The document discusses the new SI system of measurement units. It provides background on the development of measurement standards over time. Key points: - The current SI system is being revised to define several base units like the kilogram in terms of fundamental physical constants rather than physical artifacts. - Several units like the second, meter and ampere are now defined in terms of fundamental properties of nature like the speed of light, atomic transitions, and charge of an electron. - The kilogram will be defined in terms of the Planck constant, linking it to quantum phenomena. This will eliminate reliance on a physical kilogram artifact held in France. - Precise measurement techniques involving things like silicon spheres or the w

1. Uusi
mittayksikköjärjestelmä
Heikki Isotalo
Johtaja

2. MIKES-metrologia Heikki Isotalo
"If you can't measure it - you can't improve it"
Lord William Thomson Kelvin

3. MIKES-metrologia Heikki Isotalo
Mittatekniikan keskus (MIKES)
Henkilökunta 8Henkilökunta 60

4. MIKES-metrologia Heikki Isotalo

5. MIKES-metrologia Heikki Isotalo
James Clerk Maxwell (1870):
”Jos aiotaan luoda pituuden, ajan tai massa mittanormaaleja,
jotka ovat täydellisen pysyviä, niitä ei pidä etsiä planeettamme
koosta, liikkeestä tai massasta, vaan pilaantumattomien,
muuttumattomien ja täydellisten samanlaisten atomien
aallonpituudesta, värähtelyn jaksosta ja absoluuttisesta massasta”

6. MIKES-metrologia Heikki Isotalo
NykyinenNykyinen mittayksikkmittayksikkööjjäärjestelmrjestelmää

7. MIKES-metrologia Heikki Isotalo
UusiUusi mittayksikkmittayksikkööjjäärjestelmrjestelmää

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Uusi mittayksikköjärjestelmä

9. MIKES-metrologia Heikki Isotalo
Conférence générale des poids et mesures
- 2011 – 2015 – 2019 -
55 États Membres du BIPM, et 37 Associés à la Conférence générale

10. MIKES-metrologia Heikki Isotalo
10
Metri konventio
Finnish members:
1953-1971 Yrjö Väisälä
1992-1998 Olli Lounasmaa
MIKES is member in
CC for Length,
CC for Electricity and
Magnetism, CC for
Thermometry, and
CC for Photo- and
Radiometry

11. MIKES-metrologia Heikki Isotalo
Nykyiset määritelmät
metre (m) The metre is the length of the path travelled by light in vacuum during a time interval of
1/299 792 458 of a second.
kilogram
(kg)
The kilogram is the unit of mass; it is equal to the mass of the international prototype of
the kilogram.
second (s) The second is the duration of 9 192 631 770 periods of the radiation corresponding to
the transition between the two hyperfine levels of the ground state of the caesium 133
atom.
ampere (A) The ampere is that constant current which, if maintained in two straight parallel
conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in
vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per
metre of length.
kelvin (K) The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the
thermodynamic temperature of the triple point of water.
mole (mol) The mole is the amount of substance of a system which contains as many elementary
entities as there are atoms in 0.012 kilogram of carbon 12. When the mole is used, the
elementary entities must be specified and may be atoms, molecules, ions, electrons,
other particles, or specified groups of such particles.
candela (cd) The candela is the luminous intensity, in a given direction, of a source that emits
monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity
in that direction of 1/683 watt per steradian.

12. MIKES-metrologia Heikki Isotalo
The kilogram, ????? unit ofass; its magnitude is set by fixing the numerical
value of the Planck constant to be equal to exactly 6.626 06X × 10−34 when it is
expressed in the unit s−1 m2 kg, which is equal to J s.
Mikä suure?

13. MIKES-metrologia Heikki Isotalo
The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical
value of the Planck constant to be equal to exactly 6.626 06X × 10−34 when it is
expressed in the unit s−1 m2 kg, which is equal to J s.
Mikä suure? kg

14. MIKES-metrologia Heikki Isotalo
Uudet määritelmät
second (s) The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground
state hyperfine splitting frequency of the caesium 133 atom, at rest and at a temperature of 0 K,
to be equal to exactly 9 192 631 770 when it is expressed in the unit s−1, which is equal to Hz.
metre (m) The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed
of light in vacuum to be equal to exactly 299 792 458 when it is expressed in the unit m s−1.
kilogram (kg) The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the
Planck constant to be equal to exactly 6.626 06X × 10−34 when it is expressed in the unit
s−1 m2 kg, which is equal to J s.
ampere (A) The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of
the elementary charge to be equal to exactly 1.602 17X × 10−19 when it is expressed in the unit
A s, which is equal to C.
kelvin (K) The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the
numerical value of the Boltzmann constant to be equal to exactly 1.380 6X × 10−23 when it is
expressed in the unit s−2 m2 kg K−1, which is equal to J K−1.
mole (mol) The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be
an atom, molecule, ion, electron, any other particle or a specified group of such particles; its
magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly
6.022 14X × 1023 when it is expressed in the unit mol−1.
candela (cd) The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by
fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540
× 1012 Hz to be equal to exactly 683 when it is expressed in the unit s3 m−2 kg−1 cd sr, or cd sr
W−1, which is equal to lm W−1.

15. MIKES-metrologia Heikki Isotalo
Kilon prototyyppi
• Pt (90%) / Ir (10%) sylinteri d ≈ h ≈ 39 mm säilytetään
BIPM:ssä lähellä Pariisia.
• Tehty 1889; identtiset kopiot tehty samaan aikaan
• Suomen kopio on no. 23 (ostettu BIPM:stä 1890)
• Massan muutokset ovat olleet yli 100 μg (0.1 ppm)
100 vuoden aikana.
SUOMI

16. MIKES-metrologia Heikki Isotalo
BIPM

17. MIKES-metrologia Heikki Isotalo
Piipallo – kg 1/2
• Lasketaan atomien lukumäärä yksikiteisessä
piipallossa
• Käytetään 28Si (99,995%) ; isotooppisuhde
on suurin mittausepävarmuuden lähde
PTB Annual Report 2012

18. MIKES-metrologia Heikki Isotalo
Wattivaaka kg 2/2
Punnitus Liike
mg = -I dΦ/dz U = -v dΦ/dz
Mitataan kuinka suuri sähkövirta
tarvitaan kelaan, jotta maan
gravitaation vetovoima kompensoituu.
Mitataan indusoituva jännite U, kun
kela liikkuu nopeudella v
magneettikentän läpi.
⇒ mgv = UI

19. MIKES-metrologia Heikki Isotalo
Wattivaaka kg 2/2

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NykyinenNykyinen ampeerinampeerin mmääääritelmritelmää

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U = R I

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SINIS-piiri A
J.P. Pekola, J.J. Vartiainen, M. Möttönen, O.-P. Saira, M. Meschke,
and D.V. Averin, Hybrid single-electron transistor as a source of
quantized electric current, Nature Physics 4 (2008) 120-124.

23. MIKES-metrologia Heikki Isotalo
Jännitteen mittanormaali V
• 1970-luvulle saakka
Weston kenno:
1955 1957 1960 1963 1966 1969 1972
0
1
2
3
4
-1
ΔV
( V)μ
CANADA
CANADA
• Nykyisin: Josephson
jännitenormaali:

24. MIKES-metrologia Heikki Isotalo
Josephson ilmiö V
• Josephson ilmiö nähdään, kun kaksi suprajohdetta
yhdistetään heikon linkin avulla.
tunnelointi mahdollista elektronipapreilla
• Jos jännite on V vallin yli, tunneloinnissa nähdään
energian syntyminen säteilynä hf = 2eV
V
hf
V = n(h/2e)f

25. MIKES-metrologia Heikki Isotalo
Resistanssin mittanormaali Ω
• 1980-luvulle saakka
käytettiin 1 Ω lankavastusta

26. MIKES-metrologia Heikki Isotalo
04/2013:
12.9 kΩ (i = 2) quantum Hall
plateau in graphene at 2 T
observed at MIKES
Kvantti Hall on nykyinen toteutustapa
Resistanssin mittanormaali Ω

27. MIKES-metrologia Heikki Isotalo
Kvanttimetrologiakolmio U=R I
• Onko luonnonvakioilla
samat arvot kaikissa
kolmessa ilmiössä?
• Toimiiko ohmin laki?
Quantum
Hall effect,
I = n(e2
/h)U
Josephson
effect,
V = n(h/2e)f
Single electron
effects,
I = nef
V
I f

28. MIKES-metrologia Heikki Isotalo

29. Kiitos !