uusi mittayksikköjärjestelmä klubiesitys 2013

Uusi mittayksikköjärjestelmä

Heikki IsotaloJohtaja

MIKES-metrologia Heikki Isotalo

"If you can't measure it - you can't improve it"

Lord William Thomson Kelvin


Mittatekniikan keskus (MIKES)

Henkilökunta 8Henkilökunta 60


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”


NykyinenNykyinen mittayksikkmittayksikkööjjäärjestelmrjestelmää


UusiUusi mittayksikkmittayksikkööjjäärjestelmrjestelmää


Uusi mittayksikköjärjestelmä


Conférence générale des poids et mesures

- 2011 – 2015 – 2019 -

55 États Membres du BIPM, et 37 Associés à la Conférence générale


10

Metri konventio

Finnish members:1953-1971 Yrjö Väisälä

1992-1998 Olli Lounasmaa

MIKES is member in CC for Length,

CC for Electricity andMagnetism, CC for Thermometry, andCC for Photo- and

Radiometry


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 parallelconductors 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.


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?


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


Uudet määritelmätsecond (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 srW−1, which is equal to lm W−1.


Kilon prototyyppi

• Pt (90%) / Ir (10%) sylinteri d ≈ h ≈ 39 mm säilytetäänBIPM: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


BIPM


Piipallo – kg 1/2

• Lasketaan atomien lukumäärä yksikiteisessä

piipallossa

• Käytetään 28Si (99,995%) ; isotooppisuhde

on suurin mittausepävarmuuden lähde

PTB Annual Report 2012


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


Wattivaaka kg 2/2


NykyinenNykyinen ampeerinampeerin mmääääritelmritelmää


U = R I


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.


Jännitteen mittanormaali V

• 1970-luvulle saakkaWeston kenno:

1955 1957 1960 1963 1966 1969 19720

1

2

3

4

-1

ΔV( V)μ

CANADA

CANADA

• Nykyisin: Josephson jännitenormaali:


Josephson ilmiö V

• Josephson ilmiö nähdään, kun kaksi suprajohdettayhdistetään heikon linkin avulla.

tunnelointi mahdollista elektronipapreilla

• Jos jännite on V vallin yli, tunneloinnissa nähdäänenergian syntyminen säteilynä hf = 2eV

V

hf

V = n(h/2e)f


Resistanssin mittanormaali Ω

• 1980-luvulle saakkakäytettiin 1 Ω lankavastusta


04/2013: 12.9 kΩ (i = 2) quantum Hall plateau in graphene at 2 Tobserved at MIKES

Kvantti Hall on nykyinen toteutustapa

Resistanssin mittanormaali Ω


Kvanttimetrologiakolmio U=R I

• Onko luonnonvakioilla samat arvot kaikissa kolmessa ilmiössä?

• Toimiiko ohmin laki?Quantum

Hall effect,I = n (e

2/h)U

Josephsoneffect,

V = n (h/2e)f

Single electroneffects,I = nef

V

I f

Kiitos !

uusi mittayksikköjärjestelmä klubiesitys 2013

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