CCU: C : Consultativ ive Commit ittee f for U Unit its President: Prof. Dr Joachim Ullrich Executive Secretary: Dr Estefanía de Mirandés Date established: 1964, to replace the "Commission for the System of Units", set up by the CIPM in 1954
CCU: Consultative Committee for Units 23rd meeting of the CCU (2017) • provide advice about units of measurement • develop the International System of Units (SI) • prepare the SI Brochure 1st meeting of the CCU (1967) www.bipm.org 2
CCU: Consultative Committee for Units 23rd meeting of the CCU (2017) Members of the CCU Liaisons of the CCU • 11 National Metrology Institutes • 3 International Unions • 3 Personal members • 5 International Commissions & Committees • 1 Ex officio member • 2 Intergovernmental Organizations or International bodies www.bipm.org 3
CCU: Consultative Committee for Units Global forum for progressing the state-of-the art CCU is the only global forum for units Facilitating dialogue between NMIs and all stakeholders Always through international consensus Global comparability of measurements www.bipm.org 5
Quantities and Measurement Units number unit value of a Q = { Q } [ Q ] artefact quantity m = 10.1 kg v = 87.4 km/h m = 10.1 kg t = 55.4 s www.bipm.org 6
Quantities and Measurement Units number unit value of a Q = { Q } [ Q ] artefact quantity m = 10.1 kg (2) material property measurem. prescription t = 55.4 s (1) defining constant ( 133 Cs) hfs = 9 192 631 770. 5 s -1 ( 6 ) 1 s = 9 192 631 770 constant of nature uncertainty ( 133 Cs) hfs Define a unit by fixing the numerical value of a constant of nature www.bipm.org 7
The International System of Units: SI Base units length Established in 1960: CGPM luminous mass intensity amount of time substance temperature electric current www.bipm.org 8
The International System of Units: SI Base units Derived units with special names Dimensions of quantities A set of coherent SI units Derived units [ v ] = m s -1 [ c ] = mol m -3 www.bipm.org 9
The International System of Units: SI Base units Derived units Dimensions of quantities A set of coherent SI units A global measurement infrastructure Valid world wide • Intensity of light from an LED • CO 2 concentration in the air • Creatinine concentration in blood serum • Dose equivalent outside nuclear reactors • …. www.bipm.org 10
The International System of Units: SI Member participating in the CIPM MRA Associate participating in the CIPM MRA A global measurement infrastructure Valid world wide : CIPM-MRA signed by : CIPM-MRA 97.6 % of the world economy • 101 Member and Associate States • 4 International Organization The cornerstone of international Basis and condition sine qua • Covering 153 Designated Institutes (DI) quality infrastructure (QI) non for world wide trade www.bipm.org 11
The International System of Units: SI 1 m = c arte- c length Redefinitions s 299 792 458 fact - 1967: second mass luminous - 1983: metre - 1990: ohm, volt intensity 2018: ~ 2 × 10 -16 1967: ~10 -14 enters the hfs definition of time amount of substance isolated isolated 1 s = 9 192 631 770 h R 25 813 R ( 133 Cs) hfs R K , K J K K 90 material property 2 e 2 e temperature electric current K 483 598 GHz / V K J J 90 h www.bipm.org 12
The International System of Units: SI length mass luminous intensity …not an ideal situation! time amount of substance temperature electric current www.bipm.org 13
The International System of Units: SI length mass luminous intensity …not an ideal situation! tremendous time amount of benefits of substance quantum-based units temperature electric current electric current www.bipm.org 14
The International System of Units: SI Build a coherent and consistent quantum-based system of units length mass luminous intensity …not an ideal situation! tremendous time amount of benefits of substance quantum-based units temperature electric current www.bipm.org 15
The International System of Units: SI Build a coherent and consistent quantum-based system of units • CIPM Recommendation 1 (CI-2005) mass luminous • Resolution 12 of the 23rd CGPM intensity …not an ideal • Resolution 1 of the 24th CGPM situation! • Resolution 1 of the 25th CGPM tremendous time amount of benefits of substance quantum-based units temperature electric current www.bipm.org 16 …take preparative steps towards new definitions of
The International System of Units: SI Build a coherent and consistent quantum-based system of units • CIPM Recommendation 1 (CI-2005) • Resolution 12 of the 23rd CGPM • Resolution 1 of the 24th CGPM • Resolution 1 of the 25th CGPM …with the help of fundamental constants Resolution 1 of the 26th CGPM we have the possibility of establishing units of length, time, mass, and 13 years and 7 CCU meetings! temperature, which necessarily retain their validity for all times and civilisations, even extraterrestrial and nonhuman… www.bipm.org 17
Defining Constants ν Hyperfine transition 133 Cs c Speed of Light h Planck constant e Elementary charge k Boltzmann constant N A Avogadro constant K cd Luminous Efficacy In the ‚old‘ SI: …for all times and cultures Define the units → Measure the constants of nature (uncertainty) Now in the revised SI: …throughout the universe Fix numerical values of defining constants → Determine the units www.bipm.org 18
Defining Constants Creating the Units Cs = 9 192 631 770 Hz ν Hyperfine transition 133 Cs c Speed of Light Planck constant h Elementary charge e k Boltzmann constant N A Avogadro constant Relative uncertainty: 2 · 10 – 16 Luminous Efficacy …for all times and cultures K cd (1 second in 160 million years) …throughout the universe …for GPS, science,… www.bipm.org 19
Defining Constants Creating the Units c = 299 792 458 m/s Apollo-11-Crew, 1969 2 t = 2,56 ... s d = c · t travel time t 2,56 s 0 s www.bipm.org 20
Defining Constants Creating the Units h = 6.626 070 15 10 -34 Js m = n A m e ( h , c , Cs ) m A / m e Quantum mechanics with the Planck ..count the number of atoms in The Silicon Route a crystal sphere of enriched 28 Si constant gives mass to the atoms www.bipm.org 21
Defining Constants Creating the Units h = 6.626 070 15 10 -34 Js m g v = h K 2 R K /4 J Balance weight with The Kibble Balance electromagnetic force www.bipm.org 22
Defining Constants Creating the Units e = 1.602 176 634 10 -19 C I = n e f Count the flow of electrons in a second www.bipm.org 23
Defining Constants Creating the Units k B = 1.380 649 10 -23 J/K James Joule T v m m g h E kin = (½)m v 2 = ( ) k T 3 2 Energy is proportional to Temperature : ideal gas www.bipm.org 24
Defining Constants Creating the Units N A = 6.022 140 76 10 23 /mol 2 + 1 = 1 m H 2 N A 2 H + 1 O = 1 H 2 O + = N A m O N A m H O 2 If you take N A entities (atoms, molecules) you get 1 mol Multiply with the atomic/molecular masses: molar mass www.bipm.org 25
Defining Constants Creating the Units K cd = 683 lm/W 555 nm 540·10 12 Hz Luminosity function V( ) Spectral luminous efficacy K ( ) night light day light night light K ( ) = K cd V ( ) day light “ K cd brings humanity into metrology” Wavelength www.bipm.org 26
Revised International System of Units A concept improved fundamentally! Guarantees long-time stability A set of “defining constants” establish the units in general www.bipm.org 27
Revised International System of Units A concept improved fundamentally! Guarantees long-time stability A set of “defining constants” establish the units in general Different realisations • Realisation everywhere (Universe…) Key comparisons: safer, less correlations • Atomic masses www.bipm.org 28 “De Broglie” “Photon recoil” “Silicon crystal” “Kibble balance”
Revised International System of Units A concept improved fundamentally! Guarantees long-time stability A set of “defining constants” establish the units in general Different realisations Realisation everywhere (Universe…) Often throughout the entire scale • Acoustic gas thermometry • Dielectric constant gas thermometry • Doppler thermometry • Noise thermometry • Radiation thermometry www.bipm.org 29
Revised International System of Units A concept improved fundamentally! Guarantees long-time stability A set of “defining constants” establish the units in general Different realisations Realisation everywhere (Universe…) Often throughout the entire scale Base units are only a convention Direct realisation of - the ohm - the volt - the ampere - the coulomb www.bipm.org 30
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