be observed far from fractures themselves. Under these conditions, our results suggest that farfield, timelapse measurements of DC potentials can be interpreted by simple, linear inversion for a Coulomb charge distribution along the borehole path, including a local charge perturbation due to the fractures. As a result, this approach offers an inexpensive method for detecting and monitoring the time-evolution of electrically conducting fractures while

  14. Electronics and photonics convergence on Si CMOS platform

    NASA Astrophysics Data System (ADS)

    Wada, Kazumi

    2004-07-01

    The present paper describes Si microphotonics and its current status of electronics and photonics convergence on Si platform based on monolithic integration using CMOS (Complementary Metal Oxide Semiconductor) technologies. The Si CMOS platform is advantageous over III-V semiconductor based platform because of a short time-lag between basic research and commercialization in terms of the standardized materials and processes. To implement photonic devices on the Si CMOS platform, it is important to reduce materials diversity in current photonics devices. Low loss SiNx waveguides with sharp bends, high performance strained Ge photodetectors for C+L band, and demultiplexer/multiplexer for WDM (wavelength division multiplexing) have been successfully implemented on the Si CMOS platform. The current targets are cost-effective OADMs (optical add-drop multiplexers) for optical communication and optical clocking for Si LSIs beyond Cu-low k technologies.

  15. Developments and Applications of High-Performance CCD and CMOS Imaging Arrays

    NASA Astrophysics Data System (ADS)

    Janesick, James; Putnam, Gloria

    2003-12-01

    For over 20 years, charge-coupled devices (CCDs) have dominated most digital imaging applications and markets. Today, complementary metal oxide semiconductor (CMOS) arrays are displacing CCDs in some applications, and this trend is expected to continue. Low cost, low power, on-chip system integration, and high-speed operation are unique features that have generated interest in CMOS arrays. This paper reviews current CCD and CMOS sensor developments and related applications. We compare fundamental performance parameters common to these technologies and describe why the CCD is considered a mature technology, whereas CMOS arrays have significant room for growth. The paper presents custom CMOS pixel designs and related fabrication processes that address performance deficiencies of the CCD in high-performance applications. We discuss areas of development for future CCD and CMOS imagers. The paper also briefly reviews hybrid imaging arrays that combine the advantages of CCD and CMOS, producing better sensors than either technology alone can provide.

  16. Miniaturized FDDA and CMOS Based Potentiostat for Bio-Applications

    PubMed Central

    Ghodsevali, Elnaz; Morneau-Gamache, Samuel; Mathault, Jessy; Landari, Hamza; Boisselier, Élodie; Boukadoum, Mounir; Gosselin, Benoit; Miled, Amine

    2017-01-01

    A novel fully differential difference CMOS potentiostat suitable for neurotransmitter sensing is presented. The described architecture relies on a fully differential difference amplifier (FDDA) circuit to detect a wide range of reduction-oxidation currents, while exhibiting low-power consumption and low-noise operation. This is made possible thanks to the fully differential feature of the FDDA, which allows to increase the source voltage swing without the need for additional dedicated circuitry. The FDDA also reduces the number of amplifiers and passive elements in the potentiostat design, which lowers the overall power consumption and noise. The proposed potentiostat was fabricated in 0.18 µm CMOS, with 1.8 V supply voltage. The device achieved 5 µA sensitivity and 0.99 linearity. The input-referred noise was 6.9 µVrms and the flicker noise was negligible. The total power consumption was under 55 µW. The complete system was assembled on a 20 mm × 20 mm platform that includes the potentiostat chip, the electrode terminals and an instrumentation amplifier for redox current buffering, once converted to a voltage by a series resistor. the chip dimensions were 1 mm × 0.5 mm and the other PCB components were off-chip resistors, capacitors and amplifiers for data acquisition. The system was successfully tested with ferricyanide, a stable electroactive compound, and validated with dopamine, a popular neurotransmitter. PMID:28394289

  17. Standard arc welders provide high amperage direct current source

    NASA Technical Reports Server (NTRS)

    Beasley, W. D.; Brooks, J. D.

    1966-01-01

    Standard arc welders or power supplies are hooked up in parallel or series connections to obtain an adequate supply of current or voltage for various purposes. This method provides maximum flexibility in a wide range of voltages and currents.

  18. DESIGN NOTE: A very high output resistance current source

    NASA Astrophysics Data System (ADS)

    Hayatleh, K.; Terzopoulos, N.; Hart, B. L.

    2007-01-01

    The vertical stacking of two identical sub-circuits—improved versions of a bipolar transistor configuration proposed by Baxandall and Swallow—driven by dual output current mirrors, facilitates the design of a current generator producing a direct current of 1 mA with an incremental output resistance exceeding 200 GΩ.

  19. Improving manufacturability of an rf graded channel CMOS process for wireless applications

    NASA Astrophysics Data System (ADS)

    Lamey, Daniel J.; Mackie, Troy; Liang, Han-Bin; Ma, Jun; Robert, Georges; Jasper, Craig; Ngo, David; Papworth, Ken; Cheng, Sunny; Wilcock, Christy; Gurrola, Rosemary; Spears, Edward; Yeung, Bruce

    1998-09-01

    Motorola's Graded Channel CMOS (GCMOS) provides a low cost and highly integrated solution for mixed-mode and RF applications. The GCMOS transistor has demonstrated performance advantages over standard CMOS processes with the same physical gate length. The graded channel, fabricated using lateral diffusion, provides a deep submicron Leff even with a gate length of 0.6 micrometer. The technology is constructed using a process that is fully compatible with standard CMOS manufacturing. However, in order to assure adequate threshold control, the lateral diffusions must be well-behaved. This means that both the channel implant and the source/drain implant must be truly self-aligned, requiring good control of the implants as well as the gate electrode profile. For aggressively designed GCMOS devices, small deviations of the implant beam from normal incidence can lead to unacceptable shifts in threshold. The sources of such error, and current industry standard machine tolerances for each, are discussed. Strategies for ensuring adequate control include a regimen of in-line process monitors, approximate error cancellation of the channel and source/drain implants, and the use of quadrature implants. By using these strategies a manufacturable process has been achieved.

  20. Low energy CMOS for space applications

    NASA Technical Reports Server (NTRS)

    Panwar, Ramesh; Alkalaj, Leon

    1992-01-01

    The current focus of NASA's space flight programs reflects a new thrust towards smaller, less costly, and more frequent space missions, when compared to missions such as Galileo, Magellan, or Cassini. Recently, the concept of a microspacecraft was proposed. In this concept, a small, compact spacecraft that weighs tens of kilograms performs focused scientific objectives such as imaging. Similarly, a Mars Lander micro-rover project is under study that will allow miniature robots weighing less than seven kilograms to explore the Martian surface. To bring the microspacecraft and microrover ideas to fruition, one will have to leverage compact 3D multi-chip module-based multiprocessors (MCM) technologies. Low energy CMOS will become increasingly important because of the thermodynamic considerations in cooling compact 3D MCM implementations and also from considerations of the power budget for space applications. In this paper, we show how the operating voltage is related to the threshold voltage of the CMOS transistors for accomplishing a task in VLSI with minimal energy. We also derive expressions for the noise margins at the optimal operating point. We then look at a low voltage CMOS (LVCMOS) technology developed at Stanford University which improves the power consumption over conventional CMOS by a couple of orders of magnitude and consider the suitability of the technology for space applications by characterizing its SEU immunity.

  1. Characterization of total ionizing dose damage in COTS pinned photodiode CMOS image sensors

    SciTech Connect

    Wang, Zujun Ma, Wuying; Huang, Shaoyan; Yao, Zhibin; Liu, Minbo; He, Baoping; Sheng, Jiangkun; Xue, Yuan; Liu, Jing

    2016-03-15

    The characterization of total ionizing dose (TID) damage in COTS pinned photodiode (PPD) CMOS image sensors (CISs) is investigated. The radiation experiments are carried out at a {sup 60}Co γ-ray source. The CISs are produced by 0.18-μm CMOS technology and the pixel architecture is 8T global shutter pixel with correlated double sampling (CDS) based on a 4T PPD front end. The parameters of CISs such as temporal domain, spatial domain, and spectral domain are measured at the CIS test system as the EMVA 1288 standard before and after irradiation. The dark current, random noise, dark signal non-uniformity (DSNU), photo response non-uniformity (PRNU), overall system gain, saturation output, dynamic range (DR), signal to noise ratio (SNR), quantum efficiency (QE), and responsivity versus the TID are reported. The behaviors of the tested CISs show remarkable degradations after radiation. The degradation mechanisms of CISs induced by TID damage are also analyzed.

  2. An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.

    PubMed

    Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18  μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology.

  3. Building strong partnerships with CMOs.

    PubMed

    Dye, Carson F

    2014-07-01

    CFOs and chief medical officers (CMOs) can build on common traits to form productive partnerships in guiding healthcare organizations through the changes affecting the industry. CFOs can strengthen bonds with CMOs by taking steps to engage physicians on their own turf--by visiting clinical locations and attending medical-executive committee meetings, for example. Steps CFOs can take to help CMOs become more acquainted with the financial operations of health systems include demonstrating the impact of clinical decisions on costs and inviting CMOs to attend finance-related meetings.

  4. Application of optical emission spectroscopy to high current proton sources

    NASA Astrophysics Data System (ADS)

    Castro, G.; Mazzaglia, M.; Nicolosi, D.; Mascali, D.; Reitano, R.; Zaniol, B.; Celona, L.; Leonardi, O.; Leone, F.; Naselli, E.; Neri, L.; Torrisi, G.; Gammino, S.

    2017-07-01

    Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. With respect to other diagnostics, it also can characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as "testbench" of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile, along with perspectives for further upgrades of the OES diagnostics system.

  5. CMOS-compatible spintronic devices: a review

    NASA Astrophysics Data System (ADS)

    Makarov, Alexander; Windbacher, Thomas; Sverdlov, Viktor; Selberherr, Siegfried

    2016-11-01

    For many decades CMOS devices have been successfully scaled down to achieve higher speed and increased performance of integrated circuits at lower cost. Today’s charge-based CMOS electronics encounters two major challenges: power dissipation and variability. Spintronics is a rapidly evolving research and development field, which offers a potential solution to these issues by introducing novel ‘more than Moore’ devices. Spin-based magnetoresistive random-access memory (MRAM) is already recognized as one of the most promising candidates for future universal memory. Magnetic tunnel junctions, the main elements of MRAM cells, can also be used to build logic-in-memory circuits with non-volatile storage elements on top of CMOS logic circuits, as well as versatile compact on-chip oscillators with low power consumption. We give an overview of CMOS-compatible spintronics applications. First, we present a brief introduction to the physical background considering such effects as magnetoresistance, spin-transfer torque (STT), spin Hall effect, and magnetoelectric effects. We continue with a comprehensive review of the state-of-the-art spintronic devices for memory applications (STT-MRAM, domain wall-motion MRAM, and spin-orbit torque MRAM), oscillators (spin torque oscillators and spin Hall nano-oscillators), logic (logic-in-memory, all-spin logic, and buffered magnetic logic gate grid), sensors, and random number generators. Devices with different types of resistivity switching are analyzed and compared, with their advantages highlighted and challenges revealed. CMOS-compatible spintronic devices are demonstrated beginning with predictive simulations, proceeding to their experimental confirmation and realization, and finalized by the current status of application in modern integrated systems and circuits. We conclude the review with an outlook, where we share our vision on the future applications of the prospective devices in the area.

  6. Synchronization between two coupled direct current glow discharge plasma sources

    SciTech Connect

    Chaubey, Neeraj; Mukherjee, S.; Sen, A.; Sekar Iyengar, A. N.

    2015-02-15

    Experimental results on the nonlinear dynamics of two coupled glow discharge plasma sources are presented. A variety of nonlinear phenomena including frequency synchronization and frequency pulling are observed as the coupling strength is varied. Numerical solutions of a model representation of the experiment consisting of two coupled asymmetric Van der Pol type equations are found to be in good agreement with the observed results.

  7. Current challenges in open-source bioimage informatics.

    PubMed

    Cardona, Albert; Tomancak, Pavel

    2012-06-28

    We discuss the advantages and challenges of the open-source strategy in biological image analysis and argue that its full impact will not be realized without better support and recognition of software engineers' contributions to the biological sciences and more support of this development model from funders and institutions.

  8. Improvement to the signaling interface for CMOS pixel sensors

    NASA Astrophysics Data System (ADS)

    Shi, Zhan; Tang, Zhenan; Feng, Chong; Cai, Hong

    2016-10-01

    The development of the readout speed of CMOS pixel sensors (CPS) is motivated by the demanding requirements of future high energy physics (HEP) experiments. As the interface between CPS and the data acquisition (DAQ) system, which inputs clock from the DAQ system and outputs data from CPS, the signaling interface should also be improved in terms of data rates. Meanwhile, the power consumption of the signaling interface should be maintained as low as possible. Consequently, a reduced swing differential signaling (RSDS) driver was adopted instead of a low-voltage differential signaling (LVDS) driver to transmit data from CPS to the DAQ system. In order to increase the capability of data rates, a serial source termination technique was employed. A LVDS/RSDS receiver was employed for transmitting clock from the DAQ system to CPS. A new method of generating hysteresis and a special current comparator were used to achieve a higher speed with lower power consumption. The signaling interface was designed and submitted for fabrication in a 0.18 μm CMOS image sensor (CIS) process. Measurement results indicate that the RSDS driver and the LVDS receiver can operate correctly at a data rate of 2 Gb/s with a power consumption of 19.1 mW.

  9. Monolithic integration of a plasmonic sensor with CMOS technology

    NASA Astrophysics Data System (ADS)

    Shakoor, Abdul; Cheah, Boon C.; Hao, Danni; Al-Rawhani, Mohammed; Nagy, Bence; Grant, James; Dale, Carl; Keegan, Neil; McNeil, Calum; Cumming, David R. S.

    2017-02-01

    Monolithic integration of nanophotonic sensors with CMOS detectors can transform the laboratory based nanophotonic sensors into practical devices with a range of applications in everyday life. In this work, by monolithically integrating an array of gold nanodiscs with the CMOS photodiode we have developed a compact and miniaturized nanophotonic sensor system having direct electrical read out. Doing so eliminates the need of expensive and bulky laboratory based optical spectrum analyzers used currently for measurements of nanophotonic sensor chips. The experimental optical sensitivity of the gold nanodiscs is measured to be 275 nm/RIU which translates to an electrical sensitivity of 5.4 V/RIU. This integration of nanophotonic sensors with the CMOS electronics has the potential to revolutionize personalized medical diagnostics similar to the way in which the CMOS technology has revolutionized the electronics industry.

  10. Single photon detection and localization accuracy with an ebCMOS camera

    NASA Astrophysics Data System (ADS)

    Cajgfinger, T.; Dominjon, A.; Barbier, R.

    2015-07-01

    The CMOS sensor technologies evolve very fast and offer today very promising solutions to existing issues facing by imaging camera systems. CMOS sensors are very attractive for fast and sensitive imaging thanks to their low pixel noise (1e-) and their possibility of backside illumination. The ebCMOS group of IPNL has produced a camera system dedicated to Low Light Level detection and based on a 640 kPixels ebCMOS with its acquisition system. After reminding the principle of detection of an ebCMOS and the characteristics of our prototype, we confront our camera to other imaging systems. We compare the identification efficiency and the localization accuracy of a point source by four different photo-detection devices: the scientific CMOS (sCMOS), the Charge Coupled Device (CDD), the Electron Multiplying CCD (emCCD) and the Electron Bombarded CMOS (ebCMOS). Our ebCMOS camera is able to identify a single photon source in less than 10 ms with a localization accuracy better than 1 μm. We report as well efficiency measurement and the false positive identification of the ebCMOS camera by identifying more than hundreds of single photon sources in parallel. About 700 spots are identified with a detection efficiency higher than 90% and a false positive percentage lower than 5. With these measurements, we show that our target tracking algorithm can be implemented in real time at 500 frames per second under a photon flux of the order of 8000 photons per frame. These results demonstrate that the ebCMOS camera concept with its single photon detection and target tracking algorithm is one of the best devices for low light and fast applications such as bioluminescence imaging, quantum dots tracking or adaptive optics.

  11. High brightness negative ion sources with high emission current density

    SciTech Connect

    Vadim Dudnikov

    2002-10-18

    Through the development of Charge Exchange Injection [1] and Surface Plasma Sources (SPS) with Cesium Catalysis [2,3,4,5] the possibility for the accumulation of a high brightness proton beam in circular accelerators was increased greatly, and now it is more than sufficient for all real applications. The combination of the SPS with charge-exchange injection improved large accelerators operation and has permitted beam accumulation up to space-charge limit and overcome this limit several times [6]. The early SPS for accelerators have been in operation without modification for {approx}25 years. in this note an attention is concentrated on the seldom-discussed distinctive features of high brightness beam formation in noiseless regimes of negative ion source operation. Beam quality enhancement up to the level j/T > 1 A/cm{sup 2} eV is possible by optimization of negative ion generation, extraction, and transportation in SPS with cesium catalysis. Advanced version of the SPS for accelerators will be described. Features of negative ion beam formation, transportation, space-charge neutralization-overneutralization, and instability damping will be considered. Practical aspects of SPS operation and high brightness beam production will be discussed.

  12. Fully depleted CMOS pixel sensor development and potential applications

    SciTech Connect

    Baudot, J.; Kachel, M.

    2015-07-01

    CMOS pixel sensors are often opposed to hybrid pixel sensors due to their very different sensitive layer. In standard CMOS imaging processes, a thin (about 20 μm) low resistivity epitaxial layer acts as the sensitive volume and charge collection is mostly driven by thermal agitation. In contrast, the so-called hybrid pixel technology exploits a thick (typically 300 μm) silicon sensor with high resistivity allowing for the depletion of this volume, hence charges drift toward collecting electrodes. But this difference is fading away with the recent availability of some CMOS imaging processes based on a relatively thick (about 50 μm) high resistivity epitaxial layer which allows for full depletion. This evolution extents the range of applications for CMOS pixel sensors where their known assets, high sensitivity and granularity combined with embedded signal treatment, could potentially foster breakthrough in detection performances for specific scientific instruments. One such domain is the Xray detection for soft energies, typically below 10 keV, where the thin sensitive layer was previously severely impeding CMOS sensor usage. Another application becoming realistic for CMOS sensors, is the detection in environment with a high fluence of non-ionizing radiation, such as hadron colliders. However, when considering highly demanding applications, it is still to be proven that micro-circuits required to uniformly deplete the sensor at the pixel level, do not mitigate the sensitivity and efficiency required. Prototype sensors in two different technologies with resistivity higher than 1 kΩ, sensitive layer between 40 and 50 μm and featuring pixel pitch in the range 25 to 50 μm, have been designed and fabricated. Various biasing architectures were adopted to reach full depletion with only a few volts. Laboratory investigations with three types of sources (X-rays, β-rays and infrared light) demonstrated the validity of the approach with respect to depletion, keeping a

  13. Low Temperature Heat Source Utilization Current and Advanced Technology

    SciTech Connect

    Anderson, James H. Jr.; Dambly, Benjamin W.

    1992-06-01

    Once a geothermal heat source has been identified as having the potential for development, and its thermal, physical, and chemical characteristics have been determined, a method of utilization must be decided upon. This compendium will touch upon some of these concerns, and hopefully will provide the reader with a better understanding of technologies being developed that will be applicable to geothermal development in East Africa, as well as other parts of the world. The appendices contain detailed reports on Down-the-Well Turbo Pump, The Vapor-Turbine Cycle for Geothermal Power Generation, Heat Exchanger Design for Geothermal Power Plants, and a Feasibility Study of Combined Power and Water Desalting Plant Using Hot Geothermal Water. [DJE-2005

  14. What's New in Software? Current Sources of Information Boost Effectiveness of Computer-Assisted Instruction.

    ERIC Educational Resources Information Center

    Ellsworth, Nancy J.

    1990-01-01

    This article reviews current resources on computer-assisted instruction. Included are sources of software and hardware evaluations, advances in current technology, research, an information hotline, and inventories of available technological assistance. (DB)

  15. High-speed CMOS optical communication using silicon light emitters

    NASA Astrophysics Data System (ADS)

    Goosen, Marius E.; Venter, Petrus J.; du Plessis, Monuko; Nell, Ilse J.; Bogalecki, Alfons W.; Rademeyer, Pieter

    2011-01-01

    The idea of moving CMOS into the mainstream optical domain remains an attractive one. In this paper we discuss our recent advances towards a complete silicon optical communication solution. We prove that transmission of baseband data at multiples of megabits per second rates are possible using improved silicon light sources in a completely native standard CMOS process with no post processing. The CMOS die is aligned to a fiber end and the light sources are directly modulated. An optical signal is generated and transmitted to a silicon Avalanche Photodiode (APD) module, received and recovered. Signal detectability is proven through eye diagram measurements. The results show an improvement of more than tenfold over our previous results, also demonstrating the fastest optical communication from standard CMOS light sources. This paper presents an all silicon optical data link capable of 2 Mb/s at a bit error rate of 10-10, or alternatively 1 Mb/s at a bit error rate of 10-14. As the devices are not operating at their intrinsic switching speed limit, we believe that even higher transmission rates are possible with complete integration of all components in CMOS.

  16. Novel digital logic gate for high-performance CMOS imaging system

    NASA Astrophysics Data System (ADS)

    Chung, Hoon H.; Joo, Youngjoong

    2004-06-01

    In these days, the CMOS image sensors are commonly used in many low resolution applications because the CMOS imaging system has several advantages against the conventional CCD imaging system. However, there are still several problems for the realization of the single-chip CMOS imaging system. One main problem is the substrate coupling noise, which is caused by the digital switching noise. Because the CMOS image sensors share the same substrate with surrounding digital circuit, it is difficult for the CMOS image sensor to get a good performance. In order to investigate the substrate coupling noise effect of the CMOS image sensor, the conventional CMOS logic, C-CBL (Complementary-Current balanced logic) and proposed low switching noise logic are simulated and compared. Consequently, the proposed logic compensates not only the large digital switching noise of conventional CMOS logic ,but also the huge power consumption of the C-CBL. Both the total instantaneous current behaviors on the power supply and the peak-to-peak voltages of the substrate voltage variation (di/dt noise) are investigated. The simulation is performed by AMI 0.5μm CMOS technology.

  17. An excitation signal source with anti-interference ability for eddy current testing

    NASA Astrophysics Data System (ADS)

    Jiang, Guodong; Li, Po

    2015-02-01

    An eddy current excitation signal source was designed based on the linear control theory. By analyzing the interference and characteristics of signal source, a multi-input-single-output (MISO) feedback control system was designed and created using a lock-in amplifier, and an eddy current sensor was applied in the feedback loop of the system. As a result, the noise in the loop circuit was suppressed; this resolved the current instability problem in eddy current sensor. Furthermore, a mathematical model was established, and the stability and bandwidth of the system were verified by simulations. Compared with the traditional signal sources, experimental results show that this signal source had steadier current output, smaller temperature drift and stronger load capability. Therefore, the foil thickness measurement based on this signal source had a very high accuracy.

  18. Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging.

    PubMed

    Esposito, M; Anaxagoras, T; Konstantinidis, A C; Zheng, Y; Speller, R D; Evans, P M; Allinson, N M; Wells, K

    2014-07-07

    Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this

  19. Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

    NASA Astrophysics Data System (ADS)

    Esposito, M.; Anaxagoras, T.; Konstantinidis, A. C.; Zheng, Y.; Speller, R. D.; Evans, P. M.; Allinson, N. M.; Wells, K.

    2014-07-01

    Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this

  20. Effect due to plasma electrode adsorbates upon the negative ion current and electron current extracted from a negative ion source

    NASA Astrophysics Data System (ADS)

    Bacal, M.; Wada, M.

    2017-08-01

    The intensity of negative hydrogen (H-) ion current and that of electron current extracted from a negative ion source show different characteristics against the change in plasma electrode bias depending upon the material covering the plasma electrode surface. The knowledge of these characteristics is of importance for a proper design of an efficient H- ion source. This paper discusses this subject based upon two kind of experiments i) experiments with plasma electrodes covered with tungsten or tantalum evaporated from filaments made of these metals ii) experiments with caesium covered plasma electrode. The tantalum and caesium covered plasma electrodes lead to an enhancement of the extracted H- ion current by a factor of 2 compared to the tungsten coverage on the plasma electrode. The electron current is also affected by the material covering the plasma electrode. The reasons for observing these characteristics are also elucidated.

  1. Note: Development of 9 A current source for precise resistance measurement method.

    PubMed

    Štambuk, Igor; Malarić, Roman

    2012-10-01

    In this Note, design of voltage controlled current source intended to be used in precise resistance measurement system in the range from 0.1 mΩ to 10 Ω is presented. The design specifications of current source include gross-tuning of current in the range from 0.1 mA to 9 A, low noise, low temperature coefficient, and short term stability better than 50 ppm. The realized current source has achieved better short term stability than comparable commercial devices.

  2. A CMOS compatible, ferroelectric tunnel junction.

    PubMed

    Ambriz Vargas, Fabian; Kolhatkar, Gitanjali; Broyer, Maxime; Hadj Youssef, Azza; Nouar, Rafik; Sarkissian, Andranik; Thomas, Reji; Gomez-Yanez, Carlos; Gauthier, Marc A; Ruediger, Andreas

    2017-04-03

    In recent years, the experimental demonstration of Ferroelectric Tunnel Junctions (FTJ) based on perovskite tunnel barriers has been reported. However, integrating these perovskite materials into conventional silicon memory technology remains challenging due to their lack of compatibility with the complementary metal oxide semiconductor process (CMOS). The present communication reports the fabrication of an FTJ based on a CMOS compatible tunnel barrier Hf0.5Zr0.5O2 (6 unit cells thick) on an equally CMOS compatible TiN electrode. Analysis of the FTJ by grazing angle incidence X-ray diffraction confirmed the formation of the non-centrosymmetric orthorhombic phase (Pbc2_1, ferroelectric phase). The FTJ characterization is followed by the reconstruction of the electrostatic potential profile in the as-grown TiN/Hf0.5Zr0.5O2/Pt heterostructure. A direct tunneling current model across a trapezoidal barrier was used to correlate the electronic and electrical properties of our FTJ devices. The good agreement between the experimental and the theoretical model attests to the tunneling electroresistance effect (TER) in our FTJ device. A TER ratio of ~15 was calculated for the present FTJ device at low read voltage (+0.2 V). This study makes Hf0.5Zr0.5O2 a promising candidate for integration into conventional Si memory technology.

  3. A Novel Current Angle Control Scheme in a Current Source Inverter Fed Permanent Magnet Synchronous Motor Drive for Automotive Applications

    SciTech Connect

    Tang, Lixin; Su, Gui-Jia

    2011-01-01

    This paper describes a novel speed control scheme to operate a current source inverter (CSI) driven surface-mounted permanent magnet synchronous machine (SPMSM) for hybrid electric vehicles (HEVs) applications. The idea is to use the angle of the current vector to regulate the rotor speed while keeping the two dc-dc converter power switches on all the time to boost system efficiency. The effectiveness of the proposed scheme was verified with a 3 kW CSI-SPMSM drive prototype.

  4. Principle and modelling of Transient Current Technique for interface traps characterization in monolithic pixel detectors obtained by CMOS-compatible wafer bonding

    NASA Astrophysics Data System (ADS)

    Bronuzzi, J.; Mapelli, A.; Moll, M.; Sallese, J. M.

    2016-08-01

    In the framework of monolithic silicon radiation detectors, a fabrication process based on a recently developed silicon wafer bonding technique at low temperature was proposed. Ideally, this new process would enable direct bonding of a read-out electronic chip wafer on a highly resistive silicon substrate wafer, which is expected to present many advantages since it would combine high performance IC's with high sensitive ultra-low doped bulk silicon detectors. But electrical properties of the bonded interface are critical for this kind of application since the mobile charges generated by radiation inside the bonded bulk are expected to transit through the interface in order to be collected by the read-out electronics. In this work, we propose to explore and develop a model for the so-called Transient Current Technique (TCT) to identify the presence of deep traps at the bonded interface. For this purpose, we consider a simple PIN diode reversely biased where the ultra-low doped active region of interest is set in full depletion. In a first step, Synopsys Sentaurus TCAD is used to evaluate the soundness of this technique for interface traps characterization such as it may happen in bonded interfaces. Next, an analytical model is developed in details to give a better insight into the physics behind the TCT for interface layers. Further, this can be used as a simple tool to evidence what are the relevant parameters influencing the TCT signal and to set the basis for preliminary characterizations.

  5. Removal of Direct Current Link Harmonic Ripple in Single Phase Voltage Source Inverter Systems Using Supercapacitors

    DTIC Science & Technology

    2016-09-01

    CURRENT LINK HARMONIC RIPPLE IN SINGLE-PHASE VOLTAGE SOURCE INVERTER SYSTEMS USING SUPERCAPACITORS by Gabriel D. Hernandez September 2016...REMOVAL OF DIRECT CURRENT LINK HARMONIC RIPPLE IN SINGLE- PHASE VOLTAGE SOURCE INVERTER SYSTEMS USING SUPERCAPACITORS 5. FUNDING NUMBERS 6...bank as the only DC energy storage device, the DC link voltage ripple causes a second-order harmonic ripple in battery current that leads to a

  6. CMOS array design automation techniques

    NASA Technical Reports Server (NTRS)

    Lombardi, T.; Feller, A.

    1976-01-01

    The design considerations and the circuit development for a 4096-bit CMOS SOS ROM chip, the ATL078 are described. Organization of the ATL078 is 512 words by 8 bits. The ROM was designed to be programmable either at the metal mask level or by a directed laser beam after processing. The development of a 4K CMOS SOS ROM fills a void left by available ROM chip types, and makes the design of a totally major high speed system more realizable.

  7. Improved Signal Chains for Readout of CMOS Imagers

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Hancock, Bruce; Cunningham, Thomas

    2009-01-01

    An improved generic design has been devised for implementing signal chains involved in readout from complementary metal oxide/semiconductor (CMOS) image sensors and for other readout integrated circuits (ICs) that perform equivalent functions. The design applies to any such IC in which output signal charges from the pixels in a given row are transferred simultaneously into sampling capacitors at the bottoms of the columns, then voltages representing individual pixel charges are read out in sequence by sequentially turning on column-selecting field-effect transistors (FETs) in synchronism with source-follower- or operational-amplifier-based amplifier circuits. The improved design affords the best features of prior source-follower-and operational- amplifier-based designs while overcoming the major limitations of those designs. The limitations can be summarized as follows: a) For a source-follower-based signal chain, the ohmic voltage drop associated with DC bias current flowing through the column-selection FET causes unacceptable voltage offset, nonlinearity, and reduced small-signal gain. b) For an operational-amplifier-based signal chain, the required bias current and the output noise increase superlinearly with size of the pixel array because of a corresponding increase in the effective capacitance of the row bus used to couple the sampled column charges to the operational amplifier. The effect of the bus capacitance is to simultaneously slow down the readout circuit and increase noise through the Miller effect.

  8. CMOS Conductometric System for Growth Monitoring and Sensing of Bacteria.

    PubMed

    Lei Yao; Lamarche, P; Tawil, N; Khan, R; Aliakbar, A M; Hassan, M H; Chodavarapu, V P; Mandeville, R

    2011-06-01

    We present the design and implementation of a prototype complementary metal-oxide semiconductor (CMOS) conductometric integrated circuit (IC) for colony growth monitoring and specific sensing of Escherichia coli (E. coli) bacteria. The detection of E. coli is done by employing T4 bacteriophages as receptor organisms. The conductometric system operates by measuring the resistance of the test sample between the electrodes of a two-electrode electrochemical system (reference electrode and working electrode). The CMOS IC is fabricated in a TSMC 0.35-μm process and uses a current-to-frequency (I to F) conversion circuit to convert the test sample resistance into a digital output modulated in frequency. Pulsewidth control (one-shot circuit) is implemented on-chip to control the pulsewidth of the output digital signal. The novelty in the current work lies in the ability of the CMOS sensor system to monitor very low initial concentrations of bacteria (4×10(2) to 4×10(4) colony forming unit (CFU)/mL). The CMOS system is also used to record the interaction between E. coli and its specific receptor T4 bacteriophage. The prototype CMOS IC consumes an average power of 1.85 mW with a 3.3-V dc power supply.

  9. High current Cu3P liquid metal ion source using a novel extractor configuration

    NASA Astrophysics Data System (ADS)

    Higuchi-Rusli, R. H.; Corelli, J. C.

    1987-12-01

    It has been found that by utilizing a sharp needle for the extractor electrode in close proximity to the source tip wetted with Cu3P liquid alloy, a large increase (factor ˜300) in ion current is observed in comparison to standard liquid metal ion sources (LMIS's). In standard previously used LMIS's the extractor electrode was a flat plane with a circular hole centered on the source needle tip. This new high current source has important applications in focused and broad ion beam deposition systems.

  10. Growth of carbon nanotubes on fully processed silicon-on-insulator CMOS substrates.

    PubMed

    Haque, M Samiul; Ali, S Zeeshan; Guha, P K; Oei, S P; Park, J; Maeng, S; Teo, K B K; Udrea, F; Milne, W I

    2008-11-01

    This paper describes the growth of Carbon Nanotubes (CNTs) both aligned and non-aligned on fully processed CMOS substrates containing high temperature tungsten metallization. While the growth method has been demonstrated in fabricating CNT gas sensitive layers for high temperatures SOI CMOS sensors, it can be employed in a variety of applications which require the use of CNTs or other nanomaterials with CMOS electronics. In our experiments we have grown CNTs both on SOI CMOS substrates and SOI CMOS microhotplates (suspended on membranes formed by post-CMOS deep RIE etching). The fully processed SOI substrates contain CMOS devices and circuits and additionally, some wafers contained high current LDMOSFETs and bipolar structures such as Lateral Insulated Gate Bipolar Transistors. All these devices were used as test structures to investigate the effect of additional post-CMOS processing such as CNT growth, membrane formation, high temperature annealing, etc. Electrical characterisation of the devices with CNTs were performed along with SEM and Raman spectroscopy. The CNTs were grown both at low and high temperatures, the former being compatible with Aluminium metallization while the latter being possible through the use of the high temperature CMOS metallization (Tungsten). In both cases we have found that there is no change in the electrical behaviour of the CMOS devices, circuits or the high current devices. A slight degradation of the thermal performance of the CMOS microhotplates was observed due to the extra heat dissipation path created by the CNT layers, but this is expected as CNTs exhibit a high thermal conductance. In addition we also observed that in the case of high temperature CNT growth a slight degradation in the manufacturing yield was observed. This is especially the case where large area membranes with a diameter in excess of 500 microns are used.

  11. High-resolution extremity cone-beam CT with a CMOS detector: task-based optimization of scintillator thickness

    NASA Astrophysics Data System (ADS)

    Cao, Q.; Brehler, M.; Sisniega, A.; Stayman, J. W.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2017-03-01

    Purpose: CMOS x-ray detectors offer small pixel sizes and low electronic noise that may support the development of novel high-resolution imaging applications of cone-beam CT (CBCT). We investigate the effects of CsI scintillator thickness on the performance of CMOS detectors in high resolution imaging tasks, in particular in quantitative imaging of bone microstructure in extremity CBCT. Methods: A scintillator thickness-dependent cascaded systems model of CMOS x-ray detectors was developed. Detectability in low-, high- and ultra-high resolution imaging tasks (Gaussian with FWHM of 250 μm, 80 μm and 40 μm, respectively) was studied as a function of scintillator thickness using the theoretical model. Experimental studies were performed on a CBCT test bench equipped with DALSA Xineos3030 CMOS detectors (99 μm pixels) with CsI scintillator thicknesses of 400 μm and 700 μm, and a 0.3 FS compact rotating anode x-ray source. The evaluation involved a radiographic resolution gauge (0.6-5.0 lp/mm), a 127 μm tungsten wire for assessment of 3D resolution, a contrast phantom with tissue-mimicking inserts, and an excised fragment of human tibia for visual assessment of fine trabecular detail. Results: Experimental studies show 35% improvement in the frequency of 50% MTF modulation when using the 400 μm scintillator compared to the standard nominal CsI thickness of 700 μm. Even though the high-frequency DQE of the two detectors is comparable, theoretical studies show a 14% to 28% increase in detectability index (d'2) of high- and ultra- high resolution tasks, respectively, for the detector with 400 μm CsI compared to 700 μm CsI. Experiments confirm the theoretical findings, showing improvements with the adoption of 400 μm panel in the visibility of the radiographic pattern (2x improvement in peak-to-through distance at 4.6 lp/mm) and a 12.5% decrease in the FWHM of the tungsten wire. Reconstructions of the tibial plateau reveal enhanced visibility of trabecular

  12. CMOS-compatible photonic devices for single-photon generation

    NASA Astrophysics Data System (ADS)

    Xiong, Chunle; Bell, Bryn; Eggleton, Benjamin J.

    2016-09-01

    Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal-oxide-semiconductor (CMOS)-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon) and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

  13. Letter Report on 500 nA Pulsed Current from Field Ionization Source

    SciTech Connect

    Ellsworth, Jennifer L.

    2013-12-12

    We recently produced a milestone 500 nA of pulsed current using 40 Ir field ionizer electrodes in our ion source. In conclusion, we have produced the milestone pulsed current of 500 nA using 40 electrochemically etched iridium tips in a field ionization source. The pulsed current output is repeatable and scales as expected with gas fill pressure and bias voltage. We expect these current will be sufficient to produce neutral yields of 1∙107 DT n/s.

  14. The performance of integrated transconductance amplifiers as variable current sources for bio-electric impedance measurements.

    PubMed

    Smith, D N

    1992-01-01

    Multiple applied current impedance measurement systems require numbers of current sources which operate simultaneously at the same frequency and within the same phase but at variable amplitudes. Investigations into the performance of some integrated operational transconductance amplifiers as variable current sources are described. Measurements of breakthrough, non-linearity and common-mode output levels for LM13600, NE5517 and CA3280 were carried out. The effects of such errors on the overall performance and stability of multiple current systems when driving floating loads are considered.

  15. Four-dimensional ultrasound current source density imaging of a dipole field

    PubMed Central

    Wang, Z. H.; Olafsson, R.; Ingram, P.; Li, Q.; Qin, Y.; Witte, R. S.

    2011-01-01

    Ultrasound current source density imaging (UCSDI) potentially transforms conventional electrical mapping of excitable organs, such as the brain and heart. For this study, we demonstrate volume imaging of a time-varying current field by scanning a focused ultrasound beam and detecting the acoustoelectric (AE) interaction signal. A pair of electrodes produced an alternating current distribution in a special imaging chamber filled with a 0.9% NaCl solution. A pulsed 1 MHz ultrasound beam was scanned near the source and sink, while the AE signal was detected on remote recording electrodes, resulting in time-lapsed volume movies of the alternating current distribution. PMID:21998486

  16. Status of high current ion source operation at the GSI accelerator facility.

    PubMed

    Hollinger, R; Galonska, M; Gutermuth, B; Heymach, F; Krichbaum, H; Leible, K-D; Ochs, K; Schäffer, P; Schäffer, S; Spädtke, P; Stork, M; Wesp, A; Mayr, R

    2008-02-01

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2 keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  17. Status of high current ion source operation at the GSI accelerator facility

    SciTech Connect

    Hollinger, R.; Galonska, M.; Gutermuth, B.; Heymach, F.; Krichbaum, H.; Leible, K.-D.; Ochs, K.; Schaeffer, P.; Schaeffer, S.; Spaedtke, P.; Stork, M.; Wesp, A.; Mayr, R.

    2008-02-15

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2 keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  18. Status of high current ion source operation at the GSI accelerator facilitya)

    NASA Astrophysics Data System (ADS)

    Hollinger, R.; Galonska, M.; Gutermuth, B.; Heymach, F.; Krichbaum, H.; Leible, K.-D.; Ochs, K.; Schäffer, P.; Schäffer, S.; Spädtke, P.; Stork, M.; Wesp, A.; Mayr, R.

    2008-02-01

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  19. Ion energy spread and current measurements of the rf-driven multicusp ion source

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Gough, R. A.; Kunkel, W. B.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Sun, L.; Vujic, J.; Williams, M. D.; Wutte, D.

    1997-03-01

    Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of 80 mA/cm2 can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges.

  20. A Test of Source-Surfae Model Predictions of Heliospheric Current Sheet Inclination

    NASA Technical Reports Server (NTRS)

    Burton, M. E.; Smith, E. J.; Crooker, N. U.; Siscoe, G. L.

    1993-01-01

    The orientation of the heliospheric current sheet predicted from a source surfae model is compared with the orientation determined from minimum variance analysis of ISEE-3 magnetic field data at 1 AU near solar maximum.

  1. Architectures for Low-noise CMOS Electronic Imaging

    NASA Astrophysics Data System (ADS)

    Kawahito, Shoji

    This chapter discusses various types of signal readout architectures for CMOS image sensors, implementing ultra-low-noise conversion of photo-generated charge packets into digital output values. It is based on a detailed analysis of the different noise sources in a CMOS imager, the noise responses of column noise cancelling circuits using correlated double sampling (CDS) and correlated multiple sampling (CMS) techniques and a noiseless signal readout technique using a precise digitizer. Finally, a practical example for the design of a CMOS image sensor with single-photon resolution is presented, and the technological requirements for meeting the condition for room-temperature readout noise of significantly less than 1 electron are discussed.

  2. Low-noise pulsed current source for magnetic-field measurements of magnets for accelerators

    NASA Astrophysics Data System (ADS)

    Omelyanenko, M. M.; Borisov, V. V.; Donyagin, A. M.; Khodzhibagiyan, H. G.; Kostromin, S. A.; Makarov, A. A.; Shemchuk, A. V.

    2017-01-01

    The schematic diagram, design, and technical characteristics of the pulsed current source developed and produced for the magnetic-field measurement system of superconducting magnets for accelerators are described. The current source is based on the current regulator with pass transistor bank in the linear mode. Output current pulses (0-100 A) are produced by utilizing the energy of the preliminarily charged capacitor bank (5-40 V), which is additionally charged between pulses. The output current does not have the mains frequency and harmonics ripple. The relative noise level is less than-100 dB (or 10-5) of RMS value (it is defined as the ratio of output RMS noise current to a maximal output current of 100 A within the operating bandwidth, expressed in dB). The work was performed at the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR).

  3. High current density beamlets from RF Argon source for heavy ion fusion applications

    SciTech Connect

    Kwan, J.W.; Grote, D.P.; Westenskow, G.

    2003-08-01

    In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm{sup 2}. The normalized emittance of 0.02 {pi}-mm-mrad corresponds to an equivalent ion temperature of 2.4 eV. These results showed that the RF argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for HIF application.

  4. High Current Density Beamlets from an RF Argon Source for Heavy Ion Fusion Applications

    SciTech Connect

    Kwan, J W; Grote, D P; Westenskow, G A

    2003-09-04

    In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm{sup 2}. The normalized emittance of 0.02 {pi}-mm-mrad corresponds to an equivalent ion temperature of 2.4 eV. These results showed that the RF argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for HIF application.

  5. Partially coherent fundamental Gaussian wave generated by a fluctuating planar current source.

    PubMed

    Seshadri, S R

    2010-06-01

    The propagation characteristics of a spatially localized electromagnetic wave produced by a planar current source of different states of spatial coherence are analyzed by the use of a Gaussian Schell-model source. A linearly polarized fundamental electromagnetic Gaussian wave with the electric field perpendicular to the direction of propagation is treated. The effects of the degree of coherence of the source distribution on the radiation intensity distribution and the total radiated power are determined.

  6. Method and system for a gas tube-based current source high voltage direct current transmission system

    DOEpatents

    She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  7. Large-area low-temperature ultrananocrystaline diamond (UNCD) films and integration with CMOS devices for monolithically integrated diamond MEMD/NEMS-CMOS systems.

    SciTech Connect

    Sumant, A.V.; Auciello, O.; Yuan, H.-C; Ma, Z.; Carpick, R. W.; Mancini, D. C.; Univ. of Wisconsin; Univ. of Pennsylvania

    2009-05-01

    Because of exceptional mechanical, chemical, and tribological properties, diamond has a great potential to be used as a material for the development of high-performance MEMS and NEMS such as resonators and switches compatible with harsh environments, which involve mechanical motion and intermittent contact. Integration of such MEMS/NEMS devices with complementary metal oxide semiconductor (CMOS) microelectronics will provide a unique platform for CMOS-driven commercial MEMS/NEMS. The main hurdle to achieve diamond-CMOS integration is the relatively high substrate temperatures (600-800 C) required for depositing conventional diamond thin films, which are well above the CMOS operating thermal budget (400 C). Additionally, a materials integration strategy has to be developed to enable diamond-CMOS integration. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, is currently the only microwave plasma chemical vapor deposition (MPCVD) grown diamond film that can be grown at 400 C, and still retain exceptional mechanical, chemical, and tribological properties comparable to that of single crystal diamond. We have developed a process based on MPCVD to synthesize UNCD films on up to 200 mm in diameter CMOS wafers, which will open new avenues for the fabrication of monolithically integrated CMOS-driven MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 C in a MPCVD system, using Ar-rich/CH4 gas mixture. The CMOS devices on the wafers were characterized before and after UNCD deposition. All devices were performing to specifications with very small degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-9% were observed.

  8. Current source enhancements in Electrical Impedance Spectroscopy (EIS) to cancel unwanted capacitive effects

    NASA Astrophysics Data System (ADS)

    Zarafshani, Ali; Bach, Thomas; Chatwin, Chris; Xiang, Liangzhong; Zheng, Bin

    2017-03-01

    Electrical Impedance Spectroscopy (EIS) has emerged as a non-invasive imaging modality to detect and quantify functional or electrical properties related to the suspicious tumors in cancer screening, diagnosis and prognosis assessment. A constraint on EIS systems is that the current excitation system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIS is an ill-posed inverse problem which depends on the noise level in EIS measured data and regularization parameter in the reconstruction algorithm. There is high complexity in the design of stable current sources, with stray capacitance reducing the output impedance and bandwidth of the system. To confront this, we have designed an EIS current source which eliminates the effect of stray capacitance and other impacts of the capacitance via a variable inductance. In this paper, we present a combination of operational CCII based on a generalized impedance converter (OCCII-GIC) with a current source. The aim of this study is to use the EIS system as a biomedical imaging technique, which is effective in the early detection of breast cancer. This article begins with the theoretical description of the EIS structure, current source topologies and proposes a current conveyor in application of a Gyrator to eliminate the current source limitations and its development followed by simulation and experimental results. We demonstrated that the new design could achieve a high output impedance over a 3MHz frequency bandwidth when compared to other types of GIC circuits combined with an improved Howland topology.

  9. Large area CMOS image sensors

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; Guerrini, N.; Sedgwick, I.

    2011-01-01

    CMOS image sensors, also known as CMOS Active Pixel Sensors (APS) or Monolithic Active Pixel Sensors (MAPS), are today the dominant imaging devices. They are omnipresent in our daily life, as image sensors in cellular phones, web cams, digital cameras, ... In these applications, the pixels can be very small, in the micron range, and the sensors themselves tend to be limited in size. However, many scientific applications, like particle or X-ray detection, require large format, often with large pixels, as well as other specific performance, like low noise, radiation hardness or very fast readout. The sensors are also required to be sensitive to a broad spectrum of radiation: photons from the silicon cut-off in the IR down to UV and X- and gamma-rays through the visible spectrum as well as charged particles. This requirement calls for modifications to the substrate to be introduced to provide optimized sensitivity. This paper will review existing CMOS image sensors, whose size can be as large as a single CMOS wafer, and analyse the technical requirements and specific challenges of large format CMOS image sensors.

  10. Measurements of Si Hybrid CMOS X-Ray Detector Characteristics

    NASA Astrophysics Data System (ADS)

    Bongiorno, Stephen; Falcone, A.; Burrows, D.; Cook, R.

    2010-01-01

    The development of Hybrid CMOS Detectors (HCDs) for X-Ray telescope focal planes will place them in contention with CCDs on future satellite missions due to their faster frame rates, flexible readout scenarios, lower power consumption, and inherent radiation hardness. CCDs have been used with great success on the current generation of X-Ray telescopes (e.g. Chandra, XMM, Suzaku, and Swift). However their bucket-brigade readout architecture, which transfers charge across the chip with discrete component readout electronics, results in clockrate limited readout speeds that cause pileup (saturation) of bright sources and an inherent susceptibility to radiation induced displacement damage that limits mission lifetime. In contrast, HCDs read pixels with low power, on-chip multiplexer electronics in a random access fashion. Faster frame rates, achieved with multi-output readout design, will allow the next generation's larger effective area telescopes to observe bright sources free of pileup. Radiation damaged lattice sites effect a single pixel instead of an entire row. Random access, multi-output readout will allow for novel readout modes such as simultaneous bright-source-fast/whole-chip-slow readout. In order for HCDs to become useful X-Ray detectors, they must show noise and energy resolution performance similar to CCDs while retaining advantages inherent to HCDs. We will report on readnoise, conversion gain, and energy resolution measurements of X-Ray enhanced Teledyne HAWAII-1RG (H1RG) HCDs and describe techniques of H1RG data reduction.

  11. Measurements of Si hybrid CMOS x-ray detector characteristics

    NASA Astrophysics Data System (ADS)

    Bongiorno, Stephen D.; Falcone, Abe D.; Burrows, David N.; Cook, Robert; Bai, Yibin; Farris, Mark

    2009-08-01

    The development of Hybrid CMOS Detectors (HCDs) for X-Ray telescope focal planes will place them in contention with CCDs on future satellite missions due to their faster frame rates, flexible readout scenarios, lower power consumption, and inherent radiation hardness. CCDs have been used with great success on the current generation of X-Ray telescopes (e.g. Chandra, XMM, Suzaku, and Swift). However their bucket-brigade readout architecture, which transfers charge across the chip with discrete component readout electronics, results in clockrate limited readout speeds that cause pileup (saturation) of bright sources and an inherent susceptibility to radiation induced displacement damage that limits mission lifetime. In contrast, HCDs read pixels with low power, on-chip multiplexer electronics in a random access fashion. Faster frame rates achieved with multi-output readout design will allow the next generation's larger effective area telescopes to observe bright sources free of pileup. Radiation damaged lattice sites effect a single pixel instead of an entire row. Random access, multi-output readout will allow for novel readout modes such as simultaneous bright-source-fast/whole-chip-slow readout. In order for HCDs to be useful as X-Ray detectors, they must show noise and energy resolution performance similar to CCDs while retaining advantages inherent to HCDs. We will report on readnoise, conversion gain, and energy resolution measurements of an X-Ray enhanced Teledyne HAWAII-1RG (H1RG) HCD and describe techniques of H1RG data reduction.

  12. Black silicon enhanced photodetectors: a path to IR CMOS

    NASA Astrophysics Data System (ADS)

    Pralle, M. U.; Carey, J. E.; Homayoon, H.; Alie, S.; Sickler, J.; Li, X.; Jiang, J.; Miller, D.; Palsule, C.; McKee, J.

    2010-04-01

    SiOnyx has developed a novel silicon processing technology for CMOS sensors that will extend spectral sensitivity into the near/shortwave infrared (NIR/SWIR) and enable a full performance digital night vision capability comparable to that of current image-intensifier based night vision goggles. The process is compatible with established CMOS manufacturing infrastructure and has the promise of much lower cost than competing approaches. The measured thin layer quantum efficiency is as much as 10x that of incumbent imaging sensors with spectral sensitivity from 400 to 1200 nm.

  13. IR CMOS: ultrafast laser-enhanced silicon detection

    NASA Astrophysics Data System (ADS)

    Pralle, M. U.; Carey, J. E.; Homayoon, H.; Sickler, J.; Li, X.; Jiang, J.; Miller, D.; Palsule, C.; McKee, J.

    2011-06-01

    SiOnyx has developed a novel silicon processing technology for CMOS sensors that will extend spectral sensitivity into the near/shortwave infrared (NIR/SWIR) and enable a full performance digital night vision capability comparable to that of current image-intensifier based night vision goggles. The process is compatible with established CMOS manufacturing infrastructure and has the promise of much lower cost than competing approaches. The measured thin layer quantum efficiency is as much as 10x that of incumbent imaging sensors with spectral sensitivity from 400 to 1200 nm.

  14. Progress and future developments of high current ion source for neutral beam injector in the ASIPP

    NASA Astrophysics Data System (ADS)

    Hu, Chundong; Xie, Yahong; Xie, Yuanlai; Liu, Sheng; Liu, Zhimin; Xu, Yongjian; Liang, Lizhen; Sheng, Peng; Jiang, Caichao

    2015-04-01

    A high current hot cathode bucket ion source, which based on the US long pulse ion source is developed in Institute of Plasma Physics, Chinese Academy of Sciences. The ion source consists of a bucket plasma generator with multi-pole cusp fields and a set of tetrode accelerator with slit apertures. So far, four ion sources are developed and conditioned on the ion source test bed. 4 MW hydrogen beam with beam energy of 80 keV is extracted. In Aug. 2013, EAST NBI 1 with two ion source installed on the EAST, and achieved H-mode plasma with NBI injection for the first time. In order to achieve stable long pulse operation of high current ion source and negative ion source research, the RF ion source with 200 mm diameter and 120 mm depth driver is designed and developed. The first RF plasma generated with 2 kW power of 1 MHz frequency. More of the RF plasma tests and negative source relative research need to do in the future.

  15. Progress and future developments of high current ion source for neutral beam injector in the ASIPP

    SciTech Connect

    Hu, Chundong; Xie, Yahong Xie, Yuanlai; Liu, Sheng; Liu, Zhimin; Xu, Yongjian; Liang, Lizhen; Sheng, Peng; Jiang, Caichao

    2015-04-08

    A high current hot cathode bucket ion source, which based on the US long pulse ion source is developed in Institute of Plasma Physics, Chinese Academy of Sciences. The ion source consists of a bucket plasma generator with multi-pole cusp fields and a set of tetrode accelerator with slit apertures. So far, four ion sources are developed and conditioned on the ion source test bed. 4 MW hydrogen beam with beam energy of 80 keV is extracted. In Aug. 2013, EAST NBI 1 with two ion source installed on the EAST, and achieved H-mode plasma with NBI injection for the first time. In order to achieve stable long pulse operation of high current ion source and negative ion source research, the RF ion source with 200 mm diameter and 120 mm depth driver is designed and developed. The first RF plasma generated with 2 kW power of 1 MHz frequency. More of the RF plasma tests and negative source relative research need to do in the future.

  16. Spin current source based on a quantum point contact with local spin-orbit interaction

    SciTech Connect

    Nowak, M. P.; Szafran, B.

    2013-11-11

    Proposal for construction of a source of spin-polarized current based on quantum point contact (QPC) with local spin-orbit interaction is presented. We show that spin-orbit interaction present within the narrowing acts like a spin filter. The spin polarization of the current is discussed as a function of the Fermi energy and the width of the QPC.

  17. Radiation imaging with a new scintillator and a CMOS camera

    NASA Astrophysics Data System (ADS)

    Kurosawa, S.; Shoji, Y.; Pejchal, J.; Yokota, Y.; Yoshikawa, A.

    2014-07-01

    A new imaging system consisting of a high-sensitivity complementary metal-oxide semiconductor (CMOS) sensor, a microscope and a new scintillator, Ce-doped Gd3(Al,Ga)5O12 (Ce:GAGG) grown by the Czochralski process, has been developed. The noise, the dark current and the sensitivity of the CMOS camera (ORCA-Flash4.0, Hamamatsu) was revised and compared to a conventional CMOS, whose sensitivity is at the same level as that of a charge coupled device (CCD) camera. Without the scintillator, this system had a good position resolution of 2.1 ± 0.4 μm and we succeeded in obtaining the alpha-ray images using 1-mm thick Ce:GAGG crystal. This system can be applied for example to high energy X-ray beam profile monitor, etc.

  18. CMOS reliability issues for emerging cryogenic Lunar electronics applications

    NASA Astrophysics Data System (ADS)

    Chen, Tianbing; Zhu, Chendong; Najafizadeh, Laleh; Jun, Bongim; Ahmed, Adnan; Diestelhorst, Ryan; Espinel, Gustavo; Cressler, John D.

    2006-06-01

    We investigate the reliability issues associated with the application of CMOS devices contained within an advanced SiGe HBT BiCMOS technology to emerging cryogenic space electronics (e.g., down to 43 K, for Lunar missions). Reduced temperature operation improves CMOS device performance (e.g., transconductance, carrier mobility, subthreshold swing, and output current drive), as expected. However, operation at cryogenic temperatures also causes serious device reliability concerns, since it aggravates hot-carrier effects, effectively decreasing the inferred device lifetime significantly, especially at short gate lengths. In the paper, hot-carrier effects are demonstrated to be a stronger function of the device gate length than the temperature, suggesting that significant trade-offs between the gate length and the operational temperature must be made in order to ensure safe and reliable operation over typical projected mission lifetimes in these hostile environments.

  19. Operation and biasing for single device equivalent to CMOS

    DOEpatents

    Welch, James D.

    2001-01-01

    Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of field induced carriers. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents. Operation of the gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems under typical bias schemes is described, and simple demonstrative five mask fabrication procedures for the inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems are also presented.

  20. Metrology Of Silicide Contacts For Future CMOS

    NASA Astrophysics Data System (ADS)

    Zollner, Stefan; Gregory, Richard B.; Kottke, M. L.; Vartanian, Victor; Wang, Xiang-Dong; Theodore, David; Fejes, P. L.; Conner, J. R.; Raymond, Mark; Zhu, Xiaoyan; Denning, Dean; Bolton, Scott; Chang, Kyuhwan; Noble, Ross; Jahanbani, Mohamad; Rossow, Marc; Goedeke, Darren; Filipiak, Stan; Garcia, Ricardo; Jawarani, Dharmesh; Taylor, Bill; Nguyen, Bich-Yen; Crabtree, P. E.; Thean, Aaron

    2007-09-01

    Silicide materials (NiSi, CoSi2, TiSi2, etc) are used to form low-resistance contacts between the back-end (W plugs and Cu interconnects) and front-end portions (silicon source, drain, and gate regions) of integrated CMOS circuits. At the 65 nm node, a transition from CoSi2 to NiSi was necessary because of the unique capability of NiSi to form narrow silicide nanowires on active (monocrystalline) and gate (polycrystalline) lines. Like its predecessors TiSi2 and CoSi2, NiSi is a mid-gap silicide, i.e., the Fermi level of the NiSi metal is pinned half-way between the conduction and valence band edges in silicon. This leads to a Schottky barrier between the silicide and silicon source-drain regions, which creates undesirable parasitic resistances. For future CMOS generations, band-edge silicides, such as PtSi for contacts to p-type or rare earth silicides for contacts to n-type Si will be needed. This paper reviews metrology and characterization techniques for NiSi process control for development and manufacturing, with special emphasis on x-ray reflectance and x-ray fluorescence. We also report measurement methods useful for development of a PtSi PMOS module.

  1. Generalized theory for current-source-density analysis in brain tissue

    NASA Astrophysics Data System (ADS)

    Bédard, Claude; Destexhe, Alain

    2011-10-01

    The current-source density (CSD) analysis is a widely used method in brain electrophysiology, but this method rests on a series of assumptions, namely that the surrounding extracellular medium is resistive and uniform, and in some versions of the theory, that the current sources are exclusively made by dipoles. Because of these assumptions, this standard model does not correctly describe the contributions of monopolar sources or of nonresistive aspects of the extracellular medium. We propose here a general framework to model electric fields and potentials resulting from current source densities, without relying on the above assumptions. We develop a mean-field formalism that is a generalization of the standard model and that can directly incorporate nonresistive (nonohmic) properties of the extracellular medium, such as ionic diffusion effects. This formalism recovers the classic results of the standard model such as the CSD analysis, but in addition, we provide expressions to generalize the CSD approach to situations with nonresistive media and arbitrarily complex multipolar configurations of current sources. We found that the power spectrum of the signal contains the signature of the nature of current sources and extracellular medium, which provides a direct way to estimate those properties from experimental data and, in particular, estimate the possible contribution of electric monopoles.

  2. A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Daniels, Taumi S.

    1990-01-01

    The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

  3. Current knowledge of US metal and nonmetal miner health: Current and potential data sources for analysis of miner health status

    PubMed Central

    Yeoman, K. M.; Halldin, C. N.; Wood, J.; Storey, E.; Johns, D.; Laney, A. S.

    2016-01-01

    ABSTRACT Little is known about the current health status of US metal and nonmetal (MNM) miners, in part because no health surveillance systems exist for this population. The National Institute for Occupational Safety and Health (NIOSH) is developing a program to characterize burden of disease among MNM miners. This report discusses current knowledge and potential data sources of MNM miner health. Recent national surveys were analyzed, and literature specific to MNM miner health status was reviewed. No robust estimates of disease prevalence were identified, and national surveys did not provide information specific to MNM miners. Because substantial gaps exist in the understanding of MNM miners' current health status, NIOSH plans to develop a health surveillance program for this population to guide intervention efforts to reduce occupational and personal risks for chronic illness. PMID:25658684

  4. A low noise modular current source for stable magnetic field control

    NASA Astrophysics Data System (ADS)

    Biancalana, Valerio; Bevilacqua, Giuseppe; Chessa, Piero; Dancheva, Yordanka; Cecchi, Roberto; Stiaccini, Leonardo

    2017-03-01

    A low cost, stable, programmable, unipolar current source is described. The circuit is designed in view of a modular arrangement, suitable for applications where several DC sources must be controlled at once. A hybrid switching/linear design helps in improving the stability and in reducing the power dissipation and cross-talking. Multiple units can be supplied by a single DC power supply, while allowing for a variety of maximal current values and compliance voltages at the outputs. The circuit is analogically controlled by a unipolar voltage, enabling current programmability and control through commercial digital-to-analogue conversion cards.

  5. Optimization of negative ion current in a compact microwave driven upper hybrid resonance multicusp plasma source.

    PubMed

    Sahu, D; Bhattacharjee, S; Singh, M J; Bandyopadhyay, M; Chakraborty, A

    2012-02-01

    Performance of a microwave driven upper hybrid resonance multicusp plasma source as a volume negative ion source is reported. Microwaves are directly launched into the plasma chamber predominantly in the TE(11) mode. The source is operated at different discharge conditions to obtain the optimized negative H(-) ion current which is ∼33 μA (0.26 mA∕cm(2)). Particle balance equations are solved to estimate the negative ion density, which is compared with the experimental results. Future prospects of the source are discussed.

  6. MonoColor CMOS sensor

    NASA Astrophysics Data System (ADS)

    Wang, Ynjiun P.

    2009-02-01

    A new breed of CMOS color sensor called MonoColor sensor is developed for a barcode reading application in AIDC industry. The RGBW color filter array (CFA) in a MonoColor sensor is arranged in a 8 x 8 pixels CFA with only 4 pixels of them are color (RGB) pixels and the rest of 60 pixels are transparent or monochrome. Since the majority of pixels are monochrome, MonoColor sensor maintains 98% barcode decode performance compared with a pure monochrome CMOS sensor. With the help of monochrome and color pixel fusion technique, the resulting color pictures have similar color quality in terms of Color Semantic Error (CSE) compared with a Bayer pattern (RGB) CMOS color camera. Since monochrome pixels are more sensitive than color pixels, a MonoColor sensor produces in general about 2X brighter color picture and higher luminance pixel resolution.

  7. A CMOS floating point multiplier

    NASA Astrophysics Data System (ADS)

    Uya, M.; Kaneko, K.; Yasui, J.

    1984-10-01

    This paper describes a 32-bit CMOS floating point multiplier. The chip can perform 32-bit floating point multiplication (based on the proposed IEEE Standard format) and 24-bit fixed point multiplication (two's complement format) in less than 78.7 and 71.1 ns, respectively, and the typical power dissipation is 195 mW at 10 million operations per second. High-speed multiplication techniques - a modified Booth's allgorithm, a carry save adder scheme, a high-speed CMOS full adder, and a modified carry select adder - are used to achieve the above high performance. The chip is designed for compatibility with 16-bit microcomputer systems, and is fabricated in 2 micron n-well CMOS technology; it contains about 23000 transistors of 5.75 x 5.67 sq mm in size.

  8. Repetitive Adjustment to Estimate the Electric Current Sources in a Nerve Fiber with Magnetic Field Measurement

    NASA Astrophysics Data System (ADS)

    Hayami, Takehito; Mishima, Yukuo; Hiwaki, Osamu

    Magnetic field measuring equipment provides us the way to examine the active position of a peripheral nerve without contact or invasion. To develop a process to estimate the position precisely, simulation study of the magnetic field induced by a myelinated nerve fiber was executed. The electric current sources around the active position of a nerve fiber can be approximated as a pair of electric current dipoles, which represent depolarization and repolarization respectively. Therefore the current sources to estimate from the detected pattern of the magnetic field were modeled as a pair of electric current dipoles. A repetitive adjustment process was proposed as an effective method to find the appropriate positions of the dipoles as the sources of the magnetic fields.

  9. Activation processes on GaAs photocathode by different currents of oxygen source

    NASA Astrophysics Data System (ADS)

    Miao, Zhuang; Shi, Feng; Cheng, Hongchang; Wang, Shufei; Zhang, Xiaohui; Yuan, Yuan; Chen, Chang

    2015-04-01

    In order to know the influence of activation processes on GaAs photocathodes, three GaAs samples were activated by a fixed current of cesium source and different currents of oxygen source. The current of caesium source is same during activation to ensure initial adsorption of caesium quantum is similar, which is the base to show the difference during alternation activation of caesium and oxygen. Analysed with the activation data, it is indicated that Cs-to-O current ratio of 1.07 is the optimum ratio to obtain higher sensitivity and better stability. According to double dipole model, stable and uniform double dipole layers of GaAs-O-Cs:Cs-O-Cs are formed and negative electron affinity is achieved on GaAs surface by activation with cesium and oxygen. The analytical result is just coincident with the model. Thus there is an efficient technological method to improve sensitivity and stability of GaAs photocathode.

  10. Introduction of performance boosters like Ge as channel material for the future of CMOS

    SciTech Connect

    Samia, Slimani; Bouaza, Djellouli

    2016-06-10

    High mobility materials are being considered to replace Si in the channel to achieve higher drive currents and switching speeds. Ge is one of new attractive channel materials that require CMOS scaling For future technology nodes and future high performance P-MOSFETS, we have studied a nanoscale SOI DG MOSFETs using quantum simulation approach on DG MOSFETs within the variation of Ge channel concentration and in the presence of source and drain doping by replacing Silicon in the channel by Ge using various dielectric constant. The use of high mobility channel (like Ge) to maximize the MOSFET IDsat and simultaneously circumvent the poor electrostatic control to suppress short-channel effects and enhance source injection velocity. The leakage current (I{sub off}) can be controlled by different gates oxide thickness more ever the required threshold voltage (V{sub TH}) can be achieved by keeping gate work function and altering the doping channel.

  11. Representation of bioelectric current sources using Whitney elements in the finite element method

    NASA Astrophysics Data System (ADS)

    Oguz Tanzer, I.; Järvenpää, Seppo; Nenonen, Jukka; Somersalo, Erkki

    2005-07-01

    Bioelectric current sources of magneto- and electroencephalograms (MEG, EEG) are usually modelled with discrete delta-function type current dipoles, despite the fact that the currents in the brain are naturally continuous throughout the neuronal tissue. In this study, we represent bioelectric current sources in terms of Whitney-type elements in the finite element method (FEM) using a tetrahedral mesh. The aim is to study how well the Whitney elements can reproduce the potential and magnetic field patterns generated by a point current dipole in a homogeneous conducting sphere. The electric potential is solved for a unit sphere model with isotropic conductivity and magnetic fields are calculated for points located on a cap outside the sphere. The computed potential and magnetic field are compared with analytical solutions for a current dipole. Relative difference measures between the FEM and analytical solutions are less than 1%, suggesting that Whitney elements as bioelectric current sources are able to produce the same potential and magnetic field patterns as the point dipole sources.

  12. The differential Howland current source with high signal to noise ratio for bioimpedance measurement system

    SciTech Connect

    Liu, Jinzhen; Li, Gang; Lin, Ling; Qiao, Xiaoyan; Wang, Mengjun; Zhang, Weibo

    2014-05-15

    The stability and signal to noise ratio (SNR) of the current source circuit are the important factors contributing to enhance the accuracy and sensitivity in bioimpedance measurement system. In this paper we propose a new differential Howland topology current source and evaluate its output characters by simulation and actual measurement. The results include (1) the output current and impedance in high frequencies are stabilized after compensation methods. And the stability of output current in the differential current source circuit (DCSC) is 0.2%. (2) The output impedance of two current circuits below the frequency of 200 KHz is above 1 MΩ, and below 1 MHz the output impedance can arrive to 200 KΩ. Then in total the output impedance of the DCSC is higher than that of the Howland current source circuit (HCSC). (3) The SNR of the DCSC are 85.64 dB and 65 dB in the simulation and actual measurement with 10 KHz, which illustrates that the DCSC effectively eliminates the common mode interference. (4) The maximum load in the DCSC is twice as much as that of the HCSC. Lastly a two-dimensional phantom electrical impedance tomography is well reconstructed with the proposed HCSC. Therefore, the measured performance shows that the DCSC can significantly improve the output impedance, the stability, the maximum load, and the SNR of the measurement system.

  13. Representation of bioelectric current sources using Whitney elements in the finite element method.

    PubMed

    Tanzer, I Oğuz; Järvenpää, Seppo; Nenonen, Jukka; Somersalo, Erkki

    2005-07-07

    Bioelectric current sources of magneto- and electroencephalograms (MEG, EEG) are usually modelled with discrete delta-function type current dipoles, despite the fact that the currents in the brain are naturally continuous throughout the neuronal tissue. In this study, we represent bioelectric current sources in terms of Whitney-type elements in the finite element method (FEM) using a tetrahedral mesh. The aim is to study how well the Whitney elements can reproduce the potential and magnetic field patterns generated by a point current dipole in a homogeneous conducting sphere. The electric potential is solved for a unit sphere model with isotropic conductivity and magnetic fields are calculated for points located on a cap outside the sphere. The computed potential and magnetic field are compared with analytical solutions for a current dipole. Relative difference measures between the FEM and analytical solutions are less than 1%, suggesting that Whitney elements as bioelectric current sources are able to produce the same potential and magnetic field patterns as the point dipole sources.

  14. CMOS Integrated Carbon Nanotube Sensor

    SciTech Connect

    Perez, M. S.; Lerner, B.; Boselli, A.; Lamagna, A.; Obregon, P. D. Pareja; Julian, P. M.; Mandolesi, P. S.; Buffa, F. A.

    2009-05-23

    Recently carbon nanotubes (CNTs) have been gaining their importance as sensors for gases, temperature and chemicals. Advances in fabrication processes simplify the formation of CNT sensor on silicon substrate. We have integrated single wall carbon nanotubes (SWCNTs) with complementary metal oxide semiconductor process (CMOS) to produce a chip sensor system. The sensor prototype was designed and fabricated using a 0.30 um CMOS process. The main advantage is that the device has a voltage amplifier so the electrical measure can be taken and amplified inside the sensor. When the conductance of the SWCNTs varies in response to media changes, this is observed as a variation in the output tension accordingly.

  15. Monolithic CMOS imaging x-ray spectrometers

    NASA Astrophysics Data System (ADS)

    Kenter, Almus; Kraft, Ralph; Gauron, Thomas; Murray, Stephen S.

    2014-07-01

    The Smithsonian Astrophysical Observatory (SAO) in collaboration with SRI/Sarnoff is developing monolithic CMOS detectors optimized for x-ray astronomy. The goal of this multi-year program is to produce CMOS x-ray imaging spectrometers that are Fano noise limited over the 0.1-10keV energy band while incorporating the many benefits of CMOS technology. These benefits include: low power consumption, radiation "hardness", high levels of integration, and very high read rates. Small format test devices from a previous wafer fabrication run (2011-2012) have recently been back-thinned and tested for response below 1keV. These devices perform as expected in regards to dark current, read noise, spectral response and Quantum Efficiency (QE). We demonstrate that running these devices at rates ~> 1Mpix/second eliminates the need for cooling as shot noise from any dark current is greatly mitigated. The test devices were fabricated on 15μm, high resistivity custom (~30kΩ-cm) epitaxial silicon and have a 16 by 192 pixel format. They incorporate 16μm pitch, 6 Transistor Pinned Photo Diode (6TPPD) pixels which have ~40μV/electron sensitivity and a highly parallel analog CDS signal chain. Newer, improved, lower noise detectors have just been fabricated (October 2013). These new detectors are fabricated on 9μm epitaxial silicon and have a 1k by 1k format. They incorporate similar 16μm pitch, 6TPPD pixels but have ~ 50% higher sensitivity and much (3×) lower read noise. These new detectors have undergone preliminary testing for functionality in Front Illuminated (FI) form and are presently being prepared for back thinning and packaging. Monolithic CMOS devices such as these, would be ideal candidate detectors for the focal planes of Solar, planetary and other space-borne x-ray astronomy missions. The high through-put, low noise and excellent low energy response, provide high dynamic range and good time resolution; bright, time varying x-ray features could be temporally and

  16. Lp-Norm Regularization in Volumetric Imaging of Cardiac Current Sources

    PubMed Central

    Rahimi, Azar; Xu, Jingjia; Wang, Linwei

    2013-01-01

    Advances in computer vision have substantially improved our ability to analyze the structure and mechanics of the heart. In comparison, our ability to observe and analyze cardiac electrical activities is much limited. The progress to computationally reconstruct cardiac current sources from noninvasive voltage data sensed on the body surface has been hindered by the ill-posedness and the lack of a unique solution of the reconstruction problem. Common L2- and L1-norm regularizations tend to produce a solution that is either too diffused or too scattered to reflect the complex spatial structure of current source distribution in the heart. In this work, we propose a general regularization with Lp-norm (1 < p < 2) constraint to bridge the gap and balance between an overly smeared and overly focal solution in cardiac source reconstruction. In a set of phantom experiments, we demonstrate the superiority of the proposed Lp-norm method over its L1 and L2 counterparts in imaging cardiac current sources with increasing extents. Through computer-simulated and real-data experiments, we further demonstrate the feasibility of the proposed method in imaging the complex structure of excitation wavefront, as well as current sources distributed along the postinfarction scar border. This ability to preserve the spatial structure of source distribution is important for revealing the potential disruption to the normal heart excitation. PMID:24348735

  17. Conical Current Sheets in a Source-Surface Model of the Heliosphere

    NASA Astrophysics Data System (ADS)

    Schulz, M.

    2007-12-01

    Different methods of modeling the coronal and heliospheric magnetic field are conveniently visualized and intercompared by applying them to ideally axisymmetric field models. Thus, for example, a dipolar B field with its moment parallel to the Sun's rotation axis leads to a flat heliospheric current sheet. More general solar B fields (still axisymmetric about the solar rotation axis for simplicity) typically lead to cone-shaped current sheets beyond the source surface (and presumably also in MHD models). As in the dipolar case [Schulz et al., Solar Phys., 60, 83-104, 1978], such conical current sheets can be made realistically thin by taking the source surface to be non-spherical in a way that reflects the underlying structure of the Sun's main B field. A source surface that seems to work well in this respect [Schulz, Ann. Geophysicae, 15, 1379-1387, 1997] is a surface of constant F = (1/r)kB, where B is the scalar strength of the Sun's main magnetic field and k (~ 1.4) is a shape parameter. This construction tends to flatten the source surface in regions where B is relatively weak. Thus, for example, the source surface for a dipolar B field is shaped somewhat like a Rugby football, whereas the source surface for an axisymmetric quadrupolar B field is similarly elongated but somewhat flattened (as if stuffed into a cone) at mid-latitudes. A linear combination of co-axial dipolar and quadrupolar B fields generates a somewhat pear-shaped (but still convex) source surface. If the region surrounded by the source surface is regarded as current-free, then the source surface itself should be (as nearly as possible) an equipotential surface for the corresponding magnetic scalar potential (expanded, for example, in spherical harmonics). The solar wind should then flow not quite radially, but rather in a straight line along the outward normal to the source surface, and the heliospheric B field should follow a corresponding generalization of Parker's spiral [Levine et al

  18. Dynamical changes of ion current distribution for a Penning discharge source using a Langmuir probe arraya)

    NASA Astrophysics Data System (ADS)

    Li, M.; Xiang, W.; Xiao, K. X.; Chen, L.

    2012-02-01

    A paralleled plate electrode and a 9-tip Langmuir probe array located 1 mm behind the extraction exit of a cold cathode Penning ion source are employed to measure the total current and the dynamical changes of the ion current in the 2D profile, respectively. Operation of the ion source by 500 V DC power supply, the paralleled plate electrode and the Langmuir probe array are driven by a bias voltage ranging from -200 V to 200 V. The dependence of the total current and the dynamical changes of the ion current in the 2D profile are presented at the different bias voltage. The experimental results show that the distribution of ion current is axial symmetry and approximate a unimodal distribution.

  19. Changes in EEG current sources induced by neurofeedback in learning disabled children. An exploratory study.

    PubMed

    Fernández, Thalía; Harmony, Thalía; Fernández-Bouzas, Antonio; Díaz-Comas, Lourdes; Prado-Alcalá, Roberto A; Valdés-Sosa, Pedro; Otero, Gloria; Bosch, Jorge; Galán, Lídice; Santiago-Rodríguez, Efraín; Aubert, Eduardo; García-Martínez, Fabiola

    2007-12-01

    The objective of this work was to explore Neurofeedback (NFB) effects on EEG current sources in Learning Disabled (LD) children, and to corroborate its beneficial consequences on behavioral and cognitive performance. NFB was given in twenty 30-min sessions to 11 LD children to reduce their abnormally high theta/alpha ratios (Experimental Group). Another five LD children with the same characteristics received a placebo treatment (Control Group). In the Control Group no changes in behavior or EEG current source were observed. In the Experimental Group, immediately after treatment children showed behavioral and cognitive improvements, but current source analysis showed few modifications; however, 2 months after treatment many changes occurred: a decrease in current of frequencies within the theta band, mainly in left frontal and cingulate regions, and enhancement in current of frequencies within the alpha band, principally in the right temporal lobe and right frontal regions, and of frequencies within the beta band, mainly in left temporal, right frontal and cingulate cortex regions. In conclusion, NFB is a possibly efficacious treatment for LD children with an abnormally high theta/alpha ratio in any lead. The changes observed in EEG current sources may reflect the neurophysiological bases of the improvement that children experienced in their behavioral and cognitive activities.

  20. Temperature dependence of the current in Schottky-barrier source-gated transistors

    NASA Astrophysics Data System (ADS)

    Sporea, R. A.; Overy, M.; Shannon, J. M.; Silva, S. R. P.

    2015-05-01

    The temperature dependence of the drain current is an important parameter in thin-film transistors. In this paper, we propose that in source-gated transistors (SGTs), this temperature dependence can be controlled and tuned by varying the length of the source electrode. SGTs comprise a reverse biased potential barrier at the source which controls the current. As a result, a large activation energy for the drain current may be present which, although useful in specific temperature sensing applications, is in general deleterious in many circuit functions. With support from numerical simulations with Silvaco Atlas, we describe how increasing the length of the source electrode can be used to reduce the activation energy of SGT drain current, while maintaining the defining characteristics of SGTs: low saturation voltage, high output impedance in saturation, and tolerance to geometry variations. In this study, we apply the dual current injection modes to obtain drain currents with high and low activation energies and propose mechanisms for their exploitation in future large-area integrated circuit designs.

  1. Source tracking fecal bacteria in water: a critical review of current methods.

    PubMed

    Meays, Cynthia L; Broersma, Klaas; Nordin, Rick; Mazumder, Asit

    2004-10-01

    Many molecular and biochemical methods and techniques are being developed to track sources of bacteria in water and food. Currently, there is no standard method proposed for source tracking. This manuscript is a critical evaluation of the various methods used in watersheds, and highlights some of the advantages and disadvantages of each method. Making a decision on a single or combination of methods to use under a particular situation will depend on a number of factors including: question(s) to be answered, scale of identification (broad scale versus specific species identification), available expertise, cost of analysis, turnaround time, and access to facilities. This manuscript reviews several source tracking methodologies which are in current use for source tracking fecal bacteria in the environment including: ribotyping, pulse-field gel electrophoresis, denaturing-gradient gel electrophoresis, repetitive DNA sequences (Rep-PCR), host-specific 16S rDNA genetic markers, and antibiotic resistance analysis.

  2. Current source imaging for high spatial resolution magnetocardiography in normal and abnormal rat cardiac muscles

    NASA Astrophysics Data System (ADS)

    Uchida, S.; Iramina, K.; Goto, K.; Ueno, S.

    2000-05-01

    The purpose of our study was to identify the current source produced by acute ischemia and infarction. We measured magnetocardiograms (MCG) and electrocardiograms (ECG) of five male rats using a high-resolution dc superconducting quantum interference device gradiometer in a magnetically shielded room after performing coronary artery occlusion. The spatial resolution of the detecting magnetic field of our system is higher than the typical system, thus permitting the measurement of magnetic fields in small animals. Distribution of the magnetic fields B(t) and distribution of |rot B(t)|, which corresponded to the distribution of the current source, were imaged by 12-channel MCGs. As a result, the distribution of current source changes in the affected area of the myocardium during the ST segment, and amplitude of the peak significantly increased after occlusion. Our system can be used to help clarify the mechanism of the ST shift related to severe heart disease.

  3. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    SciTech Connect

    Roychowdhury, P. Mishra, L.; Kewlani, H.; Mittal, K. C.; Patil, D. S.

    2014-03-15

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20–40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, −2 to −4 kV, and 0 kV, respectively. The total ion beam current of 30–40 mA is recorded on Faraday cup at 40 keV of beam energy at 600–1000 W of microwave power, 800–1000 G axial magnetic field and (1.2–3.9) × 10{sup −3} mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  4. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    NASA Astrophysics Data System (ADS)

    Roychowdhury, P.; Mishra, L.; Kewlani, H.; Patil, D. S.; Mittal, K. C.

    2014-03-01

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20-40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, -2 to -4 kV, and 0 kV, respectively. The total ion beam current of 30-40 mA is recorded on Faraday cup at 40 keV of beam energy at 600-1000 W of microwave power, 800-1000 G axial magnetic field and (1.2-3.9) × 10-3 mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  5. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source.

    PubMed

    Roychowdhury, P; Mishra, L; Kewlani, H; Patil, D S; Mittal, K C

    2014-03-01

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20-40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, -2 to -4 kV, and 0 kV, respectively. The total ion beam current of 30-40 mA is recorded on Faraday cup at 40 keV of beam energy at 600-1000 W of microwave power, 800-1000 G axial magnetic field and (1.2-3.9) × 10(-3) mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  6. A comparison of photon counting and current measuring techniques in spectrophotometry of faint sources.

    PubMed

    Tull, R G

    1968-10-01

    The component of dark noise produced by Cerenkov pulses in photomultipliers due to cosmic ray mu mesons is discussed. It is shown by integration of pulse height spectra that this source of noise can be the limiting factor in de measuring spectrophotometry of faint astronomical sources. Direct current methods of photometry are compared with photon counting, and the advantage of photon counting is demonstrated under various operating conditions.

  7. Modulated CMOS camera for fluorescence lifetime microscopy.

    PubMed

    Chen, Hongtao; Holst, Gerhard; Gratton, Enrico

    2015-12-01

    Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) is a fast and accurate method to measure the fluorescence lifetime of entire images. However, the complexity and high costs involved in construction of such a system limit the extensive use of this technique. PCO AG recently released the first luminescence lifetime imaging camera based on a high frequency modulated CMOS image sensor, QMFLIM2. Here we tested and provide operational procedures to calibrate the camera and to improve the accuracy using corrections necessary for image analysis. With its flexible input/output options, we are able to use a modulated laser diode or a 20 MHz pulsed white supercontinuum laser as the light source. The output of the camera consists of a stack of modulated images that can be analyzed by the SimFCS software using the phasor approach. The nonuniform system response across the image sensor must be calibrated at the pixel level. This pixel calibration is crucial and needed for every camera settings, e.g. modulation frequency and exposure time. A significant dependency of the modulation signal on the intensity was also observed and hence an additional calibration is needed for each pixel depending on the pixel intensity level. These corrections are important not only for the fundamental frequency, but also for the higher harmonics when using the pulsed supercontinuum laser. With these post data acquisition corrections, the PCO CMOS-FLIM camera can be used for various biomedical applications requiring a large frame and high speed acquisition.

  8. Challenges of nickel silicidation in CMOS technologies

    SciTech Connect

    Breil, Nicolas; Lavoie, Christian; Ozcan, Ahmet; Baumann, Frieder; Klymko, Nancy; Nummy, Karen; Sun, Bing; Jordan-Sweet, Jean; Yu, Jian; Zhu, Frank; Narasimha, Shreesh; Chudzik, Michael

    2015-04-01

    In our paper, we review some of the key challenges associated with the Ni silicidation process in the most recent CMOS technologies. The introduction of new materials (e.g.SiGe), and of non-planar architectures bring some important changes that require fundamental investigation from a material engineering perspective. Following a discussion of the device architecture and silicide evolution through the last CMOS generations, we focus our study on a very peculiar defect, termed NiSi-Fangs. We describe a mechanism for the defect formation, and present a detailed material analysis that supports this mechanism. We highlight some of the possible metal enrichment processes of the nickel monosilicide such as oxidation or various RIE (Reactive Ion Etching) plasma process, leading to a metal source available for defect formation. Furthermore, we investigate the NiSi formation and re-formation silicidation differences between Si and SiGe materials, and between (1 0 0) and (1 1 1) orientations. Finally, we show that the thermal budgets post silicidation can lead to the formation of NiSi-Fangs if the structure and the processes are not optimized. Beyond the understanding of the defect and the discussion on the engineering solutions used to prevent its formation, the interest of this investigation also lies in the fundamental learning within the Ni–Pt–Si–Ge system and some additional perspective on Ni-based contacts to advanced microelectronic devices.

  9. Reliability in CMOS IC processing

    NASA Technical Reports Server (NTRS)

    Shreeve, R.; Ferrier, S.; Hall, D.; Wang, J.

    1990-01-01

    Critical CMOS IC processing reliability monitors are defined in this paper. These monitors are divided into three categories: process qualifications, ongoing production workcell monitors, and ongoing reliability monitors. The key measures in each of these categories are identified and prioritized based on their importance.

  10. Development of CMOS integrated circuits

    NASA Technical Reports Server (NTRS)

    Bertino, F.; Feller, A.; Greenhouse, J.; Lombardi, T.; Merriam, A.; Noto, R.; Ozga, S.; Pryor, R.; Ramondetta, P.; Smith, A.

    1979-01-01

    Report documents life cycles of two custom CMOS integrated circuits: (1) 4-bit multiplexed register with shift left and shift right capabilities, and (2) dual 4-bit registers. Cycles described include conception as logic diagrams through design, fabrication, testing, and delivery.

  11. Current State of Research of Alternate Fuel Sources for Passenger Vehicles

    NASA Astrophysics Data System (ADS)

    Massey, Lee

    2008-03-01

    The purpose of this project is to report on the current state of research in the field of alternate fuel sources for passenger vehicles. Because the number of alternate fuel options is very large, this study focuses on selected bio-fuels and briefly describes a couple of the most popular non-bio and non-renewable alternatives. The fuel and energy sources studied are compared using well-to-wheel and well-to-tank net energy balances. Data also includes relative production capabilities by volume in terms of current fossil fuels. Qualitative data includes production methods and transportability.

  12. Note: Temperature effects in the modified Howland current source for electrical bioimpedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Fernandez Santos, S.; Bertemes-Filho, P.

    2017-07-01

    The aim of this study is to show how the modified Howland current source (MHCS) is affected by temperature changes. The source has been tested in a temperature range from 20 to 70 °C and frequency range from 100 Hz to 1 MHz. Parameters like output current, output impedance, total harmonic distortion, and oscillation have been measured. The measurements were made inside a temperature controlled environment. It was showed that the MHCS is stable at temperatures below 70 °C. Operational amplifiers with a low temperature drift and matching resistor should be carefully considered in order to prevent oscillations at high temperatures.

  13. Optimisation of add-on NPN Transistor for a CMOS Process

    NASA Astrophysics Data System (ADS)

    Aurola, Artto; Ronkainen, Hannu; Mellin, Joni

    2004-01-01

    The objective of this research was to add an npn-bipolar transistor for a CMOS process. This was to be done with minimal additional process steps and without changing any existing CMOS parameters. The minimum line width of the process was 1.2µm, the wafers were p-type and 100mm in diameter and no epitaxial or polysilicon layers were used. To minimise the additional process steps a triple diffused transistor was selected as the basis of the research. The emitter was formed from a diffusion contacting NMOSFET source and drain to aluminium. As collector diffusion two approaches were investigated the pnpbipolar transistors isolation nwell and the PMOSFET n-well. The only additional step to the CMOS process due to the npn-transistor fabrication resulted from the formation of base diffusion. The specifications for the npn-transistor were 80 for the current gain, 100V for the early voltage and 60MHz for the transition frequency at 1µA collector current. Four different transistor structures were investigated two octagonal transistors having either emitter or base in the centre and two minimum area rectangular transistors having either base or emitter in the middle. The octagonal transistor having the emitter in the centre was chosen as the basis of simulations. It was first simulated with a device simulator. Next combined process and device simulations were done. Based on simulation results different processes were tested on wafers. Only the octagonal transistor having the emitter in the middle satisfied the specifications when a pnp isolation n-well was used as a collector.

  14. Current status and future perspectives of accelerator-based x-ray light sources

    NASA Astrophysics Data System (ADS)

    Tanaka, Takashi

    2017-09-01

    State-of-the-art x-ray light sources are nowadays based on large-scale electron accelerators, because the synchrotron radiation (SR) and x-ray free electron laser (XFEL) radiation generated by high-energy electron beams have many advantages over other alternatives in terms of the wavelength tunability, high brightness and flux, high coherence, flexible polarization states, and so on. This is the reason why SR and XFEL light sources have largely contributed to the evolution of x-ray science. This paper reviews the current status of such accelerator-based x-ray light source facilities and discusses their future perspectives.

  15. Spatial Localization of Sources in the Rat Subthalamic Motor Region Using an Inverse Current Source Density Method

    PubMed Central

    van Dijk, Kees J.; Janssen, Marcus L. F.; Zwartjes, Daphne G. M.; Temel, Yasin; Visser-Vandewalle, Veerle; Veltink, Peter H.; Benazzouz, Abdelhamid; Heida, Tjitske

    2016-01-01

    Objective: In this study we introduce the use of the current source density (CSD) method as a way to visualize the spatial organization of evoked responses in the rat subthalamic nucleus (STN) at fixed time stamps resulting from motor cortex stimulation. This method offers opportunities to visualize neuronal input and study the relation between the synaptic input and the neural output of neural populations. Approach: Motor cortex evoked local field potentials and unit activity were measured in the subthalamic region, with a 3D measurement grid consisting of 320 measurement points and high spatial resolution. This allowed us to visualize the evoked synaptic input by estimating the current source density (CSD) from the measured local field potentials, using the inverse CSD method. At the same time, the neuronal output of the cells within the grid is assessed by calculating post stimulus time histograms. Main results: The CSD method resulted in clear and distinguishable sources and sinks of the neuronal input activity in the STN after motor cortex stimulation. We showed that the center of the synaptic input of the STN from the motor cortex is located dorsal to the input from globus pallidus. Significance: For the first time we have performed CSD analysis on motor cortex stimulation evoked LFP responses in the rat STN as a proof of principle. Our results suggest that the CSD method can be used to gain new insights into the spatial extent of synaptic pathways in brain structures. PMID:27857684

  16. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control

    SciTech Connect

    Cochems, P.; Kirk, A. T.; Bunert, E.; Runge, M.; Goncalves, P.; Zimmermann, S.

    2015-06-15

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  17. Ionospheric current source modeling and global geomagnetic induction using ground geomagnetic observatory data

    NASA Astrophysics Data System (ADS)

    Sun, J.; Kelbert, A.; Egbert, G. D.

    2015-10-01

    Long-period global-scale electromagnetic induction studies of deep Earth conductivity are based almost exclusively on magnetovariational methods and require accurate models of external source spatial structure. We describe approaches to inverting for both the external sources and three-dimensional (3-D) conductivity variations and apply these methods to long-period (T≥1.2 days) geomagnetic observatory data. Our scheme involves three steps: (1) Observatory data from 60 years (only partly overlapping and with many large gaps) are reduced and merged into dominant spatial modes using a scheme based on frequency domain principal components. (2) Resulting modes are inverted for corresponding external source spatial structure, using a simplified conductivity model with radial variations overlain by a two-dimensional thin sheet. The source inversion is regularized using a physically based source covariance, generated through superposition of correlated tilted zonal (quasi-dipole) current loops, representing ionospheric source complexity smoothed by Earth rotation. Free parameters in the source covariance model are tuned by a leave-one-out cross-validation scheme. (3) The estimated data modes are inverted for 3-D Earth conductivity, assuming the source excitation estimated in step 2. Together, these developments constitute key components in a practical scheme for simultaneous inversion of the catalogue of historical and modern observatory data for external source spatial structure and 3-D Earth conductivity.

  18. Ionospheric current source modeling and global geomagnetic induction using ground geomagnetic observatory data

    USGS Publications Warehouse

    Sung, Joyce; Kelbert, Anna; Egbert, G.D.

    2015-01-01

    Long-period global-scale electromagnetic induction studies of deep Earth conductivity are based almost exclusively on magnetovariational methods and require accurate models of external source spatial structure. We describe approaches to inverting for both the external sources and three-dimensional (3-D) conductivity variations and apply these methods to long-period (T≥1.2 days) geomagnetic observatory data. Our scheme involves three steps: (1) Observatory data from 60 years (only partly overlapping and with many large gaps) are reduced and merged into dominant spatial modes using a scheme based on frequency domain principal components. (2) Resulting modes are inverted for corresponding external source spatial structure, using a simplified conductivity model with radial variations overlain by a two-dimensional thin sheet. The source inversion is regularized using a physically based source covariance, generated through superposition of correlated tilted zonal (quasi-dipole) current loops, representing ionospheric source complexity smoothed by Earth rotation. Free parameters in the source covariance model are tuned by a leave-one-out cross-validation scheme. (3) The estimated data modes are inverted for 3-D Earth conductivity, assuming the source excitation estimated in step 2. Together, these developments constitute key components in a practical scheme for simultaneous inversion of the catalogue of historical and modern observatory data for external source spatial structure and 3-D Earth conductivity.

  19. 3D current source density imaging based on acoustoelectric effect: a simulation study using unipolar pulses

    PubMed Central

    Yang, Renhuan; Li, Xu; Liu, Jun; He, Bin

    2011-01-01

    It is of importance to image electrical activity and properties of biological tissues. Recently hybrid imaging modality combing ultrasound scanning and source imaging through the acousto-electric (AE) effect has generated considerable interest. Such modality has the potential to provide high spatial resolution current density imaging by utilizing the pressure induced AE resistivity change confined at the ultrasound focus. In this study, we investigate a novel 3-dimensional (3D) ultrasound current source density imaging (UCSDI) approach using unipolar ultrasound pulses. Utilizing specially designed unipolar ultrasound pulses and by combining AE signals associated to the local resistivity changes at the focusing point, we are able to reconstruct the 3D current density distribution with the boundary voltage measurements obtained while performing a 3D ultrasound scan. We have shown in computer simulation that using the present method, it is feasible to image with high spatial resolution an arbitrary 3D current density distribution in an inhomogeneous conductive media. PMID:21628774

  20. A Current Source Method For t(sub q) Measurement of Fast Switching Thyristors

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2006-01-01

    A current source driven circuit has been constructed to measure the turn-off time (t(sub q)) of fast-switching SiC thyristors. This circuit operates from a single power supply and a dual channel pulse generator to provide adjustment of forward current, magnitude and duration of reverse applied voltage, and rate of rise of reapplied forward voltage. Values of t(sub q) down to 100 ns can be resolved.

  1. Influence of the electron source distribution on field-aligned currents

    NASA Astrophysics Data System (ADS)

    Bruening, K.; Goertz, C. K.

    1985-01-01

    The field-aligned current density above a discrete auroral arc has been deduced from the downward electron flux and magnetic field measurements onboard the rocket Porcupine flight 4. Both measurements show that the field-aligned current density is, in spite of decreasing peak energies towards the edge of the arc, about 4 times higher there than in the center of the arc. This can be explained by using the single particle description for an anisotropic electron source distribution.

  2. The magnetospheric disturbance ring current as a source for probing the deep earth electrical conductivity

    USGS Publications Warehouse

    Campbell, W.H.

    1990-01-01

    Two current rings have been observed in the equatorial plane of the earth at times of high geomagnetic activity. An eastward current exists between about 2 and 3.5 earth radii (Re) distant, and a larger, more variable companion current exists between about 4 and 9 Re. These current regions are loaded during geomagnetic substorms. They decay, almost exponentially, after the cessation of the particle influx that attends the solar wind disturbance. This review focuses upon characteristics needed for intelligent use of the ring current as a source for induction probing of the earth's mantle. Considerable difficulties are found with the assumption that Dst is a ring-current index. ?? 1990 Birkha??user Verlag.

  3. INDEP approach for leakage reduction in nanoscale CMOS circuits

    NASA Astrophysics Data System (ADS)

    Sharma, Vijay Kumar; Pattanaik, Manisha; Raj, Balwinder

    2015-02-01

    Complementary metal oxide semiconductor (CMOS) technology scaling for improving speed and functionality turns leakage power one of the major concerns for nanoscale circuits design. The minimization of leakage power is a rising challenge for the design of the existing and future nanoscale CMOS circuits. This paper presents a novel, input-dependent, transistor-level, low leakage and reliable INput DEPendent (INDEP) approach for nanoscale CMOS circuits. INDEP approach is based on Boolean logic calculations for the input signals of the extra inserted transistors within the logic circuit. The gate terminals of extra inserted transistors depend on the primary input combinations of the logic circuits. The appropriate selection of input gate voltages of INDEP transistors are reducing the leakage current efficiently along with rail to rail output voltage swing. The important characteristic of INDEP approach is that it works well in both active as well as standby modes of the circuits. This approach overcomes the limitations created by the prevalent current leakage reduction techniques. The simulation results indicate that INDEP approach mitigates 41.6% and 35% leakage power for 1-bit full adder and ISCAS-85 c17 benchmark circuit, respectively, at 32 nm bulk CMOS technology node.

  4. Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications

    SciTech Connect

    Chacon-Golcher, Edwin

    2002-06-01

    This dissertation develops diverse research on small (diameter ~ few mm), high current density (J ~ several tens of mA/cm2) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed and built for these experiments. Results of average current density yield () at different operating conditions are presented for K+ and Cs+ contact ionization sources and potassium aluminum silicate sources. Maximum values for a K+ beam of ~90 mA/cm2 were observed in 2.3 μs pulses. Measurements of beam intensity profiles and emittances are included. Measurements of neutral particle desorption are presented at different operating conditions which lead to a better understanding of the underlying atomic diffusion processes that determine the lifetime of the emitter. Estimates of diffusion times consistent with measurements are presented, as well as estimates of maximum repetition rates achievable. Diverse studies performed on the composition and preparation of alkali aluminosilicate ion sources are also presented. In addition, this work includes preliminary work carried out exploring the viability of an argon plasma ion source and a bismuth metal vapor vacuum arc (MEVVA) ion source. For the former ion source, fast rise-times (~ 1 μs), high current densities (~ 100 mA/cm+) and low operating pressures (< 2 mtorr) were verified. For the latter, high but acceptable levels of beam emittance were measured (εn ≤ 0.006 π· mm · mrad) although measured currents differed from the desired ones (I ~ 5mA) by about a factor of 10.

  5. A new curvature compensation technique for CMOS voltage reference using |VGS| and ΔVBE

    NASA Astrophysics Data System (ADS)

    Xuemin, Li; Mao, Ye; Gongyuan, Zhao; Yun, Zhang; Yiqiang, Zhao

    2016-05-01

    A new mixed curvature compensation technique for CMOS voltage reference is presented, which resorts to two sub-references with complementary temperature characteristics. The first sub-reference is the source-gate voltage |VGS|p of a PMOS transistor working in the saturated region. The second sub-reference is the weighted sum of gate-source voltages |VGS|n of NMOS transistors in the subthreshold region and the difference between two base-emitter voltages ΔVBE of bipolar junction transistors (BJTs). The voltage reference implemented utilizing the proposed curvature compensation technique exhibits a low temperature coefficient and occupies a small silicon area. The proposed technique was verified in 0.18 μm standard CMOS process technology. The performance of the circuit has been measured. The measured results show a temperature coefficient as low as 12.7 ppm/°C without trimming, over a temperature range from -40 to 120 °C, and the current consumption is 50 μA at room temperature. The measured power-supply rejection ratio (PSRR) is -31.2 dB @ 100 kHz. The circuit occupies an area of 0.045 mm2. Project supported by the National Natural Science Foundation of China (No. 61376032).

  6. Design and implementation of a CMOS light pulse receiver cell array for spatial optical communications.

    PubMed

    Sarker, Md Shakowat Zaman; Itoh, Shinya; Hamai, Moeta; Takai, Isamu; Andoh, Michinori; Yasutomi, Keita; Kawahito, Shoji

    2011-01-01

    A CMOS light pulse receiver (LPR) cell for spatial optical communications is designed and evaluated by device simulations and a prototype chip implementation. The LPR cell consists of a pinned photodiode and four transistors. It works under sub-threshold region of a MOS transistor and the source terminal voltage which responds to the logarithm of the photo current are read out with a source follower circuit. For finding the position of the light spot on the focal plane, an image pixel array is embedded on the same plane of the LPR cell array. A prototype chip with 640 × 240 image pixels and 640 × 240 LPR cells is implemented with 0.18 μm CMOS technology. A proposed model of the transient response of the LPR cell agrees with the result of the device simulations and measurements. Both imaging at 60 fps and optical communication at the carrier frequency of 1 MHz are successfully performed. The measured signal amplitude and the calculation results of photocurrents show that the spatial optical communication up to 100 m is feasible using a 10 × 10 LED array.

  7. Design and Implementation of A CMOS Light Pulse Receiver Cell Array for Spatial Optical Communications

    PubMed Central

    Sarker, Md. Shakowat Zaman; Itoh, Shinya; Hamai, Moeta; Takai, Isamu; Andoh, Michinori; Yasutomi, Keita; Kawahito, Shoji

    2011-01-01

    A CMOS light pulse receiver (LPR) cell for spatial optical communications is designed and evaluated by device simulations and a prototype chip implementation. The LPR cell consists of a pinned photodiode and four transistors. It works under sub-threshold region of a MOS transistor and the source terminal voltage which responds to the logarithm of the photo current are read out with a source follower circuit. For finding the position of the light spot on the focal plane, an image pixel array is embedded on the same plane of the LPR cell array. A prototype chip with 640 × 240 image pixels and 640 × 240 LPR cells is implemented with 0.18 μm CMOS technology. A proposed model of the transient response of the LPR cell agrees with the result of the device simulations and measurements. Both imaging at 60 fps and optical communication at the carrier frequency of 1 MHz are successfully performed. The measured signal amplitude and the calculation results of photocurrents show that the spatial optical communication up to 100 m is feasible using a 10 × 10 LED array. PMID:22319398

  8. Langmuir probe diagnostics of plasma in high current electron cyclotron resonance proton ion source

    SciTech Connect

    Roychowdhury, P.; Kewlani, H.; Mishra, L.; Mittal, K. C.; Patil, D. S.

    2013-07-15

    A high current Electron Cyclotron Resonance (ECR) proton ion source has been developed for low energy high intensity proton accelerator at Bhabha Atomic Research Centre. Langmuir probe diagnostics of the plasma generated in this proton ion source is performed using Langmuir probe. The diagnostics of plasma in the ion source is important as it determines beam parameters of the ion source, i.e., beam current, emittance, and available species. The plasma parameter measurement in the ion source is performed in continuously working and pulsed mode using hydrogen as plasma generation gas. The measurement is performed in the ECR zone for operating pressure and microwave power range of 10{sup −4}–10{sup −3} mbar and 400–1000 W. An automated Langmuir probe diagnostics unit with data acquisition system is developed to measure these parameters. The diagnostics studies indicate that the plasma density and plasma electron temperature measured are in the range 5.6 × 10{sup 10} cm{sup −3} to 3.8 × 10{sup 11} cm{sup −3} and 4–14 eV, respectively. Using this plasma, ion beam current of tens of mA is extracted. The variations of plasma parameters with microwave power, gas pressure, and radial location of the probe have been studied.

  9. RF Sources for the ITER Ion Cyclotron Heating and Current Drive System

    SciTech Connect

    Hosea, J.; Brunkhorst, C.; Fredd, E.; Goulding, R. H.; Goulding, R. H.; Greenough, N.; Kung, C.; Rasmussen, D. A.; Swain, D. W.; Wilson, J. R.

    2005-10-04

    The RF source requirements for the ITER ion cyclotron (IC) heating and current drive system are very challenging ? 20 MW CW power into an antenna load with a VSWR of up to 2 over the frequency range of 35-65 MHz. For the two present antenna designs under consideration, 8 sources providing 2.5 MW each are to be employed. For these sources, the outputs of two final power amplifiers (FPAs), using the high power CPI 4CM2500KG tube, are combined with a 180? hybrid combiner to easily meet the ITER IC source requirements ? 2.5 MW is supplied at a VSWR of 2 at ? 70% of the maximum tube power available in class B operation. The cylindrical cavity configuration for the FPAs is quite compact so that the 8 combined sources fit into the space allocated at the ITER site with room to spare. The source configuration is described in detail and its projected operating power curves are presented. Although the CPI tube has been shown to be stable under high power operating conditions on many facilities, a test of the combined FPA source arrangement is in preparation using existing high power 30 MHz amplifiers to assure that this configuration can be made robustly stable for all phases at a VSWR up to 2. The possibility of using 12 sources to feed a suitably modified antenna design is also discussed in the context of providing flexibility for specifying the final IC antenna design.

  10. A cookbook for building a high-current dimpled H– magnetron source for accelerators

    DOE PAGES

    Bollinger, Daniel S.; Karns, Patrick R.; Tan, Cheng -Yang

    2015-10-30

    A high-current (>50 mA) dimpled H– magnetron source has been built at Fermilab for supplying H– beam to the entire accelerator complex. Despite many decades of expertise with slit H– magnetron sources at Fermilab, we were faced with many challenges from the dimpled H– magnetron source, which needed to be overcome in order to make it operational. Dimpled H– sources for high-energy physics are not new: Brookhaven National Laboratory has operated a dimpled H- source for more than two decades. However, the transference of that experience to Fermilab took about two years because a cookbook for building this type ofmore » source did not exist and seemingly innocuous or undocumented choices had a huge impact on the success or failure for this type of source. Moreover, it is the goal of this paper to document the reasons for these choices and to present a cookbook for building and operating dimpled H– magnetron sources.« less

  11. Nodal Analysis Optimization Based on the Use of Virtual Current Sources: A Powerful New Pedagogical Method

    ERIC Educational Resources Information Center

    Chatzarakis, G. E.

    2009-01-01

    This paper presents a new pedagogical method for nodal analysis optimization based on the use of virtual current sources, applicable to any linear electric circuit (LEC), regardless of its complexity. The proposed method leads to straightforward solutions, mostly arrived at by inspection. Furthermore, the method is easily adapted to computer…

  12. Nodal Analysis Optimization Based on the Use of Virtual Current Sources: A Powerful New Pedagogical Method

    ERIC Educational Resources Information Center

    Chatzarakis, G. E.

    2009-01-01

    This paper presents a new pedagogical method for nodal analysis optimization based on the use of virtual current sources, applicable to any linear electric circuit (LEC), regardless of its complexity. The proposed method leads to straightforward solutions, mostly arrived at by inspection. Furthermore, the method is easily adapted to computer…

  13. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    NASA Astrophysics Data System (ADS)

    Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  14. Reliability of quantitative EEG (qEEG) measures and LORETA current source density at 30 days.

    PubMed

    Cannon, Rex L; Baldwin, Debora R; Shaw, Tiffany L; Diloreto, Dominic J; Phillips, Sherman M; Scruggs, Annie M; Riehl, Timothy C

    2012-06-14

    There is a growing interest for using quantitative EEG and LORETA current source density in clinical and research settings. Importantly, if these indices are to be employed in clinical settings then the reliability of these measures is of great concern. Neuroguide (Applied Neurosciences) is sophisticated software developed for the analyses of power, and connectivity measures of the EEG as well as LORETA current source density. To date there are relatively few data evaluating topographical EEG reliability contrasts for all 19 channels and no studies have evaluated reliability for LORETA calculations. We obtained 4 min eyes-closed and eyes-opened EEG recordings at 30-day intervals. The EEG was analyzed in Neuroguide and FFT power, coherence and phase was computed for traditional frequency bands (delta, theta, alpha and beta) and LORETA current source density was calculated in 1 Hz increments and summed for total power in eight regions of interest (ROI). In order to obtain a robust measure of reliability we utilized a random effects model with an absolute agreement definition. The results show very good reproducibility for total absolute power and coherence. Phase shows lower reliability coefficients. LORETA current source density shows very good reliability with an average 0.81 for ECB and 0.82 for EOB. Similarly, the eight regions of interest show good to very good agreement across time. Implications for future directions and use of qEEG and LORETA in clinical populations are discussed. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  15. An RF Energy Harvester System Using UHF Micropower CMOS Rectifier Based on a Diode Connected CMOS Transistor

    PubMed Central

    Shokrani, Mohammad Reza; Hamidon, Mohd Nizar B.; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18 μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology. PMID:24782680

  16. A Differential CMOS Common-Gate LNA Linearized by Cross-Coupled Post Distortion Technique

    NASA Astrophysics Data System (ADS)

    Guo, Benqing; Yang, Guomin; Bin, Xiexian

    2014-05-01

    A linearized differential common-gate CMOS low noise amplifier is proposed. The linearity is improved by a cross-coupled post distortion technique, employing auxiliary PMOS transistors in weak inversion region to cancel the third-order nonlinear currents of common-gate LNA and impair the second-order nonlinear currents of that. The negative conductance characteristic of cross-coupled auxiliary PMOS transistors improves the gain while the resulted NF is little affected. Furthermore, noise contribution and linearity deterioration from the cascode stage is eliminated by an inductor resonating with the parasitic capacitance observed at the source net of the cascode transistor. The LNA implemented in a 0.18 μm CMOS technology demonstrates that IIP3 and gain have about 8.2 dB and 1.4 dB improvements in the designed frequency band, respectively. The noise figure of 3.4 dB is obtained with a power dissipation of 6.8 mW under a 1.8 V power supply.

  17. Current State and Future Perspectives of Energy Sources for Totally Implantable Cardiac Devices.

    PubMed

    Bleszynski, Peter A; Luc, Jessica G Y; Schade, Peter; PhilLips, Steven J; Tchantchaleishvili, Vakhtang

    There is a large population of patients with end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. Implantable cardiac devices, many designated as destination therapy, have revolutionized patient care and outcomes, although infection and complications related to external power sources or routine battery exchange remain a substantial risk. Complications from repeat battery replacement, power failure, and infections ultimately endanger the original objectives of implantable biomedical device therapy - eliminating the intended patient autonomy, affecting patient quality of life and survival. We sought to review the limitations of current cardiac biomedical device energy sources and discuss the current state and trends of future potential energy sources in pursuit of a lifelong fully implantable biomedical device.

  18. A current-source inverter fed induction motor drive system with reduced losses

    SciTech Connect

    Espinoza, J.R.; Joos, G.

    1995-12-31

    Standard low and medium induction power motor drives are based on the PWM voltage source inverter (VSI) fed from a diode rectifier. The dual topology, based on the current source inverter/rectifier structure is used in medium and high power applications. This paper addresses some of the drawbacks of this approach compared to the voltage source approach. The proposed drive features: (a) an on-line operated PWM inverter, using instantaneous output capacitor voltage control based on space vector modulation; (b) a line-synchronized PWM rectifier, with dc bus current control; (c) an additional inverter modulation index control loop, ensuring a constant inverter modulation index. The resulting advantages include: (a) ruggedness and inherent continuous regeneration capability; (b) near unity global input power factor; (c) reduced motor voltage distortion; (d) reduced dc bus inductor and switch conduction losses; (e) fast motor dynamic response; (f) elimination of motor circuit resonances. Simulated and experimental results based on a DSP implementation are given.

  19. The source altitude, electric current, and intrinsic brightness of terrestrial gamma ray flashes

    NASA Astrophysics Data System (ADS)

    Cummer, Steven A.; Briggs, Michael S.; Dwyer, Joseph R.; Xiong, Shaolin; Connaughton, Valerie; Fishman, Gerald J.; Lu, Gaopeng; Lyu, Fanchao; Solanki, Rahulkumar

    2014-12-01

    Many details of how thunderstorms generate terrestrial gamma ray flashes (TGFs) and other forms of high-energy radiation remain uncertain, including the basic question of where they are produced. We exploit the association of distinct low-frequency radio emissions with generation of terrestrial gamma ray flashes (TGFs) to directly measure for the first time the TGF source altitude. Analysis of two events reveals source altitudes of 11.8 ± 0.4 km and 11.9 ± 0.9 km. This places the source region in the interior of the thunderstorm between the two main charge layers and implies an intrinsic TGF brightness of approximately 1018 runaway electrons. The electric current in this nontraditional lightning process is found to be strong enough to drive nonlinear effects in the ionosphere, and in one case is comparable to the highest peak current lightning processes on the planet.

  20. Steps toward fabricating cryogenic CMOS compatible single electron devices for future qubits.

    SciTech Connect

    Wendt, Joel Robert; Childs, Kenton David; Ten Eyck, Gregory A.; Tracy, Lisa A.; Eng, Kevin; Stevens, Jeffrey; Nordberg, Eric; Carroll, Malcolm S.; Lilly, Michael Patrick

    2008-08-01

    We describe the development of a novel silicon quantum bit (qubit) device architecture that involves using materials that are compatible with a Sandia National Laboratories (SNL) 0.35 mum complementary metal oxide semiconductor (CMOS) process intended to operate at 100 mK. We describe how the qubit structure can be integrated with CMOS electronics, which is believed to have advantages for critical functions like fast single electron electrometry for readout compared to current approaches using radio frequency techniques. Critical materials properties are reviewed and preliminary characterization of the SNL CMOS devices at 4.2 K is presented.

  1. Quantification of Shallow-junction Dopant Loss during CMOS Process

    SciTech Connect

    Buh, G.H.; Park, T.; Jee, Y.; Hong, S.J.; Ryoo, C.; Yoo, J.; Lee, J.W.; Yon, G.H.; Jun, C.S.; Shin, Y.G.; Chung, U.-In; Moon, J.T.

    2005-09-09

    We analyzed dopant concentration and profiles in source drain extension (SDE) by using in-line low energy electron induced x-ray emission spectrometry (LEXES), four point probe (FPP), and secondary ion mass spectroscopy (SIMS). By monitoring the dopant dose with LEXES, dopant loss in implantation and annealing process was successfully quantified. To measure the actual SDE sheet resistance in CMOS device structure without probe penetration in FPP, we fabricated a simple SDE sheet-resistance test structure (SSTS) by modifying a conventional CMOS process. It was found that the sheet resistances determined with SSTS are larger than those measured with FPP. There are three mechanisms of dopants loss in CMOS process: 1) wet-etching removal during photo resist cleaning, 2) out-diffusion, and 3) deactivation by post-thermal process. We quantified the loss of the dopant in SDE during the CMOS process, and found that the wet-etching removal and out-diffusion are the most significant causes for dopant loss in n-SDE and p-SDE, respectively.

  2. Fabrication and Characterization of CMOS-MEMS Thermoelectric Micro Generators

    PubMed Central

    Kao, Pin-Hsu; Shih, Po-Jen; Dai, Ching-Liang; Liu, Mao-Chen

    2010-01-01

    This work presents a thermoelectric micro generator fabricated by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and the post-CMOS process. The micro generator is composed of 24 thermocouples in series. Each thermocouple is constructed by p-type and n-type polysilicon strips. The output power of the generator depends on the temperature difference between the hot and cold parts in the thermocouples. In order to prevent heat-receiving in the cold part in the thermocouples, the cold part is covered with a silicon dioxide layer with low thermal conductivity to insulate the heat source. The hot part of the thermocouples is suspended and connected to an aluminum plate, to increases the heat-receiving area in the hot part. The generator requires a post-CMOS process to release the suspended structures. The post-CMOS process uses an anisotropic dry etching to remove the oxide sacrificial layer and an isotropic dry etching to etch the silicon substrate. Experimental results show that the micro generator has an output voltage of 67 μV at the temperature difference of 1 K. PMID:22205869

  3. Fabrication and characterization of CMOS-MEMS thermoelectric micro generators.

    PubMed

    Kao, Pin-Hsu; Shih, Po-Jen; Dai, Ching-Liang; Liu, Mao-Chen

    2010-01-01

    This work presents a thermoelectric micro generator fabricated by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and the post-CMOS process. The micro generator is composed of 24 thermocouples in series. Each thermocouple is constructed by p-type and n-type polysilicon strips. The output power of the generator depends on the temperature difference between the hot and cold parts in the thermocouples. In order to prevent heat-receiving in the cold part in the thermocouples, the cold part is covered with a silicon dioxide layer with low thermal conductivity to insulate the heat source. The hot part of the thermocouples is suspended and connected to an aluminum plate, to increases the heat-receiving area in the hot part. The generator requires a post-CMOS process to release the suspended structures. The post-CMOS process uses an anisotropic dry etching to remove the oxide sacrificial layer and an isotropic dry etching to etch the silicon substrate. Experimental results show that the micro generator has an output voltage of 67 μV at the temperature difference of 1 K.

  4. CMOS in-pixel optical pulse frequency modulator

    NASA Astrophysics Data System (ADS)

    Nel, Nicolaas E.; du Plessis, M.; Joubert, T.-H.

    2016-02-01

    This paper covers the design of a complementary metal oxide semiconductor (CMOS) pixel readout circuit with a built-in frequency conversion feature. The pixel contains a CMOS photo sensor along with all signal-to-frequency conversion circuitry. An 8×8 array of these pixels is also designed. Current imaging arrays often use analog-to-digital conversion (ADC) and digital signal processing (DSP) techniques that are off-chip1. The frequency modulation technique investigated in this paper is preferred over other ADC techniques due to its smaller size, and the possibility of a higher dynamic range. Careful considerations are made regarding the size of the components of the pixel, as various characteristics of CMOS devices are limited by decreasing the scale of the components2. The methodology used was the CMOS design cycle for integrated circuit design. All components of the pixel were designed from first principles to meet necessary requirements of a small pixel size (30×30 μm2) and an output resolution greater than that of an 8-bit ADC. For the photodetector, an n+-p+/p-substrate diode was designed with a parasitic capacitance of 3 fF. The analog front-end stage was designed around a Schmitt trigger circuit. The photo current is integrated on an integration capacitor of 200 fF, which is reset when the Schmitt trigger output voltage exceeds a preset threshold. The circuit schematic and layout were designed using Cadence Virtuoso and the process used was the AMS CMOS 350 nm process using a power supply of 5V. The simulation results were confirmed to comply with specifications, and the layout passed all verification checks. The dynamic range achieved is 58.828 dB per pixel, with the output frequencies ranging from 12.341kHz to 10.783 MHz. It is also confirmed that the output frequency has a linear relationship to the photocurrent generated by the photodiode.

  5. Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time.

    PubMed

    Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

    2016-03-01

    Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

  6. Bootstrap current in enhanced reversed shear tokamaks for volume neutron source applications

    SciTech Connect

    Houlberg, W.A.

    1995-12-31

    The bootstrap current is evaluated for two reference tokamak designs for a Volume Neutron Source (VNS). One is a larger aspect ratio design using superconducting coils (VNS-SC) and the other is a small aspect ratio design using a solid core with normal conducting toroidal field coils (VNS-ST). The target plasma profiles are taken as representative of the recently observed enhanced reverse shear plasmas with hollow magnetic safety factor (q) profiles in the core and corresponding peaked density profiles. The higher q in the plasma center in combination with peaked density is shown to move the peak in the bootstrap current toward the plasma center. This reduces the current drive requirements to a very small axial seed current and a source localized around the location of the desired minimum in the q profile. Very high bootstrap current fractions can be attained in the VNS-SC design with normalized betas (defined in terms of the vacuum toroidal magnetic field at the geometric center of the plasma) of {beta}{sub N} {le} 3.5. The bootstrap current is lower in the VNS-ST design because of its lower aspect ratio; the highest bootstrap fraction found in these limited cases is 50% at {beta}{sub N} = 5.

  7. Three-dimensional brain current source reconstruction from intra-cranial ECoG recordings.

    PubMed

    Zhang, Yingchun; van Drongelen, Wim; Kohrman, Michael; He, Bin

    2008-08-15

    We have investigated 3-dimensional brain current density reconstruction (CDR) from intracranial electrocorticogram (ECoG) recordings by means of finite element method (FEM). The brain electrical sources are modeled by a current density distribution and estimated from the ECoG signals with the aid of a weighted minimum norm estimation algorithm. A series of computer simulations were conducted to evaluate the performance of ECoG-CDR by comparing with the scalp EEG based CDR results. The present computer simulation results indicate that the ECoG-CDR provides enhanced performance in localizing single dipole sources which are located in regions underneath the implanted subdural ECoG grids, and in distinguishing and imaging multiple separate dipole sources, in comparison to the CDR results as obtained from the scalp EEG under the same conditions. We have also demonstrated the applicability of the present ECoG-CDR method to estimate 3-dimensional current density distribution from the subdural ECoG recordings in a human epilepsy patient. Eleven interictal epileptiform spikes (seven from the frontal region and four from parietal region) in an epilepsy patient undergoing surgical evaluation were analyzed. The present promising results indicate the feasibility and applicability of the developed ECoG-CDR method of estimating brain sources from intracranial electrical recordings, with detailed forward modeling using FEM.

  8. Spectral factorization-based current source density analysis of ongoing neural oscillations.

    PubMed

    Chand, Ganesh B; Dhamala, Mukesh

    2014-03-15

    Current source density (CSD) analysis is widely used in neurophysiological investigations intended to reveal the patterns of localized neuronal activity in terms of current sources and sinks. CSD is based on the second spatial derivatives of multi-electrode electrophysiological recordings, and can be applied to brain activity related to repeated external stimulations (evoked brain activity) or ongoing (spontaneous) brain activity. In evoked brain activity, event-related time-series averages of ensembles are used to compute CSD patterns. However, for ongoing neural activity, the lack of external events requires a different approach other than ensemble averaging. Here, we propose a new spectral factorization-based current source density (SF-CSD) analysis method for ongoing neural oscillations. We validated this new SF-CSD analysis method using simulated data and demonstrated its effectiveness by applying to experimental intra-cortical local field potentials recorded on multi-contact depth electrodes from monkeys performing selective visual attention tasks. The proposed method gives space-unbiased estimates since it does not rely on a reference for CSD calculation in the frequency-domain. The proposed SF-CSD method is expected to be a useful tool for systematic analysis of neural sources and oscillations from multi-site electrophysiological recordings. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. TID Simulation of Advanced CMOS Devices for Space Applications

    NASA Astrophysics Data System (ADS)

    Sajid, Muhammad

    2016-07-01

    This paper focuses on Total Ionizing Dose (TID) effects caused by accumulation of charges at silicon dioxide, substrate/silicon dioxide interface, Shallow Trench Isolation (STI) for scaled CMOS bulk devices as well as at Buried Oxide (BOX) layer in devices based on Silicon-On-Insulator (SOI) technology to be operated in space radiation environment. The radiation induced leakage current and corresponding density/concentration electrons in leakage current path was presented/depicted for 180nm, 130nm and 65nm NMOS, PMOS transistors based on CMOS bulk as well as SOI process technologies on-board LEO and GEO satellites. On the basis of simulation results, the TID robustness analysis for advanced deep sub-micron technologies was accomplished up to 500 Krad. The correlation between the impact of technology scaling and magnitude of leakage current with corresponding total dose was established utilizing Visual TCAD Genius program.

  10. A CMOS Sub-GHz Wideband Low-Noise Amplifier for Digital TV Tuner Applications

    NASA Astrophysics Data System (ADS)

    Cha, Hyouk-Kyu

    A high performance highly integrated sub-GHz wideband differential low-noise amplifier (LNA) for terrestrial and cable digital TV tuner applications is realized in 0.18µm CMOS technology. A noise-canceling topology using a feed-forward current reuse common-source stage is presented to obtain low noise characteristics and high gain while achieving good wideband input matching within 48-860MHz. In addition, linearization methods are appropriately utilized to improve the linearity. The implemented LNA achieves a power gain of 20.9dB, a minimum noise figure of 2.8dB, and an OIP3 of 24.2dBm. The chip consumes 32mA of current at 1.8V power supply and the core die size is 0.21mm2.

  11. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    PubMed

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Impurities, temperature, and density in a miniature electrostatic plasma and current source

    SciTech Connect

    Den Hartog, D.J.; Craig, D.J.; Fiksel, G.; Sarff, J.S.

    1996-10-01

    We have spectroscopically investigated the Sterling Scientific miniature electrostatic plasma source-a plasma gun. This gun is a clean source of high density (10{sup 19} - 10{sup 20} m{sup -3}), low temperature (5 - 15 eV) plasma. A key result of our investigation is that molybdenum from the gun electrodes is largely trapped in the internal gun discharge; only a small amount escapes in the plasma flowing out of the gun. In addition, the gun plasma parameters actually improve (even lower impurity contamination and higher ion temperature) when up to 1 kA of electron current is extracted from the gun via the application of an external bias. This improvement occurs because the internal gun anode no longer acts as the current return for the internal gun discharge. The gun plasma is a virtual plasma electrode capable of sourcing an electron emission current density of 1 kA/cm{sup 2}. The high emission current, small size (3 - 4 cm diameter), and low impurity generation make this gun attractive for a variety of fusion and plasma technology applications.

  13. Extracted beam and electrode currents in the inductively driven surface-plasma negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Belchenko, Yu.; Ivanov, A.; Sanin, A.; Sotnikov, O.

    2017-08-01

    The data on long-pulsed operation of RF surface-plasma source is presented. The source regularly produces the H- ion beam with current >1A, energy ≥90 keV and pulse duration ≥2 s. The total H- beam curent, transported to the distant Faraday cup and the currents in the circuits of ion-optical system elements were measured. The composition of accelerated and extracted grid currents was clarified. The relatively high level of acceleration grid current 0.4 A was observed. It consists mainly of secondary electrons, emitted from extraction grid apertures and stripped from H- ions and could be decreased by optimization of positive PG bias applied. The test stand experiments on beam transport through the LEBT were carried out. About 90% of the H- ion beam was transported from the source to the distant calorimeter plane. The full size of 93 keV beam, transported to the calorimeter plane, was larger, than the size of the calorimeter inlet window. As a result, ˜ 60% of the initial beam power was registered by the calorimeter with window 24×24 cm2.

  14. Digital-Centric RF CMOS Technologies

    NASA Astrophysics Data System (ADS)

    Matsuzawa, Akira

    Analog-centric RFCMOS technology has played an important role in motivating the change of technology from conventional discrete device technology or bipolar IC technology to CMOS technology. However it introduces many problems such as poor performance, susceptibility to PVT fluctuation, and cost increase with technology scaling. The most important advantage of CMOS technology compared with legacy RF technology is that CMOS can use more high performance digital circuits for very low cost. In fact, analog-centric RF-CMOS technology has failed the FM/AM tuner business and the digital-centric CMOS technology is becoming attractive for many users. It has many advantages; such as high performance, no external calibration points, high yield, and low cost. From the above facts, digital-centric CMOS technology which utilizes the advantages of digital technology must be the right path for future RF technology. Further investment in this technology is necessary for the advancement of RF technology.

  15. Portable design rules for bulk CMOS

    NASA Technical Reports Server (NTRS)

    Griswold, T. W.

    1982-01-01

    It is pointed out that for the past several years, one school of IC designers has used a simplified set of nMOS geometric design rules (GDR) which is 'portable', in that it can be used by many different nMOS manufacturers. The present investigation is concerned with a preliminary set of design rules for bulk CMOS which has been verified for simple test structures. The GDR are defined in terms of Caltech Intermediate Form (CIF), which is a geometry-description language that defines simple geometrical objects in layers. The layers are abstractions of physical mask layers. The design rules do not presume the existence of any particular design methodology. Attention is given to p-well and n-well CMOS processes, bulk CMOS and CMOS-SOS, CMOS geometric rules, and a description of the advantages of CMOS technology.

  16. Research on evaluation method of CMOS camera

    NASA Astrophysics Data System (ADS)

    Zhang, Shaoqiang; Han, Weiqiang; Cui, Lanfang

    2014-09-01

    In some professional image application fields, we need to test some key parameters of the CMOS camera and evaluate the performance of the device. Aiming at this requirement, this paper proposes a perfect test method to evaluate the CMOS camera. Considering that the CMOS camera has a big fixed pattern noise, the method proposes the `photon transfer curve method' based on pixels to measure the gain and the read noise of the camera. The advantage of this method is that it can effectively wipe out the error brought by the response nonlinearity. Then the reason of photoelectric response nonlinearity of CMOS camera is theoretically analyzed, and the calculation formula of CMOS camera response nonlinearity is deduced. Finally, we use the proposed test method to test the CMOS camera of 2560*2048 pixels. In addition, we analyze the validity and the feasibility of this method.

  17. CMOS output buffer wave shaper

    NASA Technical Reports Server (NTRS)

    Albertson, L.; Whitaker, S.; Merrell, R.

    1990-01-01

    As the switching speeds and densities of Digital CMOS integrated circuits continue to increase, output switching noise becomes more of a problem. A design technique which aids in the reduction of switching noise is reported. The output driver stage is analyzed through the use of an equivalent RLC circuit. The results of the analysis are used in the design of an output driver stage. A test circuit based on these techniques is being submitted to MOSIS for fabrication.

  18. Cryogenic CMOS circuits for single charge digital readout.

    SciTech Connect

    Gurrieri, Thomas M.; Longoria, Erin Michelle; Eng, Kevin; Carroll, Malcolm S.; Hamlet, Jason R.; Young, Ralph Watson

    2010-03-01

    The readout of a solid state qubit often relies on single charge sensitive electrometry. However the combination of fast and accurate measurements is non trivial due to large RC time constants due to the electrometers resistance and shunt capacitance from wires between the cold stage and room temperature. Currently fast sensitive measurements are accomplished through rf reflectrometry. I will present an alternative single charge readout technique based on cryogenic CMOS circuits in hopes to improve speed, signal-to-noise, power consumption and simplicity in implementation. The readout circuit is based on a current comparator where changes in current from an electrometer will trigger a digital output. These circuits were fabricated using Sandia's 0.35 {micro}m CMOS foundry process. Initial measurements of comparators with an addition a current amplifier have displayed current sensitivities of < 1nA at 4.2K, switching speeds up to {approx}120ns, while consuming {approx}10 {micro}W. I will also discuss an investigation of noise characterization of our CMOS process in hopes to obtain a better understanding of the ultimate limit in signal to noise performance.

  19. Arsenic ion implant energy effects on CMOS gate oxide hardness.

    SciTech Connect

    Dondero, Richard; Headley, Thomas Jeffrey; Young, Ralph Watson; Draper, Bruce Leroy; Shaneyfelt, Marty Ray

    2005-07-01

    Under conditions that were predicted as 'safe' by well-established TCAD packages, radiation hardness can still be significantly degraded by a few lucky arsenic ions reaching the gate oxide during self-aligned CMOS source/drain ion implantation. The most likely explanation is that both oxide traps and interface traps are created when ions penetrate and damage the gate oxide after channeling or traveling along polysilicon grain boundaries during the implantation process.

  20. Characterizations of and Radiation Effects in Several Emerging CMOS Technologies

    NASA Astrophysics Data System (ADS)

    Shufeng Ren

    As the conventional scaling of Si based CMOS is approaching its limit at 7 nm technology node, many perceive that the adoption of novel materials and/or device structures are inevitable to keep Moore's law going. High mobility channel materials such as III-V compound semiconductors or Ge are considered promising to replace Si in order to achieve high performance as well as low power consumption. However, interface and oxide traps have become a major obstacle for high-mobility semiconductors (such as Ge, GaAs, InGaAs, GaSb, etc) to replace Si CMOS technology. Therefore novel high-k dielectrics, such as epitaxially grown crystalline oxides, have been explored to be incorporated onto the high mobility channel materials. Moreover, to enable continued scaling, extremely scaled devices structures such as nanowire gate-all-around structure are needed in the near future. Moreover, as the CMOS industry moves into the 7 nm node and beyond, novel lithography techniques such as EUV are believed to be adopted soon, which can bring radiation damage to CMOS devices and circuit during the fabrication process. Therefore radiation hardening technology in future generations of CMOS devices has again become an interesting research topic to deal with the possible process-induced damage as well as damage caused by operating in radiation harsh environment such as outer space, nuclear plant, etc. In this thesis, the electrical properties of a few selected emerging novel CMOS devices are investigated, which include InGaAs based extremely scaled ultra-thin body nanowire gate-all-around MOSFETs, GOI (Ge On Insulator) CMOS with recessed channel and source/drain, GaAs MOSFETs with crystalline La based gate stack, and crystalline SrTiO3, are investigated to extend our understanding of their electrical characteristics, underlying physical mechanisms, and material properties. Furthermore, the radiation responses of these aforementioned novel devices are thoroughly investigated, with a focus on

  1. A single-supply, monolithic, MIL-STD-1553 transceiver implemented in BiCMOS wafer fabrication technology

    NASA Astrophysics Data System (ADS)

    Albrecht, Thomas L.; Molinari, Lou

    An integrated circuit has been designed for use as a single supply, MIL-STD-1553 transceiver using BiCMOS technology. Use of the BiCMOS fabrication process has advantages over both Bipolar and CMOS technologies. These advantages include: reduced standby current drain, increased flexibility in mating the transceiver to various remote terminals, increased control over output amplitude and rise/fall times, easier methods for adjusting filter response and residual voltage, and reduced chip size (over a CMOS transceiver). Development of this monolithic transceiver opens the door to future advances in remote terminal design. By combining the current driving capacity of Bipolar with the digital design capability of CMOS, the next probable step in the progression of MIL-STD-1553 technology would be a fully monolithic remote terminal. This device would combine a transceiver with the encoder/decoder and protocol logic on a single semiconductor device.

  2. Variation-based sparse cortical current density imaging in estimating cortical sources with MEG data.

    PubMed

    Ding, Lei; Zhu, Min; Zhang, Wenbo; Dickens, Deanna L

    2010-01-01

    We investigated the performance of a new sparse neuroimaging method, i.e., Variation-Based Sparse Cortical Current Density (VB-SCCD) using magnetoencephalography (MEG) data to reconstruct extended cortical sources and their spatial distributions on the cortical surface. We conducted Monte Carlo simulation studies to compare the performance of the VB-SCCD method with different number of cortical sources and different number of MEG sensors. Our simulation data suggests that the VB-SCCD method is able to reconstruct extended cortical sources with the overall accuracy, while it has significantly reduced performance when cortical sources are radially oriented to MEG sensors. It has higher accuracy when the number of sensors is large and the source configuration is simple. We further assess the performance of VB-SCCD in real MEG data from an epilepsy patient and reconstructed cortical sources behind interictal spikes from the patient which are consistent with the clinical evaluation outcomes. This data indicate its promising applications in clinical problems related to neurological disorders.

  3. Effect of tides and source location on nearshore tsunami-induced currents

    NASA Astrophysics Data System (ADS)

    Ayca, Aykut; Lynett, Patrick J.

    2016-12-01

    Here we present the results of a numerical modeling study that investigates how event-maximum tsunami-induced currents vary due to the dynamic effects of tides and wave directivity. First, analyses of tide-tsunami interaction are presented in three harbors by coupling the tsunami with the tide, and allowing the initial tsunami wave to arrive at various tidal phases. We find that tsunami-tide interaction can change the event-maximum current speed experienced in a harbor by up to 25% for the events and harbors studied, and we note that this effect is highly site-specific. Second, to evaluate the effect of wave directionality on event-maximum currents, earthquakes sources were placed throughout the Pacific, with magnitudes tuned to create the same maximum near-coast amplitude at the harbor of study. Our analysis also shows that, for the harbor and sources examined, the effect of offshore directionality and tsunami frequency content has a weak effect on the event-maximum currents experienced in the harbor. The more important dependency of event-maximum currents is the near-harbor amplitude of the wave, indicating that event-maximum currents in a harbor from a tsunami generated by a large far-field earthquake may be reasonably well predicted with only information about the predicted local maximum tsunami amplitude. This study was motivated by the hope of constructing a basis for understanding the dynamic effects of tides and wave directivity on current-based tsunami hazards in a coastal zone. The consideration of these aspects is crucial and yet challenging in the modeling of tsunami currents.

  4. Passive radiation detection using optically active CMOS sensors

    NASA Astrophysics Data System (ADS)

    Dosiek, Luke; Schalk, Patrick D.

    2013-05-01

    Recently, there have been a number of small-scale and hobbyist successes in employing commodity CMOS-based camera sensors for radiation detection. For example, several smartphone applications initially developed for use in areas near the Fukushima nuclear disaster are capable of detecting radiation using a cell phone camera, provided opaque tape is placed over the lens. In all current useful implementations, it is required that the sensor not be exposed to visible light. We seek to build a system that does not have this restriction. While building such a system would require sophisticated signal processing, it would nevertheless provide great benefits. In addition to fulfilling their primary function of image capture, cameras would also be able to detect unknown radiation sources even when the danger is considered to be low or non-existent. By experimentally profiling the image artifacts generated by gamma ray and β particle impacts, algorithms are developed to identify the unique features of radiation exposure, while discarding optical interaction and thermal noise effects. Preliminary results focus on achieving this goal in a laboratory setting, without regard to integration time or computational complexity. However, future work will seek to address these additional issues.

  5. TRIASSIC: the Time-Resolved Industrial Alpha-Source Scanning Induced Current microscope

    NASA Astrophysics Data System (ADS)

    Pallone, Arthur

    Time-resolved ion beam induced current (TRIBIC) microscopy yields useful information such as carrier mobility and lifetimes in semiconductors and defect locations in devices; however, traditional TRIBIC uses large, expensive particle accelerators that require specialized training to operate and maintain. The time-resolved industrial alpha-source scanning induced current (TRIASSIC) microscope transforms TRIBIC by replacing the particle accelerator facility with an affordable, tabletop instrument suitable for use in research and education at smaller colleges and universities. I will discuss the development of, successes with, setbacks to and future directions for TRIASSIC.

  6. Interharmonics injected by current source inverters of a ship's propulsion system

    NASA Astrophysics Data System (ADS)

    Bourguet, S.; Guerin, P.; Rannou, C.

    2008-02-01

    Current source inverters (CSI) associated to rectifiers are used in variable speed drives for the propulsion system onboard ships. The complete structure will generate frequency perturbations in the entire supply system which could become undesirable. In a first part, the modulation theory is applied to the ideal structure of a converter. The designs of the propulsion transformers and of the propulsion motor are considered in order to calculate the injected currents on both sides of the converters. Finally, those results are confronted to experimental ones obtained onboard an electric ship. Those results show a complete validation of the theoretical predictions.

  7. CMOS Image Sensors for High Speed Applications.

    PubMed

    El-Desouki, Munir; Deen, M Jamal; Fang, Qiyin; Liu, Louis; Tse, Frances; Armstrong, David

    2009-01-01

    Recent advances in deep submicron CMOS technologies and improved pixel designs have enabled CMOS-based imagers to surpass charge-coupled devices (CCD) imaging technology for mainstream applications. The parallel outputs that CMOS imagers can offer, in addition to complete camera-on-a-chip solutions due to being fabricated in standard CMOS technologies, result in compelling advantages in speed and system throughput. Since there is a practical limit on the minimum pixel size (4∼5 μm) due to limitations in the optics, CMOS technology scaling can allow for an increased number of transistors to be integrated into the pixel to improve both detection and signal processing. Such smart pixels truly show the potential of CMOS technology for imaging applications allowing CMOS imagers to achieve the image quality and global shuttering performance necessary to meet the demands of ultrahigh-speed applications. In this paper, a review of CMOS-based high-speed imager design is presented and the various implementations that target ultrahigh-speed imaging are described. This work also discusses the design, layout and simulation results of an ultrahigh acquisition rate CMOS active-pixel sensor imager that can take 8 frames at a rate of more than a billion frames per second (fps).

  8. The CMOS integration of a power inverter

    NASA Astrophysics Data System (ADS)

    Mannarino, Eric Francis

    Due to their falling costs, the use of renewable energy systems is expanding around the world. These systems require the conversion of DC power into grid-synchronous AC power. Currently, the inverters that carry out this task are built using discrete transistors. TowerJazz Semiconductor Corp. has created a commercial CMOS process that allows for blocking voltages of up to 700 V, effectively removing the barrier to integrating power inverters onto a single chip. This thesis explores this process using two topologies. The first is a cell-based switched-capacitor topology first presented by Ke Zou. The second is a novel topology that explores the advantage of using a bused input-output system, as in digital electronics. Simulations run on both topologies confirm the high-efficiency demonstrated in Zou’s process as well as the advantage the bus-based system has in output voltage levels.

  9. Delta-Doped Back-Illuminated CMOS Imaging Arrays: Progress and Prospects

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.; Jones, Todd J.; Dickie, Matthew R.; Greer, Frank; Cunningham, Thomas J.; Blazejewski, Edward; Nikzad, Shouleh

    2009-01-01

    In this paper, we report the latest results on our development of delta-doped, thinned, back-illuminated CMOS imaging arrays. As with charge-coupled devices, thinning and back-illumination are essential to the development of high performance CMOS imaging arrays. Problems with back surface passivation have emerged as critical to the prospects for incorporating CMOS imaging arrays into high performance scientific instruments, just as they did for CCDs over twenty years ago. In the early 1990's, JPL developed delta-doped CCDs, in which low temperature molecular beam epitaxy was used to form an ideal passivation layer on the silicon back surface. Comprising only a few nanometers of highly-doped epitaxial silicon, delta-doping achieves the stability and uniformity that are essential for high performance imaging and spectroscopy. Delta-doped CCDs were shown to have high, stable, and uniform quantum efficiency across the entire spectral range from the extreme ultraviolet through the near infrared. JPL has recently bump-bonded thinned, delta-doped CMOS imaging arrays to a CMOS readout, and demonstrated imaging. Delta-doped CMOS devices exhibit the high quantum efficiency that has become the standard for scientific-grade CCDs. Together with new circuit designs for low-noise readout currently under development, delta-doping expands the potential scientific applications of CMOS imaging arrays, and brings within reach important new capabilities, such as fast, high-sensitivity imaging with parallel readout and real-time signal processing. It remains to demonstrate manufacturability of delta-doped CMOS imaging arrays. To that end, JPL has acquired a new silicon MBE and ancillary equipment for delta-doping wafers up to 200mm in diameter, and is now developing processes for high-throughput, high yield delta-doping of fully-processed wafers with CCD and CMOS imaging devices.

  10. Delta-Doped Back-Illuminated CMOS Imaging Arrays: Progress and Prospects

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.; Jones, Todd J.; Dickie, Matthew R.; Greer, Frank; Cunningham, Thomas J.; Blazejewski, Edward; Nikzad, Shouleh

    2009-01-01

    In this paper, we report the latest results on our development of delta-doped, thinned, back-illuminated CMOS imaging arrays. As with charge-coupled devices, thinning and back-illumination are essential to the development of high performance CMOS imaging arrays. Problems with back surface passivation have emerged as critical to the prospects for incorporating CMOS imaging arrays into high performance scientific instruments, just as they did for CCDs over twenty years ago. In the early 1990's, JPL developed delta-doped CCDs, in which low temperature molecular beam epitaxy was used to form an ideal passivation layer on the silicon back surface. Comprising only a few nanometers of highly-doped epitaxial silicon, delta-doping achieves the stability and uniformity that are essential for high performance imaging and spectroscopy. Delta-doped CCDs were shown to have high, stable, and uniform quantum efficiency across the entire spectral range from the extreme ultraviolet through the near infrared. JPL has recently bump-bonded thinned, delta-doped CMOS imaging arrays to a CMOS readout, and demonstrated imaging. Delta-doped CMOS devices exhibit the high quantum efficiency that has become the standard for scientific-grade CCDs. Together with new circuit designs for low-noise readout currently under development, delta-doping expands the potential scientific applications of CMOS imaging arrays, and brings within reach important new capabilities, such as fast, high-sensitivity imaging with parallel readout and real-time signal processing. It remains to demonstrate manufacturability of delta-doped CMOS imaging arrays. To that end, JPL has acquired a new silicon MBE and ancillary equipment for delta-doping wafers up to 200mm in diameter, and is now developing processes for high-throughput, high yield delta-doping of fully-processed wafers with CCD and CMOS imaging devices.

  11. Microwave proton source development for a high-current linac injector

    SciTech Connect

    Sherman, J.; Bolme, G.; Geisik, C.

    1995-09-01

    Powerful CW proton linear accelerators (100-mA at 0.5--1.0 GeV) are being proposed for spallation neutron-source applications. A 75-keV, 110-mA dc proton injector using a microwave ion source is being tested for these applications. It has achieved 80-keV, 110-mA hydrogen-ion-beam operation. Video and dc beam-current toroid diagnostics are operational, and an EPICS control system is also operational on the 75-keV injector. A technical base development program has also been carried out on a 50-keV injector obtained from Chalk River Laboratories, and it includes low-energy beam transport studies, ion source lifetime tests, and proton-fraction enhancement studies. Technical base results and the present status of the 75-keV injector will be presented.

  12. Obtaining evidence beyond the current "special arrangement sources." Interim final rule with request for comments.

    PubMed

    2014-06-12

    We are amending our regulations to state that we will obtain evidence from any appropriate source. Our current regulations provide that we will obtain information from "special arrangement sources'' for those infrequent situations when we are in a better position than our State agency partners to obtain evidence. Due to improved evidence collection through our increased use of health information technology (health IT), we are obtaining evidence electronically with increasing frequency. We expect that, over time, the electronic exchange of medical records will become our primary means for obtaining medical evidence. As we increase our use of health IT, the designation of "special arrangement sources'' will no longer adequately describe from whom we collect evidence.

  13. Lexical knowledge sources for cartography and GIS - development, current status and outlook

    NASA Astrophysics Data System (ADS)

    Koch, Wolf Günther

    2016-12-01

    Lexical knowledge sources are indispensable for research, education and general information. The transition of the reference works to the digital world has been a gradual one. This paper discusses the basic principles and structure of knowledge presentation, as well as user access and knowledge acquisition with specific consideration of contributions in German. The ideal reference works of the future should be interactive, optimally adapted to the user, reliable, current and quotable.

  14. Inverse current-source density method in 3D: reconstruction fidelity, boundary effects, and influence of distant sources.

    PubMed

    Łeski, Szymon; Wójcik, Daniel K; Tereszczuk, Joanna; Swiejkowski, Daniel A; Kublik, Ewa; Wróbel, Andrzej

    2007-01-01

    Estimation of the continuous current-source density in bulk tissue from a finite set of electrode measurements is a daunting task. Here we present a methodology which allows such a reconstruction by generalizing the one-dimensional inverse CSD method. The idea is to assume a particular plausible form of CSD within a class described by a number of parameters which can be estimated from available data, for example a set of cubic splines in 3D spanned on a fixed grid of the same size as the set of measurements. To avoid specificity of particular choice of reconstruction grid we add random jitter to the points positions and show that it leads to a correct reconstruction. We propose different ways of improving the quality of reconstruction which take into account the sources located outside the recording region through appropriate boundary treatment. The efficiency of the traditional CSD and variants of inverse CSD methods is compared using several fidelity measures on different test data to investigate when one of the methods is superior to the others. The methods are illustrated with reconstructions of CSD from potentials evoked by stimulation of a bunch of whiskers recorded in a slab of the rat forebrain on a grid of 4x5x7 positions.

  15. Nanowatt-Power-Level Automatic Switch Combining ED-CMOS Circuit and LED

    NASA Astrophysics Data System (ADS)

    Utsunomiya, Fumiyasu; Douseki, Takakuni

    A nanowatt-power-level automatic switch that combines a multi-Vth CMOS level converter and an LED as a photodiode has been developed for a sensor application. The level converter is a single-input latch-type multi-Vth CMOS circuit featuring the use of an enhancement-mode nMOSFET and a depletion-mode common-gate nMOSFET as a pair of driver transistors. The ED-CMOS level converter cuts the DC current path; and the LED, which generates a high output voltage under illumination, suppresses the leakage current of the depletion-mode common-gate nMOSFET in the ED-CMOS level converter, resulting in nanowatt-order power dissipation. To verify the effectiveness of the ED-CMOS circuit, a prototype level converter was fabricated on a 0.6-µm CMOS process and used in an automatic switch in a wireless mouse. The switch is composed of two LEDs, a current-mirror circuit, the level converter, and a power switch MOSFET. It senses when a hand grabs or releases the mouse and automatically turns the mouse on or off, respectively. The measured power dissipation of the mouse is 3nW in the standby mode.

  16. N400 during lexical decision tasks: a current source localization study.

    PubMed

    Silva-Pereyra, Juan; Rivera-Gaxiola, Maritza; Aubert, Eduardo; Bosch, Jorge; Galán, Lidice; Salazar, Ariel

    2003-12-01

    Our primary aim in the present study was to establish the anatomic and psychophysiological correlates of automatic and controlled semantic priming. Current sources were calculated on N400 component data from a previous study on lexical decision tasks [Clin Neurophysiol 1999;110:813] using the variable resolution electromagnetic tomography method (VARETA). In this study, two experiments were carried out, one using directly related pairs and the other one using mediated related pairs. Each experiment consisted of 3 tasks that required different levels of contribution from controlled processes. Average source localization images showed the brain structures involved in lexical decision tasks. The automatic component of the N400 effect was related to activation of occipitotemporal and parahippocampal gyri and anterior temporal lobes bilaterally. The expectancy strategy was related to activation of the right posterior temporal and right frontal areas. The postlexical strategy was associated with activation of right frontal, anterior cingulate and bilateral superior parietal areas. The findings indicated that the current sources of the N400 varied according to the relative contributions of automatic and controlled mechanisms. Moreover, the sources of the N400 effect depended on the type of strategy used.

  17. Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources

    NASA Astrophysics Data System (ADS)

    Dong, Chenyin; Taylor, Mark Patrick

    2017-07-01

    Resolving the source of environmental contamination is the critical first step in remediation and exposure prevention. Australia's oldest silver-zinc-lead mine at Broken Hill (>130 years old) has generated a legacy of contamination and is associated with persistent elevated childhood blood lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum at Broken Hill include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 μg/m2/day) and its bioaccessibility (mean 75% of total Pb) is greatest adjacent to the active mining operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust particles were more angular, had higher sulfur content and had little or no iron and manganese. Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406) that are a close match (99%) to the ore body with values slightly lower (94%) at the edge of the city. The weight of evidence supports the conclusion that contemporary dust Pb contamination in Broken Hill is sourced primarily from current mining activities and not from weathering or legacy sources.

  18. An Enhanced Vacuum Arc Ion Source for High Current, High Charge State Uranium Beam Production

    NASA Astrophysics Data System (ADS)

    Johnson, B. M.; Hershcovitch, A.; Brown, I. G.; Leemans, W.; Liu, F.

    1996-05-01

    We plan to carry out an experimental program at LBNL to develop a novel kind of vacuum arc ion source in which the metal ions are further stripped by interaction with an energetic, dense electron beam. Preliminary results obtained by Batalin et al.(V. A. Batalin, Y. N. Volkov, T. V. Kulevoy, and S. V. Petrenko, ITEP, Moscow, Reprints 18-93 (1993), 33-94 (1994); Proc. EPAC 1994, p. 1453.) using this approach have been most promising; the vacuum arc ion source(I.G. Brown, ``Vacuum Arc Ion Sources'', Rev. Sci. Instrum. 65, 3061 (1994).) uranium ion beam output of mostly U^3+ ions was increased significantly, although the yield of high charge state ions was only a small fraction of the original source current. In our experiments the electron beam will propagate antiparallel to the ion beam so as to provide a radially inward Lorentz force to confine and focus the stripped uranium beam, thus maximizing the electron-ion interactions and increasing the ion beam current density. We expect improved performance over the encouraging earlier^1 results. The motivation for this work(Ady Hershcovitch and Brant Johnson, RHIC/DET Note 17 and AGS/ ADD/Tech. Note No. 416) is the desire to eventually inject fully stripped uranium into the Relativistic Heavy Ion Collider (RHIC).

  19. Design and characterization of the annular cathode high current pulsed electron beam source for circular components

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Wang, Langping; Wang, Xiaofeng

    2016-08-01

    In order to irradiate circular components with high current pulsed electron beam (HCPEB), an annular cathode based on carbon fiber bunches was designed and fabricated. Using an acceleration voltage of 25 kV, the maximum pulsed irradiation current and energy of this annular cathode can reach 7.9 kA and 300 J, respectively. The irradiation current density distribution of the annular cathode HCPEB source measured along the circumferential direction shows that the annular cathode has good emission uniformity. In addition, four 9310 steel substrates fixed uniformly along the circumferential direction of a metal ring substrate were irradiated by this annular cathode HCPEB source. The surface and cross-section morphologies of the irradiated samples were characterized by scanning electron microscopy (SEM). SEM images of the surface reveal that crater and surface undulation have been formed, which hints that the irradiation energy of the HCPEB process is large enough for surface modification of 9310 steel. Meanwhile, SEM cross-section images exhibit that remelted layers with a thickness of about 5.4 μm have been obtained in all samples, which proves that a good practical irradiation uniformity can be achieved by this annular cathode HCPEB source.

  20. Extracting functional components of neural dynamics with Independent Component Analysis and inverse Current Source Density.

    PubMed

    Lęski, Szymon; Kublik, Ewa; Swiejkowski, Daniel A; Wróbel, Andrzej; Wójcik, Daniel K

    2010-12-01

    Local field potentials have good temporal resolution but are blurred due to the slow spatial decay of the electric field. For simultaneous recordings on regular grids one can reconstruct efficiently the current sources (CSD) using the inverse Current Source Density method (iCSD). It is possible to decompose the resultant spatiotemporal information about the current dynamics into functional components using Independent Component Analysis (ICA). We show on test data modeling recordings of evoked potentials on a grid of 4 × 5 × 7 points that meaningful results are obtained with spatial ICA decomposition of reconstructed CSD. The components obtained through decomposition of CSD are better defined and allow easier physiological interpretation than the results of similar analysis of corresponding evoked potentials in the thalamus. We show that spatiotemporal ICA decompositions can perform better for certain types of sources but it does not seem to be the case for the experimental data studied. Having found the appropriate approach to decomposing neural dynamics into functional components we use the technique to study the somatosensory evoked potentials recorded on a grid spanning a large part of the forebrain. We discuss two example components associated with the first waves of activation of the somatosensory thalamus. We show that the proposed method brings up new, more detailed information on the time and spatial location of specific activity conveyed through various parts of the somatosensory thalamus in the rat.

  1. A test of source-surface model predictions of heliospheric current sheet inclination

    NASA Technical Reports Server (NTRS)

    Burton, M. E.; Crooker, N. U.; Siscoe, G. L.; Smith, E. J.

    1994-01-01

    The orientation of the heliospheric current sheet predicted from a source surface model is compared with the orientation determined from minimum-variance analysis of International Sun-Earth Explorer (ISEE) 3 magnetic field data at 1 AU near solar maximum. Of the 37 cases analyzed, 28 have minimum variance normals that lie orthogonal to the predicted Parker spiral direction. For these cases, the correlation coefficient between the predicted and measured inclinations is 0.6. However, for the subset of 14 cases for which transient signatures (either interplanetary shocks or bidirectional electrons) are absent, the agreement in inclinations improves dramatically, with a correlation coefficient of 0.96. These results validate not only the use of the source surface model as a predictor but also the previously questioned usefulness of minimum variance analysis across complex sector boundaries. In addition, the results imply that interplanetary dynamics have little effect on current sheet inclination at 1 AU. The dependence of the correlation on transient occurrence suggests that the leading edge of a coronal mass ejection (CME), where transient signatures are detected, disrupts the heliospheric current sheet but that the sheet re-forms between the trailing legs of the CME. In this way the global structure of the heliosphere, reflected both in the source surface maps and in the interplanetary sector structure, can be maintained even when the CME occurrence rate is high.

  2. Hybrid CMOS SiPIN detectors as astronomical imagers

    NASA Astrophysics Data System (ADS)

    Simms, Lance Michael

    Charge Coupled Devices (CCDs) have dominated optical and x-ray astronomy since their inception in 1969. Only recently, through improvements in design and fabrication methods, have imagers that use Complimentary Metal Oxide Semiconductor (CMOS) technology gained ground on CCDs in scientific imaging. We are now in the midst of an era where astronomers might begin to design optical telescope cameras that employ CMOS imagers. The first three chapters of this dissertation are primarily composed of introductory material. In them, we discuss the potential advantages that CMOS imagers offer over CCDs in astronomical applications. We compare the two technologies in terms of the standard metrics used to evaluate and compare scientific imagers: dark current, read noise, linearity, etc. We also discuss novel features of CMOS devices and the benefits they offer to astronomy. In particular, we focus on a specific kind of hybrid CMOS sensor that uses Silicon PIN photodiodes to detect optical light in order to overcome deficiencies of commercial CMOS sensors. The remaining four chapters focus on a specific type of hybrid CMOS Silicon PIN sensor: the Teledyne Hybrid Visible Silicon PIN Imager (HyViSI). In chapters four and five, results from testing HyViSI detectors in the laboratory and at the Kitt Peak 2.1m telescope are presented. We present our laboratory measurements of the standard detector metrics for a number of HyViSI devices, ranging from 1k×1k to 4k×4k format. We also include a description of the SIDECAR readout circuit that was used to control the detectors. We then show how they performed at the telescope in terms of photometry, astrometry, variability measurement, and telescope focusing and guiding. Lastly, in the final two chapters we present results on detector artifacts such as pixel crosstalk, electronic crosstalk, and image persistence. One form of pixel crosstalk that has not been discussed elsewhere in the literature, which we refer to as Interpixel Charge

  3. Improved PHIP polarization using a precision, low noise, voltage controlled current source.

    PubMed

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  4. Contact CMOS imaging of gaseous oxygen sensor array

    PubMed Central

    Daivasagaya, Daisy S.; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C.; Chodavarapu, Vamsy P.; Bright, Frank V.

    2014-01-01

    We describe a compact luminescent gaseous oxygen (O2) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O2-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)3]2+) encapsulated within sol–gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors. PMID:24493909

  5. Contact CMOS imaging of gaseous oxygen sensor array.

    PubMed

    Daivasagaya, Daisy S; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-10-01

    We describe a compact luminescent gaseous oxygen (O2) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O2-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)3](2+)) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.

  6. Proof of principle study of the use of a CMOS active pixel sensor for proton radiography.

    PubMed

    Seco, Joao; Depauw, Nicolas

    2011-02-01

    Proof of principle study of the use of a CMOS active pixel sensor (APS) in producing proton radiographic images using the proton beam at the Massachusetts General Hospital (MGH). A CMOS APS, previously tested for use in s-ray radiation therapy applications, was used for proton beam radiographic imaging at the MGH. Two different setups were used as a proof of principle that CMOS can be used as proton imaging device: (i) a pen with two metal screws to assess spatial resolution of the CMOS and (ii) a phantom with lung tissue, bone tissue, and water to assess tissue contrast of the CMOS. The sensor was then traversed by a double scattered monoenergetic proton beam at 117 MeV, and the energy deposition inside the detector was recorded to assess its energy response. Conventional x-ray images with similar setup at voltages of 70 kVp and proton images using commercial Gafchromic EBT 2 and Kodak X-Omat V films were also taken for comparison purposes. Images were successfully acquired and compared to x-ray kVp and proton EBT2/X-Omat film images. The spatial resolution of the CMOS detector image is subjectively comparable to the EBT2 and Kodak X-Omat V film images obtained at the same object-detector distance. X-rays have apparent higher spatial resolution than the CMOS. However, further studies with different commercial films using proton beam irradiation demonstrate that the distance of the detector to the object is important to the amount of proton scatter contributing to the proton image. Proton images obtained with films at different distances from the source indicate that proton scatter significantly affects the CMOS image quality. Proton radiographic images were successfully acquired at MGH using a CMOS active pixel sensor detector. The CMOS demonstrated spatial resolution subjectively comparable to films at the same object-detector distance. Further work will be done in order to establish the spatial and energy resolution of the CMOS detector for protons. The

  7. Proof of principle study of the use of a CMOS active pixel sensor for proton radiography

    SciTech Connect

    Seco, Joao; Depauw, Nicolas

    2011-02-15

    Purpose: Proof of principle study of the use of a CMOS active pixel sensor (APS) in producing proton radiographic images using the proton beam at the Massachusetts General Hospital (MGH). Methods: A CMOS APS, previously tested for use in s-ray radiation therapy applications, was used for proton beam radiographic imaging at the MGH. Two different setups were used as a proof of principle that CMOS can be used as proton imaging device: (i) a pen with two metal screws to assess spatial resolution of the CMOS and (ii) a phantom with lung tissue, bone tissue, and water to assess tissue contrast of the CMOS. The sensor was then traversed by a double scattered monoenergetic proton beam at 117 MeV, and the energy deposition inside the detector was recorded to assess its energy response. Conventional x-ray images with similar setup at voltages of 70 kVp and proton images using commercial Gafchromic EBT 2 and Kodak X-Omat V films were also taken for comparison purposes. Results: Images were successfully acquired and compared to x-ray kVp and proton EBT2/X-Omat film images. The spatial resolution of the CMOS detector image is subjectively comparable to the EBT2 and Kodak X-Omat V film images obtained at the same object-detector distance. X-rays have apparent higher spatial resolution than the CMOS. However, further studies with different commercial films using proton beam irradiation demonstrate that the distance of the detector to the object is important to the amount of proton scatter contributing to the proton image. Proton images obtained with films at different distances from the source indicate that proton scatter significantly affects the CMOS image quality. Conclusion: Proton radiographic images were successfully acquired at MGH using a CMOS active pixel sensor detector. The CMOS demonstrated spatial resolution subjectively comparable to films at the same object-detector distance. Further work will be done in order to establish the spatial and energy resolution of the

  8. A high speed, low power consumption LVDS interface for CMOS pixel sensors

    NASA Astrophysics Data System (ADS)

    Shi, Zhan; Tang, Zhenan; Tian, Yong; Pham, Hung; Valin, Isabelle; Jaaskelainen, Kimmo

    2015-01-01

    The use of CMOS Pixel Sensors (CPSs) offers a promising approach to the design of vertex detectors in High Energy Physics (HEP) experiments. As the CPS equipping the upgraded Solenoidal Tracker at RHIC (STAR) pixel detector, ULTIMATE perfectly illustrates the potential of CPSs for HEP applications. However, further development of CPSs with respect to readout speed is required to fulfill the readout time requirement of the next generation HEP detectors, such as the upgrade of A Large Ion Collider Experiment (ALICE) Inner Tracking System (ITS), the International Linear Collider (ILC), and the Compressed Baryonic Matter (CBM) vertex detectors. One actual limitation of CPSs is related to the speed of the Low-Voltage Differential Signaling (LVDS) circuitry implementing the interface between the sensor and the Data Acquisition (DAQ) system. To improve the transmission rate while keeping the power consumption at a low level, a source termination technique and a special current comparator were adopted for the LVDS driver and receiver, respectively. Moreover, hardening techniques are used. The circuitry was designed and submitted for fabrication in a 0.18-μm CMOS Image Sensor (CIS) process at the end of 2011. The test results indicated that the LVDS driver and receiver can operate properly at the data rate of 1.2 Gb/s with power consumption of 19.6 mW.

  9. A Wideband Noise-canceling CMOS LNA Using Cross-coupled Feedback and Bulk Effect

    NASA Astrophysics Data System (ADS)

    Guo, Benqing; Yang, Guoning; An, Shiquan

    2014-05-01

    An improved wideband common-gate (CG) and common-source (CS) CMOS LNA with noise cancellation is proposed. The cross-coupled feedback between the CG input transistor and the cascode transistor of CS input stage is used to increase the input transconductance of the LNA. And the bulk effect of CS input transistors is utilized to enhance gm-boosting coefficient. Thus, comparable gain and noise are achieved by reduced bias currents of the LNA while the resulted additional NF degradation is negligible. Fabricated in a 0.13 μm RF CMOS process, the LNA achieves a flat voltage gain of 18 dB, an NF of 2.7~3.2 dB, and an IIP3 of -4.5~-7.4 dBm over a 3 dB bandwidth of 0.1~4.4 GHz. It consumes only 4.1 mA from a 1 V supply and occupies an area of 520 × 490 um2. In contrast to those of reported wideband LNAs, the proposed LNA has the merit of lower power consumption and lower supply voltage.

  10. CMOS Hybrid Pixel Detectors for Scientific, Industrial and Medical Applications

    NASA Astrophysics Data System (ADS)

    Broennimann, Christian

    2009-03-01

    Crystallography is the principal technique for determining macromolecular structures at atomic resolution and uses advantageously the high intensity of 3rd generation synchrotron X-ray sources . Macromolecular crystallography experiments benefit from excellent beamline equipment, recent software advances and modern X-ray detectors. However, the latter do not take full advantage of the brightness of modern synchrotron sources. CMOS Hybrid pixel array detectors, originally developed for high energy physics experiments, meet these requirements. X-rays are recorded in single photon counting mode and data thus are stored digitally at the earliest possible stage. This architecture leads to several advantages over current detectors: No detector noise is added to the signal. Readout time is reduced to a few milliseconds. The counting rates are matched to beam intensities at protein crystallography beamlines at 3rd generation synchrotrons. The detector is not sensitive to X-rays during readout; therefore no mechanical shutter is required. The detector has a very sharp point spread function (PSF) of one pixel, which allows better resolution of adjacent reflections. Low energy X-rays can be suppressed by the comparator At the Paul Scherrer Institute (PSI) in Switzerland the first and largest array based on this technology was constructed: The Pilatus 6M detector. The detector covers an area of 43.1 x 44.8 cm2 , has 6 million pixels and is read out noise free in 3.7 ms. Since June 2007 the detector is in routine operation at the beamline 6S of the Swiss Light Source (SLS). The company DETCRIS Ltd, has licensed the technology from PSI and is commercially offering the PILATUS detectors. Examples of the wide application range of the detectors will be shown.

  11. Eight channel transmit array volume coil using on-coil radiofrequency current sources

    PubMed Central

    Kurpad, Krishna N.; Boskamp, Eddy B.

    2014-01-01

    Background At imaging frequencies associated with high-field MRI, the combined effects of increased load-coil interaction and shortened wavelength results in degradation of circular polarization and B1 field homogeneity in the imaging volume. Radio frequency (RF) shimming is known to mitigate the problem of B1 field inhomogeneity. Transmit arrays with well decoupled transmitting elements enable accurate B1 field pattern control using simple, non-iterative algorithms. Methods An eight channel transmit array was constructed. Each channel consisted of a transmitting element driven by a dedicated on-coil RF current source. The coil current distributions of characteristic transverse electromagnetic (TEM) coil resonant modes were non-iteratively set up on each transmitting element and 3T MRI images of a mineral oil phantom were obtained. Results B1 field patterns of several linear and quadrature TEM coil resonant modes that typically occur at different resonant frequencies were replicated at 128 MHz without having to retune the transmit array. The generated B1 field patterns agreed well with simulation in most cases. Conclusions Independent control of current amplitude and phase on each transmitting element was demonstrated. The transmit array with on-coil RF current sources enables B1 field shimming in a simple and predictable manner. PMID:24834418

  12. Development of a high average current polarized electron source with long cathode operational lifetime

    SciTech Connect

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  13. Eight channel transmit array volume coil using on-coil radiofrequency current sources.

    PubMed

    Kurpad, Krishna N; Boskamp, Eddy B; Wright, Steven M

    2014-04-01

    At imaging frequencies associated with high-field MRI, the combined effects of increased load-coil interaction and shortened wavelength results in degradation of circular polarization and B1 field homogeneity in the imaging volume. Radio frequency (RF) shimming is known to mitigate the problem of B1 field inhomogeneity. Transmit arrays with well decoupled transmitting elements enable accurate B1 field pattern control using simple, non-iterative algorithms. An eight channel transmit array was constructed. Each channel consisted of a transmitting element driven by a dedicated on-coil RF current source. The coil current distributions of characteristic transverse electromagnetic (TEM) coil resonant modes were non-iteratively set up on each transmitting element and 3T MRI images of a mineral oil phantom were obtained. B1 field patterns of several linear and quadrature TEM coil resonant modes that typically occur at different resonant frequencies were replicated at 128 MHz without having to retune the transmit array. The generated B1 field patterns agreed well with simulation in most cases. Independent control of current amplitude and phase on each transmitting element was demonstrated. The transmit array with on-coil RF current sources enables B1 field shimming in a simple and predictable manner.

  14. A Multipurpose CMOS Platform for Nanosensing

    PubMed Central

    Bonanno, Alberto; Sanginario, Alessandro; Marasso, Simone L.; Miccoli, Beatrice; Bejtka, Katarzyna; Benetto, Simone; Demarchi, Danilo

    2016-01-01

    This paper presents a customizable sensing system based on functionalized nanowires (NWs) assembled onto complementary metal oxide semiconductor (CMOS) technology. The Micro-for-Nano (M4N) chip integrates on top of the electronics an array of aluminum microelectrodes covered with gold by means of a customized electroless plating process. The NW assembly process is driven by an array of on-chip dielectrophoresis (DEP) generators, enabling a custom layout of different nanosensors on the same microelectrode array. The electrical properties of each assembled NW are singularly sensed through an in situ CMOS read-out circuit (ROC) that guarantees a low noise and reliable measurement. The M4N chip is directly connected to an external microcontroller for configuration and data processing. The processed data are then redirected to a workstation for real-time data visualization and storage during sensing experiments. As proof of concept, ZnO nanowires have been integrated onto the M4N chip to validate the approach that enables different kind of sensing experiments. The device has been then irradiated by an external UV source with adjustable power to measure the ZnO sensitivity to UV-light exposure. A maximum variation of about 80% of the ZnO-NW resistance has been detected by the M4N system when the assembled 5 μm × 500 nm single ZnO-NW is exposed to an estimated incident radiant UV-light flux in the range of 1 nW–229 nW. The performed experiments prove the efficiency of the platform conceived for exploiting any kind of material that can change its capacitance and/or resistance due to an external stimulus. PMID:27916911

  15. A Multipurpose CMOS Platform for Nanosensing.

    PubMed

    Bonanno, Alberto; Sanginario, Alessandro; Marasso, Simone L; Miccoli, Beatrice; Bejtka, Katarzyna; Benetto, Simone; Demarchi, Danilo

    2016-11-30

    This paper presents a customizable sensing system based on functionalized nanowires (NWs) assembled onto complementary metal oxide semiconductor (CMOS) technology. The Micro-for-Nano (M4N) chip integrates on top of the electronics an array of aluminum microelectrodes covered with gold by means of a customized electroless plating process. The NW assembly process is driven by an array of on-chip dielectrophoresis (DEP) generators, enabling a custom layout of different nanosensors on the same microelectrode array. The electrical properties of each assembled NW are singularly sensed through an in situ CMOS read-out circuit (ROC) that guarantees a low noise and reliable measurement. The M4N chip is directly connected to an external microcontroller for configuration and data processing. The processed data are then redirected to a workstation for real-time data visualization and storage during sensing experiments. As proof of concept, ZnO nanowires have been integrated onto the M4N chip to validate the approach that enables different kind of sensing experiments. The device has been then irradiated by an external UV source with adjustable power to measure the ZnO sensitivity to UV-light exposure. A maximum variation of about 80% of the ZnO-NW resistance has been detected by the M4N system when the assembled 5 μ m × 500 nm single ZnO-NW is exposed to an estimated incident radiant UV-light flux in the range of 1 nW-229 nW. The performed experiments prove the efficiency of the platform conceived for exploiting any kind of material that can change its capacitance and/or resistance due to an external stimulus.

  16. Characterization and development of an event-driven hybrid CMOS x-ray detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher

    2015-06-01

    Hybrid CMOS detectors (HCD) have provided great benefit to the infrared and optical fields of astronomy, and they are poised to do the same for X-ray astronomy. Infrared HCDs have already flown on the Hubble Space Telescope and the Wide-Field Infrared Survey Explorer (WISE) mission and are slated to fly on the James Webb Space Telescope (JWST). Hybrid CMOS X-ray detectors offer low susceptibility to radiation damage, low power consumption, and fast readout time to avoid pile-up. The fast readout time is necessary for future high throughput X-ray missions. The Speedster-EXD X-ray HCD presented in this dissertation offers new in-pixel features and reduces known noise sources seen on previous generation HCDs. The Speedster-EXD detector makes a great step forward in the development of these detectors for future space missions. This dissertation begins with an overview of future X-ray space mission concepts and their detector requirements. The background on the physics of semiconductor devices and an explanation of the detection of X-rays with these devices will be discussed followed by a discussion on CCDs and CMOS detectors. Next, hybrid CMOS X-ray detectors will be explained including their advantages and disadvantages. The Speedster-EXD detector and its new features will be outlined including its ability to only read out pixels which contain X-ray events. Test stand design and construction for the Speedster-EXD detector is outlined and the characterization of each parameter on two Speedster-EXD detectors is detailed including read noise, dark current, interpixel capacitance crosstalk (IPC), and energy resolution. Gain variation is also characterized, and a Monte Carlo simulation of its impact on energy resolution is described. This analysis shows that its effect can be successfully nullified with proper calibration, which would be important for a flight mission. Appendix B contains a study of the extreme tidal disruption event, Swift J1644+57, to search for

  17. CMOS Integrated Single Electron Transistor Electrometry (CMOS-SET) circuit design for nanosecond quantum-bit read-out.

    SciTech Connect

    Gurrieri, Thomas M.; Lilly, Michael Patrick; Carroll, Malcolm S.; Levy, James E.

    2008-08-01

    Novel single electron transistor (SET) read-out circuit designs are described. The circuits use a silicon SET interfaced to a CMOS voltage mode or current mode comparator to obtain a digital read-out of the state of the qubit. The design assumes standard submicron (0.35 um) CMOS SOI technology using room temperature SPICE models. Implications and uncertainties related to the temperature scaling of these models to 100mK operation are discussed. Using this technology, the simulations predict a read-out operation speed of approximately Ins and a power dissipation per cell as low as 2nW for single-shot read-out, which is a significant advantage over currently used radio frequency SET (RF-SET) approaches.

  18. JPL CMOS Active Pixel Sensor Technology

    NASA Technical Reports Server (NTRS)

    Fossum, E. R.

    1995-01-01

    This paper will present the JPL-developed complementary metal- oxide-semiconductor (CMOS) active pixel sensor (APS) technology. The CMOS APS has achieved performance comparable to charge coupled devices, yet features ultra low power operation, random access readout, on-chip timing and control, and on-chip analog to digital conversion. Previously published open literature will be reviewed.

  19. A back-illuminated megapixel CMOS image sensor

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Cunningham, Thomas; Nikzad, Shouleh; Hoenk, Michael; Jones, Todd; Wrigley, Chris; Hancock, Bruce

    2005-01-01

    In this paper, we present the test and characterization results for a back-illuminated megapixel CMOS imager. The imager pixel consists of a standard junction photodiode coupled to a three transistor-per-pixel switched source-follower readout [1]. The imager also consists of integrated timing and control and bias generation circuits, and provides analog output. The analog column-scan circuits were implemented in such a way that the imager could be configured to run in off-chip correlated double-sampling (CDS) mode. The imager was originally designed for normal front-illuminated operation, and was fabricated in a commercially available 0.5 pn triple-metal CMOS-imager compatible process. For backside illumination, the imager was thinned by etching away the substrate was etched away in a post-fabrication processing step.

  20. Simulation of a distributed current source in a linear format CFA

    NASA Astrophysics Data System (ADS)

    Pearlman, Marcus; Browning, Jim

    2015-11-01

    A fundamental limit on Crossed-Field Amplifiers (CFA) gain is beam to RF power ratio. With too much beam power, the RF signal on the slow wave circuit is ``swamped.'' It is proposed here that a controllable, distributed cathode source can be used to tailor current injection and optimize gain. In this work a linear format CFA with a meander line slow wave circuit is tested experimentally and numerically using Vsim. Simulations of the original design, which operates at 900 MHz, shows < 1dB gain at beam currents >100 mA. This beam current is higher than the capabilities of the Field Emitter Array cathodes available to the group; therefore no experimental gain was observed. To be able to compare simulation to experiment, the CFA model under study was changed to the experiment used at Northeastern University in 1991, which also uses a meander line circuit and an injected beam configuration. Direct comparisons between the simulation and this experiment are performed to validate the model. Additional simulations study the effect of different current distributions on gain, bandwidth, and efficiency. Practical considerations such as how to control the energy of the beam separately from the sole potential in order to minimize lost current to sole are also examined. This research was supported by the Air Force Office of Scientific Research and the department of Electrical and Computer Engineering at Boise State University.

  1. CMOS foveal image sensor chip

    NASA Technical Reports Server (NTRS)

    Bandera, Cesar (Inventor); Scott, Peter (Inventor); Sridhar, Ramalingam (Inventor); Xia, Shu (Inventor)

    2002-01-01

    A foveal image sensor integrated circuit comprising a plurality of CMOS active pixel sensors arranged both within and about a central fovea region of the chip. The pixels in the central fovea region have a smaller size than the pixels arranged in peripheral rings about the central region. A new photocharge normalization scheme and associated circuitry normalizes the output signals from the different size pixels in the array. The pixels are assembled into a multi-resolution rectilinear foveal image sensor chip using a novel access scheme to reduce the number of analog RAM cells needed. Localized spatial resolution declines monotonically with offset from the imager's optical axis, analogous to biological foveal vision.

  2. Nanosecond monolithic CMOS readout cell

    DOEpatents

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  3. The neutral current sheet and its radiation pairs of side sources in coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Ji, Shu-Chen

    Using the data observed with the soft X-ray telescope, hard X-ray telescope aboard on Yohkoh and the Nobeyama Radioheliograph on 1998 April 23, a comprehensive study on soft X-ray coronal mass ejection (SXRCME) and radio Type IV burst is carried out and some significant results are obtained as follows: A magnetic capacity belt (MCB) between two magnetic dipole sources (MDSs) was found and there were only a few activitation sources (ASs). During the MCB changed into a magnetic energy belt (MEB) by the ASs, activating energy and shining material both concentrated to the neutral current sheet (NCS) in the course of its formation. When two MDSs were put through by the MEB, the NCS formed and the SXRCME occurred. The matter ejected not only from the NCS, but also from the whole MEB. The expanding loop of the SXRCME had two foot points, both were just two MDSs. The head of the expanding loop always tended to the foot point of the weak source, because it was equilibrium point of magnetic pressures coming from two foot points. For this reason, its locus was neutral line. From this, the neutral line can also determine the position of NCS. Finally, the radiation pairs of side sources of NCS on the MEB are found.

  4. Revealing sources and chemical identity of iron ligands across the California Current System

    NASA Astrophysics Data System (ADS)

    Boiteau, R.; Repeta, D.; Fitzsimmons, J. N.; Parker, C.; Twining, B. S.; Baines, S.

    2016-02-01

    The California Current System is one of the most productive regions of the ocean, fueled by the upwelling of nutrient rich water. Differences in the supply of micronutrient iron to surface waters along the coast lead to a mosaic of iron-replete and iron-limited conditions across the region, affecting primary production and community composition. Most of the iron in this region is supplied by upwelling of iron from the benthic boundary layer that is complexed by strong organic ligands. However, the source, identity, and bioavailability of these ligands are unknown. Here, we used novel hyphenated chromatography mass spectrometry approaches to structurally characterize organic ligands across the region. With these methods, iron ligands are detected with liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC-ICPMS), and then their mass and fragmentation spectra are determined by high resolution electrospray ionization mass spectrometry (LC-ESIMS). Iron isotopic exchange was used to compare the relative binding strengths of different ligands. Our survey revealed a broad range of ligands from multiple sources. Benthic boundary layers and anoxic sediments were sources of structurally amorphous weak ligands, likely organic degradation products, as well as siderophores, strong iron binding molecules that facilitate iron acquisition. In the euphotic zone, marine microbes and zooplankton grazing produced a wide distribution of other compounds that included known and novel siderophores. This work demonstrates that the chemical nature of ligands from different sources varies substantially and has important implications for iron biogeochemical cycling and availability to members of the microbial community.

  5. On the development of a 15 mA direct current H - multicusp source

    NASA Astrophysics Data System (ADS)

    Kuo, T.; Yuan, D.; Jayamanna, K.; McDonald, M.; Baartman, R.; Schmor, P.; Dutto, G.

    1996-03-01

    A 15 mA dc H- multicusp source has been developed for injection into a TR30 cyclotron. This source is also used with a 900 kV tandem accelerator to obtain 10 mA protons at 1.8 MeV. The program is an extension of the 5-7 mA dc H- cusp source developed at TRIUMF during 1989-1990. Major efforts include the search for the optimal filament materials, shape, and location; comparison of cusp line confinement and magnetic filtering of electrons at the extraction region; optimization of extraction lense configuration; and upgrading of vacuum and power systems capability. The source is noncesiated and the maximum arc power available is only 5 kW. After the H- beams pass through an electron suppression grid and a 20 mm collimator, we obtained 15 mA with 0.66 π mm mrad 4 rms normalized emittance. At this output the e/H ratio was about 4. The best normalized emittance occurs around 5-7 mA, having a value of 0.37 π mm mrad. Further development in the near future is planned using cesium and multiple apertures in the hope of increasing dc H- currents to 30 mA while holding the normalized emittance below 0.75 π mm mrad.

  6. Design of a low voltage, high current extraction system for the ITER Ion Source

    SciTech Connect

    Agostinetti, P.; Antoni, V.; Marcuzzi, D.; Pilan, N.; Rigato, W.; Serianni, G.; Sonato, P.; Veltri, P.; Zaccaria, P.; Cavenago, M.; Petrenko, S.; Esch, H. P. L. de

    2009-03-12

    A Test Facility is planned to be built in Padova to assemble and test the Neutral Beam Injector for ITER. In the same Test Facility the Ion Source will be tested in a dedicated facility planned to operate in parallel to the main 1 MV facility. Purpose of the full size Ion Source is to optimize the Ion Source performance by maximizing the extracted negative ion current density and its spatial uniformity and by minimizing the ratio of co-extracted electrons. In this contribution the design of the extractor and accelerator grids for a 100 kV, 60 A system is presented. The trajectories of the negative ions, calculated with the SLACCAD code [1], have been benchmarked by a new 2D code (BYPO [2]) which solves in a self consistent way the electric fields in presence of electric charge and magnetic fields. The energy flux intercepted by the grids is estimated by using the Montecarlo code EAMCC [3] and the grids designed according to the constraints set by the permanent magnets and by the cooling channels. The interaction of backstreaming ions due to the ionization process with the grids and the Ion Source backplate is investigated and its impact on the project and performance discussed.

  7. Design of a low voltage, high current extraction system for the ITER Ion Source

    NASA Astrophysics Data System (ADS)

    Agostinetti, P.; Antoni, V.; Cavenago, M.; de Esch, H. P. L.; Fubiani, G.; Marcuzzi, D.; Petrenko, S.; Pilan, N.; Rigato, W.; Serianni, G.; Singh, M.; Sonato, P.; Veltri, P.; Zaccaria, P.

    2009-03-01

    A Test Facility is planned to be built in Padova to assemble and test the Neutral Beam Injector for ITER. In the same Test Facility the Ion Source will be tested in a dedicated facility planned to operate in parallel to the main 1 MV facility. Purpose of the full size Ion Source is to optimize the Ion Source performance by maximizing the extracted negative ion current density and its spatial uniformity and by minimizing the ratio of co-extracted electrons. In this contribution the design of the extractor and accelerator grids for a 100 kV, 60 A system is presented. The trajectories of the negative ions, calculated with the SLACCAD code [1], have been benchmarked by a new 2D code (BYPO [2]) which solves in a self consistent way the electric fields in presence of electric charge and magnetic fields. The energy flux intercepted by the grids is estimated by using the Montecarlo code EAMCC [3] and the grids designed according to the constraints set by the permanent magnets and by the cooling channels. The interaction of backstreaming ions due to the ionization process with the grids and the Ion Source backplate is investigated and its impact on the project and performance discussed.

  8. Hybrid CMOS/Molecular Integrated Circuits

    NASA Astrophysics Data System (ADS)

    Stan, M. R.; Rose, G. S.; Ziegler, M. M.

    CMOS silicon technologies are likely to run out of steam in the next 10-15 years despite revolutionary advances in the past few decades. Molecular and other nanoscale technologies show significant promise but it is unlikely that they will completely replace CMOS, at least in the near term. This chapter explores opportunities for using CMOS and nanotechnology to enhance and complement each other in hybrid circuits. As an example of such a hybrid CMOS/nano system, a nanoscale programmable logic array (PLA) based on majority logic is described along with its supplemental CMOS circuitry. It is believed that such systems will be able to sustain the historical advances in the semiconductor industry while addressing manufacturability, yield, power, cost, and performance challenges.

  9. Integrated CMOS transceiver for indoor optical wireless links

    NASA Astrophysics Data System (ADS)

    Holburn, David M.; Lalithambika, Vinod A.; Joyner, Valencia M.; Samsudin, Rina J.; Mears, Robert J.

    2001-11-01

    The purpose of this work is to develop integrated CMOS designs for optical transceivers at 1.55um wavelength that both meet the current system specification of 155Mb/s and provide a viable upgrade path to higher bit-rates. We present the design and implementation of an integrated multi-channel CMOS transceiver for use in a cellular 155Mb/s Manchester-coded optical wireless link. The receiver is an angle-diversity design and consists of multiple sectors with relatively small field of view; each driving an individual pre-amplifier channel. An on-chip selector selects signals to be passed to the combiner depending on the signal level and external control signals. The outputs of all the selected channels are combined using a current summing junction, implemented using a transconductance-transimpedance approach. In order to achieve a receiver design that will be robust in the face of process variations, an on-chip circuit is provided to maintain the operating point of the amplifier chain. The design has been optimized to achieve -30dBm sensitivity at a BER of 10-9. The CMOS transmitter circuit is tailored to match the electro-optic response of the resonant cavity LEDs being used. The transmitter driver incorporates current-peaking and charge-extraction circuitry using a novel timing generator, and has been designed to achieve rise and fall times of better than 0.2ns. Considerable effort is being directed towards the development of integrated designs which do not require significant numbers of discrete components. The prototype designs are being realised in a 0.7μm commodity mixed-signal CMOS process by Alcatel Microelectronics. We report results from the first prototype multi-channel demonstrator system and discuss future research directions.

  10. Measurement of Turbulence with Acoustic Doppler Current Profilers - Sources of Error and Laboratory Results

    USGS Publications Warehouse

    Nystrom, E.A.; Oberg, K.A.; Rehmann, C.R.; ,

    2002-01-01

    Acoustic Doppler current profilers (ADCPs) provide a promising method for measuring surface-water turbulence because they can provide data from a large spatial range in a relatively short time with relative ease. Some potential sources of errors in turbulence measurements made with ADCPs include inaccuracy of Doppler-shift measurements, poor temporal and spatial measurement resolution, and inaccuracy of multi-dimensional velocities resolved from one-dimensional velocities measured at separate locations. Results from laboratory measurements of mean velocity and turbulence statistics made with two pulse-coherent ADCPs in 0.87 meters of water are used to illustrate several of inherent sources of error in ADCP turbulence measurements. Results show that processing algorithms and beam configurations have important effects on turbulence measurements. ADCPs can provide reasonable estimates of many turbulence parameters; however, the accuracy of turbulence measurements made with commercially available ADCPs is often poor in comparison to standard measurement techniques.

  11. Single-layer and multilayer mirrors for current and next-generation light sources

    NASA Astrophysics Data System (ADS)

    Störmer, Michael; Horstmann, Christian; Häussler, Dietrich; Spiecker, Erdmann; Siewert, Frank; Scholze, Frank; Hertlein, Frank; Jäger, Wolfgang; Bormann, Rüdiger

    2008-08-01

    Current and next-generation light sources, for instance third generation synchrotron sources, FLASH and the future project X-FEL require single-layer and multilayer mirrors with an active optical length of more than one meter. At the GKSS research centre, a new sputtering system for the deposition of single-layer and multilayers has been installed. This new system is able to manufacture mirrors with a maximum deposition length of 1.5m. In this paper we are going to present the first results of this challenging system. The mirror properties are investigated by means of X-ray reflectometry, transmission electron microscopy and interference microscopy. The performance of the mirrors is analyzed, considering X-ray reflectivity, film thickness, micro-roughness and the uniformity of these properties over the whole deposition length. The results will be discussed and compared with former results.

  12. [Focal evoked potentials in the rabbit visual cortex: density analysis of current sources].

    PubMed

    Supin, A Ia

    1981-01-01

    Focal evoked potentials were elicited in the rabbit visual cortex by punctiform light stimuli and analyzed by the current source density technique. They contained two main components. The first component was generated by local sink at depths form 0.6 to 1.0 mm (layer IV) with 30 ms latency and peak time about 50 ms. The second one was generated by less local sink at depths form 0.2-0.3 to 1.3-1.5 mm (layers III-VI) with peak time 90-100 ms. These two sinks are considered as active and indicating the localization of depolarizing synapses. Passive sources are dissipated around the zone of the active sinks.

  13. High-Voltage-Input Level Translator Using Standard CMOS

    NASA Technical Reports Server (NTRS)

    Yager, Jeremy A.; Mojarradi, Mohammad M.; Vo, Tuan A.; Blalock, Benjamin J.

    2011-01-01

    proposed integrated circuit would translate (1) a pair of input signals having a low differential potential and a possibly high common-mode potential into (2) a pair of output signals having the same low differential potential and a low common-mode potential. As used here, "low" and "high" refer to potentials that are, respectively, below or above the nominal supply potential (3.3 V) at which standard complementary metal oxide/semiconductor (CMOS) integrated circuits are designed to operate. The input common-mode potential could lie between 0 and 10 V; the output common-mode potential would be 2 V. This translation would make it possible to process the pair of signals by use of standard 3.3-V CMOS analog and/or mixed-signal (analog and digital) circuitry on the same integrated-circuit chip. A schematic of the circuit is shown in the figure. Standard 3.3-V CMOS circuitry cannot withstand input potentials greater than about 4 V. However, there are many applications that involve low-differential-potential, high-common-mode-potential input signal pairs and in which standard 3.3-V CMOS circuitry, which is relatively inexpensive, would be the most appropriate circuitry for performing other functions on the integrated-circuit chip that handles the high-potential input signals. Thus, there is a need to combine high-voltage input circuitry with standard low-voltage CMOS circuitry on the same integrated-circuit chip. The proposed circuit would satisfy this need. In the proposed circuit, the input signals would be coupled into both a level-shifting pair and a common-mode-sensing pair of CMOS transistors. The output of the level-shifting pair would be fed as input to a differential pair of transistors. The resulting differential current output would pass through six standoff transistors to be mirrored into an output branch by four heterojunction bipolar transistors. The mirrored differential current would be converted back to potential by a pair of diode-connected transistors

  14. Design and optimization of CMOS LNA with ESD protection for 2.4 GHz WSN application

    NASA Astrophysics Data System (ADS)

    Zhiqun, Li; Liang, Chen; Hao, Zhang

    2011-10-01

    A new optimization method of a source inductive degenerated low noise amplifier (LNA) with electrostatic discharge protection is proposed. It can achieve power-constrained simultaneous noise and input matching. An analysis of the input impedance and the noise parameters is also given. Based on the developed method, a 2.4 GHz LNA for wireless sensor network application is designed and optimized using 0.18-μm RF CMOS technology. The measured results show that the LNA achieves a noise figure of 1.59 dB, a power gain of 14.12 dB, an input 1 dB compression point of -8 dBm and an input third-order intercept point of 1 dBm. The DC current is 4 mA under a supply of 1.8 V.

  15. Reduction of Beam Current Noise in the FNAL Magnetron Ion Source

    SciTech Connect

    Bollinger, D. S.; Karns, P. R.; Tan, C. Y.

    2014-01-01

    The new FNAL Injector Line with a circular dimple magnetron ion source has been operational since December of 2013. Since the new injector came on line there have been variations in the H- beam current flattop observed near the downstream end of the linac. Several different cathode geometries including a hollow cathode suggested by Dudnikov [1] were tried. We expanded on those studies by trying mixtures ranging from 0.25%N, 99.75%H to 3%N, 97%H. The results of these studies in our test stand will be presented in this paper.

  16. Design of the beam shut-off current monitor upgrade for the Advanced Photon Source

    SciTech Connect

    Pietryla, A.; Decker, G.

    2000-05-05

    Plans to eliminate the positron accumulator ring (PAR) from the Advanced Photon Source (APS) injector complex have created the need for a device to limit the allowable beam charge injected into the APS injector synchrotrons. The beam shut-off current monitor (BESOCM) was chosen to provide this function. This new application of the BESOCM provided the opportunity to explore new design philosophies. Two design goals were to de-emphasize reliance on external signals and to become insensitive to timing variations. Both of these goals were accomplished by deriving the trigger directly from the beam. This paper will discuss the features of the new BESOCM design and present data demonstrating its function.

  17. Sensitivity optimization of active filters containing current conveyors and controlled sources

    NASA Astrophysics Data System (ADS)

    Dunning-Davies, J.; Stephenson, F. W.

    1980-03-01

    Employing a technique associated with optimization problems, a minimum sensitivity solution is obtained for a third-order active filter containing a current conveyor. This solution is given in terms of the time constants for the circuit. Further investigation yields a solution in terms of the resistors and capacitors which, as well as being one of minimum sensitivity, is such that the resistor sum and spread and capacitor sum and spread are all small. Similar results are presented for a third-order active filter containing a controlled source.

  18. Reduction of beam current noise in the FNAL magnetron ion source

    SciTech Connect

    Bollinger, D. S. Karns, P. R. Tan, C. Y.

    2015-04-08

    The new FNAL Injector Line with a circular dimple magnetron ion source has been operational since December of 2012. Since the new injector came on line there have been variations in the H- beam current flattop observed near the downstream end of the Linac. Several different cathode geometries including a hollow cathode suggested by Dudnikov [1] were tried. Previous studies also showed that different mixtures of hydrogen and nitrogen had an effect on beam current noise [2]. We expanded on those studies by trying mixtures ranging from (0.25% nitrogen, 99.75% hydrogen) to (3% nitrogen, 97% hydrogen). The results of these studies in our test stand will be presented in this paper.

  19. MEANDER-LINE CURRENT STRUCTURE DEVELOPMENT FOR SPALLATION NEUTRON SOURCE FAST CHOPPER

    SciTech Connect

    S. KURRENOY; J. POWER

    2000-10-01

    A new current structure for the fast traveling-wave 2.5-MeV beam chopper in the front end of the Spallation Neutron Source (SNS) has been suggested in [1]. The structure is based on the meander-folded notched stripline with dielectric supports and separators. Its design has been optimized using electromagnetic 3-D modeling with the MAFIA code package to provide rise and fall times in the range of 1 to 2 ns. A full-length (50 cm) prototype has been manufactured, and its preliminary measurements showed a good agreement with the calculations. Detailed measurements results and their comparison with simulations are presented. The latest front-end design requires a shorter, 35-cm chopper with a higher pulse voltage. Its meander-line current structure, based on the same principles, has also been optimized with MAFIA.

  20. Reprint of: High current liquid metal ion source using porous tungsten multiemitters.

    PubMed

    Tajmar, M; Vasiljevich, I; Grienauer, W

    2011-05-01

    We recently developed an indium Liquid-Metal-Ion-Source that can emit currents from sub-μA up to several mA. It is based on a porous tungsten crown structure with 28 individual emitters, which is manufactured using Micro-Powder Injection Molding (μPIM) and electrochemical etching. The emitter combines the advantages of internal capillary feeding with excellent emission properties due to micron-size tips. Significant progress was made on the homogeneity of the emission over its current-voltage characteristic as well as on investigating its long-term stability. This LMIS seems very suitable for space propulsion as well as for micro/nano manufacturing applications with greatly increased milling/drilling speeds. This paper summarizes the latest developments on our porous multiemitters with respect to manufacturing, emission properties and long-term testing.

  1. Simulation-based validation for four- dimensional multi-channel ultrasound current source density imaging.

    PubMed

    Wang, Zhaohui; Witte, Russell S

    2014-03-01

    Ultrasound current source density imaging (UCSDI), which has application to the heart and brain, exploits the acoustoelectric (AE) effect and Ohm's law to detect and map an electrical current distribution. In this study, we describe 4-D UCSDI simulations of a dipole field for comparison and validation with bench-top experiments. The simulations consider the properties of the ultrasound pulse as it passes through a conductive medium, the electric field of the injected dipole, and the lead field of the detectors. In the simulation, the lead fields of detectors and electric field of the dipole were calculated by the finite element (FE) method, and the convolution and correlation in the computation of the detected AE voltage signal were accelerated using 3-D fast Fourier transforms. In the bench-top experiment, an electric dipole was produced in a bath of 0.9% NaCl solution containing two electrodes, which injected an ac pulse (200 Hz, 3 cycles) ranging from 0 to 140 mA. Stimulating and recording electrodes were placed in a custom electrode chamber made on a rapid prototype printer. Each electrode could be positioned anywhere on an x-y grid (5 mm spacing) and individually adjusted in the depth direction for precise control of the geometry of the current sources and detecting electrodes. A 1-MHz ultrasound beam was pulsed and focused through a plastic film to modulate the current distribution inside the saline-filled tank. AE signals were simultaneously detected at a sampling frequency of 15 MHz on multiple recording electrodes. A single recording electrode is sufficient to form volume images of the current flow and electric potentials. The AE potential is sensitive to the distance from the dipole, but is less sensitive to the angle between the detector and the dipole. Multi-channel UCSDI potentially improves 4-D mapping of bioelectric sources in the body at high spatial resolution, which is especially important for diagnosing and guiding treatment of cardiac and

  2. Simulation-Based Validation for Four-Dimensional Multi-Channel Ultrasound Current Source Density Imaging

    PubMed Central

    Wang, Zhaohui; Witte, Russell S.

    2015-01-01

    Ultrasound current source density imaging (UCSDI), which has application to the heart and brain, exploits the acoustoelectric (AE) effect and Ohm's law to detect and map an electrical current distribution. In this study, we describe 4-D UCSDI simulations of a dipole field for comparison and validation with bench-top experiments. The simulations consider the properties of the ultrasound pulse as it passes through a conductive medium, the electric field of the injected dipole, and the lead field of the detectors. In the simulation, the lead fields of detectors and electric field of the dipole were calculated by the finite element (FE) method, and the convolution and correlation in the computation of the detected AE voltage signal were accelerated using 3-D fast Fourier transforms. In the bench-top experiment, an electric dipole was produced in a bath of 0.9% NaCl solution containing two electrodes, which injected an ac pulse (200 Hz, 3 cycles) ranging from 0 to 140 mA. Stimulating and recording electrodes were placed in a custom electrode chamber made on a rapid prototype printer. Each electrode could be positioned anywhere on an x-y grid (5 mm spacing) and individually adjusted in the depth direction for precise control of the geometry of the current sources and detecting electrodes. A 1-MHz ultrasound beam was pulsed and focused through a plastic film to modulate the current distribution inside the saline-filled tank. AE signals were simultaneously detected at a sampling frequency of 15 MHz on multiple recording electrodes. A single recording electrode is sufficient to form volume images of the current flow and electric potentials. The AE potential is sensitive to the distance from the dipole, but is less sensitive to the angle between the detector and the dipole. Multi-channel UCSDI potentially improves 4-D mapping of bioelectric sources in the body at high spatial resolution, which is especially important for diagnosing and guiding treatment of cardiac and

  3. Current status of new SAGE project with 51Cr neutrino source

    NASA Astrophysics Data System (ADS)

    Gavrin, V.; Cleveland, B.; Danshin, S.; Elliott, S.; Gorbachev, V.; Ibragimova, T.; Kalikhov, A.; Knodel, T.; Kozlova, Yu.; Malyshkin, Yu.; Matveev, V.; Mirmov, I.; Nico, J.; Robertson, R. G. H.; Shikhin, A.; Sinclair, D.; Veretenkin, E.; Wilkerson, J.

    2015-03-01

    A very short-baseline neutrino oscillation experiment with an intense 51Cr neutrino source is currently under construction at the Baksan Neutrino Observatory of the Institute for Nuclear Research RAS (BNO). The experiment, which is based on the existing SAGE experiment, will use an upgraded Gallium-Germanium Neutrino Telescope (GGNT) and an artificial 51Cr neutrino source with activity ˜3 MCi to search for transitions of active neutrinos to sterile states with Δ m 2 ˜1 eV2. The neutrino source will be placed in the center of a liquid Ga metal target that is divided into two concentric zones, internal and external. The average path length of neutrinos in each zone will be the same and the neutrino capture rate will be measured separately in each zone. The oscillation signature, which comes from the ratio of events in the near and far gallium volumes, will be largely free of systematic errors, such as may occur from cross section and source strength uncertainties, and will provide a clean signal of electron neutrino disappearance into a sterile state at baselines of about 0.6 and 2.0 m. The sensitivity to the disappearance of electron neutrinos is expected to be a few percent. Construction of this set of new facilities, including a two-zone tank for irradiation of 50 tons of Ga metal with the intense 51Cr source, as well as additional modules of the GGNT counting and extraction systems, is close to completion. To check the new facilities they will first be used for SAGE solar neutrino measurements.

  4. Changes of cerebral current source by audiovisual erotic stimuli in premature ejaculation patients.

    PubMed

    Hyun, Jae-Seog; Kam, Sung-Chul; Kwon, Oh-Young

    2008-06-01

    Premature ejaculation (PE) is one of the most common forms of male sexual dysfunction. The mechanisms of PE remain poorly understood, despite its high prevalence. To investigate the pathophysiology and causes of PE in the central nervous system, we tried to observe the changes in brain current source distribution by audiovisual induction of sexual arousal. Electroencephalograpies were recorded in patients with PE (45.0 +/- 10.3 years old, N = 18) and in controls (45.6 +/- 9.8 years old, N = 18) during four 10-minute segments of resting, watching a music video excerpt, resting, and watching an erotic video excerpt. Five artifact-free 5-second segments were used to obtain cross-spectral low-resolution brain electromagnetic tomography (LORETA) images. Statistical nonparametric maps (SnPM) were obtained to detect the current density changes of six frequency bands between the erotic video session and the music video session in each group. Comparisons were also made between the two groups in the erotic video session. In the SnPM of each spectrum in patients with PE, the current source density of the alpha band was significantly reduced in the right precentral gyrus, the right insula, and both superior parietal lobules (P < 0.01). Comparing the two groups in the erotic video session, the current densities of the beta-2 and -3 bands in the PE group were significantly decreased in the right parahippocampal gyrus and left middle temporal gyrus (P < 0.01). Neuronal activity in the right precental gyrus, the right insula, both the superior parietal lobule, the right parahippocampal gyrus, and the left middle temporal gyrus may be decreased in PE patients upon sexual arousal. Further studies are needed to evaluate the meaning of decreased neuronal activities in PE patients.

  5. Fundamental performance differences between CMOS and CCD imagers: Part II

    NASA Astrophysics Data System (ADS)

    Janesick, James; Andrews, James; Tower, John; Grygon, Mark; Elliott, Tom; Cheng, John; Lesser, Michael; Pinter, Jeff

    2007-09-01

    A new class of CMOS imagers that compete with scientific CCDs is presented. The sensors are based on deep depletion backside illuminated technology to achieve high near infrared quantum efficiency and low pixel cross-talk. The imagers deliver very low read noise suitable for single photon counting - Fano-noise limited soft x-ray applications. Digital correlated double sampling signal processing necessary to achieve low read noise performance is analyzed and demonstrated for CMOS use. Detailed experimental data products generated by different pixel architectures (notably 3TPPD, 5TPPD and 6TPG designs) are presented including read noise, charge capacity, dynamic range, quantum efficiency, charge collection and transfer efficiency and dark current generation. Radiation damage data taken for the imagers is also reported.

  6. A CMOS silicon spin qubit

    NASA Astrophysics Data System (ADS)

    Maurand, R.; Jehl, X.; Kotekar-Patil, D.; Corna, A.; Bohuslavskyi, H.; Laviéville, R.; Hutin, L.; Barraud, S.; Vinet, M.; Sanquer, M.; de Franceschi, S.

    2016-11-01

    Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform.

  7. A CMOS silicon spin qubit

    PubMed Central

    Maurand, R.; Jehl, X.; Kotekar-Patil, D.; Corna, A.; Bohuslavskyi, H.; Laviéville, R.; Hutin, L.; Barraud, S.; Vinet, M.; Sanquer, M.; De Franceschi, S.

    2016-01-01

    Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal–oxide–semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform. PMID:27882926

  8. A CMOS silicon spin qubit.

    PubMed

    Maurand, R; Jehl, X; Kotekar-Patil, D; Corna, A; Bohuslavskyi, H; Laviéville, R; Hutin, L; Barraud, S; Vinet, M; Sanquer, M; De Franceschi, S

    2016-11-24

    Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform.

  9. Density currents in the Chicago River: Characterization, effects on water quality, and potential sources

    USGS Publications Warehouse

    Jackson, P.R.; Garcia, C.M.; Oberg, K.A.; Johnson, K.K.; Garcia, M.H.

    2008-01-01

    Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants and affecting water quality. Detailed field observations of bidirectional flows were made in the Chicago River in Chicago, Illinois in the winter of 2005-06. Using multiple acoustic Doppler current profilers simultaneously with a water-quality profiler, the formation of upstream propagating density currents within the Chicago River both as an underflow and an overflow was observed on three occasions. Density differences driving the flow primarily arise from salinity differences between intersecting branches of the Chicago River, whereas water temperature is secondary in the creation of these currents. Deicing salts appear to be the primary source of salinity in the North Branch of the Chicago River, entering the waterway through direct runoff and effluent from a wastewater-treatment plant in a large metropolitan area primarily served by combined sewers. Water-quality assessments of the Chicago River may underestimate (or overestimate) the impairment of the river because standard water-quality monitoring practices do not account for density-driven underflows (or overflows). Chloride concentrations near the riverbed can significantly exceed concentrations at the river surface during underflows indicating that full-depth parameter profiles are necessary for accurate water-quality assessments in urban environments where application of deicing salt is common.

  10. On the problems of stability and durability of field-emission current sources for electrovacuum devices

    NASA Astrophysics Data System (ADS)

    Yakunin, Alexander N.; Aban'shin, Nikolay P.; Akchurin, Garif G.; Akchurin, Georgy G.; Avetisyan, Yuri A.

    2016-03-01

    The results of the practical implementation of the concept of field-emission current source with high average current density of 0.1-0.3 A-cm-2 are shown. The durability of cathode samples at a level of 6000 hours is achieved under conditions of technical vacuum. A phenomenological model is suggested that describes the tunneling of both equilibrium and nonequilibrium electrons in a vacuum from the zone of concentration of electrostatic field. Conditions are discussed as the resulting increase in the emission current due to the connection mechanism of the photoelectric effect is thermodynamically favorable, that is not accompanied by an undesirable increase in the temperature of the local emission zone. It is shown that to ensure stability and durability of the cathode is also important to limit the concentration of equilibrium carriers using composite structures «DLC film on Mo substrate." This helps to reduce the criticality of the CVC. A possible alternative is to use a restrictive resistance in the cathode. However, this increases the heat losses and thus decreases assembly efficiency. The results of experimental studies of the structure showing the saturation of photoemission current component with an increase in operating voltage. This fact suggests the existence of an effective mechanism for control of emission at constant operating voltage. This is fundamentally important for the stabilization of field emission cathode, providing a reliability and durability. The single-photon processes and the small thickness DLC films (15-20 nm) provide high-speed process of control.

  11. Density currents in the Chicago River: Characterization, effects on water quality, and potential sources

    USGS Publications Warehouse

    Jackson, P. Ryan; Garcia, Carlos M.; Oberg, Kevin A.; Johnson, Kevin K.; Garcia, Marcelo H.

    2008-01-01

    Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants and affecting water quality. Detailed field observations of bidirectional flows were made in the Chicago River in Chicago, Illinois in the winter of 2005-06. Using multiple acoustic Doppler current profilers simultaneously with a water-quality profiler, the formation of upstream propagating density currents within the Chicago River both as an underflow and an overflow was observed on three occasions. Density differences driving the flow primarily arise from salinity differences between intersecting branches of the Chicago River, whereas water temperature is secondary in the creation of these currents. Deicing salts appear to be the primary source of salinity in the North Branch of the Chicago River, entering the waterway through direct runoff and effluent from a wastewater-treatment plant in a large metropolitan area primarily served by combined sewers. Water-quality assessments of the Chicago River may underestimate (or overestimate) the impairment of the river because standard water-quality monitoring practices do not account for density-driven underflows (or overflows). Chloride concentrations near the riverbed can significantly exceed concentrations at the river surface during underflows indicating that full-depth parameter profiles are necessary for accurate water-quality assessments in urban environments where application of deicing salt is common.

  12. Density currents in the Chicago River: characterization, effects on water quality, and potential sources.

    PubMed

    Jackson, P Ryan; García, Carlos M; Oberg, Kevin A; Johnson, Kevin K; García, Marcelo H

    2008-08-15

    Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants and affecting water quality. Detailed field observations of bidirectional flows were made in the Chicago River in Chicago, Illinois in the winter of 2005-06. Using multiple acoustic Doppler current profilers simultaneously with a water-quality profiler, the formation of upstream propagating density currents within the Chicago River both as an underflow and an overflow was observed on three occasions. Density differences driving the flow primarily arise from salinity differences between intersecting branches of the Chicago River, whereas water temperature is secondary in the creation of these currents. Deicing salts appear to be the primary source of salinity in the North Branch of the Chicago River, entering the waterway through direct runoff and effluent from a wastewater-treatment plant in a large metropolitan area primarily served by combined sewers. Water-quality assessments of the Chicago River may underestimate (or overestimate) the impairment of the river because standard water-quality monitoring practices do not account for density-driven underflows (or overflows). Chloride concentrations near the riverbed can significantly exceed concentrations at the river surface during underflows indicating that full-depth parameter profiles are necessary for accurate water-quality assessments in urban environments where application of deicing salt is common.

  13. CCD/CMOS hybrid FPA for low light level imaging

    NASA Astrophysics Data System (ADS)

    Liu, Xinqiao; Fowler, Boyd A.; Onishi, Steve K.; Vu, Paul; Wen, David D.; Do, Hung; Horn, Stuart

    2005-08-01

    We present a CCD / CMOS hybrid focal plane array (FPA) for low light level imaging applications. The hybrid approach combines the best of CCD imaging characteristics (e.g. high quantum efficiency, low dark current, excellent uniformity, and low pixel cross talk) with the high speed, low power and ultra-low read noise of CMOS readout technology. The FPA is comprised of two CMOS readout integrated circuits (ROIC) that are bump bonded to a CCD imaging substrate. Each ROIC is an array of Capacitive Transimpedence Amplifiers (CTIA) that connect to the CCD columns via indium bumps. The proposed column parallel readout architecture eliminates the slow speed, high noise, and high power limitations of a conventional CCD. This results in a compact, low power, ultra-sensitive solid-state FPA that can be used in low light level applications such as live-cell microscopy and security cameras at room temperature operation. The prototype FPA has a 1280×1024 format with 12-um square pixels. Measured dark current is less than 5.8 pA/cm2 at room temperature and the overall read noise is as low as 2.9e at 30 frames/sec.

  14. Simple BiCMOS CCCTA design and resistorless analog function realization.

    PubMed

    Tangsrirat, Worapong

    2014-01-01

    The simple realization of the current-controlled conveyor transconductance amplifier (CCCTA) in BiCMOS technology is introduced. The proposed BiCMOS CCCTA realization is based on the use of differential pair and basic current mirror, which results in simple structure. Its characteristics, that is, parasitic resistance (R x) and current transfer (i o/i z), are also tunable electronically by external bias currents. The realized circuit is suitable for fabrication using standard 0.35 μm BiCMOS technology. Some simple and compact resistorless applications employing the proposed CCCTA as active elements are also suggested, which show that their circuit characteristics with electronic controllability are obtained. PSPICE simulation results demonstrating the circuit behaviors and confirming the theoretical analysis are performed.

  15. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Accelerated life tests were performed on CMOS microcircuits to predict their long term reliability. The consistency of the CMOS microcircuit activation energy between the range of 125 C to 200 C and the range 200 C to 250 C was determined. Results indicate CMOS complexity and the amount of moisture detected inside the devices after testing influences time to failure of tested CMOS devices.

  16. Spatial temperature control with a 27 MHz current source interstitial hyperthermia system.

    PubMed

    Kaatee, R S; Crezee, H; Kanis, B P; Lagendijk, J J; Levendag, P C; Visser, A G

    1997-01-01

    This article gives an overview of the properties of a 27 MHz current source interstitial hyperthermia system, affecting temperature uniformity. Applicators can be inserted in standard flexible afterloading catheters. Maximum temperatures are measured with seven-point constantan-manganin thermocouple probes inside each applicator. Temperature can be controlled automatically using a simple control algorithm. Three-dimensional power absorption and thermal models for inhomogeneous tissues are available to optimize applicator geometry and phase configuration. Properties of the interstitial heating system have been verified both in phantom experiments and in in vivo treatments of rhabdomyosarcomas implanted in the flank of a rat. An experiment with four electrodes in one catheter proves that longitudinal control of the specific absorption rate (SAR) is feasible. Local cooling applied by cold water circulation through a catheter perpendicular to the afterloading catheter could be compensated by independent control of electrode power. Furthermore, comparison of two different phase configurations using four dual electrode applicators shows that the SAR distribution can be manipulated significantly, utilizing the phase of the electrodes. Finally, the temperature can be controlled safely and model calculations are in fair agreement with the measurements. The features of the 27 MHz current source interstitial hyperthermia system enable spatial temperature control at approximately 1.5 cm.

  17. Suppression of the 1 MHz beam current modulation in the LEDA/CRITS proton source

    SciTech Connect

    Balleyguier, P.; Sherman, J.; Zaugg, T.

    1998-12-01

    Earlier operation of a microwave proton source exhibited an approximate 1-MHz modulation in the beam current. This oscillation could cause instabilities at higher energies in the linac, as the low-level RF control for linac operation rolls off at 200 kHz. Tests on a dummy load show the modulation is created by the magnetron itself: at a typical power level required for the source operation (680W), the 1-MHz sideband level was as high as {minus}4 dB from carrier. Since the magnetron exhibited better behavior at higher levels, a RF power attenuator is inserted to force the magnetron to run at a 50% higher power level for the same final power in the load. This attenuator is made of two antennas plunged in the waveguide and connected to dummy loads by a coaxial line. As the antenna are separated by a quarter of the guided wavelength, mismatching effects approximately cancel each other. The antenna length is experimentally adjusted to obtain the {minus}1.8 dB attenuation required. Magnetron operation at the higher power level gives a beam current spectrum free of the 1-MHz modulation, showing the coherent beam noise is not generated by plasma chamber phenomena.

  18. CMOS-APS Detectors for Solar Physics: Lessons Learned during the SWAP Preflight Calibration

    NASA Astrophysics Data System (ADS)

    de Groof, A.; Berghmans, D.; Nicula, B.; Halain, J.-P.; Defise, J.-M.; Thibert, T.; Schühle, U.

    2008-05-01

    CMOS-APS imaging detectors open new opportunities for remote sensing in solar physics beyond what classical CCDs can provide, offering far less power consumption, simpler electronics, better radiation hardness, and the possibility of avoiding a mechanical shutter. The SWAP telescope onboard the PROBA2 technology demonstration satellite of the European Space Agency will be the first actual implementation of a CMOS-APS detector for solar physics in orbit. One of the goals of the SWAP project is precisely to acquire experience with the CMOS-APS technology in a real-live space science context. Such a precursor mission is essential in the preparation of missions such as Solar Orbiter where the extra CMOS-APS functionalities will be hard requirements. The current paper concentrates on specific CMOS-APS issues that were identified during the SWAP preflight calibration measurements. We will discuss the different readout possibilities that the CMOS-APS detector of SWAP provides and their associated pros and cons. In particular we describe the “image lag” effect, which results in a contamination of each image with a remnant of the previous image. We have characterised this effect for the specific SWAP implementation and we conclude with a strategy on how to successfully circumvent the problem and actually take benefit of it for solar monitoring.

  19. Drift velocity of charged particles in magnetic fields and its relation to the direction of the source current

    NASA Astrophysics Data System (ADS)

    Essén, Hanno; Nordmark, Arne B.

    2016-10-01

    Integrable motion of charged particles in magnetic fields produced by stationary current distributions is investigated. We treat motion in the magnetic field from an infinite flat current sheet, a Harris current sheath, an infinite rectilinear current, and a dipole in its equatorial plane. We find that positively charged particles as a rule will drift in the same direction as the current that is the source of the magnetic field in question. The conclusion is that charged particles moving under the influence of current distributions tend to enhance the current and that this indicates current self-amplification.

  20. Municipal solid waste (MSW) as a renewable source of energy: current and future practices in China.

    PubMed

    Cheng, Hefa; Hu, Yuanan

    2010-06-01

    With rapid economic growth and massive urbanization, China faces the problem of municipal solid waste (MSW) disposal and the pressing need for development of alternative energy. Waste-to-energy (WTE) incineration, which recovers energy from discarded MSW and produces electricity and/or steam for heating, is recognized as a renewable source of energy and is playing an increasingly important role in MSW management in China. This article provides an overview of the WTE industry, discusses the major challenges in expanding WTE incineration in China, namely, high capital and operational costs, equipment corrosion, air pollutant emissions, and fly ash disposal. A perspective on MSW as a renewable energy source in China is also presented. Currently, only approximately 13% of MSW generated in China is disposed in WTE facilities. With the significant benefits of environmental quality, the reduction of greenhouse gas (GHG) emissions, and government policies and financial incentives as a renewable energy source, WTE incineration industry is expected to experience significant growth in the coming decade and make greater contribution to supplying renewable energy in China.

  1. Current status of cadaver sources in Turkey and a wake-up call for Turkish anatomists.

    PubMed

    Gürses, İlke Ali; Coşkun, Osman; Öztürk, Adnan

    2017-06-28

    Persisting difficulties in body procurement in Turkey led to the acquisition of donated, unclaimed, autopsied, and imported bodies regulated under current legislature. Yet, no study had investigated the extent of the on-going cadaver problem. This study was aimed to outline cadaver sources in anatomy departments and their effectiveness by means of an online survey. Additionally, official websites of each department were investigated regarding any information on body donation. Unclaimed cadavers (84.8%) were the major source for anatomy departments, followed by donated (50%) and imported cadavers (39.1%). Foundation-based medical faculties were more likely to import cadavers (P = 0.008). There was a moderate increase (rs  = 0.567; P = 0.018) in donation registrations to our department after 2000. The departments in cities with significantly higher City-Based Gross Domestic Product measures (US$9,900 vs. US$16,772, P = 0.041), frequencies for mid- or high-school graduates (30.4% vs. 31.3%, P = 0.041), and frequencies for under- or post-graduates (13.1% vs. 15.8%, P = 0.24) had managed to use donated cadavers. Anatomy departments' major reasons for using unclaimed cadavers were education (45.9%), unclaimed cadavers being the only source (24.3%), and receiving inadequate donations (21.6%). Nine out of seventy-four departments (12.2%) provided information regarding body donation on their websites. Body procurement remains as a serious problem in Turkey and it is apparent that current legislature does not provide a sufficient cadaver inflow. Similarly, anatomy departments' effectiveness in public awareness of body donation and support in the National Body Donation Campaign seems questionable. Anat Sci Educ, © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

  2. Current density distributions and sputter marks in electron cyclotron resonance ion sources

    SciTech Connect

    Panitzsch, Lauri; Peleikis, Thies; Boettcher, Stephan; Stalder, Michael; Wimmer-Schweingruber, Robert F.

    2013-01-15

    Most electron cyclotron resonance ion sources use hexapolar magnetic fields for the radial confinement of the plasma. The geometry of this magnetic structure is then-induced by charged particles-mapped onto the inner side of the plasma electrode via sputtering and deposition. The resulting structures usually show two different patterns: a sharp triangular one in the central region which in some cases is even sputtered deep into the material (referred to as thin groove or sharp structure), and a blurred but still triangular-like one in the surroundings (referred to as broad halo). Therefore, both patterns seem to have different sources. To investigate their origins we replaced the standard plasma electrode by a custom-built plasma electrode acting as a planar, multi-segment current-detector. For different biased disc voltages, detector positions, and source biases (referred to the detector) we measured the electrical current density distributions in the plane of the plasma electrode. The results show a strong and sharply confined electron population with triangular shape surrounded by less intense and spatially less confined ions. Observed sputter- and deposition marks are related to the analysis of the results. Our measurements suggest that the two different patterns (thin and broad) indeed originate from different particle populations. The thin structures seem to be caused by the hot electron population while the broad marks seem to stem from the medium to highly charged ions. In this paper we present our measurements together with theoretical considerations and substantiate the conclusions drawn above. The validity of these results is also discussed.

  3. Current density distributions and sputter marks in electron cyclotron resonance ion sources.

    PubMed

    Panitzsch, Lauri; Peleikis, Thies; Böttcher, Stephan; Stalder, Michael; Wimmer-Schweingruber, Robert F

    2013-01-01

    Most electron cyclotron resonance ion sources use hexapolar magnetic fields for the radial confinement of the plasma. The geometry of this magnetic structure is then--induced by charged particles--mapped onto the inner side of the plasma electrode via sputtering and deposition. The resulting structures usually show two different patterns: a sharp triangular one in the central region which in some cases is even sputtered deep into the material (referred to as thin groove or sharp structure), and a blurred but still triangular-like one in the surroundings (referred to as broad halo). Therefore, both patterns seem to have different sources. To investigate their origins we replaced the standard plasma electrode by a custom-built plasma electrode acting as a planar, multi-segment current-detector. For different biased disc voltages, detector positions, and source biases (referred to the detector) we measured the electrical current density distributions in the plane of the plasma electrode. The results show a strong and sharply confined electron population with triangular shape surrounded by less intense and spatially less confined ions. Observed sputter- and deposition marks are related to the analysis of the results. Our measurements suggest that the two different patterns (thin and broad) indeed originate from different particle populations. The thin structures seem to be caused by the hot electron population while the broad marks seem to stem from the medium to highly charged ions. In this paper we present our measurements together with theoretical considerations and substantiate the conclusions drawn above. The validity of these results is also discussed.

  4. Distributed point source method for the modeling of a three-dimensional eddy current NDE problem

    NASA Astrophysics Data System (ADS)

    Bore, T.; Joubert, P.-Y.; Placko, D.

    2014-03-01

    This paper deals with modeling in electromagnetism in the field of eddy current for Non Destructive Evaluation. Several techniques could be used to diagnose structural damages. In eddy current application, a magnetic field generates by an excitation coil (or primary coil), interacts with a conductive target and generates eddy current. Variations in the phase and the magnitude of these eddy currents can be monitored using a second "receiver" coil. Variations in the physical properties (electrical conductivity, magnetic permeability,..) or the presence of any flaw in the target will cause a change in eddy current and a corresponding change in the phase and amplitude of measured signal. The interpretation of the signals requires a good understanding of the interaction between eddy current and structure. Therefore, researchers need analytical or numerical techniques to obtain a clear understanding of wave propagation behaviors. However, modeling of wave scattering phenomenon by conventional numerical techniques such as finite elements requires very fine mesh and heavy computational power. To go further, an innovative implementation of a semi-analytical modeling method, called the Distributed Points Source Method (DPSM), has been developed and used. The DPSM has already shown great potentialities for the versatile and computationally efficient modeling of complex electrostatic, electromagnetic or ultrasounic problems. In this paper, we report on a new implementation of the DPSM, called differential DPSM, which shows interesting prospects for the modeling of complex eddy current problems. In parallel, an Eddy Current Imager (ECI) has been recently developed in our laboratory in the aim of imaging cracks in metallic structures. In this paper, a simplified modeling of the ECI is presented using DPSM technique, the basics of DPSM formalism being firstly developed. A comparison between experimental and computed data obtained for a millimetric surface defect is presented in

  5. Current use of imaging and electromagnetic source localization procedures in epilepsy surgery centers across Europe.

    PubMed

    Mouthaan, Brian E; Rados, Matea; Barsi, Péter; Boon, Paul; Carmichael, David W; Carrette, Evelien; Craiu, Dana; Cross, J Helen; Diehl, Beate; Dimova, Petia; Fabo, Daniel; Francione, Stefano; Gaskin, Vladislav; Gil-Nagel, Antonio; Grigoreva, Elena; Guekht, Alla; Hirsch, Edouard; Hecimovic, Hrvoje; Helmstaedter, Christoph; Jung, Julien; Kalviainen, Reetta; Kelemen, Anna; Kimiskidis, Vasilios; Kobulashvili, Teia; Krsek, Pavel; Kuchukhidze, Giorgi; Larsson, Pål G; Leitinger, Markus; Lossius, Morten I; Luzin, Roman; Malmgren, Kristina; Mameniskiene, Ruta; Marusic, Petr; Metin, Baris; Özkara, Cigdem; Pecina, Hrvoje; Quesada, Carlos M; Rugg-Gunn, Fergus; Rydenhag, Bertil; Ryvlin, Philippe; Scholly, Julia; Seeck, Margitta; Staack, Anke M; Steinhoff, Bernhard J; Stepanov, Valentin; Tarta-Arsene, Oana; Trinka, Eugen; Uzan, Mustafa; Vogt, Viola L; Vos, Sjoerd B; Vulliémoz, Serge; Huiskamp, Geertjan; Leijten, Frans S S; Van Eijsden, Pieter; Braun, Kees P J

    2016-05-01

    In 2014 the European Union-funded E-PILEPSY project was launched to improve awareness of, and accessibility to, epilepsy surgery across Europe. We aimed to investigate the current use of neuroimaging, electromagnetic source localization, and imaging postprocessing procedures in participating centers. A survey on the clinical use of imaging, electromagnetic source localization, and postprocessing methods in epilepsy surgery candidates was distributed among the 25 centers of the consortium. A descriptive analysis was performed, and results were compared to existing guidelines and recommendations. Response rate was 96%. Standard epilepsy magnetic resonance imaging (MRI) protocols are acquired at 3 Tesla by 15 centers and at 1.5 Tesla by 9 centers. Three centers perform 3T MRI only if indicated. Twenty-six different MRI sequences were reported. Six centers follow all guideline-recommended MRI sequences with the proposed slice orientation and slice thickness or voxel size. Additional sequences are used by 22 centers. MRI postprocessing methods are used in 16 centers. Interictal positron emission tomography (PET) is available in 22 centers; all using 18F-fluorodeoxyglucose (FDG). Seventeen centers perform PET postprocessing. Single-photon emission computed tomography (SPECT) is used by 19 centers, of which 15 perform postprocessing. Four centers perform neither PET nor SPECT in children. Seven centers apply magnetoencephalography (MEG) source localization, and nine apply electroencephalography (EEG) source localization. Fourteen combinations of inverse methods and volume conduction models are used. We report a large variation in the presurgical diagnostic workup among epilepsy surgery centers across Europe. This diversity underscores the need for high-quality systematic reviews, evidence-based recommendations, and harmonization of available diagnostic presurgical methods. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  6. Field Emission Properties of Carbon Nanotube Fibers and Sheets for a High Current Electron Source

    NASA Astrophysics Data System (ADS)

    Christy, Larry

    Field emission (FE) properties of carbon nanotube (CNT) fibers from Rice University and the University of Cambridge have been studied for use within a high current electron source for a directed energy weapon. Upon reviewing the performance of these two prevalent CNT fibers, cathodes were designed with CNT fibers from the University of Cincinnati Nanoworld Laboratory. Cathodes composed of a single CNT fiber, an array of three CNT fibers, and a nonwoven CNT sheet were investigated for FE properties; the goal was to design a cathode with emission current in excess of 10 mA. Once the design phase was complete, the cathode samples were fabricated, characterized, and then analyzed to determine FE properties. Electrical conductivity of the CNT fibers was characterized with a 4-probe technique. FE characteristics were measured in an ultra-high vacuum chamber at Wright-Patterson Air Force Base. The arrayed CNT fiber and the enhanced nonwoven CNT sheet emitter design demonstrated the most promising FE properties. Future work will include further analysis and cathode design using this nonwoven CNT sheet material to increase peak current performance during electron emission.

  7. High yield neutron generator based on a high-current gasdynamic electron cyclotron resonance ion source

    SciTech Connect

    Skalyga, V.; Sidorov, A.; Izotov, I.; Golubev, S.; Razin, S.; Strelkov, A.; Tarvainen, O.; Koivisto, H.; Kalvas, T.

    2015-09-07

    In present paper, an approach for high yield compact D-D neutron generator based on a high current gasdynamic electron cyclotron resonance ion source is suggested. Results on dense pulsed deuteron beam production with current up to 500 mA and current density up to 750 mA/cm{sup 2} are demonstrated. Neutron yield from D{sub 2}O and TiD{sub 2} targets was measured in case of its bombardment by pulsed 300 mA D{sup +} beam with 45 keV energy. Neutron yield density at target surface of 10{sup 9} s{sup −1} cm{sup −2} was detected with a system of two {sup 3}He proportional counters. Estimations based on obtained experimental results show that neutron yield from a high quality TiD{sub 2} target bombarded by D{sup +} beam demonstrated in present work accelerated to 100 keV could reach 6 × 10{sup 10} s{sup −1} cm{sup −2}. It is discussed that compact neutron generator with such characteristics could be perspective for a number of applications like boron neutron capture therapy, security systems based on neutron scanning, and neutronography.

  8. A flexible curvilinear electromagnetic filter for direct current cathodic arc source

    SciTech Connect

    Dai Hua; Shen Yao; Li Liuhe; Li Xiaoling; Cai Xun; Chu, Paul K.

    2007-09-15

    Widespread applications of direct current (dc) cathodic arc deposition are hampered by macroparticle (MP) contamination, although a cathodic arc offers many unique merits such as high ionization rate, high deposition rate, etc. In this work, a flexible curvilinear electromagnetic filter is described to eliminate MPs from a dc cathodic arc source. The filter which has a relatively large size with a minor radius of about 85 mm is suitable for large cathodes. The filter is open and so the MPs do not rebound inside the filter. The flexible design allows the ions to be transported from the cathode to the sample surface optimally. Our measurements with a saturated ion current probe show that the efficiency of this flexible filter reaches about 2.0% (aluminum cathode) when the filter current is about 250 A. The MP density measured from TiN films deposited using this filter is two to three orders of magnitude less than that from films deposited with a 90 deg. duct magnetic filter and three to four orders of magnitude smaller than those deposited without a filter. Furthermore, our experiments reveal that the potential of the filter coil and the magnetic field on the surface of the cathode are two important factors affecting the efficacy of the filter. Different biasing potentials can enhance the efficiency to up to 12-fold, and a magnetic field at about 4.0 mT can improve it by a factor of 2 compared to 5.4 mT.

  9. Carbon nanotube integration with a CMOS process.

    PubMed

    Perez, Maximiliano S; Lerner, Betiana; Resasco, Daniel E; Pareja Obregon, Pablo D; Julian, Pedro M; Mandolesi, Pablo S; Buffa, Fabian A; Boselli, Alfredo; Lamagna, Alberto

    2010-01-01

    This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture.

  10. Spectrometry with consumer-quality CMOS cameras.

    PubMed

    Scheeline, Alexander

    2015-01-01

    Many modern spectrometric instruments use diode arrays, charge-coupled arrays, or CMOS cameras for detection and measurement. As portable or point-of-use instruments are desirable, one would expect that instruments using the cameras in cellular telephones and tablet computers would be the basis of numerous instruments. However, no mass market for such devices has yet developed. The difficulties in using megapixel CMOS cameras for scientific measurements are discussed, and promising avenues for instrument development reviewed. Inexpensive alternatives to use of the built-in camera are also mentioned, as the long-term question is whether it is better to overcome the constraints of CMOS cameras or to bypass them.

  11. Carbon Nanotube Integration with a CMOS Process

    PubMed Central

    Perez, Maximiliano S.; Lerner, Betiana; Resasco, Daniel E.; Pareja Obregon, Pablo D.; Julian, Pedro M.; Mandolesi, Pablo S.; Buffa, Fabian A.; Boselli, Alfredo; Lamagna, Alberto

    2010-01-01

    This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture. PMID:22319330

  12. A high fill-factor low dark leakage CMOS image sensor with shared-pixel design

    NASA Astrophysics Data System (ADS)

    Seo, Min-Woong; Yasutomi, Keita; Kagawa, Keiichiro; Kawahito, Shoji

    2014-03-01

    We have developed and evaluated the high responsivity and low dark leakage CMOS image sensor with the ring-gate shared-pixel design. A ring-gate shared-pixel design with a high fill factor makes it possible to achieve the low-light imaging. As eliminating the shallow trench isolation in the proposed pixel, the dark leakage current is significantly decreased because one of major dark leakage sources is removed. By sharing the in-pixel transistors such as a reset transistor, a select transistor, and a source follower amplifier, each pixel has a high fill-factor of 43 % and high sensitivity of 144.6 ke-/lx·sec. In addition, the effective number of transistors per pixel is 1.75. The proposed imager achieved the relatively low dark leakage current of about 104.5 e-/s (median at 60°C), corresponding to a dark current density Jdark_proposed of about 30 pA/cm2. In contrast, the conventional type test pixel has a large dark leakage current of 2450 e-/s (median at 60°C), corresponding to Jdark_conventional of about 700 pA/cm2. Both pixels have a same pixel size of 7.5×7.5 μm2 and are fabricated in same process.

  13. Laminar Distribution of Phase-Amplitude Coupling of Spontaneous Current Sources and Sinks

    PubMed Central

    Sotero, Roberto C.; Bortel, Aleksandra; Naaman, Shmuel; Mocanu, Victor M.; Kropf, Pascal; Villeneuve, Martin Y.; Shmuel, Amir

    2015-01-01

    Although resting-state functional connectivity is a commonly used neuroimaging paradigm, the underlying mechanisms remain unknown. Thalamo-cortical and cortico-cortical circuits generate oscillations at different frequencies during spontaneous activity. However, it remains unclear how the various rhythms interact and whether their interactions are lamina-specific. Here we investigated intra- and inter-laminar spontaneous phase-amplitude coupling (PAC). We recorded local-field potentials using laminar probes inserted in the forelimb representation of rat area S1. We then computed time-series of frequency-band- and lamina-specific current source density (CSD), and PACs of CSD for all possible pairs of the classical frequency bands in the range of 1–150 Hz. We observed both intra- and inter-laminar spontaneous PAC. Of 18 possible combinations, 12 showed PAC, with the highest measures of interaction obtained for the pairs of the theta/gamma and delta/gamma bands. Intra- and inter-laminar PACs involving layers 2/3–5a were higher than those involving layer 6. Current sinks (sources) in the delta band were associated with increased (decreased) amplitudes of high-frequency signals in the beta to fast gamma bands throughout layers 2/3–6. Spontaneous sinks (sources) of the theta and alpha bands in layers 2/3–4 were on average linked to dipoles completed by sources (sinks) in layer 6, associated with high (low) amplitudes of the beta to fast-gamma bands in the entire cortical column. Our findings show that during spontaneous activity, delta, theta, and alpha oscillations are associated with periodic excitability, which for the theta and alpha bands is lamina-dependent. They further emphasize the differences between the function of layer 6 and that of the superficial layers, and the role of layer 6 in controlling activity in those layers. Our study links theories on the involvement of PAC in resting-state functional connectivity with previous work that revealed lamina

  14. Comprehensive understanding of dark count mechanisms of single-photon avalanche diodes fabricated in deep sub-micron CMOS technologies

    NASA Astrophysics Data System (ADS)

    Xu, Yux; Xiang, Ping; Xie, Xiaopeng

    2017-03-01

    The dark count noise mechanisms of single-photon avalanche diodes (SPADs) fabricated in deep sub-micron (DSM) CMOS technologies are investigated in depth. An electric field dependence of tunneling model combined with carrier thermal generation is established for dark count rate (DCR) prediction. Applying the crucial parameters provided by Geiger mode TCAD simulation such as avalanche triggering probability and electric field distribution in the SPAD avalanche region, the individual contribution of each noise source to DCR is calculated for several SPADs in DSM CMOS technologies. The model calculation results reveal that the trap-assisted tunneling is the main DCR generation source for these DSM CMOS SPADs. With the increase of doping levels in the device avalanche region, the band-to-band tunneling will be the dominant factor that could lead to the higher DCR in scaled DSM CMOS technologies.

  15. A Glucose Biosensor Using CMOS Potentiostat and Vertically Aligned Carbon Nanofibers.

    PubMed

    Al Mamun, Khandaker A; Islam, Syed K; Hensley, Dale K; McFarlane, Nicole

    2016-08-01

    This paper reports a linear, low power, and compact CMOS based potentiostat for vertically aligned carbon nanofibers (VACNF) based amperometric glucose sensors. The CMOS based potentiostat consists of a single-ended potential control unit, a low noise common gate difference-differential pair transimpedance amplifier and a low power VCO. The potentiostat current measuring unit can detect electrochemical current ranging from 500 nA to 7 [Formula: see text] from the VACNF working electrodes with high degree of linearity. This current corresponds to a range of glucose, which depends on the fiber forest density. The potentiostat consumes 71.7 [Formula: see text] of power from a 1.8 V supply and occupies 0.017 [Formula: see text] of chip area realized in a 0.18 [Formula: see text] standard CMOS process.

  16. Status Epilepticus Induced Spontaneous Dentate Gyrus Spikes: In Vivo Current Source Density Analysis

    PubMed Central

    Flynn, Sean P.; Barrier, Sylvain; Scott, Rod C.; Lenck- Santini, Pierre-Pascal; Holmes, Gregory L.

    2015-01-01

    The dentate gyrus is considered to function as an inhibitory gate limiting excitatory input to the hippocampus. Following status epilepticus (SE), this gating function is reduced and granule cells become hyper-excitable. Dentate spikes (DS) are large amplitude potentials observed in the dentate gyrus (DG) of normal animals. DS are associated with membrane depolarization of granule cells, increased activity of hilar interneurons and suppression of CA3 and CA1 pyramidal cell firing. Therefore, DS could act as an anti-excitatory mechanism. Because of the altered gating function of the dentate gyrus following SE, we sought to investigate how DS are affected following pilocarpine-induced SE. Two weeks following lithium-pilocarpine SE induction, hippocampal EEG was recorded in male Sprague-Dawley rats with 16-channel silicon probes under urethane anesthesia. Probes were placed dorso-ventrally to encompass either CA1-CA3 or CA1-DG layers. Large amplitude spikes were detected from EEG recordings and subject to current source density analysis. Probe placement was verified histologically to evaluate the anatomical localization of current sinks and the origin of DS. In 9 of 11 pilocarpine-treated animals and two controls, DS were confirmed with large current sinks in the molecular layer of the dentate gyrus. DS frequency was significantly increased in pilocarpine-treated animals compared to controls. Additionally, in pilocarpine-treated animals, DS displayed current sinks in the outer, middle and/or inner molecular layers. However, there was no difference in the frequency of events when comparing between layers. This suggests that following SE, DS can be generated by input from medial and lateral entorhinal cortex, or within the dentate gyrus. DS were associated with an increase in multiunit activity in the granule cell layer, but no change in CA1. These results suggest that following SE there is an increase in DS activity, potentially arising from hyperexcitability along the

  17. Polycrystalline Mercuric Iodide Films on CMOS Readout Arrays

    PubMed Central

    Hartsough, Neal E.; Iwanczyk, Jan S.; Nygard, Einar; Malakhov, Nail; Barber, William C.; Gandhi, Thulasidharan

    2009-01-01

    We have created high-resolution x-ray imaging devices using polycrystalline mercuric iodide (HgI2) films grown directly onto CMOS readout chips using a thermal vapor transport process. Images from prototype 400×400 pixel HgI2-coated CMOS readout chips are presented, where the pixel grid is 30 μm × 30 μm. The devices exhibited sensitivity of 6.2 μC/Rcm2 with corresponding dark current of ∼2.7 nA/cm2, and a 80 μm FWHM planar image response to a 50 μm slit aperture. X-ray CT images demonstrate a point spread function sufficient to obtain a 50 μm spatial resolution in reconstructed CT images at a substantially reduced dose compared to phosphor-coated readouts. The use of CMOS technology allows for small pixels (30 μm), fast readout speeds (8 fps for a 3200×3200 pixel array), and future design flexibility due to the use of well-developed fabrication processes. PMID:20161098

  18. Low voltage electron multiplying CCD in a CMOS process

    NASA Astrophysics Data System (ADS)

    Dunford, Alice; Stefanov, Konstantin; Holland, Andrew

    2016-07-01

    Low light level and high-speed image sensors as required for space applications can suffer from a decrease in the signal to noise ratio (SNR) due to the photon-starved environment and limitations of the sensor's readout noise. The SNR can be increased by the implementation of Time Delay Integration (TDI) as it allows photoelectrons from multiple exposures to be summed in the charge domain with no added noise. Electron Multiplication (EM) can further improve the SNR and lead to an increase in device performance. However, both techniques have traditionally been confined to Charge Coupled Devices (CCD) due to the efficient charge transfer required. With the increase in demand for CMOS sensors with equivalent or superior functionality and performance, this paper presents findings from the characterisation of a low voltage EMCCD in a CMOS process using advanced design features to increase the electron multiplying gain. By using the CMOS process, it is possible to increase chip integration and functionality and achieve higher readout speeds and reduced pixel size. The presented characterisation results include analysis of the photon transfer curve, the dark current, the electron multiplying gain and analysis of the parameters' dependence on temperature and operating voltage.

  19. Unity PF current-source rectifier based on dynamic trilogic PWM

    SciTech Connect

    Xiao Wang; Boon-Teck Ooi . Dept. of Electrical Engineering)

    1993-07-01

    One remaining step in perfecting the stand-along, unity power factor, regulated current-source PWM rectifier is to reduce cost, by bringing the 12-valve converter (consisting of three single-phase full bridges that operate with two-level or bilogic PWM) to the six-valve bridge. However, the six-valve topology requires a three-level or trilogic PWM strategy that can handle feedback signals. This feature was not available until now. The paper describes a general method of translating three-phase bilogic PWM signals to three-phase trilogic PWM signals. The method of translation retains the characteristics of the bilogic PWM, including the frequency bandwidth. Experiments show that the trilogic PWM signals produced by the method can not only handle stabilizing feedback signals but also signals for active filtering.

  20. Current source density estimation and interpolation based on the spherical harmonic Fourier expansion.

    PubMed

    Pascual-Marqui, R D; Gonzalez-Andino, S L; Valdes-Sosa, P A; Biscay-Lirio, R

    1988-12-01

    A method for the spatial analysis of EEG and EP data, based on the spherical harmonic Fourier expansion (SHE) of scalp potential measurements, is described. This model provides efficient and accurate formulas for: (1) the computation of the surface Laplacian and (2) the interpolation of electrical potentials, current source densities, test statistics and other derived variables. Physiologically based simulation experiments show that the SHE method gives better estimates of the surface Laplacian than the commonly used finite difference method. Cross-validation studies for the objective comparison of different interpolation methods demonstrate the superiority of the SHE over the commonly used methods based on the weighted (inverse distance) average of the nearest three and four neighbor values.

  1. Current-source density analysis of slow brain potentials during time estimation.

    PubMed

    Gibbons, Henning; Rammsayer, Thomas H

    2004-11-01

    Two event-related potential studies were conducted to investigate differential brain correlates of temporal processing of intervals below and above 3-4 s. In the first experiment, 24 participants were presented with auditorily marked target durations of 2, 4, and 6 s that had to be reproduced. Timing accuracy was similar for all three target durations. As revealed by current-source density analysis, slow-wave components during both presentation and reproduction were independent of target duration. Experiment 2 examined potential modulating effects of type of interval (filled and empty) and presentation mode (randomized and blocked presentation of target durations). Behavioral and slow-wave findings were consistent with those of Experiment 1. Thus, the present findings support the notion of a general timing mechanism irrespective of interval duration as proposed by scalar timing theory and pacemaker-counter models of time estimation.

  2. Stem cell sources for tooth regeneration: current status and future prospects.

    PubMed

    Otsu, Keishi; Kumakami-Sakano, Mika; Fujiwara, Naoki; Kikuchi, Kazuko; Keller, Laetitia; Lesot, Hervé; Harada, Hidemitsu

    2014-01-01

    Stem cells are capable of renewing themselves through cell division and have the remarkable ability to differentiate into many different types of cells. They therefore have the potential to become a central tool in regenerative medicine. During the last decade, advances in tissue engineering and stem cell-based tooth regeneration have provided realistic and attractive means of replacing lost or damaged teeth. Investigation of embryonic and adult (tissue) stem cells as potential cell sources for tooth regeneration has led to many promising results. However, technical and ethical issues have hindered the availability of these cells for clinical application. The recent discovery of induced pluripotent stem (iPS) cells has provided the possibility to revolutionize the field of regenerative medicine (dentistry) by offering the option of autologous transplantation. In this article, we review the current progress in the field of stem cell-based tooth regeneration and discuss the possibility of using iPS cells for this purpose.

  3. A high-current microwave ion source with permanent magnet and its beam emittance measurement

    SciTech Connect

    Yao Zeen; Tan Xinjian; Du Hongxin; Luo Ben; Liu Zhanwen

    2008-07-15

    The progress of a 2.45 GHz high-current microwave ion source with permanent magnet for T(d,n){sup 4}He reaction neutron generator is reported in this paper. At 600 W microwave power and 22 kV extraction voltage, 90 mA peak hydrogen ion beam is extracted from a single aperture of 6 mm diameter. The beam emittance is measured using a simplified pepper-pot method. The (x,x{sup '}) emittance and the (y,y{sup '}) emittance for 14 keV hydrogen ion beam are 55.3{pi} and 58.2{pi} mm mrad, respectively. The normalized emittances are 0.302{pi} and 0.317{pi} mm mrad, respectively.

  4. Analysis and application of two-current-source circuit as a signal conditioner for resistive sensors

    NASA Astrophysics Data System (ADS)

    Idzkowski, Adam; Gołębiowski, Jerzy; Walendziuk, Wojciech

    2017-05-01

    The article presents the analysis of metrological properties of a two-current-source supplied circuit. It includes such data as precise and simplified equations for two circuit output voltages in the function of relative resistance increments of sensors. Moreover, graphs showing nonlinearity coefficients of both output voltages for two resistance increments varying widely are presented. Graphs of transfer resistances, depending on relative increments of sensors resistance were also created. The article also contains a description of bridge-based circuit realization with the use of a computer and a data acquisition (DAQ) card. Laboratory measurement of the difference and sum of relative resistance increments of two resistance decade boxes were carried out indirectly with the use of the created measurement system. Measurement errors were calculated and included in the article, as well.

  5. Towards an ankle neuroprosthesis for hybrid robotics: Concepts and current sources for functional electrical stimulation.

    PubMed

    Casco, S; Fuster, I; Galeano, R; Moreno, J C; Pons, J L; Brunetti, F

    2017-07-01

    Hybrid rehabilitation robotics combine neuro-prosthetic devices (close-loop functional electrical stimulation systems) and traditional robotic structures and actuators to explore better therapies and promote a more efficient motor function recovery or compensation. Although hybrid robotics and ankle neuroprostheses (NPs) have been widely developed over the last years, there are just few studies on the use of NPs to electrically control both ankle flexion and extension to promote ankle recovery and improved gait patterns in paretic limbs. The aim of this work is to develop an ankle NP specifically designed to work in the field of hybrid robotics. This article presents early steps towards this goal and makes a brief review about motor NPs and Functional Electrical Stimulation (FES) principles and most common devices used to aid the ankle functioning during the gait cycle. It also shows a current sources analysis done in this framework, in order to choose the best one for this intended application.

  6. Compact non-local modeling of impact ionization in SOI MOSFETs for optimal CMOS device/circuit design

    NASA Astrophysics Data System (ADS)

    Krishnan, S.; Fossum, J. G.

    1996-05-01

    A comprehensive but compact non-local model for impact ionization current in scaled SOI MOSFETs is developed. The model, applicable to both fully depleted and non-fully depleted SOI CMOS, is intended for device/circuit simulation and has been implemented as post-processing in a circuit simulator SOISPICE [J. G. Fossum, SOI-SPICE-4 ( FD/SOI and NFD/SOI MOSFET Models). University of Florida, Gainesville, FL (March 1995)]. The model is based on transforming the empirical field-dependent impact ionization rate into a carrier temperature-dependent one via a quasi-steady-state approximation of the energy balance equation. The model is valid for weak as well as strong inversion. It is verified via predictions of structure-dependent drain-source breakdown and current kinks in a variety of floating-body SOI MOSFETs. SOISPICE simulations reveal insight into the design optimization of scaled SOI CMOS devices and circuits in which the breakdown, due to the parasitic BJT driven by impact ionization, must be controlled.

  7. Novel high peak current pulsed diode laser sources for direct material processing

    NASA Astrophysics Data System (ADS)

    Traub, M.; Bock, M.; Hoffmann, H.-D.; Bartram, M.

    2007-02-01

    Diode laser systems are well established for applications which demand high continuous wave (cw) power. These applications are material processing like cutting and welding of metals as well as polymers where diode laser systems are less expensive and more compact than solid state lasers. Even though the optical output power and the beam quality of diode lasers are increasing steadily, the use of these sources is generally limited to cw applications. For processes during which ablating of material is demanded, however, conventional diode lasers are inferior compared to pulsed solid state lasers as diode lasers suffer from the absence of optical intracavity q-switching. Some examples of these applications are coating removal and marking. To overcome this drawback, we have developed several diode laser systems that use high peak-current drivers and thereby allow to operate the diode lasers at currents up to 500 A. The pulse source was tested with fiber coupled single emitters, conventional diode lasers and customized AR-coated diode laser bars. With the new diode laser driver, a peak output power of 250 W can be achieved with pulse durations of approx. 100 ns. Polarization coupling of two bars increases the power by a factor of two. Thereby an output power of 500 W can be demonstrated. These systems reach an intensity of 27 MW/cm2 per diode laser bar which is sufficient for ablating processes. We will demonstrate the design of the prototype system as well as results of marking and coating removal experiments with the system.

  8. The current status of the development of renewable energy sources worldwide and in Russia

    NASA Astrophysics Data System (ADS)

    Fortov, V. E.; Popel', O. S.

    2014-06-01

    Resorting to renewable energy sources (RESs) as one of the bases of the promising world energy industry has become a logical result of the historical development and the recognition that is necessary to diversify primary energy sources being used, with the aim of enhancing both energy and ecological security of countries, regions, and concrete energy consumers. The review of the development of new technologies used for conversion of RESs, the progress of which can be characterized by the fact that by the year 2013 the total generating capacity of RES-based power plants now in operation has amounted to 500 GW—by a factor of 1.5 more than the total generating capacity of all nuclear power stations in the world. The paper presents an analysis of the current status of RESs and problems that restrain their development in Russia. It is noted that the peculiarities of the energy situation in Russia impose the specific requirements upon drawing up the programs of the development of RESs. Along with the use of RESs as part of systems of centralized energy supply, which is a priority for most industrially developed countries and promises the most large-scale introduction of RESs in Russia, it is necessary, first of all, to give attention to the development and creation of systems for independent supply of consumers with power and heat and the development of distributed powergenerating systems using RESs.

  9. High-current diode with ferroelectric plasma source-assisted hollow anode

    SciTech Connect

    Vekselman, V.; Gleizer, J. Z.; Yatom, S.; Gurovich, V. Tz.; Krasik, Ya. E.

    2010-11-15

    The operation of a ferroelectric plasma source-assisted hollow anode (HA) electron source in a vacuum diode powered by an {approx}200 kV and {approx}400 ns pulsed generator was studied using time- and space-resolved laser induced fluorescence diagnostics. It was found that the plasma ion ''temperature'' in the vicinity of the HA output grid increases up to {approx}15 eV during the accelerating pulse, which is consistent with a model of the potential screening of the grid by the randomly moving ions [Phys. Plasmas 13, 073506 (2006)]. Also it was shown that the increase in the HA plasma potential up to several kilovolts because of the appearance of a noncompensated ion charge in the HA bulk plasma due to electrons fast extraction, leads to explosive emission centers being generated at the HA grid and to nonuniformity in the cross-sectional electron beam current density. Finally, the plasma prefilled mode of diode operation was studied using a simple one-dimensional model of the plasma erosion and the HA plasma electron heating by energetic ions was considered.

  10. The adequacy of current import and export controls on sealed radioactive sources.

    SciTech Connect

    Longley, Susan W.; Cochran, John Russell; Price, Laura L.; Lipinski, Kendra J.

    2003-10-01

    Millions of sealed radioactive sources (SRSs) are being used for a wide variety of beneficial purposes throughout the world. Security experts are now concerned that these beneficial SRSs could be used in a radiological dispersion device to terrorize and disrupt society. The greatest safety and security threat is from those highly radioactive Category 1 and 2 SRSs. Without adequate controls, it may be relatively easy to legally purchase a Category 1 or 2 SRS on the international market under false pretenses. Additionally, during transfer, SRSs are particularly susceptible to theft since the sources are in a shielded and mobile configuration, transportation routes are predictable, and shipments may not be adequately guarded. To determine if government controls on SRS are adequate, this study was commissioned to review the current SRS import and export controls of six countries. Canada, the Russian Federation, and South Africa were selected as the exporting countries, and Egypt, the Philippines, and the United States were selected as importing countries. A detailed review of the controls in each country is presented. The authors found that Canada and Russia are major exporters, and are exporting highly radioactive SRSs without first determining if the recipient is authorized by the receiving country to own and use the SRSs. Available evidence was used to estimate that on average there are tens to possibly hundreds of intercountry transfers of highly radioactive SRSs each day. Based on these and other findings, this reports recommends stronger controls on the export and import of highly radioactive SRSs.

  11. Silicon-gate CMOS/SOS processing

    NASA Technical Reports Server (NTRS)

    Ramondetta, P.

    1979-01-01

    Major silicon-gate CMOS/SOS processes are described. Sapphire substrate preparation is also discussed, as well as the following process variations: (1) the double epi process; and (2) ion implantation.

  12. CMOS analog switches for adaptive filters

    NASA Technical Reports Server (NTRS)

    Dixon, C. E.

    1980-01-01

    Adaptive active low-pass filters incorporate CMOS (Complimentary Metal-Oxide Semiconductor) analog switches (such as 4066 switch) that reduce variation in switch resistance when filter is switched to any selected transfer function.

  13. A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems.

    PubMed

    Yan Lu; Wing-Hung Ki

    2014-06-01

    A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude |VAC|. The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 μm CMOS N-well process with active area of 0.0651 mm(2). For the proposed rectifier measured at |VAC| = 3.0 V, the voltage conversion ratios are 0.89 and 0.93 for RL=500 Ω and 5 kΩ, respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with |VAC| ranges from 1.5 to 4 V for RL=500 Ω.

  14. Measuring bi-directional current through a field-effect transistor by virtue of drain-to-source voltage measurement

    DOEpatents

    Turner, Steven Richard

    2006-12-26

    A method and apparatus for measuring current, and particularly bi-directional current, in a field-effect transistor (FET) using drain-to-source voltage measurements. The drain-to-source voltage of the FET is measured and amplified. This signal is then compensated for variations in the temperature of the FET, which affects the impedance of the FET when it is switched on. The output is a signal representative of the direction of the flow of current through the field-effect transistor and the level of the current through the field-effect transistor. Preferably, the measurement only occurs when the FET is switched on.

  15. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    PubMed

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  16. First test of BNL electron beam ion source with high current density electron beam

    NASA Astrophysics Data System (ADS)

    Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard

    2015-01-01

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm2 and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  17. First test of BNL electron beam ion source with high current density electron beam

    SciTech Connect

    Pikin, Alexander Alessi, James G. Beebe, Edward N.; Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  18. Ultrasound Current Source Density Imaging of the Cardiac Activation Wave Using a Clinical Cardiac Catheter

    PubMed Central

    Qin, Yexian; Li, Qian; Ingram, Pier; Barber, Christy; Liu, Zhonglin

    2015-01-01

    Ultrasound current source density imaging (UCSDI), based on the acoustoelectric (AE) effect, is a noninvasive method for mapping electrical current in 4-D (space + time). This technique potentially overcomes limitations with conventional electrical mapping procedures typically used during treatment of sustained arrhythmias. However, the weak AE signal associated with the electrocardiogram is a major challenge for advancing this technology. In this study, we examined the effects of the electrode configuration and ultrasound frequency on the magnitude of the AE signal and quality of UCSDI using a rabbit Langendorff heart preparation. The AE signal was much stronger at 0.5 MHz (2.99 μV/MPa) than 1.0 MHz (0.42 μV/MPa). Also, a clinical lasso catheter placed on the epicardium exhibited excellent sensitivity without penetrating the tissue. We also present, for the first time, 3-D cardiac activation maps of the live rabbit heart using only one pair of recording electrodes. Activation maps were used to calculate the cardiac conduction velocity for atrial (1.31 m/s) and apical (0.67 m/s) pacing. This study demonstrated that UCSDI is potentially capable of real-time 3-D cardiac activation wave mapping, which would greatly facilitate ablation procedures for treatment of arrhythmias. PMID:25122512

  19. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

    NASA Astrophysics Data System (ADS)

    Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

    2012-10-01

    Ultrasound current source density imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and seven cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012%/MPa, similar to the measurement of K in physiological saline (0.034±0.003%/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias.

  20. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

    PubMed Central

    Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

    2012-01-01

    Ultrasound Current Source Density Imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and 7 cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012 %/MPa, similar to the measurement of K in physiologic saline (0.034±0.003 %/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias. PMID:22954500

  1. A 20 Mfps high frame-depth CMOS burst-mode imager with low power in-pixel NMOS-only passive amplifier

    NASA Astrophysics Data System (ADS)

    Wu, L.; San Segundo Bello, D.; Coppejans, P.; Craninckx, J.; Wambacq, P.; Borremans, J.

    2017-02-01

    This paper presents a 20 Mfps 32 × 84 pixels CMOS burst-mode imager featuring high frame depth with a passive in-pixel amplifier. Compared to the CCD alternatives, CMOS burst-mode imagers are attractive for their low power consumption and integration of circuitry such as ADCs. Due to storage capacitor size and its noise limitations, CMOS burst-mode imagers usually suffer from a lower frame depth than CCD implementations. In order to capture fast transitions over a longer time span, an in-pixel CDS technique has been adopted to reduce the required memory cells for each frame by half. Moreover, integrated with in-pixel CDS, an in-pixel NMOS-only passive amplifier alleviates the kTC noise requirements of the memory bank allowing the usage of smaller capacitors. Specifically, a dense 108-cell MOS memory bank (10fF/cell) has been implemented inside a 30μm pitch pixel, with an area of 25 × 30μm2 occupied by the memory bank. There is an improvement of about 4x in terms of frame depth per pixel area by applying in-pixel CDS and amplification. With the amplifier's gain of 3.3, an FD input-referred RMS noise of 1mV is achieved at 20 Mfps operation. While the amplification is done without burning DC current, including the pixel source follower biasing, the full pixel consumes 10μA at 3.3V supply voltage at full speed. The chip has been fabricated in imec's 130nm CMOS CIS technology.

  2. An interpretation of induced electric currents in long pipelines caused by natural geomagnetic sources of the upper atmosphere

    USGS Publications Warehouse

    Campbell, W.H.

    1986-01-01

    Electric currents in long pipelines can contribute to corrosion effects that limit the pipe's lifetime. One cause of such electric currents is the geomagnetic field variations that have sources in the Earth's upper atmosphere. Knowledge of the general behavior of the sources allows a prediction of the occurrence times, favorable locations for the pipeline effects, and long-term projections of corrosion contributions. The source spectral characteristics, the Earth's conductivity profile, and a corrosion-frequency dependence limit the period range of the natural field changes that affect the pipe. The corrosion contribution by induced currents from geomagnetic sources should be evaluated for pipelines that are located at high and at equatorial latitudes. At midlatitude locations, the times of these natural current maxima should be avoided for the necessary accurate monitoring of the pipe-to-soil potential. ?? 1986 D. Reidel Publishing Company.

  3. Variability of Surface pollutants and aerosol concentration over Abu Dhabi, UAE - sources, transport and current levels

    NASA Astrophysics Data System (ADS)

    Phanikumar, Devulapalli V.; Basha, Ghouse; Ouarda, Taha B. M. J.

    2015-04-01

    pollutants are in contrast with the diurnal pattern of wind speed as evident from the previous observations. Wind rose diagram of pollutants reveal that the dominant source directions are scattered from northwesterly to southwesterly. Our results (2011-13) are compared with earlier observations from the same region (2007-08) and no alarming differences were observed in the pollutant levels. Our observations are discussed in the light of current understanding of pollutants sources over this region.

  4. Modeling of Single Event Transients With Dual Double-Exponential Current Sources: Implications for Logic Cell Characterization

    NASA Astrophysics Data System (ADS)

    Black, Dolores A.; Robinson, William H.; Wilcox, Ian Z.; Limbrick, Daniel B.; Black, Jeffrey D.

    2015-08-01

    Single event effects (SEE) are a reliability concern for modern microelectronics. Bit corruptions can be caused by single event upsets (SEUs) in the storage cells or by sampling single event transients (SETs) from a logic path. An accurate prediction of soft error susceptibility from SETs requires good models to convert collected charge into compact descriptions of the current injection process. This paper describes a simple, yet effective, method to model the current waveform resulting from a charge collection event for SET circuit simulations. The model uses two double-exponential current sources in parallel, and the results illustrate why a conventional model based on one double-exponential source can be incomplete. A small set of logic cells with varying input conditions, drive strength, and output loading are simulated to extract the parameters for the dual double-exponential current sources. The parameters are based upon both the node capacitance and the restoring current (i.e., drive strength) of the logic cell.

  5. Multiband CMOS sensor simplify FPA design

    NASA Astrophysics Data System (ADS)

    Wang, Weng Lyang B.; Ling, Jer

    2015-10-01

    Push broom multi-band Focal Plane Array (FPA) design needs to consider optics, image sensor, electronic, mechanic as well as thermal. Conventional FPA use two or several CCD device as an image sensor. The CCD image sensor requires several high speed, high voltage and high current clock drivers as well as analog video processors to support their operation. Signal needs to digitize using external sample / hold and digitized circuit. These support circuits are bulky, consume a lot of power, must be shielded and placed in close to the CCD to minimize the introduction of unwanted noise. The CCD also needs to consider how to dissipate power. The end result is a very complicated FPA and hard to make due to more weighs and draws more power requiring complex heat transfer mechanisms. In this paper, we integrate microelectronic technology and multi-layer soft / hard Printed Circuit Board (PCB) technology to design electronic portion. Since its simplicity and integration, the optics, mechanic, structure and thermal design will become very simple. The whole FPA assembly and dis-assembly reduced to a few days. A multi-band CMOS Sensor (dedicated as C468) was used for this design. The CMOS Sensor, allow for the incorporation of clock drivers, timing generators, signal processing and digitization onto the same Integrated Circuit (IC) as the image sensor arrays. This keeps noise to a minimum while providing high functionality at reasonable power levels. The C468 is a first Multiple System-On-Chip (MSOC) IC. This device used our proprietary wafer butting technology and MSOC technology to combine five long sensor arrays into a size of 120 mm x 23.2 mm and 155 mm x 60 mm for chip and package, respectively. The device composed of one Panchromatic (PAN) and four different Multi- Spectral (MS) sensors. Due to its integration on the electronic design, a lot of room is clear for the thermal design. The optical and mechanical design is become very straight forward. The flight model FPA

  6. Swap intensified WDR CMOS module for I2/LWIR fusion

    NASA Astrophysics Data System (ADS)

    Ni, Yang; Noguier, Vincent

    2015-05-01

    The combination of high resolution visible-near-infrared low light sensor and moderate resolution uncooled thermal sensor provides an efficient way for multi-task night vision. Tremendous progress has been made on uncooled thermal sensors (a-Si, VOx, etc.). It's possible to make a miniature uncooled thermal camera module in a tiny 1cm3 cube with <1W power consumption. For silicon based solid-state low light CCD/CMOS sensors have observed also a constant progress in terms of readout noise, dark current, resolution and frame rate. In contrast to thermal sensing which is intrinsic day&night operational, the silicon based solid-state sensors are not yet capable to do the night vision performance required by defense and critical surveillance applications. Readout noise, dark current are 2 major obstacles. The low dynamic range at high sensitivity mode of silicon sensors is also an important limiting factor, which leads to recognition failure due to local or global saturations & blooming. In this context, the image intensifier based solution is still attractive for the following reasons: 1) high gain and ultra-low dark current; 2) wide dynamic range and 3) ultra-low power consumption. With high electron gain and ultra low dark current of image intensifier, the only requirement on the silicon image pickup device are resolution, dynamic range and power consumption. In this paper, we present a SWAP intensified Wide Dynamic Range CMOS module for night vision applications, especially for I2/LWIR fusion. This module is based on a dedicated CMOS image sensor using solar-cell mode photodiode logarithmic pixel design which covers a huge dynamic range (> 140dB) without saturation and blooming. The ultra-wide dynamic range image from this new generation logarithmic sensor can be used directly without any image processing and provide an instant light accommodation. The complete module is slightly bigger than a simple ANVIS format I2 tube with <500mW power consumption.

  7. Source Indexing in Science Journals and Indexing Services: A Survey of Current Practices.

    ERIC Educational Resources Information Center

    Diodato, Virgil; Pearson, Karen

    1986-01-01

    Study of state of source indexing (indexing data published simultaneously with articles they represent) examines aspects of 685 science journals: science fields using source indexing; source indexing formats; assignment of indexing terms from controlled vocabularies; suppliers of indexing (authors, editors, indexers); use of source indexing by…

  8. Novel MSVPWM to reduce the inductor current ripple for Z-source inverter in electric vehicle applications.

    PubMed

    Zhang, Qianfan; Dong, Shuai; Xue, Ping; Zhou, Chaowei; Cheng, ShuKang

    2014-01-01

    A novel modified space vector pulse width modulation (MSVPWM) strategy for Z-Source inverter is presented. By rearranging the position of shoot-through states, the frequency of inductor current ripple is kept constant. Compared with existing MSVPWM strategies, the proposed approach can reduce the maximum inductor current ripple. So the volume of Z-source network inductor can be designed smaller, which brings the beneficial effect on the miniaturization of the electric vehicle controller. Theoretical findings in the novel MSVPWM for Z-Source inverter have been verified by experiment results.

  9. Novel MSVPWM to Reduce the Inductor Current Ripple for Z-Source Inverter in Electric Vehicle Applications

    PubMed Central

    Zhang, Qianfan; Dong, Shuai; Xue, Ping; Zhou, Chaowei; Cheng, ShuKang

    2014-01-01

    A novel modified space vector pulse width modulation (MSVPWM) strategy for Z-Source inverter is presented. By rearranging the position of shoot-through states, the frequency of inductor current ripple is kept constant. Compared with existing MSVPWM strategies, the proposed approach can reduce the maximum inductor current ripple. So the volume of Z-source network inductor can be designed smaller, which brings the beneficial effect on the miniaturization of the electric vehicle controller. Theoretical findings in the novel MSVPWM for Z-Source inverter have been verified by experiment results. PMID:24883412

  10. Flexible packaging and integration of CMOS IC with elastomeric microfluidics

    NASA Astrophysics Data System (ADS)

    Zhang, Bowei; Dong, Quan; Korman, Can E.; Li, Zhenyu; Zaghloul, Mona E.

    2013-05-01

    We have demonstrated flexible packaging and integration of CMOS IC chips with PDMS microfluidics. Microfluidic channels are used to deliver both liquid samples and liquid metals to the CMOS die. The liquid metals are used to realize electrical interconnects to the CMOS chip. As a demonstration we integrated a CMOS magnetic sensor die and matched PDMS microfluidic channels in a flexible package. The packaged system is fully functional under 3cm bending radius. The flexible integration of CMOS ICs with microfluidics enables previously unavailable flexible CMOS electronic systems with fluidic manipulation capabilities, which hold great potential for wearable health monitoring, point-of-care diagnostics and environmental sensing.

  11. 180 Degree Hybrid (Rat-Race) Junction on CMOS Grade Silicon with a Polyimide Interface Layer

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Papapolymerou, John

    2003-01-01

    180-degree hybrid junctions can be used to equally divide power between two output ports with either a 0 or 180-degree phase difference. Alternatively, they can be used to combine signals from two sources and output a sum and difference signal. The main limitation of implementing; these on CMOS grade silicon is the high loss associated with the substrate. In this paper, we present a low loss 180-degree hybrid junction on CMOS grade (15 omega-cm) silicon with a polyimide interface layer for the first time. The divider utilizes Finite Ground Coplanar (FGC) line technology, and operates at a center frequency of 15 GIIz.

  12. 180 Degree Hybrid (Rat-Race) Junction on CMOS Grade Silicon with a Polyimide Interface Layer

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Papapolymerou, John

    2003-01-01

    180-degree hybrid junctions can be used to equally divide power between two output ports with either a 0 or 180-degree phase difference. Alternatively, they can be used to combine signals from two sources and output a sum and difference signal. The main limitation of implementing; these on CMOS grade silicon is the high loss associated with the substrate. In this paper, we present a low loss 180-degree hybrid junction on CMOS grade (15 omega-cm) silicon with a polyimide interface layer for the first time. The divider utilizes Finite Ground Coplanar (FGC) line technology, and operates at a center frequency of 15 GIIz.

  13. Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition.

    PubMed Central

    Clark, Deborah A

    2004-01-01

    How tropical rainforests are responding to the ongoing global changes in atmospheric composition and climate is little studied and poorly understood. Although rising atmospheric carbon dioxide (CO2) could enhance forest productivity, increased temperatures and drought are likely to diminish it. The limited field data have produced conflicting views of the net impacts of these changes so far. One set of studies has seemed to point to enhanced carbon uptake; however, questions have arisen about these findings, and recent experiments with tropical forest trees indicate carbon saturation of canopy leaves and no biomass increase under enhanced CO2. Other field observations indicate decreased forest productivity and increased tree mortality in recent years of peak temperatures and drought (strong El Niño episodes). To determine current climatic responses of forests around the world tropics will require careful annual monitoring of ecosystem performance in representative forests. To develop the necessary process-level understanding of these responses will require intensified experimentation at the whole-tree and stand levels. Finally, a more complete understanding of tropical rainforest carbon cycling is needed for determining whether these ecosystems are carbon sinks or sources now, and how this status might change during the next century. PMID:15212097

  14. Estimation of population firing rates and current source densities from laminar electrode recordings.

    PubMed

    Pettersen, Klas H; Hagen, Espen; Einevoll, Gaute T

    2008-06-01

    This model study investigates the validity of methods used to interpret linear (laminar) multielectrode recordings. In computer experiments extracellular potentials from a synaptically activated population of about 1,000 pyramidal neurons are calculated using biologically realistic compartmental neuron models combined with electrostatic forward modeling. The somas of the pyramidal neurons are located in a 0.4 mm high and wide columnar cylinder, mimicking a stimulus-evoked layer-5 population in a neocortical column. Current-source density (CSD) analysis of the low-frequency part (<500 Hz) of the calculated potentials (local field potentials, LFP) based on the 'inverse' CSD method is, in contrast to the 'standard' CSD method, seen to give excellent estimates of the true underlying CSD. The high-frequency part (>750 Hz) of the potentials (multi-unit activity, MUA) is found to scale approximately as the population firing rate to the power 3/4 and to give excellent estimates of the underlying population firing rate for trial-averaged data. The MUA signal is found to decay much more sharply outside the columnar populations than the LFP.

  15. Current Source Mapping by Spontaneous MEG and ECoG in Piglets Model

    PubMed Central

    Gao, Lin; Wang, Jue; Stephen, Julia; Zhang, Tongsheng

    2016-01-01

    The previous research reveals the presence of relatively strong spatial correlations from spontaneous activity over cortex in Electroencephalography (EEG) and Magnetoencephalography (MEG) measurement. A critical obstacle in MEG current source mapping is that strong background activity masks the relatively weak local information. In this paper, the hypothesis is that the dominant components of this background activity can be captured by the first Principal Component (PC) after employing Principal Component Analysis (PCA), thus discarding the first PC before the back projection would enhance the exposure of the information carried by a subset of sensors that reflects the local neuronal activity. By detecting MEG signals densely (one measurement per 2×2 mm2) in three piglets neocortical models over an area of 18×26 mm2 with a special shape of lesion by means of a μSQUID, this basic idea was demonstrated by the fact that a strong activity could be imaged in the lesion region after removing the first PC in Delta, Theta and Alpha band, while the original recordings did not show such activity clearly. Thus, the PCA decomposition can be employed to expose the local activity, which is around the lesion in the piglets’ neocortical models, by removing the dominant components of the background activity. PMID:27570537

  16. Quantifying sources and sinks of trace gases using space-borne measurements: current and future science.

    PubMed

    Palmer, Paul I

    2008-12-28

    We have been observing the Earth's upper atmosphere from space for several decades, but only over the past decade has the necessary technology begun to match our desire to observe surface air pollutants and climate-relevant trace gases in the lower troposphere, where we live and breathe. A new generation of Earth-observing satellites, capable of probing the lower troposphere, are already orbiting hundreds of kilometres above the Earth's surface with several more ready for launch or in the planning stages. Consequently, this is one of the most exciting times for the Earth system scientists who study the countless current-day physical, chemical and biological interactions between the Earth's land, ocean and atmosphere. First, I briefly review the theory behind measuring the atmosphere from space, and how these data can be used to infer surface sources and sinks of trace gases. I then present some of the science highlights associated with these data and how they can be used to improve fundamental understanding of the Earth's climate system. I conclude the paper by discussing the future role of satellite measurements of tropospheric trace gases in mitigating surface air pollution and carbon trading.

  17. Reduction of ocular artefacts in source current density brain mappings by ARX2 filtering.

    PubMed

    Filligoi, G C; Capitanio, L; Babiloni, F; Fattorini, L; Urbano, A; Cerutti, S

    1995-06-01

    Sweep by sweep analysis of event-related potentials (ERP) of the human scalp represents a reliable tool for both the diagnosis of neurologic diseases and the study of the central nervous system during cognitive tasks. The off-line procedure based on stochastic parametric identification and filtering herewith described, allows an accurate analysis of single-sweep ERP and a drastic reduction of ocular artefacts variously propagating through the skull. Moreover, the spatial distribution of the recorded ERP in bidimensional form was enhanced by using the Laplacian operator in order to get an estimate of the source current density (SCD) flow from the skull into the scalp. Complete single-trial signals were filtered according to an autoregressive model of signal generation with 2 exogenous inputs (ARX2). The ARX2 procedure models the recorded signal as the sum of three signals: (a) the background EEG activity, modelled as an autoregressive process driven by a white noise; (b) a filtered version of a reference signal carrying the average information contained in each sweep; (c) a signal due to the ocular artefact propagation. The evaluation of the effect of artefact suppression on those channels close to the eyes was compared with standard ordinary least squares method (OLS) based on a linear model of the influence of EOG on ERP. Finally, the better results obtainable through ARX filtering on sweep-by-sweep brain mappings are also presented.

  18. Characteristics of cold atmospheric plasma source based on low-current pulsed discharge with coaxial electrodes

    NASA Astrophysics Data System (ADS)

    Bureyev, O. A.; Surkov, Yu S.; Spirina, A. V.

    2017-05-01

    This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

  19. Development of low read noise high conversion gain CMOS image sensor for photon counting level imaging

    NASA Astrophysics Data System (ADS)

    Seo, Min-Woong; Kawahito, Shoji; Kagawa, Keiichiro; Yasutomi, Keita

    2016-05-01

    A CMOS image sensor with deep sub-electron read noise and high pixel conversion gain has been developed. Its performance is recognized through image outputs from an area image sensor, confirming the capability of photoelectroncounting- level imaging. To achieve high conversion gain, the proposed pixel has special structures to reduce the parasitic capacitances around FD node. As a result, the pixel conversion gain is increased due to the optimized FD node capacitance, and the noise performance is also improved by removing two noise sources from power supply. For the first time, high contrast images from the reset-gate-less CMOS image sensor, with less than 0.3e- rms noise level, have been generated at an extremely low light level of a few electrons per pixel. In addition, the photon-counting capability of the developed CMOS imager is demonstrated by a measurement, photoelectron-counting histogram (PCH).

  20. A CMOS Smart Temperature and Humidity Sensor with Combined Readout

    PubMed Central

    Eder, Clemens; Valente, Virgilio; Donaldson, Nick; Demosthenous, Andreas

    2014-01-01

    A fully-integrated complementary metal-oxide semiconductor (CMOS) sensor for combined temperature and humidity measurements is presented. The main purpose of the device is to monitor the hermeticity of micro-packages for implanted integrated circuits and to ensure their safe operation by monitoring the operating temperature and humidity on-chip. The smart sensor has two modes of operation, in which either the temperature or humidity is converted into a digital code representing a frequency ratio between two oscillators. This ratio is determined by the ratios of the timing capacitances and bias currents in both oscillators. The reference oscillator is biased by a current whose temperature dependency is complementary to the proportional to absolute temperature (PTAT) current. For the temperature measurement, this results in an exceptional normalized sensitivity of about 0.77%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor, whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.055%/% RH. For comparison, two versions of the humidity sensor with an area of either 0.2 mm2 or 1.2 mm2 were fabricated in a commercial 0.18 μm CMOS process. The on-chip readout electronics operate from a 5 V power supply and consume a current of approximately 85 μA. PMID:25230305

  1. A CMOS smart temperature and humidity sensor with combined readout.

    PubMed

    Eder, Clemens; Valente, Virgilio; Donaldson, Nick; Demosthenous, Andreas

    2014-09-16

    A fully-integrated complementary metal-oxide semiconductor (CMOS) sensor for combined temperature and humidity measurements is presented. The main purpose of the device is to monitor the hermeticity of micro-packages for implanted integrated circuits and to ensure their safe operation by monitoring the operating temperature and humidity on-chip. The smart sensor has two modes of operation, in which either the temperature or humidity is converted into a digital code representing a frequency ratio between two oscillators. This ratio is determined by the ratios of the timing capacitances and bias currents in both oscillators. The reference oscillator is biased by a current whose temperature dependency is complementary to the proportional to absolute temperature (PTAT) current. For the temperature measurement, this results in an exceptional normalized sensitivity of about 0.77%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor, whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.055%/% RH. For comparison, two versions of the humidity sensor with an area of either 0.2 mm2 or 1.2 mm2 were fabricated in a commercial 0.18 μm CMOS process. The on-chip readout electronics operate from a 5 V power supply and consume a current of approximately 85 µA.

  2. New package for CMOS sensors

    NASA Astrophysics Data System (ADS)

    Diot, Jean-Luc; Loo, Kum Weng; Moscicki, Jean-Pierre; Ng, Hun Shen; Tee, Tong Yan; Teysseyre, Jerome; Yap, Daniel

    2004-02-01

    Cost is the main drawback of existing packages for C-MOS sensors (mainly CLCC family). Alternative packages are thus developed world-wide. And in particular, S.T.Microelectronics has studied a low cost alternative packages based on QFN structure, still with a cavity. Intensive work was done to optimize the over-molding operation forming the cavity onto a metallic lead-frame (metallic lead-frame is a low cost substrate allowing very good mechanical definition of the final package). Material selection (thermo-set resin and glue for glass sealing) was done through standard reliability tests for cavity packages (Moisture Sensitivity Level 3 followed by temperature cycling, humidity storage and high temperature storage). As this package concept is new (without leads protruding the molded cavity), the effect of variation of package dimensions, as well as board lay-out design, are simulated on package life time (during temperature cycling, thermal mismatch between board and package leads to thermal fatigue of solder joints). These simulations are correlated with an experimental temperature cycling test with daisy-chain packages.

  3. Current Methodologies in Preparing Mobile Source Port-Related Emission Inventories Final Report April 2009

    EPA Pesticide Factsheets

    This report focuses on mobile emission sources at ports, including oceangoing vessels (OGVs), harbor craft, and cargo handling equipment (CHE), as well as other land-side mobile emission sources at ports, such as locomotives and on-highway vehicles.

  4. Characterizing Materials Sources and Sinks; Current Approaches: Part II. Chemical and Physical Characterization

    EPA Science Inventory

    The paper discusses methods for characterizing chemical emissions from material sources, including laboratory, dynamic chamber, and full-scale studies. Indoor sources and their interaction with sinks play a major role in determining indoor air quality (IAQ). Techniques for evalua...

  5. Recent progress and development of a speedster-EXD: a new event-triggered hybrid CMOS x-ray detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher V.; Falcone, Abraham D.; Prieskorn, Zachary R.; Burrows, David N.

    2015-08-01

    We present the characterization of a new event-driven X-ray hybrid CMOS detector developed by Penn State University in collaboration with Teledyne Imaging Sensors. Along with its low susceptibility to radiation damage, low power consumption, and fast readout time to avoid pile-up, the Speedster-EXD has been designed with the capability to limit its readout to only those pixels containing charge, thus enabling even faster effective frame rates. The threshold for the comparator in each pixel can be set by the user so that only pixels with signal above the set threshold are read out. The Speedster-EXD hybrid CMOS detector also has two new in-pixel features that reduce noise from known noise sources: (1) a low-noise, high-gain CTIA amplifier to eliminate crosstalk from interpixel capacitance (IPC) and (2) in-pixel CDS subtraction to reduce kTC noise. We present the read noise, dark current, IPC, energy resolution, and gain variation measurements of one Speedster-EXD detector.

  6. DESIGN OF 2.4 GHZ CMOS DIRECT CONVERSION LNA AND MIXER COMBINATION FOR WIRLESS DATA LINK TRANSCEIVER.

    SciTech Connect

    ZHAO, D.; OCONNOR, P.

    2002-04-10

    Three LNA and mixer combinations in 0.6{micro}m and 0.4{micro}m standard CMOS processes for direct-conversion receiver of 2.4GHz ISM band short-range wireless data-link applications are described in this paper. Taking low power dissipation as first consideration, these designs, employing differential common-source LNA and double balanced mixer architectures, achieve total conversion gain as high as 42.4dB, DSB noise figure as low as 9.5dB, output-referred IP3 as high as of 21.3dBm at about 4mA DC current consumption. This proves it is possible to apply standard CMOS process to implement receiver front-end with low power dissipation for this kind of application, but gain changeable LNA is needed to combat the dominant flicker noise of the mixer in order to achieve acceptable sensitivity and dynamic range at the same time.

  7. The DUV Stability of Superlattice-Doped CMOS Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hoenk, M. E.; Carver, A. G.; Jones, T.; Dickie, M.; Cheng, P.; Greer, H. F.; Nikzad, S.; Sgro, J.; Tsur, S.

    2013-01-01

    JPL and Alacron have recently developed a high performance, DUV camera with a superlattice doped CMOS imaging detector. Supperlattice doped detectors achieve nearly 100% internal quantum efficiency in the deep and far ultraviolet, and a single layer, Al2O3 antireflection coating enables 64% external quantum efficiency at 263nm. In lifetime tests performed at Applied Materials using 263 nm pulsed, solid state and 193 nm pulsed excimer laser, the quantum efficiency and dark current of the JPL/Alacron camera remained stable to better than 1% precision during long-term exposure to several billion laser pulses, with no measurable degradation, no blooming and no image memory at 1000 fps.

  8. REVIEW AND EVALUATION OF CURRENT METHODS AND USER NEEDS FOR OTHER STATIONARY COMBUSTION SOURCES

    EPA Science Inventory

    The report gives results of Phase 1 of an effort to develop improved methodologies for estimating area source emissions of air pollutants from stationary combustion sources. The report (1) evaluates Area and Mobile Source (AMS) subsystem methodologies; (2) compares AMS results w...

  9. Open Access, Open Source and Digital Libraries: A Current Trend in University Libraries around the World

    ERIC Educational Resources Information Center

    Krishnamurthy, M.

    2008-01-01

    Purpose: The purpose of this paper is to describe the open access and open source movement in the digital library world. Design/methodology/approach: A review of key developments in the open access and open source movement is provided. Findings: Open source software and open access to research findings are of great use to scholars in developing…

  10. Open Access, Open Source and Digital Libraries: A Current Trend in University Libraries around the World

    ERIC Educational Resources Information Center

    Krishnamurthy, M.

    2008-01-01

    Purpose: The purpose of this paper is to describe the open access and open source movement in the digital library world. Design/methodology/approach: A review of key developments in the open access and open source movement is provided. Findings: Open source software and open access to research findings are of great use to scholars in developing…

  11. Transmission and reflective ultrasound images using PE-CMOS sensor array

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Liu, Chu Chuan; Freedman, Matthew T.; Kula, John; Lasser, Bob; Lasser, Marvin E.; Wang, Yue

    2005-04-01

    The purpose of this study is to investigate the imaging capability of a CMOS (PE-CMOS) ultrasound sensing array coated with piezoelectric material. There are three main components in the laboratory setup: (1) a transducer operated at 3.5MHz-7MHz frequency generating unfocused ultrasound plane waves, (2) an acoustic compound lens that collects the energy and focuses ultrasound signals onto the detector array, and (3) a PE-CMOS ultrasound sensing array (Model I400, Imperium Inc. Silver Spring, MD) that receives the ultrasound and converts the energy to analog voltage followed by a digital conversion. The PE-CMOS array consists of 128×128 pixel elements with 85μm per pixel. The major improvement of the new ultrasound sensor array has been in its dynamic range. We found that the current PE-CMOS ultrasound sensor (Model I400) possesses a dynamic range up to 70dB. The system can generate ultrasound attenuation images of soft tissues which are similar to digital images obtained from an x-ray projection system. In the paper, we also show that the prototype system can image bone fractures using reflective geometry.

  12. Characteristics of Various Photodiode Structures in CMOS Technology with Monolithic Signal Processing Electronics

    SciTech Connect

    Mukhopadhyay, Sourav; Chandratre, V. B.; Sukhwani, Menka; Pithawa, C. K.

    2011-10-20

    Monolithic optical sensor with readout electronics are needed in optical communication, medical imaging and scintillator based gamma spectroscopy system. This paper presents the design of three different CMOS photodiode test structures and two readout channels in a commercial CMOS technology catering to the need of nuclear instrumentation. The three photodiode structures each of 1 mm{sup 2} with readout electronics are fabricated in 0.35 um, 4 metal, double poly, N-well CMOS process. These photodiode structures are based on available P-N junction of standard CMOS process i.e. N-well/P-substrate, P+/N-well/P-substrate and inter-digitized P+/N-well/P-substrate. The comparisons of typical characteristics among three fabricated photo sensors are reported in terms of spectral sensitivity, dark current and junction capacitance. Among the three photodiode structures N-well/P-substrate photodiode shows higher spectral sensitivity compared to the other two photodiode structures. The inter-digitized P+/N-well/P-substrate structure has enhanced blue response compared to N-well/P-substrate and P+/N-well/P-substrate photodiode. Design and test results of monolithic readout electronics, for three different CMOS photodiode structures for application related to nuclear instrumentation, are also reported.

  13. Characterization of high resolution CMOS monolithic active pixel detector in SOI technology

    NASA Astrophysics Data System (ADS)

    Ahmed, M. I.; Arai, Y.; Glab, S.; Idzik, M.; Kapusta, P.; Miyoshi, T.; Takeda, A.; Turala, M.

    2015-05-01

    Novel CMOS monolithic pixel detectors designed at KEK and fabricated at Lapis Semiconductor in 0.2 μm Silicon-on-Insulator (SOI) technology are presented. A thin layer of silicon oxide separates high and low resistivity silicon layers, allowing for optimization of design of detector and readout parts. Shallow wells buried under the oxide in the detector part screen the entire pixel electronics from electrical field applied to the detector. Several integration type SOI pixel detectors have been developed with pixel sizes 8-20 μm. The general features of 14 × 14 μm2 detectors designed on different wafers (CZ-n, FZ-n and FZ-p) were measured and compared. The detector performance was studied under irradiation with visible and infra-red laser, and also X-ray ionizing source. Using X-rays from an Am-241 source the noise of readout electronics was measured at different working conditions, showing the ENC in the range of 88-120 e-. The pixel current was calculated from average DC pedestal shift while varying the pixel integration time. The operation of the detector was studied under partial and full depletion conditions. The effects of temperature and detector bias voltage on noise and leakage current were studied. Characteristics of an ADC integrated in the front-end chip are also presented.

  14. Optical waveguide taps on silicon CMOS circuits

    NASA Astrophysics Data System (ADS)

    Stenger, Vincent E.; Beyette, Fred R., Jr.

    2000-11-01

    As silicon CMOS circuit technology is scaled beyond the GHz range, both chipmakers and board makers face increasingly difficult challenges in implementing high speed metal interconnects. Metal traces are limited in density-speed performance due to the skin effect, electrical conductivity, and cross talk. Optical based interconnects have higher available bandwidth by virtue of the extremely high carrier frequencies of optical signals (> 100 THz). For this work, an effort has been made to determine an optimal optical tap receiver design for integration with commercial CMOS processes. Candidate waveguide tap technologies were considered in terms of optical loss, bandwidth, economy, and CMOS process compatibility. A new device, which is based on a variation of the multimode interference effect, has been found to be especially promising. BeamProp simulation results show nearly zero excess optical loss for the design, and up to 70% coupling into a 25 micrometer traveling wave CMOS photodetector device. Single-mode waveguides make the design readily compatible with wavelength multiplexing/demultiplexing elements. Polymer waveguide materials are targeted for fabrication due to planarization properties, low cost, broad index control, and poling abilities for modulation/tuning functions. Low cost, silicon CMOS based processing makes the new tap technology especially suitable for computer chip and board level interconnects, as well as metro fiber-to-the- home/desk telecommunications applications.

  15. Functional interconnections between CA3 and the dentate gyrus revealed by current source density analysis.

    PubMed

    Wu, K; Canning, K J; Leung, L S

    1998-01-01

    The physiological interactions between the dentate gyrus (DG) and CA3 were studied in urethane-anesthetized rats by using field potential recording and current source density (CSD) analysis. Stimulation of CA3b resulted in a short-latency (<2.5-ms onset latency) antidromic population spike in both the DG and CA3c. An excitation (current sink) at the middle molecular layer (MML) was observed at 3-ms latency, possibly mediated by the backfiring of perforant path fibers that projected to both DG and CA3. CA3 stimulation also resulted in a sink at the dendritic layers of CA3c, which was likely mediated by excitatory CA3 recurrent collaterals. It was inferred that the DG was excited at the inner molecular layer (IML) after stimulation near the CA3b/CA3c border. This IML excitation (sink) probably resulted from orthodromic CA3 or hilar projections to the IML and not from mossy fiber backfiring. The IML and the CA3c dendritic sinks were blocked by an intracerebroventricular injection of a non-N-methyl-D-aspartate receptor antagonist, 6-cyano-7-nitroquinoxaline-2, 3-dione, but not by a gamma-aminobutyric acid type A (GABA(A)) receptor antagonist, bicuculline. CA3b stimulation evoked population spike bursts (3-7-ms latency) in both DG and CA3c when GABA(A) inhibition was suppressed by bicuculline, thus confirming that the excitatory afferents project from CA3b to DG and CA3c. A CA3 conditioning stimulus pulse given 30-200 ms before a perforant-path test pulse increased the amplitude of the perforant-path-evoked DG population spike (as compared with the test response without conditioning). After a moderate-intensity stimulation of CA3, a late (<20-ms latency) excitation of the MML of the DG was found. The late DG excitation was blocked by procaine injection at the medial perforant path, suggesting its origin from the medial entorhinal cortex. In conclusion, rich interactions between CA3 and other hippocampal structures were studied quantitatively by CSD analysis in vivo. We

  16. EEG current source density and the phenomenology of the default network.

    PubMed

    Cannon, Rex L; Baldwin, Debora R

    2012-10-01

    In recent years, there has been an increasing line of research dedicated to the investigation of the default mode network (DMN) of the brain and resting state networks. However, the mental activity of the DMN has not been rigorously assessed to date. The specific aims of the current study were 2-fold: First, we sought to determine whether the current source density (CSD) levels in the DMN would correspond to other neuroimaging techniques. Second, we sought to understand the subjective mental activity of the DMN during baseline recordings. This study was conducted with 63 nonclinical participants, 34 female and 29 males with a mean age of 19.2 years (standard deviation = 2.0). The participants were recorded in 8 conditions. First, 4-minute eyes-closed baseline (ECB) and eyes-opened baseline (EOB) were obtained. The participants then completed 3 assessment instruments and 3 image conditions while the electroencephalography (EEG) was continuously recorded. Participants completed subjective reports for baselines and image conditions. These were rated by 3 independent raters and compared for reliability using a random effects model with an absolute agreement definition. The mean CSD between all conditions differed significantly, in many but not all regions of interest in the DMN. Interestingly, as suggested by other studies, the DMN appears preferential to self-relevant, self-specific, or self-perceptive processes. The reliability analyses show α for interrater agreement for ECB at .95 and EOB at .96. The subjective reports obtained from the participants regarding the mental activities employed during baseline recordings correspond to attentional and self-regulatory processes, which may also implicate the resting state or DMN as playing a direct role in the maintenance of a complex behavior (eg, being still, attending, and self-regulating). Thus, attention and self-regulation constitute the phenomenology of the resting state (DMN) in this study. The results also

  17. Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter

    NASA Astrophysics Data System (ADS)

    Li, Qian

    Ultrasound Current Source Density Imaging (UCSDI) is a noninvasive modality for mapping electrical activities in the body (brain and heart) in 4-dimensions (space + time). Conventional cardiac mapping technologies for guiding the radiofrequency ablation procedure for treatment of cardiac arrhythmias have certain limitations. UCSDI can potentially overcome these limitations and enhance the electrophysiology mapping of the heart. UCSDI exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity. When an ultrasound beam intersects a current path in a material, the local resistivity of the material is modulated by the ultrasonic pressure, and a change in voltage signal can be detected based on Ohm's Law. The degree of modulation is determined by the AE interaction constant K. K is a fundamental property of any type of material, and directly affects the amplitude of the AE signal detected in UCSDI. UCSDI requires detecting a small AE signal associated with electrocardiogram. So sensitivity becomes a major challenge for transferring UCSDI to the clinic. This dissertation will determine the limits of sensitivity and resolution for UCSDI, balancing the tradeoff between them by finding the optimal parameters for electrical cardiac mapping, and finally test the optimized system in a realistic setting. This work begins by describing a technique for measuring K, the AE interaction constant, in ionic solution and biological tissue, and reporting the value of K in excised rabbit cardiac tissue for the first time. K was found to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart tissue, K was determined to be 0.041 +/- 0.012 %/MPa, similar to the measurement of K in physiologic saline: 0.034 +/- 0.003 %/MPa. Next, this dissertation investigates the sensitivity limit of UCSDI by quantifying the relation

  18. New generation CMOS 2D imager evaluation and qualification for semiconductor inspection applications

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Hart, Darcy

    2013-09-01

    Semiconductor fabrication process defect inspection industry is always driven by inspection resolution and through-put. With fabrication technology node advances to 2X ~1Xnm range, critical macro defect size approaches to typical CMOS camera pixel size range, therefore single pixel defect detection technology becomes more and more essential, which is fundamentally constrained by camera performance. A new evaluation model is presented here to specifically describe the camera performance for semiconductor machine vision applications, especially targeting at low image contrast high speed applications. Current mainline cameras and high-end OEM cameras are evaluated with this model. Camera performances are clearly differentiated among CMOS technology generations and vendors, which will facilitate application driven camera selection and operation optimization. The new challenges for CMOS detectors are discussed for semiconductor inspection applications.

  19. Wavelength dependence of silicon avalanche photodiode fabricated by CMOS process

    NASA Astrophysics Data System (ADS)

    Mohammed Napiah, Zul Atfyi Fauzan; Hishiki, Takuya; Iiyama, Koichi

    2017-07-01

    Avalanche photodiodes fabricated by CMOS process (CMOS-APDs) have features of high avalanche gain below 10 V, wide bandwidth over 5 GHz, and easy integration with electronic circuits. In CMOS-APDs, guard ring structure is introduced for high-speed operation by canceling photo-generated carriers in the substrate at the sacrifice of the responsivity. We describe here wavelength dependence of the responsivity and the bandwidth of the CMOS-APDs with shorted and opened guard ring structure.

  20. Extracted ion current density in close-coupling multi-antenna type radio frequency driven ion source: CC-MATIS

    SciTech Connect

    Oka, Y. E-mail: oka@LHD.nifs.ac.jp; Shoji, T.

    2014-02-15

    Positive ions are extracted by using a small extractor from the Close-Coupling Multi-Antenna Type radio frequency driven Ion Source. Two types of RF antenna are used. The maximum extracted ion current density reaches 0.106 A/cm{sup 2}. The RF net power efficiency of the extracted ion current density under standard condition is 11.6 mA/cm{sup 2}/kW. The efficiency corresponds to the level of previous beam experiments on elementary designs of multi-antenna sources, and also to the efficiency level of a plasma driven by a filament in the same chamber. The multi-antenna type RF plasma source is promising for all metal high density ion sources in a large volume chamber.

  1. Extracted ion current density in close-coupling multi-antenna type radio frequency driven ion source: CC-MATIS.

    PubMed

    Oka, Y; Shoji, T

    2014-02-01

    Positive ions are extracted by using a small extractor from the Close-Coupling Multi-Antenna Type radio frequency driven Ion Source. Two types of RF antenna are used. The maximum extracted ion current density reaches 0.106 A/cm(2). The RF net power efficiency of the extracted ion current density under standard condition is 11.6 mA/cm(2)/kW. The efficiency corresponds to the level of previous beam experiments on elementary designs of multi-antenna sources, and also to the efficiency level of a plasma driven by a filament in the same chamber. The multi-antenna type RF plasma source is promising for all metal high density ion sources in a large volume chamber.

  2. Ion traps fabricated in a CMOS foundry

    SciTech Connect

    Mehta, K. K.; Ram, R. J.; Eltony, A. M.; Chuang, I. L.; Bruzewicz, C. D.; Sage, J. M. Chiaverini, J.

    2014-07-28

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  3. New integration concept of PIN photodiodes in 0.35μm CMOS technologies

    NASA Astrophysics Data System (ADS)

    Jonak-Auer, I.; Teva, J.; Park, J. M.; Jessenig, S.; Rohrbacher, M.; Wachmann, E.

    2012-06-01

    We report on a new and very cost effective way to integrate PIN photo detectors into a standard CMOS process. Starting with lowly p-doped (intrinsic) EPI we need just one additional mask and ion implantation in order to provide doping concentrations very similar to standard CMOS substrates to areas outside the photoactive regions. Thus full functionality of the standard CMOS logic can be guaranteed while the photo detectors highly benefit from the low doping concentrations of the intrinsic EPI. The major advantage of this integration concept is that complete modularity of the CMOS process remains untouched by the implementation of PIN photodiodes. Functionality of the implanted region as host of logic components was confirmed by electrical measurements of relevant standard transistor as well as ESD protection devices. We also succeeded in establishing an EPI deposition process in austriamicrosystems 200mm wafer fabrication which guarantees the formation of very lowly p-doped intrinsic layers, which major semiconductor vendors could not provide. With our EPI deposition process we acquire doping levels as low as 1•1012/cm3. In order to maintain those doping levels during CMOS processing we employed special surface protection techniques. After complete CMOS processing doping concentrations were about 4•1013/cm3 at the EPI surface while the bulk EPI kept its original low doping concentrations. Photodiode parameters could further be improved by bottom antireflective coatings and a special implant to reduce dark currents. For 100×100μm2 photodiodes in 20μm thick intrinsic EPI on highly p-doped substrates we achieved responsivities of 0.57A/W at λ=675nm, capacitances of 0.066pF and dark currents of 0.8pA at 2V reverse voltage.

  4. Design of Low Power CMOS Read-Out with TDI Function for Infrared Linear Photodiode Array Detectors

    NASA Technical Reports Server (NTRS)

    Vizcaino, Paul; Ramirez-Angulo, Jaime; Patel, Umesh D.

    2007-01-01

    A new low voltage CMOS infrared readout circuit using the buffer-direct injection method is presented. It uses a single supply voltage of 1.8 volts and a bias current of 1uA. The time-delay integration technique is used to increase the signal to noise ratio. A current memory circuit with faulty diode detection is used to remove dark current for background compensation and to disable a photodiode in a cell if detected as faulty. Simulations are shown that verify the circuit that is currently in fabrication in 0.5ym CMOS technology.

  5. High-temperature Complementary Metal Oxide Semiconductors (CMOS)

    NASA Technical Reports Server (NTRS)

    Mcbrayer, J. D.

    1981-01-01

    The results of an investigation into the possibility of using complementary metal oxide semiconductor (CMOS) technology for high temperature electronics are presented. A CMOS test chip was specifically developed as the test bed. This test chip incorporates CMOS transistors that have no gate protection diodes; these diodes are the major cause of leakage in commercial devices.

  6. Low power, CMOS digital autocorrelator spectrometer for spaceborne applications

    NASA Technical Reports Server (NTRS)

    Chandra, Kumar; Wilson, William J.

    1992-01-01

    A 128-channel digital autocorrelator spectrometer using four 32 channel low power CMOS correlator chips was built and tested. The CMOS correlator chip uses a 2-bit multiplication algorithm and a full-custom CMOS VLSI design to achieve low DC power consumption. The digital autocorrelator spectrometer has a 20 MHz band width, and the total DC power requirement is 6 Watts.

  7. Characterization of spectral optical responsivity of Si-photodiode junction combinations available in a 0.35μm HV-CMOS technology

    NASA Astrophysics Data System (ADS)

    Kraxner, A.; Wachmann, E.; Jonak-Auer, I.; Teva, J.; Park, J. M.; Minixhofer, R.

    2013-05-01

    The 0.35μm HV-CMOS process technology utilizes several junctions with different doping levels and depths. This process supports complete modular 3V and 5V standard CMOS functionality and offers a wide set of HV transistor types capable for operating voltages from 20V to 120V made available with only 2 more mask adders [1]. Compared to other reported integration of photo detection functionalities in normal CMOS processes [2] or special modified process technologies [3] a much wider variety of junction combinations is already intrinsically available in the investigated technology. Such junctions include beside the standard n+ and p+ source/drain dopings also several combinations of shallow and deep tubs for both p-wells and n-wells. The availability of junction from submicron to 7μm depths enables the selection of appropriate spectral sensitivity ranging from ultraviolet to infrared wavelengths. On the other side by appropriate layouts the contributions of photocurrents of shallower or deeper photo carrier generation can be kept to a minimum. We also show that by analytically modelling the space charge regions of the selected junctions the drift and diffusion carrier contributions can be calculated with a very good match indicating also the suppression of diffusion current contribution. We present examples of spectral responsivity of junction combinations optimized for peak sensitivity in the ranges of 380-450nm, 450-600nm or 700-900nm. By appropriate junction choice the ratios of the generated photo currents in their respective peak zones can exhibit more than a factor of 10 compared to the other photo diode combinations. This enables already without further filter implementation a very good spectral resolution for colour sensing applications. Finally the possible junction combinations are also assessed by the achievable dark current for optimized signal to noise characteristic.

  8. Current Research on Molasses as an Alternative Energy Source for Organic Dairy Herds

    USDA-ARS?s Scientific Manuscript database

    As organic grain prices have increased and organic milk prices have decreased, dairy farmers are seeking lower-cost supplementation strategies. Sugarcane molasses, a rich source of sucrose, seems to be a viable option as a source of energy. Molasses frequently costs less per pound of dry matter than...

  9. Management of agricultural nonpoint source pollution in China: current status and challenges.

    PubMed

    Wang, Xiaoyan

    2006-01-01

    Water quality in China shows an overall trend of deterioration in recent years. Nonpoint source pollution from agricultural and rural regions is the leading source of water pollution. The agricultural nonpoint source pollutants are mainly from fertilization of cropland, excessive livestock and poultry breeding and undefined disposal of daily living wastes in rural areas. Agricultural nonpoint sources contribute the main source of pollution to most watersheds in China, but they are ignored in management strategy and policy. Due to the lack of full understanding of water pollution control and management and the lack of perfect water quality standard systems and practical legislative regulations, agricultural nonpoint source pollution will become one of the biggest challenges to the sustainable development of rural areas and to society as a whole. The system for agricultural nonpoint source pollution control in China should include an appropriate legislation and policy framework, financing mechanisms, monitoring system, and technical guidelines and standards. The management of agricultural nonpoint source pollution requires multidisciplinary approaches that will involve a range of government departments, institutions and the public.

  10. Effect of high energy electrons on H- production and destruction in a high current DC negative ion source for cyclotron

    NASA Astrophysics Data System (ADS)

    Onai, M.; Etoh, H.; Aoki, Y.; Shibata, T.; Mattei, S.; Fujita, S.; Hatayama, A.; Lettry, J.

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H- production. The modelling results reasonably explains the dependence of the H- extraction current on the arc-discharge power in the experiments.

  11. Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.

    PubMed

    Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.

  12. End-of-fabrication CMOS process monitor

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Allen, R. A.; Blaes, B. R.; Hannaman, D. J.; Lieneweg, U.; Lin, Y.-S.; Sayah, H. R.

    1990-01-01

    A set of test 'modules' for verifying the quality of a complementary metal oxide semiconductor (CMOS) process at the end of the wafer fabrication is documented. By electrical testing of specific structures, over thirty parameters are collected characterizing interconnects, dielectrics, contacts, transistors, and inverters. Each test module contains a specification of its purpose, the layout of the test structure, the test procedures, the data reduction algorithms, and exemplary results obtained from 3-, 2-, or 1.6-micrometer CMOS/bulk processes. The document is intended to establish standard process qualification procedures for Application Specific Integrated Circuits (ASIC's).

  13. Real-time multi-DSP control of three-phase current-source unity power factor PWM rectifier

    SciTech Connect

    Xiao Wang; Boon-Teck Ooi . Dept. of Electrical Engineering)

    1993-07-01

    The design of a real-time multi-DSP controller for a high-quality six-valve three-phase current-source unity power factor PWM rectifier is discussed in this paper. With the decoupler preprocessor and the dynamic trilogic PWM trigger scheme, each of the three input currents can be controlled independently. Based on the a-b-c frame system model and the fast parallel computer control, the pole-placement control method is implemented successfully to achieve fast response in the ac currents. The low-frequency resonance in the ac filter L-C networks has been damped effectively. The experimental results are obtained from a 1-kVA bipolar transistor current-source PWM rectifier with a real-time controller using three TMS320C25 DSP's.

  14. Subthreshold Current and Swing Modeling of Gate Underlap DG MOSFETs with a Source/Drain Lateral Gaussian Doping Profile

    NASA Astrophysics Data System (ADS)

    Singh, Kunal; Kumar, Sanjay; Goel, Ekta; Singh, Balraj; Kumar, Mirgender; Dubey, Sarvesh; Jit, Satyabrata

    2017-01-01

    This paper proposes a new model for the subthreshold current and swing of the short-channel symmetric underlap ultrathin double gate metal oxide field effect transistors with a source/drain lateral Gaussian doping profile. The channel potential model already reported earlier has been utilized to formulate the closed form expression for the subthreshold current and swing of the device. The effects of the lateral straggle and geometrical parameters such as the channel length, channel thickness, and oxide thickness on the off current and subthreshold slope have been demonstrated. The devices with source/drain lateral Gaussian doping profiles in the underlap structure are observed to be highly resistant to short channel effects while improving the current drive. The proposed model is validated by comparing the results with the numerical simulation data obtained by using the commercially available ATLAS™, a two-dimensional (2-D) device simulator from SILVACO.

  15. High Current, High Density Arc Plasma as a New Source for WiPAL

    NASA Astrophysics Data System (ADS)

    Waleffe, Roger; Endrizzi, Doug; Myers, Rachel; Wallace, John; Clark, Mike; Forest, Cary; WiPAL Team

    2016-10-01

    The Wisconsin Plasma Astrophysics Lab (WiPAL) has installed a new array of nineteen plasma sources (plasma guns) on its 3 m diameter, spherical vacuum vessel. Each gun is a cylindrical, molybdenum, washer-stabilized, arc plasma source. During discharge, the guns are maintained at 1.2 kA across 100 V for 10 ms by the gun power supply establishing a high density plasma. Each plasma source is fired independently allowing for adjustable plasma parameters, with densities varying between 1018 -1019 m-3 and electron temperatures of 5-15 eV. Measurements were characterized using a 16 tip Langmuir probe. The plasma source will be used as a background plasma for the magnetized coaxial plasma gun (MCPG), the Terrestrial Reconnection Experiment (TREX), and as the plasma source for a magnetic mirror experiment. Temperature, density, and confinement results will be presented. This work is supported by the DoE and the NSF.

  16. Physical and technological limitations of NanoCMOS devices to the end of the roadmap and beyond

    NASA Astrophysics Data System (ADS)

    Deleonibus, S.

    2006-12-01

    Since the end of the last millenium, the microelectronics industry has been facing new issues as far as CMOS devices scaling is concerned. Linear scaling will be possible in the future if new materials are introduced in CMOS device structures or if new device architectures are implemented. Innovations in the electronics history have been possible because of the strong association between devices and materials research. The demand for low voltage, low power and high performance are the great challenges for the engineering of sub 50nm gate length CMOS devices. Functional CMOS devices in the range of 5nm channel length have been demonstrated. The alternative architectures allowing to increase devices drivability and reduce power consumption are reviewed. The issues in the field of gate stack, channel, substrate, as well as source and drain engineering are addressed. HiK gate dielectric and metal gate are among the most strategic options to consider for power consumption and low supply voltage management. By introducing new materials (Ge, diamond/graphite carbon, HiK, ...), Si based CMOS will be scaled beyond the ITRS as the future System-on-Chip Platform integrating also new disruptive devices. For example, the association of C-diamond with HiK, as a combination for new functionalized Buried Insulators, will bring new ways of improving short channel effects and suppress self-heating. Because of the low parasitics required to obtain high performance circuits, alternative devices will hardly compete against logic CMOS.

  17. The dependence of extracted current on discharge gas pressure in neutral beam ion sources on HL-2A tokamak

    SciTech Connect

    Wei, H. L.; Cao, J. Y.; Rao, J.; Lei, G. J.; Jiang, S. F.; Liu, H.; Yu, L. M.; Xie, W. M.; Li, M.; Yang, X. F.; Zou, G. Q.; Lu, D. L.; Duan, X. R.

    2012-02-15

    The discharge gas pressure is a key factor to influence the extracted current of ion source. In this paper, the dependence of extracted current on discharge gas pressure was investigated in detail at different arc discharge currents. The discharge gas pressure with a very broad range (0.1 Pa-2.7 Pa) was scanned for the first time. It is turned out that, with the increasing of discharge gas pressure, the extracted current increases and the arc voltage decreases at different arc currents; however, when the discharge gas pressure exceeds a certain value, the extracted current decreases. For the same discharge gas pressure, the higher the arc current, the higher the arc voltage and the extracted current are. The arc efficiency was also calculated, and its dependence on gas pressure was almost the same with the dependence of extracted current on gas pressure, but at the same discharge gas pressure, the lower the arc current, the higher the arc efficiency is and the lower the extracted current is.

  18. Comment on "Effects of Magnetic Field Gradient on Ion Beam Current in Cylindrical Hall Ion Source

    SciTech Connect

    Raitses, Y.; Smirnov A.; Fisch, N.J.

    2008-08-29

    It is argued that the key difference of the cylindrical Hall thruster (CHT) as compared to the end-Hall ion source cannot be exclusively attributed to the magnetic field topology [Tang et al. J. Appl. Phys., 102, 123305 (2007)]. With a similar mirror-type topology, the CHT configuration provides the electric field with nearly equipotential magnetic field surfaces and a better suppression of the electron cross-field transport, as compared to both the end-Hall ion source and the cylindrical Hall ion source of Tang et al.

  19. Hot-carrier-reliability design rules for translating device degradation to CMOS digital circuit degradation

    NASA Astrophysics Data System (ADS)

    Quader, Khandker N.; Fang, Peng; Yue, John T.; Ko, Ping K.; Hu, Chenming

    1994-05-01

    Long term ring-oscillator hot-carrier degradation data and simulation results are compared to demonstrate that a circuit reliability simulator BERT can predict CMOS digital circuit speed degradation from transistor DC stress data. Initial fast degradation is noted and attributed to the 'zero crossing' effect caused by PMOSFET current enhancement. Saturation drain current, measured at V(sub gs) = V(sub ds) = Vdd/2, is a better monitor for CMOS circuit hot-carrier reliability. We present generalized hot-carrier-reliability design rules, lifetime and speed factors, that translate DC device lifetime to CMOS digital circuit lifetime. The design rules can roughly predict CMOS circuit degradation during the initial design and can aid reliability engineers to quickly estimate the overall product hot-carrier reliability. The NMOSFET and PMOSFET lifetime factors are found to obey 4/ft(sub rise) and 10/ft(sub fall), respectively. Typically, the NMOSFET and PMOSFET speed degradation factors are 1/4 and 1/2, respectively, with saturation region drain current as the monitor while, for a 100 MHz operating frequency and for an input rise time of 0.35 ns, the NMOSFET and PMOSFET lifetime factors are 120 and 300, respectively.

  20. Ion current detector for high pressure ion sources for monitoring separations

    DOEpatents

    Smith, Richard D.; Wahl, Jon H.; Hofstadler, Steven A.

    1996-01-01

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source.

  1. Ion current detector for high pressure ion sources for monitoring separations

    DOEpatents

    Smith, R.D.; Wahl, J.H.; Hofstadler, S.A.

    1996-08-13

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source. 7 figs.

  2. Gas field ion source current stability for trimer and single atom terminated W(111) tips

    SciTech Connect

    Urban, Radovan; Wolkow, Robert A.; Pitters, Jason L.

    2012-06-25

    Tungsten W(111) oriented trimer-terminated tips as well as single atom tips, fabricated by a gas and field assisted etching and evaporation process, were investigated with a view to scanning ion microscopy and ion beam writing applications. In particular, ion current stability was studied for helium and neon imaging gases. Large ion current fluctuations from individual atomic sites were observed when a trimer-terminated tip was used for the creation of neon ion beam. However, neon ion current was stable when a single atom tip was employed. No such current oscillations were observed for either a trimer or a single atom tip when imaged with helium.

  3. A cookbook for building a high-current dimpled H magnetron source for accelerators

    SciTech Connect

    Bollinger, Daniel S.; Karns, Patrick R.; Tan, Cheng -Yang

    2015-10-30

    A high-current (>50 mA) dimpled H magnetron source has been built at Fermilab for supplying H beam to the entire accelerator complex. Despite many decades of expertise with slit H magnetron sources at Fermilab, we were faced with many challenges from the dimpled H magnetron source, which needed to be overcome in order to make it operational. Dimpled H sources for high-energy physics are not new: Brookhaven National Laboratory has operated a dimpled H- source for more than two decades. However, the transference of that experience to Fermilab took about two years because a cookbook for building this type of source did not exist and seemingly innocuous or undocumented choices had a huge impact on the success or failure for this type of source. Moreover, it is the goal of this paper to document the reasons for these choices and to present a cookbook for building and operating dimpled H magnetron sources.

  4. Characterization and Performance of a High-Current-Density Ion Implanter with Magnetized Hollow-Cathode Plasma Source

    NASA Astrophysics Data System (ADS)

    Falkenstein, Zoran; Rej, Donald; Gavrilov, Nikolai

    1998-10-01

    In a collaboration between the Institute of Electrophysics (IEP) and the Los Alamos National Laboratory (LANL), the IEP has developed an industrial scalable, high-power, large-area ion source for the surface modification of materials. The plasma source of the ion beam source can be described as a pulsed glow discharge with a cold, hollow-cathode in a weak magnetic field. Extraction and focusing of positive ions by an acceleration and ion-optical plate system renders the generation of a homogeneous, large-area ion beam with an averaged total ion current of up to 50 mA at acceleration voltages of up to 50 kV. The principle set-up of the ion beam source as well as some electrical characteristics (gas discharge current and the extracted ion beam current) are presented for a lab-scale prototype. Measurements of the radial ion current density profiles within the ion beam for various discharge parameters, as well as results on surface modification by ion implantation of nitrogen into aluminum and chromium are presented. Finally, a comparison of the applied ion dose with the retained ion doses is given.

  5. [Analytical method for the potential distribution of head sphere model under the stimulation of point current source].

    PubMed

    Xu, Zheng; He, Wei; He, Chuanhong; Zhang, Zhanlong

    2008-08-01

    The 4-layer sphere model of human head was built; the layers from outside to inside represented the scalp, the skull, the CFS and the brain, respectively. The point current source placed on the outmost layer was regarded as the boundary condition, and the method of separation of variables was used to solve the equations. The potential distribution and the current expression were given, and the isopotential-line map and current lines were drawn. The simulation result can be used to analyze head EIT problems.

  6. Integration of solid-state nanopores in a 0.5 μm CMOS foundry process.

    PubMed

    Uddin, A; Yemenicioglu, S; Chen, C-H; Corigliano, E; Milaninia, K; Theogarajan, L

    2013-04-19

    High-bandwidth and low-noise nanopore sensor and detection electronics are crucial in achieving single-DNA-base resolution. A potential way to accomplish this goal is to integrate solid-state nanopores within a CMOS platform, in close proximity to the biasing electrodes and custom-designed amplifier electronics. Here we report the integration of solid-state nanopore devices in a commercial complementary metal-oxide-semiconductor (CMOS) potentiostat chip implemented in On-Semiconductor's 0.5 μm technology. Nanopore membranes incorporating electrodes are fabricated by post-CMOS micromachining utilizing the n+ polysilicon/SiO2/n+ polysilicon capacitor structure available in the aforementioned process. Nanopores are created in the CMOS process by drilling in a transmission electron microscope and shrinking by atomic layer deposition. We also describe a batch fabrication method to process a large of number of electrode-embedded nanopores with sub-10 nm diameter across CMOS-compatible wafers by electron beam lithography and atomic layer deposition. The CMOS-compatibility of our fabrication process is verified by testing the electrical functionality of on-chip circuitry. We observe high current leakage with the CMOS nanopore devices due to the ionic diffusion through the SiO2 membrane. To prevent this leakage, we coat the membrane with Al2O3, which acts as an efficient diffusion barrier against alkali ions. The resulting nanopore devices also exhibit higher robustness and lower 1/f noise as compared to SiO2 and SiNx. Furthermore, we propose a theoretical model for our low-capacitance CMOS nanopore devices, showing good agreement with the experimental value. In addition, experiments and theoretical models of translocation studies are presented using 48.5 kbp λ-DNA in order to prove the functionality of on-chip pores coated with Al2O3.

  7. Integration of solid-state nanopores in a 0.5 μm cmos foundry process

    PubMed Central

    Uddin, A; Yemenicioglu, S; Chen, C-H; Corigliano, E; Milaninia, K; Theogarajan, L

    2013-01-01

    High-bandwidth and low-noise nanopore sensor and detection electronics are crucial in achieving single-DNA base resolution. A potential way to accomplish this goal is to integrate solid-state nanopores within a CMOS platform, in close proximity to the biasing electrodes and custom-designed amplifier electronics. Here we report the integration of solid-state nanopore devices in a commercial complementary metal-oxide semiconductor (CMOS) potentiostat chip implemented in On-Semiconductor’s 0.5 μm technology. Nanopore membranes incorporating electrodes are fabricated by post-CMOS micromachining utilizing the N+ polysilicon/SiO2/N+ polysilicon capacitor structure available in the aforementioned process. Nanopores are created in the CMOS process by drilling in a transmission electron microscope and shrinking by atomic layer deposition. We also describe a batch fabrication method to process a large of number of electrode-embedded nanopores with sub-10 nm diameter across CMOS-compatible wafers by electron beam lithography and atomic layer deposition. The CMOS-compatibility of our fabrication process is verified by testing the electrical functionality of on-chip circuitry. We observe high current leakage with the CMOS nanopore devices due to the ionic diffusion through the SiO2 membrane. To prevent this leakage, we coat the membrane with Al2O3 which acts as an efficient diffusion barrier against alkali ions. The resulting nanopore devices also exhibit higher robustness and lower 1/f noise as compared to SiO2 and SiNx. Furthermore, we propose a theoretical model for our low-capacitance CMOS nanopore devices, showing good agreement with the experimental value. In addition, experiments and theoretical models of translocation studies are presented using 48.5 kbp λ-DNA in order to prove the functionality of on-chip pores coated with Al2O3. PMID:23519330

  8. The effect of the random distribution of electronic components in the output characteristics of the Howland current source

    NASA Astrophysics Data System (ADS)

    Bertemes-Filho, P.; Felipe, A.

    2013-04-01

    When a Howland source is designed, the components are chosen so that the designed source has the desired characteristics. However, the operational amplifier limitations and resistor tolerances causes undesired behaviours. This work proposes to take in account the influence of the random distribution of the commercial resistors in the Howland circuit over the frequency range of 10 Hz to 10 MHz. The probability density function due to small changes over the resistors was calculated by using an analytical model. Results show that both output current and impedance are very sensitive to the resistor tolerances. It is shown that the output impedance is very dependent on the open-loop gain of the Opamp rather than the resistor tolerances, especially at higher frequencies. This might improve the implementations of real current source used in electrical bioimpedance.

  9. Macromolecular crystallography with a large format CMOS detector

    SciTech Connect

    Nix, Jay C.

    2016-07-27

    Recent advances in CMOS technology have allowed the production of large surface area detectors suitable for macromolecular crystallography experiments [1]. The Molecular Biology Consortium (MBC) Beamline 4.2.2 at the Advanced Light Source in Berkeley, CA, has installed a 2952 x 2820 mm RDI CMOS-8M detector with funds from NIH grant S10OD012073. The detector has a 20nsec dead pixel time and performs well with shutterless data collection strategies. The sensor obtains sharp point response and minimal optical distortion by use of a thin fiber-optic plate between the phosphor and sensor module. Shutterless data collections produce high-quality redundant datasets that can be obtained in minutes. The fine-sliced data are suitable for processing in standard crystallographic software packages (XDS, HKL2000, D*TREK, MOSFLM). Faster collection times relative to the previous CCD detector have resulted in a record number of datasets collected in a calendar year and de novo phasing experiments have resulted in publications in both Science and Nature [2,3]. The faster collections are due to a combination of the decreased overhead requirements of shutterless collections combined with exposure times that have decreased by over a factor of 2 for images with comparable signal to noise of the NOIR-1 detector. The overall increased productivity has allowed the development of new beamline capabilities and data collection strategies.

  10. Si light-emitting device in integrated photonic CMOS ICs

    NASA Astrophysics Data System (ADS)

    Xu, Kaikai; Snyman, Lukas W.; Aharoni, Herzl

    2017-07-01

    The motivation for integrated Si optoelectronics is the creation of low-cost photonics for mass-market applications. Especially, the growing demand for sensitive biochemical sensors in the environmental control or medicine leads to the development of integrated high resolution sensors. Here CMOS-compatible Si light-emitting device structures are presented for investigating the effect of various depletion layer profiles and defect engineering on the photonic transition in the 1.4-2.8 eV. A novel Si device is proposed to realize both a two-terminal Si-diode light-emitting device and a three-terminal Si gate-controlled diode light-emitting device in the same device structure. In addition to the spectral analysis, differences between two-terminal and three-terminal devices are discussed, showing the light emission efficiency change. The proposed Si optical source may find potential applications in micro-photonic systems and micro-optoelectro-mechanical systems (MOEMS) in CMOS integrated circuitry.

  11. Review of radiation damage studies on DNW CMOS MAPS

    NASA Astrophysics Data System (ADS)

    Traversi, G.; Gaioni, L.; Manazza, A.; Manghisoni, M.; Ratti, L.; Re, V.; Zucca, S.; Bettarini, S.; Rizzo, G.; Morsani, F.; Bosisio, L.; Rashevskaya, I.; Cindro, V.

    2013-12-01

    Monolithic active pixel sensors fabricated in a bulk CMOS technology with no epitaxial layer and standard resistivity (10 Ω cm) substrate, featuring a deep N-well as the collecting electrode (DNW MAPS), have been exposed to γ-rays, up to a final dose of 10 Mrad (SiO2), and to neutrons from a nuclear reactor, up to a total 1 MeV neutron equivalent fluence of about 3.7 ·1013cm-2. The irradiation campaign was aimed at studying the effects of radiation on the most significant parameters of the front-end electronics and on the charge collection properties of the sensors. Device characterization has been carried out before and after irradiations. The DNW MAPS irradiated with 60Co γ-rays were also subjected to high temperature annealing (100 °C for 168 h). Measurements have been performed through a number of different techniques, including electrical characterization of the front-end electronics and of DNW diodes, laser stimulation of the sensors and tests with 55Fe and 90Sr radioactive sources. This paper reviews the measurement results, their relation with the damage mechanisms underlying performance degradation and provides a new comparison between DNW devices and MAPS fabricated in a CMOS process with high resistivity (1 kΩ cm) epitaxial layer.

  12. HV-CMOS detectors in BCD8 technology

    NASA Astrophysics Data System (ADS)

    Andreazza, A.; Castoldi, A.; Ceriale, V.; Chiodini, G.; Citterio, M.; Darbo, G.; Gariano, G.; Gaudiello, A.; Guazzoni, C.; Joshi, A.; Liberali, V.; Passadore, S.; Ragusa, F.; Ruscino, E.; Sbarra, C.; Shrimali, H.; Sidoti, A.; Stabile, A.; Yadav, I.; Zaffaroni, E.

    2016-11-01

    This paper presents the first pixel detector realized using the BCD8 technology of STMicroelectronics. The BCD8 is a 160 nm process with bipolar, CMOS and DMOS devices; mainly targeted for an automotive application. The silicon particle detector is realized as a pixel sensor diode with a dimension of 250 × 50 μm2. To support the signal sensitivity of pixel diode, the circuit simulations have been performed with a substrate voltage of 50 V. The analog signal processing circuitry and the digital operation of the circuit is designed with the supply voltage of 1.8 V. Moreover, an analog processing part of the pixel detector circuit is confined in a unit pixel (diode sensor) to achieve 100 % fill factor. As a first phase of the design, an array of 8 pixels and 4 passive diodes have been designed and measured experimentally. The entire analog circuitry including passive diodes is implemented in a single chip. This chip has been tested experimentally with 70 V voltage capability, to evaluate its suitability. The sensor on a 125 Ωcm resistivity substrate has been characterized in the laboratory. The CMOS sensor realizes a depleted region of several tens of micrometer. The characterization shows a uniform breakdown at 70 V before irradiation and an approximate capacitance of 80 fF at 50 V of reverse bias voltage. The response to ionizing radiation is tested using radioactive sources and an X-ray tube.

  13. CMOS and sCMOS imaging performance comparison by digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Flores-Moreno, Jorge Mauricio; De la Torre Ibarra, Manuel H.; del Socorro Hernández-Montes, María; Perez Lopez, Carlos; Santoyo, Fernando Mendoza

    2016-12-01

    We use a digital holographic interferometric setup to assess, as a proof of concept, two state-of-the-art sensors (CMOS and sCMOS cameras) that are widely used in nondestructive testing (NDT). This interferometric study is intended to evaluate the image quality recorded by any camera used in NDT. The assessing relies on the quantification of the optical phase information recovered by the cameras used for this study. For this, we calculate the signal-to-noise ratio, correlation coefficient, and quality index (Q-index) as main figures-of-merit. As far as we know, the Q-index has not been used for evaluation of the optical phase coming from image holograms. The CMOS and sCMOS sensors used record the same deformation event under the same experimental conditions. The experiment involves the inspection of a large sample (>1 m2 of area) which implies low illumination conditions for the imaging sensors. The retrieved CMOS optical phase shows artifacts that are not observed in the sCMOS. An analysis of these two groups of interferometric images is presented and discussed. The methodology set forth here can be applied to evaluate other sensors such as CCDs and EM-CCDs.

  14. On the integration of ultrananocrystalline diamond (UNCD) with CMOS chip

    DOE PAGES

    Mi, Hongyi; Yuan, Hao -Chih; Seo, Jung -Hun; ...

    2017-03-27

    A low temperature deposition of high quality ultrananocrystalline diamond (UNCD) film onto a finished Si-based CMOS chip was performed to investigate the compatibility of the UNCD deposition process with CMOS devices for monolithic integration of MEMS on Si CMOS platform. DC and radio-frequency performances of the individual PMOS and NMOS devices on the CMOS chip before and after the UNCD deposition were characterized. Electrical characteristics of CMOS after deposition of the UNCD film remained within the acceptable ranges, namely showing small variations in threshold voltage Vth, transconductance gm, cut-off frequency fT and maximum oscillation frequency fmax. Finally, the results suggestmore » that low temperature UNCD deposition is compatible with CMOS to realize monolithically integrated CMOS-driven MEMS/NEMS based on UNCD.« less

  15. Design and realization of CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Xiao, Zexin

    2008-02-01

    A project was presented that instrumental design of an economical CMOS microscope image sensor. A high performance, low price, black-white camera chip OV5116P was used as the core of the sensor circuit; Designing and realizing peripheral control circuit of sensor; Through the control on dial switch to realize different functions of the sensor chip in the system. For example: auto brightness level descending function on or off; gamma correction function on or off; auto and manual backlight compensation mode conversion and so on. The optical interface of sensor is designed for commercialization and standardization. The images of sample were respectively gathered with CCD and CMOS. Result of the experiment indicates that both performances were identical in several aspects as follows: image definition, contrast control, heating degree and the function can be adjusted according to the demand of user etc. The imperfection was that the CMOS with smaller field and higher noise than CCD; nevertheless, the maximal advantage of choosing the CMOS chip is its low cost. And its imaging quality conformed to requirement of the economical microscope image sensor.

  16. A Hybrid CMOS-Memristor Neuromorphic Synapse.

    PubMed

    Azghadi, Mostafa Rahimi; Linares-Barranco, Bernabe; Abbott, Derek; Leong, Philip H W

    2017-04-01

    Although data processing technology continues to advance at an astonishing rate, computers with brain-like processing capabilities still elude us. It is envisioned that such computers may be achieved by the fusion of neuroscience and nano-electronics to realize a brain-inspired platform. This paper proposes a high-performance nano-scale Complementary Metal Oxide Semiconductor (CMOS)-memristive circuit, which mimics a number of essential learning properties of biological synapses. The proposed synaptic circuit that is composed of memristors and CMOS transistors, alters its memristance in response to timing differences among its pre- and post-synaptic action potentials, giving rise to a family of Spike Timing Dependent Plasticity (STDP). The presented design advances preceding memristive synapse designs with regards to the ability to replicate essential behaviours characterised in a number of electrophysiological experiments performed in the animal brain, which involve higher order spike interactions. Furthermore, the proposed hybrid device CMOS area is estimated as [Formula: see text] in a [Formula: see text] process-this represents a factor of ten reduction in area with respect to prior CMOS art. The new design is integrated with silicon neurons in a crossbar array structure amenable to large-scale neuromorphic architectures and may pave the way for future neuromorphic systems with spike timing-dependent learning features. These systems are emerging for deployment in various applications ranging from basic neuroscience research, to pattern recognition, to Brain-Machine-Interfaces.

  17. Fully CMOS-compatible titanium nitride nanoantennas

    SciTech Connect

    Briggs, Justin A.; Naik, Gururaj V.; Baum, Brian K.; Dionne, Jennifer A.; Petach, Trevor A.; Goldhaber-Gordon, David

    2016-02-01

    CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements on plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing.

  18. Low power SEU immune CMOS memory circuits

    NASA Technical Reports Server (NTRS)

    Liu, M. N.; Whitaker, Sterling

    1992-01-01

    The authors report a design improvement for CMOS static memory circuits hardened against single event upset (SEU) using a recently proposed logic/circuit design technique. This improvement drastically reduces static power consumption, reduces the number of transistors required in a D flip-flop design, and eliminates the possibility of capturing an upset state in the slave section during a clock transition.

  19. SEU hardening of CMOS memory circuit

    NASA Technical Reports Server (NTRS)

    Whitaker, S.; Canaris, J.; Liu, K.

    1990-01-01

    This paper reports a design technique to harden CMOS memory circuits against Single Event Upset (SEU) in the space environment. A RAM cell and Flip Flop design are presented to demonstrate the method. The Flip Flop was used in the control circuitry for a Reed Solomon encoder designed for the Space Station.

  20. Improving CMOS-compatible Germanium photodetectors.

    PubMed

    Li, Guoliang; Luo, Ying; Zheng, Xuezhe; Masini, Gianlorenzo; Mekis, Attila; Sahni, Subal; Thacker, Hiren; Yao, Jin; Shubin, Ivan; Raj, Kannan; Cunningham, John E; Krishnamoorthy, Ashok V

    2012-11-19

    We report design improvements for evanescently coupled Germanium photodetectors grown at low temperature. The resulting photodetectors with 10 μm Ge length manufactured in a commercial CMOS process achieve >0.8 A/W responsivity over the entire C-band, with a device capacitance of <7 fF based on measured data.

  1. A fail-safe CMOS logic gate

    NASA Technical Reports Server (NTRS)

    Bobin, V.; Whitaker, S.

    1990-01-01

    This paper reports a design technique to make Complex CMOS Gates fail-safe for a class of faults. Two classes of faults are defined. The fail-safe design presented has limited fault-tolerance capability. Multiple faults are also covered.

  2. Radiation Tolerance of 65nm CMOS Transistors

    DOE PAGES

    Krohn, M.; Bentele, B.; Christian, D. C.; ...

    2015-12-11

    We report on the effects of ionizing radiation on 65 nm CMOS transistors held at approximately -20°C during irradiation. The pattern of damage observed after a total dose of 1 Grad is similar to damage reported in room temperature exposures, but we observe less damage than was observed at room temperature.

  3. CMOS preamplifiers for detectors large and small

    SciTech Connect

    O`Connor, P.

    1997-12-31

    We describe four CMOS preamplifiers developed for multiwire proportional chambers (MWPC) and silicon drift detectors (SDD) covering a capacitance range from 150 pF to 0.15 pF. Circuit techniques to optimize noise performance, particularly in the low-capacitance regime, are discussed.

  4. Modeling of single event transients with dual double-exponential current sources: Implications for logic cell characterization

    DOE PAGES

    Black, Dolores Archuleta; Robinson, William H.; Wilcox, Ian Zachary; ...

    2015-08-07

    Single event effects (SEE) are a reliability concern for modern microelectronics. Bit corruptions can be caused by single event upsets (SEUs) in the storage cells or by sampling single event transients (SETs) from a logic path. Likewise, an accurate prediction of soft error susceptibility from SETs requires good models to convert collected charge into compact descriptions of the current injection process. This paper describes a simple, yet effective, method to model the current waveform resulting from a charge collection event for SET circuit simulations. The model uses two double-exponential current sources in parallel, and the results illustrate why a conventionalmore » model based on one double-exponential source can be incomplete. Furthermore, a small set of logic cells with varying input conditions, drive strength, and output loading are simulated to extract the parameters for the dual double-exponential current sources. As a result, the parameters are based upon both the node capacitance and the restoring current (i.e., drive strength) of the logic cell.« less

  5. Modeling of single event transients with dual double-exponential current sources: Implications for logic cell characterization

    SciTech Connect

    Black, Dolores Archuleta; Robinson, William H.; Wilcox, Ian Zachary; Limbrick, Daniel B.; Black, Jeffrey D.

    2015-08-07

    Single event effects (SEE) are a reliability concern for modern microelectronics. Bit corruptions can be caused by single event upsets (SEUs) in the storage cells or by sampling single event transients (SETs) from a logic path. Likewise, an accurate prediction of soft error susceptibility from SETs requires good models to convert collected charge into compact descriptions of the current injection process. This paper describes a simple, yet effective, method to model the current waveform resulting from a charge collection event for SET circuit simulations. The model uses two double-exponential current sources in parallel, and the results illustrate why a conventional model based on one double-exponential source can be incomplete. Furthermore, a small set of logic cells with varying input conditions, drive strength, and output loading are simulated to extract the parameters for the dual double-exponential current sources. As a result, the parameters are based upon both the node capacitance and the restoring current (i.e., drive strength) of the logic cell.

  6. A comparison of two-dimensional techniques for converting magnetocardiogram maps into effective current source distributions

    NASA Astrophysics Data System (ADS)

    Ogata, K.; Kandori, A.; Miyashita, T.; Sekihara, K.; Tsukada, K.

    2011-01-01

    The aim of this study was to develop a method for converting the pseudo two-dimensional current given by a current-arrow map (CAM) into the physical current. The physical current distribution is obtained by the optimal solution in a least mean square sense with Tikhonov regularization (LMSTR). In the current dipole simulation, the current pattern differences (ΔJ) between the results of the CAM and the LMSTR with several regularization parameters (α = 10-1-10-15) are calculated. In magnetocardiographic (MCG) analysis, the depth (zd) of a reconstruction plane is chosen by using the coordinates of the sinus node, which is estimated from MCG signals at the early p-wave. The ΔJs at p-wave peaks, QRS-complex peaks, and T-wave peaks of MCG signals for healthy subjects are calculated. Furthermore, correlation coefficients and regression lines are also calculated from the current values of the CAM and the LMSTR during p-waves, QRS-complex, and T-waves of MCG signals. In the simulation, the ΔJs (α ≈ 10-10) had a minimal value. The ΔJs (α = 10-10) at p-wave peaks, QRS-complex peaks, and T-wave peaks of MCG signals for healthy subjects also had minimal value. The correlation coefficients of the current values given by the CAM and the LMSTR (α = 10-10) were greater than 0.9. Furthermore, slopes (y) of the regression lines are correlated with the depth (zd) (r = -0.93). Consequently, the CAM value can be transformed into the LMSTR current value by multiplying it by the slope (y) obtained from the depth (zd). In conclusion, the result given by the CAM can be converted into an effective physical current distribution by using the depth (zd).

  7. Low-Power SOI CMOS Transceiver

    NASA Technical Reports Server (NTRS)

    Fujikawa, Gene (Technical Monitor); Cheruiyot, K.; Cothern, J.; Huang, D.; Singh, S.; Zencir, E.; Dogan, N.

    2003-01-01

    The work aims at developing a low-power Silicon on Insulator Complementary Metal Oxide Semiconductor (SOI CMOS) Transceiver for deep-space communications. RF Receiver must accomplish the following tasks: (a) Select the desired radio channel and reject other radio signals, (b) Amplify the desired radio signal and translate them back to baseband, and (c) Detect and decode the information with Low BER. In order to minimize cost and achieve high level of integration, receiver architecture should use least number of external filters and passive components. It should also consume least amount of power to minimize battery cost, size, and weight. One of the most stringent requirements for deep-space communication is the low-power operation. Our study identified that two candidate architectures listed in the following meet these requirements: (1) Low-IF receiver, (2) Sub-sampling receiver. The low-IF receiver uses minimum number of external components. Compared to Zero-IF (Direct conversion) architecture, it has less severe offset and flicker noise problems. The Sub-sampling receiver amplifies the RF signal and samples it using track-and-hold Subsampling mixer. These architectures provide low-power solution for the short- range communications missions on Mars. Accomplishments to date include: (1) System-level design and simulation of a Double-Differential PSK receiver, (2) Implementation of Honeywell SOI CMOS process design kit (PDK) in Cadence design tools, (3) Design of test circuits to investigate relationships between layout techniques, geometry, and low-frequency noise in SOI CMOS, (4) Model development and verification of on-chip spiral inductors in SOI CMOS process, (5) Design/implementation of low-power low-noise amplifier (LNA) and mixer for low-IF receiver, and (6) Design/implementation of high-gain LNA for sub-sampling receiver. Our initial results show that substantial improvement in power consumption is achieved using SOI CMOS as compared to standard CMOS

  8. Review on high current 2.45 GHz electron cyclotron resonance sources (invited)

    SciTech Connect

    Gammino, S.; Celona, L.; Ciavola, G.; Maimone, F.; Mascali, D.

    2010-02-15

    The suitable source for the production of intense beams for high power accelerators must obey to the request of high brightness, stability, and reliability. The 2.45 GHz off-resonance microwave discharge sources are the ideal device to generate the requested beams, as they produce multimilliampere beams of protons, deuterons, and monocharged ions, remaining stable for several weeks without maintenance. A description of different technical designs will be given, analyzing their strength, and weakness, with regard to the extraction system and low energy beam transport line, as the presence of beam halo is detrimental for the accelerator.

  9. The design and characteristics of direct current glow discharge atomic emission source operated with plain and hollow cathodes.

    PubMed

    Qayyum, A; Mahmood, M I

    2008-01-07

    A compact direct current glow discharge atomic emission source has been designed and constructed for analytical applications. This atomic emission source works very efficiently at a low-input electrical power. The design has some features that make it distinct from that of the conventional Grimm glow discharge source. The peculiar cathode design offered greater flexibility on size and shape of the sample. As a result the source can be easily adopted to operate in Plain or Hollow Cathode configuration. I-V and spectroscopic characteristics of the source were compared while operating it with plain and hollow copper cathodes. It was observed that with hollow cathode, the source can be operated at a less input power and generates greater Cu I and Cu II line intensities. Also, the intensity of Cu II line rise faster than Cu I line with argon pressure for both cathodes. But the influence of pressure on Cu II lines was more significant when the source is operated with hollow cathode.

  10. Overview of CMOS process and design options for image sensor dedicated to space applications

    NASA Astrophysics Data System (ADS)

    Martin-Gonthier, P.; Magnan, P.; Corbiere, F.

    2005-10-01

    With the growth of huge volume markets (mobile phones, digital cameras...) CMOS technologies for image sensor improve significantly. New process flows appear in order to optimize some parameters such as quantum efficiency, dark current, and conversion gain. Space applications can of course benefit from these improvements. To illustrate this evolution, this paper reports results from three technologies that have been evaluated with test vehicles composed of several sub arrays designed with some space applications as target. These three technologies are CMOS standard, improved and sensor optimized process in 0.35μm generation. Measurements are focussed on quantum efficiency, dark current, conversion gain and noise. Other measurements such as Modulation Transfer Function (MTF) and crosstalk are depicted in [1]. A comparison between results has been done and three categories of CMOS process for image sensors have been listed. Radiation tolerance has been also studied for the CMOS improved process in the way of hardening the imager by design. Results at 4, 15, 25 and 50 krad prove a good ionizing dose radiation tolerance applying specific techniques.

  11. Noise Reduction Techniques and Scaling Effects towards Photon Counting CMOS Image Sensors

    PubMed Central

    Boukhayma, Assim; Peizerat, Arnaud; Enz, Christian

    2016-01-01

    This paper presents an overview of the read noise in CMOS image sensors (CISs) based on four-transistors (4T) pixels, column-level amplification and correlated multiple sampling. Starting from the input-referred noise analytical formula, process level optimizations, device choices and circuit techniques at the pixel and column level of the readout chain are derived and discussed. The noise reduction techniques that can be implemented at the column and pixel level are verified by transient noise simulations, measurement and results from recently-published low noise CIS. We show how recently-reported process refinement, leading to the reduction of the sense node capacitance, can be combined with an optimal in-pixel source follower design to reach a sub-0.3erms- read noise at room temperature. This paper also discusses the impact of technology scaling on the CIS read noise. It shows how designers can take advantage of scaling and how the Metal-Oxide-Semiconductor (MOS) transistor gate leakage tunneling current appears as a challenging limitation. For this purpose, both simulation results of the gate leakage current and 1/f noise data reported from different foundries and technology nodes are used.

  12. Upward electron beams measured by DE-1 - A primary source of dayside region-1 Birkeland currents

    NASA Technical Reports Server (NTRS)

    Burch, J. L.; Reiff, P. H.; Sugiura, M.

    1983-01-01

    Measurements made by the High Altitude Plasma Instrument on DE-1 have shown that intense upward electron beams with energies from about 20 eV to about 200 eV are a common feature of the region just equatorward of the morning-side polar cusp. Computations of the currents carried by these beams and by the precipitating cusp electrons show excellent agreement with the simultaneous DE-1 magnetometer measurements for both upward and downward Birkeland currents. The data indicate that cold ionospheric electrons, which carry the downward region-1 Birkeland currents on the morning side, are accelerated upward by potential drops of a few tens of eV at altitudes of several thousand kilometers. This acceleration process allows spacecraft above those altitudes to measure routinely the charge carriers of both downward and upward current systems.

  13. Microbial Source Tracking: Current and Future Molecular Tools in Microbial Water Quality Forensics

    EPA Science Inventory

    Current regulations in the United States stipulate that the microbial quality of waters used for consumption and recreational activities should be determined regularly by measuring microbial indicators of fecal pollution. Hence, the microbial risk associated with these waters is...

  14. Microbial Source Tracking: Current and Future Molecular Tools in Microbial Water Quality Forensics

    EPA Science Inventory

    Current regulations in the United States stipulate that the microbial quality of waters used for consumption and recreational activities should be determined regularly by measuring microbial indicators of fecal pollution. Hence, the microbial risk associated with these waters is...

  15. Upward electron beams measured by DE-1: A primary source of dayside region-1 Birkeland currents

    SciTech Connect

    Burch, J.L.; Reiff, P.H.; Sugiura, M.

    1983-08-01

    Measurements made by the High Altitude Plasma Instrument on DE-1 have shown that intense upward electron beams with energies from roughly-equal20 eV to roughly-equal200 eV are a common feature of the region just equatorward of the morning-side polar cusp. Computations of the currents carried by these beams and by the precipitating cusp electrons show excellent agreement with the simultaneous DE-1 magnetometer measurements for both upward and downward Birkeland currents. The data indicate that cold ionospheric electrons, which carry the downward region-1 Birkeland currents on the morning side, are accelerated upward by potential drops of a few tens of eV at altitudes of several thousand kilometers. This acceleration process allows spacecraft above those altitudes to measure routinely the charge carriers of both downward and upward current systems.

  16. DE 1 observations of theta aurora plasma source regions and Birkeland current charge carriers

    NASA Astrophysics Data System (ADS)

    Menietti, J. D.; Burch, J. L.

    1987-07-01

    Detailed analyses of the DE 1 high-altitude plasma instrument electron and ion data have been performed for four passes during which theta auroras were observed. The data indicate that the theta auroras occur on what appear to be closed field lines with particle signatures and plasma parameters that are quite similar to those of the magnetospheric boundary plasma sheet. The field-aligned currents computed from particle fluxes in the energy range 18-13 keV above the theta auroras are observed to be generally downward on the dawnside of the arcs with a narrower region of larger (higher density) upward currents on the duskside of the arcs. These currents are carried predominantly by field-aligned beams of accelerated cold electrons. Of particualr interest in regions of upward field-aligned current are downward electron beams at energies less than the inferred potential drop above the spacecraft.

  17. DE 1 observations of theta aurora plasma source regions and Birkeland current charge carriers

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Burch, J. L.

    1987-01-01

    Detailed analyses of the DE 1 high-altitude plasma instrument electron and ion data have been performed for four passes during which theta auroras were observed. The data indicate that the theta auroras occur on what appear to be closed field lines with particle signatures and plasma parameters that are quite similar to those of the magnetospheric boundary plasma sheet. The field-aligned currents computed from particle fluxes in the energy range 18-13 keV above the theta auroras are observed to be generally downward on the dawnside of the arcs with a narrower region of larger (higher density) upward currents on the duskside of the arcs. These currents are carried predominantly by field-aligned beams of accelerated cold electrons. Of particualr interest in regions of upward field-aligned current are downward electron beams at energies less than the inferred potential drop above the spacecraft.

  18. Upward electron beams measured by DE-1 - A primary source of dayside region-1 Birkeland currents

    NASA Astrophysics Data System (ADS)

    Burch, J. L.; Reiff, P. H.; Sugiura, M.

    1983-08-01

    Measurements made by the High Altitude Plasma Instrument on DE-1 have shown that intense upward electron beams with energies from about 20 eV to about 200 eV are a common feature of the region just equatorward of the morning-side polar cusp. Computations of the currents carried by these beams and by the precipitating cusp electrons show excellent agreement with the simultaneous DE-1 magnetometer measurements for both upward and downward Birkeland currents. The data indicate that cold ionospheric electrons, which carry the downward region-1 Birkeland currents on the morning side, are accelerated upward by potential drops of a few tens of eV at altitudes of several thousand kilometers. This acceleration process allows spacecraft above those altitudes to measure routinely the charge carriers of both downward and upward current systems.

  19. Perturbation theory for Maxwell's equations with a time-dependent current source

    NASA Astrophysics Data System (ADS)

    Roy, T.; Ghosh, S.; Bhattacharjee, J. K.

    2011-12-01

    Using a set of ideas discussed in the second volume of Feynman Lectures, we develop a perturbation-theoretic scheme for solving Maxwell's equations for time-dependent currents which are switched on at t = 0.

  20. Coulomb collisions of ring current particles: Indirect source of heat for the ionosphere

    NASA Technical Reports Server (NTRS)

    Cole, K. D.

    1975-01-01

    The additional energy requirements of the topside ionosphere during a magnetic storm are less than one quarter of the ring current energy. This energy is supplied largely by Coulomb collisions of ring current protons of energy less than about 20 keV with background thermal electrons which conduct the heat to the ionosphere. Past criticisms are discussed of this mechanism for the supply of energy to the SAR-arc and neighboring regions of the ionosphere.