Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session G10: Detectors, Sensors, and Transducers |
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Sponsoring Units: GIMS Chair: Roger Proksch, Asylum Research Room: 108 |
Tuesday, March 3, 2020 11:15AM - 11:27AM |
G10.00001: Semiconductor Particle Detector based on Work Function Modulation Elaine Rhoades, William Hunt, Aaron Green A novel type of solid state particle detector has been designed and investigated. The essential design is a bandgap reference circuit with a Schottky diode comprised of gallium nitride, a semiconducting piezoelectric material, designed to output the Schottky barrier height. As a semiconductor, this material exhibits an electrical response to high-energy particle impingement through the creation of electron-hole pairs. It also exhibits an additional and very unique type of response to lattice vibrations induced in the crystal lattice by momentum transfer from the incident particle. These acoustic waves create mechanical strain which induces an in-phase signal via the piezoelectric effect, which subsequently modulates the effective barrier height of the Schottky diode. This talk presents functional demonstration of a prototype circuit and transient responses to neutron irradiation. |
Tuesday, March 3, 2020 11:27AM - 11:39AM |
G10.00002: Characterizaion of Micro-Magnets on Mechanical Oscillators, and Other Sensors Using Fiber-Optic Interferometry* Peter W. Kampschroeder, Sierra M Casten, Nimisha Ramprasad, Allen C. Wen, Scott S. Williams, John T. Markert We report the design, construction, and use of a fiber-optic interferometer system with variable applied dc and ac magnetic fields and magnetic field gradients for the characterization of micro-magnets on oscillators. The system has measured calibrated displacements to determine resonant frequencies (~1–800 kHz), quality factors (~100–8000), amplitudes, and spring constants (~0.01 N/m) of resonances. Thermal-noise-driven data determined spring constants. The driven response to ac magnetic field gradients (amplitudes ~0.4–40 x10–4 T/m) provided direct measurement of magnetic moments. E.g., for a ~45±5-µm-diameter permalloy sphere, we measure a magnetic moment of 2.8±0.1 x10–8 J/T, in agreement with the expected saturation moment of 3.1±0.6 x10–8 J/T. Characterization of these micro-magnets supports our nuclear magnetic resonance force microscopy (NMRFM) studies. In addition to NMRFM, other ongoing work involving fiber-optic interferometry includes its use in integrated, narrow (~0.2–2 mm Φ) oscillator-fiber sensors for placement in thin channels (e.g., for fast, local quench detection) and its use in a fast-response pressure sensor for operation under extreme (jet/rocket engine) conditions. |
Tuesday, March 3, 2020 11:39AM - 11:51AM |
G10.00003: Secondary Electron Count Imaging in a Scanning Electron Microscope Akshay Agarwal, John Simonaitis, Vivek Goyal, Karl Berggren We have implemented secondary electron (SE) count imaging on a Zeiss LEO 1525 scanning electron microscope (SEM). We established the signal level of single SEs using two methods – image histograms and oscilloscope outcoupling. In both methods, we imaged a uniform sample of aluminum at low beam currents (< 5 pA) and pixel dwell times between 500 ns and 7 μs using both the in-chamber and in-lens SE detectors. In the first method, histograms of the sample images showed distinct peaks corresponding to the number of SEs emitted from each pixel. We used these peaks to establish the single SE signal level and calculated the detective quantum efficiency of our detectors. In the second method, we outcoupled the signal from our SE detectors to a 2 GHz oscilloscope. The output signal trace showed a sequence of pulses of mean duration 180 ns, corresponding to single SEs. Histograms of the total area of the output signal matched the image histograms for the same pixel dwell time. Finally, we synchronized data capture on the oscilloscope with the SEM scan signal to generate SE count images, which showed an improved signal-to-noise ratio compared to conventional images. |
Tuesday, March 3, 2020 11:51AM - 12:03PM |
G10.00004: Bio-Inspired MEMS Direction Finding Underwater Acoustic Sensor Operating in Neutral-Buoyant Configuration Leland McCarty, Jaehyun Park, Fabio Alves, Gamani Karunasiri MEMS acoustic sensors were developed based on the mechanically coupled auditory structure of the Ormia Ochracea fly in order to enhance underwater directional sound-sensing technologies. MEMS directional acoustic sensors consists of two wings connected by a bridge in the middle. The entire mechanical structure is connected to a substrate using two torsional legs. The mechanical vibrations under sound excitation is transduced to an electrical signal using interdigitated comb finger capacitors attached to the edges of the wings. This presentation covers the design, fabrication, and characterization of Ormia-based MEMS directional acoustic sensor operated underwater as an inertial sensor. The sensors were designed using FE modeling tools and fabricated using commercially available MEMSCap SOIMUMPS processes. Characterization was performed in air and underwater, showing the predicted frequency and directional responses. For underwater operation, the sensors were housed in a near-neutral-buoyant, hermetically sealed enclosure. Results indicate that the MEMS acoustic sensor’s microphone characteristics are preserved when operated as accelerometers, and they have a great potential to be used for underwater applications in a neutral-buoyant configuration. |
Tuesday, March 3, 2020 12:03PM - 12:15PM |
G10.00005: New system for high sensitivity study of magnetoelectric effects Ali Sirusi, Marc Lewkowitz, Johnny Adams, Ruyang Sun, Neil Sullivan We report a novel experimental technique for studying magnetoelectric couplings in matter using a tunnel diode to power a specially designed coil cell. The system can detect small changes in frequency of 0.5 ppm, allowing precise measurement of magnetic susceptibility induced by an applied electric field. This system operates over a temperature range from 1.8 K to 100 K, while maintaining the tunnel diode at superfluid helium temperature. The aim of this device is to study magnetoelectric couplings in molecular magnets and spin crossover systems. |
Tuesday, March 3, 2020 12:15PM - 12:27PM |
G10.00006: Performance of superconducting nanowire single photon detectors in strong magnetic fields Tomas Polakovic, Volodymyr Yefremenko, john pearson, Whitney Armstrong, Zein-Eddine Meziani, Kawtar Hafidi, Goran Karapetrov, Valentyn Novosad Superconducting nanowire single photon detectors (SNSPD) have found applications in many fields, including nanophotonics, quantum communication and computing. There is potential in applications in high energy physics, but operation in high magnetic fields is required. |
Tuesday, March 3, 2020 12:27PM - 12:39PM |
G10.00007: High Sensitivity Photodetector Based on Graphene-Germanium Quantum Dot Yifei Wang, Ho Vinh, Prashant Pradhan, Daniel Seitz, Michael P. Cooney, Vinh Q Nguyen Graphene has shown great potential for realizing optoelectronic devices, especially for photodetectors. Here, we experimentally demonstrate a fabrication of photodetector based on graphene-germanium quantum dots that can detect a broadband spectrum from visible to infrared region. The device, based on graphene-germanium quantum dots, demonstrates an improved responsivity and response time. Characteristically, the fabricated photodetector shows a responsivity of 1,500 A/W at room temperature and a fast photoresponse time in the order microseconds. The results address key challenges for broadband photodetectors in the visible to infrared region, and also are promising for the development of graphene-based optoelectronic applications. |
Tuesday, March 3, 2020 12:39PM - 12:51PM |
G10.00008: Advanced thermal readout techniques for ac voltage metrology Joseph Hagmann, Nikolai Klimov, Jason M Underwood, Stefan Cular One of the most accurate methods for quantifying ac voltage amplitude to compare the rms amplitude of an ac waveform to an equivalent dc voltage using a device called a multi-junction thermal converter (MJTC). The MJTC produces a dc output voltage in response to the temperature rise from Joule heating due to electrical power dissipation in a resistive heater. The uncertainty of an MJTC measurement is about 1 µV/V (1 ppm) for voltages in the range of 0.5 V to 10 V and frequencies in the range of 40 Hz to 20 kHz. Conventionally, the rise in temperature due to Joule heating is measured on the MJTC by an array of thermocouples. Although well-established, this type of readout suffers is made challenging by the relatively large resistance (~10kΩ) of the thermocouple array, and the low (several mV) thermovoltage. Here, we present our research into alternative measurement techniques based on physical phenomena such as infrared emission, superconductivity, and photonics in order to achieve improved stability and sensitivity and to extend the voltage and frequency range in which the measurement is accurate, bridging fundamental research with the engineering problems of harnessing useful physics to achieve advanced measurement technology. |
Tuesday, March 3, 2020 12:51PM - 1:03PM |
G10.00009: Measurement of Alzheimer’s Enzymes at Physiological Concentrations with Solid-State Dual-Gate 2D-MoS2 Transistors Son Le, Nicholas B. Guros, Niranjana Amin, Harish C Pant, Arvind Balijepalli, Curt Richter
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Tuesday, March 3, 2020 1:03PM - 1:15PM |
G10.00010: Twin slot antenna coupled graphene THz heterodyne mixer Jayaprakash Poojali, Francois Joint, Ashraf Ali, Kevin Daniels, THOMAS E. MURPHY, Howard Drew The unique hot electron properties of graphene make it an ideal platform for terahertz (THz) heterodyne mixers. However, prior graphene-based heterodyne mixers are designed to operate at cryogenic temperatures and show poor performance above 4 K. In this work, we describe the design of a room temperature graphene based heterodyne mixer optimized to work in the THz spectral range of interest to space based astronomy. The proposed mixer is coupled to a twin slot antenna and a coplanar waveguide transmission line with an impedance matching network. Numerical simulation predicts that the coupling efficiency of the incoming radiation to the graphene mixer is over 90% at 1 THz. The mixer has a predicted intermediate frequency bandwidth of 100 GHz with 90% coupling efficiency. Further, the proposed optimized antenna can match graphene device impedances from 70 Ω – 250 Ω by optimizing the slot width of the antenna. Epitaxial grown quasi- free-standing graphene on silicon carbide substrate was used and it is integrated with a silicon lens. We are currently characterizing the IF mixing bandwidth of our heterodyne mixer at various temperatures and plan to calibrate its sensitivity. |
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