Accuracy matters: Calibration Options for Lab Standards
Bob Stern
Principal Metrologist, Keysight
Technologies
Matthew Woerner
Metrologist, Keysight Technologies
Page
National Labs maintain SI Units
National Institutes of Metrology (NMI) . . .
NIST: National Institute of Science & Technology (USA)
NPL: National Physics Laboratory (UK)
NRC: National Research Council (Canada)
METAS: Swiss Federal Institute of Metrology
PTB: Physikalisch Technische Bundesanstalt (Germany)
CENAM: Mexican National Laboratory
INMETRO: Brazil National Laboratory
. . . are responsible for maintaining the most accurate
implementations of the key quantities needed to support
international commerce.
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Traceability
Traceability: Property of the result of a measurement or the value of
a standard whereby it can be related to the international system of
units (SI units) via national metrology institutes, through an
unbroken chain of comparisons all with stated uncertainties.
Source: International Vocabulary of Basic and General Terms in Metrology (VIM)
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Traceability to SI Units1
1. SI = Le Sisteme International d’unites (Int’l System of Units)
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram
1889 platinum-iridium
prototype kilogram
kept locked in Paris
BIPM safe.
US National standard
platinum-iridium
kilogram.
Metrology laboratory uses
reference masses to
characterize working
mass standards.
Your bathroom scale
Factory producing scales uses
a working standard mass
for scale calibration.
Traceability4
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Did you know?Gravity is local!
Location Acceleration in
m/s2
Acceleration in
ft/s2
Amsterdam 9.813 32.19
Athens 9.800 32.15
Auckland 9.799 32.15
Bangkok 9.783 32.1
Brussels 9.811 32.19
Buenos Aires 9.797 32.14
Chicago 9.803 32.16
Copenhagen 9.815 32.2
Frankfurt 9.810 32.19
Helsinki 9.819 32.21
Istanbul 9.808 32.18
Jakarta 9.781 32.09
Kuwait 9.793 32.13
Lisbon 9.801 32.16
London 9.812 32.19
Los Angeles 9.796 32.14
Mexico City 9.779 32.08
Montréal 9.789 32.12
New York City 9.802 32.16
Oslo 9.819 32.21
Ottawa 9.806 32.17
Paris 9.809 32.18
Rio de Janeiro 9.788 32.11
Rome 9.803 32.16
San Francisco 9.800 32.15
http://units.wikia.com/wiki/Gravity_of_Earth
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http://primarystandards.com/Home.aspx
El Segundo Center of Excellence
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Vacuum Measurements at El SegundoCustom vacuum chamber by Glenn Gaza
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Temperature
Thermodynamic temperature in Degrees Kelvin is an SI Unit
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Fixed Temperature Cell Primary StandardsHow do you calibrate PRTs and SPRTs?
COE Temp. Stds. Description
-195.5 ºC Boiling point, liquid Nitrogen
- 38.834 ºC Triple point, Mercury (Hg)
-0.01 ºC Triple point, water (H20)
231.928 ºC Freeze point, Tin (Sn)
419.527 ºC Freeze point, Zinc (Zn)
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Reference Thermometer (PRT)Fluke/Hart Scientific 5615-6 Platinum Resistance Thermometer
More good info on PRTs at: http://www.testequipmentdepot.com/fluke-calibration/pdfs/5616.pdf
PRT mfrgs : YSI Inc., Rosemount,
& Hart Scientific (now Fluke)
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SPRT report excerpt
This Standard Platinum Resistance Thermometer (SPRT) was calibrated with a DC Bridge at constant currents of 1.000 and 1.414 mA. The procedure followed is based on the technical information contained in NIST Technical Note 1265, “Guidelines for Realizing the International Temperature Scale of 1990 (ITS-90)”. In accordance with the ITS-90, the sub-ranges of 83.8058 to 273.16 and 273.15 K to 692.677, with the following fixed points and their uncertainties (k=2) were used to calibrate the thermometer.
FIXED POINT TEMPERATURE UNCERTAINTY
(point) (type) T90 (K) t90 (C) (mK, estimated)
LN2 Comp 77.6500 -195.5000 ±2.3
Hg TP 234.3156 -38.8344 ±1.4
H2O TP 273.1600 0.0100 ±0.4
Sn FP 505.0780 231.9280 ±2.5
Zn FP 692.6770 419.5270 ±2.8
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Thermocouple Cal report excerptMany physical cals have associated standard methods
The last sentence answers the question, “Why do we have to send thermocouples
in for calibration?”
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Optical Wavelength Standard
“Standard Reference Material (SRM) precisely absorbs light at 1531 nm
with an expanded uncertainty (coverage factor k=2) of ±0.0006 nm.
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NIST Water Bath
Courtesy of Ron Ginley, Section Head, RF Measurements, NIST, Boulder, CO
NIST Microwave Power Primary Standard
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Power Sensor Calibration Traceability Example
Calibration
Standard or
System
Cal factor
measurement
uncertainty:
TAT
(days)
NIST/NMI primary
standard - X
NIST/NMI CN mount- X
NIST/NMI thermistor cal
(such as 8487B)
0.57% @ 8 GHz
(see curve)
8 – 12 weeks
weeks
Roseville Standards Lab
(8487A-H84)
0.67% @ 8 GHz 15 days
Roseville Keysight cal +
uncertainty (8487A)
0.98% @ 8 GHz 7 days
http://www.nist.gov/calibrations/rf-microwave.cfm#611
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Power Sensor Cal Accuracy Choices (8481A)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8C
al
Facto
r M
ea
su
rem
en
t u
ncert
ain
ty (
%)
Frequency GHz
8481A Unc/Keysight cal
8481A-H84 Unc/Roseville
8478A Unc/ NPL
Keysight cal+ Unc.
7 days
H84 Stds Lab Cal
15 days
NMI CAL
8-12 weeks
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Traceability
Primary SI standard @ NMI 0
Lab Reference Standard 1
Stds. Lab Cal opt. “H84” 2
Keysight Cal + 3
Uncertainties
Normal use case 4
RF Power Measurement example
1
2
Primary Std.
Calorimeter 0
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keysight.com/find/StandardsLab
Keysight Standards Lab Capabilities
Attenuation
Color
Fiber Optic Power
Laser Power *
Luminous Intensity
Temperature
Wavelength
Electro-Optics
Antenna Gain
Attenuation
Frequency
Impedance
Impedance, Reflection
Coefficient
Linear Antenna Probe
On-Axis Polarization
Gain, Axial Ratio, Tilt Angle
Main Component Pattern
Amplitude, Phase
Noise Temperature,
Excess Noise Ration (ENR)
Phase Noise
Phase Shift Power
RF, Microwave,
Millimeter Wave
Angle
Flatness
Length
Magnification
Straightness/
Parallelism
Thread Lead
Dimensional
/Optical
Air Velocity
Density
Dew/Frost Point
Force
Gas Flow Rate
Helium Leak
Humidity
Mass
Pressure
Temperature
Torque
Vacuum
AC-DC Difference
AC Current
AC Voltage
Capacitance
DC Ratio
DC Resistance
DC Voltage
Inductance
Phase Angle
Ratio, AC Current
Ratio, AC Voltage
Sinusoidal/Shock
Sensitivity
Physical Electrical
Newly added Keysight capabilities
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Call to action
For any of the disciplines mentioned in
this Webcast . . .
. . . ask us if we can offer a Standards Lab
calibration for your reference Lab standards.
at what uncertainties?
. . . and turnaround time & cost.
www.Youtube.com/keysightcalrepair
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keysight.com/find/StandardsLab
Keysight Standards Lab Capabilities
Attenuation
Color
Fiber Optic Power
Laser Power *
Luminous Intensity
Temperature
Wavelength
Electro-Optics
Antenna Gain
Attenuation
Frequency
Impedance
Impedance, Reflection
Coefficient
Linear Antenna Probe
On-Axis Polarization
Gain, Axial Ratio, Tilt Angle
Main Component Pattern
Amplitude, Phase
Noise Temperature,
Excess Noise Ration (ENR)
Phase Noise
Phase Shift Power
RF, Microwave,
Millimeter Wave
Angle
Flatness
Length
Magnification
Straightness/
Parallelism
Thread Lead
Dimensional
/Optical
Air Velocity
Density
Dew/Frost Point
Force
Gas Flow Rate
Helium Leak
Humidity
Mass
Pressure
Temperature
Torque
Vacuum
AC-DC Difference
AC Current
AC Voltage
Capacitance
DC Ratio
DC Resistance
DC Voltage
Inductance
Phase Angle
Ratio, AC Current
Ratio, AC Voltage
Sinusoidal/Shock
Sensitivity
Physical Electrical
Newly added Keysight capabilities
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Technologies 2016
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