lne watt balance - bipm · 21-22 nov. 2012 ccm workshop on the mise en pratique of the new...

Laboratoire national de métrologie et d’essais

LNE watt balance

G. Genevès

21-22 Nov. 2012 2CCM Workshop on the mise en pratique of the new definition of the kilogram

F. Bielsa1, Y. Briand1, J. David4, P. Espel1, T. Farah3, G. Genevès1, P. Juncar2, F. Koumondji1, A. Landragin3, S. Merlet3, P.A. Meury1, F. Pereira dos Santos3, P. Pinot2, Z.

Silvestri2, M. Thomas1

1LNE, 2LNE-LCM/Cnam, 3 LNE-SYRTE, 4 ENSAM


Experimental device

Tar

Beam

Magnetic circuit

Position sensor

Standard masssuspension

Coil suspension


Experimental device

Tar

Beam

Magnetic circuit

Interferometer (x3)

Position sensor (x3)

Position sensor

Coil suspension


Experimental device

Guiding stage

Motor

Mass exchanger


Experimental device

Guiding stage

Motor

Mass exchanger

Support

Magnetic circuitPositioning system


Experimental device


Static phase

I

Q.H.E

Lock-in

R.T.C

Voltmeter

ProgrammableCurrent source V

I

AC source

Agilent 3458Agilent 3458



Synchro


Dynamic phase

M

v

20 MHz

Agilent 3458

M

v

5 MHz

U

Agilent 3458

Translation stage



3458ou

3458Freq.

3458ADC

Synchro

Interferometers (x3)


Measurement sequence

t

Dyn. Phasen1 times

Static Phasen2 times

t1 t2 t3 t4 t5

…

Sequence repeated n times

+m/2 -m/2

i+ i-

V+ V-v+ v-


Dynamic measurements (one trajectory)

-1.0x10-2

-5.0x10-3

0.0

5.0x10-3

1.0x10-2

0.00 0.01 0.02 0.03 0.04-2x10-4

-10-4

010-4

2x10-4

3x10-4

δGe/

Ge

Coil z-axis position [m]

δU/U

, δv

/v, δ

Ge/G

e

(b)

(a)


Dynamic measurements(50 up-down trajectories)

0 . 0 0 0 . 0 1 0 . 0 2 0 . 0 3 0 . 0 4

5 3 6 . 2 2

5 3 6 . 2 4

5 3 6 . 2 6

5 3 6 . 2 8

5 3 6 . 3 0

5 3 6 . 3 2

BL

(T.m

)

C o i l z - a x i s p o s i t i o n [ m ]

4 x 1 0- 5

B L

0 . 0 0 0 . 0 1 0 . 0 2 0 . 0 3 0 . 0 4

- 3 x 1 0 - 3

- 2 x 1 0 - 3

- 1 x 1 0 - 3

0

1 x 1 0 - 3

2 x 1 0 - 3

3 x 1 0 - 3

δU/U

, δv/

v, δ

Ge/

Ge

C o i l z - a x i s p o s i t i o n ( m )


Measurements July-August 2012

-20

-15

-10

-5

0

5

10

15

20

24-juil 31-juil 07-août 14-août 21-août 28-août

date (2012)

106 .(

h-h

mea

n)/

hm

ean


Watt balance: next steps

European project kNOW: « Realisation of the awaited definitionof the kilogram » (INRIM, CNAM, EJPD, IOM, LNE, NMIJ, OBSPARIS, PTB)

� Measurements in air (1 ½ year)� 500 g, alignment, vibration reduction, velocity control, improving velocity

measurements, voltmeter calibration with JE, gravimeter with ultracold atoms,improvement of data processing algorithms, detailed uncertainty budget.

� Measurements in vacuum (1 ½ year)� 500g and 1kg, adaptation of the balance to 1 kg (force comparator,suspension

and coil support, current source), adaptation of the balance to vacuum use (glove box+load-lock), RT Josephson standard,…


Mise en pratiqueMass comparators:� Mettler Toledo Mone 6 positions + load lock and glove box

� Sartorius

Surface characterisation methods:� Thermal Desorption mass Spectroscopy� Mirage effect technique to measure adsorbability

� Optical roughness-metry and X-ray reflectometer

+33-17-28+59+250+250Susceptibilitémagnétique (χV 10

-6)

430

15200

Alliage Pt vitreux

60091616Azote-vide (ng/cm²)

27

97

175

21530

PtIr (1kg)

Etalon JM15

SiAu quaternaire

(5 x200 g)

Polissage LNE

Ir

(5 x 200 g)

Polissage LNE

PtIr

(8 x 125g)

Polissage BIPM

10001627Argon-vide (ng/cm²)

6806397Air- vide (ng/cm²)

1000250385175Dureté HV1

2330158502256021530Densité(kg/m3)


Mise en pratique: next steps

European project newKILO: « Developping a practical means of disseminatingthe new kilogram » (NPL, CEM, CMI, Cnam, DFM, LNE, EJPD, MIKES, PTB, SMU, TUBITAK UME, INRIM, NRC…)

� Defining and developping masses for the WB (Ir, Si,…500 g and 1 kg) and their traceability.

� Defining an ensemble of artifacts (ensemble-LNE) (PtIr, Ir, Si, Udimet, Alacrite, Stainless steel,…) kept in air or in inert gas.

� Study of new materials� Study of surface treatment techniques

� Study of air-vacuum/inert gas behaviour

� Study of transfer methods

� Evaluation of mass stability

lne watt balance - bipm · 21-22 nov. 2012 ccm workshop on the mise en pratique of the new...

Documents