H. Parks

• Doctor of Philosophy
• Group Leader at National Research Council Canada

This paper presents an improved system for traceable calibrations of weld current monitors/testers at short duration high pulsed currents developed recently at the Instituto Nacional de Tecnología Industrial (INTI) in Argentina. The calibration system has an increased capability of generating short duration high pulsed currents of up to 25 kA, and...

Electric power systems have been designed to operate under sinusoidal voltage and current conditions at power frequencies, mainly 50 Hz and 60 Hz, and by far most electrical energy transmission occurs at 50 Hz and 60 Hz. Electric utilities are responsible for providing a sinusoidal voltage to their residential, commercial and industrial customers....

The paper describes the recent development of a system for calibration of electrical instruments with harmonics measurement capability, such as revenue meters and power analyzers, under non-sinusoidal test conditions at National Research Council (NRC) Canada. The improvements implemented with respect to an earlier NRC calibration system are aimed a...

A synchronized current-comparator bridge for calibrating analog merging units at power frequencies of 60 and 50 Hz is described. Analog merging units take analog signals from instrument transformers, convert them into digital form, pack the sampled values into Ethernet frames conforming to the IEC 61850-9-2 LE specification, and stream the frames t...

DOI:https://doi.org/10.1103/PhysRevLett.122.199901

A comparison of two systems based on different methods for calibration of current transformers at several different transformation ratios, burdens, and power frequencies of 60 Hz and 50 Hz is performed at the National Research Council of Canada. The obtained discrepancies in ratio and phase errors are within 5 μA/A and μrad, respectively, for small...

A comparison of two systems based on different methods for calibration of current transformers at a number of different transformation ratios and power frequencies of 60 Hz and 50 Hz at the National Research Council (NRC) of Canada is described. The obtained discrepancies in ratio and phase errors are within a few μA/A for small test currents, and...

This paper describes a development of a calibration system at National Research Council (NRC) Canada for digital bridges, which are in turn used for calibrations of non-conventional current transformers. A pre-calculated set of digital data is generated in accordance with the IEC 61850-9-2 LE specification for data transmission in power substations...

High-voltage DC measurements, from 10 kV up to several hundred kV, are usually traceable through resistive dividers which have a divider ratio on the order of 10,000–100,000. The reference step method [3 M. D. Early, M. Sira, B.-O. Andersson, L. A. Christian, O. Gunnarsson, K.-E. Rydler, and J. Streit, “A simple build-up method for the DC voltage s...

The 10th North American Josephson voltage standard (JVS) interlaboratory comparison (ILC) at 10 V was completed in 2014. This ILC was unique because it consisted of two parts. An on-site comparison was conducted between the National Institute of Standards and Technology (NIST) transportable JVS and the pivot laboratory's conventional JVS (CJVS) sys...

We present a detailed account of our 2004 experiment to measure the Newtonian constant of gravitation with a suspended laser interferometer. The apparatus consists of two simple pendulums hanging from a common support. Each pendulum has a length of 72 cm and their separation is 34 cm. A mirror is embedded in each pendulum bob, which then in combina...

This paper is a complement to the two short papers published in 2001 and 2013 in which we presented the results of the two BIPM determinations of the Newtonian constant of gravitation G. While this review contains no new results, it includes more detailed descriptions of certain key parameters that enter into the determination of G. Following a des...

DOI:https://doi.org/10.1103/PhysRevLett.113.039901

The ninth North American Josephson voltage stan-dard (JVS) interlaboratory comparison (ILC) at 10 V was com-pleted in 2011. An on-site comparison was conducted between the National Institute of Standards and Technology compact JVS and the pivot laboratory system. A set of four traveling Zener voltage standards was then shipped from the pivot labora...

This Letter describes new work on the determination of the Newtonian constant of gravitation, G, carried out at the BIPM since publication of the first results in 2001. The apparatus has been completely rebuilt and extensive tests carried out on the key parameters needed to produce a new value for G. The basic principles of the experiment remain th...

The Ground-Based Nuclear Explosion Monitoring Research and Development (GNEM R&D) program at Sandia National Laboratories (SNL) is regarded as a primary center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for nuclear explosion monitoring. In the area of Infrasound sensor evaluation, Sandia relies on th...

This paper describes new work on the BIPM G experiment carried out since publication of the first results in 2001. The apparatus has been completely rebuilt and extensive tests carried out on the key parameters needed to produce a new value for G. The basic principles of the experiment remain the same, namely a torsion balance suspended from a wide...

The National Conference of Standard Laboratories International (NCSLI) started its 9th Josephson Voltage Standard (JVS) Interlaboratory Comparison (ILC) in March 2011. Sandia National Laboratories (SNL) is the pivot laboratory for this comparison of JVS systems that are currently in operation at several U.S. companies and national laboratories. In...

Josephson voltage standards (JVS) provide a highly accurate representation of the volt. Although the Josephson Effect provides an intrinsic standard of voltage, intercomparisons between different systems are important to insure that potential sources of systematic error are under control and to provide an explicit link to the volt as maintained by...

We determined the Newtonian constant of gravitation G by interferometrically measuring the change in spacing between two free-hanging pendulum masses caused by the gravitational field from large tungsten source masses. We find a value for G of (6.672 34±0.000 14)×10(-11)  m3  kg(-1)  s(-2). This value is in good agreement with the 1986 Committee on...

This paper gives the final results of the Mk II version of the BIPM torsion-balance G experiment. Results of the Mk I version were published in 2001 and the apparatus was entirely rebuilt in the years 2001 to 2003. The key feature the BIPM approach is that a value of G can be obtained by up to three different methods. The 2001 result came from two...

The seventh interlaboratory comparison of Josephson voltage standards (JVS) at 10 V, sponsored by the National Conference of Standard Laboratories International, took place from April to October 2005 with 15 participating laboratories. A traveling JVS system of the National Institute of Standards and Technology was used to make five comparisons wit...

Just over two hundred years ago in his most celebrated publication Henry Cavendish began the description of his experiment with the words, ``the apparatus is very simple.'' Today the techniques for determining G remain simple in principle. Yet in practice these experiments still present some of the most difficult challenges in precision measurement...

The BIPM torsion-strip balance used to produce a value for G published in 2001 has been modified with a view to reducing the uncertainty from the 2001 value of about 40 ppm down to about 10 ppm. The poster will not contain a new value for G

We are completing an experiment to measure the Newtonian constant of gravitation, G, with a suspended Fabry-Perot laser interferometer. The apparatus is operational and systematic errors have been found and eliminated. A result for G is hoped for in summer 2004 with an accuracy of roughly 30 ppm

Reports progress of a programme to measure the Newtonian constant of gravitation, G, with a torsion strip balance using several different methods. We have recently published a result with an uncertainty of 41 parts per million (ppm). The present efforts are aimed at reducing this uncertainty to about 10 ppm.

Of all the fundamental constants of nature, the Newtonian constant of gravitation, G, has been one of the most difficult to measure. The current CODATA value of G has an uncertainty of 1.5 parts in 1000. Although recent experiments have produced values with uncertainties smaller than this, the adopted CODATA uncertainty reflects the fact that there...

Of all the fundamental constants of nature, the Newtonian constant of gravitation, G, has been one of the most difficult to measure. The current CODATA value of G has an uncertainty of 1.5 parts in 1000. Although recent experiments have produced values with uncertainties smaller than this, the adopted CODATA uncertainty reflects the fact that there...

Progress is reported on an experiment to measure the Newtonian constant of gravitation G with a suspended Fabry-Perot laser interferometer. With this technique, we measure the deflection of simple pendulums due to the gravitational attraction of tungsten masses. A result for G is expected with a relative uncertainty of 3×10^-5

An experimental investigation is performed to determine the initial- and final-state alignment effects in the energy-pooling process Ca(4s4p3P1)+Ca(4s4p3P1)→Ca(4s4p1P1)+Ca(4s2). This paper represents a type of four-vector correlation experiment, where two aligned atoms collide and the alignment of the final excited state is observed. The initial Ca...

Alignment and orientation effects in the energy pooling process, Sr(5s5p 3P1) + Sr(5s5p 3P1) → Sr(5s5p 1P1) + Sr(5s2 1S0), are studied in a single atomic beam. The Sr atoms are prepared in an aligned initial state with a polarized laser, and alignment information is extracted by observing the fluorescence from the final Sr(5s5p 1P1) state as the at...

A pulsed laser investigation is performed to study the detailed effects of electronic angular-momentum alignment on the cross section for the energy-transfer process Ca(4s4p 3P1) + Ca(4s4p 3P1) →Ca(4s4p 1P1) + Ca(4s2). A uniform magnetic field imposed by a set of Helmholtz coils is used to systematically precess the initial state orbitals with a we...

A detailed experimental study of the effects of initial Ca(4s4s ^3P_1) state polarization and the resulting final Ca(4s4p ^1P_1) state polarization in Calcium energy pooling is described. The initial state is aligned when it is excited from the ground state by a polarized laser pulse. Large periodic modulations in the energy pooling cross section a...

An experimental investigation is carried out to study the effects of electronic angular momentum alignment and orientation in the energy pooling processes: Ca(4s4p 3 P1) + Ca(4s4p 3P1)-->Ca(4s4 p 1P1) + Ca(4 s2) and Sr(5s5p 3P1) + Sr(5s5 p 3P1) --> Sr(5 s5p 1P1) + Sr(5s2). First three vector correlation experiments are performed, where both initial...

The formation of Ca{sup +} ions is measured in an effusive Ca beam by exciting through either the 4{ital s}4{ital p}{sup 1}{ital P}{sub 1} or the 4{ital s}5{ital p}{sup 1}{ital P}{sub 1} state to highly excited Ca{asterisk}(4{ital snd}{sup 1}{ital D}{sub 2}) Rydberg states. In agreement with previous work by McLaughlin and Duquette [Phys. Rev. Lett...

The formation of Ca+ ions is measured in an effusive Ca beam by exciting through either the 4s4p 1P1 or the 4s5p 1P1 state to highly excited Ca*(4 snd 1D2) Rydberg states. In agreement with previous work by McLaughlin and Duquette [Phys. Rev. Lett. 72, 1176 (1994)], when the Rydberg states are accessed through the 4s5p 1P1 state, we detect a large...