scholarly journals The NIST Johnson Noise Thermometry System for the Determination of the Boltzmann Constant

2017 ◽  
Vol 122 ◽  
Author(s):  
Nathan E. Flowers-Jacobs ◽  
Alessio Pollarolo ◽  
Kevin J. Coakley ◽  
Adam C. Weis ◽  
Anna E. Fox ◽  
...  
Keyword(s):  
International System ◽  
Standard Uncertainty ◽  
Boltzmann Constant ◽  
Correlated Noise ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Relative Standard ◽  
System Of Units ◽  
Johnson Noise Thermometry

In preparation for the redefinition of the International System of Units (SI), five different electronic measurements of the Boltzmann constant have been performed using different Johnson noise thermometry (JNT) systems over the past seven years. In this paper, we describe in detail the JNT system and uncertainty components associated with the most recent National Institute of Standards and Technology (NIST) determination of the Boltzmann constant: k = 1.380642 9(69) × 10−23 J/K, with a relative standard uncertainty of 5.0 × 10−6 and relative offset of −4.05 × 10−6 from the Committee on Data for Science and Technology (CODATA) 2014 recommended value. We discuss the input circuits and the approach we used to match the frequency response of two noise sources. We present new measurements of the correlated noise of the 4 K on-chip resistors in the quantum-accurate, pseudorandom, voltage-noise source, which we used to estimate the correlated, frequency-dependent, nonthermal noise in our system. Finally, we contrast our system with those used in other measurements and speculate on future improvements.

scholarly journals An improved electronic determination of the Boltzmann constant by Johnson noise thermometry

Metrologia ◽  
2017 ◽  
Vol 54 (4) ◽  
pp. 549-558 ◽  
Author(s):  
Jifeng Qu ◽  
Samuel P Benz ◽  
Kevin Coakley ◽  
Horst Rogalla ◽  
Weston L Tew ◽  
...  
Keyword(s):  
Boltzmann Constant ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Johnson Noise Thermometry

scholarly journals Improved electronic measurement of the Boltzmann constant by Johnson noise thermometry

Metrologia ◽  
2015 ◽  
Vol 52 (5) ◽  
pp. S242-S256 ◽  
Author(s):  
Jifeng Qu ◽  
Samuel P Benz ◽  
Alessio Pollarolo ◽  
Horst Rogalla ◽  
Weston L Tew ◽  
...  
Keyword(s):  
Boltzmann Constant ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Electronic Measurement ◽  
Johnson Noise Thermometry

Boltzmann Constant Measurements Using QVNS-Based Johnson Noise Thermometry at NMIJ, AIST

2014 ◽  
Vol 35 (6-7) ◽  
pp. 985-998 ◽  
Author(s):  
K. Yamazawa ◽  
C. Urano ◽  
T. Yamada ◽  
T. Horie ◽  
S. Yoshida ◽  
...  
Keyword(s):  
Boltzmann Constant ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Johnson Noise Thermometry

scholarly journals Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

2011 ◽  
Vol 369 (1953) ◽  
pp. 4014-4027 ◽  
Author(s):  
Laurent Pitre ◽  
Fernando Sparasci ◽  
Daniel Truong ◽  
Arnaud Guillou ◽  
Lara Risegari ◽  
...  
Keyword(s):  
Molar Mass ◽  
Thermodynamic Temperature ◽  
Standard Uncertainty ◽  
Acoustic Resonator ◽  
Diamond Turning ◽  
Boltzmann Constant ◽  
Triple Point Of Water ◽  
Resonance Frequencies ◽  
Relative Standard

The paper reports a new experiment to determine the value of the Boltzmann constant, , with a relative standard uncertainty of 1.2 parts in 10 6 . k B was deduced from measurements of the velocity of sound in argon, inside a closed quasi-spherical cavity at a temperature of the triple point of water. The shape of the cavity was achieved using an extremely accurate diamond turning process. The traceability of temperature measurements was ensured at the highest level of accuracy. The volume of the resonator was calculated from measurements of the resonance frequencies of microwave modes. The molar mass of the gas was determined by chemical and isotopic composition measurements with a mass spectrometer. Within combined uncertainties, our new value of k B is consistent with the 2006 Committee on Data for Science and Technology (CODATA) value: ( k new B / k B_CODATA −1)=−1.96×10 −6 , where the relative uncertainties are and u r ( k B_CODATA )=1.7×10 −6 . The new relative uncertainty approaches the target value of 1×10 −6 set by the Consultative Committee on Thermometry as a precondition for redefining the unit of the thermodynamic temperature, the kelvin.

scholarly journals Towards an Optical Gas Standard for Traceable Calibration-Free and Direct NO2 Concentration Measurements

2021 ◽  
Vol 11 (12) ◽  
pp. 5361
Author(s):  
Javis A. Nwaboh ◽  
Zhechao Qu ◽  
Olav Werhahn ◽  
Volker Ebert
Keyword(s):  
International System ◽  
Line Strength ◽  
Reference Method ◽  
Standard Uncertainty ◽  
Tunable Diode Laser ◽  
Relative Standard ◽  
System Of Units ◽  
Gas Standard ◽  
Calibration Free ◽  
Concentration Measurements

We report a direct tunable diode laser absorption spectroscopy (dTDLAS) instrument developed for NO2 concentration measurements without chemical pre-conversion, operated as an Optical Gas Standard (OGS). An OGS is a dTDLAS instrument that can deliver gas species amount fractions (concentrations), without any previous or routine calibration, which are directly traceable to the international system of units (SI). Here, we report NO2 amount fraction quantification in the range of 100–1000 µmol/mol to demonstrate the current capability of the instrument as an OGS for car exhaust gas application. Nitrogen dioxide amount fraction results delivered by the instrument are in good agreement with certified values of reference gas mixtures, validating the capability of the dTDLAS-OGS for calibration-free NO2 measurements. As opposed to the standard reference method (SRM) based on chemiluminescence detection (CLD) where NO2 is indirectly measured after conversion to NO, titration with O3 and the detection of the resulting fluorescence, a dTDLAS-OGS instrument has the benefit of directly measuring NO2 without distorting or delaying conversion processes. Therefore, it complements the SRM and can perform fast and traceable measurements, and side-by-side calibrations of other NO2 gas analyzers operating in the field. The relative standard uncertainty of the NO2 results reported in this paper is 5.1% (k = 1, which is dominated (98%) by the NO2 line strength), the repeatability of the results at 982.6 µmol/mol is 0.1%, the response time of the instrument is 0.5 s, and the detection limit is 825 nmol/mol at a time resolution of 86 s.

scholarly journals A Boltzmann constant determination based on Johnson noise thermometry

Metrologia ◽  
2017 ◽  
Vol 54 (5) ◽  
pp. 730-737 ◽  
Author(s):  
N E Flowers-Jacobs ◽  
A Pollarolo ◽  
K J Coakley ◽  
A E Fox ◽  
H Rogalla ◽  
...  
Keyword(s):  
Boltzmann Constant ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Constant Determination ◽  
Johnson Noise Thermometry

scholarly journals Realization of an SI traceable small force of 10 to 100 micro-Newton using an electrostatic measuring system

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 4 ◽  
Author(s):  
Jile Jiang ◽  
Gang Hu ◽  
Zhimin Zhang
Keyword(s):  
Laser Interferometer ◽  
International System ◽  
Feedback System ◽  
Standard Uncertainty ◽  
Measuring System ◽  
Flexure Hinge ◽  
Relative Standard ◽  
System Of Units ◽  
Capacitance Bridge ◽  
Small Force

<p><span lang="EN-US">A small force of (10</span><span lang="EN-US">–</span><span lang="EN-US">100) micro-Newton traceable to the International System of Units (SI) has been realized using</span><span lang="EN-US"> an</span><span lang="EN-US"> electrostatic </span><span lang="EN-US">measuring system</span><span lang="EN-US"> at the National Institute of Metrology, China. The key component of the measuring system is a pair of coaxial cylindrical electrodes. The inner electrode is suspended with the support of a self-balanced flexure hinge, while the outer electrode is attached to a piezoelectric moving stage. The stiffness of the self-balanced flexure hinge was also designed so as to be both sufficiently stable and sensitive to the small force applied to the inner electrode. Two sets of cameras were </span><span lang="EN-US">used</span><span lang="EN-US"> to capture the shape of the electrodes and to obtain a better coaxial arrangement of the inner and outer electrodes. With the help of a capacitance bridge and a piezoelectric moving stage, the relative standard uncertainty of the capacitance gradient does not exceed 0.04 %. Associated with a laser interferometer and a DC voltage power source, the feedback system that controls the position of the inner electrode is responsible for the generation of a force of 10–100 micro-Newton. The standard uncertainty associated with the force of 100 micro-Newton does not exceed 0.1 %.</span></p>

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