Atsushi Domae

Johnson Noise Thermometry Based on Integrated Quantum Voltage Noise Source

We performed Johnson noise thermometry (JNT) using an integrated quantum voltage noise source (IQVNS) that generates pseudorandom noise with an RMS value determined by the product of the flux quantum, the clock frequency of IQVNS, fclk, and a calculable coefficient. The working principle is different from the conventional QVNS. The waveform of the IQVNS was analyzed thoroughly, and the source checked to see that it worked properly as intended, particularly in regard to its applicability as a reference for JNT measurements. The thermal noise power of a resistor at the triple point of water was measured with the IQVNS to derive a value of the Boltzmann constant.

Development of a one-chip quantized Hall resistance voltage divider

A resistive voltage divider, which is constructed from a binary segmented series array of quantized Hall resistance (QHR) bars fabricated on one chip, named the ?QHR voltage divider?, has been developed. The QHR voltage divider does not, in principle, require time-consuming bootstrap self-calibration and will provide voltage ratios that are defined by fundamental physical constants with small uncertainties. To evaluate the performance of the QHR voltage divider, the dependence of the Hall resistances RH?of all serial segments on the magnetic flux density was measured. The results of the RH?measurement showed large and well-defined plateaus, and it was confirmed that the fabricated QHR divider in conjunction with a suitable voltage source would function as a voltage divider. From a preliminary test of the voltage ratios of the QHR voltage divider, deviations from nominal ratios were measured to be less than 1.4???10?6, and the expanded uncertainty of the measurement was estimated to be less than 4.1???10?6.

Monitoring of NMIJ standard capacitors during the last 10 years

Air (dry nitrogen) and fused silica standard capacitors have been monitored at NMIJ since 1999. In this paper, we describe the monitoring results of these capacitors and evaluate their behavior.

Development of a voltage divider based on quantized Hall resistance arrays for a high DC voltage standard II

A one-chip quantized voltage divider device based on the technology of integration of quantized Hall resistance (QHR) bars on a GaAs/AlGaAs Heterostructure Substrate has been developed. The first experimental QHR voltage divider device, which consists of a series of 20 QHR bars, has been fabricated. A preliminary test in our evaluation study of the device clearly shows that it functions as a voltage multiplier/divider.

Development of Quadrature Bridge for AC QHR Measurements at Measurement Frequency of 1.592 kHz

A quadrature bridge, one of the important instruments for National Metrology Institute of Japan capacitance measurement chain based on an ac quantized Hall resistance (QHR), has been developed. The developed quadrature bridge can be used to compare the capacitance and ac QHR at a measurement frequency of 1.592 kHz. At the present stage of development, the bridge can be used to achieve a relative standard uncertainty of 0.030 × 10-6 during bridge balancing.

Development of on-chip double-shielded quantum Hall device for use in ac quantized Hall resistance measurement

We have developed a on-chip double-shielded quantum Hall device and a double-shielded chip-carrier. The device in conjunction with the carrier will realize impedance standard based on the quantum Hall effect. In this configuration, the Hall bar is covered by separated on-chip shields and shields of the chip carrier to retrieve the leakage current. In this paper, we show detail of the QHR device fabrication and the structure of the chip carrier.

Calibration of Standard Capacitors of 0.01 - 1 μF at NMIJ/AIST

To provide calibrations of standard capacitors of 0.01-1 muF, a four terminal-pair bridge has been developed. The combined standard uncertainty in the calibration of the 0.01 muF capacitor based on a quantized Hall resistance was estimated to be 0.54times10-6

Development and Evaluation of High-Stability Metal-Foil Resistor With a Resistance of 1

Prototype models of a high-stability metal-foil resistor of 1 kΩ with a four-terminal-pair design were developed, and the key characteristics were evaluated. Two types of metalfoil resistors were fabricated: serial number (s/n) 1 is made from two resistor devices of 500 Ω and s/n 2 is made from three resistor devices of 333 Ω. To develop these resistor devices, a new resistor-device design was introduced. The s/n 1 resistor has the following key characteristics: drift rate: 0.010 (μΩ/Ω)/year, first-order temperature coefficient at 23 °C: -0.165 (μΩ/Ω)/°C, frequency dependence of the resistance (relative change in resistance normalized at 1 kHz): ±0.21 μΩ/Ω in the frequency range from 400 Hz to 2 kHz, and time constant: -0.46 ns. The s/n 2 resistor has the following key characteristics: drift rate: -0.092 (μΩ/Ω)/year, first-order temperature coefficient at 23 °C: 0.096 (μΩ/Ω)/°C, frequency dependence of the resistance (relative change in resistance normalized at 1 kHz): ±0.54 μΩ/Ω in the frequency range from 400 Hz to 2 kHz, and time constant: 0.12 ns.

Development of High-Stability Metal-Foil Standard Resistors for DC and AC Measurements

Abstract: Compact metal-foil standard resistors with four terminals have been developed. The main DC characteristics of the developed 100 Ω resistors are a drift rate of <0.1 (μΩ/Ω)/year, a temperature coefficient of <0.1 (μΩ/Ω)/°C at 23 °C, changes in resistance due to humidity that are negligible or lower than 0.01 (μΩ/Ω) in the 35 % RH to 80 % RH range, and changes in resistance versus the pressure variation that are negligible or lower than 0.025 (μΩ/Ω)/(250 hPa) in the 700 hPa to 1200 hPa range. The power coefficient is negligible based on the quantized Hall resistance when the applied current is lower than 5 mA. The AC performance was also characterized: the frequency dependence is negligible below 2 kHz, and the time constant is 3.7 ns. These excellent characteristics have been achieved by careful optimization of the composition, annealing conditions, and surface treatment of the element materials, and also by a strain-free supporting technique for the resistor elements. The development of the 100 Ω resistors has been completed, and 1 Ω to 10 kΩ resistors are now being developed. Preliminary results for the 10 Ω resistors show a drift rate similar to that of the 100 Ω resistors.

Feasibility study on remote calibration of impedance standard for industrial use

A feasibility study of remote calibration of impedance standards with a view to industrial use was conducted. Verification tests showed that the values obtained by remote calibration agreed with those by hand-carry calibration within the standard uncertainties.