High-accuracy radiation thermometry at the
HighPhysikalisch--Technische Bundesanstalt (PTB)
Physikalisch
D. R. Taubert,
Taubert, K. Anhalt,
Anhalt, B. Gutschwager,
Gutschwager,
C. Monte, J. Hartmann, J. Hollandt
Physikalisch--Technische Bundesanstalt
Physikalisch
Filterradiometer
Physikalisch--Technische Bundesanstalt
Physikalisch
Overview
I t d ti
Introduction
Low-- / midLow
mid-temperature calibration facility
High--temperature calibration facility
High
High--temperature eutectic fixed
High
fixed--points
Summary
Physikalisch-Technische Bundesanstalt
2
Introduction
Temperature
governs most production processes in industry
crucial for optimized productivity and quality assurance
frequent measurement technique – radiation thermometry
annuall growth
th rate:
t more than
th 10%
600,000 radiation thermometers sold / year
15 000 th
15,000
thermography
h systems
t
sold
ld / year
market volume: > 1 billion €
Physikalisch-Technische Bundesanstalt
3
Introduction
Increased demand of calibrations in the field of
radiation thermometry
PTB operates two calibration facilities:
Low-/ midLowmid-temperature calibration facility;
temperature range: -60 °C to 962 °C
High temperature calibration facility;
temperature range: 900 °C to 3000 °C
Realization and dissemination of
p
radiation temperatures
Physikalisch-Technische Bundesanstalt
4
Low-- / mid
Low
mid--temperature calibration facility
schematic view
Sodium (Na)
Caesium (Cs)
Water (H2O)
Ammonia (NH3)
Heat-pipe
Heat-pipe
p p BB
p p BB
Heat-pipe
Heat-pipe
p p BB
p p BB
-60 °C to 50 °C 50 °C to 270 °C 270 °C to 650 °C 500 °C to 962 °C
ε = 0.9996
ε = 0.9996
ε = 0.9999
ε = 0.9998
SPRT
SPRT
SPRT
SPRT
y
x
Thermal camera or
radiation thermometer
on translation stage
3000 mm
600 mm
Physikalisch-Technische Bundesanstalt
5
Low-- / mid
Low
mid--temperature calibration facility
cross--section of sodium / cesium heat
cross
heat--pipe blackbody
thermocouple
or
Pt 100
bifilar
heating
water-cooled
housing
200
200mm
368 mm
ø 41 mm
ø 92 mm
SPRT
950 mm
heat-pipe
ceramic insulation
heater temporal stability: 0.1 K
heat--pipe temperature stability:
heat
10 mK
Physikalisch-Technische Bundesanstalt
6
Low-- / mid
Low
mid--temperature calibration facility
cross--section of H2O / NH3 heat
cross
heat--pipe blackbody
cooling element
housing
N2 purging
aperture
Ø 60 mm
525 mm
PRT
heat-pipe
heating elements
heater temporal stability: 0.1 K
heat--pipe temperature stability:
heat
10 mK
Physikalisch-Technische Bundesanstalt
7
Low-- / mid
Low
mid--temperature calibration facility
PTB heat
heat--pipe blackbodies
Blackbody
Temperature
range / °C
Cavity
diameter / mm
Cavity
Emissivity
NH3-BB
BB
-60
60 to 50
60
0 99990 ± 0.00006
0.99990
0 00006
H20-BB
50 to 270
60
0.99980 ± 0.00015
Cs-BB
270 to 650
41
0.99960 ± 0.00017
N BB
Na-BB
500
00 to 962
41
0 99960 ± 0.00017
0.99960
0 0001
Physikalisch-Technische Bundesanstalt
8
Low-- / mid
Low
mid--temperature calibration facility
z
y
x
Physikalisch-Technische Bundesanstalt
9
Low-- / mid
Low
mid--temperature calibration facility
radiation temperature standard uncertainties (k=
(k=1)
1)
Radiation
temperature / °C
Uncertainty of
radiation temperature / °C
1.6 µm
-60
0
50
100
200
300
400
600
800
960
0.035
0.035
0.035
0.08
0.1
0.02
0.03
0.06
0.08
3.9 µm
0.1
0.035
0.035
0.035
0.08
0.10
0.03
0.05
0.07
0.10
10 µm
0.035
0.035
0.035
0.035
0.08
0.10
0.05
0.08
0.11
0.14
Physikalisch-Technische Bundesanstalt
10
High temperature scale
Realization and dissemination of radiation temperature
scale above the AgAg-FP (961.78 °C):
Gold fixedfixed-point (Au(Au-FP) blackbody radiator: 1064.18 °C
High temperature blackbody (HTBB):
variable temperature, 900 °C to 3000 °C
High quality transfer standard radiation thermometers (LP3)
Tungsten strip lamps operated as radiation temperature
standards
Physikalisch-Technische Bundesanstalt
11
Gold fixedfixed-point blackbody
hit crucible
ibl
graphite
water cooled
housing
di
heat-pipe
h
i
sodium
argon
gas inlet
heating zone
fixed point
metal (Au)
alumina tube
insulation
heat--pipe based design
heat
cavity aperture diameter: 3 mm
ε = 0.99999
large fixedfixed-point material amount (~ 3 kg Au)
excellent performance
Physikalisch-Technische Bundesanstalt
12
Gold fixedfixed-point blackbody
dete
ector signa
al (normallized)
freezing plateau
1.007
1.006
1.005
1.004
1.003
100 mK
1.002
950
1000
1050
1100
time / min
freezing plateau duration: ~ 90 minutes
temperature stability: ~ 10 mK
but: limitation to one
temperature: 1337.33 K
Physikalisch-Technische Bundesanstalt
!
13
High Temperature Blackbody (HTBB 3200pg)
PTB primary standard
Radiation temperature
above
the
Ag
b
th AgA -FP
Spectral radiance
directly Joule
Joule--heated cavity
(DC, 700 A max.)
operating temperature range:
1000 K to 3200 K
temporal stability:
better than 250 mK
large aperture diameter : 20 mm
ε = 0.999
0 999 ± 0.001
0 001
Physikalisch-Technische Bundesanstalt
14
Linear pyrometer LP3
schematic view
thermostat
photodiode
T
f radiation
di ti
th
t for:
f
Transfer
thermometer
filter wheels
target field stop
International scale comparisons
Internal highhigh-temperature scale
dissemination
Main characteristics:
λeff = 650 nm (950 nm)
Temperature range:
800 °C to 2900 °C
adjusting telescope
aperture stop
FOV: 0.8 mm Ø at 690 mm
Good stability and linearity
Small SSE
c2
⎛
⎞
Iphoto (T ) = C ⋅ exp⎜ −
⎝ A ⋅T + B ⎠
Standard uncertainty:
0.3 °C at 800 °C
t
to
1.0 °C at 2900 °C
Physikalisch-Technische Bundesanstalt
15
High temperature scale – realization and dissemination
Radiation temperature
CALIBRATION ARTEFACT
COMPARISON / DISSEMINATION
Radiation temperature and spectral radiance
PRIMARY STANDARD
HIGH TEMPERATURE BLACKBODY
(HTBB, 1000 K to 3200 K)
T90 (ITS-90)
Temperature
T
t
T90
PRIMARY STANDARD
GOLD-FIXED-POINT
BLACKBODY (Au BB)
T (absolute filter radiometry)
Detector Φ
PRIMARY STANDARD
CRYOGENIC
RADIOMETER
Physikalisch-Technische Bundesanstalt
16
Spectral radiance comparator facility
HeNe
MCT
InSb
InAs
Si
InGaAs
Detector
translation unit
PMT
Step 1:
Determination
T90 (HTBB)
800 mm
PMT
1800 mm
Grating double
monochromator
0.25 m, additive mode
Linear
Pyrometer
(LP3)
Chopper/filter
wheel
Imaging mirror
f = 600 mm
F/#: 8..20
Ambient
Tungsten
temperature strip lamp
blackbody
Goldfixed-point
blackbody
(Au-BB)
1500 m
mm
Translation range:
3000 mm
alternative
Step
Step
1:2:
artefact
Determination
Tcalibration
(HTBB)
Calibrated
filter radiometer for
absolute thermometry
CCD camera
High
temperature
blackbody
(HTBB, 960 °C
to 3000 °C)
Physikalisch-Technische Bundesanstalt
17
Spectral Radiance Comparator Facility
Physikalisch-Technische Bundesanstalt
18
ITS--90 and high
ITS
high--temperature fixed points
Interpolation
Extrapolation
Interpolation
Pt- Widerstandsthermometer
resistance thermometer
0,01 °C
Zn
Al
Au Fe-C
Ag Cu Co-C
Pd-C
660,323 °C
1084,13
1153 °C
1492 °C
C
419 527 °C
419,527
C
961
961,78
78 °C
C
Pt-C
Ru-C
1738 °C
1953 °C
C
Ir-C
Re-C
TiC-C
ZrC-C
2290 °C
2761 °C
2474 °C
C
2883 °C
C
1.0
Uncetainty ITS-90 (k=2)
0.8
U/K
Ga
Sn
H2O In
Strahlungsthermometer
Radiation
thermometer
Radiation
thermometer
Uncertainty ITS-90 and
Radiation thermometer U=0.2%
U 0.2%
Additional f ixed points
0.6
0.4
0.2
0.0
1000
1500
2000
2500
3000
t90 / °C
Physikalisch-Technische Bundesanstalt
19
Eutectic fixedfixed-point blackbodies
C
Metal-CarbonMetalCarbon-Fixed points
in graphite crucibles
M
crucible material is part of the
fixed point material
no contamination through crucible
material
higher stability
better reproducibility
F C
Fe-C
Co-C
Pd-C
Pd C
1153 °C
1492 °C
Pt-C
Ru-C
R C
1738 °C
1953
19 3 °C
Ir-C
R
Re-C
C
TiC-C
Z
ZrC-C
CC
2290 °C
2761 °C
2474
24 4 °C
2883 °C
Physikalisch-Technische Bundesanstalt
20
Design / construction of eutectic fixedfixed-point blackbodies
Both fixedfixed-point cells
d i
designs
have:
h
the same outer diameter
the same length/diameter
g
ratio of the cavity
a calculated emissivity
0.9997
several layers of C/C sheet
insulation
3 mm Ø cavity:
radiation
thermometry
8 mm Ø cavity:
radiometry,
photometry
Anhalt et al. ((2008))
Large- and small- aperture fixed-point cells of Cu, Pt-C, and Re-C
International Journal of Thermophysics, 29(3), pp. 969 - 983.
Physikalisch-Technische Bundesanstalt
21
Eutectic fixedfixed-point cell relative comparison
BNM INM
BNM-INM
2 identical furnaces
NMIJ
0.4
Co-C
Pd-C
NPL
Pt-C
Ru-C
2 radiation
ad a o thermometer
e o e e LP3
3
15 fixed point cells
Re-C
0.3
(NMIJ, BNMBNM-INM, NPL
NPL))
NMIJ
0.1
NPL
0
Pt-C
-0.1
-0.2
0.2
1.50
INM
-0.3
NMIJ
NPL
INM
1.00
-0.4
1200
1400
1600
1800
2000
2200
2400
t / °C
reproducibility single cell:
0.50
2600
∆T / K
T - Tmean / K
02
0.2
< 50 mK
difference Tmelt Co-C, Pt-C, Re-C: ~ 200 mK
0.00
-0.50
-1.00
-1.50
difference Tmelt Pd-C, Ru-C:
~ 400 mK
0
50
100
150
200
250
300
t /s
Physikalisch-Technische Bundesanstalt
22
Measurement
uncertainty
k=2, 0.6 K – 1.2 K
2510
2790
2950
2450
2740
2850
0
Temp
perature / °C
Reproducibility
0.2 K – 0.5 K
t / °C
Thermodynamic temperature determination
Re-C
30
0
TiC-C
0
34
ZrC-C
2884
2478
2761
2477
2760
2476
2759
2475
2758
2474
2757
2473
2756
2878
2472
2755
2877
4
Hartmann, J., Anhalt, K., et al. (2005).
Thermodynamic temperature measurements off the melting curves off Re-C,
C
TiC-C and ZrC-C eutectic irradiance mode fixed point cells.
In D. Zvizdic (ed.). 9th Int. Symp. on Temp. and Thermal Measurements (pp. 189 - 194).
7
10
55
2883
2882
2881
2880
2879
5
9
13
3
7
11 15
time / min
Physikalisch-Technische Bundesanstalt
23
Thermodynamic temperature determination
• radiance comparison method
1. HTBB temperature ~ Tmelt
2. Measurement of thermodynamic temperature of HTBB with FR
Nagano S furnace
Tmelt
melt
c2
exp(
− 1)
(
,
)
Lλ s λ Tmelt
λTHTBB
=
Lλ s (λ , THTBB ) exp( c2 − 1)
λTmelt
HTBB 3200pg
T ~ Tmeltlt
FR
Physikalisch-Technische Bundesanstalt
24
Thermodynamic temperature determination
• radiance comparison method
1. HTBB temperature ~ Tmelt
2. Measurement of thermodynamic temperature of HTBB with FR
3. Spectral radiance measurement of the HTBB with the LP3
Nagano S furnace
Tmelt
melt
c2
exp(
− 1)
(
,
)
Lλ s λ Tmelt
λTHTBB
=
c
Lλ s (λ , THTBB ) exp(
exp( 2 − 1)
λTmelt
HTBB 3200pg
T ~ Tmeltlt
LP3
Physikalisch-Technische Bundesanstalt
25
Thermodynamic temperature determination
• radiance comparison method
1. HTBB temperature ~ Tmelt
2. Measurement of thermodynamic temperature of HTBB with FR
3. Spectral radiance measurement of the HTBB with the LP3
4. Spectral radiance measurement of the eutectic cell
in the Nagano furnace with the LP3
Nagano S furnace
Tmelt
melt
c2
exp(
− 1)
Lλ s (λ , Tmelt )
λTHTBB
=
c
Lλ s (λ , THTBB ) exp(
exp( 2 − 1)
λTmelt
HTBB 3200pg
T ~ Tmeltlt
LP3
Physikalisch-Technische Bundesanstalt
26
Thermodynamic temperature determination / relative comparison
0.5
T - T_averag
ge / K
04
0.4
C C
Co-C
Pd C
Pd-C
Pt
Pt-C
C
R C
Ru-C
Thermod
Thermod.
0.3
NMIJ
0.2
NPL
01
0.1
INM
0
Relative
-0.1
NMIJ
02
-0.2
NPL
-0.3
INM
-0.4
-0.5
1324 °C
1491 °C
1738 °C
1954 °C
Anhalt et al.
Thermodynamic temperature determinations of Co-C, Pd-C, Pt-C and Ru-C eutectic fixed-point cells
Metrologia, 43, 2006, pp. S78-S83
Physikalisch-Technische Bundesanstalt
27
Absolute temperature comparison NIST – PTB using NPL cells
0.75
T - T aver.(PTB,NISTT) / K
0.50
0.25
PTB 2004
0.00
NIST 2003
-0.25
0 25
-0.50
-0.75
1500
Co-C
1600
Pd-C
1700
1800
Pt-C
1900
2000
Ru-C
2100
2200
2300
T /K
Co-C
Pd-C
Pt-C
Ru-C
PTB
1597.16
1765.02
2011.67
2227.12
U, k
k=2
2
0.22
0.27
0.32
0.41
NIST
1597.43
1764.95
2011.21
2226.74
U, k
k=2
2
0.17
0.21
0.27
0.34
PTB NIST
PTB-NIST
-0.27
0.12
0.53
0.48
U(PTB/NIST), k
k=2
2
0.28
0.34
0.42
0.52
Physikalisch-Technische Bundesanstalt
28
Summary
PTB instrumentation and experimental techniques for the realization and
dissemination of the temperature scale with optical methods
Low-/ midLowmid-temperature calibration facility: -60 °C to 962 °C
High temperature calibration facility: 962 °C to 3000 °C
Standard uncertainty of the disseminated radiation temperature:
40 mK at - 60 °C
10 mK at the AuAu-FP (1064.18 °C)
1000 mK at 3000 °C
Achievable standard uncertainties for radiation thermometer calibrations:
60 mK at - 60 °C
30 mK at 400 °C
1000 mK at 3000 °C
PTB meets all industrial requirements in the range from -60 °C to 3000 °C
Physikalisch-Technische Bundesanstalt
29
Emissivity determination at the PTB
in the temperature range from 0 °C to 600 °C
C.
C Monte
Monte, M.
M Becker,
Becker B
B. Gutschwager
Gutschwager, E
E. Kosubek and J
J. Hollandt
Physikalisch--Technische Bundesanstalt
Physikalisch
Physikalisch--Technische Bundesanstalt
Physikalisch
Outline
Motivation for an accurate emissivity determination
Experimental setup for emissivity measurement in air
Uncertainty
New experimental setup for emissivity measurement under vacuum
Summary
Physikalisch-Technische Bundesanstalt
31
Motivation
λ ⋅ T 2 ∆ε
∆T ≈
⋅
c2
ε
3000 K @ 1 µm: ∆T = 30 K
300 K @ 10 µm: ∆T = 3 K
Physikalisch-Technische Bundesanstalt
32
Motivation
Variability of INCONEL 600 samples
Preparatory work for the spectral emissivity pilot study of CCTCCT-WG9
Identical sample preparation, two different sample manufacturers
16 % variation
different manufacturers
O l individual
Only
i di id l emissivity
i i it determination
d t
i ti
allows
ll
an accurate
t temperature
t
t
measurementt
Physikalisch-Technische Bundesanstalt
33
Spectral emissivity measurement in air - setup
Measurement principle:
Ratio of the spectral radiance of the sample / spectral radiance of the reference blackbody
Radiance of the detector / surrounding
Reflectivity of the sample
Physikalisch-Technische Bundesanstalt
34
Spectral emissivity measurement ranges (air)
Temperature range:
80 °C to 430 °C
Wavelength range:
4 µm to 40 µm (2500 cm-1 to 250 cm-1)
Direction of observation:
0° to 70°
70°
Size of measured area:
circular 10 mm diameter
circular,
Acceptance angle of the optics: +/
+/-- 3°, NA 0.05
Homogeneity (camera):
circular measurement area
area,
20 mm diameter
The directional total emissivity and the hemispherical emissivity
are calculated from the directional spectral emissivity
Physikalisch-Technische Bundesanstalt
35
Spectral emissivity measurement in air - example
wavelength / µm
re
elative deviation
directional spectral emissivity
homogeneity at 250 °C and 4 µm
angle
Measurementt area
M
for the directional
spectral emissivity
wavenumber / cm-1
High-emissivity coating at 250 °C
HighApplication: reference coating for radiation thermometry up to 800 °C
Physikalisch-Technische Bundesanstalt
36
Uncertainty
Emissivity
E i i it off a SiCSiC-sample
l att 150 °C
wavenumber / cm-1
standard uncertainty
standarrd uncertainty
y
directional spectral emis
ssivity
emissivity
+/- standard uncertainty
wavelength
g / µm
µ
Physikalisch-Technische Bundesanstalt
37
Emissivity measurement under vacuum - setup
radiation sources chamber
cooled beamline
FT-spectrometer
detector chamber
vacuum-IR-transfer-radiation thermometer (VIRST)
Physikalisch-Technische Bundesanstalt
38
Emissivity measurement under vacuum - setup
reference blackbodies:
VLTBB and VMTBB
b l
bolometer
FT--spectrometer
FT
sample
holder
off--axis ellipsoid
off
No atmospheric interference
No convection → accurate determination of the sample surface temperature
Temperature range:
0 °C to 600 °C
g range:
g
Wavelength
1µ
µm to 1600 µ
µm ((10000 cm-1 to 6 cm-1)
Physikalisch-Technische Bundesanstalt
39
Emissivity measurement under vacuum - setup
LN2- / water cooled
enclosure
h ti
heating
plate
sample
e > 0.98
rotation
stage
vacuum sample holder 0 °C to 600 °C
Physikalisch-Technische Bundesanstalt
40
Emissivity measurement under vacuum
VMTBB (150 °C to 430 °C)
VLTBB (-173 °C to 177 °C)
Measurement principle:
measurement of the sample against
two blackbodies at two different
temperatures
Advantage of the method:
sample holder
(0 °C to 600 °C)
the background radiation, the warm
components of the FTFT-spectrometer
and the spectral responsivity of the
detection system are cancelled
Physikalisch-Technische Bundesanstalt
41
Summary
Determination of the directional spectral emissivity in air in the
temperature range from 80 °C to 430 °C (4 µm to 40 µm)
Determination of the directional spectral emissivity under vacuum in the
temperature range from 0 °C to 600 °C (1µm to 1600 µm)
Determination of the total and hemispherical emissivity
St d d uncertainty
Standard
t i t for
f the
th emissivity
i i it 1% for
f samples
l with
ith an
emissivity > 0.3 and a sample temperature starting from 150 °C
Physikalisch-Technische Bundesanstalt
42
Muster
Physikalisch-Technische Bundesanstalt
43