NISTSPEtjALPUBLi^ .

Dimensional Measurements , . ,

^

j jvMECHANICMMEASU . ,

Optical: Radlation Measurements

. iQ^JiaNG RAP

' Electromagnetic Measurements

' Time And Frequency Measurement^ j-;-

FOR INFORMATION, PHONE (301) 975-2002

U.S. Der^tment Of Commerce National Institute Of Standards And Technology

NisT Calibration Services Users Guide 1991

Joe D. Simmons, Editor

Physical Measurement Services Program

National Institute of Standards and Technology

Gaithersburg, MD 20899

NIST Special Publication 250

Revised October 1991

(Supersedes 1989 Edition)

U.S. Department of Commerce

Robert A. Mosbacher, Secretary

Robert M. White, Undersecretary for Technology

National Institute of Standards and Technology

John W. Lyons, Director

FOR INFORMATION, PHONE (301) 975-2002
National Institute of Standards and Technology

Special Publication 250, 1991 Edition

Natl. Inst. Stand. Technol., Spec. Publ. 250, 1991 Ed.,

220 pages (Revised Oct. 1991)

CODEN: NSPUE2

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1991

For sale by the Superintendent of Documents,

U.S. Government Printing Office, Washington, DC 20402

U.S. Government Printing Office

Washington: 1991
Foreword

The NIST Calibration Services Users Guide provides detailed descriptions of the currently available NIST calibration services, special-test services, and measurement assur- ance programs. This document is a revised edition of NIST Special Publication 250. It describes the NIST services available as of the fourth quarter of 1990 and reflects a number of important changes since the 1989 edition was published. A detailed description is given of each measurement service, and a large number of NIST technical ex- perts are cited (who may be contacted for further information concerning services or measurement problems). Future editions will be published periodically as NIST ser- vices change.

This document also presents a detailed description of a number of Measurement

Assurance Program (MAP) services. These are carefully designed quality control pro- grams for critical measurements that allow the user to achieve a high level of confi- dence that the measurements being made in the user's laboratory are consistent with

national standards and adequate for intended use. MAP services are available for some basic measurement quantities (e.g., laser power and energy).

A Fee Schedule for the services described in this Users Guide is published annually.

It lists current prices for the services described here. NIST will notify users of changes

in services or proposed changes in services by means of announcements in the Fee

Schedule. In addition, information about upcoming NIST Measurement Seminars is announced there. It is important that you refer to the current issue of the Fee Schedule in order to have up-to-date information with respect to NIST contacts. A companion document to this guide is NIST Special Publication 260, NIST Stan- dard Reference Materials Catalog. This document describes over 1,100 Standard Ref- erence Materials (SRM's) certified by NIST for use in industrial quality control,

materials testing, environmental testing, and clinical testing applications. A copy of SP

260 may be obtained by calling (301) 975-6776.

The Physical Measurement Services Program welcomes suggestions on how this publication can be made more useful to those who rely on NIST physical measurement

services. Suggestions are also welcome concerning needs for new calibration services,

measurement assurance programs, or other measurement services.

Joe D. Simmons

Physical Measurement Services Program

iii
Abstract

The National Institute of Standards and Technology (NIST) Calibration Services Users

Guide provides detailed descriptions of currently available NIST calibration services,

measurement assurance programs, and special-test services. The following measure- ment areas are covered: (1) dimensional; (2) mechanical, including flow, acoustic, and

ultrasonic; (3) thermodynamic; (4) optical radiation; (5) ionizing radiation; and (6)

electromagnetic, including dc, ac, rf, and microwave. A separate Fee Schedule is issued

annually, providing current prices for the services offered, updates on points-of-contact, and information on measurement seminars.

Key words: calibration; measurement assurance; measurement services; standards;

traceability.

iv
Acknowledgments

Many NIST staff members contributed to the development and preparation of this guide. Over 50 members of the NIST technical staff contributed data and information

that have been incorporated into the guide. Special thanks should go to the SP 250

committee, which included Dan Flynn, John Mayo-Wells, Arthur McCoubrey, William

Ott, and Carolyn Stull. Joanne Marshall served as production manager and coordinated the preparation of the final document. Editorial assistance was provided by

Armatha Osborne, who did an excellent job in typing. Kathy Hillen, NIST Boulder,

arranged for the Boulder photographs and verifications. NIST Publications Production

staff made many valuable suggestions and typeset the final draft.

The Editor

V
List of Tables

Table Page

1. Estimated Systematic Uncertainties of Piston Gage Calibrations

in Gage Mode 55

2. Thermometer Calibration Uncertainties 61

3. NIST Two-Pressure Humidity Generator, Mark 2, Range

and Uncertainty 72

4. Primary Standard Measurement Capabilities 88

5. Measurement Capabilities 89

6. Low-Level MAP Transfer Standards 90

7. Pulsed CO2 Calibrations 91

8. Specifications for Calibration of Gamma-Ray Emitting Solutions

Which Are Submitted for Calibration 96

9. Specifications for Calibration of Gamma-Ray Solution Sources 97

10. Specifications for Calibritions Using the 2 ira Proportional Counter

and the 0.8 tra Defined Solid Angle Counter 97

11. Specifications for Special Tests of Beta-Particle-Emitting

Solution Sources 98

12. Irradiation Parameters for Fission Spectra and Maxwellian

Thermal Neutron Fields 101

13. X-Ray Beam-Quality Parameters 105

14. Calibration Uncertainties for DC Resistance Standards 115

15. AC-DC Difference Calibration Service 137

16. Specifications and Estimated Uncertainties for Low-Frequency

TVC Services 139

17. Specifications and Estimated Uncertainties for High-Frequency

TVC Services 139

18. Specifications and Estimated Uncertainties for Peak-to-Peak

Detector Services 140

19. Specifications and Estimated Uncertainties for RF Micropotentiometer

Calibrations 140

20. Specifications and Estimated Uncertainties for Data Converter

Calibrations 144

21. Available Values of the Parameters for Routine Wattmeter,

Watthour Varmeter and Varhour Testing 160

22. Summary of NIST Standard Field Strength Facilities 183

23. NIST Impulse Generator Spectrum Amplitude Measurement

Service Capabilities 185

24. Limits of Uncertainty for Calibration of Fast Repetitive Baseband

Pulse Parameters 185

vi
List of Figures

Figure Page

1. Accuracy of Length Measurements at NIST 15

2. Precision of Angle Calibrations for Master

Angle Gage Blocks and Polygons 22

3. Total Uncertainty for the NIST Airspeed

Measurements Capability 35

4. NIST Precision of Weighing for Mass Standards

Ranging from 10"* to 10"" Kilograms 38

5. Uncertainties of NIST Low Pressure and Vacuum Standards 58

6. Uncertainties for NIST Calibration of Temperature

Measuring Instruments 61

7. Uncertainties for NIST Spectral Radiance Calibrations 81

8. Uncertainties for NIST Spectral Irradiance Calibrations

of Type PEL Lamps 82

9. Uncertainties of NIST DC Voltage Measurements 128

10. Uncertainty for NIST Data Converter Test System

for Resolutions from 12-18 Bits 144

11. Estimated Total Uncertainties of the NIST Phase

Angle Calibration Standard 157

vii
Contents

Chapter 1 —

Policies

A. Introduction 1 B. Types of Services 1 C. Criteria for Quality Assurance 1 D. Fees 2

E. Reports of Test Results 2

F. Traceability 2

G. Reference to NIST Advertisements 2

H. Disclaimer 3

I. Questions and Inquiries 3

Chapter 2-

Ordering Instructions — Domestic Customers

A. Turnaround Time 5

B. Prearrangements and Scheduling 5

C. Purchase Order 5

D. Shipping, Insurance, and Risk of Lx)ss 6

Chapter 3-

Special Instructions — Foreign Customers

A. Criteria for Providing Service 9

B. Special Instructions 9

C. Foreign Inquiries 10

Chapter 4-

Dimensional Measurements

A. Length Measurements 13

lOOlOC Gage Blocks

10020C Line Standards

10030C Surveying and Oil Gaging Tapes

10040S Special Tests of Surveying Leveling Rods

10050S Special Tests of Length Standards

10060S Special Tests of Sieves

B. Diameter Measurements 17

IIOIOS Special Tests for Plug Gages: External

Diameter Standards

11020C Measuring Wires for Threads and Gears

11030S Special Tests for Spherical Diameter Standards: Balls 11040S Special Tests for Internal Diameter Standards:

Ring Gages

11050S Special Tests of Length and Diameter

11060S Special Tests of Step Gages

11070S Special Diameter Measurement, by Prearrangement

viii
C. Complex Dimensional Standards 19 12010C API Threaded Plug and Ring Gages

12020S Special Tests of Threaded Plug and Ring Gages

12030S Special Tests of Two-Dimensional Gages

12040S Special Complex Dimensional Tests, by Prearrangement

D. Optical Reference Planes & Roundness Standards 21 13010S Special Tests of Optical Reference Planes (Flats)

13020S Special Tests of Roundness

13030S Special Tests of Roundness Calibration Specimens

E. Angular Measurements 22

14010C Angle Gage Blocks

14020S Special Tests of Optical Polygons

14030S Special Tests of Rotary and Indexing Tables

14040S Special Tests of Wedges

14050S Special Angular Measurements, by Prearrangement

F. Laser Measurements 24

14510S Laser FrequencyAVavelength

G. Surface Texture 25

15010C Roughness Calibration Specimens

15020C Surface Roughness Comparison Specimens

15030C Step Height Measurements

H. Hydrometers 27

16010C Reference Standard Hydrometers

I. Volume and Density 28

17010C Volume Standards

17020S Special Tests of Volume Standards

17040S Special Tests of Density: Liquids

Chapter 5-

Mechanical Measurements

A. Flow Rate Measurements 31

18010C Single Turbine Meters

18020C Tandem Turbine Meters

18030C Flow Rate Meters (Direct Reading in Flow

Rate Units)

18040C Head Class Flow Measurement Devices

18050S Special Tests for Liquid and Gas Flow Rates

B. Flow Measurements at Cryogenic Temperatures 34

18800S Special Tests of Cryogenic Liquid Flow

ix
C. Airspeed Measurements 35

19010C Pitot-Static Tubes 1.3 to 67 m/s (3 to 150 mph)

19020C Low Airspeed Instruments

07.6 to 10.2 m/s (15 to 2,000 fpm)

19030S Meteorlogical Airspeed Instrumentation

1.3 to 67 m/s (3 to 150 mph)

19040S Special Tests of Airspeed Instruments

D. Mass Standards 37

22010C-22030C . . .Single Weight Sets (1 mg to 30 kg)

22040C-22110C . . .Single Weights (1 mg to 30,000 kg)

22130C-22150C . . .Single Weights for Deadweight Pressure Testers 22170S Special Mass Measurement Services

22180M Measurement Assurance Program for Mass

E. Force Measurements 41

23010C-23240C. . .Fo'ce Transducers (to 1,000,000 Ibf, 1 or 2 Modes)

23250C Force Transducers (over 1,000,000 IbQ

23260S Special Tests of Force Transducer

F. Vibration Measurements 43

24010C-24030C. . .Vibrations (Pickup Sensitivity, 2 to 10,000 Hz)

24040S Special Shock Measurement Services

24050S Special Tests of Pickup Sensitivity

24060S Special Vibration Tests

G. Acoustic Measurements 45

25010C-25020C. . .Pressure Response: WE Type 640AA

Microphones or Equivalent

25030C-25040C. . .Pressure Response: Tokyo Riko Type ECL

MR 112, or Equivalent Half-Inch Microphones

25050C Free-Field Response: Tokyo Riko Type ECL

MR 112, B&K Types 4133, 4134, 4165, 4166, or 4180

Equivalent Half-Inch Microphone

25060S Special Tests of Acoustic Devices

25070S Special Tests of Earphones

H. Ultrasonic Reference Block Measurements 48

26030S,26050S,26070S. . . Special Tests of Aluminum Reference Blocks

26040S,26060S,26070S. . . Special Tests of Titanium or Steel Reference

Blocks

26080S Special Tests of Velocity Reference Blocks

I. Ultrasonic Transducer Measurements 50

26100C Ultrasonic Transducer Power Output; Radiation

Pressure 26110C Ultrasonic System Power Output; Calorimeter

26120S Special Tests of Ultrasonic Transducers

X
J. Acoustic Emission Transducer Measurements 52

226200C Acoustic Emission Transducer Amplitude and Phase

Sensitivity versus Frequency

26210S Special Tests of Acoustic Emission Transducers and

Sensors

Chapter 6-

Thermodynamic Quantities

A. Pressure Measurements 55

29010C Deadweight Piston Gages

29020C Controlled Clearance Piston Gages

29030C Pressure Gages and Transducers

29035C Mercurial Barometers and Manometers

29040S Special Tests of Pressure Gages

B. Low Pressure, Vacuum, and Leak Measurements 57

30010C-30011C. . .Absolute Low-Pressure Transducers

30020C-30021C. . .Differential Low-Pressure Transducers

30025C Ball-Type Deadweight Tester 30029C-30031C. . .Molecular Drag Gages

30034C-30038C. . .Ionization Gages

30040S Special Tests of Low-Pressure Gages

30050S Special Tests of Vacuum Gages

30060S Special Tests of Leak Artifacts

C. Laboratory Thermometers 60

31010C-31060C. . .Laboratory Thermometers

31070C Calorimetric Thermometers

31080C Beckmann Thermometers

31100C Quantity Tests of Liquid-in-Glass Thermometers

31110S-31160S . . .Special Tests of Thermometers

31260S Special Thermometry Services, by Prearrangement

D. Thermocouples, Thermocouple Materials, and Pyrometer 62

Indicators

32010C-32044C. . .Type S, R, B, E, J, K, N, and T, Measured with

Standard Thermocouples Covering 0-1750 °C

32070C Thermocouple Materials Tests against Pt Thermoelectric Standard with PRT (-100 to 300 °C)

32090C Type S Measured with Freezing-Point Standards

(0-1450°C)

32100C Pyrometer Indicators (Portable Potentiometers,

First Dial or Range)

32110C-32147C. . .Thermocouple Materials Tested against PT

Standard with PRT-Varian Temperature

Ranges

32150S Special Tests of Thermocouples and Thermocouple

Materials

xi
E. Resistance Thermometry 65

33010C-33130C. . .Capsule Platinum Resistance Thermometers

33410C Germanium and Rhodium-Iron Resistance

Thermometers

33150C-33310C. . .Long Stem Platinum Resistance Thermometers

33350S Special Tests of Resistance Thermometers

33360S Special Tests of Thermometric Fixed-Point

Devices

33370M-33390M . .Measurement Assurance Program for Temperature

F. Radiation Thermometry 69

35010C-35040C. . .Optical Pyrometers

35050C-35060C. . .Ribbon Filament Lamps (800 to 2300 °C)

35070S Special Tests of Radiation Pyrometers

G. Humidity Measureme its 71

36010C-36020C. . .Dew-Point Hygrometers

36030C Electric Hygrometers

36040C Electrolytic Hygrometers

36050C Aspirated Hygrometers

36060C Pneumatic Bridge Hygrometers

36070S Special Tests of Humidity

H. Total Heat Flux Gauges 73

36510S Special Tests of Total Heat Flux Gauges

Chapter 7 —

Optical Radiation Measurements

A. Photometric Measurements 75

37015C Luminous Intensity Rental Program

37025C Luminous Intensity-Submitted Lamp

37035C Color Temperature Determination on Lamp

Submitted for 37025C

37080S Special Tests for Luminous Flux of

Incandescent Lamps

37140C Airway Beacon Lamps

37170C Opal Glass Luminous Directional

Transmittance Standards

37180S Special Photometric Tests

B. Spectrophotometric Measurements 77

38010C-38040C. . .Spectral Transmittance Filters 38050C Wavelength Standards (Holmium Oxide Glass)

38060S Special Tests of Spectral Transmittance and

Reflectance

38070M-38074M . .Measurement Assurance Program for Retroreflectance

38080M Measurement Assurance Program for Transmittance

xii
38090S

38100S

Special Tests of X-Ray Photographic Step Tablets

Special Tests of Microcopy Resolution Test Charts

C. Radiometric Measurements 81 39010C-39030C. . .Spectral Radiance Ribbon Filament Lamps

39040C-39045C. . .Spectral Irradiance Quartz-Halogen Lamps

(250-2400 nm)

39050C Spectral Irradiance Deuterium Lamps

(200-350 nm)

39060S Special Tests of Radiometric Sources

39070C Photodiode Spectral Response Rental Package

39080S Special Tests of Radiometric Detectors

D. Radiometric Standards in the Far Ultraviolet 84

D.l Standard Sources 40010C Spectral Irradiance Standard, Argon Mini-Arc

40020C Spectral Radiance Standard, Argon Mini-Arc

40030C Spectral Irradiance Standard, Deuterium Arc

Lamp

40040S Special Tests of Radiometric Devices in the

Near and Vacuum Ultraviolet

D.2 Standard Detectors in the Far Ultraviolet 86

40510C-40561C. . .Detector Standard, Windowless Photodiode

40599S Special Tests on Detectors from the Near

Ultraviolet to the Soft X-Ray Region

E. Laser Power and Energy 88

42110C-42111C. . .Laser Power and Energy Meter Calibrations

42120M Laser Power and Energy Measurement

Assurance Program

42130C-42131C. . .Optical Fiber Power Meter Calibrations

42140M Optical Fiber Power Meter Measurement

Assurance Program

42150M Low-Level Laser Measurement Assurance

Program

42160C Pulsed 10.6-|a,m Laser Calibrations

42170S Special Tests for Laser Power and Energy

Meters

42180S Special Tests for Optical Fiber Power Meters

Chapter 8-

lonizing Radiation l\/ieasurements

A. Radioactivity Sources 95

43010C-43020C. . .Gamma-Ray-Emitting Radionuclides in Solution

43030C-43050C. . .Alpha-Particle-Emitting Solid Sources

43060S-43070S . . .Special Tests of Beta-Particle-Emitting

Solution Sources

43090S Special Tests of Alpha-Particle-Emitting

Solid Sources

xiii
B. Neutron Sources and Neutron Dosimetry 100

44010C^4020C. . .Radioactive Neutron Sources

44060C Personnel Protection Instrumentation,

Californium Source Bare and Moderated

44070C Activation Detector Dosimetry, Thermal Neutrons

44080C Activation Detector Dosimetry, Californium

Fission Neutrons

44090C Activation Detector Dosimetry, ^^U Cavity

Fission Source

44100S Special Tests of Neutron Sources and Dosimeters

C. Dosimetry of X Rays, Gamma Rays, and Electrons 103

CO Special Instructions for Using Electron and Photon Dosimetry

Calibration and Test Services CI X-Ray and Gamma-Ray Measuring Instruments 46010C-46011C. . .Radiation Detectors - Calibration/Correction Factor 46020C^6021C. . .Pas.iive Dosimeters

46030S Special Tests of High-Gain Electrometers —

Charge Sensitivity

46040S Special Tests of X-Ray Penetrameters,

Ardran-Crookes Type

46050S Special Tests of X-Ray and Gamma-Ray

Measuring Instruments

C.2 Gamma-Ray Sources, Beta-Particle Sources, and Measuring Instruments 107

47010C-47011C. . . Gamma-Ray Sources

47030C^7035C. . . Beta-Particle Sources

47036C Ionization Chambers

47040S Special Tests of Gamma-Ray and Beta-Particle

Sources

C.3 Dosimetry of High-Energy Electron Beams 108

48010M-48011M. .Irradiation of Ferrous-Ferric Dosimeters

48020S Special Tests of Electron-Beam Dosimeters

D. Dosimetry for High-Dose Applications 110

49010C Calibration Irradiations of Customer-Supplied

Dosimeters Irradiated with '^Co Gamma Rays

49020C-49030C. . .Dose Interpretation of NIST Transfer

Dosimeters Irradiated by Customer

49040S^9041S . . .Special Tests of Dosimeters By Reading

with Spectrophotometer

49050S Special Measurement Services for Dosimeter

Response and Dose Distributions

Chapter 9-

Electromagnetic Measurements

A. Resistance Measurements 113

A.l DC Resistance Standards and Measurements

51100S Special Resistance Measurement Services, by

Prearrangement

xiv
51110M Measurement Assurance Program Services for Resistance

51130C Standard Resistor, Thomas-Type, 1 fl 51131C Standard Resistor, Evanohm Wirewound

High Precision, 10 kfl 51132C-51138C. . .Standard Resistor, Four-Terminal, 0.001-100 fi 51139C-51154C. . .Standard Resistor, 1 kH-l TH

51160C-51163C. . .Standard Resistor, for Current

Measurements (Shunts)

A.2 High-Voltage Standard Resistors 117

51210C High-Voltage Standard Resistors

A.3 High-Frequency Standard Resistors 118

51310S High-Frequency Standard Resistors, Two-Terminal

A. 4 AC Resistors 51410S Special Tests of AC Resistors, by Prearrangement 119

B. Impedance Measurements (Except Resistors) 120

B. 1 Low-Frequency Capacitance and Inductance Measurements

and Standards

52110S Special LF Impedance Measurements, by

Prearrangement

52130C-52131C. . . Standard Fixed, Fused-Silica, Dielectric Capacitor

52140C-52141C. . .Fixed Three-Terminal, High-Precision

Standard Capacitor with Coaxial Connectors

52150C Physical Tests to Qualify Three-Terminal

Air Capacitors for Measurement

52160C-52161C. . .Fixed Three-Terminal Standard Capacitor

with Coaxial Connectors

52170C-52171C. . .Two- or Three-Terminal Solid Dielectric

Standard Capacitor

52180C-52181C. . .Fixed Inductor, Self or Mutual

B.2 High-Frequency Standard Capacitors and Inductors 124

52210S-52211C . . .Two-Terminal, Low-Loss, Standard Capacitors

52220S-52221C . . .Three-Terminal, Low-Loss, Standard Capacitors

52310S Two-Terminal, High-0 Standard Inductors

B.3 Power-Frequency Capacitors 126

52400C Power-Frequency Capacitors

B.4 Q-Standards 127

52710C-52711C. . .Inductive Q-Standards

C. Voltage Measurements

C.l DC Vohage Measurements and Standards 128

53110S Special DC Voltage Measurements, by

Prearrangement

53120M .Measurement Assurance Program for DC

Voltage

53130C-53131C. . .Saturated Standard Cells 53140C Platinum Resistance Thermometer Temperature

Determination for Standard Cell Calibration

XV
53150C Unsaturated Standard Cells 53160C-53161C. . .Tests of Solid-State Voltage Reference

Standard

53180S-53190S . . .Special Handling

C.2 AC Voltage Measurements 133

53200S Special Tests of High-Accuracy Digital

Multimeters, Multifunction Calibrators, by

Prearrangement

53201S Special Tests of Low-Voltage AC-DC Transfer

Standards, by Prearrangement

C.3 AC-DC Thermal Voltage and Current Converters (to 1 MHz) 135

53310S Special AC-DC Measurement Services, by

Prearrangement

53340C-53341C. . .AC-DC Thermal Voltage and Current Converters

C.4 RF-DC Thermal Voltage and Current Converters (100 Hz-1 GHz) 138

53405S Spe cial Tests of AC Thermal

Voltage Converters, by Prearrangement

53410C-53415C. . .Lxjw-Frequency TVC Calibrations

53420C-53421C. . .High-Frequency TVC Calibrations

53430S-53431S . . .Peak-to-Peak Detector Calibrations

53440S Special Tests of RF Micropotentiometers,

by Prearrangement

53441C RF Micropotentiometer Calibration

53445S Special Calibration of RF Micropotentiometer

C.5 Data Converters 142

53500S Special Data Converter Services, by

Prearrangement

53510C A/D or D/A Converters, Linearity Errors,

10-Bit Correction Coefficients, and

Superposition Errors 53520C A/D or D/A Converters, Differential

Linearity Errors 53530C A/D Converter, Equivalent RMS Input Noise

53540S A/D or D/A Converters, Offset and Gain

Errors Relative to Legal Volt

D. Precision Ratio Measurements

D.l Inductive Dividers 146

541 lOS Special Ratio Measurements and Tests of

Inductive Voltage Dividers, by

Prearrangement

54120C-54131C. . .Inductive Voltage Dividers

D.2 Resistive Dividers 148

54210C Resistor and Resistive Dividers, Total

Resistance or Voltage Ratio

54211S Special Tests of Resistor and Resistive

Dividers at Direct Voltage Levels, by

Prearrangement

xvi
54212C Resistor and Resistive Dividers at 60 Hz,

Voltage Ratio and Phase Angle

54213S-54214S. . .Special Tests of Resistor and Resistive

Dividers

D.3 Capacitive Dividers 151

54310S-54311S . . .Special Tests of Capacitive Dividers

D.4 Mixed Dividers 152

54410S Pulse Voltage Measuring Systems, Including

Kerr Cells D. 5 Voltage and Current Transformers 153

54510C-54513C. . .Voltage Transformers, Ratio and Phase Angle

54520C-54522C. . .Current Transformers, Ratio and Phase Angle

54600S Special Tests of Dividers and Transformers,

by Prearrangement

E. Phase Measurements and Air Navigation Aids 156

E.l Phase Meters and Standards

55110S Special Tests of Phase Standards and

Related Instruments, by Prearrangement

55120C-55141C. . .Phase Meters

E.l Very-High-Frequency Omnidirectional Range (VOR) Measurements 158

55210C-55211C. . .VOR Bearing-Angle Indicators

55220C-55221C. . .VOR Generators

55230S Special VOR Tests

F. Power and Energy Measurements, Low Frequency 160

561 lOS Special Tests of AC-DC Wattmeters, by

Prearrangement

56200C-56202C. . .Watt, Watthour, Var, or Varhour Meter at 60 Hz

56210M Measurement Assurance Program for Watthour Meters

G. Microwave Measurements 163

G.l Bolometer Units, RF and Microwave

61110S-61129S Coaxial Thermistor Mounts, Combinations of

Calibration Factor, Effective Efficiency

Factor, and Reflection Coefficient

at Specified Frequencies in Range

0.1 MHz to 26 GHz

61144S-61155S Rectangular-Waveguide Power Meters,

Combinations of Effective Efficiency,

Efficiency Factor and Reflection

Coefficient within Specified Frequency

Bands Covering 8.2-96 GHz

61190S Special Microwave and RF Power Measurement

Services, by Prearrangement

G.2 Attenuators, RF and Microwave 167

61210S Coaxial Fixed and Variable Attenuators,

10 MHz to 26 GHz

xvii
6121 IC Coaxial Fixed and Variable Attenuators,

Measured at 30 MHz

61215C Waveguide Circular (Below Cutoff) (Piston)

Attenuator, Coaxial Connector, Measured

at 30 MHz

61230S Rectangular Waveguide Fixed and Variable

Attenuators, WR10-WR42 Waveguide Bands

61240S Special Attenuation Measurements of ThreePort and Two-Port Devices at 1.25 MHz

61250S Special Attenuation Measurements, by

Prearrangement

G.3 Coaxial and Waveguide Terminations, Reflection Coefficients 170

61310S Complex Reflection Coefficient of

Coaxial Terminations, 10 to 26 GHz

61320S Complex Reflection Coefficient of

Rectangular Waveguide Terminations

with Standard Flange Connectors at Frequencies

within WR10-WR42 Waveguide Bands

61340S Special Reflection Coefficient Measurements,

by Prearrangement

G.4 Phase Shifters, RF and Microwave 172

61410S Coaxial Fixed and Variable Phase Shifters; Characteristic Phase Shift Difference;

Precision Connectors; Measured at 30 MHz,

Range 0-360°

6141 IS Coaxial Fixed and Variable Phase Shifters; Phase Shift Difference; Precision Connectors;

1-26 GHz, Range 0-360°

61420S Variable Rectangular Waveguide Phase

Shifters; Phase Shift Difference at Frequencies WR10-WR42 Waveguide

Bands, Range 0-720°

61450S Special Tests of Phase Shifters, by

Prearrangement

G.5 Dimensional Verification of Coaxial Air Line Standards 174

61510S Coaxial Air Lines

G.6 Dielectric Material Measurements 175

61620S Special Tests for Dielectric Materials, 0.05 to 18 GHz

H. Noise Temperature Measurements 176

62020S Special Noise Temperature Measurements

(Electromagnetic), by Prearrangement

62100S-62111S. . . . Noise Temperature of Coaxial Noise

Sources, Type N Precision or 14-mm

Connectors

62112S-62113S. . . .Noise Temperature of Coaxial Noise Source,

APC 3.5 Connector

xviii
62115S-62116S. . . .Special Service for Waveguide Noise Sources

at Frequencies within WR90-WR284 Waveguide

Bands

62120S-62121S Noise Temperature of Rectangular Waveguide

Noise Sources at Specified Frequencies

in WR62 and WR90 Waveguide Bands

62130S-62131S. . . .Noise Temperature of WRIO Noise Sources

62132S-62133S Noise Temperature of WR15 Noise Sources

I. Electromagnetic Field Strength and Antenna Measurements 179

I.l Microwave Antenna Parameter Measurements

63100S Gain and Polarization of Standard Antennas

Using Extrapolation Range

63200S Measurement of Pattern, Gain, and Polarization

of Arbitrary Antennas Using Near-Field

Scanning Techniques

63300S Special-Test Service for Calibration of Probes

Used with Near-Field Scanning Techniques

63400S Special Consulting, Advisory, and Other

Services

1.2 Field Strength Parameter Measurements 182

64100S Special-Test Service for Antennas/Field

Strength Measurements, Utilizing Transverse Electromagnetic Cell Method

64200S Special-Test Service for Antennas/Field

Strength Measurements, Utilizing the Open

Field Method

64300S Special-Test Service for Antennas/Field

Strength/Reflectivity Measurements,

Utilizing the Anechoic-Chamber Method

J. Pulse Waveform Measurements 184

65100S Impulse Generator Spectrum Amplitude

(50 Ohm)

65200S Fast Repetitive Broadband Pulse Parameters

(50 Ohm)

65300S-65301S. . . .Network Impulse Response of Coaxial

Networks, 10 MHz to 10.0 GHz

65400S Pulse Time Delay through Coaxial

Transmission Lines

Chapter 10-

Time and Frequency Measurements

A. Time and Frequency Dissemination 189

76100S Special Frequency Measurement Service

761 lOS Special Global Time Service

xix
B. Oscillator Characterization 191

77100C Precision Oscillator Frequency Calibration

77110C Characterization of Atomic Time and

Frequency Standards

77120C-77131C. . .Characterization of Precision Oscillators: Time and Frequency Domain

77140S Special Time/Frequency Measurements

XX

Chapter

A

B

C

Introduction

Types of Services

Criteria for Quality Assurance D Fees E Reports of Test Results p Traceability

G References to NIST in Advertisements

H Disclaimer

f Questions and Inquiries
Policies

Introduction

The physical measurement services of

the National Institute of Standards

and Technology (NIST) are designed

to help the makers and users of precision instruments achieve the highest

possible levels of measurement quality and productivity. The hundreds of

individual services you will find listed and described in this Users Guide

constitute the highest order calibra- tion services available in the United

States. They directly link a customer's

precision equipment or transfer stan- dards to national measurement stan- dards. These services are offered to public and private organizations and

individuals alike.

Types of Services

You will find three types of physical

measurement services described in

this guide: Calibration Services, Special Tests, and Measurement Assur- ance Programs.

Calibrations and Special Tests generally designate those NIST services that check, adjust, or characterize

particular instruments, devices, and

sets of standards on a one-time-perrequest basis. The customer, in most

cases, ships an item requiring calibra- tion to the appropriate NIST laboratory in Gaithersburg, Maryland, or Boulder, Colorado, as noted in this Users Guide and in the separate Fee

Schedule. The calibrated item is shipped back to the customer, fol- lowed, under separate cover, by a re- port of test procedures and results. Measurement Assurance Programs,

or MAPs, are quality control pro- grams for calibrating a customer's entire measurement system. In a typical

MAP, a stable artifact or set of arti- facts—called transfer standards — are

first measured by NIST and sent to a customer's laboratory for a series of

measurements. The transfer standards

are then returned to NIST for

remeasurement, along with the participating laboratory's results. NIST re- ports its comparative findings to the

customer and, when necessary, offers guidance on how to achieve and

maintain measurement quality.

Successful use of a NIST MAP re- quires that the customer make periodic measurements of in-house check

standards to estimate the random er- ror and to ensure that the measure- ment process remains in a state of

statistical control. Unless a laboratory

has a measurement quality control

program to monitor continuously its own measurement process parameters, there is little point in participating in a MAP.

PLEASE NOTE: NIST does not

audit, regulate, or accredit metrology

laboratories as part of the MAP services. Whatever steps a participating

laboratory may take to improve its measurement process are undertaken

voluntarily.

C Criteria for Quality

M Assurance

All the measurement services described in this guide meet rigorous

criteria for quality assurance. Calibration Services and MAPs satisfy the

most demanding and explicit requirements in that these services are car- ried out regularly under preestablished and well-defined conditions; the measurement processes

involved are well-characterized, stable, and statistically controlled; and

quality-control procedures are well- defined and strictly followed. Further- more, each Calibration Service or MAP is planned and documented to permit continuity of service over time.

A Special Test is so designated for one or more of the following reasons:

1) the specific type of calibration is seldom requested, thus precluding the

maintenance of a large statistical base

for controlling the measurement process, 2) the test requested is unique,

or 3) the service is still under

1
development — meaning the measure- ment or calibration methods are still being perfected or all the quality-control documentation has yet to be completed.

Fees

NIST recovers the cost of providing

calibration services by charging a fee

for each calibration performed.

These fees range from a low of less than $150 for calibration of a laboratory thermometer to $50,000 or more

for special tests of large microwave

antenna systems.

The costs of services are not stated

in the Users Guide. Instead, they are

listed in a separate Fee Schedule,

which is updated and published, ef- fective January 1 annually to reflect changes in prices and services. Even

so, many services are performed at cost and you must provide the technical contact with an exact description of work before receiving a price

quote. Request a free copy of the current Fee Schedule by writing or

calling the Physical Measurement

Services Program (see section I).

Reports of Test Results

Reports on calibrations or other

services are regarded as the property

of the customer. Copies are not supplied to other parties except as re- quired by federal law or requested in writing by the customer. The results of calibrations and tests performed

by NIST apply only to a particular in- strument or standard at the time of

test unless otherwise clearly stated.

Traceability

Many Federal regulations and contracts require regulated organizations or contractees to verify that the measurements they make are "traceable"

and to support the claim of traceability by auditing records for equipment

used in the calibration process. This

regulatory requirement implies the

ability to relate individual measure- ment results through an unbroken

chain of calibrations to a common

source, usually U.S. national stan- dards as maintained by NIST, or

intrinsic standards based on fundamental constants of nature with

values assigned or accepted by NIST.

To adequately establish an audit trail for traceability, a proper calibration

result should include: the assigned

value, a stated uncertainty, identifica- tion of the standard used in the cali- bration, and the specification of any

environmental conditions of the cali- bration where correction factors should be applied if the standard or equipment were to be used under dif- ferent environmental conditions.

NIST is supportive of the practice

of making the user aware of traceability and providing the user details as to how traceability was established;

however, at the same time NIST cannot

condone the prominent display of its name on proprietary products or in the advertising of them. (See Sec. G).

NIST does not define nor enforce

traceability. Moreover, NIST is not

legally required to comply with traceability requirements of other federal

agencies; nor do we determine what

must be done to comply with another

party's contract or regulation calling for such traceability. However, NIST

can and does provide technical advice on how to make measurements consistent with national standards.

G Reference to NIST

Advertisements

NIST test results or reports shall not be used to indicate or imply that the

National Institute of Standards and

Technology approves, recommends,

2
or endorses the manufacturer, supplier, or user of any instruments or or standards or that NIST in any way

guarantees or predicts the future per- formance of items after calibration or

test. No reference shall be made to NIST or to reports or results fur- nished by NIST in any advertising or

sales promotions which would indi- cate or imply that NIST approves, recommends, or endorses any proprietary product or proprietary material.

(For more information, please re- quest Letter Circular 1128).

If you have a technical question

concerning a specific service, contact

directly one of the NIST staff members responsible for that calibration

area. Consult the section of this guide

that describes the service in question

for names, addresses, and telephone

numbers.

H Disclaimer

Commercial products — materials and

instruments — are identified in this document for the sole purpose of adequately describing experimental or

test procedures. In no event does

such identification imply recommendation or endorsement by the National Institute of Standards and

Technology of a particular product; nor does it imply that a named material or instrument is necessarily the

best available for the purpose it serves.

Questions and Inquiries

This Users Guide is designed to make

the task of selecting and ordering an

appropriate calibration service as quick and easy as possible. Nevertheless, questions will arise. When they

do, we urge you to call or write for immediate clarification. Address general questions and lengthy inquiries

to:

Physical Measurement Services

Program

National Institute of Standards and

Technology

Building 411, Room A112

Gaithersburg, MD 20899-0001

Telephone: (301) 975-2002

Telefax: (301) 975-2128

3
Chapter

Turnaround Time

B Prearrangements and Scheduling

C Purchase Order

D Shipping, Insurance, and Risk of Loss
1

t)rdering Instructions — Domestic Customers

Turnaround Time

Normal turnaround time for NIST

calibration services varies greatly—

usually from several weeks to six months — depending on the type of

service requested and fluctuations in workload. Some services are only pro- vided on a scheduled basis with ap- pointments made many months in advance of the service date. To avoid

unnecessary scheduling or administrative delays in the calibration process, always make prearrangements with

the technical contact for the service

you intend to utilize. See section B

for more information on Prearrange- ments. B Prearrangements and

Scheduling

Services are best arranged in advance,

beginning with a call or letter from

the customer to a NIST staff member

directly responsible for the desired

service. See the appropriate technical

section of this Users Guide or the

separate Fee Schedule to determine

whom to call or write. This advance

communication can clear up any

questions you may have, clarify the

policies and procedures briefly described here, and permit you to tentatively schedule a calibration date. Following the initial communication,

you will immediately need to fill out and send in a purchase order and

prepare and ship the item according

to the procedures described below. If a calibration must be scheduled far in advance, you may arrange to delay

shipment of the item until shortly before the scheduled date; you must

however, submit the purchase order —

complete with the name and number

of the desired service — before a firm

calibration date can be assigned.

When NIST receives your valid pur- chase order and assigns a firm service

date, you will be notified by mail to confirm the order.

Purchase Order

Send a purchase order to the address

listed in the appropriate technical

section of this Users Guide, or in the

separate Fee Schedule, before you

ship an item for calibration. The

purchase order must:

1) State both the name and

number of the NIST service being requested. FAILURE

TO INCLUDE THE ORDER

NUMBER WILL SERIOUSLY IMPEDE SCHEDULING AND SERVICE.

2) Clearly identify the item(s)

being sent for calibration, in- cluding any serial number(s).

3) Give the name, address, and

telephone number of the re- questing company's procurement officer. 4) Give the name, address, and

telephone number of the re- questing company's technical

contact, if different from

above.

5) List separately the instructions

for return shipment, insurance,

mailing of the test report, and

billing. (Federal or state agency requests for calibration

services should be accompanied by a document authorizing

that the cost of the service be

billed to the agency.)

6) Clearly state any special or necessary conditions of test —

such as operating frequency

or temperature.

7) Clearly state the customer

identification number; i.e., social security number (EIN)

for consumer customers; tax

identification number (TIN)

for commercial customers; or agency location code (ALC)

for government customers.

8) Give instructions on the pur- chase order, if the final report

is to be handled in a special manner.

5
PLEASE NOTE: Receipt of orders

by NIST does not imply acceptance of

any provisions set forth in the order

that are contrary to the poHcy, practice, or regulations of the National

Institute of Standards and Technology or the U.S. government. In general, NIST will not sign any affidavits,

acknowledgment forms, or other

documents that may be required by

company policy governing the pro- curement of goods and services. D Shipping, Insurance,

g and Risk of Loss

Ship an instrument or standard to the

address to which you mailed your

purchase order. Adhere rigorously to the following procedures:

1) Ship only items in good repair.

Apparatus in disrepair will not be calibrated. If defects are found after calibration has be- gun, the procedure will be ter- minated, a report issued, and a charge levied for work completed.

2) Use strong, reusable packing

materials and containers

marked clearly and indelibly on

the outside with the requestor's

name, address, and the following notation: REUSABLE

CONTAINER, DO NOT DESTROY.

3) Follow any special shipping

procedures given in the technical sections of this guide, particularly those sections covering

radiation and dosimetry measurements.

4) Insure the shipments to and

from NIST and clearly state the method of return shipment.

NIST will not assume liability for loss or damage unless such

loss and damage result solely

from the negligence of NIST

personnel. If return shipment

by parcel post is requested or

is suitable, NIST will prepay

the return shipment but will not insure it. When no shipping or insurance instructions are furnished, NIST will return

the shipment by common carrier, collect and uninsured.

PLEASE NOTE: Fees for NIST

services do not include shipping costs.

6

Chapter

Criteria for Providing Service Q Special Instructions Q Foreign Inquiries
special Instructions — Foreign Customers

Criteria for Providing

Service

The National Institute of Standards

and Technology is authorized to provide measurement services, including calibrations, for organizations or

individuals located outside the United

States. NIST policy requires that the

Physical Measurement Services Pro- gram review each request to deter- mine if such a service is available in the requestor's country. Foreign cus- tomers must provide the following in- formation:

1) A justification why NIST

should perform this service, if an official standards laboratory

in the country of the re- questor's provide such service. 2) A description of the instrument

or standard to be tested, particularly if it is not manufactured in the U.S.

3) A detailed description of the

measurements that are needed

or indicate the test order number as given in the Calibration

Services Users Guide (NIST

SP 250) or the separate Fee

Schedule (NIST SP 250 Appendix),

4) A description of any special re- quirements that might affect the decision to provide the service. For example, will a need

exist for adjustments to the in- strument or will the time period be restricted in which the

device is available for measure- ment?

Special Instructions

If the request for the measurement

service is accepted by NIST, the re- questing organization will be notified

of the cost of service and will be

given the identification of the NIST

laboratory that will perform the

measurements. The requesting

organization must then complete the

following steps:

1) Contact the NIST technical

unit that will provide the ser- vice to determine the schedule.

2) Send a purchase order to the

Physical Measurement Services

Program. Provide complete addresses for returning the in- strument and for mailing the

calibration or test report.

3) Send a check payable in U.S.

dollars to the Physical Measurement Services Program for the full cost of the service. The

check must be drawn on a U.S. bank. NIST cannot begin the

service until full payment has

been received.

4) Ship the instrument or stan- dard to the appropriate NIST

technical unit, as specified in the Calibration Services Users

Guide (NIST SP 250) or the

separate Fee Schedule (NIST

SP 250 Appendix). You must

prearrange shipment with a customs broker for entry of the

instrument into the U.S. with

prepaid transportation from

the port of entry. Air freight is most satisfactory. Entry bond is required for instruments not manufactured in the U.S. If arrangements are made with a broker in the country of origin, that broker should, in turn, have a U.S. customs broker in or near the port of entry who

must arrange for the entry of

the instrument and its trans- portation to NIST. Direct ar- rangements can be made with

customs brokers located in the

Washington, DC/Baltimore,

MD, metropolitan area or in the Denver, CO, area, as appropriate. These brokers

must also arrange for trans- portation to the port of exit after testing is completed.

9
Foreign Inquiries

Foreign customers requiring additional information or clarifications can get assistance by addressing all telephone calls or correspondence

to:

Physical Measurement Services

Program

National Institute of Standards and

Technology

Building 411, Room A112

Gaithersburg, MD 20899-0001

United States of America

Telephone (301) 975-2002

Telefax (301) 975-2128

Telex: TRT 197674NIST UT

Visit our exiiibit booth at tine next meeting you attend.

10

Chapter

A Length Measurements

B Diameter Measurements

C Complex Dimensional Standards

D Optical Reference Planes &

Roundness Standards

E Angular Measurements

F Laser Measurements

G Surface Texture H Hydrometers

1 Volume and Density
Dimensional Measurements 10010C-1(XJ60S

Length Measurements

Technical Contacts: Ralph veaie

Tel: 301/975-3502

John R. Stoup William B. Penzes Ronald G. Theodore D. 10010C-10050S 10020C Hartsock Doiron

Tel: 301/975-3471 Tel: 301/975-3477 10030C-10040C 10060S

Tel: 301/975-3465 Tel: 301/975-3468

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items lOOlOC Gage Blocks

10020C Line Standards

10030C Surveying and Oil Gaging Tapes

10040S Special Tests of Surveying Leveling Rods

10050S Special Tests of Length Standards

10060S Special Tests of Sieves

Gage Blocks (lOOlOC)

This calibration service provides for measurement of the length of gage

blocks by either comparison to NIST

master gage blocks or by direct inter- ferometry. Generally, the length is transferred from knov^n master blocks

by a systematic intercomparison pro- cedure using mechanical comparators.

Comparators with laser scales are also

available. All gage blocks submitted for test should be in substantially new block

condition, and each block should be

marked with an identification number.

In shipping gage blocks, extreme care should be taken against both corrosion and damage by contact with

other gage blocks. All defining steel surfaces should be greased and blocks

padded with waxed paper or volatile rust inhibitor treated paper. A

greased steel surface coming in contact with newspaper, wrapping paper

(unwaxed), or excelsior is likely to

corrode. Sets of gage blocks should

have packing inside the case and the case should be bound shut, as the

clasps frequently open or break during shipment.

Square or rectangular blocks or

lengths up to 20 inches are routinely

calibrated and the lengths reported in English or metric units. For blocks

longer than 20 inches, the NIST technical contact should be consulted in advance to discuss alternative measurement techniques, approximate

costs, and scheduling.

The measurement uncertainty re- ported is the sum of the random er- ror in the measurement of the block

under test and the estimated systematic error in the measurement process. The process used to estimate

this systematic error is documented in publications referenced in this catalog. Although the uncertainty varies

slightly with each measurement, the

variation is usually small. A reasonable estimate for the accuracy of the

calibration is 2 microinches (0.05

micrometer) for blocks under 2

inches, and with accuracy decreasing

with length to 10 microinches for the

20-inch blocks.

Line Standards (10020C)

Line standards of 1 meter or less are measured on an instrument called a

line scale interferometer, which is used to measure the distance between

suitable lines on a flat surface. The in- strument employs a fixed photoelectric microscope to determine the

position of the scale lines, a linearly

mobile carriage in the focal plane of

the microscope to carry the scales, a calibrated laser interferometer to measure carriage displacement, and a temperature-controlled housing enclosing the whole apparatus.

The system is now highly auto- mated using a laboratory microcomputer, NIST-developed optical

processing, and servo electronics. With the microscope focused on the

scale zero line, a servo moves the

13
10010C-10060S

carriage until a null signal indicates

the line is centered in the microscopic

field. A stepping motor then drives

the carriage until the next line on the

scale is reached. Servoed line centering again takes place. The carriage is now moved precisely the distance between scale lines, and the interferometer has now measured this distance

in laser light wavelengths. Proceeding

down the scale in this manner results

in the measurement of the line spacings.

The maximum length of line stan- dards that can be measured is 1 meter, and the maximum width of any

part of the piece being calibrated

cannot exceed 150 millimeters. The

accuracy of the calibration depends

significantly on the shape and optical

properties of the line, the background, and the geometric flatness of

the artifact being calibrated. If the

lines have straight edges and are 2 to 10 micrometers wide, if there is good

contrast between the line and the

background, and if the reference sur- face of the artifact is flat, then the ac- curacy of the calibration will be near

^1 .Am 1 K f

Pictured above is the line scale interferometer used for calibrations of line standards up to 1 meter in length.

optimum. Uncertainties as low as 0.006 micrometer have been achieved on short intervals, and on 1-meter

lengths uncertainties of 0.1 micrometer can be achieved. The current

overall system accuracy is limited by

imprecise knowledge of the refractive

index of air.

Surveying and Oil Gaging Tapes

(10030C)

The calibration of surveying tapes

and oil gaging tapes is carried out in a laboratory that houses two permanent working standards, a laser inter- ferometer, and a 50-meter (200-foot)

stainless steel bench. For the most

part measurements are performed us- ing a laser system that is referenced

against a cube-corner retroreflector attached to a microscope, which is used manually for line location. The

laboratory is maintained at 20 °C, but

a control system can vary the chamber temperature from 15 to 40 °C for

special tests. Calibration of tapes will normally be made with the tape

under tension and supported on a

horizontal-flat surface. Unless otherwise requested, the total length and

each 15-meter or 50-foot subinterval

will be measured and reported. Each

interval calibrated on a surveying tape

will have computed lengths for two

(single catenary), three, four, and five equidistant points of support.

The laser standard is capable of

calibrating tapes with scribed graduations to an accuracy of 2 parts per

million (ppm). Calibrations made

with respect to the stainless steel tape

bench are normally reported to an

accuracy of 10 ppm. A NIST serial number will be engraved on each cali- brated tape for identification.

14
10010C-10060S

Figure 1 summarizes the accuracy

of length measurements at NIST. In- cluded are the NIST 5-meter bar,

gage block calibrations, end line stan- dards, and geodetic/steel tapes.

Figure 1. Accuracy of Length Measurements at NIST

I I 1 I I I I I I I I 10"^10"'10"M0"M0"''10"^ 10"'10° 10' 10' 10^ 10"

Length, inch __i I I I I I I I I I I i_

10"^10"^10"'10"^ 10"^10""lO"^10"hO"'lO° 10' 10'

Length, meter

Special Tests of Surveying Leveling

Rods (10040S)

Leveling rods are currently calibrated

using two methods. One method

involves the comparison of the rod to a 3-meter standard at the 1-, 2-, and

3-meter intervals. A second system

provides measurement at multiple

intervals and automatic report generation. This automated system incor- porates a 7-meter one-dimensional

measuring machine, a motorized

carriage, a photoelectric microscope,

and a helium-neon laser interferometer interfaced to a minicomputer.

Measurements can be made on

virtually any type of linear scale or

leveling rod with scribed, engraved, or painted graduations. The random er- ror of measuring high-quality leveling

rods is plus or minus 6 micrometers

for new rods and plus or minus 12

micrometers for used rods at the one

standard deviation level. The systematic errors are largely unevaluated,

and to account for their existence

the total error being reported by

NIST at present is plus or minus 50

micrometers for new rods. The length

of intervals will be reported as measured at 20 °C unless otherwise

requested. The report can be supplied in either written or computerreadable form.

Special Tests of Length Standards

(10050S)

Measurements on end standards with

spherical ends, gage blocks of unusual

shape or exotic materials, or measure- ment of standards between 24 and

240 inches can sometimes be done,

but agreement with the technical contact should be made before sending

material.

Special Tests of Sieves (10060S)

To determine conformity to ASTM

Ell specifications.

References — Length Measurements

Grid Plate Calibration at the

National Bureau of Standards, T. D.

Doiron, J. Res. Natl. Bur. Stand.

(U.S.), 93, No. 1 (Jan.-Feb. 1988).

Interferometric Measurement of

Length Scales at the National

Bureau of Standards, J. S. Beers and

K. B. Lee, Prec. Eng., 4, No. 4, 205

(Oct. 1982).

Contact Deformation of Gage Block

Comparisons, J. S. Beers and J. E.

Taylor, Natl. Bur. Stand. (U.S.),

Tech. Note 962 (May 1978).

Intercomparison Procedures for Gage

Blocks Using Electromechanical

Comparators, J. S. Beers and C. D.

Tucker, Natl. Bur. Stand. (U.S.),

NBSIR 76-979 (Jan. 1976).

15
10010C-10060S

A Gage Block Measurement Process Using Single Wavelength Interfer- ometry, J. S. Beers, Natl. Bur.

Stand. (U.S.), Monogr. 152 9Dec.

1975).

Preparations for Gage Block Comparison Measurements, C. D.

Tucker, Natl. Bur. Stand. (U.S.),

NBSIR 74-523 (July 1974).

Gage Block Flatness and Parallelism

Measurement, J. S. Beers and

C. D. Tucker, Natl. Bur. Stand.

(U.S.), NBSIR 73-239 (Aug. 1973).

An Automatic Fringe Counting Inter- ferometer for Use in the Calibration of Line Scales, H. D. Cook

and L. A. Marzetta, J. Res. Natl. Bur. Stand. (U.S.), 65C, 129 (1961).

16
11010S-11070S

Diameter Measurements

Technical Contacts:

John R. Stoup Ralph Veale 11010S-11070S Tel: 301/975-3502

Tel: 301/975-3471

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items IIOIOS Special Tests for Plug Gages: External Diameter

Standards

11020C Measuring Wires for Threads and Gears

11030S Special Tests of Spherical Diameter Standards: Balis 11040S Special Tests of Internal Diameter Standards: Ring

Gages

11050S Special Tests of Length and Diameter

11060S Special Tests of Step Gages

11070S Special Diameter Measurement, by Prearrangement

General Information

For controlling dimensions in the

manufacture of all products, various

types of dimensional gages are used.

The variety of such gages measured

includes cylindrical plug gages, ring gages, balls for diameter, and screw

thread gages. The diameter standards

and gages, with the exception of

thread and gear measuring wires, are generally intended to be used as comparison masters.

Special Tests for Plug

Gages: External Diameter Standards

(IIOIOS)

NIST will provide calibrations of ex- ternal diameter standards by special

arrangement. Please consult with the

technical contacts listed above.

Measuring Wires for Threads and

Gears (11020C)

This service provides for measure- ment of the diameter of thread and

gear measuring wires by intercompari- son to NIST Master wires. The di- ameter is transferred from known

Master wires using a systematized in- tercomparison sequence with a mechanical comparator.

All measuring wires submitted for

test should be in substantially new

condition, each wire should be appropriately bottled, and the bottle should

be labeled with an identification number. In shipping thread wires, extreme

care should be taken to prevent corrosion; all wires should be properly

greased and their bottles rigidly contained inside an appropriate packing

case. Thread measuring wires for 60- degree and 29-degree threads are

tested for compliance with the latest specifications in commercial use. These wires are calibrated, and the

pitch diameter is computed. Gear

measuring wires in the 1.927P, 1.7287

P, 1.68"/P, and 1.447P series are

tested for compliance with the latest specifications in commercial use and

the mean diameter reported.

Accuracies are reported to a 3-sigma

confidence level of 5 microinches for English wires and 0.12 micrometer for metric wires.

Special Tests of Spherical Diameter

Standards: Balls (11030S)

Balls used in precision bearings and

master balls used as transfer diameter

standards are calibrated according to current commercial practice. The ball diameters reported are the undeformed sizes as calculated with the

Hertz relations to maintain a consistency in reported sizes.

Special Tests of Internal Diameter

Standards: Ring Gages (11040S)

NIST will provide calibrations of ring

gages by special arrangement.

Please consult with the technical contacts listed.

17
Special Tests of Length and Diameter

(11050S)

NIST has a wide variety of state-of- the-art metrology equipment and can

provide services associated with

dimensional quality control as special

tests. A three-dimensional measuring

machine is available for calibration of two- and three-dimensional ball plates, two-dimensional grid plates,

and other artifacts of complex shape.

The machine has a working volume of

48 X 24 X 12 inches and can detect a length difference of 0.013 micrometer. Reference to the international

standard of length is through interfer- ometers. Uncertainties in the calibra- tions are variable. Spherical diameter

standards, such as balls used in precision bearings and master balls used as transfer diameter standar Js, are cali- brated using a laser-based mechanical

comparator.

Special Tests of Step Gages (11060S)

Step gages having flat parallel faces can be measured in lengths up to one meter.

Special Diameter Measurements, by

Prearrangement (11070S)

For requirements not covered by the

services described above, special ar- rangements may be made by contacting Ralph Veale (301) 975-3468.

References — Diameter Measurements

Federal Standard H-28, Screw Thread

Standards for Federal Services. English and metric versions. These

handbooks are available from the

General Services Administration

(GSA).

American National Standard B1.2,

Amer. Natl. Stand. Inst., New

York.

Designs for the Calibration of Small

Groups of Standards in the Pres- ence of Instrumental Drift, J. M.

Cameron and G. E. Hieles, Natl. Bur. Stand. (U.S.) Tech. Note 844

(Aug. 1974).

On the Measurement of Thread

Measuring Wires, B. N. Norden,

Natl. Bur. Stand. (U.S.), Report

10987 (Jan. 1973).

Measurements of Cylindrical Standards, R.C. Veale, Natl. Bur.

Stand. (U.S.), NBSIR 73-136

(1973).

On the Comparison of Cylinder in Contact with a Plane Surface, B. Norden, Natl. Bur. Stand. (U.S.),

NBSIR 73-243 (1973).

18
12010C-12040S

Complex Dimensional Standards

Technical Contacts:

Edgar G. Erber Theodore D. Ralph Veale 12010C-12020S Doiron Tel: 301/975-3502

Tel: 301/975-3468 12030S

Tel: 301/975-3468

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 12010C API Threaded Plug and Ring Gages

12020S Special Tests of Threaded Plug and Ring Gages

12030S Special Tests of Two-Dimensional Gages

12040S Special Complex Dimensional Tests, by

Prearrangement

API Threaded Plug and Ring Gages

(12010C)

NIST provides calibration and certifi- cation services for API threaded plug

and ring gages, casing, tubing and line pipe plug and ring gages as well as sucker rod gages. NIST is the custo- dian of the American Petroleum Institute (API) Grand Master rotary

thread gages. These Grand Master

gages are maintained and have been

recalibrated at NIST for more than

60 years. They can be considered an

international standard since all API

Regional Master Gages throughout

the world are referenced to NIST.

Foreign product manufacturers can have their Reference Master Gages

calibrated and certified by NIST or by one of the other national standard

laboratories listed below:

National Physical Laboratory,

Teddington, England

National Research Laboratory of

Metrology, Tokyo, Japan

National Standards Laboratory,

Chippendale, N.S.W., Australia

Physikalisch Technische Bundesanstalt, Braunschweig, Germany

Laboratoire National d'Essais,

Paris, France

Instituto Nacional de Technologia

Industrial, San Martin, Argentina

As required, the API lab is temperature controlled at 20 °C. Parameters

measured for plug gages are length of

plug, taper, pitch diameter, major di- ameter, thread lead, lead and follow- ing thread half-angles, depth of

thread, pitch line width, and radius of

curvature. Parameters measured for ring gages

are length of ring, taper, thread lead,

minor diameter, lead and following

thread half-angles, counter bore,

depth of thread, pitch line width, ra- dius of curvature, and standoff. These calibrations are based on a three standard deviation confidence

level and are accurate to plus or mi- nus 0.0003 inch (8 mm).

All gages received must be marked

with the API monogram and the API

registration number. If not so marked

the gages will be returned to the cus- tomer uncalibrated. Gages which

meet the specifications will be

marked as specified in the API Standards. All thread gages must be submitted in sets of plug and ring. The name of the gage owner should be

given for inclusion in the Report of

Calibration.

Special Tests of Threaded Plug and

Ring Gages (12020S)

NIST will provide special tests of

threaded plug and ring gages. Please

consult the technical contact listed.

19
12010C-12040S

Special Tests of Two-Dimensional

Gages (12030S)

NIST can provide special tests of two- dimensional gages, ball plates, or grid

plates, with dimensions up to 24

inches by 24 inches (0.6 x 0.6 meters).

The accuracy of such calibrations depends substantially on the quality of

the gage, but accuracies of one

micrometer or better are obtainable.

Special Complex Dimensional Tests,

by Prearrangement (12040S)

For requirements not covered by the

services described above, special

arrangements may be made by contacting Ralph Veale (301) 975-3502.

References — Complex Dimensional

Standards

On Characterizing Measuring Machine Geometry, R. J. Hocken and

B. R. Borchardt, Natl. Bur. Stand.

(U.S.), NBSIR 79-1752 (1979).

Three-Dimensional Metrology, R. J. Hocken et al.. Annals of the CIRP,

26-1 (1977).

Unified Three-Dimensional

Program — Two Useful NonContacting Probes, J. A. Simpson,

Natl. Bur. Stand. (U.S.), Report

10597 (1971).

NIST provides calibration arid certification sen/ices for American Petroleum Institute (API) gages, including threaded plug and

ring gages, casings, tubing and line pipe

plug and ring gages, and sucker rod

gages. NIST has maintained and recali- brated the API grand master rotary thread

gages for more than 50 years.

20
13010S-13030S

D Optical Reference Planes &

Roundness Standards

Technical Contacts:

John R. Stoup Yun H. Queen Ralph Veale 13010S 13020S-13030S Tel: 301/975-3502

Tel: 301/975-3741 Tel: 301/975-3468

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items

13010S Special Tests of Optical Reference Planes (Flats) 13020S Special Tests of Roundness

13030S Special Tests of Roundness Calibration Specimens

Special Tests of Optical Reference

Planes (13010S)

Optical reference planes are tested

interferometrically, horizontally sup- ported with the test surface sup- ported on three equally spaced pads

located at 0.7 of the radius from the

center. The measurement is per- formed along two marked diameters

at 90° to each other on each surface

when each diameter is parallel to two

of the support pads.

Roundness Calibration Specimens

and Measurements, Special Tests of

Roundness (13020S and 13030S)

The deviation from roundness at eight or more positions around nominally round standards is determined.

The size of the calibration step or deviation from roundness on calibration

standards is determined. The departure from roundness of components

and gages is measured, and the re- sults are reported in graphical form.

NIST will provide special tests of

roundness calibration specimens by

request. Please consult with the technical contacts listed.

References — Optical Reference Planes

The Calibration of an Optical Flat by

Interferometric Comparison to a Master Optical Flat, C. P. Reeve,

Natl. Bur. Stand. (U.S.),

NBSIR 75-975 (Dec. 1975).

A Survey of the Stability of Optical

Flats, C. P. Reeve and R. C. Veale,

Natl. Bur. Stand. (U.S.), NBSIR

73-232 (June 1973).

21
14010C-14050S

Angular Measurements

Technical Contacts:

Yun H. Queen

Tel: 301/975-3468 Ralph VealeTel: 301/975-3502

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 14010C Angle Gage Blocks 14020S Special Tests of Optical Polygons

14030S Special Tests of Rotary and Indexing Tables

14040S Special Tests of Wedges

14050S Special Angular Measurements, by Prearrangement

Angle Gage Blocks (14010C)

This service provides for the measure- ment of the angle of angle gage

blocks by direct comparison to NIST

master angle blocks using a dualautocollimator system. Current auto- collimators have resolution to 0.01 arc-second and electronic readout.

The blocks are enclosed in a special

chamber during intercomparison to minimize air currents, and the laboratory is maintained at 20 °C to within

plus or minus 0.1 degree.

All angle gage blocks submitted for

test should be in substantially new

block condition, and each block

should be marked with an identifica- tion number. In shipping angle blocks

the same care as is exercised in gage

block shipment should be used, as the

surfaces are subject to corrosion.

All standard sizes of angle blocks can be calibrated in the NIST facilities. Blocks with angles ranging from

1 arc-second to 45 degrees are routinely handled; however, optical

squares and other standards can also be accommodated. Accuracy at the 3- sigma level is approximately 0.4 arc- second; this value, however, varies

with the condition of the gaging sur- face on the standard.

Special Tests of Optical Polygons

(14020S)

The calibration of polygons is done

with autocollimation techniques. It consists of the determination of flat- ness of each face, variation of the angle between each face and the base

(where possible the polygon will be

adjusted for minimum variation), and

the angle between faces. Figure 2

summarizes the precision of angle cal- ibration for master angle gage blocks

and polygons.

Figure 2. Precision of Angle Calibrations for Master

Angle Gage Blocks and Polygons

10'

10"

10'

10^

10^

10=

10

1

trwa

0)co

Angular Measurement by

Direct Interferometry Angle Gage Blocks by

Angular Subdivision Polygons by Complete c, ^^^o ' Circular Closure . <:oSj^^ " 4y

72-36,

12 10_654 ^^^^

o^l^^' 20^^

1 ° ' 30°^

3°v15°l

" 5° 24

°45°

Direction of Constant

Angular Error Lines

I 1—1- 10" 10" 10"

"Based on 3 standard

deviations. Systematic

errors may be of the same order of magni- tude as ttie precision

of determination.

10-^ Degrees

1 2 3 5 10 20 50100

T" 5 20 50 2 5 10 20 50

Seconds Minutes

22
14010C-14050S

Special Tests of Rotary and Indexing

Tables (14030S) Instruments and tools used for the

precise measurement of angle, such

as precision angular rotary and indexing tables, autocollimating telescopes, or angle generating equipment, are

calibrated at specific angular settings.

Accuracy at the 3-sigma level is ap- proximately 0.2 arc-second.

Special Tests of Wedges (14040S)

Solid angle calipers and step mirrors

are calibrated by autocollimation or

interferometric techniques as to the

angle between faces. Wedges are cali- brated by autocollimating or interfer- ometric techniques at a specified

wavelength for deviation angle. Mechanical angular references such as

cylindrical squares and machinist's

squares are usually calibrated by

mechanical techniques.

Special Angular Measurements, by

Prearrangement (14050S)

For requirements not covered by the

services described above, special ar- rangements may be made by contacting Ralph Veale (301) 975-3502.

References— Angular Measurements

The Calibration of Angle Blocks by

Intercomparison, C. P. Reeve, Natl. Bur. Stand. (U.S.), NBSIR 80-1967

(1980).

The Calibration of Indexing Tables by

Subdivision, C. P. Reeve, Natl. Bur.

Stand. (U.S.), NBSIR 75-750 (July

1975).

A Survey of the Temporal Stability of

Angle Blocks, R. C. Veale and C.

P. Reeve, Natl. Bur. Stand. (U.S.),

NBSIR 74-601 (Nov. 1974).

23
145 lOS

Laser Measurements

Technical Contacts:

Jack Stone

Tel: 301/975-5638 Ralph VealeTel: 301/975-3502

Mailing Address: A107 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items

145 lOS Laser FrequencyAVavelength

Laser FrequencyAVavelength

(14510S)

The frequency (or, equivalently, the vacuum wavelength) of a red He-Ne

laser is determined by comparison

to an iodine-stabilized He-Ne laser. The technique has a potential accuracy of about 6 parts in ten to the

tenth. As a practical matter, however,

accuracy is usually limited by the

stability of the laser under test.

24
15010C-15030C

Surface Texture

Technical Contacts:

Arie Hartman Cynthia K. Rymes

Tel: 301/975-3475 Tel: 301/975-4081

Mailing Address: All 7 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 15010C Roughness Calibration Specimens

15020C Surface Roughness Comparison Specimens

15030C Step Height Measurements

Roughness (15010C-15030C)

NIST provides measurement services

in three categories: instrument cali- bration specimens (with regular geo- metric profiles), roughness comparison (and other types of roughness

specimens), and step height speci- mens. The property of surface roughness

up to 10-|jLm Ra and of step heights

up to 25 |jim are measured by means

of a minicomputer/stylus instrument

system. Using an interferometrically

measured step, the system is cali- brated at each value of magnification

employed during a measurement.

In measurements of roughness, sur- face profiles are taken according to American National Standard

B46.1-1985 using a 0.8-mm cutoff

length and a traversing length of 4 mm. A number of other statistical parameters and functions may be cal- culated, including the rms roughness,

average slope, average wavelength,

skewness, amplitude density function,

autocorrelation function, and power

spectral density.

In step height measurements, a

straight line is fitted by the method of

least squares to each side of the profile of the step and to the middle,

and the step height is calculated from

the vertical difference between the

middle area and each side. The uncertainty in the NIST cali- bration for step height or Ra depends

on a number of factors, the most important being the step or Ra value it- self. The uncertainties range from

approximately 0.4 \im at a step height

of 25 ^.m to 0.002 p,m at the smallest

step heights. Comparable uncertainties are achieved for measurements of

Ra.

References — Surface Texture

Characterization of Surface Topography, T. V. Vorburger and G. G.

Hembree, in Navy Metrology R&D

Prog. Conf. Report, Corona, CA

(Apr. 1989).

Measurements of Roughness of Very

Smooth Surfaces, T. V. Vorburger,

Annals of the CIRP 36, No. 2, 503

(1987).

Direct Comparison of Mechanical

and Optical Measurements of the

Finish of Precision Machined Optical Surfaces, E. L. Church, T. V. Vorburger, and J. C. Wyant, Optical Engineering 24, 388 (1985).

Sinusoidal Profile Precision Roughness Specimens, E. C. Teague,

F. E. Scire, and T. V. Vorburger,

Wear, 83, 61 (1982).

Three-Dimensional Stylus Profilometry, E. C. Teague, F. E. Scire,

S. M. Baker, and S. W. Jensen,

Wear, 83, 1 (1982).

25
FASTMENU: A set of FORTRAN

Programs for Analyzing Surface

Texture, T. V. Vorburger, Natl. Bur. Stand. (U.S.), NBSIR 83-2703

(July 1982).

Optical Techniques for On-Line Measurement of Surface Topography,

T. V. Vorburger and E. C. Teague,

Free. Eng., 3, 611 (1981).

Uncertainties in Calibrating a Stylus

Type Surface Texture Measuring

Instrument with an Interferometrically Measured Step, E. C. Teague,

Metrologia, 14, 39 (1979).

Measurements of Stylus Radii, T. V. Vorburger, E. C. Teague, F. E.

Scire, and F. W. Rasberry, Wear,

57, 39 (1979).

FAST Facility Available for Engineering Needs, T. V. Vorburger, E. C. Teague, and F. E. Scire,

Dimensions/NBS, 62, 18 (1978).

Evaluation, Revision, and Application

of the NBS Stylus/Computer System for the Measurement of Surface Roughness, E. C. Teague,

Natl. Bur. Stand. (U.S.), Tech.

Note 902 (Apr. 1976).

Precision Reference Specimens of

Surface Roughness: Some Characteristics of the Cali-Block, R. D.

Young and F. E. Scire, J. Res.

Natl. Bur. Stand. (U.S.), 76C (Eng.

and Instr.), Nos. 1 and 2, 21 (Jan.-

June 1972).

26
Hydrometers

Technical Contacts:

John F. Houser George E. Mattingly

Tel: 301/97S-S9S6 Tel: 301/975-5939

Mailing Address: 105 Fluid Mechanics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 16010C Reference Standard Hydrometers

Reference Standard Hydrometers

(16010C)

NIST provides measurement services for reference hydrometers. These ref- erence standard hydrometers are generally used as laboratory standards to calibrate other hydrometers. Refer- ence hydrometers submitted for test should be made of smooth, transpar- ent glass, free of bubbles or other imperfections. The hydrometer should

bear an inscription which indicates

the purpose of the instrument. This

inscription should denote the refer- ence temperature at which it is to be

used. The maker's name or trade

mark and an identification number

should be inscribed on the hydrometer scale. Hydrometers accepted for calibration must comply with ASTM

(ElOO) specifications and the requirements of NBS Circular 555, "Testing

of Hydrometers".

Reference Hydrometers accepted

for calibration may include specific

gravity proof spirit for alcohol solutions, API degrees for petroleum

measurements, degrees Baume heavy

and degrees Baume light, and other

arbitrary scales; however, in all cases,

details regarding particular requirements must be arranged in advance.

Specific gravity hydrometers cover the

range of 0.65 to 2.0 specific gravity.

The hydrometer scale should be di- vided into 0.001, 0.0005, 0.0002, or

0.0001 units of the density. Proof

spirit hydrometers cover the range of

0 to 200 proof. The hydrometer scale should be divided in whole, half, fifth or tenth percents.

Visual inspection should be made

by the customer before submitting the

hydrometer for calibration. The hydrometer should be packed in a safe,

reusable shipping container.

NIST will provide a three point cal- ibration of these reference hydrometers. Additional points will be

provided, if requested, for an additional charge. The calibration at NIST consists of comparing NIST

master hydrometers with the cus- tomer's hydrometers in an appropriate liquid having low surface tension.

Readings and corrections to readings are reported to one-tenth of a

scale division. The uncertainty of

these values may vary with the instru- ment design and a general statement cannot be made. Considerations re- garding uncertainty can be discussed

at the time that arrangements are made for the calibration of any particular instrument; a statement of uncertainty for the NIST master

hydrometers used in the calibration

will be included in the calibration re- port.

27
17010C-17040S

Volume and Density

Technical Contacts:

John F. Houser George E. Mattingly

Tel: 301/975-5956 Tel: 301/5939

Mailing Address: 105 Fluid Mechanics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 17010C Volume Standards

17020S Special Tests of Volume Standards

17040S Special Tests of Density: Liquids

Volume Standards (17010C)

The procedure used for testing glass

volumetric apparatus is to weigh the

amount of distilled water contained

or delivered with reference to the

graduations marked on the instru- ment, the volume being computed

from the density of the water. (Refer- ences provided upon request.) The

quality of the markings and the care

exercised in reading or setting the liquid level are major factors in test cali- bration and usage. NIST does not provide routine calibration services

for glassware; however, NIST will ac- cept factory standards and replacement glassware for the State Weights

and Measures Departments, in the

range of 10~^ L to 5 liters, which con- form essentially to requirements contained in NBS Circular 602, "Testing

of Glass Volumetric Apparatus,"

Federal Procurement Specifications

NNN-B-00789 (Buret, straight, precision), NNN-F-00289a (Pipet, volumetric), NNN-P-0035a (Pipet,

measuring), or NNN-F-00289a (Flask,

volumetric), if such instruments

are to be used as reference or transfer standards.

NIST provides a calibration service

for metal volumetric test measures. These volumetric test measures ac- cepted for calibration should comply

with the specifications contained in NBS Monograph 62, "Testing of Volumetric Standards." These test measures should be free from dents, rust, or scratches. Special care should be

taken by the customers to insure the

cleanliness of the inside of the test measures. Should the test measure be

equipped with a bottom drain valve, it

is the customers's responsibility to in- sure that the valve is in sound working condition. These test measures

should bear an inscription which indi- cates the nominal volume at a refer- ence temperature, the assumed

thermal coefficient of expansion, and

an identification number. The scale plate should be legible so that the

scale division can be estimated to one-tenth of a single division. A scale

calibration is provided as part of the

calibration; however, NIST does not

adjust scales. The zero index or the

gage scale should, therefore, be adjusted prior to calibration. The slicker plate type volume standards should

be adjusted by the manufacturer.

Normally NIST will accept for cali- bration test measures that have nominal volumes in the range of 1 gallon

to 1500 gallons or 5 liters to 7500

liters. The calibration procedure for these test measures consists of determining the volume "to contain" or

"to deliver" by either gravimetric determinations, which is the result of di- rect comparisons with mass standards,

or by the use of transfer standards,

for which volumes have been pre- determined. NIST will perform two

independent measurements for each

volume standard submitted for cali- bration. An overall uncertainty of

±0.04 percent is usually assigned to

all metal volumetric standards at the

present time. NIST is currently in- volved in a program to improve liquid

volume measurement accuracies.

28
17010C-17040S

Special Tests of Volume Standards

(17020S)

Special tests may be made of volume

standards by prearrangement with

technical contacts cited in this section.

Special Tests of Density: Liquids

(17040S)

Currently NIST is involved in a liquid

density measurement research project; The technical contacts cited in

this section can be contacted regarding this project.

References— Volume and Density

Measurements

Calibration of Small Volumetric Laboratory Glassware, J. Lembeck,

Natl. Bur. Stand. (U.S.), NBSIR

74-461 (Oct. 1974).

The Equivalence of Gravimetric and

Volumetric Test Measure Calibration, R. M. Schoonover, Natl. Bur. Stand. (U.S.), NBSIR 74-454 (Feb.

1974).

Procedures for the Calibration of

Volumetric Test Measures, J. F. Houser, Natl. Bur. Stand. (U.S.),

NBSIR 73-287 (Aug. 1973).

29
Chapter

A Flow Rate Measurements

a Flow Measurements at Cryogenic

Temperatures

c Airspeed Measurements

D Mass Standards

E Force Measurements

F Vibration Measurements

G Acoustic Measurements

H Ultrasonic Reference Block

Measurements

/ Ultrasonic Transducer Measurements

J

Acoustic Emission Transducer

Measurements
Mechanical Measurements 18010C-18050S

Flow Rate Measurements

Technical Contacts:

G. Paul George E. Baumgarten Mattingly

Tel: 301/975-9057 Tel: 301/975-5939

Mailing Address: 105 Fluid Mechanics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 18010C Single Turbine Meters

18020C Tandem Turbine Meters

18030C Flow Rate Meters (Direct Reading in Flow Rate Units)

18040C Head Class Flow Measurement Devices

18050S Special Tests for Liquid and Gas Flow Rates

Flowmeters (18010C-18040C)

NIST provides calibration services for

liquid flowmeter systems that include

a flowmeter and pertinent adjacent

tubing, auxiliary measurement instru- mentation, and readout equipment.

Flowmeter systems having demonstrated precision and temporal stability commensurate with the quality of

the calibrations are accepted for cali- bration. Calibration tests usually in- clude five different flow rates, although additional rates can be in- cluded on request. At each flow rate,

five determinations of meter indication and flow rate are made; the

entire test sequence is repeated —

usually on the following day.

Meter systems submitted should

have conventional connections, either

A/N flare fittings up to 2-in (5 cm)

nominal diameters, or National Pipe

Thread fittings up to 3-in (7.6 cm)

nominal diameter. Larger meters

must terminate with ASA 150-lb steel flanges, or grooved-end steel pipe

compatible with Victaulic couplings

(for water meters), or with adapters

thereto. For air flow systems with

flow rates above 100 ftVmin (2.8 mV

min), flanges must terminate with

ASA 300-lb steel flanges except for laminar element flowmeters operated

near ambient pressure levels. Connections other than these should not be

submitted unless special arrange- ments have been made in advance.

NIST maintains a range of facilities that are capable of serving as national

standards for fluid flow rate measure- ments for a wide range of fluid and

flow conditions.

Small Air Flow Facilities: Calibration

of devices in this laboratory covers

the air flow range up to approximately 100 standard cubic feet per

minute (SCFM) [2.8 standard cubic

meters per minute (SCCM]. The mass

flow rate of gas passing through a metering device during its calibration

is determined from pressure, temperature, volume, and transit time measurement of the displaced volumes of

gas. Two types of displacers are used,

bell gasometers and mercury-sealed

piston/cylinder provers. Determination of the displaced volume in either case is based on diameter and stroke

measurement. Currently, these are done using fixed switching positions

of optical or mechanical switch mechanisms for eight provers with volumes

ranging from 3 x 10"^ m^ to 0.566 m^

Measurements of pressure are made

using manometers and barometers.

Temperature measurements are made

using contacting techniques, i.e., ther- mocouples, thermistors, etc. The

overall uncertainty for the air flow

rate measurements is quoted to be

±0.25 percent; this is determined by

summing a three standard deviation

uncertainty of ±0.15 percent, and an

estimated systematic error of

31
0.1 percent. Details on these facilities are given by Benson et al.

Large Air Flow Facility: The large air flow facility consists of a compressor

as the pressure source, a dryer, set- tling chamber, meter runs (2- to 8- inch pipe sizes) (50-203 mm), and a

collection tank. Flow rates from 35 to 3000 SCFM (0.99 to 84.95 m' min)

are attainable at pressures up to 90

psig (620 KPa). Calibration measure- ments are based upon the use of a set of working standards, which are flow

nozzles operated under critical conditions, i.e., at sonic velocity in the

throat of the nozzle. These provide an extremely stable flow which is not

influenced by variations in downstream pressure and temperature conditions. Determination of the mass

flow rate through these nozzles is based upon measured discharge coefficients. Measurement of the dis- charge coefficient for each nozzle over the range of throat Reynolds

numbers used is performed by divert- ing the gas flowing through the nozzle

into the collection tank of the facility for a measured period of time. Once

the gas has been collected, a PVT

measurement is used to determine

the mass of gas in the tank. This

value of the mass of gas is used with

the diversion time to compute the av- erage mass flow rate through the

nozzle. The overall uncertainty

quoted for this flow system is ±0.25

percent. This value is obtained as described above for the Small Air Flow

Facilities. Water Flow Facility: The water flow

facility consists of reservoir, pumps,

meter runs, and weigh tanks necessary to make primary flow measurements. Pipeline sizes up to 16 inches

(406 mm) in diameter are available. The system operates as a constant flow rate facility using bypass and meter-run control valves to control the

pressure and flow rate in the system.

Diversion into the weigh tanks is ac- complished with pneumatically driven

diverter valves fitted to each of the

four weighing systems used. The overall uncertainty for the water flow facility is quoted to be ±0.13 percent;

this is determined by summing a three standard deviation uncertainty

of ±0.03 percent, and an estimated

systematic error of ±0.1 percent.

Hydrocarbon Flow Facilities: These

facilities have the ability to handle

a variety of hydrocarbon liquids. The

majority of the calibration requests

pertain to the use of a surrogate

liquid for JP-4 and JP-5 jet fuels as the liquid used in the calibration. Both volumetric and gravimetric

systems are used to calibrate flow- meters. The flow rate range of this laboratory extends from 0.01 to ap- proximately 400 gallons per minute

(3.5-10"^ to 1.5 mVmin). A variety

of meter types are calibrated, al- though turbine meters predominate.

The overall uncertainty quoted for these systems is as given above for the Water Flow Facility.

Special Tests for Liquid and Gas

Flow Rates (18050S)

Special tests for liquid and gas flow

rates can be arranged. Examples can

include "in-situ" calibration of flowmeters, proving other fluid measure- ment systems, etc. Tests to establish

and maintain more realistic traceability for flow measurement laboratories can be designed for specific situations. Details can be obtained and

arrangements made through the technical contacts listed at the beginning

of this section.

32
1801001 8050S

References — Flow Rate Measurements

NBS Primary Calibration Facilities for Air Flow Rate, Air Speed, and

Slurry Flow, K. R. Benson, N. E. Mease, G. Kulin, and G. E. Mattingly, Proc. Intl. Flow Meas.

Symp., Washington, D.C., Nov.

1986, Amer. Gas Assoc., Arlington,

VA.

Gas Flow Measurement: Calibration

Facilities and Fluid Metering

Traceability at the National Bureau

of Standards, G. E. Mattingly, Proc. Inst, for Gas Tech. Conf. on Energy Meas., Chicago, IL (May

1985) Fundamentals of Flow Measurements, J. P. DeCarlo, Instr. Soc. of America, Research Triangle

Park, NC (1984).

Flow Measurement Engineering

Handbook, R. W. Miller, McGrawHill, New York (Jan. 1983).

A Laboratory Study of Turbine Meter

Uncertainty, G. E. Mattingly, P. E. Pontius, H. H. Allion, and

E. F. Moore, Natl. Bur. Stand.

(U.S.), Spec. Publ. 484 (Oct. 1977).

The National Measurement System

for Fluid Flow, W. C. Haight,

P. S. Klebanoff, F. W. Ruegg, and

G. Kulin, Natl. Bur. Stand. (U.S.),

NBSIR 75-930 (Aug. 1976).

Introduction to Liquid Flow Metering

and Calibration of Liquid Flowmeters, L. O. Olsen, Natl. Bur. Stand.

(U.S.), Tech. Note 831 (June 1974).

Flow Measurement: Procedures and

Facilities at the National Bureau of

Standards, F. W. Ruegg and M. R. Shafer (Proc. Symp. Flow Measurement, San Francisco, CA, Jan. 19-

22, 1970). Chapter in ASHRAE

(Amer. Soc. Heat Refrig. AirCond. Eng.), Bull. Flow Measurement Part 1, SF70-7, 1 (1972).

Gas Flow Measurement by Collection

Time and Density in a Constant Volume, L. Olsen and

G. Baumgarten, Symposium on

Flow, Its Measurement and Control

in Science and Industry, ISA, 1, Part 3, 1287 (1972).

Evaluation of a Low Flow Generator

and Calibrator as a Flow Measurement Standard, G. Baumgarten,

Natl. Bur. Stand. (U.S.), Tech. Report 10921 (1972).

Practical Considerations for Gas Flow

Measurement, M. R. Shafer, Jr., and D. W. Baker, Proc. 3rd Annual

Prec. Meas. Assoc. Metrology

Conf., Natl. Bur. Stand., Gaithersburg, MD, June 17-18, 1970, 1, 187

Prec. Meas. Assoc., Burbank, CA

(1970).

Liquid-Flowmeter Calibration Techniques, M. R. Shafer and F. W.

Ruegg, ASME Paper No. 57-A-70.

Performance Characteristics of Turbine Flowmeters, M. R. Shafer,

ASME Paper No. 61-WA-25.

33
18800S

B. Flow Measurements at Cryogenic

Temperature

Technical Contacts:

James A. Brennan

Tel: 303/497-3611

Kathy Hillen Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 832.02, National Institute of Stan- dards and Technology, 325 Broadway, Boulder, CO

80303-3328

NBS-CGA Cryogenic Flow Measurement Program, J. A. Brennan,

R. W. Stokes, C. H. Kneebone, and

D. B. Mann (Proc. ISA Intl. Instru- ment. Automation Conf. and Exhibit, New York, NY, Oct. 28-31,

1974), Paper in Adv. in Instrument.

29, 612.1 (Instr. Soc. of America,

Pittsburgh, PA, 1974).

Cryogenic Flow Research Facility

Provisional Accuracy Statement,

J. W. Dean, J. A. Brennan, D. B. Mann, and C. H. Kneebone, Natl. Bur. Stand. (U.S.), Tech. Note 606

(July 1971).

Test No. Items 18800S Special Tests of Cryogenic Liquid Flow

Special Tests of Cryogenic Liquid

Flow (18800S)

Limited measurement services are provided for cryogenic liquid flow. Mass flow measurements are per- formed using liquid nitrogen flow

rates of 1 to 10 Kg/s. Uncertainty

within this flow range is 0.18 percent.

For volumetric flow measurement the

uncertainty in fluid density must also be included. Lower flow rates are

possible but at increased uncertainty.

References — Flow Measurements at Cryogenic Temperature

Progress Report on Cryogenic

Flowmetering at the National

Bureau of Standards, J. A.

Brennan, J. F. LaBreque, and C. H. Kneebone, Proc. 1st Biennial

Symp. Instrumentation in the Cryogenic Industry, Houston, TX, Oct.

11-14, 1976, 1, 621, Instr. Soc. of

America, Pittsburgh, PA (1976).

34
19010C-19040S

Norman E. J. Michael George E. Mease Hall Mattingly

Tel: 301/975-5959 Tel: 301/975-5947 Tel: 301/975-5939

Mailing Address: 105 Fluid Mechanics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 19010C Pitot-Static Tubes 1.3 to 67 m/s (3 to 150 mph)

19020C Low Airspeed Instruments

0.76 to 10.2 m/s (15 to 2,000 fpm)

19030S Meteorological Airspeed Instrumentation

1.3 to 67 m/s (3 to 150 mph)

19040S Special Tests of Airspeed Instruments

Airspeed Instruments

(19010C-19040S)

Calibration of airspeed measuring

devices is performed in one of two

special wind tunnels (see Benson et

al.). The pressure differential measured from ellipsoidal-nosed Pitotstatic tubes provides the basis of

airspeed measurement in these facilities. Pitot-static tubes and meteorological instruments are calibrated in the NIST Dual Test Section Wind

Tunnel. Low velocity airspeed measurements are based upon laser ve- locimeter measurements in the NIST

Low Velocity Airflow Facility. Cali- bration of the laser velocimeter is done using the Pitot-static tube at velocities which produce a sufficiently

large pressure differential in the tube

that the uncertainty in the pressure

measurement does not propagate a

large error into the velocity determination. Extension of the laser ve- locimeter to the low velocity region,

where the Pitot-static tube has large

measurement errors due to the inability to measure accurately the ex- tremely small pressure differentials produced by the Pitot-static tube, al- lows considerably improved measure- ment uncertainty. Air density values

in the tunnels are computed from

pressure, temperature, and humidity

measurements in the settling chamber

of the tunnel. Total uncertainty levels for the

range of airspeed currently offered

are shown in Figure 3.

Figure 3. Total Uncertainty for the NIST Airspeed Measurements Capability.

100

<

' '

1 ""1 ' 1 1 1

1 1 M| 1

,

\Dual Test Section \Wind Tunnel

1

1

1 1 M|

i.ow Velocity Facility —

< ' 1 < o'l < >

<

»

. \ . . .A

MILES PER HOUR

I . ^ ..I : ,I , , mI , I I

I I I I l l , ,_U

0.05 0.1 0.5 1.0 5 10 50 METERS /SECOND

Special tests of airspeed instru- ments can be arranged. Examples in- clude "in-situ" calibration of airspeed

instrumentation, proving other air- speed measurement systems, and tests where appropriate scaling will allow

the results to be applicable to fluids other than air. Details can be obtained and arrangements made

through the technical contacts cited

at the beginning of this section.

35
References— Airspeed Measurements

NBS Primary Calibration Facilities for Air Flow Rate, Airspeed, and

Slurry Flow, K. R. Benson, N. E. Mease, G. Kulin, and G. E.

Mattingly, Proc. Intl. Flow Symp.,

Washington, D.C. (Nov. 1986),

Amer. Gas Assoc., Arlington, VA.

Experimental Investigation of Drag

on a Compliant Surface, J. M.

McMichael, P. S. Klebanoff, and

N. E. Mease, Part of chapter 7 in Viscous Flow Drag Reduction,

Gary R. Hough, Ed., Progress in Astronautics and Aeronautics, 72

(1980).

Low-Velocity Performance of

Anemometers, L. P. Purtell, Natl. Bur. Stand. (U.S.), NBSIR 79-1759

(May 1979).

A Low-Velocity Airflow Calibration

and Research Facility, L. P. Purtell and P. S. Klebanoff, Natl. Bur.

Stand. (U.S.), Tech. Note 989

(Mar. 1979).

Low-Velocity Performance of a Magnetic Pick-up Vane Anemometer,

L. P. Purtell, Natl. Bur. Stand.

(U.S.), NBSIR 79-1566 (Dec.

1978).

Low-Velocity Performance of a Ball Bearing Vane Anemometer, L. P. Purtell, Natl. Bur. Stand. (U.S.),

NBSIR 78-1485 (June 1978).

36
22010C-22180M

Mass Standards

Technical Contact:

Jerry G. Keller

Tel: 301/975-4218

Mailing Address: A117 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, B33 Metrology, Gaithersburg, MD 20899-0001

Note: For weights larger than 50 lb (30 kg), contact J. G.

Keller prior to shipment.

Test No. Items 22010C

22020C

22030C

22040C

22060C

22080C

22100C

22110C

22130C

22140C

22150C

22170S 22180M

Weight Set (1 mg to 100 g)

Weight Set (1 mg to 1 kg)

Weight Set (2 to 30 kg)

Single Weights (1 mg to 1 kg)

Single Weights (2 kg to 30 kg)

Single Weights (>30 kg to 1200 kg, 2 double

substitution weighings)

Single Weights (> 1200 kg to 30,000 kg)

Single Weights (>30 kg to 1200 kg, calibrated in a weighing design)

Single Weights for Deadweight Pressure Testers

(13 lb-50 lb) Single Weights for Deadweight Pressure Testers (>50 lb) Single Weights for Deadweight Pressure Testers (<131b)

Special Mass Measurement Services Measurement Assurance Program for Mass

Mass (22010C-22110C)

NIST maintains the national stan- dards for mass in the form of the

prototype kilograms (K4 and K20)

and provides services to support the

parts of the national measurement

system that rely directly or indirectly on mass measurements. These ser- vices include the calibration of suit- able weight sets. A calibration

consists of establishing a mass value

and the appropriate uncertainty for that value for each weight that has

been designated to be a reference

standard. It is desirable, but not necessary, that a weight meet the adjustment tolerances established for Classes A, B, M, S, or S-1 prior to submission. Weights are available

from manufacturers, many of whom

can directly furnish documentation

suitable for meeting quality assurance

contracts and requirements.

For periodic recalibrations of refer- ence mass standards, the user need measure only differences between

weights or groups of weights within a

set and compare them with computed

differences. As long as the agreement

is within allowable limits, the values can be considered constant within the

precision of the comparison process. Mass standards submitted to NIST

for recalibration frequently are tested

in this manner. If these tests indicate

that no significant changes have oc- curred, a continuation report so stat- ing and referring to the previous

NIST Report of Calibration will be is- sued.

NIST calibrates individual weights

or sets in the range of 1 mg to 30 kg

or 1 lb to 50 lb in decimal subdivisions. If the weights are designated as reference standards, they must be of

design, material, and surface finish comparable to present Classes A, B,

M, S, or S-1. These include ASTM

Type I and II, grade S and O, and

OIML El, E2, and Fl. NIST also cal- ibrates large mass standards (60 to 60,000 lbs) if the design, material,

and surface finish are compatible with

the intended usage. For these large

37
22010C-22180M

mass standards, an adjustment with

reference to a nominal or desired

value can be included as a part of the

calibration procedure.

The values of true mass (and an

apparent mass correction) included in the report will be determined by us- ing computed volumes based on the

manufacturer's statement of density

of the material, or on the density

computed from measured volumes,

or, in the absence of this information, on estimated density values. However,

1-kg mass standards fabricated from

stainless steel and of one-piece construction will have their density deter- mined as part of a "first-time"

calibration at NIST. The apparent mass corrections are computed for 20 °C with reference to Normal Brass

(density 8.4 g/cm' at 0 °C and volume

coefficient of expansion 0.000054/°C)

and to stainless steel (density 8.0 g/

cm^ at 20 °C) in a conventional air density of 1.2 mg/cm^ Apparent mass

corrections to any other basis can be

furnished if requested. Typical uncertainties range from 50 parts per bil- lion at 1 kilogramg up to 500 parts

per million at one milligram and 1 part per million for weights from 2 to 30 kilograms. Figure 4 shows the

NIST precision of weighing for mass

standards over the range 10 ~* to 10'' kilograms.

Figure 4. NIST Precision of Weighing for Mass

Standards Ranging from 10'^ to 10" Kilograms

' Balances & Scales - .000001 %

^ Elastic Devices . • * . -.0001%

i AA -.01%

- 1 %

10"'° 10"^ 10~M0"* 10"' 1 10' 10" 10' Load in Kilograms

D) CO a

Q)c

o

10^

10'

Q c

3> 10'

Single Weights for Deadweight

Pressure Testers (22130C-22150C)

Weights less than six (6) pounds are determined by comparing them with

calibrated built-in-weights of appropriate analytical balances by the double substitution method. Weights

larger than six (6) pounds are compared to discrete standards by the

method of double transposition or double substitution weighing.

Special Mass Measurement Services

(22170S)

For tests not covered by the previous

descriptions, the NIST technical contact cited at the beginning of this section should be consulted to determine whether a test can be per- formed and to negotiate a price for the test. Measurement Assurance Program for Mass (22180M)

This service is most appropriate for primary calibration laboratories. Total

uncertainties ranging from a few parts

in 10^ to a few parts in 10' for

1 kg can be obtained. Unlike most

other NIST MAP services, the Mass

MAP service does not involve the use

of a NIST-owned transport standard

that is shipped to participants for measurement. The transfer standards

in the mass MAP are a set of mass

standards owned by the participant

and sent to NIST for calibration. These standards are referred to as the starting standards. In addition to the starting standards, the mass MAP

participant must also furnish a set of

much smaller weights called "sensitivity weights." The choice of both the

starting standards and the sensitivity

weights will depend on the particular mass range of interest to the participant; NIST staff can provide advice

regarding suitable starting standards

and sensitivity weights for a particular

range of mass weighings. In addition

to the starting standards and the sensitivity weights, the participating facility should have a working set of

weights known as the "test set" and a

set of weights to be used as check

38
22010C-22180M

standards. This set usually consists of

weights in the range 1 to 1000 g. This service, like other NIST MAP

services, samples the participant's

measurement process and establishes

its uncertainty. Once the participant

has become well-established in the

Mass MAP, two options are possible:

(1) NIST personnel do all of the

data analysis and record keeping for the participant and provide periodic

reports on the uncertainty of the participant's mass measurements.

(2) The participant keeps all records and calculates the uncertainties of his measurements using NIST

methods and computer codes.

The implementation of the Mass

Measurement Assurance Program in

its most complete form typically pro- ceeds in four distinct phases, which

may be abbreviated somewhat if the

participant already has a suitable mass measurement quality control

system.

Phase I: Each new participant completes a questionnaire on equipment

and facilities and receives a written

description of the NIST process, methods and procedure to be used, an introduction to the interpretation

of results, and information on the use

of these results in measurement decisions. At the participating laboratory,

the suitability of the weighing equipment is verified, the starting stan- dards selected or procured, and if the

procedures are entirely new, operators are trained. The starting stan- dards and sensitivity weights are sent

to NIST for calibration. If the starting

standards have a prior NIST calibra- tion history, those data are reviewed,

and if satisfactory, they are considered, along with the data from the more recent determinations, in arriv- ing at assigned values for the starting

standards. NIST will recommend a weighing design to be used for cali- brating the test weight. This weighing

design prescribes the set of observations for intercomparing the test weights with known weights. NIST

will also supply data sheets that are used throughout the first three phases

of the program for recording data

taken using the design. The objective

of the first phase is to ensure that the new participant is familiar with good

laboratory practices for high precision

weighing. If the participating laboratory has an established mass measure- ment capability and an existing

quality control procedure for mass

measurements. Phase I is abbreviated

considerably.

Phase II: The starting standards and

sensitivity weights are returned to the

participant and, following the prescribed procedures, measurements are made over a period of time by the

participant to verify that a state of

statistical control exists. The data

sheets are sent to NIST for review,

comments, and processing after each

measurement. If there are unanticipated problems, or the procedure has

not been followed exactly, more measurements may be required. After

three or more successful calibrations

in the user's facility, NIST analyzes

the data to determine the values of

the check standards.

Phase III: A comprehensive report is issued by NIST that contains a review

of the actions and decisions in each

of the phases, control charts for the

check standards to be used in the

participant's facility, and a comparison of the values assigned to the

starting standards by NIST and by the

participant. It is assumed at this point

that the participating facility is now

ready to extend the operation of the

MAP to its regular workload.

Phase IV: Having thus established

measurement comparability, the MAP

user can then, in principle, operate

independently of NIST. As long as there is no indication of a loss of

statistical control of the process, no

further checking with NIST should be

necessary. Most participants request a recheck of the starting standards ev- ery few years to ensure that no undetected long-term drift has taken

place.

39
22010C-22180M

For work that differs from the

items normally calibrated by the participant, NIST can provide consulting

help and assistance necessary to ac- commodate a greater range of

weights, calibrate pound standards,

and extend pound standards to large

weights normally associated with

force measurement. Although the

usual Mass MAP service uses two one kilogram masses as the starting

standards, the program is sufficiently

flexible that the same methods can be

used with other mass values.

References — Mass Standards

New Assignment of Mass Values and

Uncertainties to NIST Working

Standards, R. S. Davis, .T. Res.

Natl. Inst. Stand. Technol., 95, No.

1, 79 (Jan.-Feb. 1990).

NIST Measurement Services: Mass

Calibrations, R. S. Davis, Natl.

Inst. Stand. Technol. Spec. Publ.

250-31 (Jan. 1989).

A Primer for Mass Metrology, K. B. Jaeger and R. S. Davis, Natl. Bur. Stand. (U.S.), Spec. Publ. 700-1

(Nov. 1984).

Air Buoyancy Correction in High-Accuracy Weighing on Analytical Balances, R. M. Schoonover and

F. E. Jones, Anal. Chem., 53, No.

6, 900 (May 1981).

National Bureau of Standards Mass

Calibration Computer Software, R. N. Varner and R. C. Raybold,

Natl. Bur. Stand. (U.S.), Tech.

Note 1127 (July 1980).

Quick and Accurate Density Determination of Laboratory Weights, R. M. Schoonover and R. S. Davis,

Proceedings of the 8th Conference

of IMEKO, Krakow, Poland (1980).

Precision Laboratory Standards of

Mass and Laboratory Weights. A

reprint of NBS Circular 547, Section 1, T. W. Lashof and L. B. Macurdy, August 1954, Natl. Bur.

Stand. (U.S.), NBSIR 78-1476 (Oct.

1978).

The National Measurement System

for Mass, Volume, and Density,

P. E. Pontius, J. R. Whetstone, and

J. A. Simpson, Natl. Bur. Stand.

(U.S.), NBSIR 75-928 (May 1978).

Direct Determination of Air Density

in a Balance through Artifacts

Characterized in an Evacuated

Weighing Chamber, W. F. Koch, R.

S. Davis, and V. E. Bower, J. Res.

Natl. Bur. Stand. (U.S.), 83, No. 5, 407 (Sept.-Oct. 1978).

The Air Density Equation and the

Transfer of the Mass Unit, F. E. Jones, J. Res. Natl. Bur. Stand.

(U.S.), 83, No. 5, 419 (Sept.-Oct.

1978).

Designs for the Calibration of Stan- dards of Mass, J. M. Cameron,

M.C. Croarkin, and R. C. Raybold,

Natl. Bur. Stand. (U.S.), Tech.

Note 952 (June 1977).

The Air Density Equation and the

Transfer of the Mass Unit, F. E. Jones, Natl. Bur. Stand. (U.S.),

NBSIR 77-1278 (July 1977).

Measurement Assurance, J. M.

Cameron, Natl. Bur. Stand. (U.S.),

NBSIR 77-1240 (1977).

Surveillance Test Procedures, H. W.

Aimer, Natl. Bur. Stand. (U.S.),

NBSIR 76-999 (Feb. 1976).

Mass and Mass Values, P. E. Pontius,

Natl. Bur. Stand. (U.S.), Monogr.

133 (Jan. 1974).

Weight Cleaning Procedures, H. E. Aimer, Natl. Bur. Stand. (U.S.),

NBSIR 74-443 (Nov. 1973).

On Uncertainty in Mass Measurement, J. R. Donaldson, Natl. Bur.

Stand. (U.S.), NBSIR 73-151 (Mar.

1973).

Method of Calibrating Weights for Piston Gages, H. E. Aimer, Natl. Bur. Stand. (U.S.), Tech. Note 577

(May 1971).

Realistic Uncertainties and the Mass

Measurement Process, P. E. Pontius and J. M. Cameron, Natl. Bur. Stand. (U.S.), Monogr. 103

(Aug. 1967).

Introduction to Intercomparison

Methods in Mass Measurement,

H. E. Aimer, Natl. Bur. Stand.

(U.S.), Report 9487 (Feb. 1967).

Measurement Philosophy of the Pilot Program for Mass Calibration,

P. E. Pontius, Natl. Bur. Stand.

(U.S.), Tech. Note 288 (May 1966).

40
23010C-23260S

E

Force Measurements

Technical Contacts:

Simone L. Robert W.

Yaniv Peterson

Tel: 301/975-6655 Tel: 301/975-6649

Mailing Address: 221 Engineering Mechanics, National

Institute of Standards and Technology, Gaithersburg, MD

20899-0001

Sliipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Engineering

Mechanics Building, Room 123, Gaithersburg, MD 20899-

0001

Test No. Items 23010C Force Transducers (to 25,000 Ibf, 1 mode)

23020C Extra observation

23030C Additional bridges

23040C Force Transducers (to 25,000 Ibf, 2 modes)

23050C Extra observation

23060C Additional bridges

23070C Force Transducers (25,001 to 112,000 Ibf, 1 mode)

23080C Extra observation

23090C Additional bridges

23100C Force Transducers (25,001 to 112,000 Ibf, 2 modes)

231 IOC Extra observation

23120C Additional bridges

23130C Force Transducers (112,001 to 300,000 Ibf, 1 mode)

23140C Extra observation

23150C Additional bridges

23160C Force Transducers (112,001 to 300,000 Ibf, 2 modes)

23170C Extra observation

23180C Additional bridges

23190C Force Transducers (300,001 to 1,000,000 Ibf, 1 mode)

23200C Extra observation

23210C Additional bridges

23220C Force Transducers (300,001 to 1,000,000 Ibf, 2 modes)

23230C Extra observation

23240C Additional bridges

23250C Force Transducers (over 1,000,000 Ibf) 23260S Special Tests of Force Transducers

Force Transducers (23010C-23250C)

NIST provides calibration services for force measuring devices by applying

known forces, either tension or compression, to the elastic device and

recording the sensed deformation.

Most of the devices calibrated are ei- ther proving rings or load cells. The

deformation of proving rings is usually measured by means of a micrometer screw and vibrating reed, which

are an integral part of the device.

Load cells, which utilize strain gauge

bridges, produce an electrical output

that is related to the applied force. The calibration report describes the

relationship between the applied

force and the measured deformation,

either in electrical or mechanical

units. A load cell can be calibrated

using (1) a readout device furnished

by the customer, in which case the

load cell and the readout device are

calibrated as a system, and the cali- bration is valid only when the load

cell and the readout device are used

together; or (2) instrumentation fur- nished by NIST, in which case data

are reported in terms of the ratio of

the output voltage to the DC excita- tion voltage {mVIW). In the latter case, the customer must possess the necessary electrical instrumentation

and expertise to utilize the calibration

results. Tension or compression calibra- tions in the range of 100 pounds-force

(Ibf) to 1,000,000 Ibf are performed

using deadweight machines. NIST has

six such deadweight machines with

maximum capacities of 500; 6,100;

25,300; 112,000; 300,000; and

1,000,000 Ibf. The four larger machines allow the force applied to the

unit being calibrated to be incre- mented or decremented without having to return to zero load between

41
force applications. When using the

two smaller machines it is necessary

to go to zero load before the load is changed. For all six deadweight machines, the estimated uncertainty of

the vertical component of the applied

force is 20 ppm.

Comparison calibrations in the

range of 1,000,000 Ibf to 12,000,000

Ibf in compression only are per- formed in a universal testing machine.

In this case, the system being cali- brated is loaded in series with load

cells that have been previously cali- brated in a deadweight machine.

Special Tests of Force Transducers

(23260S)

Temperature sensitivity, pressure sensitivity and creep tests of force trans- ducers are measured. The ranges of

test parameters and environmental

conditions may be limited by the

characteristics of the force transducer

and the availability of special test fix- tures. These special tests should be

discussed with the designated NIST

technical contact before the work is scheduled.

References — Force Measurements

Interlaboratory Comparison of Force

Calibrations Using ASTM Method

E74-74, R. W. Peterson, L. Jenkins,

and R. A. Mitchell, Natl. Bur.

Stand. (U.S.), Tech. Note 1211

(Apr. 1985).

Metrological Regulations for Load

Cells, OIML International Recommendation No. 60, Intl. Org. for Legal Metrol., Paris (Oct. 1984).

Progress in Force Measurement at NBS, R. A. Mitchell, Proc. 10th

Conf. IMEKO TC-3 on Measurement of Force and Mass, Kobe,

Japan (Sept. 1984).

Inherent Problems in Force Measurements, P. E. Pontius and R. A.

Mitchell, Exper. Mech., 22, No. 3 (Mar. 1982).

Force Sensor-Machine Interaction, R. A. Mitchell and P. E. Pontius,

Proceedings of the 27th International Instrumentation Symposium

(ISA), Indianapolis, IN, Instrumentation in the Aerospace Industry,

27, 225 (1981).

Characterizing the Creep Response of

Load Cells, R. A. Mitchell and

S. M. Baker, VDI-Berichte 312, 43

(1978).

Interlaboratory Comparison of Force

Calibrations Using ASTM Method

E74-74, Phase I, R. W. Peterson

and R. L. Bloss, Natl. Bur. Stand.

(U.S.), NBSIR 76-1145 (Aug.

1976).

A Study of the National Force Measurement System, D. E. Marlowe,

Natl. Bur. Stand. (U.S.), NBSIR

75-929 (June 1975).

Universal Testing Machine of 12- Million-lbf Capacity at the National

Bureau of Standards, A. F. Kirstein, Natl. Bur. Stand. (U.S.),

Spec. Publ. 355 (Sept. 1971).

Studies of Calibration Procedures for Load Cells and Proving Rings as Weighing Devices, G. B. Anderson

and R. C. Raybold, Natl. Bur.

Stand. (U.S.), Tech. Note 436 (Jan.

1969).

Gravity Measurements and the Stan- dards Laboratory, D. R. Tate, Natl. Bur. Stand. (U.S.), Tech. Note 491

(Aug. 1969).

Uncertainties Associated with Proving

Ring Calibration, T. E. Hockersmith and H. H. Ku, Preprint No. 12.3-2-64 ISA Conference, Instr. Soc. of America, Res.

Triangle Park, NC (Oct. 1964).

42
240iOG-24060S

Vibration Measurements

Technical Contacts:

Beverly F. Donald C. Myroslav R. Payne Robinson Serbyn

Tel: 301/975-6639 Tel: 301/975-6643 Tel: 301/975-6646

Mailing Address: A149 Sound, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items Freq. Range Peak Accel. Uncer. in %

24010C Pickup

Sensitivity

2 to 160 Hz 0.2 to 2 g ±1 to ±2

24020C Pickup

Sensitivity

10 to 3500 Hz 2 to 10 g ±1 to ±2

24030C Pickup

Sensitivity

10 Hz to 10 kHz 2 to 10 g ±1 to ±2

24040S Shock Measurement

10 Hz to 10 kHz 50 to 5000 g ±3 to ±5

24050S Pickup

Sensitivity

3 to 20 kHz 4 to 200

g

±1 to ±3

24060S Special Vibration Tests, by Prcarrangcmcnt

Pickup Sensitivity (24010C-24030C)

NIST calibrations of vibration exciters and pickups are performed by comparison with the response characteristics of NIST standards or by absolute

measurements. A calibration consists

of measuring the transfer function of

the instrument, usually referred to as the sensitivity. For a pickup it is the

ratio of the electrical output to a mechanical input. The magnitude of the

latter is set in accordance with the

calibration method, the type of vibration exciter, and the frequency of vi- bration. The magnitude of the output

depends, of course, on the nature of

the test device. In the case of an ac- celerometer with signal conditioner,

the practice has been to express the

output in millivolts, and the input in units of gn, the standard acceleration

of free fall.

The acceleration sensitivity is then

given in mV/g. For charge-output

devices without signal conditioners,

the acceleration sensitivity is stated in picocoulombs per g (pC/g). All measurements are performed at 23 ±3 °C

and 50± 10 percent r.h. The calibration of an accelerometer

is reported in tabular form as the

sensitivity magnitude at a set of dis- crete frequencies; the phase component can be furnished on request, at additional cost. The NIST vibration standards are

periodically calibrated by reciprocity

and/or interferometric techniques,

two independent and absolute methods. The use of these standards in the

calibration of stable transducers fur- nishes calibration data with a typical

uncertainty of one to two percent depending on the frequency range.

Special Shock Measurement Services

(24040S)

The shock facility provides a comparison calibration of accelerometers by

subjecting them to half-sinewave

pulses with peak amplitudes of 50 to 5000 g and pulse widths from 0.2 to 40 milliseconds. Both time and fre- quency domain measurements can be

performed.

Special Tests of Pickup Sensitivity

(24050S)

This test measures the pickup sensitivity by the fringe-disappearance

method, using an automated Michelson interferometer. As presently configured, the system operates between

3 kHz and 20 kHz. The method re- quires precise setting of vibration amplitude to 121.10 nm; consequently,

the acceleration amplitude in the

stated frequency range increases from

about 4 to 200 g.

Special Vibration Tests (24060S)

Calibration of vibration and shock

measuring instruments to specifica- tions different from those above as

43
well as other measurements can be

performed by prearrangement. For

example, a comparison calibration for frequencies less than 2 Hz or greater

than 10 kHz can be performed on re- quest. Consult with the technical contacts cited at the beginning of this section.

References —Vibration Measurements

An Application of Parameter Estimation Theory in Low Frequency

Accelerometers, B. F. Payne and

M. R. Serbyn, 14th Transducer

Workshop, Telemetry Group,

Range Commanders Council, Colorado Springs, CO (June 1987).

A Description of NBS Calibration

Services in Mechanical Vibration

and Shock, D. C. Robinson, M. R.

Serbyn, and B. F. Payne, Natl. Bur. Stand. (U.S.), Tech. Note 1232

(Feb. 1987).

An Automated Fringe Counting

Laser Interferometer for Low Fre- quency Vibration Measurements,

B. F. Payne, Proc. ISA Symp.,

Seattle, WA (May 1986).

Automation of Vibration Testing at the National Bureau of Standards,

B. F. Payne, Proc. 30th Tech.

Meeting, Inst, of Environ. Sciences

(May 1984).

An Automated System for the Measurement of Pickup Sensitivity, B. F. Payne and M. R. Serbyn,

Proc. Natl. Conf. Stand. Lab.

Ann. Workshop and Symp.

II-11.1-II-11.22 (July 1983).

The Application of Back-to-Back

Accelerometers to Precision Vibration Measurements, B. F. Payne,

J. Res. Natl. Bur. Stand. (U.S.), 88,

No. 3, 171 (May-June 1983).

A Real-Time Active Vibration Controller, M. R. Serbyn and W. B. Penzes, ISA Transactions, 21, No.

3, 55 (1982).

Development of a Low-Frequency-Vibration Calibration System, R. S. Koyanagi, Exp. Mech., 15, 443

(Nov. 1975).

Shock Calibration of Accelerometers,

C. Federman, W. Walston, and J. Ramboz, Minutes of the 8th Trans- ducer Workshop: Telemetry

Group, Inter-Range Instrumentation Group, Range Commanders

Council, Wright-Patterson AFB,

OH (Apr. 1975).

Piezoelectric Shakers for WideFrequency Calibration of Vibration

Pickups, E. Jones, B. Yelon, and

S. Edelman, J. Acoust. Soc. Am.,

46, No. 6, 1556 (June 1969).

Improved Transfer Standard for Vibration Pickups, E. Jones, D. Lee,

and S. Edelman, J. Acoust. Soc. Am., 41, No. 2, 354 (Feb. 1967).

Electrodynamic Vibration Standard

with a Ceramic Moving Element,

T. Dimoff, J. Acoust. Soc. Am., 40,

No. 3, 671 (Sept. 1966).

Calibration of Vibration Pickups at Large Amplitudes, E. Jones, S. Edelman, and K. S. Sizemore,

J. Acoust. Soc. Am., 33, No. 11, 1462 (Nov. 1961).

Calibration of Vibration Pickups by

the Reciprocity Method, S. Levy

and R. R. Bouche, J. Res. Natl. Bur. Stand. (U.S.), 57, No. 4, 227

(Oct. 1956).

44
250 IOCG. Acoustic Measurements

Technical Contacts:

victor Nedzelnitsky

Tel: 301/975-6638

David J. Evans

Tel: 301/975-6637

Mailing Address: A147 Sound, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 25010C Pressure Response: WE Type 640AA microphones or equivalent (e.g., Tokyo Riko Type ECL MR103,

Bruel & Kjaer Type 4160, Bruel & Kjaer Types 4144

or 4132 with DBOlll adapter). 50 to 10,000 Hz. 25020C Pressure Response: WE Type 640AA microphones or equivalent (e.g., Tokyo Riko Type ECL MR103;

Bruel & Kjaer Type 4160; Bruel & Kjaer Types 4144

or 4132 with DBOlll adapter). 50 to 20,000 Hz. 25030C Pressure Response: Tokyo Riko Type ECL MR112,

Bruel & Kjaer Type 4134, or equivalent half-inch microphones, 50 to 10,000 Hz. 25040C Pressure Response: Tokyo Riko Type ECL MR112,

Bruel & Kjaer Type 4134, or equivalent half-inch microphones, 50 to 20,000 Hz. 25050C Free-Field Response: Tokyo Riko Type ECL MRl 12, Bruel & Kjaer Types 4133, 4134, 4165, 4166, 4180, or

equivalent half-inch microphones, 2,500 to 20,000 Hz. 25060S Special Tests of Acoustic Devices

25070S Special Tests of Earphones

Pressure and Free-Field Response of

Microphones (25010C-25050C)

Pressure calibrations (Test Nos. 2501 OC and 25020C) are performed on Type-L one-inch microphones sat- isfying the requirements of American

National Standard SI. 12-1967

(R1977), Specifications for Laboratory Standard Microphones and its impending revision. The microphones

submitted for pressure calibration

must be suitable for use with the cali- brating couplers shown in Figures 6

and 10 of the applicable American

National Standard SI. 10-1966

(R1986).

Pressure calibrations are reported

in terms of open-circuit voltage per

unit sound pressure applied uniformly

to the diaphragm. The open-circuit

voltage at the electrical terminals of a microphone may be influenced by

stray capacitance evident at these ter- minals. For Type-L microphones,

these capacitances are defined by the

geometrical configuration of the

ground shield shown in Figures 6 and

13 of SI. 10-1966 (R1986). If the

ground shield dimensions are not adhered to in making use of the re- sponse levels reported by NIST,

errors may result. Pressure calibrations of Type-L microphones exhibit

typical uncertainties of approximately

0.1 dB or less at frequencies from 50

Hz to 8 kHz, and 0.2 dB or less at frequencies from 8 kHz to 20 kHz.

Further information is contained in the references for acoustic measurements.

Since American National Standards

Institute publications SI. 10-1966

(R1986) and SI. 12-1967 (R1977) were

issued, certain types of half-inch di- ameter precision microphones have

attained widespread use. Therefore,

NIST has developed procedures (Test Nos. 25030C and 25040C) for determining the pressure response levels of

half-inch microphones by comparison

with NIST-owned Type-L standard

microphones, which in turn are cali- brated periodically by the reciprocity

technique. The technique used, pre- cautions to be observed, and uncertainties of measurement are

essentially the same as those given

above for one-inch microphones. Significantly different aspects of the pro- cedures for half-inch microphones,

such as ground shield configuration, are described in the test report. Since

several half-inch laboratory standard

microphones have been available for

45
only a relatively short time, their long-term stability has yet to be determined.

The free-field response levels of

certain Type-L microphones (e.g., Western Electric Type 640AA con- denser microphones) can be computed from pressure response levels reported by NIST. However, certain

precautions must be taken, and there

is some degradation in accuracy. Therefore, for the most demanding

free-field measurement requirements,

NIST offers a calibration service

(Test No. 25050C) for determining

the free-field response levels for half- inch microphones. The calibrations are made over the frequency range of

2.5 kHz to 20 kHz at normal "'nci- dence. Response levels (sensitivity

levels) are reported in terms of opencircuit voltage per unit sound pres- sure (in the absence of the microphone) of a plane progressive wave whose direction of propagation is nor- mal to the plane of the dia- phragm. The calibrations are per- formed in a well-characterized ane- choic chamber. A typical uncertainty

in this calibration is approximately

0.15 dB or less at each frequency

within the range of 2.5 kHz to 20

kHz. Calibrations can be performed

with or without protective grids on

the microphone. For the most precise

free-field measurements, the cus- tomer should contact the NIST staff person cited at the beginning of this section for recommendations prior to submitting the microphone to NIST

for calibration.

Special Tests of Acoustic Devices

(25060S)

Acoustical measurement services are

available by special arrangement.

These services include extended fre- quency ranges of calibration, additional data points, measurements at very low sound pressure levels, and

calibration of certain pistonphones

and acoustic calibrators. NIST has a

large general-purpose anechoic chamber available for special calibrations

requiring such a facility. The fre- quency-dependent and positiondependent acoustical performance of

this chamber, including extremely low

background noise, was carefully controlled during design and construction

and is documented in archival journal

publications.

Special Tests of Earphones (25070S)

Earphones are tested on the

NIST 9-A Coupler from 125 to 8000

Hz. Measurements of audiometer/

earphone response and linearity can be made at very low sound pressure

levels.

A NIST-owned half-inch microphone, the free-field response level of which has been determined by the

reciprocity method, is shown with a small electro- dynamic source of sound in the NIST large generalpurpose anechoic chamber.

46
2501 OC-;-25070S

References— Acoustic Measurements

Free-Field Reciprocity Calibration of

Microphones, E. D. Burnett and

V. Nedzelnitsky, J. Res. Natl. Bur. Stand. (U.S.), 92, No. 2, 129 (Mar.-

April 1987).

Traceability of Acoustical Instrument

Calibration to the National Bureau

of Standards, V. Nedzelnitsky,

Proc. INTER-NOISE 80, II, Dec.

8-10, 1980, Miami, FL, G. C. Maling, Jr., Ed., Poughkeepsie,

NY: Noise Control Foundation,

1043 (1980).

Calibration of Laboratory Condenser

Microphones, V. Nedzelnitsky,

E. D. Burnett, and W. B. Penzes,

Proceedings of the 10th Transducer

Workshop, Transducer Committee,

Telemetry Group, Range Commanders Council, Colorado Springs, CO

(June 1979).

Acoustical Properties of the National

Bureau of Standards Anechoic

Chamber, W. Koidan and G. R. Hruska, J. Acoust. Soc. Am., 64,

No. 2, 501 (Aug. 1978).

Specifications for Laboratory Stan- dard Microphones, American

National Standards Institute, SI. 12-1967 (R1977), New York,

NY.

Method for Calibration of Microphones, Amer. Natl. Stand. Inst., SI. 10-1966 (R1986), New York,

NY.

Wedge Design for the National

Bureau of Standards Anechoic

Chamber, W. Koidan, G.R. Hruska,

and M.A. Pickett, J. Acoust. Soc. Am., 52, No. 4 (Part 1), 1071

(1972).

Calibration of Standard Condenser

Microphones: Coupler Versus

Electrostatic Actuator, W. Koidan,

J. Acoust. Soc. Am., 44, No. 5, 1451 (Nov. 1968).

Calibrations of Microphones, Vibration Pickups, and Earphones, R.K.

Cook, S. Edelman, and W. Koidan,

J. Audio Eng. Soc, 13, No. 4 (Oct.

1965).

Free-Field Correction for Condenser

Microphones, W. Koidan and D.S.

Siegel, J. Acoust. Soc. Am., 36, No.

11, 2233 (Nov. 1964).

Hydrogen Retention System for Pres- sure Calibration of Microphones in Small Couplers, W. Koidan, J. Acoust. Soc. Am., 35, No. 4, 614

(Apr. 1963).

Method of Measurement of E'/I' in the Reciprocity Calibration of Condenser Microphones, W. Koidan, J. Acoust. Soc. Am., 32, No. 5, 611

(May 1960).

47
26030S-26080S

Ultrasonic Reference Block Measurements

Technical Contacts:

Gerald V. Donald G

Blessing Eitzen

Tel: 301/975-6627 Tel: 301/975-6624

Mailing Address: A147 Sound, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 26030S Special Tests of Area Amplitude Aluminum

Reference Blocks — Set of Eight Blocks 26040S Special Tests of Area Amplitude Titanium or Steel Ultrasonic Reference — Set of Eight Blocks 26050S Special Tests of Distance Amplitude Aluminum

Reference Blocks — Set of Fifteen Blocks 26060S Special Tests of Distance Amplitude Titanium or

Steel Ultrasonic Reference Blocks — Set of Fifteen Blocks 26070S Special Tests of Distance Area Amplitude (Basic Set)

Aluminum, Titanium or Steel Ultrasonic Reference Blocks — Set of Eight Blocks 26080S Special Tests of Velocity Reference Blocks

Special Tests of Aluminum Reference

Blocks (26030S, 26050S, and 26070S)

The ultrasonic response of 7075 alu- minum alloy ASTM E127 type flat- bottom-hole (FBH) reference blocks

of 0.50 inch and greater metal path

distances is determined relative to a NIST reference standard. The immersion, pulse-echo, longitudinal wave, 5

MHz quartz transducer testing system

defined in the ASTM E127 calibra- tion document is used with some pro- cedural modifications. First, in the

NIST-developed procedure, a 5-0050

block (rather than the steel balls called for in ASTM El 27) acts as the

NIST reference standard against

which all other instrument gain set- tings are defined. Second, the relative

gain settings for blocks of different

FBH sizes are determined by the ratios of their respective FBH areas

(rather than by different diameter

steel balls per ASTM E127). NIST

research shows that these procedural

differences yield improved measure- ment precision. A specific set of

NIST FBH "check standard" blocks,

acting as interim reference standards,

are then calibrated along with the customer's block. System precision

and stability over time are provided

by measurement of this set of check

standard blocks with FBH sizes of 3/ 64, 5/64, and 8/64 inch diameter.

Standard deviation data, representing

random errors associated with the

NIST system, are provided for the re- spective block and hole sizes. The

plus or minus two standard deviation

uncertainty levels range from about 3

to 12 percent of block response, depending on the block and hole sizes of the respective check standards.

A comparison of the customer's

block value to the data base of all blocks measured by NIST can be

made available. Block response fol- lowing the procedures of the ASTM

Recommended Practice E-127 can

also be determined.

Please note that for expedient turn- around of the customer's blocks, it is important that prior arrangements be

made with the technical contacts before shipping the blocks to NIST.

Special Tests of Titanium or Steel Reference Blocks (26040S, 26060S,

and 26070S)

Steel and titanium ultrasonic refer- ence blocks can be calibrated using

procedures similar to those described

in ASTM E428.

Special Tests of Velocity Reference

Blocks (26080S)

Ultrasonic transit-time measurements

of the customer's supplied blocks can be determined, from which the material velocity may be calculated.

48
26030S-26080S

References — Ultrasonic Reference

Block Measurements

Standard Practice for Fabricating and

Checking Aluminum Alloy Ultrasonic Standard Reference Blocks, E- 127-82A, in Annual Book of

ASTM Standards, Vol. 03.03,

Philadelphia, PA, Amer. Soc. for Testing and Materials (1985).

An Assessment of Ultrasonic Refer- ence Block Calibration Methodology, G. V. Blessing, Natl. Bur.

Stand. (U.S.), NBSIR 83-2710

(June 1983).

Recent Improvements to the ASTMType Ultrasonic Reference Block

System, D. J. Chwirut, Natl. Bur. Stand. (U.S.), NBSIR 79-1742

(Feb. 1979).

The Evaluation of Search Units Used

for Ultrasonic Reference Block

Calibrations, D. J. Chwirut and

G. D. Boswell, Natl. Bur. Stand.

(U.S.), NBSIR 78-1454 (Feb. 1978).

Improved Ultrasonic Standard Refer- ence Blocks, G.F. Sushinsky, D. G.

Eitzen, D. J. Chwirut, C. J. Bechtoldt, and A.W. Ruff, Natl. Bur. Stand. (U.S.), NBSIR 76-984

(Nov. 1976).

Procedures for the Calibration of

ASTM E127-Type Ultrasonic Ref- erence Blocks, D. J. Chwirut,

G. F. Sushinsky, and D. G. Eitzen,

Natl. Bur. Stand. (U.S.), Tech.

Note 924 (Sept. 1976).

49
26100C-26120S

Ultrasonic Transducer Measurements

Technical Contacts:

Steven E. Fick Donald G. Eitzen

Tel: 301/975-6629 Tel: 301/975-6624

Mailing Address: A147 Sound, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 26100C Ultrasonic Transducer Power Output; Radiation

Pressure

261 IOC Ultrasonic System Power Output; Calorimeter

26120S Special Tests of Ultrasonic Transducers

Ultrasonic Transducer Power and

Frequency (26100C-26110C)

Measurements of total ultrasonic for- ward power radiated into a water

load are offered for the purpose of

characterizing ultrasonic systems and

transducers. Ultrasonic systems are characterized by measurement of out- put under operating conditions specified by the customer. Transducers for which an amplitude-modulated con- tinuous-wave electrical input voltage can accurately and reproducibly be

measured are characterized by a radi- ation conductance determined from

measurements of input voltage and

output power. A typical calibration

report for an ultrasonic system provides the results of at least three

measurements of output power for each operating condition specified.

Calibration reports for transducers

typically present a single value of ra- diation conductance derived from at least 15 measurements spanning an

appropriate range of power. Reso- nance frequencies of transducers are determined from the results of iterative spot-frequency relative measure- ments of radiation conductance.

Continuous-wave ultrasonic power

is measured using a radiation force

balance which allows power to be

determined from the force required

to arrest the motion of a conical

target that diverts the output beam

of the transducer under test into a bank of absorbers. Absolute power

can be measured at spot frequencies

between 1 and 20 MHz. The overall uncertainty varies from 2.2 percent at

1 MHz to 7.6 percent at 20 MHz.

These estimates of uncertainty apply

to measurements made at power

levels ranging from a few milliwatts to a few watts. The minimum detectable

power is about 10 microwatts; highpower measurements are limited by

the onset of cavitation in the water

load. Transducers of diameter no

greater than 45 mm can be tested in

this apparatus.

Pulsed ultrasonic power is measured for the purpose of characterizing ultrasonic systems comprising a transducer and an electrical driver can be tested. Transducers by themselves cannot be independently characterized with nonsinusoidal drive

wave-forms since the electrical input

signals cannot at present be adequately measured or characterized.

The radiation force balance just described is used to characterize pulsed

ultrasonic systems capable of exter- nally-triggered operation at pulse repetition frequencies near 30 Hz.

Systems incapable of external triggering or of operation at 30 Hz p.r.f. are characterized using a specially designed calorimeter. Power levels ranging from 1 mW to several watts at frequencies between 1 and 15 MHz

can be measured with an overall uncertainty less than 10 percent + 0.2 mW. Transducers with diameters as great as 26 mm can be accommodated. Measurements of continuous- wave power are also possible with the

calorimeter; its response time pre- cludes swept-frequency tests.

50
26100C-;-26120S

Special Tests of Ultrasonic Transducer Power (26120S)

This service includes consultation,

customized testing, and the lending of

air-backed transducers for the pur- pose of transferring power measurements. Quartz transducers characterized by radiation conductance and

thus suited for the reproduction of

arbitrary power levels are available

for frequencies of 2, 3, and 5 MHz

and can be specially calibrated for operation at odd overtones. Lithium

niobate transducers with built-in cir- cuitry allowing the field user to repro- duce prearranged power levels while

measuring only dc voltage are avail- able for use at frequencies below 20

MHz approximated by odd multiples

of 0.5 MHz.

References — Ultrasonic Transducer

Measurements

An Ultrasonic Absolute Power Transfer Standard, S. E. Pick,

F. R. Breckenridge, C. E. Tschiegg,

and D. G. Eitzen, J. Res. Natl. Bur. Stand. (U.S.), 89, No. 2, 209

(Mar. 1984).

Ultrasonic Transducer Characterization at the NBS, E. R. Miller and

D. G. Eitzen, IEEE Trans. Sonics

and Ultrasonics, SU-26, No. 1, 28

(Jan. 1979).

Ultrasonic Transducer Power Output

by Modulated Radiation Pressure

(with details), M. Greenspan, F. R. Breckenridge, and C. E. Tschiegg,

Natl. Bur. Stand. (U.S.), NBSIR

78-1520 (July 1978).

Ultrasonic Transducer Power Output

by Modulated Radiation Pressure,

M. Greenspan, F. R. Breckenridge,

and C. E. Tschiegg, J. Acoust. Soc. Am., 63, No. 4, 1031 (Apr. 1978).

Ultrasonic Calorimeter for Beam

Power Measurements from 1 to 15 Megahertz, T. L. Zapf, M. E. Harvey, N. T. Larsen, and R. E. Stoltenberg, 1976 Ultrasonics Symposium Proceedings, IEEE Cat. 76,

CH1120-ISU, Inst, for Electron,

and Electric. Engrs., New York,

NY (1976).

Ultrasonic Calorimeter for Beam

Power Measurements, T. L. Zapf,

M. E. Harvey, N. T. Larsen, and R.

E. Stoltenberg, Natl. Bur. Stand.

(U.S.), Tech. Note 686 (Sept.

1976).

Calibration of Quartz Transducers as Ultrasonic Power Standards by an

Electrical Method, T. L. Zapf, 1974

Ultrasonics Symposium Proceedings, IEEE Cat. 74, CH0896-ISU,

Inst, for Electron, and Electric. Engrs., New York, NY (1974).

51
26200C-26210S

J.

Acoustic Emission Transducer Measurements

Technical Contacts:

Franklin R. Breckenridge

Tel: 301/975-6628

Donald G.

Eitzen

Tel: 301/975-6624

Mailing Address: A147 Sound, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No, Items 26200C

26210S

Acoustic Emission Transducer Amplitude and Phase

Sensitivity versus Frequency

Special Tests of Acoustic Emission Transducers and

Sensors

Acoustic Emission Sensors (26200C)

The NIST acoustic emission trans- ducer calibration provides the voltage

output of a transducer per unit of

motion (displacement or velocity) of

the mounting surface as a function of

frequency. The calibration is based

upon the normal component of motion which would occur in the ab- sence of the transducer. A choice of

two different geometries for the test

is offered as follows: the surfacepulse test in which the transducer un- der test and the source of sound are both on a common plane surface of

the test block, and the through-pulse

test in which the transducer under

test and the source of sound are lo- cated on opposite faces of the test block. The surface-pulse test method is as follows: a step function of "point"

force is generated on the surface of a

large steel block by breaking a glass

capillary. The transducer under test and the NIST standard capacitive

transducer are located on this same

surface and are equidistant from the

source. Both transducers experience

the motion of the seismic surface

pulse generated by the step function

force. The transient voltage outputs

from both transducers are recorded

and analyzed for frequency content. The frequency response of the trans- ducer under test is obtained by divid- ing the spectral amplitude from it by

that from the standard transducer,

frequency by frequency. The calibration is absolute, since the sensitivity

of the standard transducer is known.

The magnitude and phase of the sensitivity of the transducer under test are obtained at discrete frequencies,

f„ = 9765.625n (Hz), where n = 1,2,3... The customer is provided with the results in the form of graphs of magnitude and phase. These are piecewise

linear functions constructed through

the data points. Within the valid

range of 0.1 to 1 MHz, the uncertainty is approximately 10 percent. At

the option of the customer, the results will be given with respect to nor- mal displacement or velocity of the

mounting surface, on a linear scale or on a decibel scale. The through-pulse test method is similar to the surface-pulse test, ex- cept that the transducer under test and the source of sound are located

opposite each other on the top and

bottom plane surfaces of the 43-cmthick test block. For the throughpulse calibration, the reference signal

is obtained not from the standard

transducer but from a calculation

based on the measured force of the

capillary break.

52
26200C-26210S

References— Acoustic Emission

Transducer Measurements

Acoustic Emission Transducer Cali- bration by Means of the Seismic

Surface Pulse, F. R. Breckenridge,

J. Acoust. Emission, 1, No. 2 (Apr.

1985).

Calibration and Sensor Activities,

D. G. Eitzen, F. R. Breckenridge,

R. B. Clough, E. R. Fuller, N. N.

Hsu, and J. A. Simmons, Chapter

2.0 in Fundamental Developments

for Quantitative Acoustic Emission

Measurements, EPRI NP-2089, Research Project 608-1, Palo Alto,

CA, Electric Power Research Insti- tute, 2-1-2-52 (Oct. 1981).

Surface-Wave Displacement:

Absolute Measurements Using a Capacitive Transducer, F. R. Breckenridge and M. Greenspan,

J. Acoust. Soc. Am., 69, No. 4, 1177 (Apr. 1981).

Characterization and Calibration of

Acoustic Emission Sensors, N. N. Hsu and F. R. Breckenridge, Matls.

Eval., 39, No. 1, 60 (Jan. 1981).

Acoustic Emission: Some Applications of Lamb's Problem, F. R.

Breckenridge, C. E. Tschiegg, and

M. Greenspan, J. Acoust. Soc. Am.,

57, No. 3, 626 (Mar. 1975).

53
Chapter

A Pressure Measurements

B Low-Pressure, Vacuum,

and Leak Measurements

C Laboratory Thermometers

D Thermocouples, Thermocouple

Materials, and Pyrometer Indicators E Resistance Thermometry

F Radiation Thermometry

G Humidity Measurements

H Total Heat Flux Gauges
Thermodynamic Quantities 29010C-29040S

Stephen W. Doty R. Gregory Driver Walter Markus Donald B. Ward

29010C, 29030C 29010C, 29030C, 29010C, 29030C 29020C, 29035C

Tel: 301/975-4857 29040S Tel: 301/975-4827 Tel: 301/975-6561

Tel: 301/975-4832

Mailing Address: A55 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 29010C Deadweight Piston Gages

29020C Controlled Clearance Piston Gages

29030C Pressure Gages and Transducers

29035C Mercurial Barometers and Manometers

29040S Special Tests of Pressure Gages

Piston Gages and Pressure Transducers (29010C-29035C)

NIST provides measurement services

for the calibration of piston gages and

transducers operating with gas in the

range of 1.4 kPa to 17 MPa and with

oil in the range of 700 kPa to 400

MPa. Calibrations of customer piston

gages are done in the gage mode by

the cross-floating technique using

NIST working standard piston gages. NIST working standards for use with

gas have been calibrated at the low

end of the pressure range using the

NIST gas thermometer manometer

and at the high end of the range us- ing a controUed-clearance piston gage. The NIST working standards

for oil service have been calibrated

using two controlled-clearance piston

gages. Systematic uncertainties associ- ated with such calibrations are shown

in Table 1.

Table 1: Estimated Systematic Uncertainties of Piston

Gage Calibrations in Gage Mode

Approx. Systematic

Type of Instrument Range Uncertainty

Gas-operated PG 21 kPa to 103 kPa 11 ppm*

83 kPa to 1 MPa 11 ppm*

690 kPa to 5 MPa + 50 ppm*

690 kPa to 17 MPa 50 ppm*

Oil-operated PG 700 kPa to 100 MPa 77 ppm

28 MPa to 280 MPa 73 to ± 150 ppm

40 MPa to 400 MPa 18 6 ppm

* These uncertainties are based on recent evaluations of NIST "transfer" piston gage standards. These estimates are in the process of further evaluation and may be modified (look for announcements in SP250 Supplements).

Calibrations of transducers are performed in both the gage and absolute modes.

Special Tests of Pressure Gages

(29040S)

Special tests of pressure gages and

other pressure measuring devices may

be performed on request. This in- cludes, as a complement to the special test described in Test No. 30040S

for deadweight piston gages, an absolute mode test in the pressure range

21-103 kPa that can provide systematic uncertainties at a level below that which is available in Table 1. A minimum piston gage test will require

data at five or more pressures for each gas desired. Call Mr. Driver or Dr. Ratnam for further information

about this service.

References — Pressure Measurements

The Reduction of Uncertainties for Absolute Piston Gage Pressure Measurements in the Atmospheric

Pressure Range, B. E. Welch, R. E. Edsinger, V. E. Bean and C. D.

Ehrlich, J. Res. Natl. Inst. Stand.

Technol., 94, 343 (Nov.-Dec. 1989).

Observations of Gas Species and

Mode of Operation Effects on Effective Areas of Gas-Operated Pis- ton Gages, B. E. Welch, R. E. Edsinger, V. E. Bean, and C. D.

Ehrlich, High Pressure Metrology,

G. F. Molinar, ed., BIPM Monogr.

89/1, 81 (1989).

55
Practical Uncertainty Limits to the

Mass Determination of a PistonGage Weight, R. S. Davis and

B. E. Welch, J. Res. Natl. Bur. Stand. (U.S.), 93, No. 4 (July-Aug.

1988). Pressure Metrology: Primary Stan- dard Piston Gages, V. E. Bean,

Proc. Xth Conf. of the Intl. Assoc.

for the Advanc. of High Pressure

Sci. and Tech., Amsterdam (July

1985).

Elastic Distortion of Piston Gages,

J. Lazos-Martinez and V. E. Bean,

Proc. Xth Conf. of the Intl. Assoc.

for the Advanc. of High Pressure

Sci. and Tech., Amsterdam (July

1985). Factors Affecting the Precision of

Gas Operated Piston G?ges at the

Part Per Million Level, B. E. Welch, L. A. Guildner, and V. E. Bean, Proc. 31st Intl. Instrum. Symp., San Diego, CA, 9 (May

1985).

Note on the Results of the First Phase of an International Comparison in the Pressure Range 20-100

MPa Organized by the High Pres- sure Working Group of the Comite

Consultatif pour la Masse, J. C. Lagras, V. E. Bean, J. Jager, S. L. Lewis, and G. F. Molinar, J. Phys. E: Sci. Instrum. 18, 361 (1985).

International Comparison in the Pres- sure Range 20-100 MPa Organized

by the High Pressure Working

Group of the Comite Consultatif

pour la Masse, J. C. Legras, V. E. Bean, J. Jager, S. L. Lewis, and

G. F. Molinar, BIPM Internal

Technical Report 84/2, Intl. Bur. of

Weights and Meas., Paris (1984). Pressure and Temperature Measurements in the Annulus between the

Piston and Cylinder of a Simple

Dead-Weight Piston Gauge, B. E. Welch and V. E. Bean, Rev. Sci. Instrum. 55, 1901 (1984).

Effects of Viscosity, Temperature,

and Rate of Rotation on Pressure Generated by a ControlledClearance Piston Gauge, J. K. N. Sharma, K. K. Jain, V. E. Bean,

B. E. Welch, and R. J. Lazos, Rev.

Sci. Instrum. 55, 563 (1984).

A Method to Determine the Pressure Dependent Distortion of a Simple

Piston Gage Based on Dimensional

Metrology, B. E. Welch and V. E. Bean, High Pres. Sci. and Tech.,

22, II, 261, C. Homan, R. K. MacCrone, and E. Whalley, Eds.,

Elsevier Science Publishing Co.,

Inc., New York (1984).

An Intercomparison of Pressure Stan- dards between IMGC and NBS,

J. C. Houck, G. F. Molinar, and

R. Maghenzani, J. Res. Natl. Bur.

Stand. (U.S.), 88, 253 (1983).

An Intercomparison of Pressure Stan- dards between LNE and NBS,

R. G. Driver, J. C. Houck, and

B. E. Welch, J. Res. Natl. Bur.

Stand. (U.S.), 86, No. 3 (May-June

1981).

Absolute High Pressure Measurements, V. E. Bean, High Pressure Science and Technology, B. Vodar

and P. Mardeau, Eds., 231, Pergamon Press, Oxford, England (1980).

Piston Gages, P. L. M. Heydemann

and B. E. Welch, Chapter 4, Experimental Thermodynamics,

Vol. II, in Experimental Thermodynamics of Non-Reacting Fluids, B. Le Neindre and B. Vodar, Eds., Part 3, 147, Butterworth and Co.,

London, England (1975).

Reduction of Data for Piston Gage

Measurement, J. L. Cross, Natl. Bur. Stand. (U.S.), Monogr. 65

(1963).

56
30010C-30060S

B. Low-Pressure, Vacuum, and Leak

Measurements

Technical Contacts:

Richard W. Hyland

30010C-30021C,

30025C, 30040S, 30050S

Tel: 301/975-4829

Sharrill Dittmann

30029C-30038C, 30050S

Tel: 301/975-4838

Stuart A. Tison 30060S

Tel: 301/975-2857

Mailing Address: A55 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and Technology, 1-270 at Quince Orchard Rd., A52 Metrology,

Gaithersburg, MD 20899-0001

Test No. Items 30010C

30011C

30020C

30021C

30025C

30029C

30030C

30031C

30034C

30035C

30036C

30037C

30038C

30040S

30050S

30060S

Absolute Low-Pressure Transducers

Up to Two Additional Transducers (cost per unit) Differentia! Low-Pressure Transducers Relative

to Vacuum

Up to Two Additional Transducers (cost per unit)

Ball-Type Deadweight Tester Molecular Drag Gages, Without Customer Controller Molecular Drag Gages, With Customer Controller Molecular Drag Gages, Additional Ball or Gas

Ionization Gages, 10"'' to 10"' Pa, Nitrogen Gas

Ionization Gages, 10"^ to 10"' Pa, Nitrogen Gas

Ionization Gages, 10"^ to 10"' Pa, Nitrogen Gas

Ionization Gages, Additional Filament or Gas for Above Tests

Ionization Gages, NIST Supplied Gage Tube for Above Tests

Special Tests of Low-Pressure Gages

Special Tests of Vacuum Gages

Special Tests of Leak Artifacts

Low-Pressure Transducers (30010C30011C, 30020C-30021C and 30025C)

Absolute low-pressure gages including

capacitance diaphragm gages and

quartz spiral gages are calibrated

against the NIST Ultrasonic Interfer- ometer Manometer. This standard

covers a range limited at the low end

by its 10 mPa (10"'' Torr) imprecision

and extending up to 360 kPa (2700

Torr, 53 psi). The uncertainty of the

standard is 15 ppm of reading plus 10

mPa. This standard is also used for the calibration of low-range differential gages, including ball gages, and

gas-operated piston gages (see

30040S). Calibrations are generally

performed during February and July. Instruments scheduled for these regular calibration periods must be re- ceived in the calibration laboratory

before the fifth working day of February or July, respectively. Calibrations can be performed at other times by

special arrangement. A fee will be

charged to cover time lost because of

inoperative customer equipment.

Molecular Drag and Ionization Gages

(30029C-30038C)

A standard of the orifice flow type

covers the range from 10"' to 10"^ Pa

(10"^ to 10""* Torr) for most gases with an uncertainty of 1 percent between 10"^ and 10"" Pa increasing to 5 percent at 10"^ Pa. Ionization gages

and molecular drag or spinning rotor gages are accepted for calibration but

all gages must be bakeable to 250 °C

and should be welded to "Conflat"

type flanges. Standard procedure is to calibrate the sensor and electronics as a package, although sensors may be

calibrated using NIST electronics by

special arrangement. Note that ionization gage controllers that do not

regulate the emission current or controllers that deliberately change the current are not considered suitable as transfer standards. Calibration fees

will depend on the pressure range. For any of the tests 30034C-30036C,

additional filaments will be calibrated

at the same time, or calibrations per- formed with additional gases, for a reduced charge (30037C). A fee will be charged to cover time lost because

of inoperative customer equipment.

Similarly, for tests 30029C and

30030C additional rotors will be cali- brated, or calibrations will be per- formed with additional gases for a reduced charge (30031C).

57
30010C-30060S

For an additional fee NIST will provide tubulated Bayard-Alpert ion- ization gages with tungsten filaments

and 2.75 in. "Conflat" type flanges

(30038C). These will be calibrated

with the user's electronics.

Special Tests of Low-Pressure Gages

(30040S) Instruments requiring special calibra- tion procedures or prolonged testing can often be accommodated as a special test. This includes, as a complement to the 29000 series of tests, the

determination of deadweight piston

gage effective area using the NIST ul- trasonic interferometer manometer as the reference standard. This test can be done in either the gage or absolute mode for a variety of gases. A

minimum piston gage test will require

data for at least one gas in the absolute mode at five or more pressures. For further information contact R. W. Hyland.

Special Tests of Vacuum Gages

(30050S) Instruments requiring special calibra- tion procedures or prolonged testing can often be accommodated as a

special test. Consult with S. Dittmann

for further details.

Special Tests of Leak Artifacts

(30060S)

A special-test service is offered for helium leak artifacts in the range

10"' to 5 X lO"'" mol/s (2 x lO"' to 1 x IQ-' atm cc/s at 0 °C). The Report of Test provides tabulated leak rates at

1 °C intewals from 0 °C to 50 °C,

based on absolute measurements

taken on the Primary Leak Standard

(referenced to 23 °C), and temperature-dependence measurements taken on a controlled-temperature leak rate comparator system. Typical uncertainties for the calibrated leaks (3ct) are between 3 and 10 percent. All leak

artifacts submitted for measurement

must be of ultrahigh vacuum compatible, clean and with all-metal construction except for the glass

permeation element. The vacuum

connection must be a standard 2.75"

"conflat" type flange. An easily observable customer identification number or code must be engraved on the

circumference of the 2.75" flange.

Special test of leaks for gases other

than helium will be considered on a case-by-case basis. For further infor- mation contact S. A. Tison.

Figure 5 summarizes the uncertainties of the NIST low-pressure and vacuum standards. Dashed lines are

target uncertainties expected from new standards under development or improvements to existing standards.

Figure 5. Uncertainties of NIST Low Pressure and

Vacuum Standards

-10 -8 LOG PRESSURE (Torr)

-6 -4 -2 0

QC

Hi -3 O

Z)O

-4

-6

ULTRA HIGH VACUUM ^ 1

I

\ ' r

TRANSITION

- RANGE STANDARD -\ (UNDER DEVELOPMENT)

ATMOSPHERIC PRESSURE

ORIFICE FLOW^ STANDARD

ULTRASONIC MANOMETER

-8 -4-2 0 2 LOG PRESSURE (Pa)

References — Low-Pressure, Vacuum,

and Leak Measurements

A Study of the Linearity of Transfer

Leak Standards and a Helium Leak

Detector, C. D. Ehrlich, S. A. Tison, H. Y. Hsiao, and D. B. Ward,

J. Vac. Sci. Technol. (Nov. 1990).

The Molecular Drag Gauge as a Calibration Standard, S. Dittmann,

B. E. Lindenau, and C. R. Tilford,

J. Vac. Sci. Technol., A7, 3356

(1989).

NIST Measurement Services: High

Vacuum Standard and Its Use,

S. Dittmann, Natl. Inst. Stand.

Technol. Spec. Publ. 250-34 (1989).

58
Sharrill Dittmann with the primary high vacuum standard used for the calibration

of spinning rotor and ionization gages.

The NBS Ultrasonic Interferometer

Manometer and Studies of GasOperated Piston Gages, C. R. Til- ford and R. W. Hyland, Metrology,

Proc. 11th Triennial World Congress of the Int. Meas. Conf.

(IMEKO), 277, Instrum. Soc. of

America, Res. Triangle Park, NC,

Houston, TX (Oct. 16-21 1988).

New Developments in Barometric

Range Pressure Standards, C.R.

Tilford, Proc. 1988 Natl Conf.

Stand. Lab. Ann. Workshop and

Symp., 35-1 to 35-15 (1988).

The NBS Primary High Vacuum

Standard, C. R. Tilford, S. Dittmann, and K. E. McCulloh, J. Vac. Sci. Technol. A6, 2853 (1988).

The Speed of Sound in a Mercury Ultrasonic Interferometer Manometer, C. R. Tilford, Metrologia 24, 121 (1987).

30010C-30060S

Lx)w-Range Flowmeters for Use with

Vacuum and Leak Standards, K. E. McCulloh, C. R. Tilford, C. D.

Ehrlich, and F. G. Long, J. Vac.

Sci. Technol., A5, 376 (1987).

Transfer Leak Studies and Comparisons of Primary Leak Standards at the National Bureau of Standards

and Sandia National Laboratories, R. W. Hyland, C. D. Ehrlich, and

C. R. Tilford, J. Vac. Sci. Technol.,

A4, 334 (1986).

A Note on Flow Rate and Leak Rate

Units, C. D. Ehrlich, J. Vac. Sci. Technol., A4, 2384 (1986).

Zero Stability and Calibration Results

for a Group of Capacitance

Diaphragm Gages, R. W. Hyland

and C. R. Tilford, J. Vac. Sci. Technol., A3, 1731 (1985).

Zero Stability of Spinning Rotor Vacuum Gages, K. E. McCulloh,

S. D. Wood, and C. R. Tilford,

J. Vac. Sci. Technol., A4, 1738

(1985).

Long-Term Stability of Two Types of

Hot Cathode Ionization Gages,

S. D. Wood and C. R. Tilford,

J. Vac. Sci. Technol., A3, 542

(1985).

Sensitivity of Hot Cathode Ionization

Gages, C. R. Tilford, J. Vac. Sci. Technol., A3, 546 (1985).

Reliability of High Vacuum Measurements, C. R. Tilford, J. Vac. Sci. Technol., Al(2), 152 (Apr.-June

1983).

Ultrasonic Manometers for Low and

Medium Vacua Under Development at NBS, P. L. M. Heydemann,

C. R. Tilford, and R. W. Hyland, J. Vac. Sci. Technol., 14, 597 (Jan.-

Feb. 1977).

59
31010C-31260S

Laboratory Thermometers

Technical Contact:

Jacquelyn A. Wise

Tel: 301/975^22

Mailing Address: B126 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and Technology, 1-270 at Quince Orchard Rd., A242 Physics,

Gaithersburg, MD 20899-0001

Attn: J. Wise

Test No. Items 31010C Laboratory Thermometers (0 to 150 °C)

(32 to 302 °F)

31020C Laboratory Thermometers (151 to 300 °C)

(304 to 572 °F)

31030C Laboratory Thermometers (301 to 550 °C)

(574 to 1022 °F)

31040C Laboratory Thermometers ( - 1 to - 1 10 °C)

(30 to - 166 °F)

31050C Laboratory Thermometers (Liquid N2)

(-196°Cor -321 °F)

31060C Laboratory Thermometers (Liquid O2)

(-183°Cor -297°F)

31070C Calorimctric Thermometer

31080C Beckmann Thermometer

31100C Quantity Tests of Liquid-in-Glass Thermometers

31110S Special Tests of Thermometers (0 to 150 °C)

(32 to 302 °F)

3 11 20s Special Tests of Thermometers (151 to 300 °C)

(304 to 572 °F)

31130S Special Tests of Thermometers (301 to 550 °C)

(574 to 1022 "F)

3 1 140S Special Tests of Thermometers ( - 1 to 1 1 0 °C)

(30 to - 166 °F)

31150S Special Tests of Thermometers (Liquid N^)

(-196°Cor -321 °F)

31160S Special Tests of Thermometers (Liquid O2)

(-183°Cor -297T)

31200S Preliminary Exam or Ineligible Thermometer

31250S Additional copy of report

31260S Special Thermometry Services, by Prearrangement

Laboratory Thermometers

(31010C-31100C)

This service provides for the calibra- tion of a variety of thermometers

covering the range from — 196 to -f-550°C (-320 to -H022°F).

Thermometers belonging to the

large and varied group, which may be

classed as laboratory or "chemical"

thermometers, are regularly

accepted. These are of the liquidin-glass type with either solid-stem or enclosed scale. Ordinary household

or meteorological thermometers will not, in general, be accepted unless

the scale is graduated on the glass

stem itself and the thermometer can be readily detached from its mounting

for insertion in a liquid bath. Every

thermometer submitted must be

uniquely identified by a serial number

and must pass a preliminary examination for fineness and uniformity of

graduation; for cleanliness of the

mercury and capillary bore; for free- dom from moisture, gas bubbles, and

cracks in the glass; for adequacy or omission of gas filling where needed;

for insufficient annealing; and for misnumbered graduations. When

these or other serious defects are found, the thermometer is returned

untested.

The thermometers to be calibrated are placed in a constant temperature

bath along with a NIST-calibrated

standard platinum resistance ther- mometer (SPRT). The SPRT maintains calibrations traceable to the

International Practical Temperature

Scale of 1990 (ITS-90), with an uncertainty of = 1 mK. (See Table 2.)

60
310100-312605

Table 2: Thermometer Calibration Uncertainties

Type of Thermometer

(Total Immersion)

Range Uncertainty

Mercury-in-glass 0 to 100 °C

(graduations: 0.1-0.2 °C)

Mercury-in-glass 0 to 300 °C

(graduations: 1-2 °C) 300 to 550 °C

Organic liquid-in-glass - 200 to 0 °C

0.03 to 0.05 °C

0.2 to 0.5 °C

0.5 to 1.0 °C

0.2 to 0.5 °C

Special Tests of Thermometers

(31110S-31160S)

Special tests may be conducted on

temperature-measuring devices such

as industrial grade platinum resis- tance thermometers, digital ther- mometers, and thermistors.

Laboratory personnel should be contacted before submitting items.

Figure 6 summarizes the relative NIST uncertainties for different types

of temperature-measuring instru- ments, including thermometers, ther- mocouples, and pyrometers. See also following sections.

References — Laboratory Thermometers

The International Temperature Scale

of 1990 (ITS-90), H. Preston- Thomas, Metrologia 27, 3-10

(1990); Metrologia 27, 107 (1990).

ASTM Standard El-89, Specification

for ASTM Thermometers, Annual

Book of ASTM Standards 14.03, 1, Amer. Soc. for Test, and Matls.,

Philadelphia, PA (1990).

ASTM Standard E77-89, Methods of

Verification and Calibration of Liquid-in-Glass Thermometers, Annual

Book of ASTM Standards 14.03,

60, Amer. Soc. for Test, and Matls.,

Philadelphia, PA (1990).

NIST Measurement Services: Liquidin-Glass Thermometer Calibration

Service, J. A. Wise, Natl. Inst. Stand. Technol. Spec. Publ. 250-23

(Sept. 1988).

Thermometer Calibration: A Model

for State Calibration Laboratories,

J. A. Wise, R. J. Soulen, Natl. Bur.

Stand. (U.S.), Monogr. 174 (Jan.

1986).

Figure 6. Uncertainties for NIST Calibration of

Temperature Measuring Instruments

(Relative to ITS-90)

101

100 TO

]

/

RIRTs \ SPRTs /

0.1 1 10 100 1000 10000

Temperature (K)

61
32010C-32150S

D Thermocouples, Thermocouple Materials,

and Pyrometer Indicators

Technical Contacts:

George W. Burns

32010C-32101C, 32150S

Tel: 301/975-4817

Margaret G.

Scroger 32010C-32101C, 32150S

Tel: 301/975-4818

Jacquelyn A. Wise

32110C-32147C

Tel: 301/975-4822

Mailing Address: B126 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

For 32010C-32101C, 32150S

[Attn: G. Burns or M. Scroger, Bldg. 221, Room B229]

For 32110C-32147C

[Attn: J. Wise, Bldg. 221, Room A242]

Comparison Calibrations, Temperature Measured with Thermocouple:

Test No. Items Temp. Min. Est. TC Range Points Length Temp. Uncert Type °C mm °C °C

32010C S 0-1450

32020C R 0-1450

32030C B 0-1750

32031C B 800-1750

1

° or 1 °F

Interv. Table

700

700

1000

0-600 0.5 600-1100 0.5 1450 0-600

2

0.5 600-1100 0.7 1450 2 0-600 (3p.V)

600-1100 0.5 1450

1750

2

3 1000 800-1100 0.7 1450 2 1750 3

Comparison Calibrations, Temperature Measured with Thermocouple:

Test No. Items

32040C

3204 IC

32042C

32043C

32044C

32050C Comparison calibration, 2 point minimum, per point, for all items above

32060C Each additional table of results at 1 °C or 1 °F

intervals, for Type S, R, or B at later date 32061 C Each additional table of results at 1 °C or 1 °F

intervals, for Type S, R, or B at time of test 32070C Thermocouple materials tested against Pt thermoelectric standard, 4 to 15 points, 700 mm minimum

lengths

Calibration at Metal Freezing Points, Minimum

Diameter 0.4 mm, Freezing Point Determination at Au, Ag, Sb, and Zn

Temp. Min. Est. TC Range Points Length Temp. Uncert Type °C mm °C °C

E 0-1000 4 to 15 700 1 J 0-760 4 to 15 700 1 K 0-1100 4 to 15 700 1 N 0-1100 4 to 15 700 1 T 0-400 4 to 15 700 1

32090C S 0-1450 Table, 1 °C or

1 °F interv. and

equations to generate table

1000 at freezing

points

0 to 700

700 to 1100

1450

0.2

0.3 0.4 2 32091C Type S, freezing point determination, per point, 2

point minimum

Calibration of Pyrometer Indicators 32100C Portable Potentiometer, first dial or range 32101C Portable Potentiometer, each additional dial or range

62
32010C-32150S

Comparison Calibrations, Temperature Measured with Platinum Resistance Thermometer:

Test No. Items

Comparison Calibration of Thermocouples or Thermocouple Materials Tested against Pt

Thermoelectric Standard, Temperature Measured

with Platinum Resistance Thermometer, Minimum

Length 36 Inches, 2 Point Minimum

' 32110C Range - 110 to +300 °C and Liquid Nz (- 196 °C) or - 166 to 572 °F and Liquid Nz ( - 321 °F)

32120C 301 to 550 "C or 574 to 1022 °F 32130C Liquid O2 ( - 183 °C) or ( - 297 °F)

Table at one degree intervals for Type T thermoI couple for any of the following options:

(The cost of the table will be in addition to the

calibration per point covered under fee schedule items numbered 32110C-32130C.)

I 32141C Option 1: Table from -190 to +300°C

] ( - 310 to + 572 °F), calibration points at - 183,

' -110, -50, +100, +200, +300°C

j 32142C Option 2: Table from - 190 to + 100 "C

! ( - 310 to + 212 °F), calibration points at - 183, -110, -50, +50, +100°C

' 32143C Option 3: Table from - 110 to +300 °C

( - 166 to + 572 °F), calibration points at - 1 10, - 50, + 100, +200, +300°C

' 32144C Option 4: Table from - 110 to + 100 °C

' (-166 to +212 °F), calibration points at -110, -50, + 50, +100°C

\ 32145C Option 5: Table 0 to 300 °C (32 to 572 °F),

i calibration points at +100, +200, +300°C

' 32146C Option 6: Table from - 110 to 0 °C ( - 166 to + 32 °F), calibration points at - 110, -50 °C.

; 32147C Option 7: Table from - 190 to 0 °C ( -310 to + 32°F), calibration points at -183, -110, -50°C

ill 32150S Special Tests of Thermocouples and Thermocouple

Materials

Thermocouples, Thermocouple

Materials, and Pyrometer

Indicators (32010C-32147C)

Calibration services for all commonly

used types of thermocouples are pro- vided by NIST from - 196 to 1750 °C

depending upon the wire or thermocouple type. The thermocouples are

calibrated by one or a combination of

three general methods, depending on the thermocouple type, the temperature range, and the accuracy re- quired. All three methods provide

traceability to the ITS-90. In the first method, thermocouples are calibrated

by comparison with a standard ther- mocouple maintained at NIST. In the

second method, thermocouples are

calibrated by comparison with a stan- dard platinum resistance thermometer. In the third method, thermocouples are calibrated at three defining temperatures on the ITS-90 — the

freezing points of Zn, Ag, and Au, as well as at the freezing point of

Sb( = 630.62 °C). Below 0°C the

thermocouple calibration is carried out in a cryostat, while above 0 °C

stirred liquid baths, metal freezingpoint cells, and electric tube-type

furnaces are employed for the cali- brations. Vacuum or inert gas fur- naces are also available for testing

thermocouples.

Only the bare wires are required to perform the thermocouple calibrations. It is preferable not to send in- sulating and protecting tubes as the

rate of breakage of these in shipment

is high. If the thermocouple is fur- nished mounted (as in a protection

tube assembly), a nominal charge will be made for dismantling the mounting and the various parts will be re- turned to the sender without

reassembling them. Thermocouple

length requirements listed in the ap- pendix are exclusive of lead wire.

Lead wires (for connections) need

not be sent with thermocouples. All thermocouple calibration data fur- nished in reports will be on the basis

of a reference junction temperature

of 0 °C (32 °F). The calibration results

will be given in degrees C or F, as re- quested by the customer.

63
The calibration of a thermocouple

will not be undertaken if it will likely not yield the specified accuracy or if

it possesses unusual characteristics that would prevent the carrying out of

the calibration or test at a reasonable

cost. Only unused base-metal thermocouples and thermocouple materials

will be accepted for test.

Special Tests of Thermocouples and

Thermocouple Materials (32150S)

For requirements not covered by cali- brations described above, special

arrangements may be made by contacting one of the specified staff members.

References — Thermocouples

The International Temperature Scale

of 1990 (ITS-90), H. Preston- Thomas, Metrologia 27, 3-10

(1990).

NIST Measurement Services: The

Calibration of Thermocouple and

Thermocouple Materials, G. W.

Burns and M.G. Scroger, Natl. Inst. Stand. Technol. Spec. Publ. 250-35

(Apr. 1989).

ASTM Standard E220-86, Standard

Method for Calibration of Thermocouples by Comparison Techniques,

Annual Book of ASTM Standards,

14.01, 225, Amer. Soc. for Test,

and Matls., Philadelphia, PA

(1987).

ASTM Standard E230-87, Temperature-Electromotive Force (EMF)

Tables for Thermocouples, Annual

Book of ASTM Standards, 14.01,

242, Amer. Soc. for Test, and

Matls., Philadelphia, PA (1987).

American National Standard,

Temperature Measurement Thermocouples, ANSI-MC96.1-1982, Instr. Soc. of Amer., Res. Triangle

Park, NC (1982).

Manual on the Use of Thermocouples

in Temperature Measurement,

ASTM STP 470B, Amer. Soc. for Test, and Matls., Philadelphia, PA

(1981).

Accurate Thermocouple Thermometry, L. A. Guildner and G. W.

Burns, High Temperatures— High

Pressures, 11, 173 (1979).

International Electrotechnical Commission Standard, Thermocouples,

Part I: Reference Tables, lEC Publication 584-1, Intl. Electrotech.

Com., Geneva (1977).

Thermocouple Reference Tables

Based on the IPTS-68, R. L. Powell, W. J. Hall, C. H. Hyink,

Jr., L. L. Sparks, G. W. Burns,

M. G. Scroger, and H. H. Plumb,

Natl. Bur. Stand. (U.S.), Monogr.

125 (1974).

64
33010C-33390M

Earl R. Pfeiffer Gregory F. Strouse

0.65 K to 84 K 83 K to 962 °C

Tel: 301/975-4821 Tel: 301/975-4803

Mailing Address: B126 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, B04

Physics, Gaithersburg, MD 20899-0001

Attn: E. R. Pfeiffer or G. F. Strouse

Test No. Items 33010C Capsule PRT (13.8 K to 30 °C)

33020C Capsule PRT (13.8 K to 157 °C)

33030C Capsule PRT (13.8 K to 232 °C)

33040C Capsule PRT (54 K to 30 °C)

33050C Capsule PRT (54 K to 157 °C)

33060C Capsule PRT (54 K to 232 °C)

33070C Capsule PRT (84 K to 30 °C) Ar to Ga

33080C Capsule PRT (84 K to 157 °C) Ar to In 33090C Capsule PRT (84 K to 232 °C) Ar to Sn

33100C Capsule PRT (0 °C to 30 °C) TPW to Ga

33110C Capsule PRT (0 °C to 157 °C) TPW to In 33120C Capsule PRT (0 °C to 232 °C) TPW to Sn

33130C Capsule PRT (234 K to 30 °C) Hg to Ga

33140C Germanium and Rhodium-Iron Resistance

Thermometers (0.65 K to 24.6 K)

I 33150C Long Stem PRT (83 K to 0 °C) Ar to TPW

(' 33160C Long Stem PRT (83 K to 30 °C) Ar to Ga

33170C Long Stem PRT (83 K to 157 °C) Ar to In 33180C Long Stem PRT (83 K to 232 °C) Ar to Sn

33190C Long Stem PRT (83 K to 420 °C) Ar to Zn

j 33200C Long Stem PRT (83 K to 661 °C) Ar to Al

I 33210C Long Stem PRT (234 K to 30 °C) Hg to Ga

j 33220C Long Stem PRT (234 K to 157 °C) Hg to In

II 33230C Long Stem PRT (234 K to 232 °C) Hg to Sn

33240C Long Stem PRT (234 K to 420 °C) Hg to Zn

' 33250C Long Stem PRT (234 K to 661 °C) Hg to Al

33260C Long Stem PRT (0 °C to 30 °C) TPW to Ga

Test No. Items

33280C Long Stem PRT (0 °C to 232 °C) TPW to Sn 33290C Long Stem PRT (0 °C to 420 °C) TPW to Zn

33270C Long Stem PRT (0 °C to 157 °C) TPW to In 33300C Long Stem PRT (0 °C to 661 °C) TPW to Al 33310C Long Stem PRT (0 °C to 962 °C) TPW to Ag

33320C Additional Copy of Table from Results of 33010C-33310C at Time of Test 33330C Additional Copy of Table from Results of 33010C-33310C at a Later Date 33340C Minimum Charge for Unsuitable Thermometer

33350S Special Tests of Resistance Thermometers

33360S Special Tests of Thermometric Fixed-Point Devices

33370M Measurement Assurance Program for Temperature

(83 K to 420 °C) Ar to Zn

33380M Measurement Assurance Program for Temperature

(83 K to 661 °C) Ar to Al

33390M Measurement Assurance Program for Temperature

(0 °C to 962 °C) TPW to Ag

Resistance Thermometers

(33010C-33310C)

NIST provides calibration services for standard platinum resistance ther- mometers (SPRTs) from 13.8 K to 1235 K. Both long-stem and capsuletype SPRTs are calibrated, providing

direct access to the International

Temperature Scale of 1990 (ITS-90).

The reproducibility of the calibration

measurements of SPRTs is better

than ±0.3 mK and the total uncertainty of calibration is ± 1 mK at temperatures below 661 °C. The re- producibility increases to about ±0.5

mK and the uncertainty to about ±2

mK at 962 °C. The reproducibility of

triple point of water (TPW) cells used

for calibration of SPRTs is ±50 ^LK or better while that for Ar, Hg, Ga,

In, Sn, Zn, and Al triple-point or

freezing-point cells is ±0.1 mK; and

that for Ag freezing-point cells is ±0.5 mK. Presently, the NIST temperature scale in the range 13.8 K to 84 K is based on stable reference

SPRTs of the capsule type that have

uncertainties of about ± 0.3 mK down

to about 20 K. Below 20 K, the uncertainty degrades to about ± 0.5 mK

as the SPRTs become less sensitive.

65
33010C-33390M

For calibration of rhodium-iron resis- tance thermometers (RIRTs) and

germanium resistance thermometers

(GRTs) in the temperature range

from 0.65 K to 24.6 K, the NIST

scale is based presently on a set of

reference capsule-type RIRTs. The

uncertainty of those calibrations is about ± 0.3 mK.

To qualify for testing, either longstem or capsule SPRTs must meet

two conditions. They must reasonably

be expected to meet the requirements

of the ITS-90 for a standard interpolating instrument (i.e., a four lead resistor of high-purity platinum

hermetically sealed in a protecting

tube). Second, they must be compatible with the NIST calibration equipment. It is important that, insofar as possible, resistance thermometers be

protected from any mechanical shock

that could alter their calibration. For

shipment, the thermometer should be

softly supported within a case but not be free to rattle. This necessitates the use of packing material that does not become compacted. The thermometer

case should be softly packed inside a shipping container. The shipping container must be sufficiently rigid and

strong that it will not appreciably deform under the treatment usually

given by common carriers. Styrofoam

is not sufficiently rigid to be used as an outside container. Thermometers

will not be returned in containers that are obviously unsuitable, such as those closed by nailing. Suitable containers will be provided, for a fee,

when a thermometer shipping container is not satisfactory for re-use.

Special Tests of Resistance

Thermometers and Special Tests

of Thermometric Fixed-Point Devices

(33350S and 33360S)

Special tests of various resistance

thermometers and thermometric fixed

point devices may be made by pre- arrangement with the specified technical contacts.

Measurement Assurance Program for Temperature (33370M, 33380M, and

33390M)

The purpose of this MAP service is to assure the accuracy of the calibration

of temperature standards (83 K to either 420 °C or 661 °C, or 0 "C to 962 °C temperature ranges) made by

participating laboratories when using

platinum resistance thermometry.

The MAP transport standard consists of a set of three commercial

glass-sheathed SPRTs packaged in a

special shock-proof shipping container (mechanical shock may result

in shifts in calibration). These

SPRTs are used to assess both the

reproducibility and the accuracy of

calibrations performed by the participating laboratory.

MAP participants should use the

techniques described in NIST Technical Note 1265 and the same fixed

points as those used in the NIST cali- brations, or use an SPRT previously

calibrated by NIST. In order to achieve high accuracy, SPRTs used as standards should be of the matte-finish type to avoid systematic errors

arising from light-pipe effects in the

glass sheath. The participant must

have a triple point of water cell and a

calibrated resistance bridge.

After unpacking and inspecting the

SPRTs for damage, the participant

should measure the resistances of the

SPRTs at the triple point of water

(using the triple-point cell). This pre- liminary measurement of the resis- tances at the triple point of water is used as a "go/no go" check to ensure

that the thermometers have not been

damaged in shipment.

These preliminary measurements

are reported by telephone to NIST; if the values are consistent with the

data taken by NIST before shipment,

the participant should proceed with

further measurements at the fixed

points of the ITS-90. NIST provides

a worksheet on which the participant

should record data. The participant

then calculates the thermometer constants from experimental data.

66
33010C-33390M

records them, and prepares tables of

either resistance ratio or resistance versus temperature.

The SPRTs are recaUbrated upon

return to NIST and the participant's

data are compared with NIST's caUbrations. NIST provides a plot of the

participating laboratory's temperature

deviation from NIST values and a written analysis of the data, including

any pertinent observations. In a typi- cal MAP transfer, the participant

makes several measurements over a period of one to two months. A typi- cal turnaround time from the date

NIST receives the participant's data

until a test report is sent to the participant is four to six weeks.

The best NIST SPRT calibrations

have precisions of about 0.1 to 0.2 mK. Sources of error that may contribute to the total uncertainty in- clude changes in the calibration of

the measurement instruments,

changes in the SPRT itself, and uncertainty of the degree of purity of

the materials used as fixed-point ref- erences (e.g., zinc). As a result of

quantifying these errors, NIST cur- rently assigns an uncertainty of ± 1 mK to the values assigned to the

MAP transport standards used below

661 °C. A standards laboratory conscientiously participating in this MAP

and having suitable equipment should

be able to closely approximate this uncertainty figure. Former participants in the MAP have had uncertainties that ranged from about 1 mK

to several tens of millikelvin. No rigid recommendations can be

given concerning how often a participant should utilize the temperature

MAP service. Experience has indi- cated that when temperature measurements are in a state of statistical control, as evidenced by in-house

check standards and control charts

used to monitor the measurement

process, the participant should be

able to go at least three years between transfers from NIST without

significantly degrading the confidence

in the correctness of the measurements.

Gregory Strouse is preparing to insert an SPRT into tiie argon triple-point apparatus. Ttie argon Triple-point

temperature is used in the calibration of SPRTs on the

ITS-90.

References — Resistance Thermometry

The International Temperature Scale

of 1990 (ITS-90), H. Preston- Thomas, Metrologia 27, 3-10

(1990); Metrologia 27,107 (1990).

Special Report on the International

Temperature Scale of 1990, Report on the 17th Session of the Consultative Committee on Thermometry,

B. W. Mangum, J. Res. Natl. Inst. Stand. Technol. 95, 69 (1990).

Guidelines for Realizing the International Temperature Scale of 1990

(ITS-90), B.W. Mangum and G. T. Furukawa, Natl. Inst. Stand. Technol., Tech. Note 1265 (Aug. 1990).

67
NBS Measurement Services: Plat- inum Resistance Thermometer Calibrations, B. W. Mangum, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-

22 (1988).

The Determination of the Triplepoint and Freezing-point Temperatures of Indium, B. W. Mangum,

Metrologia 26, 211-217 (1989).

Reproducibility of Some Triple Point

of Water Cells, G. T. Furukawa

and W. R. Bigge, Temperature, Its Measurement and Control in Sci- ence and Industry, Vol. 5, 291,

Amer. Inst. Phys., New York, NY

(1982).

Standard Reference Materials: Application of Some Metal SRM's as Thermometric Fixed Points, G. T. Furukawa, J. L. Riddle, W R.

Bigge, and E. R. Pfeiffer, Natl. Bur. Stand. (U.S.), Spec. Publ. 260-

77 (Aug. 1982).

A Measurement Assurance Pro- gram—Thermometer Calibration,

G. T. Furukawa and W. R. Bigge,

in Testing Laboratory Performance,

Evaluation, and Accreditation,

Natl. Bur. Stand. (U.S.), Spec.

Publ. 591, 137 (Aug. 1980).

Determination of the Triple-point

Temperatures of Gallium, B. W.

Mangum and D. D. Thornton,

Metrologia 15, 201-215 (1979).

Platinum Resistance Thermometry,

J. L. Riddle, G. T. Furukawa, and

H. H. Plumb, Natl. Bur. Stand.

(U.S.), Monogr. 126 (Apr. 1973).

68
350 lOCJP

Radiation Thermometry

Technical Contacts:

Charles Robert D. Edward

Gibson Saunders Hunter

Tel: 301/975-2329 Tel: 301/975-2328 Tel: 301/975-2130

Mailing Address: A221 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 35010C Optical Pyrometers (1 range between 800 to 2400 °C, 4 to 12 points)

35020C Optical Pyrometers (per range in addition up to 4200 °C)

35030C Additional Interpolated Values

35040C Optical Pyrometers (3 or fewer points, 800 to 4200 °C)

35050C Ribbon Filament Lamp (6 to 16 points, 800 to 2300 °C)

35G60C Ribbon Filament Lamp (5 or fewer points, 800 to 2300 °C)

35070S Special Tests of Radiation Pyrometers

Optical Pyrometers and Ribbon

Filament Lamps (35010C-35060C)

These calibration services provide ac- cess to the ITS-90 as realized by

NIST for the temperature range

800 °C to 4200 °C. High-precision

monochromatic visual and automatic

optical pyrometers are calibrated in that temperature range. Uncertainties

in routine testing vary from ± 3 °C at 1064 °C, and ± 8 °C at 2800 °C, to ±30 °C at 4200 °C. Ribbon filament

lamps are calibrated using the NIST

photoelectric pyrometer, and reports

of brightness temperature at 655 nm

versus direct current are issued. Uncertainties in routine testing vary from ±0.75 °C at 1064 °C to ±2 °C at 2300 °C.

The radiation thermometry portion

of ITS-90 is defined in terms of a

fixed temperature for the freezing

point of gold (1064.18 °C) and the

Planck equation for the radiation of a blackbody source. In practice, temperature scales are realized by constructing a gold point blackbody and

a variable temperature blackbody,

and then measuring spectral radiance

ratio at a red wavelength (approximately 650 nm) in terms of the

Planck equation. Gold point blackbodies are reproducible to ± 0.02 °C,

but the temperature assignment of

the freezing point of gold is uncertain

by about ±0.4 °C. The spectral radi- ance ratio measurements can be per- formed with an uncertainty of 0.2 to 0.3 percent. Higher accuracies than

available in the routine tests described above can be provided as special tests subject to the ITS-90

uncertainties noted. Calibrations at wavelengths other than 650 nm can be provided in the wavelength range

250 to 2500 nm subject to an additional uncertainty due to the quality

of the variable temperature blackbody.

Special Tests of Radiation Pyrometers

(35070S)

Calibrations at wavelengths other

than 650 nm can be provided in the

wavelength range 250 nm to 2500 nm

subject to an additional uncertainty

due to the quality of the variable temperature blackbody. Absorbing glass

filters used for range changing in optical pyrometers can also be cali- brated as special tests.

References — Radiation Thermometry

Spectroradiometric Determination of

the Freezing Temperature of Gold,

K. D. Mielenz, R. D. Saunders and

J. Shumaker, J. Res. Natl. Inst. Stand. Technol., Vol. 95 (Jan.-Feb.

1990).

The International Temperature Scale

of 1990 (ITS-90), H. Preston- Thomas, Metrologia 27, 3-10

(1990).

69
NBS Measurement Services: Radi- ance Temperature Calibrations,

W. R. Waters, J. H. Walker, and

A. T. Hattenburg, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-7 (Oct.

1987).

The International Practical Temperature Scale of 1968, Amended Edition of 1975, Metrologia, 12, 7

(1976).

Corrections in Optical Pyrometry and

Photometry for the Refractive In- dex of Air, W. R. Blevin, Metrologia, 8, 146 (1972).

Vacuum Tungsten Strip Lamps with

Improved Stability as Radiance

Temperature Standards, T. J. Quinn and R. D. Lee, 5th Symposium on Temperature, 395, Instr. Soc. Am., Res. Triangle Park, NC

(1971).

High-Accuracy Spectral Radiance

Calibration of Tungsten-Strip

Lamps, H. J. Kostkowski, D. E. Erminy, and A. E. Hattenburg, Adv.

Geophys. 14, 111 (1970).

The NBS Photoelectric Pyrometer

and Its Use in Realizing the Inter- national Practical Temperature

Scale above 1063 °C, R. D. Lee,

Metrologia, 2, No. 4, 150 (Oct.

1966).

Theory and Methods of Optical Pyrometry, H. J. Kostkowski and

R. D. Lee, Natl. Bur. Stand. (U.S.),

Monogr. 41 (Mar. 1962).

70
360 lOCHumidity Measurements

Technical Contacts:

Peter H. Huang

Tel: 301/975-2621,2626 James R. WhetstoneTel: 301/975-2738

Mailing Address: A303 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, B349

Physics, Gaithersburg, MD 20899-0001

Test No. Items 36010C Dew-Point Hygrometers ( + 25 to - 15 °C)

36020C Dew-Point Hygrometers ( - 70 to - 15 °C)

36030C Electric Hygrometers

36040C Electrolytic Hygrometers

36050C Aspirated Hygrometers

36060C Pneumatic Bridge Hygrometers

36070S Special Tests of Humidity

Hygrometers (36010C-36060C)

NIST provides calibration services for a wide variety of humiditymeasuring instruments. Calibrations are performed by subjecting the in- strument under test to atmospheres

of known moisture content produced

by the NIST two-pressure humidity

generator. The instruments and

ranges of calibration are listed below:

A. Dew-Point Hygrometers cali- brated over the dew/frost range

of -70 to -l-60°C.

B. Electric Hygrometers classified under this category are sensors which

sorb water vapor as a function of rel- ative humidity; associated with this sorption is a corresponding change in an electric parameter (that is, resis- tance, capacitance). The range of

calibration is 3 to 98 percent relative humidity over the temperature range

-55 to -f-60°C. C. Psychrometers are wet-dry bulb

hygrometers (aspirated psychrometers). The contact person should be

consulted for the special features of

the psychrometer which are necessary before the instrument can be cali- brated at NIST.

D. Electrolytic Hygrometers are

devices which electrolyze water into gaseous oxygen and hydrogen by the

application of a voltage in excess of

the thermodynamic decomposition

voltage for water, and then measure

the electrolysis current. The range

of calibration is 1 to 31,000 ppm by

volume.

E. Pneumatic Bridge Hygrometers

are instruments that measure the

variation of the pressure drop across two combinations of nozzles, operating at critical flow, with a desiccant

between one pair of nozzles. The

range of calibration in mixing ratio (grams of water vapor/grams of dry

air) is 0.0005 to 0.015. Table 3 illustrates typical NIST

uncertainties for measurement of

humidity standards with atmospheric

air at atmospheric pressures.

71
36010C-36070S

Special Tests of Humidity (36070S)

Tests for response time, hysteresis,

and stability can be provided upon re- quest.

Table 3: NIST Two-Pressure Humidity Generator, Mark 2, Range and Uncertainty

Humidity Parameter Range Uncertainty*

iVilAlUg lallU, < J.U /C Ul Value

rw(g water vapor/ 0.0015 <; rw < 0.005 1.5% of value kg dry air) 0.005 <: rw < 0.1 1.0% of value

0.1 <: rw < 0.3 0.5% of value

0.3 <: rw < 155 0.3% of value

Volume ratio, 1

<: V < 3 3.0% of value V (ppm) 3

<; V < 10 1.5% of value 10 <: V < 170 1.0% of value 170 V < 500 0.5% of value 500 <: V < 250,000 0.3% of value

Dew point tem- -80 <: Td < -70 0.2 °C

perature, Td °C -70 <: Td < -35 0.1 °C

-35 <: Td < +60 0.04 °C

Relative humidity, -55 $ Tc < -40 3-98 1.5%

RH (%) at test -40 <: Tc < -20 3-98 0.8%

chamber tem- -20 <: Tc < 0 3-98 0.4%

perature, Tc(°C) 0 Tc < -1-60 3-98 0.2%

*The estimated bounds to systematic error plus three times the standard

deviation.

References — Humidity Measurements

Vapor Pressure Formulation for Ice, A. Wexler, J. Res. Natl. Bur.

Stand. (U.S.), 81A (Phys. and

Chem.), No. 1, 5 (Jan.-Feb. 1977).

The NBS Two-Pressure Humidity

Generator, Mark 2, S. Hasegawa

and J. W. Little, J. Res. Natl. Bur.

Stand. (U.S.), 81A (Phys. and

Chem.), No. 1, 81 (Jan.-Feb. 1977).

Vapor Pressure Formulation for Water in Range 0 to 100 °C, A revi- sion, A. Wexler, J. Res. Natl. Bur.

Stand. (U.S.), 80A (Phys. and

Chem.), Nos. 5 and 6, 775 (Sept. - Dec. 1976).

A Correlation for the Second Interaction Virial Coefficients and Enhancement Factors for Moist Air, R. W. Hyland, J. Res. Natl. Bur.

Stand. (U.S.), 79A (Phys. and

Chem.), No. 4, 551 (July-Aug.

1975).

J. Res. Natl. Bur. Stand. (U.S.), 79A,

(Phys. and Chem.), No. 4, 551

(July-Aug. 1975).

The NBS Standard Hygrometer,

A. Wexler and R. W. Hyland, Natl. Bur. Stand. (U.S.), Monogr. 73

(May 1964).

72
36510S

Total Heat Flux Gauges

Technical Contact:

Kenneth D. Steckler

Tel: 301/975-6678

Mailing Address: A345 Polymers, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 36510S Special Tests of Total Heat Flux Gauges

Special Tests of Total Heat Flux

Gauges (36510S)

NIST is offering a new special test service for total heat flux gauges used

in fire experiments and standard fire tests. A substitution technique is used to calibrate heat flux gauges in an in- frared radiation field at flux levels to nominally 4 W/cml The radiant field

is produced by a stable infrared electric heater. A reference radiometer is used to establish the flux level at the

measurement point within the radiative field. A precision traversing car- riage allows the rapid substitution of

a heat flux gauge for the reference

radiometer at the measurement position.

Current fixtures accommodate 2.54 cm diameter Garden or SchmidtBoelter total heat flux gauges that have coolant tubes emanating from

their rear surfaces. Fixtures for other

geometries can be fabricated at an

additional cost. Each heat flux gauge is calibrated

at four flux levels which span the

range 0.5-3.5 W/cml Accuracy of the

reference radiometer is within 3 per- cent over the range 1 mW/cm^ to 0.9 W/cm^ Based on assumptions of lin- earity of the standard flux gauges and

system uncertainties we expect overall accuracy of within 5 percent for the

calibration range. The special test results are pre- sented in a Report of Test which in- cludes a plot of the measured

incident flux (W/cm^) versus the measured response of the sensor (mV) at each of the four flux levels. The heat

flux sensor will be calibrated and re- turned within 30 days of receipt of

the device and purchase order.

73
Chapter

A Photometric Measurements

B Spectrophotometric Measurements

Q Radiometric Measurements

Q Radiometric Standards in the Far

Ultraviolet E Laser Power and Energy
3701 OC-371 80S

Jonathan E. Hardis George Eppeldauer

Tel: 301/975-2373 Tel: 301/975-2338

Mailing Address: B306 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 37015C Luminous Intensity Rental Piogram

37025C Luminous Intensity-Submitted Lamp

37035C Color Temperature Determination on Lamp

Submitted for 37025C

37080S Special Tests for Luminous Flux of

Incandescent Lamps

37140C Airway Beacon Lamps for Color Temperature

(500 W, 1 point in range, 2000-3000 K)

37150C Each additional color temperature

37160C Color temperature equation (4 points and

interpolation equation)

37170C Opal Glass Luminous Directional Transmittance

Standards

371 SOS Special Photometric Tests

General Information

Calibration services in this area provide access to the photometric scales realized and maintained at NIST.

Lamp standards of luminous intensity,

luminous flux, and color temperature

as described below are calibrated on

a routine basis.

Luminous Intensity Rental Program

(37015C)

NIST will supply to the customer two

500-watt and one 300-watt luminous

intensity lamps. These are inside- frosted bulb lamps with a C-13B

tungsten filament and a medium

bipost base. The luminous intensity of

the lamps will be measured before

and after the customer uses them and

the data furnished to the customer

for determining their calibration base

in luminous intensity. The lamps will be calibrated at a color temperature

of 2856 K. An additional calibration

point at an approximate color temperature of 2700 K will be furnished

for the 500-watt lamps. The approximate 3-sigma uncertainty of these cal- ibrations is 1 percent relative to the

SI units of luminous intensity and 0.8 percent relative to NIST standards.

Luminous Intensity-Submitted

Lamps (37025C)

Lamps that were furnished by NIST

prior to October 1, 1986 as calibrated

standards will be recertified with re- spect to NIST standards and returned

to the customer with a calibration re- port specifying the luminous intensity

of the lamp. Customer supplied lamps

of types other than those traditionally

issued by NIST will be accepted for calibration subject to a determination

as to suitability. Customers should

contact NIST before submitting such

lamps. The approximate 3-sigma uncertainty of these calibrations is 1 percent relative to the SI units of lu- minous intensity and 0.8 percent relative to NIST standards.

Color Temperature Determination on Lamps Submitted for 37025C

(37035C)

The color temperature for given operating conditions will be measured and

furnished for lamps submitted for lu- minous intensity testing on test 37025C. The uncertainty of these cali- brations ranges from 10 K at a color

temperature of 2000 K to 15 K at a color temperature of 3000 K.

75
Special Tests for Luminous Flux of

Incandescent Lamps (37080S)

NIST will calibrate the luminous flux (geometrically total) of customer supplied lamps. These lamps must be

base-up burning and rated at 120 V

for operation. General purpose gas

filled lamps in the range of 60 to 500

watts can be accommodated for test- ing. Approximate 3-sigma uncertainties are 1.4 percent relative to SI

units and 1.2 percent relative to NIST

standards. Customers should contact NIST prior to sending lamps to obtain schedule and price information.

Airway Beacon Lamps

(37140C-37160C)

Color temperature standard lamps

supplied by NIST (airway beacon

500-W medium bipost lamps) are cali- brated for color temperature in the

range 2000 to 3000 K with 3-sigma

uncertainties ranging from 10 to 15 degrees.

Opal Glass Luminous Directional

Transmittance Standards (37170C)

Flashed opal glasses, 51 mmx51 mm,

are calibrated for luminous directional transmittance (exitant lumi- nance per incident illuminance). The

glasses are masked with a diaphragm

limiting the useful area to a circle 1.9 cm in diameter.

Special Tests of Photometric Devices

(37180S)

Lamp standards of luminous intensity can be calibrated at any color temperature in the range 2000 K to 3200 K. Photometric values can be

computed for special sources measured spectrally on the Facility for Automatic Spectral Calibrations

(FASCAL). See test 39060S for details.

Reference— Photometric Measurements

NBS Measurement Services: Photometric Calibrations, R. L. Booker

and D. A. McSparron, Natl. Bur.

Stand. (U.S.), Spec. Publ. 250-15

(Oct. 1987).

76
38010C-38100S

Spectrophotometric Measurements

Technical Contact:

p. Yvonne Barnes

Tel: 301/975-2345

Mailing Address: B306 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 38010C Spectral Transmittance Filters (Cobalt Blue Glass)

38020C Spectral Transmittance Filters (Copper Green Glass)

38030C Spectral Transmittance Filters (Carbon Yellow Glass)

38040C Spectral Transmittance Filters (Selenium Orange

Glass)

38050C Wavelength Standards (Holmium Oxide Glass)

38060S Special Tests of Spectral Transmittance and

Reflectance 38070M Measurement Assurance Program for

^ Retroreflectance — Complete Package

I 38071M Retroreflectance MAP — Sheeting Standards or

II Prismatic Standard with Colored Filters

i' 38072M Retroreflectance MAP-Sheeting Standards and

Prismatic Standard without Colored Filters

j!j 38073M Retroreflectance MAP — Sheeting Standards or

I'! Prismatic Standard without Colored Filters 38074M Retroreflectance MAP -Colored Filters Only

38080M Measurement Assurance Program for Transmittance

38090S Special Tests of X-Ray and Photographic Step

Tablets 38100S Special Tests of Microcopy Resolution Test Charts

Spectral Transmittance Filters (38010C-38040C)

NIST supplies standards of spectral

transmittance for checking the photometric scale of spectrophotometers.

These are either 30 mm polished

glass disks or 51 mm polished glass squares, 2 to 3 mm thick, designated

as cobalt blue, copper green, carbon

yellow, and selenium orange. The total uncertainty ranges from approximately 0.3 to 0.5 percent of the value

at the 3ct level. Information provided

to the user includes values of trans- mittance at 25 °C at 10 nm intervals from 380 to 770 nm, the estimated

uncertainty of each value, and data as

to the effect of temperature change

on transmittance at each wavelength.

Wavelength Standards (38050C)

Holmium oxide glass standards are

also supplied for checking the ultravi- olet and visible wavelength calibra- tions of recording spectrophotometers

having a bandpass less than 2 nm. These are made of polished Corning

3130 glass, 51 x51 mm, 2.5 mm thick. A table of wavelengths of minimum

transmittance is provided in the re- port to the user. The uncertainty is 0.5 nm at the 3ct level.

Special Tests of Spectral Transmittance and Renectance (38060S)

Measurements of spectral transmit- tance can be made for the wavelength

region 190 to 2500 nm. Measurements

of absolute spectral reflectance fac- tors and of spectral specular reflec- tance can be made for the wavelength

region 250 to 2500 nm. However, ar- rangements for these measurements

on submitted specimens must be

made before shipment. The decision

as to whether or not to perform the

measurements and selection of the in- struments to be used will rest with

NIST. Specimens not accepted for measurement will be returned. Accuracy and precision estimates will be

given. Estimates will be dependent

upon the optical characteristics of the

submitted specimens and whether a primary or transfer instrument is used

to perform the measurement.

77
Measurement Assurance Programs

for Retroreflectance (38070M38074M)

These Measurement Assurance Pro- grams (map's) verify, within certain

Hmits, how well a laboratory can measure coefficient of luminous intensity.

The verification is accomplished by means of a MAP package. The MAP

package contains two white bead

sheeting retroreflectors, one colorless prismatic retroreflector, and seven

colored glass filters. The elements in this package are measured by NIST,

then by the participating laboratory,

and finally by NIST. Quality control

procedures are maintained by using

NIST master standards.

The use of three retroreflectors enables determination of how well the

participant can measure coefficient of

luminous intensity for white or colorless samples of three kinds of geometries. The luminous transmittance of

the seven colored glass filters can be

used as a diagnostic tool to check

measurements of coefficient of lumi- nous intensity of colored retroreflectors. This is accomplished by checking

the conformance of the source-receiver combination to CIE Illuminant

A and CIE 2° standard observer re- spectively.

The coefficient of luminous intensity of each of the bead sheeting stan- dards is measured at six combinations

of observation and entrance angles.

The coefficient of luminous intensity

of the prismatic retroreflector is measured at 18 combinations of entrance and observation angles. The luminous

transmittance of the filters is pro- vided only for the spectral conditions

of source and receiver specified

above.

A general testing laboratory will probably need the service utilizing the

complete MAP package. However, some laboratories may be specialized.

For this reason, we list five options

that offer not only the complete package, but also some selected components. These options are the

following:

A. Complete MAP package;

B. Sheeting standards or prismatic standard with colored filters; C. Sheeting standards or prismatic standard without colored filters; D. Sheeting standards and prismatic standard without colored filters; and

E. Colored filters only.

Measurement of even the complete

MAP package achieves only part of

the goal of a MAP service. To fully

benefit from the MAP procedure, we

suggest that the participant have on hand several check standards to be

measured while also measuring the

MAP package. These check standards can then be measured periodically to determine any gross error in measure- ment procedure, and a control chart can be constructed. A control chart is a plot of measurement result versus

time, and normally the measurement

process is considered to be under

control if measurements fall within

±3 standard deviations from the mean. For retroreflectance measure- ments where geometric errors are

large, the standard deviation obtained

after changing geometrical parameters may be large compared with that obtained from repeated measure- ments without changing the apparatus. Thus, the total variation for a given instrument can be obtained only

by repetition over a period of time

and realignment of the experimental

apparatus.

The uncertainties of retroreflec- tometer measurements have three

sources: uncertainties associated with

values assigned by NIST to the MAP

package, participant uncertainties,

and uncertainties due to environment

and sample interaction. Repeated

measurements without changing the

apparatus show that the NIST ran- dom error is small relative to the sys- tematic errors. A large fraction of the

latter arises when the retroreflector is rearranged and realigned for making

measurements with different measurement parameters. The NIST

78
38010C-38100S

uncertainty for retroreflectance measurement ranges from 4 to 15 percent

of the value depending on the geometry and the type of retroreflectors. The NIST uncertainty for luminous

transmittance of the colored glass fil- ters varies up to 0.002 at the 3a level.

Measurement Assurance Program for Transmittance (38080M)

The Transmittance Measurement Assurance Program (MAP) provides a means for a laboratory to assess the

accuracy of its spectral transmittance

measurement capabilities. A laboratory that participates in this program

will be sent a package of trans- mittance filters, which have been

measured at NIST. These are to be

measured by the laboratory on its spectrophotometer(s) and returned,

together with the measurement results, to NIST. NIST will then remeasure the filters and send a final analysis of the result to the participating laboratory. The range of filter measurements provided in the MAP

package permits an evaluation of the

accuracy of a laboratory's spectral

transmission measurements and will often reveal the cause of any systematic errors that exist. The NIST uncertainty ranges from approximately 0.05 to 0.5 percent of the

value at the 3ct level for filters with

nominal transmittance from 0.92 to 0.001. The MAP package includes seven

neutral density filters with nominal

transmittances ranging from 0.92 to 0.001. The filters are available in three sizes. The filter holders are 51x51 mm, 51 x 38 mm, or standard

cuvette. In addition, the package contains one didymium glass filter or cu- vette-sized holmium oxide solution

that is to be used for wavelength

scale calibration. Several wavelengths

of transmittance minima and points

of inflection have been measured by

NIST for the didymium filter. These

wavelengths have been shown to be

stable over long periods of time;

therefore, these didymium filters are

not normally measured by NIST with every use of the MAP package. The

didymium filter is useful for triangular bandpasses between 1.5 and 10.5 nm with an uncertainty up to 0.3 nm. The holmium oxide solution has been

certified at several wavelengths for bandpasses up to 3.0 nm with an uncertainty of 0.1 nm.

It is strongly suggested that the

participating laboratory acquire a set of check standards similar to the

NIST filters for maintaining a control

chart and measurement assurance.

Special Tests of X-Ray and

Photographic Step Tablets (38090S)

Special tests for visual transmission of

density ranges from 0 to 4 (by inte- grating sphere or by opal glass dif- fuser) and reflection optical density can be performed by prior arrange- ment. Tablets submitted must be free of scratches, fingerprints, abrasions,

and foreign matter and must have

steps of uniform density. The visual transmission density is measured in accordance with ANSI Standard

PH2.19/ISO 5/2-1986 with an uncertainty of the greater of 0.01 or 1 per- cent of the value. The visual reflection density of 4570° is measured in accordance with ANSI Stan- dard PH2.17/ISO 5/4-1985 with an

uncertainty of the greater of 0.02 or 2 percent of the value.

Special Tests of Microcopy Resolution

Test Charts (38100S) Test charts conforming to ISO Stan- dard 3334, NMA Standard MS104-

1972, and MIL-M-9868D, can be

tested by special arrangement.

References — Spectrophotometric

Measurements

National Scales of Spectrometry in the U.S., J. J. Hsia, Advances in Standards and Methodology in Spectrophotometry 1987, Elsevier

Science Publishers, B. V., Amsterdam, pp. 99-109 (1987).

79
NBS Measurement Services: Spectral

Reflectance, V. R. Weidner and

J. J. Hsia, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-8 (July 1987).

NBS Measurement Services: Regular

Spectral Transmittance, K. L. Eckerle, J. J. Hsia, K. D. Mielenz,

and V. R. Weidner, Natl. Bur.

Stand. (U.S.), Spec. Publ. 250-6

(July 1987).

White Opal Glass Diffuse Spectral

Reflectance Standards for the Visi- ble Spectrum (SRM's 2015 and

2016), V. R. Weidner, Nafl. Bur.

Stand. (U.S.), Spec. Publ. 260-82

(1983).

Extension of a Reference Spectrophotometer into the Near Infrared, K. L. Eckerle, V. R. Weidner, J. J. Hsia, and Z. W. Chao, Nali. Bur.

Stand. (U.S.), Tech. Note 1175

(Apr. 1983).

Measurement Assurance Program —

Transmittance Standards for Spectrophotometric Linearity Testing:

Preparation and Calibration, K. L. Eckerle, V. R. Weidner, J. J. Hsia,

and K. Kafadar, J. Res. Nafl. Bur.

Stand. (U.S.), 88(1), 25 (1983).

Second-Surface Mirror Standards of

Spectral Specular Reflectance

(SRM's 2023, 2024, 2025), J. C. Richmond, J. J. Hsia, V. R. Weidner, and D. B. Wilmering, Natl. Bur. Stand. (U.S.), Spec. Publ.

260-79 (Oct. 1982).

Proposed Standards for the NBS

Retroreflectance MAP, K. L. Eckerle and J. J. Hsia, Color Res. and Appl., 7(3), 235 (1982).

NBS 45°/Normal Reflectometer for Absolute Reflectance Factors, J. J. Hsia and V. R. Weidner, Metrologia, 17, 97 (1981).

NBS Specular Reflectometer — Spectrophotometer, V. R. Weidner and

J. J. Hsia, Appl. Opt., 19, 1268

(Apr. 1980).

New Reference Retroreflectometer,

K. L. Eckerle, J. J. Hsia, V. R.

Weidner, and W. H. Venable, Jr., Appl. Opt., 19(8), 1253 (1980).

Photometry and Colorimetry of

Retroreflection: State-of-Measurement Accuracy Report, K. L. Eckerle, Nafl. Bur. Stand. (U.S.),

Tech. Note 1125 (July 1980).

Inverse-Fourth Apparatus for Photometric Calibrations, D. A. Swyt and

J. G. LaRock, Rev. Sci. Instrum.,

49(8), 1083 (Aug. 1978).

Basic Considerations of Densitometer

Adjustment and Calibration, R. E. Swing, Natl. Bur. Stand. (U.S.),

NBSIR 75-682 (Feb. 1975).

Establishing a Scale of DirectionalHemispherical Reflectance Factor

1: The Van den Akker Method,

W. H. Venable, Jr., J. J. Hsia, and

V. R. Weidner, J. Res. Natl. Bur.

Stand. (U.S.), 82, 1, 29 (July-Aug.

1977).

New Reference Spectrophotometer,

K. D. Mielenz, K. L. Eckerle, R. P. Madden, and J. Reader,

Appl. Opt., 12, 7, 1630 (July 1973).

The Optics of Densitometry, R. E. Swing, Opt. Eng., 12, 6, 185

(Nov.-Dec. 1973).

Basic Considerations of Densitometer

Adjustment and Calibration, R. E. Swing, Natl. Bur. Stand. (U.S.),

Report 10970 (Dec. 1972).

Permanence of Glass Standards of

Spectral Transmittance, K. S. Gibson and M. A. Belknap, J. Res.

Natl. Bur. Stand. (U.S.), 44, 463

(May 1950).

80
39010C-39080S

Radiometric Measurements

Technical Contacts:

John K. Jackson 39010C-39060S

Tel: 301/975-2330

Chris L. Cromer

39070C-39080S

Tel: 301/975-3216

Thomas C. Larason 39070C-39080S

Tel:30 1/975-2334

Sally S. Bruce 39070C-39080S

Tel: 301/975-2323

Mailing Address: A221 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 39010C Spectral Radiance Ribbon Filament Lamps (225 to 2400 nm)

39020C Spectral Radiance Ribbon Filament Lamps (225 to 800 nm)

39030C Spectral Radiance Ribbon Filament Lamps (650 to 2400 nm)

39040C Spectral Irradiance Quartz-Halogen Lamps (250 to 1600 nm)

39045C Spectral Irradiance Quartz-Halogen Lamps (250 to 2400 nm)

39050C Spectral Irradiance Deuterium Lamps (200 to 350 nm)

39060S Special Tests of Radiometric Sources 39070C Photodiode Spectral Response Rental Package

39080S Special Tests of Radiometric Detectors

Spectral Radiance Ribbon Filament

Lamps (39010C-39030C)

These spectral radiance standards are supplied by NIST. Tungsten, ribbon

filament lamps (30A/T24/13) are pro- vided as lamp standards of spectral

radiance. The lamps are calibrated at 34 wavelengths from 225 to 2400 nm,

with a target area 0.6 mm wide by 0.8 mm high. Radiance temperature

ranges from 2650 K at 225 nm, and

2475 K at 650 nm to 1610 K at 2400

nm, with corresponding uncertainties

of 2, 0.6, and 0.4 percent. For spectral radiance lamps, errors are stated

as the quadrature sum of individual

uncertainties at the three standard

deviation level. See also related tests 40010C-40040S, next section. Figure 7 summarizes the measure- ment uncertainty for NIST spectral

radiance calibrations.

Figure 7. Uncertainties for NIST Spectral Radiance

Calibrations

500

03Q.

0)c

o

CO c

<DO

C

Z)

•D

<D {5E

200

100 -

0.1 0.2 0.4 0.6 1 2

Wavelength in Micrometers

Spectral Irradiance Lamps

(39040C-39050C)

These spectral irradiance standards

are supplied by NIST. Lamp stan- dards of spectral irradiance are pro- vided in two forms. Tungsten

filament, 1000-watt quartz halogen

type FEL lamps are calibrated at 31

wavelengths in the range 250 to 2400 nm. At the working distance of 50

cm, the lamps produce 0.2 W/cm^ at 250 nm, 220 W/cm^ at 900 nm, 115

W/cm' at 1600 nm, and 40 W/cm^ at 2400 nm, with corresponding uncertainties of 2.2, 1.3, 1.9, and 6.5 percent. For spectral irradiance lamps,

errors are stated as the quadrature sum of individual uncertainties at the

three standard deviation level. Deuterium lamp standards of spectral ir- radiance are also provided and are

calibrated at 16 wavelengths from 200

to 350 nm. At the working

81
39010C-39080S

distance of 50 cm, the spectral irradi- ance produced by the lamp ranges

from about 0.5 W/cm^ at 200 nm and

0.3 WW at 250 nm to 0.07 W/cm^ at 350 nm. The deuterium lamps are in- tended primarily for the spectral re- gion 200 to 250 nm. The approximate

uncertainty relative to SI units is 7.5 percent at 200 nm and 5 percent at 250 nm. The approximate uncertainty

in relative spectral distribution is 3 percent. It is strongly recommended

that the deuterium standards be compared to an FEL tungsten standard over the range 250 to 300 nm each

time the deuterium lamp is lighted to take advantage of the accuracy of the

relative spectral distribution. Figure 8 summarizes the measure- ment uncertainty for NIST spectral ir- radiance calibrations of type FEL

lamps.

Figure 8. Uncertainties for NIST Spectral Irradiance

Calibrations of Type FEL Lamps

1—

r

0.1 0.2 0.4 0.6 1 2 4 6 Wavelength in Micrometers

Special Tests of Radiometric Sources

(39060S)

Spectroradiometric source calibra- tions are performed on the Facility for Automatic Spectral Calibrations

(FASCAL). This instrument has the

capability of performing spectral radi- ance measurements from 200 to 2500

nm, radiance temperatures from

1050 K to 2700 K, and adjustable

spectral bandpass down to 0.1 nm.

Spectral irradiance measurement capability from 200 to 2400 nm at flux

levels down to 0.1 W/cm^ is also avail- able. For both spectral radiance and

irradiance measurements a wide vari- ety of sources and measurement ge- ometries are possible. Special tests utilizing the capabilities of FASCAL

are occasionally performed depending on the availability of the equipment

and associated personnel.

Photodiode Spectral Response Rental

Package (39070C)

Photodiode response packages can be

rented from NIST. Absolute spectral

responsivity calibrations can be obtained by leasing one of the NIST

Detector Response Transfer and In- tercomparison Packages. This is a well-characterized radiometer that

utilizes a silicon photodiode as the

detector element. Its calibration is re- ported in units of AAV at a number

of wavelengths in the 200 to 1100 nm

range. A precision aperture is pro- vided for calibrations in units of A

cm^AV. The duration of the lease is sufficient to enable the transfer of the

calibration to a laboratory's own in- house standards. This calibration is based on an electrically calibrated

high accuracy cryogenic radiometer.

The absolute spectral response is re- ported at 5 nm intervals from 200 to 1100 nm. The estimated uncertainty

ranges from 0.3 to 1 percent, depending on the wavelength. The radiometers cover a range of detector current from 10"" to 10"^ A. This corre- sponds to a radiant power range of

about 1 pW to 1 mW.

82
Special Tests of Radiometric

Detectors (39080S)

Special tests of radiometric detectors

generally used in the ultraviolet, visi- ble, and infrared regions of the spec- trum can be performed. Responsivity can be measured on detectors between 200 to 1800 nm at power levels of less than 10 |xW. Examples of detector characteristics that can be determined in a special test include

spectral response (A/W), quantum ef- ficiency (electrons/photon), linearity,

and uniformity (over surface area).

Since special tests of this type are unique, details of the tests should be

discussed with C. Cromer prior to submitting a formal request. Also,

characterized silicon detectors can be

purchased from NIST that are cali- brated in either the 200 to 450 nm or 400 to 1100 nm regions in 5 nm steps.

Jeanne Houston and Christopher Cromer are aligning in the detector calibration facility.

References — Radiometric Measurements

Spectroradiometric Determination of

the Freezing Temperature of Gold,

K. D. Mielenz, R. D. Saunders and

J. Shumaker, J. Res. Natl. Inst. Stand. Technol., Vol. 95 (Jan-Feb.

1990).

39010C-39080S

The International Temperature Scale

of 1990 (ITS-90), H. Preston- Thomas, Metrologia 27, 2-310

(1990).

NBS Measurement Services: The

NBS Photodetector Spectral Response Calibration Transfer Pro- gram, E. F. Zalewski, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-17

(1988).

NBS Measurement Services: Spectral

Irradiance Calibrations, J. H.

Walker, R. D. Saunders, J. K. Jackson, and D. A. McSparron, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-

20 (Sept. 1987).

NBS Measurement Services: Spectral

Radiance Calibrations, J. H.

Walker, R. D. Saunders, and A. T. Hattenburg, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-1 (Jan.

1987).

Spectral Response Self-Calibration

and Interpolation of Silicon Photodiodes, J. Geist, E. F. Zalewski,

and A. R. Schaefer, Appl. Opt. 20,

3795 (1980).

Spectral Irradiance Standard for the

Ultraviolet: The Deuterium Lamp,

R. D. Saunders, W. R. Ott, and

J. M. Bridges, Appl. Opt. 17, 593

(1978).

The 1973 NBS Scale of Spectral Irra- diance, R. D. Saunders and J. B. Shumaker, Natl. Bur. Stand. (U.S.),

Tech. Note 594-13 (1977).

Spectral Radiometry: A New Approach Based on Electro-Optics,

J. Geist, M. A. Lind, A. R.

Schaefer, and E. F. Zalewski, Natl. Bur. Stand. (U.S.), Tech. Note 954

(1977).

Fundamental Principles of Absolute

Radiometry and the Philosophy of

This NBS Program (1968 to 1971),

J. Geist, Natl. Bur. Stand. (U.S.),

Tech. Note 594-1 (1972).

High-Accuracy Spectral Radiance

Calibration of Tungsten-Strip

Lamps, H. J. Kostkowski, D. E. Er- miny, and A. T. Hattenburg, Adv.

Geophys., 14, 111 (1970).

83
40010C-40040S

D Radiometric Standards in the Far Ultraviolet

D.l Standard Sources

Technical Contact:

Mervin Bridges

Tel: 301/975-3228

Mailing Address: A167 Physics, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 40010C Spectral Irradiance Standard, Argon Mini-Arc

(140 to 330 nm)

40020C Spectral Radiance Standard, Argon Mini-Arc

(115 to 330 nm)

40030C Spectral Irradiance Standard, Deuterium Arc Lamp

(165 to 200 nm)

40040S Special Tests of Radiometric Devices in the Near and

Vacuum Ultraviolet

Source Calibrations in the Ultraviolet

(40010C^0040S)

NIST maintains a collection of sec- ondary standard sources such as ar- gon maxi-arcs, argon mini-arcs, and

deuterium arc lamps in the near and vacuum ultraviolet radiometric stan- dards program to provide calibrations

for user-supplied sources. The cali- brations of these sources are trace- able to a hydrogen arc whose

radiance is calculable and which

NIST maintains as a primary stan- dard. The collection also includes

tungsten strip lamps and tungsten

halogen lamps whose calibrations are based on a blackbody rather than a hydrogen arc. Customer-supplied

sources are calibrated in both radi- ance and irradiance by comparing

them with NIST secondary standards.

Argon arcs are used to calibrate

other sources in the wavelength range

115 nm to 330 nm for radiance and

140 nm to 330 nm for irradiance. The

lower wavelength limit is determined

in radiance by the cutoff of the magnesium fluoride windows used in the

arcs and in irradiance by the decrease

in signal produced by the addition of

a diffuser. Deuterium arc lamps are used in the range 165 nm to 200 nm,

with the low wavelength cutoff due to the onset of blended molecular lines. The high wavelength limit is the start- ing point of the range of another cali- bration group at NIST. (See tests 39010C-39050C, previous section.)

The tungsten lamps are used at 250

nm and above, since their signals are too weak at shorter wavelengths. It should be noted that the wavelength

range of the NIST arcs partially overlaps the range of tungsten lamps, thus

providing an independent check on

calibrations. An argon mini-arc lamp supplied

by the customer is calibrated for spectral irradiance at 10-nm intervals in the wavelength region 140 to 300 nm.

Absolute values are obtained by comparison of the radiative output with

laboratory standards of both spectral

irradiance and spectral radiance. The

spectral irradiance measurement is made at a distance of 50 cm from the

field stop. Uncertainties are esti- mated to be less than ± 10 percent in the wavelength region 140 to 200 nm

and within ±5 percent in the wavelength region 200 to 330 nm. A measurement of the spectral transmission

of the lamp window is included in or- der that the calibration be independent of possible window deterioration or damage. The uncertainties given

here and below are taken to be two

standard deviations (2a), i.e., as having a confidence limit of about 95

percent.

The spectral radiance of argon

mini-arc radiation sources is determined to within an uncertainty of less than 7 percent over the wavelength

range 140-330 nm and 20 percent over

the wavelength range 115 to 140 nm.

84
40010C-40040S

The calibrated area of the 4-mm di- ameter radiation source is the central 0.3-mm diameter region. Typical val- ues of the spectral radiance are: at 250 nm, U= 30 mW cm"^ nm"' sr"'; and at 150 nm, Lx = 3 mW cm"^ nm~'

sr~^ The transmission of the demountable lamp window and that of an additional MgF2 window are deter- mined individually so that the user may check periodically for possible

long-term variations. The deuterium arc lamp is cali- brated at 10 wavelengths from 165 to 200 nm, at a distance of 50 cm. Typical values of spectral irradiance are

0.5 W/cm' at 165 nm, 0.3 W/cm^ at 170 nm, and 0.5 W/cm^ at 200 nm. The approximate uncertainty relative

to SI units is estimated to be less than 10 percent. The lamp is nor- mally supplied by NIST and requires

300 mA at about 100 V.

References — Source Calibrations in the Ultraviolet

Radiometric Calibrations of Portable

Sources in the Vacuum Ultraviolet,

J. Z. Klose, J. M. Bridges, and W. R.

Ott, J. Res. Natl. Bur. Stand. (U.S.),

93, 21 (1988).

NBS Measurement Services: Radiometric Standards in the Vacuum Ultraviolet, J. Z. Klose, J. M. Bridges,

and W. R. Ott, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-3 (June

1987).

Radiance of a Pt/Cr-Ne Hollow

Cathode Spectral Line Source,

J. Z. Klose and J. M. Bridges,

Appl. Opt., 26, 5202 (1987).

VUV Spectral Irradiance Calibrations: Method and Applications,

W. R. Ott, J. M. Bridges, and J. Z. Klose, Opt. Lett., 5, 225 (1980).

Spectral Irradiance Standard for the

Ultraviolet: The Deuterium Lamp,

R. D. Saunders, W. R. Ott, and

J. M. Bridges, Appl. Opt., 17, 593

(1978).

Spectral Radiance Calibrations between 165-300 nm: An Interlaboratory Comparison, J. M. Bridges, W.

R. Ott, E. Pitz, A. Schultz,

D. Einfield, and D. Stuck, Appl.

Opt., 16, 1788 (1977).

VUV Radiometry, 3: The Argon

Mini-Arc as a New Secondary Stan- dard of Spectral Radiance,

J. M. Bridges and W. R. Ott, Appl.

Opt., 16, 367 (1977).

NBS UV Radiometric Standards,

W. R. Ott, Natl. Bur. Stand. (U.S.),

Spec. Publ. 456, 107 (1976).

85
40510C-40599S

D. Radiometric Standards in ttie Far Ultraviolet

D.2 Standard Detectors in the

Far Ultraviolet

Technical Contact:

L. Randall

Canfield

Tel: 301/975-3728

Mailing Address: B119 Radiation Physics. National

Institute of Standards and Technology, Gaithersburg, MD

20899-0001

Test No. Items 405 IOC Detector Standard, Windowless Photodiode

(5 to 122 nm)

40511C Recalibration of Detector Standard (5 to 122 nm)

40520C Detector Standard, Windowless Photodiode

(18 to 122 nm)

40521C Recalibration of Detector Standard (18 to 122 nm)

40530C Detector Standard, Windowless Photodiode

(52 to 122 nm)

40531C Recalibration of Detector Standard (52 to 122 nm)

40540C Uncalibrated Windowless Photodiode

40560C Detector Standard, Windowed Photodiode

(116 to 254 nm)

40561C Recalibration of Detector Standard (116 to 254 nm)

40599S Special Tests on Detectors from the Near Ultraviolet (320 nm) to the Soft X-Ray Region (5 nm)

Detector Calibrations in the Ultraviolet (40510C-^0599S)

Calibrated transfer standard detectors

for the far ultraviolet are available

from NIST to cover the spectral re- gion 5 to 254 nm. Users are furnished

with the quantum efficiency as a function of wavelength, with quantum

efficiency defined as the number of

photoelectrons per incident photon.

Three detector types are available to cover this range: (1) a windowless

silicon semiconductor photodiode for

the wavelength region 5-50 nm

(Available Under Test No. 40599S);

(2) a windowless photoemissive diode

with an AI2O3 photocathode for the

wavelength region 5-122 nm; and (3) a MgF2-windowed photodiode with a semi-transparent CsTe photocathode

for the wavelength region 116-254 nm. The detectors have been extensively studied regarding radiometrically important parameters such as photocathode spatial uniformity and

temporal stability of conversion effi- ciency. It should be noted that the

silicon photodiode is not solar blind,

while the windowless photoemissive

diode is. Stray light considerations

should be evaluated before making a choice for the 5-50 nm region.

The probable errors in the measured quantum efficiencies are 8 to 15 percent in the 5- to 122-nm windowless photodiode region and 6 to 10 percent in the 116- to 254-nm windowed photodiode region. Probable

error means that there is a probability

of 0.5 that the true quantum effi- ciency values lie within the stated er- ror range about the values measured.

All calibrations are based on the

rare gas ionization chamber as an absolute detector. In the windowless re- gion 5 to 92 nm, working standards

are calibrated directly against such a

reference, while at longer wavelengths

it is necessary to transfer the calibration derived from the ionization

chamber at shorter wavelengths with

the use of a special uniformly "gray"

thermopile. The shortest portion of

the windowless region involves the use of a beamline at the NIST elec- tron storage ring facility, SURF-II,

while the calibrations above 50 nm

are conducted using plasma light sources in a laboratory environment.

Outgoing detectors are calibrated

by direct intercomparison with precalibrated working standards that are

periodically recalibrated. Windowless

AI2O3 photodiodes are fabricated in- house; the windowless Si photodiodes

and the windowed CsTe photodiodes

are procured commercially and tested

for stability and spatial homogeneity.

86
40510C-40599S

Only those photodiodes meeting

stringent NIST quality specifications are selected as transfer standards.

The calibration costs include the cost of the detector and screening services

unless a recalibration of previously

used detectors is requested.

Special detectors that do not lend

themselves to convenient on-site

cross-calibration may also be cali- brated at NIST if the detectors merit

radiometric application and if the

NIST calibration facilities are suitable

and available for the particular

device.

References — Detector Calibrations in the Ultraviolet

Far Ultraviolet Detector Standards,

L. R. Canfield and N. Swanson,

J. Res. Natl. Bur. Stand. (U.S.), 92,

97 (1987).

NBS Measurement Services: Far Ultraviolet Detector Standards, L. R.

Canfield and N. Swanson, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-

2 (June 1987).

Time Response of NBS Windowless

XUV Radiometric Transfer Standards, E. B. Saloman, Appl. Opt.

14, 1764 (1975).

87
42110C-42180S

£. Laser Power and Energy

Technical Contacts:

) V

Thomas R. Scott

Tel: 303/497-3651 Aaron A. Sanders

Tel: 303/497-5341 Kathy Hillen Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M. C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder,

CO 80303-3328

Test No. Items 42110C Laser Power and Energy Meter Calibrations 42111C Same as 42110C, Additional Wavelengths

or Power Levels 42120M Laser Power and Energy Measurement Assurance Program (MAP)

42130C Optical Fiber Power Meter Calibrations 42131C Same as 42130C, Additional Wavelengths

42140M Optical Fiber Power Meter Measurement Assurance Program (MAP)

42150M Low-Level Laser Measurement Assurance Program

(MAP)

42160C Pulsed 10.6-n.m Laser Calibrations 42170S Special Tests for Laser Power and Energy Meters, by

Prearrangement

42180S Special Tests for Optical Fiber Power Meters, by

Prearrangement

Laser Power and Energy — General

Information

The National Institute of Standards

and Technology develops and maintains the U.S. national standards for the measurement of laser power and

energy. These standards are realized

in the form of several types of iso- peribol (constant temperature environment) calorimeters. The calorimeters compare absorbed laser radiation

to an equivalent quantity of electrical energy. Well-characterized transfer standards (calibrated against the

primary standards) are also maintained as laboratory standards for cal- ibrations and for use in Measurement

Assurance Program (MAP) intercomparisons. The primary standards and

secondary transfer standards are used

in specially designed calibration sys- tems that allow various power and en- ergy meters to be compared to the

standards. Table 4 summarizes the

measurement capabilities of the primary standard measurement systems

and lists typical calibration uncertainties.

Table 4: Primary Standard Measurement Capabilities

Primary Typical

Standard Wavelength Range Power Range Uncertainty

C-series 488.0, 514.5 nm 1 ^JLW - 1 w ±0.5-1.0%

632.8 nm 1 jjlW - 20 mW ±0.5-1.0%

830 nm 100 ixW- 20 mW ±0.5-1.0%

1.06 jjLm 1 mW - 1 W ±0.5-1.0%

1.32 |jLm 100 jjlW - 100 mW ±0.5-1.0%

1.53 [im 100 tiW - 1 mW ±0.5-1.0%

Q-series 1.06 ixm (Q-switched) <110mJ/pulse ±1.1-1.9%

Kl-series 10.6 \xm 1 W - 300 W ±1.6-2.5%

K2-serics 10.6 |j,m 40 mW- 40 W ±2.5-3.5%

Laser Power and Energy Meter

Calibration (42110C-42111C)

Within the ranges listed in Table 4, NIST can perform calibrations at the

power or energy and wavelength

specified by the owner. The instru- ment is sent to NIST where it is then

compared to the appropriate primary

reference calorimeter using a cali- brated beamsplitter measurement sys- tem. Normally, no adjustments are made to the test instrument. At the

completion of the calibration measurements, the instrument and a cali- bration report are sent to the owner. The calibration report summarizes

the results of the measurements and

provides a detailed listing of the asso- ciated measurement uncertainties.

These calibration measurements

are accomplished using a calibrated

beamsplitter arrangement in which

both the standard and the test meter

are exposed to the laser beam

88
42110C-42180S

simultaneously. All the significant

parameters (e.g., electrical calibration

coefficient, absorptivity, window

transmission) for each of the standard

calorimeters used in these measure- ments have been evaluated for each

laser wavelength used. Based on first principles of thermodynamics and lin- ear system analysis, the characteristic

voltage response of the standard

isoperibol calorimeters can be corre- lated to the quantity of energy absorbed. Because the reference

calorimeters measure energy, laser

stability is not required when calibrat- ing other energy detectors. However,

when calibrating power meters, either

a stable laser is used or else the

voltage of the test meter is integrated

to give an energy measurement. The

data acquisition and analysis for these

systems are computer controlled. The laser sources used for these

calibration measurements with the

primary standards consists of the fol- lowing types: (1) helium-neon (632.8

nm), (2) helium-neon (1.53 |xm), (3)

argon ion (488.0 & 514.5 nm), (4)

Nd:YAG (1.064 ixm, cw &

0-switched), (5) Nd:YAG (1.32 \xm),

(6) diode laser (830 nm), and (7) car- bon dioxide (10.6 iJim).

Laser Power and Energy Measurement Assurance Programs (42120M)

The Measurement Assurance Pro- gram (MAP) service is available at the wavelengths and powers listed in Table 4. The laser MAP intercomparisons are implemented by means

of transfer standards which have been

evaluated and characterized relative to the national primary standards.

The measurement system and primary

standards discussed above are used to calibrate the transfer standards for the intercomparisons. The characteristics of these transfer standards are

well understood, and their associated

accuracies do not differ significantly

from those associated with direct comparisons to the primary standards.

For a specified wavelength

and power or energy, the appropriate

transfer standard is selected and sent from NIST to the MAP participant.

The participant calibrates the NIST

transfer standard using his measure- ment system and then returns both

his data and the transfer standard to NIST. Before and after the NIST

transfer standard is shipped to the

participant, NIST performs calibra- tion measurements on the detector to provide continuity during the inter- comparison process. At the completion of the intercomparison sequence,

NIST evaluates the participant's measurement results relative to the NIST

calibration results on this same meter. A MAP intercomparison report is then submitted to the participant

summarizing the intercomparison and

listing the associated measurement

uncertainties.

Optical Fiber Power Meter

Calibrations (42130C-42131C)

Optical fiber power meters are cali- brated using an automated calibration

system in which the test meter and

the laboratory standard are alter- nately exposed to a stable laser source. Table 5 summarizes the cur- rent capabilities of this system. The

laboratory standard used for these

measurements is an electrically cali- brated pyroelectric radiometer

(ECPR), which has been calibrated

against the C-series primary standard

calorimeter. Various laser sources are used to provide collimated beams ap- proximately 3 to 4 mm in diameter

for the optical power meter calibrations.

Table 5: Measurement Capabilities

Laboratory Typical

Standard Wavelength Window Power Range Uncertainties ECPR 850 nm 100 ^JLW ±0.5-1.0%

ECPR 1300 nm 100 ^JLW ±0.5-1.0%

ECPR 1550 nm 100 M.W ±0.5-1.0%

89
42110C-^2180S

Optical Fiber Power Meter

Measurement Assurance Program

(MAP) (42140M)

NIST maintains a set of calibrated

transfer standards that are available

for MAP intercomparisons of optical

fiber power meters. These transfer standards are calibrated using the optical fiber power meter calibration

system discussed above at the wavelengths listed in table 5.

John B. Schlager uses soliton-like compression in the generation of very short

pulses of light as part of work to measure

the performance of lightwave system components used for optical-fiber telecommunications.

90

Low-Level Laser Measurement

Assurance Program (MAP) (42150M)

NIST has designed and constructed

special silicon and germanium diode

detectors to measure pulse energy

and peak power of low-level,

1.064-^,m laser pulses of about 10- to 100-ns duration. These diode detectors have been evaluated for spatial

uniformity, bandwidth, and linearity,

and are used as transfer standards for intercomparison measurements. The

output response of each detector has

been calibrated against a transfer standard, which, in turn, has been

calibrated against the C-series

calorimeter. The system for calibrat- ing these transfer standards uses a cw Nd:YAG laser beam, which is acousto-optically modulated to pro- duce short, well-defined pulses. The

beam intensity is attenuated to low

levels using a multiple reflection precision wedge beamsplitter. The transfer standards are available for intercomparisons at the levels listed

in table 6.

Table 6: Low-Level MAP Transfer Standards

Transfer Standard Energy/Power Range Typical Uncertainty

Silicon PIN IQ-'^'-lO-" JW/pulse ±8-10%

Germanium PIN lO-'^-lO"'^ JW/pulse ±15%

Silicon APD 10-'*-10-'' W/cm^ (peak) ±9-12%
42nOC-42180S

Pulsed 10.6-fjiin Laser Calibrations

(42160C)

NIST can perform responsivity and

energy calibrations on instruments designed to measure pulsed laser radiation at a wavelength of 10.6 \xm. For

these measurements a transfer stan- dard (calibrated against the K-series

calorimeters) is used in a beamsplitter arrangement in which a trans- versely excited atmospheric pressure (TEA) CO2 laser is used as the radiation source. The TEA laser, sur- rounded by a shielded aluminum

enclosure, is composed of both a high-pressure cell containing the gain

medium (mixture of carbon dioxide,

helium, and nitrogen) and a low-pres- sure gain cell also containing the same gain medium. The low-pressure

cell causes the laser to operate at a

single longitudinal mode (SLM). To

determine responsivity, the output

voltage waveform of the instrument

being calibrated is acquired with a transient digitizer and numerically in- tegrated with a computer. The voltage

integral is then divided by the inci- dent energy as measured by the transfer standard and beamsplitter system.

At the completion of the responsivity or energy measurements, a calibration

report is sent, along with the detector, to the owner. Table 7 summarizes

the capability of this pulsed measure- ment system.

'Table?: Pulsed CO2 Calibrations

Measurement

Pulse Width

Typical Pulse Energy Uncertainty

Responsivity

Energy 200 ns 200 ns

5-60 mJ/pulse (SLM TEM,x.) ± 5-15%

5-300 mJ/pulse (mulli-spatial mode) ±5%

Special tests for Laser Power and

Energy Meters, by Prearrangement

(421 70S) Laser calibrations or measurements

not specifically mentioned above may

be arranged by contacting NIST and

discussing the particular requirements

with the appropriate NIST personnel.

Special-test measurements could in- clude, for example, calibrations at wavelengths or power levels not listed above or other unique measurements

such as impulse response or linearity

measurements. Low-level laser cali- brations are also included in this cat- egory. All these measurements must

be prearranged with NIST.

Special Tests for Optical Fiber Power

Meters, by Prearrangement (42180S)

The special tests in this category in- clude optical fiber power meter measurements not listed above. For

example, this category would be used

for power meters using fiber connectors or meters that have small-area

detectors. All these special-test

measurements must be prearranged

with NIST.

References — Laser Power and Energy

NBS Laser Power and Energy Measurements, T. R. Scott, Proc. SPIE

O-E LASE '88, Optoelectronics

and Laser Applications in Science

and Engineering (1988).

A System for Measuring Energy and

Peak Power of Low-Level 1.064-ixm

Laser Pulses, A. A. Sanders and

A. L. Rasmussen, Natl. Bur. Stand.

(U.S.), Tech. Note 1058 (Oct.

1982).

Documentation of the NBS C, K, and

O Laser Calibration Systems, W. E. Case, Natl. Bur. Stand. (U.S.), NBSIR 82-1676 (Sept. 1982).

A System for Measuring the Characteristics of High Peak Power Detectors of Pulsed CO2 Radiation, P. A. Simpson, Natl. Bur. Stand. (U.S.),

Tech. Note 1023 (Sept. 1980).

91
Quality Assurance Program for the

NBS, C, K, and Q Laser Calibration Systems, W. E. Case, Natl. Bur. Stand. (U.S.), Int. Report,

NBSIR 79-1619 (Aug. 1979).

A System for Calibrating Laser Power

Meters for the Range

5-1000 W., E. D. West and L. B. Schmidt, Natl. Bur. Stand. (U.S.),

Tech. Note 685 (May 1977).

An NBS Measurement Assurance

Program, A. A. Sanders and A. R. Cook, Proc. Electro-Optics Laser

Conference (1976).

Absolute Reference Calorimeter for Measuring High-Power Laser

Pulses, D. L. Franzen and L. B. Schmidt, Appl. Opt. 15, 3115 (Dec.

1976).

A Calorimeter for High-Power CW

Lasers, R. L. Smith, T. W. Russell,

W. E. Case, and A. L. Rasmussen,

IEEE Trans. Instr. Meas., Vol. IM21, No. 4 (Nov. 1972).

A Reference Calorimeter for Laser

Energy Measurement, E. D. West,

W. E. Case, A. L. Rasmussen, and

L. B. Schmidt, J. Res. Natl. Bur. Stand. (U.S.), 76A, No. 1, 13 (Jan.-

Feb. 1972).

Data Analysis for Isoperibol Laser

Calorimetry, E. D. West, Natl. Bur.

Stand. (U.S.), Tech. Note 396 (Feb.

1971).

Theory of Isoperibol Calorimetry for Laser Power and Energy Measurement, E. D. West and K. L. Churney, J. Appl. Phys. 41, No. 6, 2705

(May 1970).

References — Optical Fiber Power

Meter Measurements

Calibrated Optical Fiber Power

Meters: Errors Due to Variations

in Connectors, Xiaoyu Li and

R. L. Gallawa, Fiber & Integrated

Optics, Vol. 7 (Mar. 1988).

Calibration of Optical Fiber Power

Meters: The Effect of Connectors,

R. L. Gallawa and Xiaoyu Li,

Appl. Opt. 26, 1170 (Apr. 1987).

Optical Fiber Power Meters: A

Round Robin Test of Uncertainty,

R. L. Gallawa and Shao Yang,

Appl. Opt. 25, 1066 (Apr. 1986).

92

Chapter

Radioactivity Sources Q Neutron Sources and Neutron

Dosimetry

C Dosimetry of X Rays, Gamma Rays,

and Electrons O Dosimetry for High-Dose Applications
Ionizing Radiation Measurements

Radioactivity Sources

Technical Contacts:

Jacqueline M. Pamela A. Hodge Cassandra Beck Calhoun 43030C-^3050C Administrative

Tel: 301/975-5538 Tel: 301/975-5544 and Ugistics

Tel: 301/975-5531

Mailing Address: C114 Radiation Physics, National Insti- tute of Standards and Technology, Gaithersburg, MD

20899-0001

Test No. Items 43010C Gamma-Ray-Emitting Radionuclides in Solution (Half Lives Greater Than 15 Days)

43020C Gamma-Ray-Emitting Radionuclides in Solution (Half Lives Less Than 15 Days)

43030C Alpha-Particle-Emitting Solid Sources, NIST 2 ira proportional counter 43040C Alpha-Particle-Emitting Solid Sources, NIST 0.8 -rra defined-solid-angle counter 43050C Alpha-Particle-Emitting Solid Sources, using both

counting systems

43060S Special Tests of Beta-Particle-Emitting Solution Sources — Liquid Scintillation Counting

43070S Special Tests of Beta-Particle-Emitting Solution Sources, Other Techniques

43090S Special Tests of Alpha-Particle-Emitting Solid Sources

Radioactivity Sources — General

Information (43010C^3090S)

The National Institute of Standards

and Technology offers calibration ser- vices for over 50 radionuclides. Calibrations are provided that meet the

requirements of industry, research,

environmental monitoring, and the

life sciences. Radioactivity calibration

services are available for alpha-particle solid sources, beta-particle solutions, and gamma-ray solutions.

In order to offer such a broad

range of services, NIST must place

stringent limitations on the physical

and chemical form and activity range

of sources that can be accepted. To

ensure that these specifications are understood, it is essential that there

be good communication between the

technical user and the technical contact at NIST. When planning to have

a source calibrated, the user should

discuss the following points with the

NIST contact: A. Type of calibration: Often, more than one type of calibration is available for a given source. A cobalt- 60 source, for example, may be cali- brated in terms of total activity or gamma-ray-emission rate. (Inquiries

regarding the calibration of radioactive sources for exposure rate should

be directed to the Dosimetry Group.

See tests 47010C to 47040S.) The re- quired total uncertainty in the cali- bration should also be discussed.

B. General packaging and shipping requirements: Two general re- quirements apply to all sources submitted for calibration: (1) all shipments must conform to applicable

Nuclear Regulatory Commission

(NRC) and Department of Transportation (DOT) packaging and

transport; and (2) source descriptions,

including approximate activity, must

be provided in advance. The NIST

Health Physics Group must approve

the receipt of radioactive material,

and sources may be refused if the necessary information is not available. C. Reports of Calibration: A Report of Calibration is sent upon completion of a radioactivity calibration

service. If the user has particular re- quirements for documentation of the

calibration, these should be discussed

with the technical contact at NIST

before the services are performed.

D. Sample Preparation, Packaging, and Shipping: All samples submitted for calibration must be

chemically and physically stable. The

95
chemical form of solutions suggested

for beta-particle emitters and gammaray emitters are described later in this document. A special lot of borosili- cate-glass ampoules must be used for gamma-ray emitters. Empty ampoules

are provided for this purpose. The

volume of material in the ampoule

should be 5.0 ±0.2 mL.

Packaging for all sources must be

in compliance with DOT and NRC

regulations. Copies of regulations may

be obtained from Operations Division, Office of Hazardous Materials,

Department of Transportation, Washington, DC 20950. Postal regulations

prohibit the mailing of radioactive

materials that require a caution label under DOT regulations.

Alpha-particle solid sources must

be supplied in special source holders

designed so that the active area is not touched by any material. For sources

to be measured in the 2 ira counter

(calibration 43030C), the diameter of

the source must be less than 10 cm

and that of the active surface less than 9 cm. For the 0.8 ira counter

(calibration 43040C), the maximum

diameter is 1.6 cm.

All sources arriving at NIST are checked by the Health Physics Group

for radiation level and source integrity. Sources should be shipped to the attention of the technical contact

at NIST, addressed, for example, as

follows: National Institute of Standards

and Technology

Attn: Jacqueline M. Calhoun

Health Physics (Radioactivity

Group)

Quince Orchard and Clopper

Roads

Gaithersburg, MD 20899-0001

Gamma-Ray-Emitting Solution

Sources (43010C^3020C)

Tables 8 and 9 list 41 radionuclide so- lutions that may be calibrated in the

NIST "4it"7 ionization chamber. The

sources must be submitted flamesealed in the special ampoules pro- vided by NIST. The operation of this type of chamber is described in NCRP Report 58, A Handbook of

Table 8: Specifications for Calibration of Gamma-Ray

Emitting Solutions Which Are Submitted for Calibration

Radionuclides Having Half Lives Greater Than 15 Days

Suggested Chemical Form' Nominal "3a"

Uncer. Limits

of Ionization- Activity

Radio- Chamber Range"*' nuclide Calibration^"' (MBq) Carrier Solution (%)

1.6 0.4-40 NaCl 1 M HCl

0.8 0.4 - 40 ScCla 1 M HCl

1.0 2-60 CrCl3 0.5 M HCl

1.2 2-60 MnCb 1 MHCl

"Co 0.8 2-60 C0CI2 1 M HCl

1.4 0.4 - 40 FeCh 1 MHCl

0.8 0.4-40 C0CI3 1 M HCl

75c „ be 2.4 2 — oU T I 0 .... /~\ H2C>e03 1 M HNO3

"'St 2.0 2-60 SrCl2 1 M HCl

0.7 0.4-40 YCI3 1 MHCl

'"^Cd- 1.7 2-60 CdCl2 1.3 M Hcr

-""Ag 0.9 0.4-40 AgNOs 1 M HNO3

"^Sn- 3.0 2-60 SnCb or SnCU

4 MHCl

114mj^ 1.0 2-200 InCl2 3 MHCl

123n, 1.0 2-100 TcCl 2 MHCl

1.5 2-60 BaCl. 1 MHCl

'^^Cs 1.0 2-60 CsCl 1 MHCl

'3'Cs- 1.5 2-60 CsCI 1 MHCl

1.0 2-60 CeCb 1 MHCl

'^'Ce 2.0 2-60 CeCb 1 MHCl

i^Ce 1.3 2-740 CeCl3 1 M HCL*

1.6 0.4-40 EUCI3 1 MHCl

•"Gd 1.9 2-60 GdCl3 1 M HCl*

0.8 0.4-40 EuCb 4 MHCl

1.5 2-60 EUCI3 4 MHCl

2.5 2-60 YbCh 0.1 M HCl*

2.3 2-60 KAu(CN)4 lOgL-'KCN*

203Hg

lOgL-' Kcr

1.4 2-60 Hg(N03)2 0.1 M HNO3

The total estimated uncertainty will depend upon the activity level and chemical form. The source activity should be in the indicated range when it arrives

at NIST. The calibration scheduling must be coordinated with the NIST technical contact. This information is based in large part on the NIST Standard Refer- ence Materials for these radionuclides. For those radionuclides marked

with an asterisk, the carrier should be discussed with the NIST technical contact. «"The calibration for '"^Cd - '"^""Ag and "'Sn-"'"'In are in terms of gamma-ray-emission rate rather than activity.

Radioactivity Measurements Procedures, Section 4.4 "Ionization Chambers," and in NBS SP 250-10,

Radioactivity Calibrations with the

"4it" Gamma Ionization Chamber

and other Radioactivity Calibration

Capabilities (see references).

96
43010C-43090S

Table 9: Specifications for Calibration of Gamma-Ray

Solution Sources Radionuclides Having Half Lives Less Than 15 Days

Nominal "3a"

Uncer. Limits

Suggested Chemical Form^"'

of lonization- Activity

Radio- Chamber Range""*

nuclide Calibration*"' (MBq) Carrier Solution (%)

0.8 0.4-40 NaCl 1 MHCl

"'Ga L4 0.4-40 GaClj 2MHC1

''Mo- 1.6 2-60 Molybdate 4 M HNO3

1.5 2-60 No carrier added/Saline

pertechnetate

i"In 1.3 2-60 InClj 3 MHCl

123j 1.5 2-60 KI, NasSOj 0.01 M LiOH*

131j 1.3 2-60 KI, Na2S03 0.01 M LiOH*

i^"Ba- 3.4 0.4-40 Ba(N03)2, 1 MHCl

La(N03)3

1.0 2-600 Re Saline

'''^Hg 2.4 2-60 Hg(N03)2 0.1 M HNO3

1.3 2-60 KAu(CN)4 lOgL-'KCl,

10 gL-'KCN

201'j'J 1.9 2-60 T(N03)3 0.9 M HNO3

203pb 1.7 2-60 PbCU 0.5 M HCl

The total estimated uncertainty will depend upwn the activity level and chemical form.

f**' The source activity should be in the indicated range when it arrives at NIST. The calibration scheduling must be coordinated with the NIST

technical contact.

'^^ This information is based in large part on the NIST Standard Refer- ence Materials for these radionuclides. For those radionuclides marked

with an asterisk, the carrier should be discussed with the NIST technical

contact.

Alpha-Particle-Emitting Solid Sources

(43030C^3050C)

Alpha-particle sources may be cali- brated using the National Institute of

Standards and Technology 2 ira proportional counter, or the National Institute of Standards and Technology

0.8 ira defined-solid-angle counter. The former calibration is in terms of

alpha-particle-emission rate into 2 ira steradians, while the latter is in terms

of total activity. A more detailed

comparison of these counting systems

is given in NCRP Report 58 (Section

3.7) and in NBS SP 250-5, AlphaParticle Calibrations. Backscattering

corrections for a variety of source- mount materials are discussed in the

references given. The source thick- ness must be such that more than 99.5

percent of the emitted alpha particles

have an energy greater than 400 keV.

Further specifications for these cali- bration services are given in Table 10. Test 43050C includes calibration of

the same source using both counting

systems.

Large area sources of plutonium238 may also be measured providing

the source thickness is as above. The

activity range is 10^ to 10^ Bq utilizing

Large-Area Internal and External

Counters.

Table 10: Specifications for Calibrations Using the 2 -na Proportional Counter and the 0.8 Tra Defined Solid

Angle Counter

Caiibration 43030C

Calibration 43040C

Counting System

Sources Calibrated Fon

NIST 2 -ira proportional counterNIST 0.8 -rra defined-solid- angle-counter

Total activity (in Bq)Alpha-particle

emission

rate into 2 -n-a steradians either above 400 KeV or extrapolated to zero KeV (in s"')

Nominal Uncertainty (~3a) 1.5 percent 1.5 percent

Activity Range ~(0.4- 10>-' ~(40-10')s-'

Maximum Source 10 cm (9 cm 1.6 cm

Diameter active surface)

The total estimated uncertainty will depend upon the activity level and

source geometry.

97
43010C-43090S

Jacqueline Calhoun places a gamma-ray emitting

radionuclide sample into the NIST "Att" a ionization

chamber.

Special Tests of Beta-ParticleEmitting Solution Sources

(43060S and 43070S)

Beta-particle-emitting solutions that conform to the physical, chemical,

and activity specifications for measurement are assayed by liquid-scintil- lation counting. The specifications are shown in Table 11. Solutions should

be approximately 5 mL in volume and

flame-sealed in glass vials or ampoules. The suggested radioactivity

concentration range is 20 to 2000

kBq/g.

Table 11: Specifications for Special Tests of

Beta-Particle-Emitting Solution Sources

Suggested Chemical Composition^'''

Radionuclide Nominal

Uncertainty^''^ (%)

Carrier Solution

1.0 H2O H2O

14^ 1.5 NazCOa 0.001 M NaOH

32p(c) 1.0 H3PO4 0.0034 M H3PO4

33p 1.0 H3PO4 0.0034 M H3PO4

35g 1.0 Li2S04 0.1 M HCl

2.0 NaCl H2O

1.0 SrCb 1 MHCl

90Sr_90Y 1.0 SrCl2/YCl3 1 MHCl

1.0 YCI3 1 MHCl

1.0 PmClj 1 MHCl

2.0 T1(N03)3 1 M HNO3

The total estimated uncertainty will depend upon the activity level and chemical form. The chemical composition is critical for these calibrations and

should be discussed before sending the source. This calibration includes a half-life fit to determine the "P impurity.

No examination is made for betaparticle-emitting impurities, except in the case of phosphorus-32 where a

half-life fit is made. The sources will be examined for gamma-ray emitting

impurities.

Measurement of beta-particleemitting solutions by techniques other

than liquid-scintillation may be made

by special arrangement.

Special Alpha-Particle-Emitting Solid

Sources (43090S)

Special arrangements may be made

for measurements of solid alphaparticle-emitting sources with emission rates exceeding 1.1 x 10" Bq.

References — Radioactivity Sources

NBS Measurement Services: Radioactivity Calibrations with the "4-ir" Gamma Ionization Chamber and

Other Radioactivity Calibration Capabilities, J. M. Calhoun, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-10

(Oct. 1987).

98
43010C-43090S

NBS Measurement Services: AlphaParticle Calibrations, J. M. R. Hutchinson, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-5 (July

1987).

NCR? Report 58, A Handbook of

Radioactivity Measurements Procedures, Section 3.7— Alpha-Particle

Counting, W. B. Mann, Ed., Natl. Council Rad. Protect, and Meas.,

Washington, DC (1985).

Study of the Scattering Correction for Thick Uranium-Oxide and Other aParticle Sources, I: Theoretical, L.

L. Lucas and J. M. R. Hutchinson,

Int. J. Appl. Radiat. Isotopes, 27,

35 (1976).

Study of the Scattering Correction for Thick Uranium-Oxide and Other aParticle Sources, II: Experimental,

J. M. R. Hutchinson, L. L. Lucas,

and P. A. Mullen, Int. J. Appl.

Radiat. Isotopes, 27, 43 (1976).

Backscattering of Alpha Particles

from Thick Metal Backings as a Function of Atomic Weight,

J. M. R. Hutchinson, C. R. Naas,

D. H. Walker, and W. B. Mann,

Int. J. Appl. Radiat. Isotopes, 19,

517 (1968).

An Experimental Study of the

Backscattering of 5.3 MeV-Alpha

Particles from Platinum and Monel

Metal, D. H. Walker, Int. J. Appl.

Radiat. Isotopes, 16, 183 (1965).

99
44010C-44100S

Neutron Sources and Neutron Dosimetry

Technical Contacts:

E. Dale McGarry

44010C, 44020C, 44100S

Tel: 301/975-6205

Robert B. Schwartz 44060C, 44I00S

Tel: 301/975-6203

Edward W.

Boswell 44010C-44060C

Tel: 301/975-6207

Mailing Address: A135 Reactor, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 44010C

44020C

44060C

44070C

44080C

44090C

44100S

Radioactive Neutron Sources (10^ to 10** n/s) Radioactive Neutron Sources (lO** to 10'" n/s) Personnel Protection Instrumentation, Californium Source Bare and Moderated

Activation Detector Dosimetry, Thermal Neutrons

Activation Detector Dosimetry, Californium Fission Neutrons

Activation Detector Dosimetry, ^'U Cavity Fission Source

Special Tests of Neutron Sources and Dosimeters

Radioactive Neutron Sources

(44010C-44020C)

NIST provides calibration services for radioactive neutron sources with

emission rates from 5 x 10^ to 1 x 10'" neutrons/second. Emission rates are determined by the Manganous Sulfate

Bath Method to an accuracy of about

1.2 percent (one sigma) depending

upon the details of source encapsulation. Sources to be calibrated are compared in the bath to the emission

rate of NBS-1, the national standard

Ra-Be photoneutron source. The

emission rate of NBS-1 (1.2 x 10* n/s

in January 1990) has an assigned uncertainty of ±0.85 percent (one

sigma).

Personnel Protection Instrumentations (44060C)

Neutron personnel instruments, both

passive (e.g., dosimeters) and active

(e.g., remmeters) are calibrated on

the basis of a certified free-field doseequivalent or dose equivalent rate. Two ^^Cf source-driven neutron fields are available on a routine basis for

this purpose: bare source and heavywater moderated ^^Cf fission neutron

sources. Thermal and filtered neutron

beams are also available for special

requirements under Test No. 44100S.

For both bare and moderated ^^Cf

source exposures, maximum doseequivalent rates are about 2 rem/h.

The calibration uncertainty is in the

range of ±5 percent (la), including a ±4 percent component for the dose

equivalent conversion factor.

100
44010C-44100S

Activation Detector Dosimetry

(44070C-44090C)

Passive neutron detectors, generally

activation foils, can be irradiated to a

certified neutron fluence (or average

fluence rate) in a fission spectrum or

a Maxwellian thermal neutron field. Irradiation parameters are given in Table 12.

Table 12: Irradiation Parameters for Fission Spectra

and Maxwellian Thermal Neutron Fields

Neutron Field

Typical

Maximum

Fluence

(n/s)

Typical

Maximum

Fluence Rate

(n/cm^)

Accuracy

(la) (%)

^^Cf Fission Source 5 X 10'^ 2x10' < ±1.3<''>

^'^U Cavity Fission 5 X 10'= 4 x 10^" < ±2.3^"' Source Thermal Neutrons 1 X 10'^ 8x10' ±2.5

Beam('=) Isotropic > 1 X 10^*^ 2x10" ±2.5

''^ Threshold detectors only. Maximum size of detector disks: 12.7 mm

dia. X about 3 mm thick. Radial gradient of fluence: about 20 percent

center-to-edge. Uncertainty includes neutron scattering corrections. Maxwellian distribution corresponding to a temperature of about

40 °C.

Special Tests of Neutron Sources and

Dosimeters (44100S)

Other tests of dosimetry instrumentation may be undertaken by special ar- rangement with the Ionizing

Radiation Division. In particular for personnel protection instruments, a thermal beam can provide dose equivalent rates of up to approximately 1 rem/h across a 30-cm diameter circle,

and three monoenergetic filtered neutron beams may be used to investi- gate neutron response as a function

of energy. Energies and typical dose

equivalent rates for the filtered beams are 2 keV (8 mrem/h),

24 keV (15 mrem/h), and 144 keV

(120 mrem/h).

References — Radioactive Neutron

Sources

NBS Measurement Services: Neutron

Source Strength Calibrations at NBS by the Manganese Sulfate

Bath Method, E. D. McGarry and

E. W. Boswell, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-18

(Mar. 1988).

Neutron Source Calibrations at NBS

for Calibration Checks of Neutron

Radiation Instruments, V. Spiegel,

Jr., Proc. of Symp. on Meas. for the

Safe Use of Radiation, Natl. Bur.

Stand. (U.S.), Spec. Publ. 456, 87

(Nov. 1976).

Calibration of Thermal Neutron

Absorption in Cylindrical and

Spherical Neutron Sources, V.

Spiegel, Jr., and W. M. Murphey,

Metrologia, 7, 34 (Jan. 1971).

The Correction Factor for Fast Neutron Reactions on Sulphur and

Oxygen in the ManganousSulfate-Bath Calibration of Neutron Sources, W. M. Murphey,

Nucl. Instrum. Methods, 37, 13

(1965).

Absolute Calibration of the National

Bureau of Standards Photoneutron

Source: III. Absorption in a Heavy Water Solution of

Manganous Sulfate, R. H. Noyce,

E. R. Mosburg, Jr., S. B. Garfinkel,

and R. S. Caswell, J. Nucl. Eng.,

17, No. 7, 313 (1963).

Absolute Calibration of the National

Bureau of Standards Photoneutron

Standard: I., J. A. DeJuren, D. W.

Padgett, and L. F. Curtiss, J. Res.

Natl. Bur. Stand. (U.S.), 55, 63

(Aug. 1955).

References — Personnel Protection

Instrumentation

NBS Measurement Services: Neutron

Personnel Dosimetry, R. B. Schwartz, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-12 (July 1987).

Calibrations and Use of Filtered

Beams, R. B. Schwartz, Proc. Intl. Specialists Symp. on Neut. Stand,

and Applic, Gaithersburg, MD,

Natl. Bur. Stand. (U.S.), Spec.

Publ. 493, 250 (Oct. 1977).

101
The Design and Construction of a D20-Moderated ^^^Cf Source for Calibrating Neutron Personnel

Dosimeters Used at Nuclear Power

Reactors, R. B. Schwartz and

C. M. Eisenhauer, U.S. Nucl. Reg.

Com. Doc. NUREG/CR-1204 (Jan.

1980).

References— Activation Detector Dosimetry

NBS Measurement Services: Activation Foil Irradiations at NBS by

Californium Fission Sources, G. P. Lamaze and J. A. Grundl. Natl. Bur. Stand. (U.S.), Spec. Publ. 250-

13 (Mar. 1988).

NBS Measurement Services: Activation Foil Irradiations at NBS by

Reactor Cavity Sources. G. P. Lamaze and J. A. Grundl, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-

14 (Mar. 1988).

Derivation of Neutron Exposure

Parameters from Threshold Detector Measurements, J. A. Grundl,

Proc. Sbcth ASTM-Euratom Symp. on Reactor Dosimeter, Jackson,

WY (June 1987).

Compendium of Benchmark Neutron

Fields for Reactor Dosimetry, J. A.

Grundl and C. M. Eisenhauer,

Natl. Bur. Stand. (U.S.), NBSIR

85-3151 (Apr. 1985).

The U.S. ^^^U Fission Spectrum Stan- dard Neutron Field Revisited, E. D. McGarry, C. M. Eisenhauer,

D. M. Gilliam, J. A. Grundl, G. P. Lamaze, and A. Fabry, Proc. Fifth

ASTM-Euratom Symp. on Reactor

Dosimetry, Geesthacht, Germany

(Sept. 1984).

National Standards for Neutron Measurements, J. A. Grundl, Proc. of a Meeting on Traceability for Ionizing Radiation Measurements, Natl. Bur. Stand. (U.S.), NBS Spec.

Publ. 609 (Feb. 1982).

Utilization of Standard and Refer- ence Neutron Fields at NBS, C. M.

Eisenhauer, D. M. Gilliam, J. A.

Grundl, and V. Spiegel, Proc. Sec- ond ASTM-Euratom Symp. on Reactor Dosimetry, Palo Alto, CA

(Oct. 1977).

A Californium-252 Fission Spectrum

Irradiation Facility for Neutron Reaction Rate Measurements,

J. A. Grundl, V. Spiegel, C. M.

Eisenhauer, H. T. Heaton II, D. M.

Gilliam (NBS), and J. Bigelow

(ORNL), Nucl. Tech. 32, 315 (Mar.

1977).

102
46010C-48020S

C,

Dosimetry of X Rays, Gamma

Rays, and Electrons

Technical Contacts:

Christopher G.

Soares

Test 47030C47036C, 47040S, 48010M-48020S

Tel: 301/975-5589

Bert M. Coursey

All Tests

Tel: 301/975-5584

Paul G. Lamperti

Tests 46010C46050S

Tel: 301/975-5591

Debra Bensen 46010C

Tel: 301/975-5556

James T. Weaver, Jr. Tests 47010C, 47011C, 47040S

Tel: 301/975-5586

Mailing Address: C214 Radiation Physics, Center for Radiation Research, National Institute of Standards and

Technology, Gaithersburg, MD 20899-0001

Shipment of Instruments: National Institute of Standards

and Technology, 1-270 at Quince Orchard Road, C214

Radiation Physics, Gaithersburg, MD 20899-0001

For: 46010C-46050S; Attn: P. J. Lamperti

For: 48010M-48020S; Attn: C. G. Soares

Shipment of Sources: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, B131

Radiation Physics, Gaithersburg, MD 20899-0001

For: 47010C-47040S;

Attn: Health Physics/J. T. Weaver

(for Gamma-Ray Sources)

Attn: Health Physics/C. G. Soares

(for Beta-Particle Sources)

Test No. Items CO Special Instructions for Using Electron and Photon

Dosimetry Calibration and Test Services (46010C-48020S)

C.l X-Ray and Gamma-Ray Measuring Instruments 46010C Radiation Detectors — Calibration/Correction

Factor, One Beam Quality (See Tabic 13) 4601 IC Each Additional Beam Quality or Condition

46020C Passive Dosimeters — Irradiation of Up to Six, One

Beam Quality at One Set-Up

46021C Up to Six Additional Dosimeters at Same Sct-Up

and Beam Quality

46030S Special Tests of High-Gain Electrometers — Charge

Sensitivity, One Set of Switch Positions, with 46010C/46011C, by Prearrangemcnt

46040S Special Tests of X-Ray Penetramctcrs, ArdranCrookes Type

46050S Special Tests of X-Ray and Gamma-Ray Measuring

Instruments

C.l Gamma-Ray Sources, Beta-Partlcle Sources,

and Measuring Instruments 47010C Gamma-Ray Sources Similar to NIST Standards —

'^Co or '-"Cs Having Air-Kerma Strengths 10 to 1500 iiGy mVh, and '^^I or '^'Ir Sources: Same Type

Seeds Used to Calibrate Reentrant Chamber Having

Air-Kerma Strengths 0.1 to 30 p-Gy mVh

47011C Each Additional Gamma-Ray Source of Same

Radionuclide

47030C Beta-Particle Sources Calibrated for Surface Dose Rate 47035C Beta-Particle Sources Calibrated for Radiation

Protection 47036C Ionization Chambers Calibrated with Beta-Particle Sources for Radiation Protection 47040S Special Tests of Gamma-Ray and Beta-Particle Sources

C.3 Dosimetry of High-Energy Electron Beams

48010M Dose Interpretation of NIST-Packagcd

Ferrous-Ferric (Fricke) Dosimeters Irradiated by

Customer — Three Dosimeters (Two for Irradiation,

One Control) 4801 IM Each Additional Dosimeter

48020S Special Tests of Electron-Beam Dosimeters

CO Special Instructions for Using

Electron and Photon Dosimetry

Calibration and Test Services

(46010C-48020S)

The NIST dosimetry calibration and

test services for x rays, gamma rays, beta particles, and electrons are per- formed in NIST's laboratories at Gaithersburg, Maryland. Inquiries

103
should be addressed to the appropriate technical contacts listed at the beginning of this section. The inquirer

must provide the name and telephone

number of an individual who can an- swer technical questions that may

arise in any inquiry, order, or shipment.

Upon receipt of a purchase order, a report number is assigned. Calibrations are generally performed in the

sequence established by those numbers, except when greater efficiency can be achieved by combining similar

calibrations, or when work for a cali- bration laboratory is given a higher

priority. Arrangements for calibration

must be made in advance by letter or telephone, so that the instrument or source to be calibrated will not be

shipped to NIST until the time of its scheduled calibration approaches. In- quiry should be made as to scheduling and turn-around time.

Except for negligence by its personnel, NIST assumes no responsibility

for loss of or damage to the instru- ments or sources while in its possession. The risk should be covered by

insurance.

The report of calibration or test

will carry a DG number (e.g., DG

9876/89). Subsequent reference to that calibration or test should cite the

DG number.

C.l X-Ray and Gamma-Ray Measuring Instruments (46010C-46050S)

X-ray measuring instruments are cali- brated in terms of air kerma or exposure by a substitution method in an

x-ray beam at a point where the rate has been determined by means of a standard free-air ionization chamber.

In order to provide instrument cali- brations over a wide range of x-ray beam qualities, many combinations of

generating potential and filtration are

available. These are listed in Table 13

as lightly (L), moderately (M), and

heavily (H) filtered beams. Two beam

qualities that do not fit into these cat- egories are considered as special (S)

qualities. Cobalt-60 and cesium-137

gamma-ray beams are also

available. The beam qualities are

identified by beam codes given in the

first column. The calibration beam

qualities requested should be appropriate to the instrument submitted.

Gamma-ray measuring instruments

are calibrated in terms of air kerma,

exposure, or absorbed dose at points

in the collimated cobalt-60 and ce- sium-137 gamma-ray beams that have

been standardized by means of

graphite cavity chambers or a graphite calorimeter. Rates at the

time of calibration are computed

from the original beam standardization data and appropriate decay corrections. Ionization chambers

submitted for an air kerma or exposure calibration should have sufficient wall thickness to provide electron

equilibrium for the gamma-ray energy

selected. Ionization chambers submitted for an absorbed-dose calibration

must be suitable for calibration in a phantom.

An ionization chamber and elec- trometer combination, with the elec- trometer marked in terms of air kerma, exposure, or absorbed dose, is calibrated by providing a dimensionless correction factor for the elec- trometer scale. An ionization

chamber and electrometer combination marked in electrical units is cali- brated as follows: (1) the chamber is calibrated in terms of air kerma, ex- posure, or absorbed dose per unit

charge using an NIST electrometer;

(2) the customer's electrometer is checked for linearity and charge measurement accuracy; and (3) the combination of chamber and electrometer

is checked for consistency. An ionization chamber submitted without an

electrometer is calibrated in terms of

air kerma, exposure, or absorbed dose

per unit charge. Calibration can be

based on measurements for positive or negative polarizing potential, or on

the mean of measurements for both

potentials, as requested. The ratio of

ionization currents for full and half polarizing potentials and the corre- sponding ionization current will be

stated in the calibration certificate.

104
46010C-48020S

Table 13: X-Ray Beam-Quality Parameters

Added Filter Homogeneity I!^llcLll Vc Code Layer Coefficient Energy Min. Max.

Al Cu Sn Pb AI Cu Al Cu (keV) (ftGy/s) (mGy/s)

(mm) (mm) (mm) (mm (mm) (mm)

LIO 0. 0.029 ly 0.009 15 L15 0. 0.050 74 0.009 37 L20 0. 0.071 /D 0.009 29 L30 0.265 0.22 OU 0.009 4 L40 0.50 0.49 J / 0.009 4 L50 0.639 0.75 58 0.009 4 L80 1.284 1.83 58 0.009 4 LlOO 1.978 2.8 59 0.009 4 M20 0.230 0.152 ly 0.009 4.4 M30 0.50 0.36 54 0.009 3 M40 0.786 0.73 00 0.009 4 M50 1.021 1.02 0.032 00 oz 0.009 4 M60 1.51 1.68 0.052 ^000 04 7 2 MlOO 5.0 5.0 0.20 11 rcJJ 9 3 M150 5.0 0.25 10.2 0.67 o 1 OZ 9 4 M200 4.1 1.12 14.9 1.69 yj AO 9 3 M250 5.0 3.2 18.5 3.2 08yo CA50 9 2 M300 4.0 6.5 22. 5.3 100 97 4 0.7

HIO 0.105 0.048 ftO 0.009 0.03 HI S 0.500 0 1 S9 87 0 OOQ

H20 1.021 0.36 88 0.009 0.03 H30 4.13 1.23 0.038 01yj 04y'i 0.009 0.03 H4n otu 4.05 0.26 04y'i 0^yj u.yjj H50 4.0 0.10 4.2 0.142 92 90 38 3 0.6 H60 4.0 0.61 6.0 0.24 94 89 46 0.2 0.04 HlOO 4.0 5.2 13.5 1.14 100 94 80 0.04 0.02 H150 4.0 4.0 1.51 17.0 2.5 100 95 120 0.3 0.09 H200 4.0 0.60 4.16 0.77 19.8 4.1 100 99 166 0.2 0.05 H250 4.0 0.60 1.04 2.72 22 5.2 100 98 211 0.3 H300 4.1 3.0 5.0 23 6.2 99 98 252 0.4 0.03

S75 1.504 1.86 63 0.009 4 S60 4.0 2.8 0.089 75 70 3 0.5

'"Cs 10.8 662 13 0.9 '"Co 14.9 1250 13 22

For the x-ray beam codes, the letter indicates light, moderate, heavy, and special filtration and the number is the constant potential in kilovolts. The inherent filtration is approximately 1.0 mm Be for beam codes LIO-LIOO, M20-M50, H10-H40, and S75; and 3.0 mm Be for beam codes M60-M300, H50-H300, and S60. The half-value layers for '^^Cs and '^'Co are calculated. The homogeneity coefficient is taken as 100 x (1st HVL)/(2nd HVL).

The calibration distance is 25 cm for beam codes LIO, L15, HIO, and H15; 50 cm for beam codes L20-L100,

M20-M50, H20-H40, and S75; and variable for the remaining beam codes. To get exposure in R multiply air kerma in mGy . g -j^ in mR p-Gy

105
Ionization chambers are tested,

prior to calibration, for leakage, stabi- lization time, short-term stability, re- combination loss, and connection to the atmosphere. Chambers found unsuitable for calibration will be re- turned with a statement of the reason

for rejection. A charge may be made

for time incurred on the tests. Each instrument submitted to NIST

for dosimetry calibration or test must

be uniquely identified, usually by the

manufacturer's name, model number,

and instrument serial number. When

the serial number is lacking, an alter- native identifying mark should be

provided. If none is found, NIST will mark the piece with an identification

number. If the apparatus submitted

has been calibrated previousl> by

NIST, the serial number or identifying mark should be given on the new

order so that a continuing record of

stability can be maintained.

All shipments to NIST of instru- ments for dosimetry calibration must

be in reusable containers. Even if properly packed, there can be no as- surance that a calibrated instrument

has maintained its calibration during

shipment unless a method of verifying

instrument stability has been established. Measurement should be made

of the instrument response both before and after shipment, using a longlived radioactive source and a highly

reproducible measurement procedure.

A long-term record of instrument stability using a suitable constancy check

procedure is the most effective method for assuring the validity of

the instrument calibration. Irradiation of passive dosimeters,

for readout by the customer, is avail- able for most of the beam qualities

listed in Table 13. These irradiations are generally in terms of air kerma or exposure; for passive dosimeters suit- able for insertion in a phantom, irra- diation in terms of absorbed dose can be provided by in-phantom irradiation

using cobalt-60 gamma rays.

X-ray penetrameters, of the

Ardran-Crookes type, can be cali- brated using constant x-ray generating

potentials up to 300 kV. These penetrameters are used for measurement

of the generating potential of diagnostic x-ray units.

Debbie Benson sets up an ionization chamber for cali- bration. The calibrated chambers are used as stan- dards for radiation exposure by medical industrial and

research organizations.

106
46010C-48020S

C.2 Gamma-Ray Sources, BetaParticle Sources, and Measuring

Instruments (47010C-47040S)

Sources submitted to NIST for dosimetry calibration are subject to the following conditions:

A. Preparation: Sources submitted for calibration must be sealed so

that there can be no escape of any ra- dioactive material, including any

gaseous decay products. The sources,

shielding, and packaging must be free of contamination. Contaminated or

leaking sources cannot be measured

and may cause considerable loss of

time and damage to laboratory facilities. Sources must have been sealed

for a sufficient time to be substantially in radioactive equilibrium with

their decay products when these contribute to the emitted radiation. B. Packaging for shipment: Packages must be in compliance with the

regulations of the Department of

Transportation as specified in DOT

49CFR173.401-173.478. Radionuclides

must be packaged as Limited Quantities (DOT 49CFR173.421) or in Type

A packages (DOT 49CFR173.4 12 and

173.433). Type A packages must bear

the appropriate radioactive-hazard la- bels (DOT 49CFR172.403). If the source is considered by the shipper to be in DOT Special Form, a Special

Form certificate must be furnished to NIST in strict compliance with DOT

49CFR173.476. Copies of the codes

are available from the Government

Printing Office, Washington, DC

20402.

All shipments to NIST of gammaray and beta-particle sources should

be in reusable containers. A drawing

showing the source container and a description of the method of source removal should be provided before

the shipment is received at NIST.

Postal regulations preclude shipment of dosimetry sources via the

Postal Service.

If the nature of the shipment re- quires a Type B container subject to an NRC quality assurance program,

documentation should be supplied to NIST certifying that the use of the

container by NIST is part of the pro- gram of the shipper.

C. Possession of licensed materials: In submitting a source for cali- bration, it is necessary for the

submitter to certify that he is duly authorized to possess the source under

license by the applicable authority. In the case of individuals residing in a State that has entered into agreement

with the Nuclear Regulatory Commission, State regulations are applicable

to all sources. In the case of other in- dividuals, NRC regulations are applicable. This certification may be by

letter, by a suitable statement on the

purchase order covering the calibration fee, or by a clear copy of the

submitter's Possession License for the

source. Calibration in terms of air kerma

strength (air kerma rate in free space

times the square of the distance of

the calibration point from the source

center along the perpendicular bisector) is provided for gamma-ray

sources of cobalt-60, cesium-137,

iridium-192, and iodine-125.

Calibration in terms of absorbeddose rate is provided for suitable

encapsulated beta-particle sources; the dose rate to a low-atomic-number

material (graphite or plastic) is determined by measurement with an

extrapolation chamber. The betaparticle sources may be either small- area sources such as ophthalmic applicators, or large-area plaques, and

will be calibrated for absorbed dose

rate to water either at the source sur- face or at a specified distance.

Ionization chambers to be cali- brated with beta-particle sources must

be parallel-plate chambers with thin

walls. They can be calibrated with the

radionuclides '"Sr + "^Y, or '""^1, or

'^'Pm.

107
C.3 Dosimetrj' of High-Energy

Electron Beams (48010M-48020S)

Dosimeters are provided twice a year

to users requesting assistance with

absorbed-dose measurements in highenergy electron beams. The dosimeters consist of ferrous sulfate (Fricke)

solution in radiation-resistant silica- glass spectrophotometer cells. The

user irradiates all but one of the

three furnished dosimeters to between 50 and 80 Gy (5000 and 8000

rad) to water at electron energies between 5 and 50 MeV, employing the

irradiation geometry (field size, phantom, position of dosimeter in phantom) given in the "Protocol for Dosimetry of High-Energy Electrons," Physics in Medicine and Biology 11, 505 (1966).

After irradiation, the dosimeters

are returned to NIST for spectrophotometric evaluation of the ferric-ion concentration in terms of absorbed

dose in the phantom, using the eG

product given in "Radiation Dosimetry: Electron Beams with Energies between 1 and 50 HeV," ICRU Report

35 (1984).

References — Dosimetry of X Rays,

Gamma Rays, and Electrons

C.l X-Ray and Gamma-Ray

Measuring Instruments NBS Measurement Services: Calibration of X-Ray and Gamma-Ray

Measuring Instruments, P. J. Lamperti, T. P. Loftus, and R.

Loevinger, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-16 (Mar. 1988).

The Photon-Fluence Scaling Theorem

for Compton-Scattered Radiation,

J. S. Pruitt and R. Loevinger, Med.

Phys., 9, 176 (1982).

The Graphite Calorimeter as a Stan- dard of Absorbed Dose for Cobalt60 Gamma Radiation, J. S. Pruitt,

S. R. Domen, and R. Loevinger, J. Res. Natl. Bur. Stand. (U.S.), 86,

495 (1981).

j Uncertainty in the Delivery of Absorbed Dose, R. Loevinger and

T. P. Loftus, Ionizing Radiation

Metrology, International Course at Varenna, Italy, 1974, E. Casnati,

Ed., G-6, 459, Editrice Compositori, Bologna (1977).

Medical Dosimetry Standards Pro- gram of the National Bureau of

Standards, R. Loevinger, Proc. Symp. on Natl, and Intl. Standardization in Rad. Dosimetry, Atlanta,

GA, Dec. 5-9, 1977, Intl. Atomic

Energy Agency, Vienna (1978).

(This article provides references for

earlier publications on NBS exposure and absorbed-dose standards.)

Exposure Spectra from the NBS Vertical-Beam ^Co Gamma-Ray

Source, M. Ehrlich and C. G.

Soares, Natl. Bur. Stand. (U.S.),

NBSIR 76-1117 (1976).

Spectrometry of a '^'Co Gamma-Ray

Beam Used for Instrument Calibration, M. Ehrlich, S. M. Seltzer, M.

J. Bielefeld, and J. I. Trombka,

Metrologia, 12, 169 (1976).

C.l Gamma-Ray Sources, Beta-Particle

Sources, and Measuring Instruments NBS Measurement Services: Calibration of Gamma-Ray-Emitting

Brachytherapy Sources, J. T. Weaver, T. P. Loftus, and R.

Loevinger, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-19 (1988).

NBS Measurement Services: Calibration of Beta-Particle Radiation In- strumentation and Sources, J. S. Pruitt, C. G. Soares, and M.

Ehrlich, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-21 (Apr. 1988).

NBS Measurement Services: Calibration of Beta-Particle-Emitting Ophthalmic Applicators, J. S. Pruitt, Natl. Bur. Stand. (U.S.), Spec.

Publ. 250-9 (July 1987).

Calibration of Beta-Particle Ophthalmic Applicators at the National

Bureau of Standards, J. S. Pruitt,

J. Res. Natl. Bur. Stand. (U.S.), 91,

165 (1986).

108
46010C-48020S

The Effect of Altitude on Beta-Ray

Source Calibrations, J. S. Pruitt,

Rad. Protec. Dosim. 11, 151 (1984).

Exposure Standardization of lodine125 Seeds Used for Brachytherapy,

T. P. Loftus, J. Res. Natl. Bur.

Stand. (U.S.), 89, 295 (1984).

Standardization of Iridium-192

Gamma-Ray Sources in Terms of

Exposure, T. P. Loftus, J. Res.

Natl. Bur. Stand. (U.S.), 85, 19

(1980).

Medical Dosimetry Standards Pro- gram of the National Bureau of

Standards, R. Loevinger, Proc. Symp. on Natl, and Intl. Standardization in Rad. Dosimetry, Atlanta,

GA, Dec. 5-9, 1977, Intl. Atomic

Energy Agency, Vienna (1978).

(This article provides references for

earlier publications on NBS exposure and absorbed-dose standards.)

Standardization of Cesium-137

Gamma-Ray Sources in Terms of

Exposure Units (Roentgens), T. P. Loftus, J. Res. Natl. Bur. Stand.

(U.S.), 74A, 1 (1970).

C.3 Dosimetry of High-Energy

Electron Beams

NBS Measurement Services: Fricke

Dosimetry in High-Energy Electron

Beams, C. G. Soares, E. L. Bright,

and M. Ehrlich, Natl. Bur. Stand.

(U.S.), Spec. Publ. 250-4 (1987).

Uniformity of High-Energy ElectronBeam Calibrations, M. Ehrlich and

P. J. Lamperti, Phys. Med. Biol. 14, 305 (1969).

Proposed National Bureau of Stan- dards Program for the Calibration

of Instruments Used in HighEnergy Electron and X-Ray Beams,

M. Ehrlich, Ann. N.Y. Acad. Sci. 161, 139 (1969).

109
49010C-49050S

Dosimetry for High-Dose Applications

Technical Contacts:

Jimmy C. William L. James M.

Humplireys McLaughlin Pulil Tel: 301/975-5582 Tel: 301/975-5559 Tel: 301/975-5581

Mailing Address: C214 Radiation Physics, National Insti- tute of Standards and Technology, Gaithersburg, MD

20899-0001

Test No. Items 49010C Calibration Irradiations of Customer-Supplied

Dosimeters with '^Co Gamma Rays

49020C Dose Interpretation of NIST Transfer Dosimeters

Irradiated by Customer

49030C Dose Interpretation of Each NIST Transfer Dosimeter in Addition to Those Supplied

under 49020C

49040S Special Tests of Dosimeters by Reading with

Spectrophotometer, Optical Density at One to Five Wavelengths (Each Dosimeter)

49041S Spectrophotometric Readings of Dosimeters,

Ultra-Violet and Visible Spectrum Scan (Each Dosimeter)

49050S Special Measurement Services for Dosimeter

Response and Dose Distributions

Calibration Services and Special Tests of Dosimeters (49010C-49050S)

The following dosimetry services are

for individual users of intense radiation fields, in particular large

gamma-ray sources and electron ac- celerators up to approximately 10

MeV. These services include the administering of known absorbed doses

of photons to customer-supplied

dosimeters; supplying calibrated

transfer standard dosimeters to cus- tomers for irradiation and subsequent

readout and dose interpretation; and

special measurement services such as

the determination of temperature dependence, dose-rate dependency or

reproducibility of dosimeter response.

Calibration of Dosimeters Irradiated

with *"Co Gamma Rays (49010C)

Calibration irradiations are available

for customer-supplied dosimeters

(such as solid radiochromic or liquid

chemical types) or test samples that are sent to NIST, where they are packaged appropriately to provide

electron equilibrium conditions. They

are irradiated in the NIST standard

cobalt-60 calibration facility to

specific agreed-upon absorbed dose

values in the nominal "high-dose"

range of 10-10* grays (10^-10* rads).

The dosimeters are then sent back to the customer for analysis and evaluation. Dosimeters should not exceed

dimensions of 1 cm x 2 cm x 5 cm. A detailed list of the various sources

of uncertainty and estimates of the

magnitude of those uncertainties that make up the overall uncertainty for these services may be obtained by re- questing such information from NIST.

The uncertainties are divided into

two types: random and non-random.

Typical values for these uncertainties

for irradiations with the standard water-shielded source are: Random Uncertainties: The total random uncertainty associated with

these irradiations has been determined by statistical methods to be

±0.7 percent at a 95 percent confidence level. Non-random Uncertainties: These

are estimates that include all uncertainties not derived by the statistical methods above. The total estimated

non-random uncertainty is ±2.1 per- cent at a 95 percent confidence level. Overall Uncertainty: The random

and non-random uncertainties have

been combined in quadrature (that is, the square root of the sum of the

squares) to yield an overall uncertainty of ±2.2 percent at a 95 percent

confidence level.

110
49010C-49050S

Transfer Reference Standard

Dosimeters (49020C and 49030C)

NIST provides transfer standards in the form of sets of calibrated ra- diochromic dosimeters packaged in appropriate equilibrium materials

such as polystyrene or aluminum. The

sealed, packaged dosimeters are sent

to the customer for irradiation to nominal agreed-upon absorbed dose

levels in a prescribed geometrical ar- rangement. The unopened packaged

dosimeters are then returned to NIST

to be read and evaluated and the re- sults reported, thus providing calibra- tion of the customer irradiator. The

absorbed dose range that is suitable

for use with the transfer dosimeters is 1 to 50 kGy (0.1 to 5 Mrad) in water,

silicon, aluminum, graphite, or certain

plastics. The absorbed dose rate should be greater than 30 Gy/min.

Special Tests of Dosimeters:

Spectrophotometric Reading

(49040S-49041S)

Dosimeters may be read at several

specific ultraviolet or visible optical

wavelengths or as a spectral scan over an appropriate wavelength region of

interest.

Special Measurement Services for Dosimeter Response and Dose

Distributions (49050S)

Tests of dosimeter response, such as temperature dependence, dose rate dependence, and dose distributions in specific irradiation geometries, can be

provided as special measurement services. These dose distribution measurements can include dose profiles

in heterogenous absorbers and at in- terfaces of different materials.

References — High-Dose Dosimetry

NBS Measurement Services: Dosimetry for High-Dose Applications,

J. C. Humphreys, D. Hocken, and

W. L. McLaughlin, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-11

(Mar. 1988).

Dosimetry for Industrial Radiation

Processing, W. L. McLaughlin,

J. C. Humphreys, and A. Miller, Natl. Bur. Stand. (U.S.), Spec.

Publ. 609 (1982).

A National Standardization Pro- gramme for High-Dose Measurements, W. L. McLaughlin,

Technical Report No. 205, 17, Intl. Atomic Energy Agency, Vienna

(1981).

Dye Film Dosimetry for Radiation

Processing, J. C. Humphreys and

W. L. McLaughlin, IEEE Trans.

Nucl. Sci., NS-28, 2, 1797 (Apr.

1981).

The Measurement of Absorbed Dose

and Dose Gradients, W. L. McLaughlin, Radiat. Phy. Chem.,

15, 9 (1980).

Dosimetry Standards for Industrial

Radiation Processing, W. L. McLaughlin, National and International Standardization of Radiation

Dosimetry, 1, Intl. Atomic Energy

Agency, Vienna (1978).

Ill
Chapter

A l}fkciGf*3n/^f> lV4fpfiGiit*PiTi^fif'<c iVCSlai-dllVv iVtCuaUl vlllvlll-d B Impedance Measurements

C Voltage Measurements

D Precision Ratio Measurements

E Phase Measurements and

Air Navigation Aids

F Power and Energy Measurements,

Low-Frequency

G Microwave Measurements

H Noise Temperature Measurements

1 Electromagnetic Field Strength and

Antenna Measurements

J Pulse Waveform Measurements
Electromagnetic Measurements 51100S-51163C

Resistance Measurements

A.1 DC Resistance Standards and

Measurements

Technical Contacts:

Ronald F. Dziuba

Tel: 301/975-4239

Norman B. Belecki

Tel: 301/975-4223

Denise D. Prather

Administrative and Logistics

Tel: 301/975-4221

Mailing Address: B146 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items Test No. Items 51100S Special Resistance Measurement Services, by

Prearrangement

51110M Measurement Assurance Program Services for Resistance

51130C Standard Resistor, Thomas-Type, 1 fl 51131C Standard Resistor, Evanohm Wirewound High

Precision, 10 kfi 51132C Standard Resistor, Four-Terminal, 0.0001 fl 51133C Standard Resistor, Four-Terminal, 0.001 H

51134C Standard Resistor, Four-Terminal, 0.01 fi 51135C Standard Resistor, Four-Terminal, 0.1 H

51136C Standard Resistor, Four-Terminal, 1 ft 51137C Standard Resistor, Four-Terminal, 10 fi 51138C Standard Resistor, Four-Terminal, 100 fi 51139C Standard Resistor, 1 kfi 51140C Standard Resistor, 10 kfi 51141C Standard Resistor, 100 kfi 51142C Standard Resistor, 1 Mfi

51143C Standard Resistor, 10 Mfi

51144C Additional Voltage

51145C Standard Resistor, 100 Mfi

51146C Additional Voltage

51147C Standard Resistor, 1 Gfi

51148C Additional Voltage

51149C Standard Resistor, 10 Gfi

51150C Additional Voltage

51151C Standard Resistor, 100 Gfi

51152C Additional Voltage

51153C Standard Resistor, 1 Tfi

51154C Additional Voltage

51160C Standard Resistor for Current Measurements

(Shunts), One Range, One Current Not to Exceed

300 A

51161C Standard Resistor for Current Measurements

(Shunts), One Range, One Current between 300 A

and 1000 A

51162C Standard Resistor for Current Measurements

(Shunts), Additional Range of a Muhi-Range

Resistor 51163C Standard Resistor for Current Measurements

(Shunts), Additional Determination at Another

Current Level

113
Special DC Resistance Measurements, by Prearrangement (51100S)

Testing or evaluation of prototype re- sistance standards or measuring in- struments; unique resistance

measurements; and other calibration

services not specified below, such as the determination of the pressure coefficient of Thomas-type resistors, the

determination of the temperature coefficient of standard resistors, and the

calibration of resistance standards in

oil at temperatures other than 25 °C, are carried out under this test number. Such measurements are made at the discretion of the NIST technical

staff in a manner specifically agreed

upon by the customer and the expert

involved. Testing of component resis- tors will only be considere J under the

rare circumstance that the behavior

of the resistors has been observed to approximate that of state-of-the-art standards under the same conditions.

Measurement Assurance Program

Services for Resistance (51110M)

Resistance MAP transfers are generally carried out at the 1-ohm and

10-kilohm levels. Four well-characterized commercial standard resistors are used as transport standards at each level. The suggested measure- ment schedule at the client laboratory

consists of measurements on each

transport resistor three times a week

for a period of 4 to 6 weeks, depending upon the settling time of the re- sistors due to transportation effects. Participation in this program is generally not advisable unless one is required to support resistance measurements at or near state-of-the-art accuracies and is willing to adopt a system for the continuous surveillance

of standards during the intervals between NIST MAP transfers. A successful transfer requires a considerable amount of data collection

and a willingness to become involved

in the data analysis process. Data

supplied in the course of routine

NIST calibrations suffice for normal

measurement requirements of stan- dards laboratories if proper methods

are used by the laboratory to quantify

the additional uncertainties caused by

transportation and the laboratory's own measurement process.

Special Standard Resistors 1 il and

10 kn (51130C and 51131C)

Thomas-type 1 ohm resistors or their equivalent are calibrated directly

against the NIST 1 ohm reference

group that is used to maintain the U.S. legal ohm. Special 10-kilohm

standard resistors designed for air or

011 use are calibrated directly against

the NIST 10-kilohm working stan- dards. The special 10-kilohm standard

resistors (Evanohm wirewound highprecision or equivalent) are characterized by resistance corrections

within 10 ppm of nominal value, temperature coefficients of 0± 1 ppm/°C

at the operating temperature, and

drift rates of ^ 1 ppm/year.

The customer resistors are acclimatized in their respective test environments for approximately 1 week prior

to their calibration. Measurement

parameters of temperature and current level are as follows:

Resistor Medium Temperature Current

(°C) in oil 25.00 ±0.003 100mA

10 kn oil 25.00 ±0.01 1mA

10 kn air 23.0 ±1.0 1 mA

The temperature of the customer resistor at the time of the measurement

is given in the report of calibration. Since the Thomas-type resistor exhibits a significant pressure coefficient, the barometric pressure at the

time of the measurement is also re- ported. Uncertainties are based upon

(1) the random behavior of the measurement process as characterized by

data from a large population of indi- vidual calibrations, and (2) an esti- mate of the systematic errors arising

from such sources as temperature in- accuracies, pressure inaccuracies,

scaling errors, etc. Uncertainties are

listed in Table 14 on the next page.

Standard Resistors 10"-10* SI (51132C-51142C)

Standard resistors with nominal

decade values in the range between

114
51100S-51163C

10"'' and 10* ohm are calibrated by

comparison with NIST working stan- dards of equivalent value. In general,

these standards are characterized by

(1) resistance corrections within 500

ppm of nominal value, (2) temperature coefficients of ^ 10 ppm/°C at the temperature of use, and (3) drift rates of ^ 5 ppm/year. Normally,

standard resistors are measured in an

oil bath maintained at 25.0 ±0.05 °C,

and at a power level of ^0.1 W. Resistors in temperature-controlled enclosures with fixed terminations are

also accepted for calibration. At the

levels of accuracy involved, four- terminal measurements are required

for resistors whose nominal values are 100 ohms or less. Uncertainties are based upon (1) the random behavior

of the measurement process as characterized by data from a large population of individual calibrations, and

(2) an estimate of the systematic

errors. Uncertainties are given in Table 14.

Table 14: Calibration Uncertainties for DC Resistance Standards

Test Number

Nominal

Resistance

(ohms)

Terminal

Connection

Maximum

Power

(mw)

Uncertainty

(ppm)

51130C 1 (Thomas) 4 10 0.08 51131C 10'* (Special) 5 10 2 51132C 10-" 4 100 17 51133C 10-^ 4 100 7 51134C 10-2 4 100 4 51135C 10-' 4 100 3 51136C 1 4 50 2 51137C 10 4 50 2 51138C 102 2 10 1 51139C 10^ 2 10 1 51140C 10" 2 10 1 51141C 10^ 2 10 3 51142C 10* 2 10 5 51143C 10' 3

* 20-1000

51145C 10» 3

* 50-1000

51147C 10" 3

* 20-1000

51149C 10'" 3

* 1000 51151C 10" 3

* 1000 51153C 10'2 3

* 2000

* Resistors at this level are tested at customer-specified voltages up to 1 kV.

High-Valued Standard Resistors:

10'-10'2 n (51143C-51154C)

High-value standard resistors in the

range between 10' and lO'^ ohms are

calibrated in an air bath maintained

at a temperature of 23.0 ±0.5 °C and

at a relative humidity of 35 ±5

percent. Customer resistors are compared 1:1 with NIST working stan- dards of the same nominal value up

to and including the 10'" ohms level. Above 10'" ohms, 10:1 and 100:1 ratio techniques are employed. The maximum test voltage is 500 volts for resistors < 10'" ohms and 1000 volts for

resistors > 10'" ohms. Uncertainties

depend upon the stability and per- formance of the specific resistor involved and are given in Table 14. Only resistors that are mounted in a shielded enclosure with a permanent

identifying number and have suitable

terminations are accepted for cal- ibration. The resistance of thin-film, highvalued resistance standards is fre- quently highly voltage dependent.

Hence, the magnitude of the test voltage should be specified by the

customer when a resistor is submitted

for calibration. The temperature, rel- ative humidity, and test voltage of the

resistor are given in the report of cal- ibration.

High-Current Standard Resistors —

Shunts (51160C-51163C)

Four-terminal standard resistors for use in the precise measurement of

high direct currents (shunts) are cali- brated by NIST only during May and

November of the calendar year. Ar- rangements should be made with

NIST prior to submitting a resistor for calibration. Normally only resis- tors of 0.04 percent accuracy or better

are calibrated. The maximum test current available is 1000 amperes.

The uncertainty of measurement depends largely upon the performance

of the customer resistor involved.

115
51100S-51163C

QUANTUM HALL EFFECT

The U.S. National Ohm, on which NIST services for d-c

resistance are directly based, is now implemented in the

form of a quantum Hall effect system.

References — DC Resistance

Guidelines for Implementing the New

Representation of the Volt and

Ohm Effective January 1, 1990,

N. B. Belecki, R. F. Dziuba, B. F. Field, and B. N. Taylor, Natl. Inst. Stand. Technol. Tech. Note 1263

(June 1989).

New Realization of the Ohm and

Farad Using the NBS Calculable

Capacitor, J. Q. Shields, R. F. Dziuba, and H. P. Layer, Conf.

Precision Electromagnetic Meas.

(CPEM '88), June 7-10,1988,

Tsukuba Science City, Japan,

Special Issue CPEM '88 IEEE

Trans. Instrum. Meas., Vol. 38, No.

2, 249-251 (April 1989).

Determination of the Time-Dependence of Ones Using the Quantized

Hall Resistance, M. E. Cage, R. F. Dziuba, C. T. Van Degrift, and D.

Yu Conf. Precision Electromagnetic

Meas. (CPEM '88), June 7-10, 1988,

Tsukuba Science City, Japan, Special Issue CPEM '88 IEEE Trans.

Instrum. Meas., Vol. 38, No. 2, 263-

269 (April 1989).

Monitoring the U.S. Legal Unit of

Resistance via the Quantum Hall

Effect, M. E. Cage, R. F. Dziuba,

B. F. Field, T. E. Kiess, and C. T. Van Degrift, IEEE Trans. Instrum. Meas., IM-36, 222 (June 1987).

The NBS Ohm Past-Present-Future, R. F. Dziuba, Proc. Meas. Science

Conf., Irvine, CA (Jan. 1987).

A Test of the Quantum Hall Effect as

a Resistance Standard, M. E. Cage,

R. F. Dziuba, and B. F. Field,

IEEE Trans. Instrum. Meas., IM34, 301 (1985).

Automated NBS 1-Ohm Measurement System, K. R. Baker and

R. F. Dziuba, IEEE Trans. In- strum. Meas., IM-32, 154 (1982).

An Integrated System for the Precision Calibration of Four-Terminal

Standard Resistors, T. E. Wells and

E. F. Card, IEEE Trans. Instrum. Meas., IM-20, 253 (Nov. 1971).

Calibration Procedures for Direct

Current Apparatus, P. Brooks,

Natl. Bur. Stand. (U.S.), Monogr.

39 (Mar. 1962).

Measurement of Multimegohm Resistors, A. H. Scott, J. Res. Natl. Bur.

Stand. (U.S.), 50, No. 3 (Mar.

1953).

Precision Resistors and Their Measurement, J. L. Thomas, Natl. Bur.

Stand. (U.S.), Circular 470 (Oct.

1948).

Methods, Apparatus, and Procedures

for the Comparison of Precision

Standard Resistors, F. Wenner,

J. Res. Natl. Bur. Stand. (U.S.), 25, Res. Paper RP1323 (Aug. 1940).

116
Resistance Measurements

A.2 High-Voltage Standard Resistors

References — High-Voltage Standard

Resistors

Technical Contacts:

High-Voltage Divider and Resistor

Calibrations, M. Misakian, Natl. Bur. Stand. (U.S.), Tech. Note

1215 (July 1985).

Special Shielded Resistor for HighVoltage Measurements, J. H. Park,

J. Res. Natl. Bur. Stand., 66C,

No. 1, 1924 (Jan.-Mar. 1962).

Martin Misakian

Tel: 301/975-2426 William E. Anderson

Tel: 301/975-2423

Mailing Address: B344 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

[Attn: M. Misakian, Bldg. 220, Room B351]

Test No. Items 51210C High-Voltage Standard Resistors

High-Voltage Standard Resistors

(51210C)

A routine calibration service is maintained for resistors designed for dc

high-voltage applications. This service

is for nearly corona-free resistors designed for dc operation between 10

kV and 150 kV.

Resistors can be hand-carried or shipped to NIST. If they are shipped,

they should be packaged in sturdy

reusable containers. The design of

many high-voltage resistors makes

them vulnerable to shear-type forces, so provisions should be made to minimize the likelihood of damage due to such forces when the device is in the

shipping container.

II 117
51310S

A Resistance Measurements

A.3 High-Frequency Standard Resistors

Technical Contacts:

George M. Free Kathy Hillen

Tel: 303/497-3609 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

References — High-Frequency Standard Resistors

The Measurement of Lumped

Parameter Impedance: A Metrology Guide, R. N. Jones, Natl. Bur.

Stand. (U.S.), Monogr. 141 (June

1974).

Impedance of Lumped Circuits, L. E. Huntley and R. N. Jones, Proc. IEEE, 55(6), 900 (June 1967).

Test No. Items 51310S High-Frequency Standard Resistors; Two-Terminal

High-Frequency Standard Resistors

(51310S)

The overall frequency range covered

is 10 kHz to 250 MHz. The range of

resistance that can be calibrated depends upon the measurement fre- quency, as follows: Frequency Range

10 kHz-2 MHz

2 MHz-10 MHz

10 MHz-100 MHz

100 MHz-250 MHz

Resistance Range

o.in to 10 kn

50 n to 10 kn

20 n to 10 kn

20 n to 10 kn

Measurement uncertainties are given

in the reference; the minimum uncertainty provided is ±0.1 percent.

Reports of Calibration or Tests for

resistors will include the inductance

or capacitance associated with the resistor. Equivalent series values are normally given for inductive resistors and equivalent parallel values for ca- pacitive resistors.

118
Resistance Measurements « A.4 AC Resistors An Audio Frequency Four-Terminal

Resistance Bridge, T. M. Souders,

IEEE Trans. Instrum. Meas., IM23, No. 4, 342 (Dec. 1974).

References — AC Resistors

Technical Contacts:

T. Michael

Souders

Tel: 301/975-2406

Barry A. Bell

Tel: 301/975-2419

Mailing Address: B162 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 51410S Special Tests of AC Resistors, by Prearrangement

Special Tests of AC Resistors

(51410S)

Properly designed four-terminal ac

resistors in the range of 0.1 ohm to 0.001 ohm can be measured at cur- rent ratings not to exceed 50A. The

values for the ac resistance and phase

angle (or time constant) can be re- ported for frequencies between 50 Hz

and 10 kHz. To be accepted for test, resistors must have phase angles no

greater than 0.01 radian at all re- quested test frequencies.

This service is offered as a specialtest service; fees will be based on ac- tual costs. Prior arrangements are

essential.

119
52110S-52181C

B Impedance Measurements (Except Resistors)

B.1 Low-Frequency Capacitance and

Inductance Measurements and

Standards

Technical Contacts:

Y. May Chang Norman B. Denise D.

Tel: 301/975-4237 Belecki Prather

Tel: 301/975-4223 Administrative and Logistics

Tt:: 301/975-4221

Mailing Address: B146 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 52110S Special LF Impedance Measurements, by

Prearrangement

52130C Standard Fixed, Fused-Silica Dielectric Capacitor

(10 and 100 pF at 100, 400, or 1000 Hz)

52131C Additional Frequency Points 52140C Fixed Three-Terminal, High-Precision Standard

Capacitor with Coaxial Connectors (1 frequency

high accuracy under controlled conditions, 100, 400, or 1000 Hz)

52141C Additional Frequency Points 52150C Physical Tests to Qualify Three-Terminal Air

Capacitor for Measurement under 521 40C

52160C Fixed Three-Terminal Standard Capacitor with

Coaxial Connectors (1 frequency, laboratory

conditions, 100, 400, or 1000 Hz)

52161C Additional Frequencies

52170C Two- or Three-Terminal Solid Dielectric Standard

Capacitor (66-2/3, 100, 400, 1000, or 10,000 Hz)

52171C Additional Frequencies and/or steps (for decade

capacitors)

52180C Fixed Inductor, Self or Mutual (100, 400, 1000, or

10,000 Hz)

52181C Additional Points

Low-Frequency Capacitance and

Inductance Measurements and

Standards (52110S-52181C)

These services cover the calibration

of standard capacitors and inductors

in the audio-frequency range. Threeterminal standard capacitors having

fused-silica (10 and 100 pF), and gas

(0.001 to 1000 ^iF), dielectrics can be

measured at 100, 400, and 1000 Hz.

Two-terminal capacitors with either

air, mica, or polystyrene dielectrics can be measured at 100, 400, 1000,

and 10,000 Hz. Capacitors in the

range from 1 microfarad to 100 microfarad, including decade (plug or

rotary switch types — noninductive), can be calibrated at 66-2/3, 100, 120,

400, or 1000 Hz. Air-core standard in- ductors having nominal values between 0.01 mH and 10 H can be

measured over the same frequency

range. Standard inductors of 100 mH

or less can also be measured at 10

kH.

Calibration services for some types

of capacitance standards at frequencies as low as 1 kHz can be provided

by the NIST Boulder Laboratory pro- vided the accuracy requirement does

not exceed ±0.01 percent. In some

circumstances this can eliminate the

necessity of sending a standard to both Gaithersburg and Boulder Laboratories for a complete calibration. See also tests 52210C-52310C for cal- ibration services for capacitors at higher frequencies. For additional details please inquire at NIST/Boulder:

Telephone (303) 497-3609.

Special LF Impedance Measurements,

by Prearrangement (52110S)

This service provides for the testing or evaluation of prototype impedance

standards or measurement instrumentation at the state-of-the-art, and

other impedance measurements (such

as the calibration of decade or vari- able capacitance standards), at the

discretion of NIST technical experts.

Component capacitors, inductors, and

120
52110S-52181C

resistors are not considered for test by NIST unless their performance ap- proximates that of the best available

standards. Even under those conditions, only limited testing will be done

to ascertain the possible use of the

components in precision measure- ment applications.

Standard Fixed, Fused-Silica

Dielectric Capacitors

(52130C-52131C)

Fused-silica dielectric standard capacitors are generally submitted in temperature-controlled ovens due to their 10-ppm/degree temperature coefficient. Because of the magnitude of

the temperature coefficient, it is rec- ommended that a reliable temperature sensor having a resolution of

0.001 °C, or better be permanently

mounted in the oven and thus in- cluded for the calibration. For baths

not so equipped, the temperature is measured in terms of the International Temperature Scale of 1990

(ITS-90), using a standard platinum

resistance thermometer.

Calibrations are carried out at 100,

400, or 1000 Hz, or any combination

of these chosen by the client. A minimum of eight measurements are made over a 2-week or longer period,

comparing the test capacitor directly

with a NIST fused-silica standard at 10 pF. The number of readings taken

depends on the stability of the temperature controller in the oven containing the test capacitors and can be

as high as 14. The averages of the

measured values of capacitance and

temperature are reported. The uncertainty of the reported capacitance

value depends on the stability of the

temperature as well as on the perfor- mance of the capacitance standard it- self. Because the temperature

coefficients of individual standards

are not known quantitatively, the results are not temperature corrected.

Despite these factors, the uncertainty can be as low as 0.1 ppm.

Fused-silica dielectric standards not submitted in their own temperaturecontrolled oven are calibrated in

stirred oil at a temperature of 25 °C.

If they are supplied with built-in sensors, the sensors and the bath temperature are both measured.

Standard Capacitors (52140C52171C)

The following guidelines apply to the

calibration of standard capacitors at NIST.

Calibrations are ordinarily per- formed at a normal laboratory ambient temperature of 23 ± 1 °C except

for high-stability gas dielectric capacitors. These are placed in a highly in- sulated chamber for 48 hours to achieve temperature stability during

calibration. The calibration temperature of about 23 °C is reported to within ±0.1 °C. Relative humidity is maintained at 50 percent or less in all cases. Precision three-terminal gas dielectric capacitors, such as ESI Model

SCIOOO and GENRAD Model 1404,

have been found to be variously af- fected by mechanical shock and ori- entation. Accordingly, two types of

calibrations are offered. The higher

accuracy calibration (52140C) re- quires a qualification test (52150C) to determine the effect on capacitance

of various impacts and changes in ori- entation. Results of this test are cou- pled with the random error of the

precision calibration which follows to provide a more complete uncertainty

for the calibration process. For the

lower accuracy test (52160C), a similar calibration, albeit with reduced

resolution, is performed, but no physical testing is performed. The as- signed uncertainty is fixed and has

been deduced from an analysis of

data taken from tests on a large population of standard capacitors.

The frequencies available for ca- pacitance calibrations depend upon

the type of capacitor and its connectors. In general, capacitors with coaxial connectors (Type 900) can be

calibrated at 100, 400, and 1000 Hz.

Capacitors with binding posts or PL

274 pins can be calibrated at 66-2/3,

100, 400, 1000, and 10,000 Hz.

121
The capacitance value given is the

equivalent parallel capacitance. In general, an accurate determination of

the equivalent parallel conductance

with high accuracy is not feasible. However, for solid dielectric capacitors an approximate value is given

without charge.

The uncertainty stated in the re- port of calibration is determined in part by the accuracy of NIST's measurements and in part by the characteristics of the capacitor itself. The

uncertainty is sufficiently broad to al- low for variations in the stray capaci- tance at the connectors, variations in temperature of a few degrees Celsius,

considerable variation in relative humidity and atmospheric pressure, and

frequency deviations of a few percent

from the stated test conditions. Over

the above frequency range, and in the

capacitance range from 0.001 to 100

jjlF, the uncertainty usually lies in the

range 0.0003 to 0.5 percent. The uncertainties do not include allowances

for effects of transportation; these

must be determined by the owner us- ing pre- and post-calibration data

from his own facility.

Capacitors requiring terminal plugs

(banana plugs) for parallel connection

should be sent to NIST, together with

the plugs that will be used with the

capacitor after calibration. If such a capacitor arrives without plugs, NIST

must attach plugs temporarily in or- der to calibrate the capacitor. The

plugs used by NIST are GENRAD

Type 274-P. If, after calibration with

these plugs, the capacitor is used with

plugs of even slightly different length

and base, the capacitance can differ significantly from that reported. Unless otherwise requested, the measured value reported by NIST is the

capacitance added when the standard

is plugged directly into the binding

posts of the NIST bridge. For twoterminal GENRAD capacitors Type

1401, Type 509, and Type 1409 (when

used as a two-terminal capacitor), a capacitance increase ranging from

0.01 to 0.04 pF has been found for different plugs. No significant

change in conductance has been

found in either the two-terminal or

three-terminal value. The importance

of terminal connection methods be- comes extremely critical when capaci- tance values of 0.01 |xF or less are being measured. Improved accuracy

in two-terminal measurement can be

realized if standards are provided

with precision coaxial connectors.

In the case of direct or threeterminal capacitance standards, the connectors are assumed to be coaxial. While the connectors available for

this purpose are adequate, it should

be noted that changes or instabilities

in the impedance of the shield or guard connection of a three-terminal

capacitor can change the capacitance

significantly.

Unless otherwise specified in the customer's purchase order, capacitors

with solid dielectric — except for

fused-silica capacitors— will be cali- brated as two-terminal capacitors

(measurement of "grounded" capacitance, case connected to low terminal).

Standard Inductors, Self or Mutual

(52180C-52181C)

Standard inductors for use in ac

bridges are tested at a room temperature of 23 °C and a relative humidity

of 50 percent or less. Measurements

at 10,000 Hz are limited to standard

inductors of 0.1 H or less. Most in- ductors used at 60 Hz can be tested

at 100 Hz since the variation of in- ductance with frequency in this range

is usually negligible. A metal-encased

standard is calibrated with the case connected to the "low" terminal of

the inductor unless other conditions

are specified.

122
521]0S-52181C

References — Low-Frequency Capacitance and Inductance Standards

New Realization of the Ohm and

Farad Using the NBS Calculable

Capacitor, J. 0. Shields, R. F. Dziuba, and H. P. Layer, Conf.

Precision Electromagnetic Meas.

(CPEM '88), June 7-10, 1988,

Tsukuba Science City, Japan,

Special Issue CPEM '88 IEEE

Trans. Instrum. Meas., Vol. 38,

No. 2, 249-251 (April 1989).

Testing to Quantify the Effects of

Handling of Gas Dielectric Stan- dard Capacitors, C. R. Levy, Natl. Bur. Stand. (U.S.), Tech. Note

1161 (1982).

Transportable 1000 pF Standard,

G. M. Free and J. J. Morrow, Natl. Bur. Stand. (U.S.), Tech. Note

1162 (1982).

New Measurements of the Absolute

Farad and Ohm, R. D. Cutkosky,

IEEE Trans. Instrum. Meas.,

IM-23, No. 4, 305 (Dec. 1974).

Applications of Coaxial Chokes to AC Bridge Circuits, D. N. Homan,

J. Res. Natl. Bur. Stand. (U.S.),

72C, No. 2 (June 1968).

Improved Ten-Picofarad Fused Silica Dielectric Capacitor, R. D.

Cutkosky and H. L. Lee, J. Res.

Natl. Bur. Stand. (U.S.), 69C, No.

3, 173 (Sept. 1965).

Calibration of Inductance Standards

in the Mcixwell-Wein Bridge Circuit, T. L. Zapf, J. Res. Natl. Bur. Stand. (U.S.), 65C, No. 3 (Sept.

1961).

Capacitance Bridge — NBS Type 2, R. D. Cutkosky, Natl. Bur. Stand.

(U.S.), Report 7103 (Mar. 1961).

123
52210S-52310S

B Impedance Measurements (Except Resistors)

B.2 High-Frequency Standard Capacitors

and Inductors

Technical Contacts:

G«orge M. Free Kathy Hillen

Tel: 303/497-3609 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 52210S Two-Terminal, Low-Loss Standard Capacitors —

10 kHz to 250 MHz; 1 pF to 1 |jlF 5221 IC Two-Terminal, Low-Loss Standard Capacitors

(High Accuracy) -1 MHz; 50, 100, 200, 500,

and 1000 pF

52220S Three-Terminal, Low-Loss Standard Capacitors —

100 kHz, 1 MHz; 10"^ pF to 10^ pF

52221C Three-Terminal, Low-Loss Standard Capacitors

(High Accuracy) -100 kHz, 1 MHz; 10"^ 10"

\

1, 10, 10^ and 10^ pF

52310S Two-Terminal, High-Q Standard Inductors (10-2 iiH to 1 H)

High-Frequency Standard Capacitors

and Inductors (52210S-52310S)

Services provided in this category

(and also Test Nos. 51310S and

52700C) are for passive devices over

the frequency range from 10 kHz to 250 MHz. Highest accuracy is obtained only for standards equipped

with precision coaxial connectors. Standards submitted for calibration

should be in good repair and, except

for very minor cleaning of connector

surfaces, should require no precalibration maintenance. NIST does

not provide repair services; items re- ceived that require maintenance will be returned to the sender and a handling fee charged.

Calibration services for some types

of capacitance standards at frequencies as low as 1 kHz can be provided

by the NIST Boulder Laboratory pro- vided the accuracy requirement does

not exceed ±0.01 percent. In some

circumstances this can eliminate the

necessity of sending a standard to both the Gaithersburg and Boulder

Laboratories for a complete calibration. For additional details please

consult with the technical contact

listed at the beginning of this section. Calibration service for measuring

instruments such as bridges or meters

is not provided. The accuracy of these

instruments should be verified by the owner through the use of stable stan- dards especially selected for particular values and frequencies

appropriate to the instrument in question.

All calibrations are performed under typical ambient laboratory conditions of 23 °C, and an atmospheric

pressure of approximately

8.4 ± 0.2 X 10^ Pa at Boulder, Colorado. Services at ambient conditions

outside these limits are not provided.

Also, the power applied to any device

being calibrated does not exceed 1 W.

Additional information pertaining to immittance (impedance and admittance) measurement and standards is contained in the references.

Two-Terminal, Low-Loss Standard

Capacitors (52210S-52211C)

In the frequency range from 10 kHz

to 250 MHz, capacitance calibrations

to a minimum uncertainty of ±0.1

percent are available from 1 pF to 1 |xF depending upon frequency. The

upper capacitance limit for calibra- tion decreases as the frequency in- creases and is 50 pF at 5 MHz and

above.

124
52210S-52310S

At 1 MHz a special high-accuracy

service is available for capacitors with

nominal values of 50, 100, 200, 500,

and 1000 pF provided they are equipped with 14-mm coaxial connectors. Reports of calibration for capacitors normally do not give conductance

values. This is because capacitors of

standard quality, especially those with

air-dielectric, have conductance val- ues too small to be measured accurately at the present state-of-the-art. A technique for extrapolating the

1-kHz values of capacitance standards

to high frequencies is described by

R. N. Jones (see references). This

reference describes a technique for obtaining a high-frequency value of a capacitor equipped with an unshielded (banana plug) connector. The measurement technique yields ef- fective capacitance values at high fre- quencies using the capacitance value

at 1 kHz and the residual series in- ductance. The same technique, with some modifications, is usable for three-terminal and four-terminal pair

capacitors. It is emphasized that these

extrapolation procedures are only us- able for air dielectric capacitors or

capacitors with insulating materials

whose dielectric constant does not change with frequency.

Three-Terminal, Low-Loss Standard

Capacitors (52220S-52221C)

Fixed-value reference standards are maintained by NIST for values of 10,

100, and 1000 pF. High-quality three- terminal air dielectric capacitance

standards should have low residual

series inductance (<0.1 ixH). This

being the case, it may be assumed

that to an accuracy of ±0.10 percent,

the capacitances of standards of 1 pF

or less with air dielectric is the same

at 1 MHz as it is at 1 kHz. Thus, it is unnecessary to have capacitors

smaller than 10 pF calibrated at

1 MHz,

Two-Terminal, High-Q Standard

Inductors (523 lOS)

In the frequency range from 10 kHz

to 250 MHz, inductance calibrations

to a minimum uncertainty of ±0.1

percent are available from 0.01 p,H to

1 H. The upper inductance limit for calibration decreases as the frequency

increases and is 1 \i,H at 250 MHz. In the Report of Calibration, the resis- tance of the inductor is also given.

Service is available only for aircore

inductors or inductors whose value is independent of current.

References — High-Frequency Stan- dard Capacitors and Inductors

Evaluation of Three-Terminal and

Four-Terminal Pair Capacitors at High Frequencies, R. N. Jones,

Natl. Bur. Stand. (U.S.), Tech.

Note 1024 (Sept. 1980).

The Measurements of Lumped

Parameter Impedance: A Metrology Guide, R. N. Jones, Natl. Bur.

Stand. (U.S.), Monogr. 141 (June

1974).

A Precision High-Frequency Calibration Facility for Coaxial Capacitance Standards, R. N. Jones and

L. E. Huntley, Natl. Bur. Stand.

(U.S.), Tech. Note 386 (Mar. 1970).

Impedance of Lumped Circuits, L. E. Huntley and R. N. Jones, Proc. IEEE 55(6), 900 (June 1967).

A Technique for Extrapolating the

1 kc Values of Secondary Capacitance Standards to Higher Frequencies, R. N. Jones, Natl. Bur.

Stand. (U.S.), Tech. Note 201

(Nov. 1963).

125
52400C

B. Impedance Measurements (Except Resistors)

B.3 Power-Frequency Capacitors

Technical Contacts:

James K. William E. OlthofT Anderson

Tel: 301/975-2431 Tel: 301/975-2423

Mailing Address: B344 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

[Attn: J. K. Olthoff, Bldg. 202, Room 167]

References — Power-Frequency

Capacitors

A Calibration Service for Voltage

Transformers and High-Voltage

Capacitors, W. E. Anderson, Natl. Bur. Stand. (U.S.), Spec. Publ.

250-33 (June 1988).

An International Comparison of

High-Voltage Capacitor Calibrations, W. E. Anderson, R. S. Davis,

O. Petersons, and W. J. M. Moore,

IEEE Trans. Power Appar. Syst., 97, 4, 1217 (July 1978).

A Wide Range High-Voltage Capacitance Bridge with One-ppm Accuracy, O. Petersons and W. E. Anderson, IEEE Trans. Instrum. Meas., IM-24, 4, 336 (Dec. 1975).

Test No. Items 52400C Power-Frequency Capacitors

Power-Frequency Capacitors

(52400C)

A calibration service is maintained

for capacitors designed for 60-Hz operation, especially at voltages above

100 V. Typical uncertainties for a cal- ibration are ± 100 ppm of the capacitance, and ± 1 percent of the

dissipation factor ± 1 x 10"^. Routine

calibrations are limited to devices

with a dissipation factor of 0.011 or

smaller and which are operated at sufficient voltages that at least 40 |jiA passes through the device under test. The high-power limit for routine

tests is 10 kVA. Some capability to perform tests outside of these limits

exists, and NIST should be contacted

to discuss special arrangements for such tests.

126
52710C-52711C

B. Impedance Measurements (Except Resistors)B.4 Q-Standards

Technical Contacts:

G«orge M. Free Kathy Ilillen Tel: 303/497-3609 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Estimated limits of uncertainty are based upon a statistical analysis of

previously obtained calibration data. These uncertainties are believed to result solely from sources of random

error as opposed to known systematic

errors.

References — Q-Standards

Standards for the Calibration of

Q-Meters, 50 kHz to 45 MHz,

R. N. Jones, J. Res. Natl. Bur. Stand. (U.S.), 58C, No. 4, 243

(Oct.-Dec. 1964).

Test No. Items 52710C Inductive Q-Standards; 50 kHz^5 MHz, 0.25 (xH to 25 mH

5271 IC Each Additional Frequency for 52710C

Q-Standards (52710C-52711C)

Standards for Q-measurements are maintained at NIST. These are high0 inductors equipped with banana

plug connectors at a spacing of

1 inch on centers. These standards

have inductance values of 0.25, 2.5, 25, 250, 2500, and 25,000 |jlH, and ef- fective Q-values from 100 to approximately 600. These serve as working

standards for calibration of Qstandards of a similar type. Calibration frequencies range from 50 kHz

to 45 MHz. The calibration report in- cludes effective resonating capaci- tance and effective Q. Uncertainties

are of the order of ±0.2 percent for capacitance and 2 percent for Q. Provisions are made for calibrating each

0-standard at three frequencies; however, adequate assurance of stability

is usually provided by recalibrating

only at the center frequency.

127
53110S-53190S

C. Voltage Measurements

C. 1 DC Voltage Measurements

and Standards

Technical Contacts:

June E. Sims

Tel: 301/975-4238 Richard L. Steiner

Tel: 301/975-4226 Norman B. Belecid

Tel: 301/975-4223

Denise D. Prather

Administrative and Logistics

Tel: 301/975-4221

Mailing Address: B146 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items

531 lOS Special DC Voltage Measurements, by

Prearrangement

53120M Measurement Assurance Program for DC Voltage

53130C First Saturated Standard Cell in a Group

53131C Each Additional Cell 53140C Platinum Resistance Thermometer Temperature

Determination for Standard Cell Calibration 53150C Unsaturated Standard Cells 53160C Tests of Solid-State Voltage Reference Standard

(1 Output, 1-10 V)

53161C Each Additional Output

53180S Special Handling (Equipment Pickup or Delivery)

53190S Special Handling (Cleaning, Minor Repair, Return

Service Charge)

General Information — DC Voltage

Measurement Standards

The service described in this section

provides for the calibration of stan- dards of direct voltage, saturated and

unsaturated standard cells, and solid- state standards, and for dc voltage

MAP services at the 1.02-volt level. The U.S. Representation of the Volt

is maintained by monitoring the emfs of several groups of saturated stan- dard cells in ovens on a monthly basis

using the ac Josephson effect.

Customer cells are calibrated by measuring the difference between their emfs and those of working groups of

standard cells using automated sys- tems comprised of low thermal emf,

computer-controlled switches and

high-resolution digital voltmeters.

Figure 9 summarizes the uncertainty of NIST dc voltage measure- ments for the primary standards,

standard cells, and Zener diodes.

Figure 9. Uncertainties of NIST DC Voltage

Measurements

5x108

108

5x10^ -

10'

S 5x10^

10^

5x10^

-Primary Cells

Zener

Diodes /

- Standard

Cells

10^ DC Voltage10^

Special DC Voltage Measurements, by

Prearrangement (53110S)

The evaluation, testing, or calibration

of prototype dc voltage standards and

measuring apparatus or unique

voltage measurements are provided

for in this service. These measure- ments are performed only when

deemed reasonable by the appropriate technical staff and serving the

best long-term interests of the client,

the measurement community, and

NIST.

128
53110S-53190S

Measurement Assurance Program

Service (53120M)

This MAP service provides a measurement of the error of dc voUage

measurements in the customer laboratory at the 1.02-volt level, the uncertainty of the results, and an updated assigned value for the

client's reference standards. A trans- port standard, which consists of a standard cell enclosure containing

four saturated standard cells, maintaining constant temperature via line and battery power, is used. It is preferentially hand-carried between NIST

and the client laboratory, but ar- rangements may be made for air shipment. The standard is calibrated by

NIST, the customer laboratory, and

again by NIST to obtain the required

data. The transport standard is capable of performing at the 0.2- to 0.3- ppm level of reproducibility when

hand-carried, 0.5 to 0.8 ppm otherwise.

The measurement uncertainty

achieved in this service contains primarily random errors. The major

components of random error can be

attributed to:

A. Day-to-day fluctuations in temperature-corrected cell emfs caused

by temperature-hysteresis effects; B. The finite resolution of the

measurement apparatus at both the

client laboratory and NIST;

C. Thermal emfs, unstable with

time, which occur in the measuring

circuit due to room temperature and

humidity changes and drafts; D. Temperature coefficients of

the enclosures as a whole, not compensated for by temperature corrections; E. Lack of resolution or instability

of the apparatus used to monitor the

cell temperatures;

F. Slow changes in temperature

gradients or enclosure temperatures

possibly due to atmospheric "pumping" of cool air into the enclosures, or vibration effects on the control cir- cuitry;

G. Controller instability caused by

power-line noise; H. Effects of electrostatic or elec- tromagnetic pick-up on the measuring

system;

I. Detector drift; and

J. Momentary upsets in cell emfs

caused by small electrical currents passing through the cells. The experimental design described

for making the intercomparison measurements removes the effects of av- erage "left-right" or offset errors. One potentially significant source of

error not corrected for or quantified

in the MAP service is that caused by

scale-factor errors in the instrumentation used to measure the differences

between cell emfs. An error from

this source can be eliminated by using

calibrated instruments and applying

the appropriate calibration corrections to the results. The transport standard is normally

kept in the client's laboratory for about 4 weeks, as 8 to 12 measure- ment sets are generally required.

Data analysis and issuance of the test report by NIST takes 4 to 5 weeks

following the return of the transfer standards.

If the participating laboratory has a

quality instrument that has been ac- curately calibrated and also has quality standards, the uncertainty of a

single transfer of the unit of voltage

using NIST transport standards is generally of the order of 0.5 ppm or

better. The best achievable long-term

uncertainty, resulting from five or more transfers over an extended time,

is of the order of 0.2 to 0.3 ppm.

In this service, NIST provides detailed instructions for carrying out the

transfer and making the required

measurements. The participant must

have in-house standards and instru- mentation capable of sustained per- formance at the 0.1-ppm level. When

a new participant (or group of participants) expresses a desire to use the

129
voltage MAP service, NIST requests

that a complete description of the

participant's measurement system, in- cluding instruments, standards, wires,

switches, and their use, be sent to the

NIST technical staff. This description

enables NIST personnel to assist in resolving measurement problems by

telephone.

NIST requires evidence in the form

of control charts of the existence of a formal quality-control program in the

laboratory as a prerequisite to participation in the service. This requirement has been established to enable

problems to be addressed in advance

of the transfer and to reduce delays

in returning the standards to NIST.

Saturated Standard Cells (53130C-53140C)

Routine calibrations of saturated

standard cells involve the following

considerations:

A. Saturated standard cells of the

unshippable type should always be

transported by messenger because

such cells should never be tipped

from an upright position by more

than 45° in any direction. Unshippable saturated cells contained in portable, temperature-regulated enclosures should also be transported by

messenger and with the enclosure ac- tivated or under power if possible. B. Saturated standard cells of the

shippable type housed in portable

thermoregulated enclosures should be

packed carefully and shipped under

power if possible. Any liquid-in-glass

thermometer mounted in such a device should be removed and pro- vided with additional rigid packing for protection against breakage. Enclosures having a nominal cell temperature of 28 °C or lower should not be

transported during the summer due

to the danger of overheating. Enclosures should not be energized by us- ing the ac power mains while they are

in shipping containers as heat from

the transformer will cause them to go

over-temperature.

C. Saturated standard cells, which

are maintained continuously at their

nominal temperature of use during

shipment, will undergo test starting 1 week after receipt for a period not to exceed 6 weeks, unless other arrange- ments are made. If such cells perform

abnormally, the owner will be notified. Arrangements for further testing

may be made at that time if desired.

Cells will be returned as soon as possible after calibration. D. Saturated cells arriving at a temperature other than their nominal

temperature of use will be brought to their use temperature as soon as possible after receipt. Starting 1 month

after they initially attain use temperature, daily readings will be taken to observe the stability of the cells. When the cells stabilize, 10 daily

readings will be taken and averaged

to assign values to them. This process

will not exceed 90 days without special arrangements being made.

E. For an additional fee, the temperature of air bath enclosures for saturated standard cells will be determined using a calibrated NIST platinum resistance thermometer (test 53140C). Daily readings are taken

and reported. The reported cell emfs are assumed to correspond to the mean of the temperatures measured

on the same days as the emf readings were taken. The client must understand that, when this is done, the uncertainties of the reported emfs include the emf equivalent of the uncertainty of the measured temperatures in terms of the International

Temperature Scale of 1990 (ITS-90).

Moreover, estimates of the uncertainties of any voltage measurements

made by clients using these cells as a reference must include corresponding

uncertainties of their own temperature measurements.

F. NIST accepts cells used in oil baths for calibration in NIST oil baths maintained at 28 and 30 °C. Cells used in oil baths operating at other nominal temperatures can best

130
53110S-53190S

be calibrated using transport stan- dards as in the MAP service. (See

53120M above.)

Calibration uncertainties generally

range from 0.3 to 0.75 ppm. The

stated uncertainties are those of the

NIST-measured average values, i.e., they do not reflect long-term behavior

of the cells, transportation effects,

etc.

Unsaturated Standard Cells (53150C)

Unsaturated cells require approximately 3 weeks for a complete cali- bration. The emfs of such cells are read daily for a minimum period of

10 days. These cells are compared

with NIST saturated cells using a precision digital voltmeter to measure

the difference emf directly. The cali- bration uncertainty is 0.005 percent of

the measured voltage unless the cell

is abnormal. If the measured emf

fluctuates unduly or is unusually low, or if the cell behaves abnormally, the

reported uncertainty will be increased

appropriately. Unsaturated cells are not likely to be injured by normal

transportation (mail or express) if they are packed carefully. Because of

the possible hazard from freezing,

shipment during extremely cold

weather should be avoided.

Solid-State Voltage Reference

Standards (53160C and 53161C)

Solid-state voltage standards with out- puts in the range from 1 to 10 volts are calibrated using a self- calibrating automated system which

scales to any multiple up to 10 of

1.018 volts from the emf of a working

group of NIST saturated standard

cells. It then measures the difference

between the emf of the standard un- der test and the emf of its own out- put closest in voltage to that of the

standard being measured and computes its emf. Measurements are taken daily for 12 to 15 working days

and the mean value of the results reported.

Because of the limited battery life of many commercial standards, special shipping arrangements are advis- able and can be made by contacting

the Electricity Division.

Many solid-state standards have

multiple outputs; the outputs to be

calibrated should be specified on the

shipping papers as well as on the pur- chase order to ensure proper testing.

Voltmeter calibrators, multirange

instruments with up to eight decimal

digits of adjustability, are not considered by NIST to be standards and are not to be submitted routinely for cali- bration under this test category. Likewise, NIST will not accept component solid-state devices for routine

calibration. However, new, state-of- the-art devices and instruments may

be accepted for test under special cir- cumstances (see test 531 lOS) at the

discretion of NIST technical staff.

The NIST calibration service for voltage is directly tied

to NIST Josephson-junction voltage-standard arrays. This 1-V standard fabricated from niobium trilayer re- sists the effects of cycling between its operating temperature of liquid helium and room temperature better than previous designs.

131
References— Voltage Measurements

and Standards

Guidelines for Implementing the New

Representation of the Volt and

Ohm Effective January 1, 1990, N.

B. Belecki, R. F. Dzuiba, B. F. Field, and B. W. Taylor, Natl. Inst. Technol., Tech. Note 1263 (June

1989).

NBS Measurement Services: Solid- State DC Voltage Standard Calibrations, B. F. Field, Natl. Bur.

Stand. (U.S.), Spec. Publ. 250-28

(Jan. 1988).

NBS Measurement Services: Stan- dard Cell Calibrations, B. F. Field, Natl. Bur. Stand. (U.S.), Spec.

Publ. 250-24 (Oct. 1987).

The NBS Josephson Array Voltage

Standard, C. A. Hamilton R. L. Kautz, F. L. Lloyd, R. L. Steiner,

and B. F. Field, IEEE Trans. lu- strum. Meas., IM-36, 258 (June

1987).

A Sub-PPM Automated One-to-Ten

Volt Measuring System, B. F. Field,

IEEE Trans. lustrum. Meas., IM34, 327 (1985).

Volt Transfer Program Instructions,

NBS Internal Document, Unpublished, Revised (1983).

A High-Resolution Prototype System

for Automatic Measurement of

Standard Cell Voltages, D. W.

Braudaway and R.E. Kleinmann,

IEEE Trans. lustrum. Meas., IM23, 282 (1974).

Volt Maintenance at NBS via 2e/h:

A New Definition of the NBS Volt,

B. F. Field, T. F. Finnegan, and

J. Toots, Metrologia, 9, 155 (1973).

Designs for Surveillance of the Volt

Maintained by a Small Group of

Saturated Standard Cells, W. G.

Eicke and J. M. Cameron, Natl. Bur. Stand. (U.S.), Tech. Note 430

(Oct. 1967).

Standard Cells— Their Construction,

Maintenance, and Characteristics,

W. J. Hamer, Natl. Bur. Stand.

(U.S.), Monogr. 84 (Jan. 1965)

132
53200S-53201S

C Voltage Measurements

C.2 AC Voltage Measurements

Technical Contacts:

Nile M. Oldham Barry A. Bell Mark E. Parker

Tel: 301/975-2408 Tel: 301/975-2419 Tel: 301/975-2413

Mailing Address: B162 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 53200S Special Tests of High-Accuracy AC Digital

Multimeters, Multifunction Calibrators,

by Prearrangement

53201S Special Tests of Low-Voltage AC-DC Transfer

Standards, by Prearrangement

Digital Multimeters (DMMs) and

Multifunction Calibrators (53200S)

AC Voltage measurements are per- formed at frequencies between 0.1 Hz

and 30 MHz at amplitudes between 1 mV and 1 kV in the mid-frequency

range. Low-frequency measurements (0.1 to 10 Hz) are made using a NIST-developed calculable voltage standards

in which waveforms are digitally syn- thesized using a sine lookup table and

a pair of digital-to-analog converters. The resulting "stepped" waveform is measured at very low frequencies us- ing a precision dc voltmeter. This

source may be used in conjunction

with external attenuators to calibrate

DMMs between 1 mV and 7 V. Wideband measurements between

10 Hz and 30 MHz are made using a thermal voltage converter (TVC)

based automatic calibration system.

Using this system, ac calibrators and

DMMs are tested from 100 mV to 1 kV. At lower levels, a micropotentiometer is used (as an ac-dc transfer

standard) to generate voltages between 1 and 100 mV that are used to calibrate DMMs (calibrators are

tested using a characterized DMM).

The estimated uncertainties associ- ated with both measurement systems

range from ± 10 ppm in the midvoltage and mid-frequency range to ±0.2 percent for a 1 mV measure- ment at 1 MHz.

AC current measurements are per- formed on the same system using a

set of characterized thermal current

converters. Current sources can be

measured from 10 Hz to 100 kHz at current levels between 1 mA and 2 A.

Due to limitations in the present

NIST sources, DMM tests are nor- mally limited to an upper frequency

of 5 kHz; however, special arrange- ments may be made for tests at higher frequencies and currents. The

best uncertainties available for ac cur- rent measurements are less than

± 100 ppm.

Measurements of dc voltage (1 mV

-1 kV), dc current (10 iiA-2 A),

and resistance (10 Cl-10 Mil), for both DMMs and calibrators, are being offered on a trial basis. These

tests are performed using calibrators

and DMMs which have been carefully

characterized using standards maintained in the Electricity Division. The

best uncertainties are less than ±3

ppm for certain values of dc voltage

and resistance.

Low-Voltage AC-DC Transfer

Standards (53201S)

Measurements of the ac-dc difference

of low-voltage thermal transfer stan- dards, micropotentiometers, and

voltage dividers is also offered on a

trial basis. High-accuracy tests on

these devices are performed, using a procedure described in New LowVoltage Standards in the DC to 1 MHz Frequency Range (see refer- ences), between 1 and 200 mV from

dc to 1 MHz where uncertainties of

±20 ppm are possible in the audiofrequency range at 100 mV.

133
53200S-53201S

References— AC Voltmeters and

Sources

New Low-Voltage Standards in the

DC to 1 MHz Frequency Range,

N. M. Oldham and R. M. Henderson, Conf. Record of CPEM '90, Ottawa, Canada (June 1990).

A Calculable, Transportable AudioFrequency AC Reference Standard,

N. M. Oldham, P. S. Hetrick, and

X. Zeng, IEEE Trans. Instrum. Meas., Vol. 38, No. 2, pp. 368-371

(April 1989).

A High-Accuracy, 10 Hz-1 MHz Automatic AC Voltage Calibration

System, N. M. Oldham, M. E. Parker, A. Young, and A. G.

Smith, IEEE Trans. Instrum. Meas., IM-36, pp. 883-887 (Dec.

1987).

134
53310S-53341C

C Voltage Measurements

C.3 AC-DC Thermal Voltage and Current

Converters (to 1 MHz)

Technical Contacts:

Joseph R. Kinard Norman B. Denise D.

Tel: 301/975-4250 Belecki Prather

Tel: 301/975-4223 Administrative and Lx)gistics Tel: 301/975-4221

Mailing Address: B146 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 53310S Special AC-DC Measurement Services,

by Prearrangement

53340C AC-DC Thermal Voltage and Current Converters

(1 voltage, 1 frequency from 2 Hz to 1 MHz)

53341C Additional Determination at 1 Frequency

(from 2 Hz to 1 MHz)

General Information— Thermal

Voltage and Current Converters

Routine calibrations of thermal

voltage and current converters generally are carried out on a demand

basis. However, occasional extensive

calibration requests may create scheduling problems; therefore, to

facilitate rapid turnaround, please

advise D. D. Prather at the telephone

number/address cited above before

sending the equipment.

Calibration services for widefrequency range thermal voltage converters, such as John Fluke Model

A55 or HP 11000 series, have been

extended in the NIST Boulder Laboratory to cover frequencies down to 100 Hz with uncertainties as low as 0.05 percent (see tests 53405S53420C). This means thermal converters of this type can be completely

calibrated at NIST Boulder if the

0.05 percent uncertainty is acceptable.

Calibration requiring uncertainties

less than 0.05 percent in the range

below 1 MHz continue to be done in NIST Gaithersburg (53310S-53341C).

Special AC-DC Measurement Services, by Prearrangement (53310S)

This service provides for the measure- ment or evaluation of prototype ac

voltage or current standards, sources, or measurement instrumentation, and

for other measurements of alternating

voltage, alternating current, or ac-dc

difference not provided for below, at the discretion of NIST technical experts. Components used for ac-dc

conversions will generally not be

tested unless they show promise of

standards-level behavior. Even then,

such components will only be tested

in very limited numbers to explore

their possible use for precision measurements.

Special ac-dc difference calibrations

of appropriate thermal voltage and

thermal current converters are now

offered with an uncertainty of 0.8 ppm. This sub-part-per-million cali- bration service is the result of an ex- tensive study of the group of

multijunction thermal converters that make up the NIST primary standards.

Thermal converters will be accepted

for calibration with the 0.8 ppm uncertainty providing their performance,

including stability and square-law re- sponse, is compatible with the NIST

standards and high-precision comparator system. In general, the subppm uncertainty is available for voltages from 2 to 12 V, currents from 5 to 20 mA., and frequencies

from 30 to 10 kHz. As in the case of

the other special ac-dc difference cal- ibrations with reduced uncertainty, an

additional cost and a longer-thanusual turnaround time at NIST are

required. Prospective clients are asked to contact Joseph Kinard,

phone (301) 975-4250, to discuss the

requirements and arrangements re- lated to this service.

135
AC-DC Thermal Voltage and Current

Converters (Up to 1 MHz)

(53340C-53341C)

This service covers the calibration of

thermal voltage and current converters, ac shunts, and primary ther- moelements covering the ranges 2 Hz

to 1 MHz, 1 mA to 20 A, and 0.5 to 1000 V. These are used to make measurements of alternating current and

voltage in terms of direct current standards of voltage and resistance

and are calibrated at NIST by comparison with similar NIST devices.

Ordinarily only ac-dc transfer stan- dards and thermal converters of 0.05 percent or better rated accuracy are accepted for test. AC-DC difference

tests consist of determinations of the

differences between the current or

voltage, required to give the same re- sponse (output) of the transfer stan- dard for alternating current and for the average of the two directions of

direct current. Tests are recom- mended at rated voltage or current on each range up to the highest fre- quency of interest. For 1000-V

ranges, a second test at 600 V is recommended because these ranges

may be affected by self-heating. In addition to the high-frequency tests, an ac-dc difference test (ordinarily at 20 Hz) is recommended for one

range, to verify the low-frequency ac- curacy. Thermoelements have a lowfrequency limit, below which they fail to integrate properly. The ac-dc dif- ference may approach 0.02 percent at frequencies ranging from about 5 Hz,

for most low-range thermoelements,

to about 60 Hz, for some thermoelements with ratings above 1 A.

This low-frequency ac-dc difference

is nearly the same for all ranges of a multirange converter in which a

single thermoelement is used with

shunts or multipliers. For convenience, usually a low-voltage or cur- rent range is chosen for the test. Unless the test points have been

firmly established in prior practice.

the user is strongly advised to contact

the appropriate NIST technical staff prior to submission of the standards to NIST for calibration.

Thermal voltage and converters are used to make

accurate ac to dc transfer measurements. To improve

the Nation's capability to make these measurements,

NIST is investigating multijunction thermal converters made using thin-film technology developed for the

semiconductor industry. An experimental NIST device

is shown.
53310S-53341C

Table 15: AC-DC Difference Calibration Service

Frequency: 2-5 5-20 20-20k 20-50 50-100 0.1-1 Hz Hz Hz kHz kHz MHz

Voltage

Limits (V) 50 100 1000 1000 1000 100 Current

Limits (A) 0.05 0.05 20 20 2^"^

Uncertainty (parts per million)^''^ Multirange TVC's > 100 V 30 50 70 « 100 V 200f"l loot"! 20 30 50 100 Coax Single Range

TVC's > 100 V 20 30 50

5 V ^ X $ 100 V 200f"^ lOtf^l 15f'] 25 40 70

Specialt''! 10 V :S X ^ 100 V 10 2V^x:SlOV 5 TCC's > 5 A 100 150 50 mA < X ^ 5 A 50 70 ^ 50mAf=J 200 100 50 70

Available as a special test with uncertainty determined on an individ- ual basis.

'''^ The lower uncertainty applies at the crossover frequencies. Uncertainties may be increased if the ac-dc differences are large or affected by

self- heating or other instability. 20 ppm from 20 Hz to 100 Hz, 15 ppm at 100 Hz and above.

'''^ Normally available by prearrangement for coaxial, single-range TVC's

between 100 Hz and 20 kHz. An additional cost and a longer turnaround

time at NIST are required.

^^^This area is currently under study and improvements are expected from time to time. The laboratory staff should be contacted for up-to- date information.

References -AC-DC Thermal

Converters (to 1 MHz)

Determination of AC-DC Difference

in the 0.1-100 MHz Frequency

Range, J. R. Kinard and T. X. Cai,

IEEE Trans. Instrum. Meas., IM38, No. 2, 360 (April 1989).

Recharacterization of Thermal

Voltage Converters after Thermoelement Replacement, J. R. Kinard and T. E. Lipe, IEEE Trans. Instrum. Meas., IM-38, No. 2, 351

(April 1989).

NIST Measurement Services: AC-DC

Difference Calibrations, J. R.

Kinard, J. R. Hastings, T. E. Lipe,

and C. B. Childers, Natl. Inst. Stand. Technol., Spec. Publ. 250-27

(May 1989).

137
53405S-53445S

C Voltage Measurements

C.4 RF-DC Thermal Voltage and Current

Converters (100 Hz-1 GHz)

Technical Contacts:

Gregorio Kathy Hillen Rebuldela Administrative

Tel: 303/497-3561 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items Test No. Items 53405S Special Tests of AC Thermal Voltage Converters,

by Prearrangement

53410C Low-Frequency TVC Calibration at One Frequency

Selected from Those Given in Table 16 at Rated

Voltage in the Range 0.1-50 V

5341 IC Additional Frequency Selected from Table 16 for Same TVC as in53410C

53412S Same as 53410C, Except Customer Designates a Single Frequency (in Same Frequency Range) Other

Than Those Given in Table 16 53413C Low-Frequency TVC Calibration at One Frequency

Selected from Those Given in Table 16 at Rated

Voltage in the Range 50-200 V

53414C Additional Frequency Selected from Table 16 for Same TVC as in53413C

53415S Same as 53413C, Except Customer Designates a

Single Frequency (in Same Frequency Range) Other

Than Those Given in Table 16

53420C High-Frequency TVC Calibration at One Frequency

Selected from Those Given in Table 17 at Rated

Voltage in the Range 0.1-7.5 V

53421C Additional Frequency Selected from Table 17 for Same TVC as in 53420C

53430S Peak-to-Peak Detector Calibration at One Frequency

Selected from Those Given in Table 18 at 1.2 V

Applied RF Voltage

5343 IS Additional Frequency for Peak-to-Peak Detector in Test 53430S

53440S Special Tests of RF Micropotentiometers, by

Prearrangement

53441C RF Micropotentiometer Calibration at One

Frequency Selected from the Frequency Bands

Given in Table 19 53445S Special Calibration of RF Micropotentiometer

(Output Voltage Range, 200 to 200,000 ^.V at Frequency Range, 0.05 to 1000 MHz) with Reduced

Limits of Uncertainty

General Information -RF-DC Thermal Voltage and Current Converters,

100 Hz to 1 GHz (53405S-53445S)

Services are available for three types

of electromagnetic voltage measuring

devices: (1) Thermal Voltage Converters (TVC's), (2) Peak-to-Peak

Detectors, and (3) Voltage Comparators and one type of electromagnetic

generating device: RF Micropotentiometers.

138
53405S-53445S

Past calibrations of micropots and

TVC's have shown that these devices are very stable for periods up to 10

years. Thus, in most cases, a 2-year or longer recalibration cycle is recom- mended. An exception might be micropots whose rated output voltages are 100 jjlV or less. Assurance of device stability can be

obtained by intercomparing a micropot or TVC with another similar

device where voltage ranges overlap.

For example, a 1 V TVC can be compared with a 3 V TVC at 1 V, etc. TVC calibrations requiring uncertainties less than 0.05 percent below

1 MHz are performed at NIST

Gaithersburg. See tests 53310S53341C.

RF Voltage Comparators (53405S)

Special tests are performed on rf voltage comparators using TVC's and

micropotentiometers at selected fre- quencies from 100 kHz to 1 GHz at voltages ranging from 10 mV to 20 V.

Several calibration options are avail- able to the customer. Therefore, consultation by telephone or written

correspondence is recommended before the comparator is submitted for calibration. Thermal Voltage Converters

(53410C-53421C)

Thermal voltage converters also in- clude other devices such as Rawson rf voltmeters, thermal transfer stan- dards, rf voltage standards, and ac-dc

transfer standards.

Most converters have rf-dc differ- ences within ± 0.01 percent of zero at

1 MHz and below. Converters with

previous calibration history that are submitted for recalibration should be

evaluated at 1 MHz and results compared to prior data. If the difference

is negligible, no further calibrations are usually necessary below 1 MHz.

The quantity measured by this cali- bration service is the rf-dc difference,

defined as the percentage difference

between the rf and dc input voltages

required to produce the same ther- mocouple output, e.g.,

rf-dc difference (%) =

(

^"^y^^"' ) x 100.

Services available for low-frequency

TVC's without a built-in "T" connector are given in Table 16. For highfrequency TVC's with a built-in "T"

connector, the services available are given in Table 17. Calibrations above

100 MHz are performed only on the new high-frequency thermal voltage converters with a "T" connector

as an integral part of the converter

housing. The measurement reference

plane is at the Type "N" male output

connector.

Table 16: Specifications and Estimated Uncertainties for Low-Frequency TVC Services

Recommended

Frequencies

RF Voltage

Range

(V)

Estimated

Limits of Uncertainty*

(±%)

0.03, 0.1, 0.1 to 200 0.05

0.3, 1 MHz

3 and 10 MHz 0.1 to 200 0.1 30 MHz 0.1 to 200 0.2 100 MHz 0.1 to 200 1.0

* Rf-dc differences greater than ± 20 percent will not be reported. This normally limits the calibrations to 100 MHz and below.

Table 17: Specifications and Estimated Uncertainties for High-Frequency TVC Services

RF Voltage Estimated

Frequency Range Limits of Uncertainty*

(MHz) (V) (±%)

10 0.1 to 7.5 0.1 30 0.1 to 7.5 0.2

100, 200, 300, 400 0.1 to 7.5 1 500, 600, 700 0.1 to 7.5 1 900, 900, 1000 0.1 to 7.5 1

• Rf-dc differences greater than ±20 percent will not be reported.

139
53405S-53445S

Peak-to-Peak Detectors (534308-

53431S)

Measurements on peak-to-peak detectors are performed from 100 kHz

to 500 MHz and are referenced to the center of a GR 874 "T" connector. A 50-kHz ac reference signal is applied instead of dc. The services

available are specified in Table 18.

Table 18: Specifications and Estimated Uncertainties for Peak-to-Peak Detector Services

Applied RF Voltage Estimated Limits

Frequency for "0" Detector Output of Uncertainty

(MHz) (Vp-p) (%)

0.1, 0.3, 1.0 1.2 0.15

3, 10 1.2 0.20 30 1.2 0 30 50 1.2 0.60

100, 200, 300, 400, 500 1.2 1.10

RF Micropotentiometers

(53440S-53445S)

Radiofrequency micropotentiometers

are usually calibrated at their nominal

rated output voltages. Frequencies

suggested for a normal calibration are

5, 100, 300, 400, 500, 700, and 900

MHz. Special arrangements may be

made for calibrations up to 1000

MHz with reduced limits of uncertainty.

Radiofrequency micropotentiometers having resistive elements greater

than 10 milliohms in combination

with thermoelement housings between 5 and 100 mA, usually have rf- dc differences within ± 1 percent at 5 MHz. Since the rf-dc difference ap- proaches zero below 5 MHz, calibra- tions at 50 kHz and 5 MHz would

suffice to determine interpolated

points of interest between 50 kHz and

5 MHz, with no appreciable loss of

accuracy. Estimated uncertainties are shown in Table 19.

An rf-dc difference of about ± 5 percent at 1 MHz usually results from

a combination consisting of a 1 mil- liohm resistive element with a ther- moelement rated between 5 and 100

mA inclusive. Interpolation below 1 MHz is not recommended in this case.

Table 19: Specifications and Estimated Uncertainties for RF Micropotentiometer Calibrations

Any Frequency RF Voltage Estimated

within Band Range Limits of Uncertainty*

(MHz) (jiiV) (±%)

0.05 to 100 1 to 100,000 2

100 to 500 1 to 100,000 3 500 to 900 1 to 100,000 5

* For rf-dc differences greater than ±20 percent, the estimated limits of uncertainty are larger than those listed.

The rf-dc difference is defined as the percentage difference between

the rf and dc output voltages required

to produce the same thermocouple

output, with the resistive element

terminated in 50 ohms, e.g.,

rf-dc difference (%) = \^-^^\r^j x 100.

As a special service, rf micropotentiometers with rated output voltage

greater than 200 jxV can be cali- brated from 0.05 to 1000 MHz, with

reduced limits of uncertainty from

±0.2 percent to ±2 percent. This uncertainty is dependent on frequency,

output voltage level, and the rf-dc dif- ference vs. frequency response. For

further details, consult with the technical contact cited at the beginning of

this section.

140
53405S-53445S

References -RF-DC Voltage and

Current Converters (100 Hz-1 GHz)

NBS RF Voltage Comparator, L. D.

Driver, F. X. Ries, G. Rebuldela,

Natl. Bur. Stand. (U.S.), NBSIR

78-871 (Dec. 1978).

High-Frequency Microvolt Measurements, F. X. Ries and

G. Rebuldela, ISA Proc, 18, 1, 37.2.63, Instrum. Soc. of Amer.,

Res. Triangle Park, NC (Sept.

1963).

Thermal Voltage Converters for Accurate Voltage Measurements to 30 Megacycles Per Second, F. L. Hermach and E. S. Williams, Trans. AIEE, Pt. 1, Commun.

Elect., 72, 200 (July 1960).

Thermal Converters as AC-DC

Transfer Standards for Current

and Voltage Measurements at Audio Frequencies, F. L. Hermach,

J. Res. Natl. Bur. Stand. (U.S.),

48, 121 (1952).

Accurate Radio Frequency Microvoltages, M. C. Selby, Trans. AIEE, Pt. 1, Commun. Elect., 72,

158 (May 1953).

141
53500S-53540S

C Voltage Measurements

C.5 Data Converters

Technical Contacts:

T. Michael Barry A. Bell Souders Tel: 301/975-2419

Tel: 301/975-2406

Mailing Address: B162 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 53500S Special Data Converter Services, by Prearrangement

535 IOC A/D or D/A Converter, Linearity Errors at 1024

Points, 10-Bit Correction Coefficients, and Superposition Errors 53520C A/D or D/A Converter, Differential Linearity Errors at 2(N-1) Points (N = No. of Bits) 53530C A/D Converter, Equivalent RMS Input Noise

53540S A/D or D/A Converter, Offset and Gain Errors

Relative to U.S. Legal Volt

Data Converters (53500S-53540S)

NIST maintains a calibration service

for static testing of high-resolution

(12 to 18 bit) analog-to-digital (ADC)

and digital-to-analog (DAC) converters. Routine measurements, for which

calibration reports are issued, are made of the static parameters listed below. However, NIST has recently

developed the capability to measure

the dynamic response of ADC's to well-defined, programmable input

voltage steps characteristic of typical

input signals. These dynamic measurements can be made as a special

test. Until further analysis of systematic and random errors of the test procedure is completed and until additional operating experience is obtained, the customer will receive the

test results with appropriate error

analysis, but no calibration report will be issued. There is no standard data- converter terminology, but NIST uses

the following definitions of parameters to describe its calibration service: A. Linearity Error: The differ- ence between the actual and ideal

levels of the static input/output characteristic after corrections have been

made for offset and gain errors. B. Differential Linearity Error: The difference between the actual and the ideal separation between adjacent levels. C. Offset Error: The difference

between the actual and the ideal levels, measured at the most negative

level of the input/output characteristic. Due to practical considerations,

this definition is modified to the sec- ond most negative level (i.e., with the

least significant bit (LSB) on).

D. Gain Error: The difference

between actual and ideal levels, measured at the most positive level of the

input/output characteristic, after cor- rection for offset error. Again, in practice, a defining level is chosen

slightly below the one stated here. E. Equivalent RMS Input Noise:

The rms value of the effective inter- nal noise of an ADC, referred to its input terminals. In these definitions, the specified

levels for DAC's are taken to be the

discrete output levels, and for ADC's

the analog input levels are those at which the digital output transitions

between adjacent codes occur. In this latter case, the transition levels are defined by the upper digital code of

the transition in question.

The principal error parameters are

usually those of linearity and differential linearity. Nevertheless, gain and

offset errors may also be measured

when appropriate, and the equivalent rms input noise of ADC's can be

142
53500S-53540S

measured as well, provided it has ap- proximately a Gaussian distribution. Determination of monotonicity in DAC's and missing codes in ADC's is not generally performed since these

tests require excessive measurement

time for high-resolution converters. These characteristics can often be in- ferred, however, from the available

linearity data. Sensitivity of the vari- ous parameters to changes in temperature and power supply voltage, for example, is also not generally deter- mined.

Description of Static Tests: A. Linearity: For the linearity

test, all 1024 digital codeword combinations of the 10 most significant bits are measured. Errors contributed by

the remaining, less significant bits are generally insignificant, a premise

which is tested during the calibration process. The data are numerically

processed to determine the maximum,

minimum, and rms errors of the 1024

tested codes, and to determine, on a least-squares basis, individual correction coefficients for the 10 most sig- nificant bits. The residuals from the

computation of correction coefficients are a direct measure of the converter's superposition errors. These

are computed as well. B. Differential Linearity: Differential linearity errors are measured at 2(N-1) major codeword transitions, for an N-bit converter. C. Offset & Gain: In general, converter offset and gain measure- ments are not required, since it is common practice to provide adjustable trimmer circuits, which are

periodically set to suit individual sys- tem requirements. However, accurate

voltage measurements directly trace- able to legal standards can be pro- vided if required. Offset and gain

errors are measured directly by set- ting the test converter to the designated code and measuring the input

(or output) voltage by direct comparison with a transfer standard cali- brated by NIST.

D. RMS Input Noise: The equivalent rms input noise of ADC's can be measured either as an average

value over the entire full-scale range

of the converter, or as a function of

codeword, at 64 randomly selected

points. The measurement technique

relies upon the assumptions that the

noise has a Gaussian distribution and

that, at a given sampling rate, sucessive values are uncorrelated. The

validity of these assumptions is tested

prior to performing the measurements.

E. Specification for Test Converters: To be compatible with the

NIST data converter test set, test units must conform to the following

general specifications:

1. Nominal resolution from 12 to 18 bits,

2. Conversion rate of at least 10

kHz,

3. Binary coding format, including

binary sign-magnitude, offset bi- nary, 2's complement, I's complement, and complemented ver- sions of these,

4. TTL compatibility,

5. Voltage ranges of 0-5 V, ±5 V;

0-10 V, ± 10 V,

6. Maximum error, including offset and gain, not to exceed 500 ppm.

Systematic Uncertainties: The estimated limits of the systematic

uncertainties in measuring the various converter error parameters are summarized in Table 20 for a ± 10 V

range.

143
53500S-53540S

Table 20: Specifications and Estimated Uncertainties for Data Converter Calibrations

Parameter

Estimated Systematic Uncertainty

DAC's ADC's

Linearity Error

Differential Linearity Error

Offset Error'"' Gain Error*"' RMS Input

Noise*^'

2.7 ppm +0.04LSB

3.2 ppm +0.04LSB

3 ppm

6 ppm

4.7 ppm +0.16 LSB

5.2 ppm +0.16 LSB

3 ppm +0.07 LSB

6 ppm +0.13 LSB

-100%; +(20% + 10

|jlV) Noise introduced by the Test Set is approximately 30 nV/(Hz)"^in a 1-MHz bandwidth

Measured upon special request only, if no adjustable trimmers are provided for these parameters.

Since the effective bandwidth of the test converter is gersrally un- known, the noise contribution from the test set cannot be determined.

Therefore, only an upper limit can be accurately placed on the noise measurements.

Random errors of the measurement

process necessarily include random

variations in the test converter and

are, therefore, individually evaluated

for each test. Nevertheless, measure- ments on very stable (check standard)

converters indicate the random errors contributed by the test set itself are

substantially less than the respective

systematic uncertainties listed in the

table. Figure 10 shows the estimated

systematic uncertainty of the NIST

data converter test system for resolutions from 12 to 18 bits. Dynamic Tests ofADC's:

Dynamic errors in ADC's are defined

as any deviations from the static transfer characteristic resulting from

prior exercise (i.e., previous changes

in input). The test converter is exer- cised with stepped input changes typi- cal of the conditions of actual use. The dynamic errors are measured in terms of the changes in the test converter's code transition levels result- ing from prior exercise. A more

complete description of the dynamic

testing now provided for ADC's on a

Special Test basis is provided in Souders et al., "An Automated Test

Set for the Dynamic Characterization

of A/D Converters" (see references).

Figure 10. Uncertainty for NIST Data Converter Test System for Resolutions from 12-18 Bits

10"

10'

Integral Linearity Error

Differential Linearity Error

12 13 14 15 16

Resolution in Bits

17 18

Preparation of Test Boards:

In general, the customer is responsible for mounting the integrated cir- cuit, hybrid, or modular test converters on suitable test boards, and

for providing all required trimmer cir- cuits, voltage references, input or out- put amplifiers, recommended power

supply decoupling capacitors, and

connectors for interfacing to the in- put/output lines. Fully self-contained converters need only be fitted with

the necessary interfacing connectors.

In so doing, the customer gains significant performance advantages while

at the same time saving the additional

fee that would otherwise be charged

by NIST for performing this service. High-performance converters are

often susceptible to small changes

144
53500S-53540S

in grounding, routing of dynamic sig- nal lines, capacitive loading, etc. Particularly with ADC's, signal

dynamics are quite important, even

for static testing, because the converter itself always operates at high

speeds. When mounted by the cus- tomer, the test converter and its sup- port circuitry can be laid out to simulate more closely the way it will be used, according to the specific

manufacturer's recommendations.

Therefore, the test results should more closely describe the converter's

in situ performance. Detailed type

and wiring requirements for the inter- facing connectors are available upon

request.

References — Data Converters

An Automated Test Set for the Dynamic Characterization of A/D

Converters, T. M. Souders, D. R.

Flach, and T. C. Wong, IEEE

Trans. Instrum. Meas., IM-32,

No. 1, 180 (Mar. 1983).

A Calibration Service for Analog-toDigital and Digital-to-Analog Converters, T. M. Souders, D. R.

Flach, and B. A. Bell, Natl. Bur.

Stand. (U.S.), Tech. Note 1145

(July 1981). (Provides a complete

description of the calibration service.)

A Technique for Measuring the

Equivalent RMS Input Noise of AJ

D Converters, T. M. Souders and J. A. Lechner, IEEE Trans. Instrum. Meas., IM-29, No. 4, 251 (Dec.

1980).

A 20-Bit -I- Sign Relay Switched

D/A Converter, T. M. Souders and

D. R. Flach, Natl. Bur. Stand.

(U.S.), Tech. Note 1105 (Oct.

1979). (Describes the reference

standard used in the calibration

service.)

A High-Speed Low-Noise 18-Bit Digital-to-Analog Converter, H. K. Schoenwetter, IEEE Trans. In- strum. Meas., IM-27, No. 4, 413

(Dec. 1978).

145
54110S-54131C

D Precision Ratio Measurements

D.1 Inductive Dividers

Technical Contacts:

Norman B. Belecki

Tel: 301/975-4223

Denise B. Prather

Administrative and Logistics

Tel: 301/975-4221

Mailing Address: B146 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 2C899-0001

Test No. Items

541 lOS Special Ratio Measurements and Tests of Inductive Voltage Dividers, by Prearrangement

54120C Inductive Voltage Dividers — (Single Frequency,

Voltage To Be Specified, Each Setting of 3 Most

Significant Dials)

54121C Additional Frequency Points 54130C Inductive Voltage Dividers — (Single Frequency,

Voltage To Be Specified, Each Setting of Most

Significant Dial Only)

54131C Additional Frequency Points

Special Ratio Measurements and

Tests of Inductive Voltage Dividers,

by Prearrangement (541 lOS)

This service category provides for the

measurement and/or evaluation of

prototype ratio devices and inductive

voltage dividers based on new principles, and for unique ratio measure- ments at the highest accuracy levels, such as the determination of the ratios of Hamon resistance transfer devices or Silsbee-type voltage ratio standards. Such measurements are undertaken at the discretion of NIST

technical staff and only when the

need for them can be clearly demonstrated.

Inductive Voltage Dividers

(54120C-54131C)

Inductive voltage dividers (decade

transformer dividers) are accepted for calibration only at 50, 60, 100, 120,

400, 1000, 5000, and 10,000 Hz. The

most significant dial only can be cali- brated at 15 and 20 kHz.

Calibration voltages may be specified up to 100 V or the manufacturer's specified limit, whichever is lower. The largest contribution to in- stability in undamaged inductive

voltage dividers is wear or dirt in the

decade switches. Variable contact re- sistance in these switches sometimes

affects the stability of voltage-ratio

measurements to a significant extent but is most evident by its effect on

the phase angle. When a decade in- ductive voltage divider exhibits large

changes in phase angle for repeated

measurements after the switches have

been disturbed, the divider should no

longer be considered satisfactory for use as a voltage-ratio reference stan- dard. Inductive voltage dividers that use pushbutton switching or incorporate a resistive divider as a fine adjustment usually are not accepted for

calibration. Corrections to the separate decades

of an inductive divider, in general,

cannot be simply combined. However,

the correction to a step setting of one

of the higher decades usually is independent of the setting of the lower

decades. The effects of stray

impedances must be corrected by

connecting the case to the divider at one point, and unless otherwise specified, the case will be connected to one of the "common" terminals, typically marked "GRD," "Case GND,"

or "Case GRD." Decade inductive

voltage dividers are calibrated at NIST at room temperature (22 to 24 °C) by comparison with a twostage, three-decade transformer of

known ratios.

146
541105-541 31

C

References— Inductive Dividers

American National Standard for Decade Transformer Dividers

(Voltage Type), ANSI CIOO,

1-1972 Amer. Natl. Stand. Inst., New York, NY (Jan. 1972).

Instructions for the Use of the NBS

Reference Inductive Divider,

Wilbur C. Sze, Natl. Bur. Stand.

(U.S.), NBSIR, unpublished (1970).

(Available from NIST.)

Two-Stage, Guarded Inductive

Voltage Divider for Use at 100

kHz, D. H. Hamon and T. L. Zaf,

ISA Transactions, 9, 3, Instrum.

Soc. of Amer., Res. Triangle Park,

NC (1970).

Comparator for Calibration of Inductive Voltage Dividers from 1 to 10

kHz, W. C. Sze, ISA Transactions,

6, 4, Instrum. Soc. of America, Res,

Triangle Park, NC (1967).

147
54210C-54214S

D Precision Ratio Measurements

D.2 Resistive Dividers

Technical Contacts:

Martin Misakian Richard J. G«raid J. (DC Measurements) Van Brunt Fitzpatrick

Tel: 301/975-2426 (60-Hz Mea- (Pulsed Measurements) surements)

Tel: 301/975-2425 Tel: 301/975-2737

Mailing Address: B344 Metrology, National Institute of

Standarcis and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

For 54210C-54211S:

[Attn: M. Misakian, Bldg. 220, Room B351]

For 54212C-54213S:

[Attn: R. J. Van Brunt, Bldg. 202, Room 167]

For 54214S:

[Attn: G. J. Fitzpatrick, Bldg. 202, Room 106]

Test No. Items 54210C Resistor and Resistive Dividers, Total Resistance or Voltage Ratio, Two Direct Voltage Levels between

10 kV and 150 kV

54211S Special Tests of Resistor and Resistive Dividers at Direct Voltage Levels, by Prearrangement

54212C Resistor and Resistive Dividers at 60 Hz, Voltage

Ratio and Phase Angle, between 10 kV and

100 kV rms

54213S Special Tests of Resistor and Resistive Dividers at 60 Hz, by Prearrangement

54214S Special Tests of Resistor and Resistive Dividers Under Pulsed High-Voltage Conditions, by

Prearrangement

Resistor and Resistive Dividers, DC

Measurements (54210C-54211S)

A calibration service is maintained at NIST to determine the do voltage ratio of resistive dividers. The routine

calibration service is available for applied voltages from 10 kV to 150 kV.

The calibrations are performed with a measurement system which has an

uncertainty of ±0.01 percent of the

voltage ratio. To assure adequate sensitivity at the lowest applied voltage

levels, calibrations are performed routinely only on dividers with ratios of

100,000:1 or smaller. The routine caHbration service is also restricted to di- viders with nominal ratios of

100,000:1, 10,000:1, or 1,000:1.

Resistive dividers are acceptable

for calibration only if they are nearly corona free at the rated operating

voltage and are designed to have

small temperature and voltage coefficients. Specifically, a device is not

generally suitable for calibration by

NIST if these coefficients produce a change in the ratio of ±0.1 percent

over the normal range of operating

voltages. At a given voltage, dividers

should not exhibit instabilities in their

ratio value in excess of 0.005 percent.

NIST staff can provide some assis- tance in the identification of other

calibration laboratories capable of

certifying the response of less accurate dividers.

Resistor and Resistive Dividers, 60- Hz Measurements (54212C-54213S)

Resistive dividers of sufficient quality

to be considered as transfer standards

are calibrated at 60 Hz for applied

voltages between 10 kV and 100 kV

rms. High-voltage dividers may per- form satisfactorily as standards under

dc voltages but do not perform well enough to be considered as standards

when excited by 60-Hz voltages. The

design of an ac divider requires special features, beyond those of a dc di- vider. In particular, ac dividers

designed to be used as transfer stan- dards may have to be equipped with

external shielding to minimize the ef- fects of capacitive coupling to sur- rounding objects.

148
54210C-54214S

If the device is not properly

shielded, the effects of proximity to surrounding objects and pickup from

high-voltage conductors can introduce

large uncertainties into the measured

value of the divider ratio. In such

cases, the measurement of the ratio for one configuration would not necessarily be valid for another configuration. Consequently, a meaningful

calibration of the device is difficult or

impossible.

Therefore, we recommend that the

following two preliminary proximity

tests be performed before an ac di- vider is submitted for test to deter- mine the suitability of the device as a

transfer standard. Place the divider

about 2.0 m from a vertical ground

plane as measured from the center of

the device. Energize the divider to some safe high-voltage level and measure the divider ratio. Repeat the

measurement with the same applied

high voltage but with the vertical ground plane (or divider) moved into a position 1.2 m from the center of

the divider. If the measured divider

ratio changes by 0.1 percent or more,

the device has excessive capacitive

coupling and is not suitable as a

transfer standard.

To test for pickup, remove the

high-voltage connection to the top of

the divider and then connect the top

of the divider to ground with a thin

wire. Measure the output voltage of

the divider under these conditions

both with and without the highvoltage source energized. If the re- sulting change in the output voltage

exceeds 0.1 percent of the expected

output voltage when the high voltage

is connected to the divider, then

again there is excessive coupling indi- cating that the device is not suitable

as a transfer standard.

High-voltage ac dividers sent to NIST are first subjected to tests like those described above before any

measurements are attempted. If such

tests show variations in the measured

ratio of more than 0.1 percent for

either proximity or pickup, then no

further tests will be performed and

the device will be returned. Prior to performing any measurements, di- viders sent to NIST will also be subjected to a breakdown test at the

highest voltage for which measure- ments are requested. The customer

will be charged for the cost of these

tests. NIST calibration of voltage trans- formers at 60 Hz is generally more

accurate than its calibration of di- viders at the same frequency. Therefore, customers having a requirement

for a calibrated divider may find it advantageous to use a voltage trans- former as the transfer standard and

to use that transformer to calibrate

the divider in their own facilities. Routine tests are carried out for voltages between 10 kV and 100 kV

rms and are performed with a measurement system having an uncertainty of 0.05 percent in the

determination of the ratio and ±0.5

milliradian in the determination of

the phase angle.

Resistor and Resistive Dividers,

Pulsed High-Voltage Conditions

(54214S)

Resistive divider ratios are also deter- mined under pulsed high-voltage conditions. All pulsed measurements are by prearrangement. Determinations

employ special-design pulse dividers

and calibrated Kerr cells as reference

standards. A variety of pulses may be

applied to simulate the conditions un- der which the divider will be used.

Calibrations are made at selected

voltage intervals from 20 kV to 300

kV as requested and up to 500 kV

with certain pulse shapes. The typical

uncertainty is ± 3 percent of the

voltage ratio although smaller uncertainties can occasionally be reported

as a special test.

Shipping:

Dividers can be hand-carried or shipped to NIST. Shipped dividers

should be packaged in sturdy reusable

149
54210C-54214S

containers. The design of many highvoltage dividers makes them vulnerable to shear-type forces, so provisions

should be made to minimize the

likelihood of damage due to such

forces when the device is in the shipping container.

References — Resistive Dividers

High-Voltage Divider and Resistor

Calibrations, M. Misakian, Natl. Bur. Stand. (U.S.), Tech. Note

1215 (July 1985).

Evaluation of a Multimegavolt Impulse Measurement System, R. E. Hebner, D. L. Hillhouse, and R. A.

Bullock, Natl. Bur. Stand. (U.S.),

NBSIR 77-1933 (Nov. 1979).

Calibration of High-Voltage Pulse

Measurement Systems Based on

the Kerr Effect, Natl. Bur. Stand.

(U.S.), NBSIR 77-1317 (Sept.

1977).

Special Shielded Resistor for HighVoltage Measurements, J. H. Park,

J. Res. Natl. Bur. Stand. (U.S.),

66C, No. 1, 19 (Jan.-Mar. 1962).

150

1
543 IDS;-54311S

D Precision Ratio Measurements

D.3 Capacitive Dividers

Technical Contacts:

Robert E. Richard J. Gerald J. Hebner, Jr. Van Brunt Fitzpatrick

Tel: 301/975-2403 (60-Hz Mea- (Pulsed Measurements) surements)

301/97S-2425 Tel: 301/975-2737

I Mailing Address: B344 Metrology, National Institute of

i Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithers-

; burg, MD 20899-0001

For 54310S:

[Attn: R. J. Van Brunt, Bldg. 202, Room 167]

For 54311S:

' [Attn: G. J. Fitzpatrick, Bldg. 202, Room 106]

Test No. Items 54310S Special Tests of Capacitive Dividers at 60-Hz,

by Prearrangement

54311S Special Tests of Capacitive Dividers Under Pulsed High-Voltage Conditions, by Prearrangement

Capacitive Dividers, 60-Hz Measurements (54310S)

Determinations of capacitive divider

ratios at 60-Hz ac employ the same

equipment used for the calibration of

ac resistive dividers (see 54212C).

The same limitations pertain to shielding (proximity and pickup ef- fects). The NIST measurement sys- tem imposes a negligible burden on

the divider if its output voltage is 100

volts or less. Otherwise, the burden is equivalent to a 1000-picofarad capacitor.

Capacitive Dividers, Pulsed

High-Voltage Conditions (543118)

Determinations of capacitive divider

ratios under high-voltage pulse conditions employ special-design pulse di- viders and calibrated Kerr cells as reference standards. A variety of

pulses may be applied to simulate the

conditions under which the divider

will be used. Calibrations are made at selected voltage intervals from 20 kV

to 300 kV as requested and up to 500

kV with certain pulse shapes. The

typical uncertainty is ±3 percent of

the voltage ratio although smaller uncertainties occasionally may be negotiated.

References — Capacitive Dividers

High-Voltage Divider and Resistor

Calibrations, M. Misakian, Natl. Bur. Stand. (U.S.), Tech. Note

1215 (July 1985).

Evaluation of a Multimegavolt Impulse Measurement System, R. E. Hebner, D. L. Hillhouse, and R.A.

Bullock, Natl. Bur. Stand. (U.S.),

NBSIR 79-1933 (Nov. 1979).

Calibration of High-Voltage Pulse

Measurement Systems Based on

the Kerr Effect, Natl. Bur. Stand.

(U.S.), NBSIR 77-1317 (Sept.

1977).

Special Shielded Resistor for HighVoltage Measurements, J. H. Park,

J. Res. Natl. Bur. Stand. (U.S.),

66C, No. 1, 19 (Jan.-Mar. 1962).

151
54410S

D. Precision Ratio Measurements

D.4 Mixed Dividers

Technical Contact:

Gerald J. Fitzpatrick

Tel: 301/975-2737

Mailing Address: B344 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 544 lOS Pulse Voltage Measuring Systems,

Including Kerr Cells

References — Mixed Dividers

Evaluation of a Multimegavolt Impulse Measurement System, R. E. Hebner, D. L. Hillhouse, and R. A.

Bullock, Natl. Bur. Stand. (U.S.),

NBSIR 79-1933 (Nov. 1979).

Calibration of High-Voltage Pulse

Measurement Systems Based on

the Kerr Effect, Natl. Bur. Stand.

(U.S.), NBSIR 77-1317 (Sept.

1977).

Special Shielded Resistor for HighVoltage Measurements, J. H. Park,

J. Res. Natl. Bur. Stand. (U.S.),

66C, No. 1, 19 (Jan.-Mar. 1962).

Mixed Dividers (54410S)

A mixed divider is one constructed of

resistors and capacitors. Ratios of

mixed-voltage dividers are determined

under pulsed, high-voltage transient

conditions. Determinations employ

specially-designed pulse voltage di- viders and calibrated Kerr cells as reference standards. A variety of

pulse waveshapes may be applied to simulate the conditions under which

the divider will be used. Calibrations

are made at selected voltage intervals from 20 kV to 300 kV as requested

and up to 500 kV with certain pulse

shapes. The typical uncertainty is ±3

percent of the voltage ratio although

smaller uncertainties can occasionally

be reported as a special test.

152
I 54510O54600S

D Precision Ratio Measurements

D.5 Voltage and Current Transformers

Technical Contacts:

James K. Thomas L. Nelson

OlthofT (Current Transformers)

(Voltage Tel: 301/975-2416 Transformers)

Tel: 301/975-2431

Mailing Address: B344 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

For 54510C-54513C:

[Attn: J. K. Olthoff, Bldg. 202, Room 167]

For 54520C-54522C:

[Attn: T. L. Nelson, Bldg. 220, Room B165]

Test No. Items 54510C Voltage Transformer, Ratio & Phase Angle, at 60 Hz

on 1 Range, 1 Secondary Voltage, 1 Burden

Primary VTMs =S 150 kV

54511C Same as 54510C, Additional Similar Transformer at Same Time

54512C Same as 54510C and 54511C, Additional Burden or Range

54513C Same as 54510C-54512C, at Each Additional

Secondary Voltage

54520C Current Transformer, Ratio & Phase Angle, 1 Range

at 1 Frequency and 1 Burden, Secondary Currents

0.5, 1, 2, 3, 4, 5 A, Primary Current Not Over 12,000 A

54521C Current Transformer, Ratio & Phase, 1 Secondary

Current, Additional Combination of Range,

Frequency, and Burden, Primary Current Not

Over 12,000 A

54522C Current Transformer, Ratio & Phase at Each

Additional Secondary Current, Same Combination

of Range, Frequency, and Burden as 54520C

or 54521C

54600S Special Tests of Dividers and Transformers, by

Prearrangement

Voltage Transformers

(54510C-54513C)

NIST provides routine services for the measurement of complex voltage

ratios (magnitude and phase angle) of

transformers for primary voltages up

to 150 kV and for secondary voltages

above 50 V, subject to some constraints as to the maximum physical

size of the device. Results of these

routine tests are reported with an uncertainty of ±0.03 percent for ratio and 0.3 mrad (1 mrad — 3.438 min)

for phase angle. If the test conditions

and the device under test warrant,

special tests with smaller uncertainties can be performed. These special

tests may require an extra fee. The customer must specify the sec- ondary voltage and the secondary

burden for each transformer or for each range of a multirange trans- former. Ambiguity can be avoided if the impedance and power factor, or

the resistance and reactance, are

specified rather than the volt-ampere

rating of each burden. The customer

should note that the NIST calibration

system represents a minimum burden

of 1000 pF for routine calibrations. The customer should give some care

to the specification of a burden

recognizing that the use of the trans- former with a burden different from

that used in the calibration can result

in significant error. Calibrations of voltage transformers

are performed routinely only at 60

Hz. Measurements are made with one

side of both the primary and sec- ondary windings connected to ground.

NIST does have some capability to perform measurements at voltages,

frequencies, and burdens outside of

the ranges described above. Calibrations can occasionally be provided at these nonroutine test points as a special test for an increased fee.

153
Current Transformers

(54520C-54522C)

Normally NIST calibrates only cur- rent transformers of high quality for use as reference standards. The NIST

equipment is designed to test current transformers with a rated secondary

current of 5 A, with test points cho- sen to be one or more of the follow- ing values: 0.5, 1, 2, 3, 4, 5 A.

Routine tests are carried out at 50,

60, and 400 Hz. For measurements at 50 or 60 Hz, the results are generally

reported with an uncertainty of

±0.01 percent in ratio and ±0.1

mrad in phase angle. For measure- ments at 400 Hz, the reported uncertainty is ±0.03 percent in ratio and

±0.3 mrad in phase angle.

The customer must specif (he test frequency, the secondary currents,

and the secondary burdens for each

transformer or for each range of a multirange transformer. Current

transformers should be tested with

burdens equivalent to those which are imposed when the device is used as a transfer standard. Routine calibration

using the burdens specified in the

American National Standards Insti- tute (ANSI) Standard C-57.13 is not recommended unless these burdens

are subsequently used in the cus- tomer's factory or laboratory. Large

errors can result if the values of ratio and phase angle obtained with an ANSI recommended burden are used

for the transformer when it is con- nected to a different burden.

Preferably the burden should be

specified in terms of the measured

resistance and inductance. These val- ues should include the effects of the

leads used to make a connection to the transformer secondary. An alter- native, which is sometimes feasible, is to submit the transformer together

with its normal leads and connected

burden for calibration as a unit. If neither of the above are possible, the

burden may be stated in terms of the

voltampere product and the power

factor of the secondary circuit at the

test frequency. For reference, it

should be noted that the test equipment regularly used at NIST represents a minimum test burden of about

0.03 ohms with a inductance of about

10 ^JLH. Because of contact resistance and

current rectification, loose or dirty

primary and secondary terminations

may affect the measurement results. These surfaces should be tight and

clean when the transformer is shipped to NIST to minimize this source of error. Unless otherwise specified, current transformers are demagnetized prior

to calibration. If it is desired to have

a transformer tested as submitted

(without demagnetization), this re- quirement should be stated on the

purchase order and NIST staff should

be informed by telephone before the

transformer is shipped.

Many current transformers are not designed to be used as transfer stan- dards, and most of these do not re- quire calibration at NIST. NIST staff can provide some assistance in the as- sessment of the appropriateness of

the device for NIST calibration and

in the identification of alternative cal- ibration sources. If NIST is required

to perform laboratory measurements

to determine whether or not a partic- ular device can be calibrated, a charge for the cost of these

measurements will be made.

Special Tests of Dividers and

Transformers (54600S)

The Electricity Division maintains an

active program of research and devel- opment in the area of electrical measurements at high-voltage levels. For

this reason, NIST often is able to provide measurement support for high-voltage devices other than those

listed above in this section. Special

tests will generally be conducted by

NIST, if the following criteria are met:A. The requested tests are fully

developed and documented.

154
545 IOC-;-54600S

B. There is a significant technical or economic justification for traceability of the test on the item to national

standards.

C. There has not been a routine or recurrent need for the test.

References— Voltage and Current

Transformers

A Calibration Service for Voltage

Transformers and High-Voltage

Capacitors, W. E. Anderson, Natl. Bur. Stand (U.S.), Spec. Publ. 250-

33 (June 1988).

An Electronic Ratio Error Set for Current Transformer Calibrations, R. L. Kahler, IEEE Trans. Instrum. Meas., IM-28, No. 2, 162 (June

1979).

A Wide-Range High-Voltage Capacitance Bridge with One-ppm Accuracy, O. Petersons and W. E. Anderson, IEEE Trans. Instrum. Meas., IM-24, No. 4, 336 (Dec.

1975).

Wide-Band Two-Stage Current Trans- formers of High Accuracy, T. M.

Souders, IEEE Trans. Instrum. Meas., IM-21, No. 4, 340 (Nov.

1972).

A Wide-Range Current Comparator

System for Calibrating Current

Transformers, T. M. Souders,

IEEE Trans. Power Appar. Syst.

PAS-90 No. 1, 318 (Jan.-Feb.

1971).

155
55110S-55141C

£ Phase Measurements

E.1 Phase Meters and Standards

Technical Contacts:

Raymond S. Turgel

Tel: 301/975-2420

Barry A. Bell

Tel: 301/975-2419 Mark E. ParkerTel: 301/975-2413

Mailing Address: B162 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Test No. Items 55110S Special Tests of Phase Standards and Related

Instruments, by Prearrangement

55120C Phase Meters — One Combination of Input Voltages

(0.5 V to 100 V rms) at one Frequency (2 Hz to 50 kHz) -the Input Voltage Ratio Shall Not

Exceed 10 55121C Phase Meters — Each Additional Combination of Input Voltages (0.5 V to 100 V rms) at the Same or at a Different Frequency (2 Hz to 50 kHz) — the Input

Voltage Ratio Shall Not Exceed 10 55130C Phase Meters — One Combination of One Input

Voltage (0.5 V to 120 V rms) and One Input Current

(1 to 5 A rms) at One Frequency (2 Hz to 5 kHz)

55131C Phase Meters — Each Additional Combination of One

Input Voltage (0.5 V to 120 V rms) and One Input Current (1 to 5 A rms)

55140C Phase Meters-One Input Voltage (0.5 V to 120 V

rms) and Another Input Voltage (0.5 V to 100 V rms)

at One Frequency (2 Hz to 5 kHz)

55141C Phase Meters — Each Additional Combination of One

Input Voltage (0.5 V to 120 V rms) and Another

Input Voltage (0.5 V to 100 V rms) at the Same or at a Different Frequency (2 Hz to 5 kHz)

arrangements for these tests should

be discussed with NIST; prior ar- rangements are essential.

Phase Meters (55120C-55141C)

NIST has a capability for characterizing audio frequency phase meters

over a frequency range of 2 Hz to 50

kHz. The standard used is a microcomputer-based system that synthesizes two sinusoidal voltages by means

of digital techniques. The two signals are displaced relative to one another

by a precisely known phase angle.

Phase angles can be set with a resolution of 0.002 degree up to 5 kHz and

0.005 degree above 5 kHz. The amplitude of the two output signals can be

varied independently from 0.5 volt to 100 volts rms. At power frequencies, one of the signals can be a current from 0.5 to 5 amperes. The uncertainty in setting the standard is less than ±0.01 degree below 5 kHz and

increases to ±0.04 degree at 50 kHz

if the two output signals have the same amplitude. For unequal outputs,

this uncertainty increases to ±0.015

degree and ± 0.090 degree respectively, if the amplitude ratio is less than 10:1. Although the accuracy of the phase

angle standard does not rely on the

stability of the frequency, the generated output, which can be varied in steps of 1 Hz, is locked to a crystalcontrolled frequency synthesizer.

Figure 11 shows a plot of the total estimated uncertainty of the NIST

Phase Angle Calibration Standard as a function of frequency for two limit- ing amplitude ratios.

Special Tests of Phase Standards

and Related Instruments,

by Prearrangement (551 lOS)

NIST will perform special-test phase

angle measurements on phase angle

generators, quadrature detectors, and

phase bridge-networks. Restrictions

apply, and technical limitations and

156
55110S-55141C

Figure 1 1. Estimated Total Uncertainties of tlie NIST

Pliase Angle Calibration Standard

0.100

0.080

Amplitude Ratio 0.060 10:1 \/ ,

0.040

0.020

0.000 1 II 1 0.002 5 10 15 30 50

Output Frequency (KHz)

Special requirements for this service are as follows: A. The voltage inputs of phase

meter to be tested must have

impedances such that the current is limited to a few milliamperes at any

applied voltage requested. Current in- puts must have impedances low

enough so that the compliance

voltage does not exceed 2 volts. B. NIST will test the instrument

in the as-received condition, without

making any zero or gain adjustments.

C. In some cases, the response of

phase meters involves significant time

constants; in these cases, readings will be taken 30 seconds after the setting

of the standard.

D. For given voltage and fre- quency settings, at least three readings will be taken at each specified

phase angle. The order of readings

will be randomized.

E. The experimental data are fit- ted to a mathematical model from

which the phase meter response can be predicted. From the closeness of

fit to the model, it can be determined

whether observed deviations from the

predicted values are significant. F. Each phase meter will be operated under power for at least 2 hours

before test data are taken.

G. Meters that are not in operating condition upon receipt at NIST

will be returned to the owner without

repairs.

References — Phase Meters

NBS Measurement Services: Phase

Angle Calibration Services, R. S. Turgel, J. M. Mulrow, and D. F. Vecchia, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-26 (May 1988).

Phase Meter Calibrations at NBS,

R. S. Turgel, J. Res. Natl. Bur.

Stand. (U.S.), 93, No. 1, 53-59 (Jan.

1988).

Precision Calibration of Phase Meters, R. S. Turgel and D. F. Vecchia, IEEE Trans. Instrum. Meas., IM-36, No. 4, 915-922 (Dec.

1987).

NBS 50-kHz Phase Angle Calibration

Standard, R. S. Turgel, Natl. Bur.

Stand. (U.S.), Tech. Note 1220

(Apr. 1986).

A Wideband Transconductance Amplifier for Current Calibrations,

O. B. Laug, IEEE Trans. Instrum. Meas., IM-34, No. 4, 639-643 (Dec.

1985).

A Precision Phase Angle Calibration

Standard for Frequencies Up to 50

kHz, R. S. Turgel, IEEE Trans. In- strum. Meas., IM-34, No. 4, 509-

516 (Dec. 1985).

NBS Phase Angle Calibration Standard, R. S. Turgel, N. M. Oldham,

G. N. Stenbakken, and T. H.

Kibalo, Natl. Bur. Stand. (U.S.),

Tech. Note 1144 (July 1981).

A High-Performance Phase-Sensitive

Detector, L. A. Marzetta, IEEE

Trans. Instrum. Meas., IM-27, No.

4, 460-464 (Dec. 1978).

High-Precision Audio-Frequency

Phase Calibration Standard, R. S. Turgel and N. M. Oldham, IEEE

Trans. Instrum. Meas., IM-27, No.

4, 460-464 (Dec. 1978).

157
55210C-55230S

E Phase Angle Measurements and

Air Navigation Aids

E.2 Very-High-Frequency Omnidirectional

Range (VOR) Measurements

Technical Contacts:

Neil T. Larsen David H. Kathy Hiilen

Tel: 303/497-3711 Russell Administrative

Tel: 303/497-3148 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of Stan- dards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 55210C VOR Bearing-Angle Indicators, 12 Bearing Angles

Over the Range 0 to 330 Degrees

5521 IC Calibration of VOR Bearing-Angle Indicator at Each

Additional Angle

55220C VOR Generators, 12 Bearing-Angle Equivalent

Signals Over the Range 0 to 330 Degrees

55221 C Calibration of VOR Generator at Each Additional

Angle

55230S Special VOR Tests

VOR Measurements — General

Information

The NIST calibration services for VOR air navigation signals are described in detail in VOR Calibration

Service, NBS Technical Note 1069

(see references).

Two services are offered to support

the calibration of VOR (Very-highfrequency Omnidirectional Range)

instruments. NIST has designed and

built a standard VOR audio generator, used to calibrate unknown VOR

bearing-angle indicators, and a stan- dard VOR bearing-angle indicator,

used to calibrate unknown audio

generators. Direct generation or

measurement of standard VOR rf sig- nals are not a part of the service. Quality control of the NIST stan- dards is accomplished by using each

to measure the other. As a result of

these measurements, the uncertainty

of a calibration of either a generator

or a bearing-angle indicator is given

by the following statement, which is part of the calibration report:

"The assigned values of VOR bearing angles are the nominal bearings

from 0 to 360 degrees in increments

of 0.01 degrees. The overall uncertainty of these values has been esti- mated from test data at bearings from

0 degrees to 360 degrees at 30-degree

increments. Thus, each of the nominal bearings has been assigned a provisional overall uncertainty of

±0.0017 degrees, based on estimated

bounds of 0.00065 degrees on the sys- tematic error and a computed stan- dard error of 0.00105 degrees."

VOR Bearing-Angle Indicators

(55210C and 55211C)

An unknown bearing-angle indicator

is calibrated by connecting its input to the output of the NIST standard generator. The generator provides a composite audio signal that is the sum of

two signals, each 1 volt rms ( ± I per- cent) in amplitude. The first signal is a 30-Hz sinusoid and represents the

variable phase signal recovered from

the VHF carrier. The second is the

frequency-modulated 9960-Hz subcarrier. NIST will calibrate at any set of

12 bearing angles specified by the

customer (if not specified, at 30- degree intervals over the inclusive

range 0 to 330 degrees).

158
552 lOC-:-55230S

VOR Generator (55220C and 55221C)

Only certain commercial VOR generators are suitable for calibration. They should provide a composite au- dio signal of nominally 1 volt rms, per

tone. They must have a short-term

phase jitter of less than 10 nsec. The

modulation index for the 9960-Hz

subcarrier must be equal to 16 ± 1 percent. Most commercial generators

do not meet these requirements and

can best be calibrated by submitting a bearing-angle indicator for calibration

instead. This can then be used to transfer the NIST calibration to the

unknown generator with some loss of

accuracy. An uncertainty statement

for this transfer has not been developed due to lack of history. NIST will calibrate at any set of 12 bearing-angle equivalent signals corresponding

to bearing-angles specified by the cus- tomer (if not specified, at 30-degree

intervals over the inclusive range 0 to 330 degrees).

Special VOR Tests (55230S)

The NIST standard bearing-angle

indicator lends itself to the measure- ment of audio frequency periodic

waveforms through the use of sampling techniques and time series analysis. It has been used for the accurate measurement of phase angles between two sinusoids. Special tests of

this nature may be provided by prear- rangement. The uncertainty depends

upon the frequency; at 30 Hz it is about 0.0006 degrees (3 standard deviations).

References— VOR Measurements

VOR Calibration Services, N. T. Larsen, D. F. Vecchia, and G. R.

Sugar, Natl. Bur. Stand. (U.S.),

Tech. Note 1069 (April 1985).

Fourier Transformation of the Nonlinear VOR Model to Approximate

Linear Form, D. F. Vecchia, Natl. Bur. Stand. (U.S.), Tech. Note

1021 (June 1980).

159
56110S-56210M

F Power and Energy Measurements,

Low-Frequency

Technical Contacts:

Andrew J. Thomas L. Secula Nelson

Tel: 301/975-2416 Tel: 301/975-2427

Mailing Address: B344 Metrology, National Institute of

Standards and Technology, Gaithersburg, MD 20899-0001

Shipping Address: National Institute of Standards and

Technology, 1-270 at Quince Orchard Road, Gaithersburg, MD 20899-0001

[Attn: A. J. Secula, Bldg. 220, Room B165]

Test No. Items 56110S Special Tests of AC-DC Wattmeters, by

Prearrangement

56200C Watt, Watthour Var or Varhour Meter, Initial Two

Determinations of Percentage Registration of Same Meter at 60 Hz

56201C Each Additional Determination of Percentage

Registration of Same Meter at 50/60 Hz

56202C Initial Two Determinations of One or Two

Meters Run Simultaneously with the First (56200C)

56210M Measurement Assurance Program for Watthour Meters

Power and Energy Measurements,

Low-Frequency (56110S-56210M)

Only standard electronic-type watt,

watthour, var and varhour meters are accepted for test. Rotating types are no longer accepted except by special

arrangement. If necessary, the meters

should be cleaned or adjusted by the

customer before they are shipped to NIST. NIST does not adjust meters

and does not knowingly begin tests of

faulty meters.

The test conditions must be specified by the customer. These include

the current and voltage ranges to be

tested, the frequency, the applied

voltages, the applied currents, and

the power factors. Values of these

parameters which are available for routine testing are summarized in Table 21.

Table 21: Available Values of the Parameters for Routine Wattmeter, Watthour Varmeter and

Varhour Testing

Parameter Available Values

Voltage (V) 69 to 480

Current (A) 0.5 to 30

Power Factor 0 to 1.0

Phase Angle 0 to 360°

Frequency (Hz) 50*, 60, 400*

* Tests at 50 and 400 Hz are limited to voltages of 240 V or less and

currents of 5 A or less.

If necessary, measurements can sometimes be made at other values of

these parameters. These would, however, be considered special tests. Separate, specific arrangements and a higher fee will be charged than for a

routine calibration. Prior to the calibration, the meters

are energized for between 1 and 4

hours at rated voltage and current on

one range. A calibration consists of at

least two sets of measurements taken

over a minimum period of 2 days.

160
56nOS-56210M

For wattmeters, the values of the

reported corrections (in watts) generally have uncertainties of ±0.05 per- cent of the full scale range in volt-amperes. For watthour meters,

the reported values of the percentage

registration generally have uncertainties of ±0.05 percent of the indicated

value. Special, higher accuracy tests can be arranged for an additional fee. The uncertainties for power or energy

measurements in these special tests may be as low as ±0.01 percent if the

short-term standard deviation of the

device under test is appropriately

small. For the highest accuracy, voltages are limited to 120 V and cur- rents to 5 A.

Wattmeter calibrations at other

than power frequencies are considered Special Tests and must be ar- ranged on an individual basis. The

following limitations apply:

A. Instruments must have separate voltage and current input terminals. B. The instrument must have a

self-contained power indicator, or provide a direct current or voltage

signal which is proportional to power,

or provide an output frequency which

is proportional to the power.

C. Measurements are generally

limited to sinusoidal signals at fre- quencies between dc and 100 kHz.

Input signal levels should not exceed

240 V and 5 A.

D. Instruments will be tested in the as-received condition, and test uncertainties will be based in part on

the performance of the instrument

during the test. The Measurement Assurance Pro- gram for electric energy is designed

to evaluate the performance of en- ergy-measuring systems at the cus- tomer's laboratory. A NIST-owned,

transport standard watthour meter of

known stability is measured by NIST.

It is then shipped to and measured by

the customer, and shipped back to NIST. NIST analyzes the data and

provides a report to the customer in- dicating the total uncertainty of his measurement. This procedure enables

the customer's standards to be measured relative to NIST standards

without the downtime encountered

when the customer's standards are shipped to and calibrated by NIST. In addition, and more important to those who calibrate standard

watthour meters, the NIST MAP

standard can be used by customers to evaluate their measurement process

in a convenient and cost-effective way.The uncertainty of a MAP includes

the effects of the long-term and

short-term instabilities of the NIST

calibration system, the customer's cal- ibration system, and the transport

standard. Typically, the uncertainty in a well-controlled comparison ranges

between ±0.03 percent and ±0.05

percent.

The Electricity Division maintains an active program of research and development in the area of electric power and energy measurements.

This program often enables NIST to provide measurement support for watt and watthour meters beyond that

listed in this section. Special tests will generally be conducted when the fol- lowing conditions prevail:

A. The requested tests are fully

developed and documented.

B. There is a significant technical or economic justification for

traceability of the test on the item to national standards.

C. There has not been a routine or recurrent need for the test.

161
References — Power and Energy

Measurements, Low Frequency

Digitally Synthesized Power Calibration Source, N. M. Oldham, O. B. Laug, and B. C. Waltrip, IEEE

Trans. Instrum. Meas., IM-36, No.

2, 341 (June 1987).

NBS Wideband Sampling Wattmeter,

G. N. Stenbakken, O. B. Laug,

A. G. Perry, B. A. Bell, and T. H.

Kibalo, Natl. Bur. Stand. (U.S.),

Tech. Note 1221 (May 1987).

A Wideband Sampling Wattmeter,

G. N. Stenbakken, IEEE Trans. Power Appar. Syst., PAS-103, No.

10, 2919 (Oct. 1984).

A Calibration Service for Wattmeters

and Watthour Meters, J. D. Ramboz and R. C. McAuliff, Natl. Bur. Stand. (U.S.), Tech. Note 1179

(July 1983).

A Measurement Assurance Program

for Electric Energy, N. M.

Oldham, Natl. Bur. Stand. (U.S.),

Tech. Note 930 (Sept. 1976).

Transfer of the Kilowatthour, S. R. Houghton, IEEE Trans. Power Appar. Syst., PAS-94, No. 4, 1232

(July-Aug. 1975).

Sampling Techniques for Electric

Power Measurement, R. S. Turgel,

Natl. Bur. Stand. (U.S.), Tech.

Note 870 (June 1975).

A Current Comparator System to Establish the Unit of Electrical Energy at 60 Hz, K. J. Lentner, IEEE

Trans. Instrum. Meas.,

IM-23, No. 4, 334 (Dec. 1974).

162
61110S-61190S

G

Microwave Measurements

G. 1 Bolometer Units, RF and Microwave

Technical Contacts:

Ronald A. Ginley

Tel: 303/497-3634

Manley P. Weidman

Tel: 303/497-3516

Kathy Hillen Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328.

Test No. Items

611 lOS Effective Efficiency and Reflection Coefficient of Coaxial Thermistor Mounts at Specified Frequency in Range 0.1 to 10 MHz

61 11 IS Each Additional Frequency for 61 HQS

61120S Calibration Factor, Effective Efficiency,

and Reflection Coefficient of Coaxial

Thermistor Mounts at 10 MHz intervals within 10-100 MHz

61121S Calibration Factor, Effective Efficiency,

and Reflection Coefficient of Coaxial

Thermistor Mounts at 25 MHz intervals within 100-500 MHz and 1000 MHz

61122S Calibration Factor, Effective Efficiency,

and Reflection Coefficient of Coaxial

Thermistor Mounts at 10 MHz intervals within 10-100 MHz and 25 MHz intervals within 100-500 MHz and 1000 MHz

61123S Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial

Thermistor Mounts at 50-MHz Intervals within

1-2 GHz

61124S Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thermistor

Mounts at 100-MHz Intervals within 2-4 GHz

61125S Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thermistor

Mounts at 200-MHz Intervals within 4-8 GHz

Test No. Items

61126S

61127S

61128S

61129S

61144S

61146S

61147S

61148S

61149S

61155S

61190S

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thermistor

Mounts at 200-MHz Intervals in the Range

8-12.4 GHz

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thcrmislor

Mounts at 250-MHz Intervals in the Range 12.4-18 GHz

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thermistor

Mounts at 1-GHz Intervals in the Range 1-18 GHz

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Coaxial Thermistor

Mounts at 1-GHz Intervals in the Range

18-26 GHz

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts at 200-MHz Intervals within

8.2-12.4 GHz (WR90)

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts at 250-MHz Intervals within

12.4-18.0 GHz (WR62)

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts at a Specified Frequency

within 18-26.5 GHz (WR42)

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts at a Specified Frequency

within 26.5-40 GHz (WR28)

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts at a Specified Frequency

within 42-46 GHz (WR22)

Calibration Factor, Effective Efficiency, and

Reflection Coefficient of Rectangular-Waveguide

Thermistor Mounts of Specified Frequency

within 94-96 GHz (WRIO)

Special Microwave and RF Power Measurement

Services, by Prearrangement

163
Coaxial Thermistor Mounts, RF and

Microwave (61110S-61190S)

Calibration services are available for thermistor mounts with 7 mm,

Type N, and 3.5 mm connectors. Thermistor-type bolometer units have

shown adequate stability over long

periods of time (approximately 10

years) and warrant long recalibration

intervals. Three to five year recalibration intervals are recommended once

the stability of a bolometer unit has

been verified. Assistance is available for applying

published, technically valid measure- ment techniques in lieu of previously

available NIST calibration services

for coaxial and waveguide calorimeters, thermoelectric power meters,

and bolometer coupler units The

attainable limits of measurement

uncertainty using these techniques

are comparable to those of the previously available calibration services for these devices.

The calibration reports give the

magnitude of the reflection coefficient, effective efficiency, and calibra- tion factor of the bolometer unit.

Definitions: Calibration results are reported in the

following quantities:

Effective Efficiency T|e

The effective efficiency -rie is the

ratio of the bolometrically substi- tuted dc power in the bolometer

unit to the net cw rf microwave

power absorbed by the bolometer

unit.

Bolometrically Substituted dc

Power

The bolometrically substituted dc

power is the change in dc (or audio frequency) bias power re- quired to maintain the resistance

of the bolometer element at a constant value following the application of rf or microwave

power.

Calibration Factor, Kb

The calibration factor is the ratio of the bolometrically substituted

dc power in the bolometer unit

to the cw rf microwave power in- cident upon the bolometer unit. KB=-ne(i-|rp).

Reflection Coefficient Magnitude,

|r|

The reflection coefflcient magnitude is the ratio of the reflected wave voltage amplitude to the in- cident wave voltage amplitude.

The reflection coefficient magnitude is included in the Report of

Calibration for all power measurements. All calibrations are performed under typical ambient

laboratory conditions at 23 °C,

and an atmospheric pressure of

approximately 8.4 ± 0.2 x 10'* Pa

at Boulder, Colorado.

164
61110S-61190S

Coaxial Thermistor Mounts

(61110S-61129S)

Only bolometer units designed for low-frequency operation will be cali- brated below 100 MHz.

Specify frequency in range 0.1 to 10

MHz for special low-frequency

bolometer units (Test No. 61 11 IS).

Values for Tie and |r| are calculated

from voltage and resistance measurements.

'ne = (Pdc)/(Prf), where Prf = VVRp,

where Rp is the parallel equivalent

resistance and Pdc is the bolometrically substituted dc power in the

bolometer. The uncertainty in measuring Tje is ±0.3 percent.

Measurements are made at the fol- lowing frequencies:

Range

10-100 MHz

100-500 MHz

1000 MHz

1-2 GHz

2-4 GHz

4-8 GHz

8-12.4 GHz

12.4-18 GHz

18-26.5 GHz

Frequency or Interval

10 MHz intervals 25 MHz intervals 1000 MHz

50-MHz intervals 100-MHz intervals 200-MHz intervals 200-MHz intervals 250-MHz intervals

1 GHz intervals Measurement uncertainties for effective efficiency and calibration factor

will vary from approximately 1.0 to

3.5 percent depending on the fre- quency and the characteristics of the

unit being calibrated such as connector type, reflection coefficient, and re- peatability.

Waveguide Thermistor Mounts

(61144S-61155S)

Measurements of effective efficiency,

efficiency factor, and reflection coeffi- cient are made for various waveguide

sizes as follows:

Frequency Measurement

Wave- Range Frequency or guide (GHz) Interval WR90 8.2-12.4 200-MHz intervals WR62 12.4-18.0 250-MHz intervals WR42 18-26.5 Specify frequency

WR28 26.5-40 Specify frequency

WR22 42-46 Specify frequency

WRIO 94-96 Specify frequency

The measurement uncertainty of

effective efficiency will vary from

1 to 3.5 percent depending on the

frequency and the characteristics

of the unit being calibrated.

References — Power Meters, RF and

Microwave

WR-10 Millimeter Wave Microcalorimeter, M. Weidman and P. Hudson, Natl. Bur. Stand. (U.S.),

Tech. Note 1044 (June 1981).

A Semiautomated Six-Port for Measuring Millimeter-Wave Power and

Complex Reflection Coefficient, M.

Weidman, IEEE Trans. Micro.

Theory Tech., MTT-25, 12 (Dec.

1977).

Performance Characteristics of an Automated Broad-Band Bolometer

Unit Calibration System, E. Komarek, IEEE Trans. Micro. Theory Tech., MTT-25, 12 (Dec. 1977).

Theory of UHF and Microwave Measurements Using the Power Equation Concept, G. Engen, Natl. Bur.

Stand. (U.S.), Tech. Note 637 (Apr.

1973).

165
Application of an Arbitrary Six-Port

Junction to Power Measurement

Problems, G. Engen and C. Hoer,

IEEE Trans. Instrum. Meas., IM21, 470 (Nov. 1972).

WR-15 Microwave Calorimeter and

Bolometer Unit, M. Harvey, Natl. Bur. Stand. (U.S.), Tech. Note 618

(May 1972).

Accurate Microwave High-Power

Measurements Using a Cascaded

Coupler Method, K. E. Bramall, J. Res. Natl. Bur. Stand. (U.S.), 75C,

Nos. 3 and 4, 185 (July-Dec. 1971).

A Method of Determining the Mismatch Correction in Microwave

Power Measurements, G. Engen,

IEEE Trans. Instrum. Meas.,

IM-17, 4 (Dec. 1968).

Bolometric Microwave Power Calibration Techniques at the National

Bureau of Standards, R. F. Desch

and R. E. Larson, IEEE Trans.

Instrum. Meas., IM-12, 1 (June

1963).

A Bolometer Mount Efficiency Measurement Technique, G. Engen,

J. Res. Natl. Bur. Stand. (U.S.),

65C, 113 (Apr.-June 1961).

A Transfer Instrument for the Inter- comparison of Microwave Power

Meters, G. Engen, IRE Trans. In- strum. Meas. 19, 202 (Sept. 1960).

A Refined X-Band Microwave Microcalorimeter, G. Engen, J. Res.

Natl. Bur. Stand. (U.S.), 63C, 77

(1959).

166
61210S-61250S

G Microwave Measurements

G.2 Attenuators, RF and Microwave

Technical Contacts:

' Ronald A. Ginley Manley P. John R. Juroshek Kathy Hillen

Tel: 303/497-3634 Weidman Tel: 303/497-5362 Administrative

^ Tel: 303/497-3516 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 61210S Coaxial Fixed and Variable Attenuators, Frequency

Range 10 MHz to 26 GHz, Attenuation 0 to 50 dB

6121 IC Coaxial Fixed and Variable Attenuators, Measured at 30 MHz, Attenuation 0 to 120 dB

61215C Waveguide-Below Cutoff (Piston)

Attenuators, Coaxial Connector, Measured at 30 MHz, Attenuation 0-120 dB (Total Insertion Loss)

61230S Rectangular Waveguide Fixed and Variable

Attenuators, Specify Frequencies for Waveguide Sizes WRIO, WR22, WR28, andWR42,

0-50 dB

61240S Attenuation Measurements of Three-Port and Two-Port Devices at 1.25 MHz, 0-6 dB

61250S Special Attenuation Measurements, by

Prearrangement

Attenuators, RF and Microwave

(61210S-61250S)

Specific attenuation measurements

are available for 14 mm, 7 mm. Type

N, and 3.5 mm connectors. Measurements not listed may possibly be pro- vided (61250S) if sufficient advance

notice is given and resources permit.

The cost of such services must be ne- gotiated and will, in general, be

higher than other established services. Consultation by telephone

or written correspondence is suggested. Often a measurement tech- nique can be suggested that will permit the customer to perform his calibrations in-house with appropriate

reference to other NIST-supported

standards.

Fixed and Variable Coaxial

Attenuators (61210S and 61211C)

Coaxial fixed and variable attenuators

are measured on the NIST Dual Six- Port Automatic Network Analyzer

(DSPANA) over the frequency range

10 MHz to 26.5 GHz.

In addition to measurements per- formed on the DSPANA, measure- ments at a fixed frequency of 30 MHz

are available referenced to the NIST

waveguide below cutoff standard at

this frequency.

Coaxial attenuators are normally

measured in a system having a

characteristic impedance of 50 ohms.

Typical uncertainties range from 0.01 dB to 1 dB depending on the nominal

attenuation, connector repeatability,

and frequency.

Waveguide Below-CutofT Piston Attenuator Measurements at 30 MHz

(61215C)

Incremental attenuation is the change

in attenuation of an adjustable attenuator between a reference set- ting (usually zero) and any other setting. The same restraints on system

conditions apply as for attenuation.

The term "attenuation difference"

is sometimes applied to this case and usually refers to two nonzero

settings.

Measurements on waveguidebelow-cutoff (piston) attenuators are performed at 30 MHz. These attenuators are normally quite stable and

seldom need recalibration unless

damaged or mechanically worn.

Since any laboratory can perform

independent checks to determine

continuing repeatability and linearity

of attenuation, we do not recommend

167
periodic NIST recalibrations. This

recommendation is also made be- cause more damage can be suffered

in transit than in daily use. In any

measurement, the maximum power

delivered to the test attenuator will not exceed 400 mW. If the attenuator cannot tolerate this power level, some

reduction of measurement range will be required.

Piston attenuators are normally cal- ibrated in a system having a characteristic impedance of 50 ohms. Since

only measurements of incremental at- tenuation are made on this type of at- tenuator, Type BNC, C, TNC, and

similar connectors are acceptable, but

precision connectors are preferred to reduce leakage. Limits of uncertainty

depend upon the quality of the atten- uator and connectors, as well as upon

the VSWR of the attenuator, and the

magnitude of attenuation. Typical sys- tematic uncertainties range from

0.003 to 0.005 dB/10 dB of attenuation. Total insertion loss must be less than 120 dB.

Rectangular Waveguide Fixed and

Variable Attenuators (61230S)

Fixed and variable (usually rotary

vane) waveguide attenuators are cali- brated on the NIST DSPANA. Service is available for frequencies

corresponding to waveguide sizes WRIO, WR22, WR28, and WR42.

Requested measurements for vari- able attenuators should be for a minimum number of settings at a single

band-center frequency and be suffi- cient to determine the characteristics

of the device. Previously calibrated

units should not be resubmitted unless tests performed by the user indi- cate a shift in values. The uncertainty is a function of resettability, internal leakage, and quality of flanges. Except for measurements made on the NIST

Dual Six-Port Automatic Network

Analyzer, the uncertainty is also a

function of the VSWR of the waveguide ports. Devices submitted should

be in the best possible condition to

justify calibration and to ensure longterm stability of measured values. Typical uncertainties range from 0.01

to 0.10 dB.

Attenuation Measurements at 1.25 MHz (61240S)

An additional measurement service is available for attenuation measure- ments of special three-port devices at 1.25 MHz. A measurement system

has been developed to measure the

change in the ratio S21/S31 of special

stable two-position three-port devices,

sometimes called voltage doublers, at 1.25 MHz. The device must have an

input for a 1.25-MHz source (port 1), a reference output (port 3), and an

output (port 2) with a level switchable to two different values. The two

levels of the bi-level output have a nominal ratio of 6.0206 dB.

If Pri is the reference power level when the bi-level output is at level 1 (Pbi), and Pr2 is the reference power

level when the bi-level output is at

level 2 (Pb2), then parameter measured is given by the following equation:

10 Logio (§^) - 10 Logio (^) dB

frl I r2

where the subscripts (1) and (2) refer

to the switch positions 1 and 2, re- spectively. The above is equivalent to

10 log,

S2l(l)/S3l(l)

S2.(2)/S3,(2)

168
61 21 OS;-61250S

The loads presented to the two

outputs are 50 ohms. The device must

allow the signal input to be of such

strength that the bi-Ievel output is at least 10 mW in the high-level position. The total uncertainty of the measurement system in measuring a 6-dB

change in attenuation is estimated to have a systematic error no greater

than 5 |xB and a random error of

about 3 |xB, where 1 |xB= 10"^ dB or about 2.3 ppm of the power ratio. Two-port step attenuators having a nominal change in attenuation of

6 dB can also be measured by this system at 1.25 MHz.

References— Attenuators, RF and

Microwave

1.25 MHz Attenuation Measurement

System, R. A. Ginley and C. M.

Allred, IEEE Trans. Instrum. Meas., IM-35, No. 4, Pt. 1 (Dec.

1986).

Effects of Connectors and Adapters on Accurate Attenuation Measurements at Microwave Frequencies, R. W. Beatty, IEEE Trans. In- strum., IM-13, 272 (Dec. 1984).

"Thru-Reflect-Line": An Improved

Technique for Calibrating the Dual

Six-Port Automatic Network Analyzer, G. F. Engen and C. A. Hoer,

IEEE Trans. Micr. Theory Tech.,

MTT-27, 987 (Dec. 1979).

A Network Analyzer Incorporating

Two Six-Port Reflectometers,

C. A. Hoer, IEEE Trans. Micr.

Theory Tech., MTT-25, 1070

(Dec. 1977).

The Six-Port Reflectometer: An Alternative Network Analyzer, G. F. Engen, IEEE Trans. Micr. Theory

Tech., MTT-25, 1075 (Dec. 1977).

Insertion Loss Concepts, R. W.

Beatty, Proc. IEEE 55, 6, 663 (June

1964).

RF Attenuation, D. Russell, Proc. IEEE 55, 6, 942 (June 1967).

Application of Waveguide and Circuit

Theory to the Development of Accurate Microwave Measurement

Methods and Standards, R. W.

Beatty, Natl. Bur. Stand. (U.S.),

Monogr. 137 (Aug. 1973).

Specifications and Test Methods for Fixed and Variable Attenuators, dc

to 40 GHz, IEEE Standard 474

(1973).

Basic Theory of Waveguide Junctions

and Introductory Microwave Net- work Analysis, D. M. Kearns and

R. W. Beatty, Intl. Ser. of Monogr.

in Electromag. Waves, 13, 59,

Pergammon Press, New York, NY

(1967).

169
61310S-61340S

G. Microwave Measurements

G.3 Coaxial and Waveguide Terminations,

Reflection Coefficients

Technical Contacts:

Ronald A. Ginley

Tel: 303/497-3634 Manly P. WeidmanTel: 303/497-3516 John R. Juroshek

Tel: 303/497-5362 Kathy Hillen Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 61310S Complex Reflection Coefficient of Coaxial

Terminations, Frequency Range 10 MHz to 26 GHz

61320S Complex Reflection Coefficient of Rectangular

Waveguide Terminations with Standard

Flange Connectors, Specify Frequency for Waveguide Sizes WRIO, WR22, WR28, and WR42

61340S Special Reflection Coefficient Measurements,

by Prearrangement

Coaxial and Waveguide Terminations,

Renection Coefficient (61310S-61320S)

Services provided in this category are

for passive devices over the frequency

range from 10 MHz to 95 GHz.

Available calibration frequencies are

listed in the test descriptions. Highest

accuracy is obtained only for stan- dards equipped with precision coaxial connectors or waveguide flanges.

Standards submitted for calibration

should be in good repair and,

except for very minor cleaning of con- nector surfaces, should require no re- calibration maintenance. NIST does

not provide repair services. Items re- ceived requiring maintenance will be

returned to the customer, and a handling fee will be charged.

Coaxial Terminations (61310S)

Services are available for complex

coefficient of devices with 14 mm, 7

mm. Type N, and 3.5 mm connectors. Measurements on coaxial devices in the frequency range 10 MHz to 26

GHz are made on the NIST Dual Sbc- Port Automatic Network Analyzer

(DSPANA). Typical uncertainties are ±0.005 to 0.015 depending on the

frequency and connector repeatability.

Waveguide Terminations (61320S)

Waveguide terminations are measured on the NIST DSPANA's.

Waveguide terminations are usually

quite stable and need not be resubmitted unless tests performed by the user indicate a shift in values. The

terminations must be fitted with stan- dard waveguide flange connectors. The faces of these flanges should be

machined flat and smooth and should

not contain protrusions or indentations. Considerable care must be

exercised in keeping the mating connector flange surfaces smooth and

clean. Accurate alignment of the

interior surfaces of the joining waveguides at the flange junction also is very important. The back of the

flange which makes contact with the

connecting bolts should be nominally

flat and free of soft materials, including paint. The connecting holes of

the flange should be symmetrically

and accurately aligned to the rectan- gular waveguide opening. These

precautions must be observed when

using a waveguide termination in a precision measurement system.

Assigned limits of uncertainty

depend upon the quality of the

flanges and the frequency range. Typical uncertainties are 0.001 to

0.015.

170
61310S-61340S

References — Coaxial and Waveguide

Terminations, Reflection Coefficients

"Thru-Reflect-Line": An Improved

Technique for Calibrating the Dual

Six-Port Automatic Network Analyzer, G. F. Engen and C. A. Hoer,

IEEE Trans. Micr. Theory Tech.,

MTT-27, 987 (Dec. 1979).

A Network Analyzer Incorporating

Two Six-Port Reflectometers,

C. A. Hoer, IEEE Trans. Micr.

Tech., MTT-25, 1070 (Dec. 1977).

The Six-Port Reflectometer: An Alternative Network Analyzer, G. F. Engen, IEEE Trans. Micr. Theory

Tech., MTT-25, 1075 (Dec. 1977).

Millimeter Attenuation and Reflection Coefficient Measurement System, B. C. Yates and W. Larson,

Natl. Bur. Stand. (U.S.), Tech.

Note 619 (1972).

A Guide to the Use of the Modified

Reflectometer Technique of VSWR

Measurement, W. J. Anson, J. Res.

Natl. Bur. Stand. (U.S.), 65C, 4, 217 (Oct.-Dec. 1961). (The measurement technique utilized in re- flection measurements is described

in this paper.)

171
61410S-61450S

G Microwave Measurements

G.4 Phase Shifters, RF and Microwave

Technical Contacts:

Ronald A. Ginley Manley P. Gene Marler Kathy Hillen

Tel: 303/497-3634 Weidman Tel: 303/497-5455 Administrative

Tel: 303/497-3516 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 61410S Coaxial Fixed and Variable Phase Shifters; Characteristic Phase Shift Difference; Precision Connectors; Measured at 30 MHz, Range 0-360° 61411S Coaxial Fixed and Variable Phase Shifters; Phase Shift Difference; Precision Connectors; Frequency Range 1-26 GHz, Phase Range 0-360° 61420S Variable Rectangular Waveguide Phase Shifters; Phase Shift Difference; Specify Frequencies

for Waveguide Sizes WRIO, WR22, WR28, WR42, Range 0-720° 61450S Special Tests of Phase Shifters, by Prearrangement

Phase Shifters, RF and Microwave

(61410S-61450S)

The specific phase shift services listed below are available on a limited basis

depending on other demands and

staff availability. Measurements not

listed may possibly be provided if suf- ficient advance notice is given. The

cost of such services must be negotiated and will, in general, be higher

than the established phase shift services. Consultation by telephone or

written correspondence is suggested.

Often a measurement technique can be suggested that will permit the cus- tomer to perform calibrations in- house with appropriate reference to other NIST-supported standards.

Microwave devices made on gallium arsenide microelectronic chips MMICs (monolithic microv\/aveImil- limeter-wave integrated circuits) offer the potential of

greatly reduced costs compared to conventional

"plumbing" if produced in large numbers for civilian applications. NIST supports the emerging MMIC industry

by providing measurements and standards for evaluating

the performance of wafer probe stations such as this one.

Ill
61410S-61450S

Coaxial Phase Shifters (61410S and

61411S)

Fixed and variable coaxial two-ports

are measured on the NIST Dual Six- Port Automatic Network Analyzer

over the frequency range 10 MHz to 26 GHz. In addition, measurements

can be performed with reference to a precision variable air line at 30 MHz.

Because of the specialized nature of

coaxial phase shifting components,

prior discussions should be held with

NIST staff before submission of any

devices to NIST. Items to be cali- brated must be fitted with connectors having a known plane of reference,

such as sexless precision connectors, or Type N connectors meeting Mil.

Std. C39012. The phase angle measured is ^-f-360n, where n is an

integer. The value of n is not deter- mined.

Limits of uncertainty are:

Frequency Range Uncertainty

30 MHz 0-360° 0.1-0.5° 0.1-26 GHz 0-360° 0.5°

Phase Shifters (61420S)

For a rectangular waveguide, the

measurement services are limited to phase shift difference at frequencies

below 18 GHz. Measurements are made on continuously variable waveguide phase shifters with the zero value of the scale as the normal refer- ence position. Since 360 mechanical

degrees of rotation represent 720

electrical degrees, attention should be

given to the relationship between dial indication and actual mechanical position of the rotating vane assembly.

The uncertainty is approximately

the same as for coaxial devices.

Gallium arsenide wafer on which NIST has fabricated

standard transmission lines for the calibration of MMIC

(monolithic microwave/millimeter-wave integrated cir- cuit) wafer probe stations from 50 MHz to 40 GHz. The

lines are of coplanar configuration from gold films patterned on the wafer surface.

References — Phase Shifters,

RF and Microwave

UHF and Microwave Phase Shift Measurements, D. A. Ellerbach,

Proc. IEEE 55, 6, 960 (June 1967).

173
61510S

G Microwave Measurements

G. 5 Dimensional Verification of

Coaxial Air Line Standards

Technical Contacts:

John R. Juroshek Ronald A. Ginley Manley P. Weidman Kathy Hillen

Tel: 303/497-5362 Tel: 303/497-3634 Tel: 303/497-3516 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 61510S Dimensional Measurement of Air Lines and

Verification of Characteristic Impedance

from Dimensional Measurements 18 GHz

Coaxial Air lines (61510S)

Dimensional measurements are made

on the inner and outer conductors

of a headless, coaxial, air line stan- dard. The characteristic impedance

of the air line standard is then computed from these dimensional

measurements. The service is currently available for 14 mm, 7 mm,

Type N, and 3.5 mm air line stan- dards. The computations for characteristic impedance is made

over the normal operating frequency

range of the air line standard.

j 174
61620S

G

Microwave Measurements

G. 6 Dielectric Material Measurements

Technical Contacts:

Claude M. Weil

Tel: 303/497-5305 William A. Kissick Kathy Hillen

Tel: 303/497-3339 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 61620S Special Tests for Dielectric Materials 0.05 to 18 GHz

Two kinds of measurement services are available: either a) a high accuracy (Acr = 0.5%) measurement per- formed in a resonant cavity at the

single frequency of 10 GHz, or b) a measurement of lesser accuracy per- formed in a 7 mm coaxial transmission line covering the frequency range

0.05 to 18 GHz. A measurement

service, similar to the latter, and per- formed in WR-284 waveguide (2.6-

3.95 GHz) and WR-90 waveguide

(8.2-12.4 GHz) is also provided. For

broadband measurements, the number of frequencies at which dielectric measurement data are provided, shall be selected by the customer.

References — Dielectric Material

Measurements

Ad /ances in NIST Dielectric Measurement Capability Using a Mode-filtered Cylindrical Cavity, E. Vanzura and W. A. Kissick,

IEEE Intl. Micr. Symp. Digest,

MTT-S, Vol. 3, 901 (1989).

Special Tests for Dielectric Materials

(61620S)

A provisional service is now available

for complex dielectric permittivity

measurements of low-loss dielectric materials.

The service is currently limited to

solid materials that are linear, homogeneous, isotropic and non-magnetic;

measurements can only be performed

at room temperature (23 °C),

currently.

Measurements will be performed on materials meeting the above criteria, that are supplied by the cus- tomer; the customer has the option of

machining the material to the re- quired sample specifications or leav- ing this task to NIST to perform.

Alternatively, NIST can supply machined samples of certain dielectric reference materials, such as cross- linked polystyrene (rexolite), together

with the dielectric data that characterizes these materials.

175
62020S-62133S

Noise Temperature Measurements

Technical Contacts:

J. Wayde Allen Sunchanna Kathy Hillen

Tel: 303/497-5871 Perera Administrative

Tel: 303/497-3546 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 62020S Special Noise Temperature Measurements

(Electromagnetic), by Prearrangement

62100S Noise Temperature of Coaxial Noise Source, Type N

Precision, APC 3.5, or 14-mm Connectors, at 30 MHz

or 60 MHz; VSWR < 1.2, Temperature:

77 K-15,000 K, ENR < 17 dB

62101S Each Additional 62100S Item Tested at Same

Frequency within the Same System

62110S Noise Temperature of Coaxial Noise Source, Type N

Precision, 14 mm, or APC 7 Connectors; Continuous Frequencies 2.0-12.0 GHz, Reflection

Coefficient <0.2, Temperature: 77 K-15,000 K, ENR <17 dB

621 lis Each Additional 621 lOS Item Tested at Same

Frequency within the Same System

621 12S Noise Temperature of Coaxial Noise

Source, APC 3.5 Connector; Continuous

Frequencies 2.0-12.0 GHz, Reflection

Coefficient < 0.2, Temperature:

77 K-15,000 K, < 17 dB

621 13S Each Additional 621 12S Item Tested at Same Frequency within the Same System

621 15S Special Service for Waveguide Noise Sources in WR284, WR187, WR137, WR112, and WR90;

Continuous Frequencies within the Bands from

2.6 to 12.0 GHz; Reflection Coefficient <0.2,

Temperature: 77 K-15,000 K, ENR <17 dB

Test No. Items

621 16S Each Additional 621 15S Item Tested at the Same

Frequency within the Same System

621 20S Noise Temperature of Rectangular Waveguide Noise

Sources at Specific Frequencies in WR62 (12.4, 13.5, 14.0, 15.0, 16.0, 16.5, 17.0, 18.0 GHz) and WR90 (8.2, 9.0, 9.5, 9.8, 10.0, 10.5, 11.2, 11.8, 12.4 GHz);

Reflection Coefficient <0.09, Temperature:

9,000 K-17,000 K, ENR < 17.6 dB

62121S Each Additional 62120S Item Tested at Same

Frequency within the Same System

62130S Noise Temperature of WRIO Noise Sources,

Continuous Frequencies between 94.5 GHz and

96.6 GHz, Reflection Coefficient <0.2,

Temperature 77 K-15,000 K, ENR <17 dB

62131S Each Additional 62130S Item Tested at the Same

Frequency

62132S Noise Temperature of WR15 Noise Sources,

Continuous Frequencies between 55.0 GHz and

64.5 GHz, Reflection Coefficient <0.09,

Temperature 300 K-15,000 K, ENR < 17 dB

62133S Each Additional 62132S Item Tested at the Same

Frequency

176
62020S-62133S

Noise Temperature Measurements —

Electromagnetic (62020S)

Special-test services for the measure- ment of electromagnetic thermal

noise are offered in limited frequency

coverage from 30 MHz to 96.5 GHz

and include measurements through

adaptors and out-of-range noise temperatures. Some gaps in the fre- quency coverage exist. In some

frequency regions, only spot fre- quency measurements are available. Depending on the frequency coverage

available, noise sources submitted for measurement will be compared, via one of three different types of ra- diometers, against a hot or cold primary reference standard or a transfer standard. Since there are limitations

which are a function of the noise

standards and radiometer available,

the customer should check with the

technical contacts listed at the beginning of this section before submitting

a device for calibration.

Noise Sources (62100S-62133S)

Noise temperature measurements are

available on single-port, coaxial, and

rectangular waveguide noise sources under conditions of continuous, un- modulated operation. Precision coaxial connectors or clean, smooth, and

flat standard EIA waveguide flanges are required. Complete operating in- structions and special electronic connectors should be supplied, and

pertinent operating conditions

(voltages, circuits, etc.) specified for the noise source to be measured.

Devices submitted that are not of sufficient quality or not mechanically

compatible with the measuring system

will be rejected and an appropriate

fee charged. Availability of measure- ments at specific frequencies and for various connector types are specified

above. Generally, an attempt is being

made to expand services to include more types of precision connectors and waveguide sizes. However, the

cost of measurements requiring the use of adaptors as part of the measurement process can be substantially

greater than the cost of measure- ments on sources with connectors mating directly to the measurement

system. Furthermore, measurement

results on devices submitted with

adaptors attached may apply only to the source/adaptor combination.

The limits of uncertainty vary with

noise temperature, reflection coefficient, and source and connector stability, but typically lie between 1 percent and 3 percent of the noise

temperature.

177
References — Noise Temperature

Measurements

A Derivation for the Noise Temperature of Horn-Type Noise Standards, W. C. Daywitt, Metrologia

21, 127 (Sept. 1985).

A Coaxial Noise Standard for the

1-GHz to 12.4-GHz Frequency

Range, W. C. Daywitt, Natl. Bur. Stand. (U.S.), Tech. Note 1074

(Mar. 1984).

The NBS WR62 and WR90 Refer- ence Noise Standards, C. K. S. Miller and W. C. Daywitt, Natl. Bur. Stand. (U.S.), NBSIR 84-3005

(May 1984).

The NBS Switching Radiometers,

C. K. S. Miller and W. C. Daywitt,

Natl. Bur. Stand. (U.S.), NBSIR

84-3004 (May 1984).

Design and Error Analysis for the

WRIO Thermal Noise Standard, W.

C. Daywitt, Natl. Bur. Stand.

(U.S.), Tech. Note 1071 (Dec.

1983).

Precision Measurement of Antenna

System Noise Using Radio Stars, D. F. Wait, IEEE Trans. Instrum. Meas., IM-32, 1 (Mar. 1983).

WR15 Thermal Noise Standard,

W. C. Daywitt, W. J. Foote, and E. Campbell, Natl. Bur. Stand. (U.S.),

Tech. Note 615 (Mar. 1972).

178
63100S-63400S

Electromagnetic Field Strength and Antenna « Measurements

/. 1 Microwave Antenna Parameter

Measurements

Technical Contacts:

Allen C. Newell Katie MacReynolds Andrew G. Repjar Kathy Ifillen 63100S-63400S 63100S 63200S Administrative

Tel: 303/497-3743 Tel: 303/497-3471 Tel: 303/497-5703 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.05, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Shipping Address: Room 1300, Bldg. 24, National Institute of Standards and Technology, 325 Broadway, Boulder,

CO 80303-3328

Test No. Items 63100S Gain and Polarization Calibrations of Standard Antennas Using Extrapolation Range

63200S Measurement of Pattern, Gain, and Polarization of Arbitrary Antennas Using Near-Field Scanning

Techniques

63300S Special-Test Service for Calibration of Probes Used

with Near-Field Scanning Facilities 63400S Special Consulting, Advisory, and Other Services

Antenna Parameter

Measurements (Microwave) —

General Information

Accurate measurements of antenna

gain, pattern, and polarization are generally available from about 1.0 GHz to about 65 GHz. However, be- cause the measurement accuracy, capability, and cost depend on the

frequency, type, and size of antenna,

and the parameters to be measured, a particular measurement service must

be negotiated in advance. Antennas

submitted for evaluation should be

mechanically and electrically stable in order to retain a calibration for a sig- nificant length of time. Antennas with

either coaxial or waveguide connectors can be measured; however, if coaxial connectors are employed, they

should be precision connectors to minimize uncertainties due to a lack of connector repeatability. In particular, the use of SMA connectors is strongly discouraged because of poor

connector repeatability. The following

methods and facilities are used for these measurements.

Gain and Polarization Calibrations

of Standard Antennas Using

Extrapolation Range (63100S)

This calibration service is offered primarily for determining the absolute

on-axis gain and polarization of stan- dard gain horns, which, in turn, are used as reference standards in determining the gain and polarization of

other antennas by the gain comparison technique. In the extrapolation

method three antennas are normally

utilized, and three pairwise combinations are determined. The received

signal transmitted between each pair

of antennas is measured as a function

of the separation distance between

the antennas. The antennas need not be identical, and no assumptions concerning the polarization are required.

The method is not well suited for pat- tern measurements but is the most

accurate technique known for absolute gain and polarization measurements. Above 1 GHz, the accuracies

are typically ±0.10 dB for gain measurements and ±0.05 dB/dB for polarization axial ratio measurements.

There are antenna size limitations as- sociated with existing NIST extrapolation ranges. These limitations depend

on the type of antenna, the fre- quency, and the desired measure- ments and accuracies. Therefore,

negotiations must be conducted prior

to submitting antennas for calibration

to ascertain whether all requirements

can be met.

179
Measurement of Pattern, Gain, and

Polarization of Arbitrary Antennas

Using Near-Field Scanning

Techniques (63200S)

With this technique, gain, pattern,

and polarization parameters are cal- culated from near-field amplitude and

phase measurements taken over a surface close to the test antenna. The

absolute gain can be determined to within about 0.15 dB, the polarization

axial ratio to within about 0.10 dB/

dB, and side lobe levels can be obtained down to -50 or -60 dB. The

exact uncertainties in these parameters will depend on such factors as the frequency, type, and size of antenna. Antennas with apertures up to about 3.5 meters in diameter can be

managed. Measurements can be made

from about 1.0 GHz to about 65

GHz. Measurements are most com- monly made over a plane surface in front of the antenna being evaluated,

but the capability also exists for measuring over a cylindrical or spherical

surface surrounding the antenna

when it is advantageous to do so. Calibrated probes are normally required

for these measurements. These nearfield scanning measurements are of- fered as a special-test service because

nearly every measurement is unique

and it is difficult to build up a

statistical history as required for a regular calibration service.

Special-Test Service for Calibrating

Probes Used with Near-Field

Scanning Facilities (63300S)

This special-test service is available to support those organizations that have

established their own near-field measurement facilities and need to characterize the probes used in per- forming the near-field measurements.

In order to achieve accurate results with either the planar, cylindrical, or

spherical near-field method, the

transmitting or receiving properties of

the probe must be known. With this information, the measured data can be corrected for the nonideal pattern

and polarization properties of the

probe. Probes are characterized by a

three-step process: (1) The on-axis

gain and polarization properties are measured using the extrapolation

technique described above; (2) the

far-field amplitude and phase pat- terns are measured for two nominally

orthogonal polarizations of the inci- dent field; and (3) the on-axis and

pattern data are combined to obtain

the probe correction coefficients at the desired lattice points for the measurement surface specified by the cus- tomer. The final output consists of a computer tape containing the measured far-field patterns and the calcu- lated probe coefficients. Typical types

of probes are open-ended waveguides

and small horns. Both linearly and

circularly polarized probes can be

evaluated.

Douglas Kremer makes adjustments before evaluating

and calibrating the performance of large, complex

antennas.

180
63100S-63400S

Special Consulting, Advisory, and

Other Services (63400S)

A variety of special consultation and

advisory services related to the measurements described above are avail- able upon request. These services are offered to disseminate NIST tech- nologies and to assist other organizations in establishing their own

measurement facilities and capabilities. Included are cooperative measurement programs. A customer

actually participates directly in the

measurement of his device in order to become familiar with the measure- ment methods and assist in the analysis of the results. This is a useful approach when one is attempting to establish a new measurement capability that is related to or based upon

NIST measurement techniques.

References — Microwave Antenna

Parameter Measurements

Accurate Determination of Planar

Near-Field Correction Parameters

for Linearly Polarized Probes,

A. G. Repjar, A. C. Newell, and

M. H. Francis, IEEE Trans. Antennas Propagat., Vol. 36, No. 6

(June 1988).

Improved Polarization Measurements

Using a Modified Three-Antenna

Technique, A. C. Newell, IEEE

Trans. Antennas Propagat., Vol. 36,

No. 6 (June 1988).

Gain and Power Parameter Measurements Using Planar Near-Field

Techniques, A. C. Newell, Robert

Ward, and Edward McFarlane,

Hughes Aircraft Company, IEEE

Trans. Antennas Propagat., Vol. 36,

No. 6 (June 1988).

Error Analysis Techniques for Planar

Near-Field Measurements, A. C. Newell, IEEE Trans. Antennas

Propagat., Vol. 36, No. 6 (June

1988).

Effect of Random Errors in Planar

Near-Field Measurement, A. C. Newell and C. F. Stubenrauch,

IEEE Trans. Antennas Propagat.,

Vol. 36, No. 6 (June 1988).

An Efficient and Accurate Method

for Calculating and Representing

Power Density in the Near ZLone of

Microwave Antennas, R. L. Lewis

and A. C. Newell, IEEE Trans. Antennas Propagat., Vol. 36, No. 6 (June 1988).

Plane-Wave Scattering-Matrix Theory

of Antennas and AntennaAntenna Interactions, D. M. Kerns,

Natl. Bur. Stand. (U.S.), Monograph 162 (June 1981).

Plane-Wave Scattering-Matrix Theory

of Antennas and AntennaAntenna Interactions: Formulation

and Applications, D. M. Kerns, J. Res. Natl. Bur. Stand. (U.S.), 80B,

I, 5051 (Jan.-Mar. 1976).

Upper-Bound Errors in Far-Field Antenna Parameters Determined from

Planar Near-Field Measurements,

A. D. Yaghjian, Natl. Bur. Stand.

(U.S.), Tech. Note 667 (Oct. 1975).

Accurate Measurement of Antenna

Gain and Polarization at Reduced

Distances by an Extrapolation

Technique, A. C. Newell, R. C.

Baird, and P. F. Wacker, IEEE

Trans. Antennas Propagat., AP-21,

4, 418 (July 1973).

Determination of Both Polarization

and Power Gain of Antennas by a Generalized 3-Antenna Measurement Method, A. C. Newell and D.

M. Kerns, Electronics Letters, 7, 7, 68 (Feb. 1971).

Correction of Near-Field Antenna

Measurements Made with an Arbitrary but Known Measuring Antenna, D. M. Kerns, Electronics

Letters, 6, 11, 346 (May 1970).

New Method of Gain Measurement

Using Two Identical Antennas,

D. M. Kerns, Electronics Letters 6, II, 348 (May 1970).

181
64100S-64300S

/Electromagnetic Field Strength and Antenna

Measurements

1.2 Field Strength Parameter Measurements

Technical Contacts:

Galen H. Koepke Motohisa Kanda Kathy Hillen

Tel: 303/497-5766 Tel: 303/497-5320 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 64100S Special-Test Service for Antennas/Field Strength

Measurements, Utilizing the Transverse Electromagnetic (TEM) Cell Method (10 kHz-300 MHz)

64200S Special-Test Service for Antennas/Field Strength

Measurements, Utilizing the Open-Field Method

64300S Special-Test Service for Antennas/Field Strength/

Reflectivity Measurements, Utilizing the Anechoic-Chamber Method

Special-Test Service for Antennas/

Field Strength Measurements,

Utilizing the Transverse

Electromagnetic (TEM) Cell Method

(64100S)

Standard electromagnetic fields are generated in TEM cells and used to calibrate electrically small antennas

and antenna systems used for electro- magnetic field probes in the fre- quency range 10 kHz to 300 MHz.

Special-Test Service for Antennas/

Field Strength Measurements,

Utilizing the Open-Field Method

(64200S)

These measurements include calibration of antenna factor and gain of an- tennas used in conjunction with field strength meters, and of electrically

small antennas used in electromagnetic field probes. The following

methods and facilities are used for these measurements:

A. Dipoles, log-periodic, and

other antennas (25 to 1000 MHz) are used to generate electromagnetic

fields which are used for calibrating

various antennas and electromagnetic

field probes. The field strength is es- tablished using the standard receiving

antenna method.

B. Monopoles (30 kHz to 300

MHz) are used to generate standard

electric fields for calibrating antennas

and electromagnetic field probes.

C. Loop antennas (14 kHz to 50

MHz) are used to generate standard

magnetic fields for calibrating loop

antennas used in conjunction with

field strength meters.

Special-Test Service for Antennas/

Field Strength Measurements,

Utilizing the Anechoic-Chamber

Method (64300S)

A. Open-end waveguides (200 to 450 MHz) are used to generate stan- dard electromagnetic fields for cali- brating antennas and electromagnetic

field probes.

B. Pyramidal horns (0.45 to 40

GHz) are used to generate standard

electromagnetic fields for calibrating

antennas and electromagnetic field probes.

Table 22 summarizes the field parameters, frequency ranges, and ra- diating antenna sources for the vari- ous NIST field strength measurement

facilities.

182
64100S-64300S

Table 22: Summary of NIST Standard

Field Strength Facilities

TvDe of Rnflisilinp Field IVIefl su1*6 in cnt Krc(|ucncy Antpnnn

r aralllclcr r uciiiij H Wood 14 kHz to Loop (20 cm)

building 50 MHz

E (vertical) Open site 30 kHz to Short (ground

screen) 30 MHz monopole

E (vertical) Open site 30 to Quarter wave

(ground screen) 300 MHz length

monopole

E (horizontal) Open site 25 to Dipole, log- 1000 MHz periodic

antenna, etc. E and H TEM cell 10 kHz to 300 MHz

Power Density Anechoic 200 to Open-end

chamber 450 MHz waveguide

Power Density Anechoic 0.45 to Pyramidal

chamber 40 GHz horn

References — Electromagnetic Field

Strength Parameter Measurements

Methodology for Standard Electromagnetic Field Measurements,

N. S. Nahman, M. Kanda, E. B. Larsen, and M. L. Crawford, IEEE

Trans. lustrum. Meas.,

IM-34, 4 (Dec. 1985).

A Review of Electromagnetic Compatibility/Interference Measurement

Methodologies, M. T. Ma,

M. Kanda, M. L. Crawford, and E. B. Larsen, Proc. IEEE, 73, 3, 388

(Mar. 1985).

183
65100S-65400S

J.

Pulse Waveform Measurements

Technical Contacts:

William L. Cans

Tel: 303/497-3538 William A. Kissick

Tel: 303/487-3339

S. Michelle Chesnut

Tel: 303/497-3456

Kathy Hillen Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 813.10, National Institute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Test No. Items 65100S

65200S

65300S

65301S

65400S

Impulse Generator Spectrum Amplitude (50 Ohm)

Fast Repetitive Broadband Pulse Parameters

(50 Ohm)

Network Impulse Response (Frequency Domain

Parameter S21) of Coaxial Networks, 10 MHz to 10.0 GHz, 0 to ±40 dB

Additional 65300S Item Tested at Same Time as First Pulse Time Delay through Coaxial Transmission

Lines

Pulse Waveform Measurements —

General Information

NIST offers special-test services for a number of baseband pulse parameters. These are broken down into four

categories: impulse generator spec- trum amplitude, fast repetitive baseband pulse parameters, network

impulse response, and pulse time delay. All of these special-test services are performed on the NIST Automatic Wave Analysis and Measurement System (AWAMS), which

consists of a sampling oscilloscope in- terfaced to a minicomputer. In addition, all of these special tests are performed at cost. References pertaining to these four services are lo- cated at the end of this section.

Impulse Generator Spectrum

Amplitude, 50 Ohms (65100S)

In response to calibration needs from

the electromagnetic interference

(EMI) community, NIST has developed a special-test service to calibrate

the broadband spectrum amplitude

output from impulse generators. Such

a generator can then be used as a

transfer standard of broadband impulsive noise for field calibration of

spectrum analyzers and field intensity meters. The NIST special-test service uses the time-domain measurement/

frequency-domain deconvolution

computational method for calibration

of impulse generators. A wideband

(dc-20 GHz) sampling oscilloscope

is used to measure the time-domain

waveform from the impulse generator. A dedicated minicomputer then

computes the spectrum amplitude,

S(f), versus frequency using the fast Fourier transform (FFT). NIST will provide 50 to 200 data points over a wide frequency range for a single fee. NIST impulse generator spectrum

amplitude measurement service capabilities are shown in Table 23.

Electrical Pulse Inputs

t I

Operator Minicomputer

System -^Output

Waveforms

Correl, Funct. Complex Spectra

t \

Optical Pulse Inputs

184
Table 23: NIST Impulse Generator Spectrum Amplitude

Measurement Service Capabilities

Parameter Limits Notes

Maximum impulse

amplitude without

attenuators ± 600 mV 1, 2, 3 Maximum impulse

amplitude with

external attenuators ±1.2 kV 3,4

Spectrum amplitude -15 dB|jLV/MHz < [S(f) -So]< +5 dBpiV/MHz

5, 6, 7

S(f) uncertainty Nominally f < 1 GHz,

±0.6 dB

1 GHz<f<4 GHz,

± 1.2 dB

4 GHz<f<10 GHz,

±2.0 dB

5,

6,7

8 & 9 Frequency range GHz

5 MHz to 10

5 6 7 & 10 Frequency spacing Af=5, 10,20, 50, or 100 MHz 5, 10 Frequency uncertainty of the order of ± 1% 7 Load impedance 50.0 fl Load impedance

uncertainty

Nominally ±0.1 fi at dc

VSWR < 1.3 up to 10 GHz

8,11

Trigger pulse

amplitude

>100 mV 12

Trigger pulse

transition duration <5 ns 12

Trigger to impulse

delay 75 ns<ti<100 ns 12

Trigger to impulse

jitter <20 ps 12

Notes: 1. The impulse generator is characterized by its impulse output waveform into 50 ohms of peak amplitude (Vp^), 50 percent level duration (t), and low-frequency spectrum amplitude (Su = 2VpkT).

2. Impulse generator with an adjustable amplitude impulse out- put will be calibrated with the generator adjusted to give a peak ampli- tude in the range of 200 to 400 mV.

3. Impulse generators with fixed outputs greater than ±400mV

must have the impulse attenuated to the 200-400 mV level by 50-ohm

wideband coaxial attenuators.

4. Either customer-supplied or NIST attenuators may be used.

5. Depends upon actual generator characteristics.

6. Data will not be given in the first spectrum null or at fre- quencies above. Typically 100 data points are supplied.

7. Subject to revision.

8. Only for impulse amplitudes less than ±400 mV.

9. If external attenuators and/or a 6-dB tee and delay line are used, then the uncertainty associated with the attenuator calibration is added to these values.

10. Lower frequencies (<5 MHz) are available as a special test. 11. Depends up)on input impedance of external attenuators when used.

12. If the impulse generator does not supply a trigger output or

if the trigger output does not have the proper characteristics, then a 6-dB

tee and a delay line will be used to provide a suitable trigger pulse.

65100S-65400S

Fast Repetitive Baseband Pulse

Parameters, 50 Ohms (65200S)

NIST offers a special-test service for selected pulse parameters. These

parameters are measured with the

NIST Automatic Wave Analysis and

Measurement System (AWAMS),

which consists of a calibrated wideband (nominally dc-20 GHz) equivalent-time sampling oscilloscope

custom interfaced to a dedicated

minicomputer system. The parameters, ranges, and estimated uncertainty limits for this service are listed

in Table 24.

Table 24: Limits of Uncertainty for Calibration of Fast Repetitive Baseband Pulse Parameters

Typical

Limits of Parameter Range Uncertainty*

Pulse Baseline (0% level) ± 500 mV (0 5% -1-1 mV)

Pulse Topline (100% level) ± 500 mV (0 5% -hi mV)

Pulse Amplitude ±500 mV (0 5% + 1 mV)

Pulse Overshoot/ ±500 mV (0 5% -1-1 mV)

Undershoot

Pulse First Transition Duration (Rise Time) 10 ps-100 ns (0 5% -1-2 ps) Pulse Second Transition Duration (Fall Time) 10 ps-100 ns (0 5% + 2 ps) Pulse Duration (between

50% levels) 10 ps-100 ns (0 5% + 2 ps)

* Smaller limits of uncertainty are achievable in some cases.

185
Restrictions:

1. Customer's device must generate

a repetitive pulse with repetition

rate between 100 Hz and 1 GHz.

2. Customer's device must have a 50-ohms nominal output

impedance.

3. Customer's device should have a precision coaxial output connector, e.g., SMA, APC-7, Type

"N," APC-3.5, etc.

4. Pulse topline is only measured

for "step-like" pulses.

5. Pulse second transition duration

and pulse duration are only

measured for "impulse-like"

pulses.

6. Pulse overshoot/undershoot is estimated as a percent of pulse

amplitude.

This measurement service includes

the previously offered measurement

service referred to in prior editions of

the SP250 Appendix as "Low-Pass

Filter Transition Duration."

Measurements of other pulse

parameters or parameter ranges may

be provided by special arrangement.

Consulting and advisory services also are available.

Network Impulse Response (65300S)

A network time-domain impulse re- sponse measurement service for coaxial networks is offered at NIST. The

resulting data are in the form of a

discrete waveform vector, normally

1024 points in length, with a time

window range of from 2 ns to 100 ns. Also, using discrete Fourier trans- forms, the associated frequencydomain data (S2i[f]) are provided

over a frequency range of 10 MHz to 10 GHz and a gain or loss range of 0

to 40 dB.

These measurements are accomplished by use of the NIST Automatic

Wave Analysis and Measurement

System, which consists of a fast transition duration pulse generator, a

17.5-ps, 50-ohm sampling oscilloscope

and a minicomputer. Two waveforms

are measured, one with the pulse

generator connected directly to the

oscilloscope, and the other with the

unknown network inserted between

the generator and the oscilloscope.

The time-domain impulse response

function and/or the frequency domain

scattering parameter, S2i(f), are then

calculated using an NIST-developed

deconvolution algorithm. A wide vari- ety of connectors can be accommodated. The approximate limits of

uncertainty are less than ± 2 percent

for all parameters.

This measurement service includes

the previously offered measurement

service referred to in prior editions of

SP250 as "Wideband Attenuation or Gain of Coaxial Networks."

Pulse Time Delay through Coaxial

Transmission Lines (65400S)

NIST offers a special-test service for pulse time delay using the same

measurement system described in item 65300S above. The pulse time

delay is measured in the range of 100

ps-100 ns with typical limits of uncertainty of ±{0.5% + 2 ps). Smaller limits of uncertainty are achievable in some cases. Restrictions:

1. Customer's device must utilize precision coaxial connectors for both delay ports.

2. Customer should provide driving

pulse generator if possible. First transition duration (rise time) of

driving pulse generator should

not exceed 10 percent of pulse

time delay to be measured.

3. Customer's device should have

nominal input and output

impedances of 50 ohms.

Measurements for other ranges and

configurations may be made by special arrangement. Consulting and advisory services are available.

186
651008;-65400S

References — Pulse Waveform

Measurements

Calibration and Error Analysis of a Picosecond Pulse Waveform Measurement System at NBS, W. L. Cans, Proc. of the IEEE, Vol. 74,

No. 1, 86 (Jan. 1986).

The Measurement and Deconvolution

of Time Jitter in Equivalent-Time

Waveform Samplers, W. L. Cans,

IEEE Trans. Instrum. Meas.,

IM-32, 1, 126 (March 1983).

Deconvolution of Time Domain

Waveforms in the Presence of

Noise, N. S. Nahman and M. E. Guillaume, Natl. Bur. Stand.

(U.S.), Tech. Note 1047 (Oct.

1981).

Modeling of the Feed-through Wideband (dc to 12.4 GHz) Sampling

Head, S. M. Riad and N. S. Nahman, Digest, 1978 lEEE-MTTS Intl. Microwave Symp., Ottawa,

Canada (June 1978).

Spectrum Amplitude Definition, Generation, and Measurement, J. R. Andrews and M. G. Arthur, Natl. Bur. Stand. (U.S.), Tech. Note 699

(Oct. 1977).

IEEE Standard Pulse Terms and

Definitions, IEEE Std. 194-1977;

and IEEE Standard on Pulse Measurement and Analysis by Objective Techniques, IEEE Std. 181-1977, Inst. Electrical and Electronic Engrs., New York, NY (July

1977).

Impulse Generator Spectrum Amplitude Measurement Techniques,

J. R. Andrews, IEEE Trans. In- strum. Meas., IM-25, 4, 280 (Dec.

1976). Present Capabilities of the NBS Automatic Pulse Measurement System, W. L. Gans, IEEE Trans.

Instrum. Meas., IM-25, 384 (Dec.

1976).

Time Domain Automatic Network

Analyzer for Measurement of RF

and Microwave Components,

W. L. Gans and J. R. Andrews,

Natl. Bur. Stand. (U.S.), Tech.

Note 672 (Sept. 1975).

Pulsed Wavemeter Timing Reference

for Sampling Oscilloscope Calibration, J. R. Andrews and W. L. Gans, IEEE Trans. Instrum. Meas., IM-24, 82 (Mar. 1975).

Pulse Techniques and Apparatus,

Part 1: Pulse Terms and Definitions; Part 2: Pulse Measurements

and Analysis, General Considerations, lEC Publications 469-1 and

469-2, Intl. Electrotech. Com.

(lEC), Geneva, Switzerland (1974).

187
Chapter

Time and Frequency Dissemination

Q Oscillator Characterization
Time and Frequency Measurements

Time and Frequency Dissemination

Technical Contacts:

George Kamas David W. Allan Kathy Ilillen (Frequency) (Time) Administrative

Tel: 303/497-3378 Tel: 303/497-5637 and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 847.40, National Bureau of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Shipping Address: M.C. 847.40, Room 4039, National

Institute of Standards and Technology, 325 Broadway,

Boulder, CO 80303-3328

Test No. Items 76100S Special Tests of Time and Frequency; Frequency

Measurement Service (Frequency delivered to user's

site) 761 lOS Special Tests of Time and Frequency; Global Time

Service (Frequency and Time delivered to user's site)

NIST Broadcast of Time and

Frequency Signals (No Test No.)

NIST offers several continuous time

and frequency dissemination services that are freely available to the general public. These services are pro- vided via the radio broadcasts of

stations WWV, WWVH, and WWVB,

and a time-code disseminated from

the GOES satellites. WWV's signal is also available by

dialing (303) 499-7111. A similar ser- vice from WWVH is available by

dialing (808) 335-4363. (These numbers are not toll free.)

Broadcasts from WWV (Fort

Collins, Colorado) and WWVH

(Kauai, Hawaii) can be received on

conventional shortwave receivers

nearly anywhere in the world. Broadcast frequencies are 2.5, 5, 10, and 15 MHz for both stations and 20 MHz

for WWV only. Accuracies of 1 to 10

milliseconds in time and 1 x 10"* in frequency are typical from these

broadcasts. These stations provide

standard frequencies, standard time

intervals, time-of-day announcements,

a binary-coded-decimal (BCD) time

code, astronomical time corrections,

and certain public service announce- ments for other government agencies.

For individuals without receivers, the

telephone service provides the same NIST time and frequency signals. The

time signal by telephone is accurate

to only 30 milliseconds or better due

to unpredictable delays in cross-country telephone line routings.

WWVB (Fort Collins, Colorado)

offers accuracies of 0.5 millisecond in time and 1 x 10"" in frequency but

requires a special 60-KHz lowfrequency receiver. WWVB's timecode signal is a BCD type needing

special decoding equipment. The

GOES satellites broadcast an NIST

time code accurate to 100 microseconds to the western hemisphere.

These are geostationary weather

satellites located at nominally 75° west and 135° west longitude.

NIST broadcast services are coordinated with similar operations in other

countries. Commercial receivers designed to receive (and decode) NIST

broadcasts are available from several manufacturers. A number of publications are available to assist users to record properly the time and fre- quency information available from

these broadcast services.

189
Special Frequency Measurement

Service (76100S)

Frequency calibration requirements at the part in 10" to a part in 10'^ level can be satisfied using low-frequency

radio signals from broadcast stations

such as WWVB or Loran-C. This ser- vice involves a low-frequency receiver

and data logger system at the user's

site. The typical system contains a re- ceiver, microcomputer, disc units, and

printer-plotter. A dedicated phone

line and modem must be provided by

the user so that his data can be compared with that obtained at NIST,

thus providing measurement assur- ance. The user will also receive a bulletin, either by telephone transfer or by mail, which reports the perfor- mance of many of the accurate signal sources accessible by the system. To

assist the user in getting the maximum benefit from the service, NIST

provides specific training on the ac- tual equipment.

Special Global Time Service (761 lOS)

This service uses the Global Positioning System (GPS) satellites compatible with the common-view technique

receiver, which provides much higher

precision time and frequency data

and a high degree of automation. The

data from a receiver, which is located

at the user's facility, are automatically

sent to a NIST computer. The NIST

computer then stores the raw data,

determines which data are suitable

for time transfer calculations, and

provides an optimally filtered value

for the time and frequency of the

user's clock with respect to the NIST

atomic time scale. The results are communicated to the user in a monthly report. The user is also given an account on one of the NIST

computers through which he may ac- cess a preliminary NIST analysis,

which is calculated daily. Tests between receivers in California, Colorado, Washington, D.C., France,

Germany, Spain, and Canada have

demonstrated an ability to perform

time comparisons with a precision of

1 X 10"''' or better (la) for averaging

times of 4 days and longer. While

useful characterization of frequency

stability is available to at least this latter level, frequency accuracy is limited to 8x 10"'\ the accuracy of the

NIST primary frequency standard.

References— Time and Frequency

Dissemination

NBS Measurement Services: GOES

Satellite Time Code Dissemination: Description and Operation,

R. E. Beehler, D. Davis, and J. B. Milton, Natl. Bur. Stand. (U.S.),

Spec. Publ. 250-30 (Jan. 1988).

NBS Measurement Services: Traceable Frequency Calibrations,

G. Kamas and M. A. Lx)mbardi,

Natl. Bur. Stand. (U.S.), Spec.

Publ. 250-29 (Jan. 1988).

Accuracy of International Time and

Frequency via Global Positioning

System Satellites in Common View,

D. W. Allan et al., IEEE Trans.

Instrum. and Meas., IM-34, 2, 118

(June 1985).

New Time and Frequency Services at the National Bureau of Standards,

S. R. Stein, G. Kamas, and D. W.

Allan, Proc. 15th Annual Precise

Time and Time Interval (PTTI)

Applications and Planning Meeting, 17 (Dec. 1983).

NBS Time and Frequency Dissemination Services, Natl. Bur. Stand.

(U.S.), Spec. Publ. 432 (Sept.

1979).

190
77100C^77140S

Oscillator Characterization

Technical Contacts:

James E. Gray Kathy Hillen

Tel: 303/497-3209 Administrative and Logistics

Tel: 303/497-3753

Mailing Address: M.C. 847.50, National Insitute of

Standards and Technology, 325 Broadway, Boulder, CO

80303-3328

Shipping Address: M.C. 847.50, Room 2019, National

Institute of Standards and Technology, 325 Broadway,

Boulder, CO 80303-3328

Test No. Items 77100C Precision Oscillator Frequency Calibration 77110C Characterization of Atomic Time and Frequency

Standards

77120C Characterization of Precision Oscillators: Time Domain

77130C Characterization of Precision Oscillators: Frequency Domain

77131C Characterization of Precision Oscillators: Frequency Domain, High-Accuracy Option

77140S Special Time/Frequency Measurements:

Oscillators and Other Components

Precision Oscillator Frequency

Calibration (77100C)

Precision oscillators can be readily

calibrated in the frequency range

from 1 to 100 MHz. Reference cali- bration accuracy is nominally that of

the NIST primary frequency standard,

that is, 8x 10~'^ The accuracy level transferable to the oscillator depends

upon the stability and noise properties of the oscillator.

Characterization of Atomic Time and

Frequency Standards (77110C)

An atomic standard is characterized

by introducing it as a member of the

NIST time scale system. The clock

output is sampled every 2 hours in sequence with the other regular

clocks in the time scale. The data are logged in the NIST time scale computer and the characteristics of the

standard are readily determined in relation to the performance of the

time scale ensemble of clocks. The

standard test involves 30 days of data

acquisition. The square root of the

Allan variance, CTy(T), is measured to ±2x 10" '^""^ for averaging times of

about 7200 to 10'' seconds. The time

scale accuracy is about 1 x 10"'^ and

frequency drift is less than one part

in 10'^ per day. The actual values

transferable to the standard depend

on its stability and noise properties.

Characterization of Precision Oscillators: Time Domain (77120C)

For oscillator frequencies of 5, 10,

and 100 MHz, the stability in terms of

ay(T) is determined by repeated measurements. The square root of the

Allan variance, ay(T), is measured to ±2x 10" for averaging times of

1 to approximately 10,000 seconds,

and frequency offset is measured to about 1 X 10" '\ As noted under the

description of tests 77100C and

77 HOC, the transferable accuracy depends upon the stability and noise

properties of the calibrated oscillator.

Characterization of Precision Oscillators: Frequency Domain (77130C)

For oscillator frequencies of 5, 10,

and 100 MHz, phase noise S,j>(f) can be determined for Fourier frequency

offsets from the carrier of 0.1 Hz to 300 kHz (higher by special request).

The phase noise is measured for only

a few user-specified frequency offsets.

191
For an offset of 1 Hz, Si.(f) can be

measured to - 115 dB (relative to 1 radians/Hertz) and for an offset of 10

kHz, S<t,(f) is measured to - 175 dB.

Characterization of Precision

Oscillators: Frequency Domain,

High-Accuracy Option (7713 IC)

For a pair of identical oscillators within a limited range of Fourier off- set frequencies, phase noise, S^({) can be measured with an error not ex- ceeding ± 0.6 dB. For this accuracy, the frequency offset must lie between

20 Hz and 10 kHz. In other respects

this service is the same as 77130C.

Special Time/Frequency Measurements: Oscillators and Other

Components (77140S)

Frequency and time domain measure- ments can be made at frequencies

other than those cited in tests 77120C

and 77130C, but the accuracy and

cost are dependent upon the value of

the frequency. Given two or more oscillators, synthesizers or amplifiers,

relative phase noise can be measured

to a very high precision and the fre- quency for the measurement is not as

restrictive as above. Also, the one PPS (pulse per second) output of

atomic frequency standards can be

measured with an accuracy of 0.5 nanoseconds given an adequately defined, fast pulse.

Reference — Oscillator

Characterization

Properties of Signal Sources and

Measurement Methods, D. A.

Howe, D. W. Allan, and J. A.

Barnes, Proc. 35th Ann. Freq.

Control Symp., A.l, Phil. (May

1981).

192
ALPHABETICAL CROSS-INDEX

Item Test Number

Absolute pressure transducers 30010C-30011C

Accelerometers 24010C-24060S

Ac-dc thermal converters (100 Hz to 1 GHz) 53405S-53445S

Ac-dc thermal converters (to 1 MHz) 53310S-53341C

Ac-dc watthour or varhour meters 56110S-56210M

Ac resistors 51410S

Ac voltage, high-accuracy 53200S-53201S

Acoustic devices 25060S

Acoustic emission transducers and sensors 26200C-26210S

Acoustic measurements 25010C-25070S

Activation detector dosimetry 44070C-44090C

A/D or D/A data converters 53500S-53540S

Air navigation aids 55210S-55230S

Airspeed measurements 19010C-19040S

Alpha-particle-emitting solid sources 43030C-43050C

Aluminum ultrasound reference blocks 26030S,26050S,

26070S

American Petroleum Institute gages 12010C

Analog-to-digital data converters 53500S-53540S

Anemometers 19010C-19040S

Angle gage blocks. 14010C

Angular measurements 14010C-14050S

Antenna parameter measurements, microwave. 63100S-63400S

Attenuators, rf and microwave. 61210S-61250S

Audiofrequency phase meter 55120C-55141C

Balls 11030S

Barometers 29035C,

30010C-30011C

Bearing-angle indicators 55210C-55221C

Beckmann thermometers 31080C

Beta particle applications 47030C-47040S

Beta-particle-emitting sources 43060S-43070S,

47030C-47040S

Bolometer units, rf and microwave 61110S-61129S

Calorimetric thermometers 31070C

Capacitance and inductance measurements, high-frequency 52210S-52310S

Capacitance and inductance measurements, low-frequency 52110S-52181C

Capacitive voltage dividers 54310S-54311S

Capacitors, dielectric 52130C

Capacitors, high-frequency 52210S-52221S

Capacitors, low-frequency 52110S-52171C

Capacitors, power-frequency 52400C

Coaxial air line standards 61510S

Coaxial attenuators 61210S-61211C

193
Coaxial terminations and reflection coefficients 61310S-61340S

Coaxial thermistor mounts 61110S-61129S

Color temperature 37140C-37160C

Complex dimensional standards 12010C-12040S

Converters, A/D and D/A 53500S-53540S

Cryogenic flow measurements 18800S

Current and voltage transformers 54510C-54600S

Data converters, A/D and D/A 53500S~53540S

Dc resistance measurements 51100S-51163C

Dc voltage measurements 53110S-53190S

Deadweight piston gages 29010C

Deadweight tester, ball-type 30025C

Density measurements, liquids 17040S

Detector standards, windowed photodiode 40560C-40561C

Detector standards, windowless photodiode 40510C-40540C

Detectors, near ultraviolet to sofl x-ray region 40599S

Deuterium arc lamps 40030C

Deuterium lamps 39050C

Dew-point hygrometers 36010C-36020C

Diameter measurements 11010S-11070S

Dielectric materials 61620S

Differential pressure transducers 30020C-30021C

Digital multimeters, low-frequency 53200S

Digital-to-analog data converters 53500S-53540S

Dimensional metrology 10010C-14050S

Dividers, capacitive 54310S-54311S

Dividers, inductive 54110S-54131C

Dividers, mixed 54410S

Dividers, resistive 54210C-54214S

Dosimeters, electron-beam 48010M-48020S

Dosimeters, high-dose 49010C-^9050S

Dosimeters, neutron 44100S

Dosimeters, radiochromic 49010C-49030C

Dosimeters, spectrophotometric reading 49040S-49041S

Dosimeters, x-ray, gamma-ray, and electron 46010C-48020S

Dosimetry, neutron 44010C-44100S

Earphones 25070S

Electromagnetic field strength parameter measurements 64100S-64300S

Electrometers 46030S

Electron beam dosimetry 48010M-48020S

Energy and power measurements, low frequency 56110S-56210M

Ferrous-ferric dosimeters , 48010M-48011M

Field strength measurements, electromagnetic 64100S-64300S

Filament lamps, ribbon 35050C-35060C,

39010C-39020C

Filters, spectral transmittance 38010C-38040C

Fixed-point devices, thermometric 33360S

Flats, optical reference 13010S

194
Flow measurements, cryogenic 18800S

Flow rate meters, liquid and gas 18010C-18050S

Flux standards, luminous 37080S

Force transducers 23010C-23260S

Frequency and time measurement services 76100S-76110S

Frequency domain 77131

C

Gage blocks 100 IOC

Gages, API 12010C

Gages, ionization 30034C-30038C

Gages, low-pressure 30040S

Gages, molecular drag 30029C-30031C

Gages, piston 29010C-29020C

Gages, plug IIOIOS

Gages, plug and ring 12020S

Gages, pressure 29010C-29040S

Gages, ring 11040S

Gages, step 11060S

Gages, two-dimensional 12030S

Gages, vacuum 30010C-30050S

Gamma-ray dosimeters 46010C-46021C

Gamma-ray-emitting sources 43010C-43020C,

47010C-47011C

Gas flow meters 18050S

Gear measuring wires 11020C

Germanium resistance thermometers 33140C

Global time service 761 lOS

Heat flux gauges 3651 OS

High-dose dosimetry 49010C-49050S

High-frequency standard capacitors and inductors 52210S-52221S

High-frequency standard resistors 5 131 OS

High-vacuum gages 30029C-30038C

High-voltage resistors 51210C

Humidity measurements 36010C-36070S

Hydrometers 160 IOC

Hygrometers 36010C-36070S

Impedance measurements 5211 OS

Impulse generator spectrum amplitude 65100S

Impulse response of coaxial networks 65300S

Indexing tables 14030S

Inductance and capacitance measurements, low-frequency 52110S-52150C

Inductance and capacitance measurements, high-frequency 52210S-52310S

Inductive voltage dividers 54110S-54131C

Intensity standards, luminous 37015C-37035C

Internal diameter standards 11040S

Ionization chambers 47036C

Ionization gages 30034C-30038C

Irradiance sources 39040C-39050C,

40010C,40030C

195
Kerr cells 54410S

Laboratory thermometers 31010C-31160S

Lamps, deuterium arc 39050C, 40030C

Lamps, incandescent 37015C-37140C

Lamps, quartz-halogen 39040C-39045C

Lamps, ribbon filament 35050C-35060C,

39010C-39030C

Laser frequency/wavelength 14510S

Laser power and energy measurements 42110C-42170S

Leak artifacts 30060S

Length and diameter 11050S

Length measurements 10010C-10060S

Length standards 10050S

Line standards 10020C

Liquid flow meters 18010C-18050S

Liquid-in-glass thermometers 31010C-31160S

Load cells 23010C-23260S

Luminous directional transmittance standards 37170C

Luminous flux 37080S

Luminous intensity 37015C-37035C

Luminous intensity of retroreflectors 38070M

Luminous transmittance standards 37170C

Manometers 29035C

Mass measurements 22010C-22180M

MEASUREMENT ASSURANCE PROGRAMS

Dc resistance 511 lOM

Dc voltage 53120M

Dose interpretation of ferrous-ferric dosimeters 48010M^8011M

Laser power and energy 42120M,42140M,

42150M

Mass 22180M

Platinum resistance thermometry 33370M-33390M

Retroreflectance 38070M-38074M

Transmittance 38080M

Watthour meters 56210M

Mercurial Barometer and Manometers 29035C

Meteorological airspeed instrumentation 19030S

Meters, flow rate 18030C

Meters, laser power and energy 421 IOC, 42170S

Meters, optical fiber power 42130C, 42140M,

421 80S

Meters, phase 55110S-55141C

Meters, turbine 18010C-18020C

Microcopy resolution test charts 38100S

Microphones, pressure and free-field response 25010C-25050C

Micropotentiometers, low voltage 53201S

196
Micropotentiometers, rf 53440S-53445S

Microwave antenna parameter measurements 63100S-63400S

Mixed voltage dividers 5441 OS

Molecular drag gages 30029C-30031C

Neutron dosimeters 44100S

Neutron sources 44010C^4020C

Noise temperature measurements, coaxial and waveguide 62020S-62133S

Oil gaging and surveying tapes 10030C

Opal glass transmittance standard 37170C

Optical fiber power meters 42130C-42140M,

421 SOS

Optical flats 13010S

Optical polygons 14020S

Optical pyrometers 35010C-35040C

Optical reference planes 13010S

Oscillator characterization 77100C-77140S

Penetrameters, x-ray 46040S

Personnel protection instrumentation 44060C

Phase measurements 55110S-55141S

Phase shifters, rf and microwave 61410S-61450S

Photodiode spectral response 39070C

Photodiodes, windowed and windowless 40510C-40560C

Photographic step tablets 38090S

Photometric tests 37180S

Photometry 37015C-37180S

Pickup sensitivity 24010C-24030C,

24050C

Piston gages, controlled clearance 29020C

Piston gages, deadweight 29010C

Pitot-static tubes 19010C

Platinum resistance thermometers 33010C-33310C

Plug and ring gages 12010C-12020C

Plug gages IIOIOS

Pneumatic bridge hygrometers 36060C

Polygons, optical 14020S

Power and energy measurements, low-frequency 56110S-56210M

Power meters, optical fiber 42130C-42140M,

42180S

Pressure gages and transducers 29030C

Pressure gages, low absolute 30010C-30011C

Pressure gages, low differential 30020C-30021C

Pressure gages, special tests 29040S

Pressure measurements 29010C-29040S,

30010C-30060S

Proving rings 23010C-23260S

Pulse voltage measuring systems 54410S

Pulse waveform measurements 65100S-65400S

Pyrometer indicators 32100C

197
Pyrometers, optical 35010C-35040C

Pyrometers, radiation 35070S

0-standards 52710C-52711C

Quartz-halogen lamps 39040C-39045C

Radiance standard sources 39010C-39030C,

40020C

Radiant energy detectors 39070C

Radiation detectors 46010C-46011C

Radiation pyrometers 35070S

Radiation thermometry 35010C-35070S

Radioactive sources, alpha-emitting 43030C^3050C,

43090S

Radioactive sources, beta-emitting 43060S^3070S

Radioactive sources, gamma-emitting 43010C-43020C

Radioactive sources, neutron-emitting 44010C-44020C

Radiochrometric dosimeters 49020C-49030C

Radiometric detectors, special tests 39080S

Radiometric measurements 39010C-39080S,

40010C-40040S,

40510C-40599S

Radiometric sources 39060S

Radionuclides 43010C-43090S

Reference block measurements, ultrasonic 26030S-26070S

Reflection coefficients, coaxial and waveguide terminals 61310S-61340S

Resistance measurements, dc 51100S-51163C

Resistance thermometers 33010C-33310S

Resistive voltage dividers 54210C-54214S

Resistors, ac 51410S

Resistors, high-frequency 51310S

Resistors, high-precision standard, dc 51130C-51154C

Resistors, high-voltage 51210C

Resistors, megohm 51142C-51150C

Resistors for current measurements 51160C-51163C

Retroreflectors, coefficient of luminous intensity 38070M-38074M

Ribbon filament lamps 35050C-35060C

Ring gages 11040S

R-meters 46010C-46011C

Rods, surveying leveling 10040S

Rotary and indexing tables 14030S

Roughness specimens 15010C-15020C

Roundness measurements 13020S-13030S

Saturated standard cells 53130C-53131C

Shock measurements 24040S

Sieves 10060S

Spectral irradiance 39040C-39050C,

40010C,40030C

Spectral irradiance, lamps 39040C-39050C

198
Spectral radiance 39010C-39030C,

40020S

Spectral radiance, lamps 39010C-39030C

Spectral response, photodiode 39070C

Spectral transmittance filters 38010C-38040C,

Spectrophotometric measurements 38010C-38100S

Spherical diameter standards, balls 11030S

Standard voltage cells 53130C-53150C

Steel ultrasound reference blocks 26040S,26060S,

26070S

Step gages, length 11060S

Step height measurements 15030C

Step tablet density, photographic 38090S

Surface roughness standards 15020C

Surveying and oil gaging tapes 10030C

Surveying leveling rods 10040S

Thermal voltage and current converters (100 Hz-1 GHz) 53405S-53445S

Thermal voltage converters (to 1 MHz) 53310S-53341C

Thermocouples and thermocouple materials 32010C-32150S

Thermometers, Beckmann 31080C

Thermometers, calorimetric 31070C

Thermometers, cryogenic 33140S

Thermometers, germanium resistance 33140S

Thermometers, laboratory 31010C-31260S

Thermometers, platinum resistance 33010C-33310C

Thermometric fixed-point devices 33360S

Thermometry, radiation 35010C-35070S

Thread measuring wires 11020C

Threaded plug and ring gages 12020S

Time and frequency measurement services 76100S-76110S

Time domain 77120C

Titanium ultrasound reference blocks 26040S,26060S,

26070S

Transducer measurements, acoustic emission 26200C-26210S

Transducer measurements, ultrasonic 26100C-26120S

Transducers, low-pressure 30010C-30021C

Transformers, voltage and current 54510C-54600S

Transmittance, luminous directional 37170C

Transmittance, Measurement Assurance Program 38080M

Transmittance filters, spectral 38010C-38040C

Turbine flow meters 18010C-18020C

Ultrasonic reference block measurements 26030S-26080S

Ultrasonic system power, calorimetric 261 IOC

Ultrasonic transducer measurements 26100C-26120S

Ultrasonic transducer power, radiation pressure 26100C

Ultraviolet detectors 40510C-40599S

Ultraviolet sources 40010C-^0040S

Unsaturated standard cells 53150C

199
Vacuum gages 30029C-30038C,

30050S

Vacuum measurements 30010C-30050S

Vacuum ultraviolet radiometric measurements 40010C-40040S

Var, varhour meters 56200C-56202C

Velocity reference blocks 26080S

Very-high-frequency omnidirectional range (VOR) measurements 55210C-55230S

Vibration and shock measurements 24010C-24060S

Voltage, ac 53201S

Voltage, dc 53110S-53190S

Voltage, rf-dc 53405S-53445S

Voltage and current transformers 54510C-54600S

Voltage dividers, capacitive 54310S-54311S

Voltage dividers, inductive 54110S-54131C

Voltage dividers, mixed 54410S

Voltage dividers, resistive 54210C-54214S

Voltage reference standards, solid state 53160C-53161C

Voltmeters, high-accuracy, ac 53200S

Volume standards 17010C-17020S

VOR measurements 55210C-55230S

Watt, watthour meters 56110S-56210M

Waveform measurements, pulse 65100S-65400S

Waveguide attenuators 61230S

Waveguide terminations and reflection coefficients 61320S-61340S

Waveguide thermistor mounts 61144S-61155S

Wavelength standards 38050C

Wedges 14040S

Weights (mass standards) 22010C-22180M

Wires for thread and gear measurements 11020C

X-ray and photographic step tablets 38090S

X-ray dosimeters 46010C-46050S

X-ray penetrameters 46040S

200
At $23.00 A Year , Can You Afford Not To

Know What's Going On At The Nation's

Measurement Science Laboratory?

The Journal of Research Brings You

Up-to-Date Scientific Articles and

Information on:

• Measurement Science and Technology

• Calibration Services

• Standard Reference Materials

• Cooperative Research Opportunities and Grants

• Conference Reports

AND MUCH MORE!

It's All At Your Fingertips In the Journal of Research of the

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

Subscribe Today !

Journal of

Research of the

National

Institute of

Standards and

Technology

Superintendent of Documents Subscription Order Form

YES, send me subscriptions

to the JOURNAL OF RESEARCH OF THE

NATIONAL INSTITUTE OF STANDARDS

AND TECHNOLOGY at $23 per subscription (6 times a year) so I can stay up to date on the latest developments in measurement

science and technology.

Order Processing Code 6596

1. Please Type or Print

(Company or personal name)

(Additional address/attention line)

(Street address)

(City, State, ZIP Code)

( ) (Daytime phone including area code) 4. MAIL TO: Superintendent of Documents, Washington, DC 20402-9371. Kindly return

2. The total cost of my order is $ . All prices include domestic postage and handling. International customers please add 25 percent.

3. PLEASE CHOOSE METHOD OF PAYMENT:

Check made out to the Superintendent of Documents GPO Deposit Account aVISA, or MasterCard

Thank you for your order!

(Credit Card Expiration Date)

(Signature) (2/89)

this card even if you use your organization's purchase order. Thank you.

>

II ; j .