Plenary speakers: Dr. Michael Stock
Michael Stock is a physicist at the International Bureau of Weights and Measures (BIPM) in Sèvres, close to Paris, where he leads the Physical Metrology Department.
He received the diploma in physics from the University of Osnabrück (Germany) in 1989 and the Ph.D. degree from the Technical University of Berlin in 1995.
His professional career started in 1990 at the Physikalisch-Technische Bundesanstalt (PTB), Berlin, where he carried out a comparison of three radiometric primary standards. In 1996, he joined the BIPM, initially working on research and development related to the realization of radiometric and photometric quantities. From 2001 to 2003 he was Head of the Radiometry Section and from 2004 he was responsible for launching the calculable capacitor and the watt balance projects. In July 2007 he became Head of the Electricity Section and since 2015 of the newly created Physical Metrology Department, which includes projects in electricity and mass.
He serves as the Executive Secretary of the Consultative Committee for Electricity and Magnetism (CCEM), which brings together the world’s experts in this field as advisers on scientific and technical matters and is actively involved in the preparations for the planned revision of the SI system.
Topic: Realization and dissemination of the kilogram after its planned redefinition
Since 1889 the international prototype of the kilogram serves as the definition of the unit of mass, the kilogram, in the International System of Units (SI). It is nowadays the last material artefact which defines a base unit of the SI. This definition has the advantage of great conceptual simplicity, but also presents some disadvantages and is no longer considered adequate in a time of ever increasing measurement accuracy.
Resolution 1 adopted by the 25th General Conference on Weights and Measures (CGPM) in 2014 foresees to redefine the kilogram, at the same time as three other base units, the ampere, the kelvin and the mole. The new kilogram definition will be based on a fixed numerical value of the Planck constant, in analogy to the definition of the metre, which is based on a fixed numerical value of the speed of light. These changes are expected to be approved by the 26th CGPM in November 2018 provided that some conditions are met. The Consultative Committee for Mass and Related Quantities (CCM) and the Consultative Committee for Units (CCU) have developed a Roadmap which identifies all necessary steps to achieve this. To ensure that the size of the unit will not change, requires as a first step a highly accurate determination of the numerical value of the Planck constant in the present SI.
Two types of experiments are applied for this purpose: the watt balance (now also called the Kibble balance in homage to Bryan Kibble) and the X-ray crystal density method (XRCD method, using silicon spheres). At present, both types of experiments are used to determine the numerical value of the Planck constant. After the redefinition, they will become methods to realize the kilogram, based on the numerical value of the kilogram which will then be fixed.
An important change with respect to the current situation will be that after the kilogram is redefined, traceability to the definition of the kilogram will, in principle, be available from more than one source, and the consistency of the independent realizations will need to be established.
In the presentation, the plans for the revision of the SI will be presented, with particular focus on the redefinition of the kilogram. An overview will be given of the status of the different steps figuring on the joint CCM-CCU Roadmap. The foreseen future system of mass dissemination will be discussed.
Keywords: SI system, kilogram, mass unit
Plenary speakers: Dr. Alessandro Germak
Alessandro Germak born in Torino, Italy in 1962, since 1983 he is working at INRIM, the National Institute of Metrological Research in Italy, currently as senior researcher. He is responsible for research activities for the keeping and the dissemination of the units of Force and Hardness, and for the primary method to measure the local gravity acceleration.
He is also, since 2000, a contract professor of the Polytechnic di Torino to the course of Experimental Statistics and Mechanical Measurements.
He is an active member of the Working Group on Force, Hardness and Gravimetry (Chairmen) of the Consultative Committee for Mass and related quantities (CCM) of the International Committee of Weights and Measures (CIPM) and of the European Metrology Organization (EURAMET). He also participates in the activities of the International Geodesy Association (IAG) in the working groups related to absolute gravimetry.
Within its research fields, he published about 80 papers on international journals and books and presented about 100 papers at international congresses.
Topic: The effect of the redefinition of the kilogram on its present related quantities
The recent proposal to redefine the kilogram seems to leave unchanged the entire dissemination chain, including the realization of related quantities such as strength, torque, pressure, and so on. This is the slogan that has been circulated in order to make the new definition of the kilogram, as well of the whole new SI, more acceptable.
In fact, once the “mise en pratique” of the realization of the kilogram, like the Kibble Balance, is achieved, a mass standard with its associated uncertainty can be used as a starting point for the realization of, for example, a force standard.
But if we go to analyze the equations that govern the practical realization of the kilogram, we see how some quantities come into play, such as the local gravity acceleration, for which a measurement and an uncertainty estimation is needed. The same quantity must then be taken into consideration again when we have to use the mass for realizing the force quantity (as well torque, pressure, etc.).
Then we can ask if it is not possible to take advantage of the new redefinition of the kilogram and realize a standard of a quantity, related formally from the kilogram, directly through its “mise en pratique”.
Indeed, the equations governing the Kibble balance allow us to realize, by a primary method, not only the mass quantity but also the force quantity, with the advantage of having uncertainty, at least nominally, lower.
Some experiments and practical realizations of such standards have already been carried out, for example in the realization of a torque standard where the traceability to the SI was successfully realized for the first time using a method which does not refer to the gravitational force.
This approach paves the way for future new scenarios where mechanical quantities such as force, torque, pressure, and so on will no longer be related to the mass but only to electrical quantities.
Plenary speakers: Flt. Lt. Tawat Changpan
Flt. Lt. Tawat Changpan received the Bachelor of Arts in Political Science (International Relation) in 1983.
He started his metrological career at the Precision Measuring Equipment Laboratory (PMEL), Directorate of Communication and Electronics, Royal Thai Air force from 1975 to 1993.
He has served as the metrologist in Reference Standard Labs, Technical Department, Thai Airways International (public) Co., Ltd. from 1993 to 1998.
From 1993 to 1998, he joined the National Institute of Metrology (Thailand), or NIMT, as a Head of Pressure and Vacuum Laboratories.
He was an Assistant Head of Mechanical Metrology Department at NIMT (from 2003 to 2013. In 2013, he became a Head of Mechanical Metrology Department and also an Acting Head of Acoustics & Vibration Metrology Department in 2014 until his retirement in 2016.
He has the expertise in the fields of pressure measurement and absolute gravity measurement. He also actively played an important role in the project of development of metrology in medical measuring devices of the country.
Recently, he dedicates his knowledge to provide the technical transfer in pressure metrology to many NMIs, e.g., NML-PHIL (Philippines), NBSM (Nepal), NML-BSTI (Bangladesh), MASM (Mongolia), CSM (Kyrgyz Republic) and MUSSD (Sri Lanka).
Topic: History of Mechanical Metrology Department of National Institute of Metrology (Thailand)
The activity in metrology of mechanical metrology department, National Institute of Metrology (Thailand) / (NIMT); has been started since 1998, in the same year as NIMT founded. The laboratories were located in Bangkok downtown, using the building that belonged to Department of Science Service, Ministry of Science Technology and Environment; as the temporary facility. Mass and pressure were the first 2 laboratories that capable to provide the calibration services to customers. Vacuum, Force and Torque were the next laboratories that have been capable to provide the services. Flow and Hardness laboratories were the third group of serviceable laboratories while Density laboratory was the last one. The local gravity values of 7 points around the country had been measured by the cooperation from National Institute of Metrology (NIM) Beijing. The permanent facility of NIMT was constructed using the loan money project from Japanese government. All equipment of the department was moved to the new facility which is located in Patumthani province in 2005. Due to the technical transferred projects supported from many National Metrology Institutes (NMIs), mainly Physikalisch-Technische Bundesanstalt (PTB) Germany and National Metrology Institute of Japan (NMIJ) Japan; the technical competent and international recognition for all laboratories have been achieved. Service to customers from all laboratories has been provided not only the calibrations of standard equipment but technical trainings and technical consultants have been conducted. Until November 2017 the traceability for the quantities of force, torque, hardness and pressure have been successfully characterized internally and maintained.