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The National Measurement System for Radiometry and Photometry

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The National Measurement System for Radiometry and Photometry NATL INST jjlllllll A11107 QSfl07Q PUBLICATIONS NBSIR 75-939 The National Measurement System for Radiometry and Photometry H. J. Kostkowski Institute for Basic Standards National Bureau of Standards Washington. D C. 20234 November 1977 Final \ 5 loo J.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS NBSIR 75-939 THE NATIONAL MEASUREMENT SYSTEM FOR RADIOMETRY AND PHOTOMETRY H. J. Kostkowski Institute for Basic Standards National Bureau of Standards Washington, D C. 20234 November 1977 Final U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary Dr. Sidney Harman, Under Secretary Jordan J. Baruch, Assistant Secretary for Science and Technology NATIONAL BUREAU OF STANDARDS. Ernest Ambler. Acting Director CONTENTS EXECUTIVE SUMMARY 1 1. INTRODUCTION 3 2. STRUCTURE OF THE MEASUREMENT SYSTEM 3 2.1 Conceptual System 3 2.2 Basic Technical Infrastructure 5 2.2.1 Documentary Specification System 5 2.2.1.1 Standardization Institutions 5 2.2.1.2 Survey of Documentary Standards 6 2.2.2 Instrumentation System 6 2.2.2.1 Measurement Tools and Techniques 6 2.2.2.2 The Instrumentation Industry 7 2.2.3 Reference Data 7 2.2.4 Reference Materials 7 2.2.5 Science and People 7 2.3 Reference Data 8 2.4 Dissemination and Enforcement Network 8 2.4.1 Central Standards Authorities 8 2.4.2 State and Local Office of Weights and Measures 8 2.4.3 Standards and Testing Laboratories and Services 8 2.4.4 Regulatory Agencies 8 2.5 Organizational Input-Output Transactions Matrix 8 2.5.1 Analysis of Suppliers and Users 8 2.5.2 Highlights of Transaction Matrix 9 3. IMPACT, STATUS AND TRENDS OF MEASUREMENT SYSTEM 11 3.1 Impact of Measurements 11 3.1.1 Functional, Technological, and Scientific Applications .... 11 3.1.2 Economic Impacts -- Costs and Benefits 12 3.1.3 Social, Human, Man-on-the-Street Impacts 13 3.2 Status and Trends of the System 14 4. SURVEY OF NBS SERVICES 14 4.1 The Past 14 4.2 The Present -- Scope of NBS Services 15 4.2.1 Description of NBS Services and Program 15 4.2.2 Users of NBS Services 16 4.2.3 Alternate Sources 16 4.2.4 Funding Sources for NBS Services 16 4.2.5 Mechanism for Supplying Services 16 4.3 Impact of NBS Services 17 4.3.1 Economic Impact of Major User Classes 17 4.3.2 Technological Impact of Services 17 4.3.3 Pay-off from Changes in NBS Services 18 4.4 Evaluation of NBS Program 19 4.5 Future 19 5. SUMMARY AND CONCLUSIONS 19 APPENDIX A 20 APPENDIX B 26 APPENDIX C 27 REFERENCES 23 i THE NATIONAL MEASUREMENT SYSTEM FOR RADIOMETRY AND PHOTOMETRY Henry J. Kostkowski Optical Physics Division November 1977 EXECUTIVE SUMMARY This National Measurement System Study is time, and the responsivity of most radiom- on the measurement of light. More specifi- eters also varies with these and other cally it is concerned with the measurement parameters, making such measurements a of the energy or power in ultraviolet, difficult, multi-dimensional problem. In visible and infrared radiation. addition, most of the people needing radiom- The study was undertaken to determine the etry have not been trained in the field. importance of such measurements in the U.S., There are relatively few experts available. the accuracy and ease with which they could As a result of these two factors, measurement be made, the adequacy of this capability, accuracy is poor and large differences in and the nature of the program NBS should measurement are widespread. Much time and pursue in this measurement area. money is spent trying to resolve these In the last ten years, the economic and differences, particularly when mass produced social impact of radiometric and photometric products require components from various measurements has increased significantly. companies and these components must meet Such measurements are required in the man- radiometric or photometric specifications. ufacture of cameras, color TV and copying The cost of inadequate radiometry and machines. Ultraviolet radiation is being photometry is very high. The electro- used extensively for the polymerization of optical industry alone has annual sales industrial coatings. An attempt is being approaching 15 billion dollars per year. A made to use radiometry in measuring atmos- leading instrument manufacturer estimates pheric temperatures for the purpose of that about $200 million is spent each year forecasting weather. New solid-state lamps in calibrating radiometric systems or (LEDs) are used in a variety of visual resolving discrepancies in radiometric displays. Phototherapy is used almost measurements. If better radiometry can exclusively in the treatment of some diseases improve long-term weather forecasting as (e.g. jaundice in the newborn). Regulatory predicted, the economic impact would be agencies are concerned with the hazardous tremendous. It is virtually impossible to effects of UV on the eyes and skin (skin estimate the cost of inadequate radiometry cancer), particularly in industrial environ- relative to medical and safety applications, ments. Dentists are now using a commercially but public health and safety are certainly available "UV gun" for curing various new given a high priority in this country. dental materials. Applications in the lamp Adequate radiometry today means making industry are increasing because of our measurements with a few percent accuracy energy problems. Twenty-five percent of the commonplace. This will require greater U.S. electrical power is used for lighting, expertise in the system and more accurate, and thus, developing lamps that will produce easy-to-use, and less expensive standards the same light for less electrical power has and techniques. a high priority. Improving the utilization NBS has addressed itself to solving of solar energy will require better measure- these problems. It helped organize the ments than are now available. All of these Council for Optical Radiation Measurement uses and applications of light require (CORM), a group largely representing industry radiometry or photometry. Many of them will and providing detailed information and a require a state-of-the-art accuracy of a few consensus of the needs in the system. It per cent in order to achieve their objectives. has worked with the Illuminating Engineering Unfortunately, the current radiometric Society (IES), the Commission Internationale and photometric measurement system is inade- de L'Eclairage (CIE), and the Infrared Infor- quate for the many uses and applications mation Symposia (IRIS). NBS is developing described. Radiometric measurements are more accurate, easy-to-use, less expensive among the most difficult measurements to standards and techniques and is beginning make. The radiant power varies with position, to monitor the capability of the system by direction, wavelength, polarization and inter! aboratory comparisons. It has created specialized publications to insure that all this information is efficiently disseminated. Finally, NBS is also starting to produce a Self-Study Manual for Optical Radiation Measurements. This is expected to signifi- cantly upgrade the level of expertise in the U.S. in this area. In summary, this study has shown that radiometry and photometry are having a significant economic and social impact in the U.S. today and this impact is expected to increase. The capability of this portion of the measurement system is inadequate for today's needs. An accuracy of a few percent is frequently needed; 10-50 percent is commonplace. The reason is that radiometric and photometric measurements are very difficult to make, and there is too little expertise to make these difficult measurements. NBS' program is designed to improve the situation by (1) making the measurements easier through simpler, inexpensive standards and techniques and (2) increasing the expertise through a Self-Study Manual on the subject. 2 1. INTRODUCTION Everyone has his own built-in photom- NBS. During and following the preparation eter -- the eye. The normal eye can see of these reports, a new NBS program in differences in light intensity and color of radiometry and photometry evolved. 1%. Yet the most sophisticated instruments In general, the approach used in con- available today do not measure the absol ute ducting this National Measurement System intensity of light with an accuracy of Study was to try to answer the following better than 1%. Discrepancies of 10" are four questions: common and the 1% accuracy is only realized 1. Why are radiometry and photometry in a few cases and in the best standards important in the U.S. today? laboratories of the world. 2. What is the status of radiometry In spite of this situation, the accuracy and photometry in the U.S.? and efficiency with which radiometry and 3. What is needed? photometry can be performed affects every- 4. How should NBS respond? one in this country. Such measurements are Information was obtained primarily from per- important in sonal discussions and correspondence with - Developing more efficient lamps (one- many concerned individuals in industry and fourth of the electricity used in the government. Extensive interaction with U.S. is for lighting) industry and other government agencies is - Developing the use of solar energy continuing. Conditions and needs change. - Treating various diseases by photo- The NBS program in radiometry and photometry therapy (e.g. jaundice in over 10,000 must be updated to take account of these infants born in the U.S. each year) changes. The current report is a "snapshot", - Specifying and controlling ultra- "taken" in March 1975, of the U.S. National violet radiation hazards (these can Measurement System for Radiometry and cause eye damage and skin cancer) Photo-metry. It is a summary of what we - Pollution monitoring have learned about the System and what we - Weather forecasting are trying to do to improve it. - Automating the production of many manufactured products such as lamps, 2.
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