Measurement Standards and How They Support Society Akira ONO, Research Coordinator 4

The Role of Measurement Standards Units and Measures Hirokazu MATSUMOTO, Deputy Director, Metrology Institute of Japan 4

Measurement Standards for Better Safety and Security Toshihide IHARA, Manager, Metrology Planning Office, Metrology Management Center 4

Optical Comb: A leading-edge technology for optical frequency measurement Hajime INABA, Wavelength Standards Section, Time and Frequency Division, Metrology Institute of Japan 6

Legally Designated Measurements That Protect the Security of Our Everyday Lives Takeshi ITO, Metrology Planning Office, Metrology Management Center 7

Measurement Standards at Production Sites: Automobiles Tomohiro MOCHIZUKI, Measurement Engineering Department, Nissan Motor Co., Ltd. 8

Measurement Standards in Aircraft Maintenance Toshirou ITOU, Quality Assurance Department, Japan Airlines 9

Measuring Gene Quantities Mamoru KAWAHARASAKI, Bio-Medical Standards Section, Organic Analytical Chemistry Division, Metrology Institute of Japan 10

The Development and Spread of Nanotechnology and Related Measurement Standards Toshiyuki FUJIMOTO, Surface and Thin Film Standards Section, Meterials Characterization Division, Metrology Institute of Japan 11

A Young Researcher Offers Her Views Yukiko SHIMIZU, Radiation Thermometry Section, Temperature and Humidity Division, Metrology Institute of Japan 11

Using the Avogadro Constant as a New Standard for Mass Kenichi FUJII, Fluid Properties Section, Material Properties and Metrological Statistics Division, Metrology Institute of Japan 12

Next-Generation Standards for High Temperatures Yoshiro YAMADA, Radiation Thermometry Section, Temperature and Humidity Division, Metrology Institute of Japan 13

Current Status of International Mutual Approval and Future Directions Mitsuru TANAKA, Director, Metrology Institute of Japan 14

The development of measurement standards is one of the most important missions of the National

Institute of Advanced Industrial Science and Technology (AIST), and is expected to show significant growth. As the core organization concerned with measurement standards in Japan, NMIJ conducts various activities both at home and abroad, while integrating the development of measurement standards with other related activities. “The Metrology Institute of Japan (MIJ)” is in charge of research and development. MIJ is structured so that its divisions correspond to the ten Consultative Committees of the

International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM), which was organized according to the Meter Convention, and also has divisions specifically designed for handling legal metrology. Aware of the significance of training measurement experts in order to provide, disseminate, and publicize measurement standards efficiently, the Metrology Management Center has been set up, consisting of the Metrology Planning Office, the Metrology Quality Office, the International Metrology Cooperation Office and the Metrology Training Center. Working closely with one another like a single unit, MIJ and the Metrology Management Center continuously strive to establish, maintain and provide a wide variety of measurement standards for our country.

Measurement Standards and How They Support Society Akira ONO, Research Coordinator Whenever we buy, sell or exchange any kind of item, we use a remarkably broad array of units. Each of these units is determined according to a standard gradation, or measurement standard. Thanks to the existence of these measurement standards, we can carry out an infinite array of activities and transactions with the confidence that we know exactly how much of each item we are dealing in. Mutual Recognition For today’s advanced technologies, such as nanotechnology and biotechnology, ever more precise measurement When countries mutually recognize the equivalence of national measurement standards are required. The importance of such precise measurement is growing constantly. standards to each other, the reliability of measurement exchanged among users How are these measurement standards defined? How are they established and propagated for general use? in different countries will be secured. Consequently, in turn, smoother international trade will be possible. The World of the International System of Units (SI) Japan Calibration of a gauge block length National Standards Laser light using laser equipment m for Length Iodine-stabilized He-Ne m-1 rad laser National measurement standards m2 luminous intensity mass m3 Iodine-stabilized He-Ne lasers = Primary measurement standards N.m lx sr kg T cd provide an extremely stable (established by AIST) kg/m 3 light source at a wavelength of lm m3/kg 633 nm. These lasers can real- Observation N W/sr ize an accurate “ruler” with a Uncertainty Pa J/kg scale division of half the wave- mol/ m3 －11 Sv Gy m/s2 length, using an interferome- 10 m/s ter. They are also used as a Pa.s H/m (precision to 0.1 mm when secondary measurement stand- measuring 10,000 km) A/m 2 J A/m ard. Secondary measurement 3 cd/m 2 kat J/m standards

s W mol Practical Standards (calibrated by AIST) W/m2 H Gauge blocks account for ap- time C Wb amount Bq Hz of substance proximately 80% of the practi- Gauge Block V Traceability J/mo l cal length standards presently J（/ kg.K） in use. A gauge block is one of Calibration of a slide caliper The Dissemination F J（/ mol.K）℃ the end standards in a block using a gauge block J/K shape. The distance between System of Measure- F/m its two ends is used directly as ment Standards A Ω S K a length standard. Because of 10－7 that, there are over a hundred In the pyramid of traceability, electric current thermodynamic temperature of them that are different in (precision to 1 m when the number of standards in- size. Their shapes are main- measuring 10,000 km) creases starting with national Practical standards measurement standards at the All SI units are derived from of the seven basic units. tained by precision polishing (calibrated by accredited and their absolute length can top, moving down to secon- These units are mutually interconnected. For example, laboratories) dary standards, and further the unit of time (s) is necessary to define length. be realized with better than 0.05 m precision. down to working standards.

μ Reversely, working standards

4 3 2 1 0 at the bottom of the pyramid can trace up to a higher level Measuring devices for of standards and eventually general use reach the top of the pyramid, Various kinds of measuring or national measurement devices used for manufactur- standards. ing, such as slide calipers, micrometers and dial gauges, slide caliper are included in this category.

－5 Measuring devices for general use The Role of Measurement * nm (nanometer; 1 nm = 1/100 10 (produced by manufacturers) millionth of a meter) (precision to 100 m when measuring 10,000 km) Standards Units and dial gauge Micrometer Measures Hirokazu MATSUMOTO, Measurement Standards for Better Safety and Security Deputy Director, Metrology Institute of Japan Allowing lab-test results to be used anywhere in the Units and Measures world The exchange of materials is an indispensable part of our In lab tests, blood and urine samples are used to measure everyday lives. Yet the greater the quantity and variety of ma- levels of cholesterol, gamma-GTP, terial exchanged, the more difficult it becomes to exchange urinary proteins and the like, to ensure items directly. Precise information about those items is need- that patients’ levels of these substances ed in order to exchange them. For this purpose, a wide range are normal. These values must be of units is employed. identical (within a reasonable range) To use these units, a sufficiently large community of users at any hospital in the world. If they are must accept the use of a common set of measures in their ev- not, great confusion and danger may eryday lives. If the gradations in these measures – the units – result. Incidentally, no measurement differ among the people conveying information about a given standards for cholesterol have yet been item or transaction and those receiving it, or if the people established. AIST is currently working involved lack confidence in them, it becomes impossible to to develop measurement standards conduct transactions with confidence, For this reason, mea- for cholesterol and other key blood sures represent a keystone supporting our modern society. components.

Measurement Standards and How They Support Society

Mutual Recognition When countries mutually recognize the equivalence of national measurement standards to each other, the reliability of measurement exchanged among users in different countries will be secured. Consequently, in turn, smoother international trade will be possible. The World of the International System of Units (SI) Japan Calibration of a gauge block length National Standards Laser light using laser equipment m for Length Iodine-stabilized He-Ne m-1 rad laser National measurement standards m2 luminous intensity mass m3 Iodine-stabilized He-Ne lasers = Primary measurement standards N.m lx sr kg T cd provide an extremely stable (established by AIST) kg/m 3 light source at a wavelength of lm m3/kg 633 nm. These lasers can real- Observation N W/sr ize an accurate “ruler” with a Uncertainty Pa J/kg scale division of half the wave- mol/ m3 －11 Sv Gy m/s2 length, using an interferome- 10 m/s ter. They are also used as a Pa.s H/m (precision to 0.1 mm when secondary measurement stand- measuring 10,000 km) A/m 2 J A/m ard. Secondary measurement 3 cd/m 2 kat J/m standards s W mol Practical Standards (calibrated by AIST) W/m2 H Gauge blocks account for ap- time C Wb amount Bq Hz of substance proximately 80% of the practi- Gauge Block V Traceability J/mo l cal length standards presently J（/ kg.K） in use. A gauge block is one of Calibration of a slide caliper The Dissemination F J（/ mol.K）℃ the end standards in a block using a gauge block J/K shape. The distance between System of Measure- F/m its two ends is used directly as ment Standards A Ω S K a length standard. Because of 10－7 that, there are over a hundred In the pyramid of traceability, electric current thermodynamic temperature of them that are different in (precision to 1 m when the number of standards in- size. Their shapes are main- measuring 10,000 km) creases starting with national Practical standards measurement standards at the All SI units are derived from of the seven basic units. tained by precision polishing (calibrated by accredited and their absolute length can top, moving down to secon- These units are mutually interconnected. For example, laboratories) dary standards, and further the unit of time (s) is necessary to define length. be realized with better than 0.05 m precision. down to working standards.

μ Reversely, working standards

－5 Measuring devices for general use * nm (nanometer; 1 nm = 1/100 10 (produced by manufacturers) millionth of a meter) (precision to 100 m when measuring 10,000 km) dial gauge Micrometer

Measurement Standards for Better Safety and Security Toshihide IHARA, Manager, Metrology Planning Office, Metrology Management Center

Measuring Critical Water-Supply Flowrate in Nuclear Monitoring Electromagnetic Environments Reactors Mobile telephones generate redio waves. To prevent Nuclear power plants work by splitting atoms to heat water. such emissions from interfering with pacemakers and other The resultant steam drives a turbine, which turns an electrical medical devices, mobile phone use is prohibited in hospitals generator. After passing through the turbine, the water vapor (which and on trains. Production of electronic is uncontaminated by radiation) is cooled and returned to the water devices, such as PCs, is governed supply, where it is once more sent to the nuclear reactor. Because by international standards regarding this flow volume is used to control the amount of heat generated by unnecessary generation of radio the nuclear reactor, obtaining an accurate assessment of the water waves. In Japan, such devices are thus flow is crucially important for the safety and generating efficiency requlated to ensure product safety. of the power plant. At AIST, we AIST prepares the measurement are hard at work developing highly standards needed to monitor and control precise technologies for measuring these high-frequency electromagnetic water-supply flow volumes in environments. nuclear reactors.

Measurement Standards and How They Support Society

cision. This check can only be performed by an accredited Traceability in Measurement Standards calibration laboratory. Using a technology called wavelength Measurement standards are the means by which standard interference, laser wavelengths can be used to accurately cali- gradations are stipulated to establish various units. In Japan, brate the gradations on a wide range of standard devices. The the National Measurement Institute of Japan (NMIJ), a center wavelengths of He-Ne lasers are then used on the secondary within the National Institute of Advanced Industrial Science standard device as well. By this process, capable private-sec- and Technology (AIST), determines the national standards tor calibration laboratories can calibrate a practical standard upon which measurement standards are based. NMIJ devel- device (a gauge block or other simple device that can be used ops and supplies standards that are trusted not only through- as a standard device by any end user). In the next phase, the out Japan, but in many countries overseas as well. gradations on this practical standard device are transferred to To make national standards available throughout society, the calipers, micrometers, and other devices used by the end a system of traceability must be established. Traceability is user. Here again, this work must be performed by an accred- provided by a verifiable system for assuring that the units of ited laboratory. measurement applied in a given environment are identical Japan’s private-sector calibration laboratories boast an with a higher national or international standard for that unit. exceptionally high level of technology. Today, some 35 ac- This article examines how traceability works, using units of credited laboratories use the designated secondary standard length as an example. The standard for length, the measure devices in their possession to perform calibration. Standing that stands at the apex of any traceability system, an elabo- at the top of the calibration pyramid, these certified operators rately constructed physical model representing one meter of play an extremely vital role in modern industry: the number length. For 70 years, this physical model of the meter served of practical standard devices each laboratory has calibrated as the national standard for length in Japan. The problem runs to the hundreds of thousands; and the number of types of with the use of physical models, of course, is that the loss of general instruments to which the calibrations on those prac- the physical model on which the system is based would re- tical standard devices are transferred number in the tens of sult in chaos. For this reason, efforts were made to develop a millions for each accredited laboratory. Because the traceabil- scientific method of defining the meter. Eventually, in 1960, ity system forms a pyramid, calibration is remarkably cost- wavelengths of light came to be used to determine gradation, effective in Japan, conveying national standards to the nation’ and “one meter” was defined as 1,650,763.73 times the wave- s users with enviably low levels of uncertainty. length of the light emitted by an atom of krypton. This innovation allowed length to be established using International Mutual Recognition contactless techniques. It reduced uncertainty regarding the As industrial technology and business operations become accuracy of the measurement value by two orders of mag- increasingly global in nature, the importance of interaction nitude, thereby greatly improving the technological basis with other countries is rising dramatically. These interactions upon which modern industry is founded. (“Uncertainty” is a depend on the ability to trust the measurement standards used measure of precision; it is the range in which the true value is by each country; one country’s units must be interchangeable sure to be found.) A further advance occurred in 1983, when with all others’. For this reason, the international community the speed of light was used to redefine “one meter” as the has been grappling with the need to establish mechanisms to distance that light propagates in a vacuum in 1/299,792,548 preserve the equivalence of various countries’ measurement of one second. The national standard for “one meter” is thus standards and provide society with measurement standards obtained from a stabilized wavelength produced by an iodine- that each country can recognize, so that the inspection and stabilized helium-neon (He-Ne) laser. test data of each country are interchangeable. This inter- However, the instruments we use on a daily basis were changeability is called the “international mutual recognition” not produced with direct comparison with this national stan- of measurement standards. Today 57 signatory countries and dard. Rather, the standard is transferred from a designated regions are members of the International Bureau of Weights standard device representing the national standard to a sec- and Measures (BIPM), the international standards body es- ondary standard device. The gradations on the secondary tablished by the Meter Convention. standard device are compared with those on the designated Countries signatory to the international mutual recogni- standard device, to “calibrate” the device, or verify its pre- tion process are required to prepare quality manuals, conduct

Optical Comb: A leading-edge technology for optical frequency measurement Hajime INABA, Wavelength Standards Section, Time and Frequency Division, Metrology Institute of Japan

The unit of length, the meter, is determined using red light km/s. from an iodine-stabilized He-Ne laser (ISHN laser) as a ruler (1). We now come to the question of how the optical frequency of A laser is a wave; its cycle length is called the wavelength. How the laser is measured. We must measure an optical frequency do we determine the laser wavelength? An optical wavelength is using the frequency standard, which is approximately 10 GHz calculated from the optical frequency (2). In the case of an ISHN microwave generated from a cesium atomic clock. However, laser, the optical frequency is approximately 474 THz (1THz =1 the optical frequency of an iodine-stabilized He-Ne laser is terahertz = 1012 Hz). Therefore, the wavelength is approximately approximately 474 THz, which is more than ten thousand times 633 nm because the speed of light is defined as 299,792.458 higher than the cesium frequency (3). Therefore, measuring an

(1) Iodine stabilized He-Ne laser (2) Relationship between optical (3) Frequency gap between the (4) Photonic crystal fiber wavelength and frequency frequency standard and the laser

fully transparent international comparisons, and submit to will soon allow measurements gathered in other countries peer reviews by specialists from other countries. Standards to be accepted “as is” in one’s own country, contributing that pass this rigorous process are registered in the BIPM da- significantly to smooth trade operations and economic tabase. Officially in operation from 2004 onward, this system growth.

Legally Designated Measurements That Protect the Security of Our Everyday Lives Takeshi ITO, Metrology Planning Office, Metrology Management Center

Measuring instruments for commercial guarantee their accuracy. transactions and certifications that have a Conventional mechanical instruments remarkably pervasive influence on private have adopted more and more advanced consumers are under strict legal control. electronics, such as CPUs. In this trend, For instance, they must pass mandatory new-generation measuring instruments have Taxi meter verification before they enter the market. been introduced. They can be applied to, They are called "specified measuring for example, centralized screening systems instruments". using LANs and the Internet, energy supply Today, there are 25 categories of legal management and its distribution system measuring instruments in Japan. Meters for with consolidated databases of measuring water, gas and electricity, for example, are results. In addition, they are able to interact requisite in daily life. Aside from these, in the with mobile devices such as mobile real world, weighing instruments to weigh phones and may allow the popularization foods in retail shops, alcohol hydrometers of electronic money with IC chips. Those to determine the alcoholicity in liquors, fuel innovations have brought drastic changes Gas meter dispensers at gas stations, and taximeters in the practices of transactions and logistic in taxis are helping people without always systems. Specified measuring instruments being noticed. Sphygmomanometers and are playing valuable roles in this society. clinical thermometers used for health They have become more and more im- management at home are similarly required portant as they incorporate increasingly Noise meter to pass verification. advanced technology. For environmental measurement, sound On the other hand, these remarkable level meters and vibration level meters are advances also pose a problem. To ensure examples of specified measuring instru the measurement accuracy, legal regulation ments. Concerning the contamination of has mainly dealt with hardware, which Water meter air, soil and water, measuring instruments has been sufficient so far. However, it has to determine minute quantities of pollutant been expanded to installed software today, such as dioxin, which have drawn public because the development of information attention, are also subject to verification. technology has increased the risk of illicit The period of validity of verification is interference and falsification. To meet the limited. Specified measuring instruments emerging needs of software protection, AIST must be subjected to regular inspections to is engaged in the research of this field. Commercial weighing scale

optical frequency using the cesium frequency as a standard was discrete like a comb (6). extremely difficult. The frequency intervals of a comb are uniform. If the intervals At AIST, the investigation of optical frequency measurement are locked to an atomic clock, these comb frequencies are also has proceeded. As a result, we have developed a special light ﾒ determined accurately (7). A locked optical comb appears as optical frequency comb, which is a bridge between the microwave though a million stabilized lasers form a line at uniform intervals (8). frequency region and the optical frequency region. An optical Various laser frequencies can be measured over 1000 times frequency comb can be generated using a femto-second mode- more accurately than conventional techniques by using an optical locked laser and a photonic crystal fiber (4). comb as an optical frequency ruler. These accurate lasers As shown in the photo (5), this optical frequency comb will improve semiconductor processing precision, for example. involves various color components, similarly to a rainbow. Furthermore, using this technique, contributions to the optical However, its micro-structure is not continuous like a rainbow but communications are expected.

(5) Optical comb (6) Magnified optical comb (7) Frequency counter (8) Frequency measurement of a (Conceptual figure) laser using an optical comb as a frequency ruler

Measurement Standards and How They Support Society

Measurement Standards at Production Sites: Automobiles Tomohiro MOCHIZUKI, Measurement Engineering Department, Nissan Motor Co., Ltd.

adjusted in order. actually provide their products even if Measurement Standards The measurement standards used in they are not part of our corporate group. Indispensable for Automobile production processes such as these are For that reason too, the importance of Inspections traceable to national standards. A col- traceability in measurement is rapidly To retain a satisfied customer base, lection of 93 in-house standard devices rising to manage the quality of the parts we, automobile manufacturers, must is used in common by all companies for and devices we use. For example, Nis- guarantee the quality of the vehicles we precision management. At the level of san and Renault require their suppliers sell, and reduce production costs by re- secondary standard devices, about 400 to conform to common quality require- ducing defects through quality control. such devices, which are calibrated using ments, including ISO/TS 16949 — a set For both of these tasks, measurement the at-house standard devices, are in use of quality system requirements that ap- standards and measurement management at all worksites. Because the items pro- plies to the automobile industry. occupy a position of vital importance. duced at each plant vary from auto bod- Under these exacting conditions, Quality control in the automobile ma ies to engines and many other compo- manufacturers need to maintain highly nufacturing process proceeds in a step-by- nents, some 50–60 secondary standards precise in-house measurement standards step manner. First, inspection occurs at are required to manage the instruments and conduct continuous training of the level of individual parts. Manufactur- used in inspection. calibration technicians, expecting them ers must strictly guarantee that parts pass to improve their skills to sophisticated national regulations concerning the ba- The Increasing Importance of levels. Toward this end, we are work- sic functions of parts (running, turning, Traceability ing proactively to secure certifications stopping, etc.). Important security parts As multifaceted and complex as in various measurement categories from such as brakes and chassis are subjected the inspection of completed vehicles is, the Japan Calibration Service System to particularly stringent checks. for all of the basic items inspected — (JCSS), which is considered to be the Finally, when the car is fully as- brakes, wheel alignment, speedometer, Japanese version of ISO/IEC 17025. For sembled and ready to be shipped to mar- exhaust and much more — traceability instance, Nissan is already fully certified ket, a final inspection of the vehicle’s must be assured. No variance can be tol- in two categories: length (end measures) performance and various other factors is erated, even though the same engines and electricity (DC voltage). conducted. The list of items tested in this may be produced at different plants or The advance of economic globaliza- inspection is daunting, yet all items must the same type of cars may be built in dif- tion is driving a steady increase in the be identical to the test items used by the ferent countries. import and export of automobiles. Each Land Transportation Bureau. Once the Moreover, unlike the conventional importing country has its own set of vehicle is passed on to the inspection practice in the industry, parts and device laws governing these products. In many line, each inspection item is tested and suppliers anywhere around the world can countries, the traceability requirements are stricter than those in Japan. Ultimately, we would like to establish a one-stop testing process — a system in which, meeting common requirements, countries would accept one another’s measurements based on mutual trust in the measurement standards of each country. Because no such system yet exists, the international trade of automobiles still involves complicated and time-consuming processes. We must write test reports that follow the legal requirements of each country. These requirements can be broadly divided between the North American and European type, with many countries outside these two regions choosing to adopt one or the other. Responding to Advances in Technology Today’s automobiles are becoming more technologically sophisticated with each passing year. The rate of this advance is accelerating. Not surprisingly, the measurement standards required to build these products are changing in number and variety at a blistering pace. Photo 1 Welding process on a production line For example, as more automobiles are A battery of robots carries out the work with high precision. (Photo courtesy of Nissan Motor Co. Ltd.)

Measurement Standards in Action

Photo 2 Installing an engine unit Photo 3 Final inspection of a product fresh off the production Human skills and measurement standards play a vital role in ensuring the safety line and trustworthiness of automobiles. (Photo courtesy of Nissan Motor Co. Ltd.) A wide variety of measuring instruments are used. (Photo courtesy of Nissan Motor Co. Ltd.) installed with fuel cells, standards for ing as quickly with the standards they ly mandated standards. For all automak- electrical power, hydrogen and chemical require is no easy matter. ers, this process presents a formidable reactions must be devised and adopted. At the same pace as the technology challenge in the coming years. These new needs may arise full-blown furnished to customers, we must rush to within the space of a year, but respond- calibrate our products according to new-

Measurement Standards FAA demanded NIST traceability in Aircraft Maintenance of other countries. Toshirou ITOU, Quality Assurance Department, Japan Airlines Advancement of For airline companies, nothing is more decisive for the International Recognition safety of passengers than aircraft maintenance. Following a tragic airplane crash in 1996, the United States Federal Aviation Administration (FAA) handed down a requirement that all instruments used in the maintenance of US-registered Traceability to other NMIs aircraft provide National Institute of Standards and Technology was also acknowledged. (NIST) traceability, whether the maintenance provider is based in the United States, Japan, or any other country. Aircraft maintenance requires a dizzying variety of instruments micrometers, calipers, torque wrenches, deploy instruments traceable to Japanese standards in the thermometers, thermocouples, voltage meters, ammeters maintenance of US-registered aircraft and their parts. At and others. Ensuring NIST traceability for each and every about the same time, in 1999, a global Mutual Recognition one of these instruments was grievously time-consuming Arrangement (MRA) was concluded with respect to the field and incurred enormous costs. Unable to square this circle of measurement standards. This framework lent impetus alone, Japan’s airlines turned to the then Agency of Industrial to the development of an organized system of international Science and Technology (AIST) for advice. This consultation comparison and mutual recognition for measurement produced an arrangement between AIST and NIST for standards on a global scale. cooperation in the field of measurement standards. In addition, As a result of these developments, in July 2003, the the two agencies used the results of comparisons of individual requirements contained in the FAA Advisory Circular, a notice measurement standards mutually to persuade the FAA that of FAA inspection operation, were changed, clearly permitting these measurement standards were equivalent. the application of NIST or other national measurement In this way, Japan’s airlines were able to win exemptions institutes’ traceability provisions. from the FAA’s traceability requirements, allowing them to

Measurement Standards and How They Support Society

Measuring Gene Quantities Mamoru KAWAHARASAKI, Bio-Medical Standards Section, Organic Analytical Chemistry Division, Metrology Institute of Japan

Deoxyribonucleic acid (DNA) con- of genes, which had originally been sists of a characteristic double-helix impossible to measure, to be quantified formed by four nucleotides, called bases, with reasonable accuracy. which pair specifically with one of the To measure the amplified gene, sev- other bases, in bonds called base pairs eral fluorescent dyes are used. Usually, (Figure 1). The genes, blueprints of the time needed to reach the threshold all organisms, are written by these four fluorescence intensity in the PCR gene bases. amplification is measured. If the original gene quantity before the amplification is Measuring Genes by Amplifying small, this interval will be longer; if the Genes original quantity is large, the threshold How can we measure gene quanti- will be reached more quickly. By creat- ties? At present, for gene quantification, ing a graph showing the relationship the fastest and most accurate method between the predetermined standard is a technique called “quantitative gene quantities and the times to reach PCR”. Quantitative PCR combines the threshold fluorescence intensity, Photo the polymerase chain reaction (PCR) and by measuring the time taken for an The left black device is a LightCycler(Roche Dia gnostics, GmbH, Germany) ; the right square one is a method with measurement of genes us- unknown quantity of a sample, it is pos- PRISM-7900 (Applied Biosystems, USA). ing fluorescent dyes. The PCR method, sible to measure the gene quantity in the which is a gene amplification method, original sample (Figure 2). The special amplifies a specific gene with a certain equipment needed to carry out quantita- base sequence to twice its size by single tive PCR is commercially available (see reaction. Theoretically, by a continuous photo). At present, AIST is participating in the reaction (i.e. chain reaction), a single This measurement technology is development of international protocols gene can be amplified infinitely (in prac- used to quantify the amount of geneti- to support the reliability of genetic mea- tice, the reaction will be stopped by lack cally modified organisms (soybeans, surement using quantitative PCR, in co- of available reagent, the heat degrada- corn, etc.) in foodstuffs. Future uses may operation with Consultative Committee tion of enzyme activity, and so on). This include such medical applications as pre- of Amount of Substances (CCQM) under technique allows even small quantities dicting the time for the onset of AIDS. the Meter Convention. )

HN2 y O t i s n

N C e

C t

N CH n HN C I e

CH c

C CH n C C e

O c H2N N N N s e

H H r

o gene quantities in samples u guanine cytosine l F ( s t

G---C c HN2 u d

O o G---C r

C N P 3 C CH N C R HN C T---A C CH P C f unknown sample threshold fluorescence HC o C CH C---G N N intensity m

O N h

H t i

H r

thymine adenine a g o L PCR Cycle (Time) s e l p m a S e h t e l n i p s

Figure 1 The structure of DNA m e i a t s i

Genetic information is written by four bases: adenine, thymine, cytosine and t n n a

guanine. y w u t i o Q t n n e k a n n e u u q G f n e o a n e n m g i h t i r a

g PCR Cycle (Time) o L

Figure 2 Principle of quantitative PCR Using a genetic sample whose quantity is already known, the time to reach a threshold level of fluorescence is measured and plotted on a graph. This graph is then used to measure the quantity of the gene in the sample whose genetic quantity was previously unknown.

10 Supporting Advanced The Development and Spread of Technology Nanotechnology and Related Measurement Standards Toshiyuki FUJIMOTO, Surface and Thin Film Standards Section, Materials Characterization Division, Metrology Institute of Japan

Research and development in nano- nanometer (billionth of a meter) scale, The World's Finest Scales with Minimum technology is making impressive strides. yielding new and unprecedented applica- Measurements of Several Nanometers Surprisingly, the roots of this discipline tions that transcend conventional scien- are ancient, even prehistoric. It is known, tific disciplines. To maximize the benefit for example, that the civilizations of from these unique properties, these tiny Mesopotamia created colored glass such individual structures and the functions 10nm as eye beads, which they fashioned into discovered for them must be evaluated jewelry and the like. Much later, around in terms of universal values. The most 500 AD, stained-glass techniques that effective route to achieving this ability had been developed in the Byzantine is to introduce measurement standards Empire began to find currency through that offer a universality transcending the much of the ancient world. differences among disciplines. AIST’ Schematic representation of a nanoscale for depth s NMIJ is at the forefront of activities direction Nanotechnology Blooms in the to prove the equivalence of Japan’s Age of Advanced Measurement national measurement standards with in- Technology ternational standards. Among the many Recent advances in measurement benefits of this research is its effective- technology have opened an exciting ness in protecting intellectual property new chapter in nanotechnology. Ancient rights. “nanotechnologies” guided by rough NMIJ is working proactively to experience are taking on new life, thanks develop a battery of valuable measure- 50nm to measurement technology. Developers ment standards. For example, NMIJ is can now manipulate the colors in stained working on certified reference materials Schematic representation of a nanoscale for in-plane glass with high precision, based on a for scales that are useful as measures direction clearer understanding of the relationship for the evaluation of various nanoscale between color and the oxides and metal three-dimensional structures, which properties of nanoscale fields and inter- particles embedded in the stained glass. form the building-blocks of nanotech- faces. This Institute is also working on Today these particles are being manipu- nology. Evaluation methods and certi- methods of evaluating the density and lated at the nanoscale level to develop fied reference materials for the sizes of hardness of ultrathin films. AIST expects new functional materials, requiring mea- nanoparticles and nanopores are also that these new measurement standards surement technologies with unprecedent- under development. To serve the need will not only find application in certain ed resolution and quantitative sensitivity. for design and evaluation of optical re- specialized fields, but will also serve as Nanotechnology makes use of unique cording media, the demand for which is the foundation on which the fusion and functions discovered in individual struc- growing exponentially, NMIJ is devis- integration of nanotechnology with other tures and configurations thereof on a ing methods of evaluating the thermal fields is maximized.

in the construction of radiation A Young Researcher Offers Her Views temperature standards in the middle Yukiko SHIMIZU, temperature range. It is challenging The editor interviews a young scientist, Dr. Yukiko Shimizu, to develop a more accurate standard Radiation Thermometry Section, Temperature and Humidity in an original way. It may have Division, Metrology Institute of Japan enormous impacts in the fields of science and technology. Research on temperature standards ─What is your research activity? in the nanoscale domain necessarily goes hand-in-hand with I’m constructing a dissemination system of the radiation the development of leading-edge measurement technologies. temperature standard in the middle temperature range from ─What are your future prospects? 100°C to 500°C. Radiation thermometers are widely used Although the principle of thermal-radiation thermometry in the fields of industry and science. Non contact and fast is based on the Planck radiation formula and the quantum determination of the temperature of even nano scale material devices such as semiconductor detectors, but the actual can be achieved using radiation thermometers. We have measurement processes are being developed on the classical already constructed a fast detection system with an infrared physics technologies such as design and fabrication of black- radiation thermometer and a laser source modulated at very body furnaces and set up of geometrical optics. By introducing high frequency. We succeeded in measuring the temperature techniques of micro-optics and quantum optics, we hope to and thermal conductivity of a 10µm thick metal thin film with develop a new thermal radiation measurement standard which a time constant of 300 nanoseconds. This technology should is more accurate, faster, and easier to use. Specific techniques lead to the development of the next-generation measurement we are working on include high-resolution measurement of standards such as nano-scale temperature standards. wavelength dependence of Planck radiation by using those of ─What interests you in this line of research? quantum optics and molecular spectroscopy. Many national institutes of standards are now competing

11 Measurement Standards and How They Support Society

Using the Avogadro Constant as a New Standard for Mass Kenichi FUJII, Fluid Properties Section, Material Properties and Metrological Statistics Division, Metrology Institute of Japan

Most people who have studied chem- surements has steadily increased. The artifact. Every 30 years or so, these cop- istry will probably remember an eccen- most startling progress of all has come ies are shipped to Paris for recalibration. tric portrait of Italian physicist Amedeo the past decade, thanks to the emergence Meanwhile, the mass of the artifact itself Avogadro (1776—1856) that crops up in of the X-ray crystal density method and fluctuates over time, rising as ambient many textbooks. Avogadro hypothesized growth technologies for silicon crystals. gases are adsorbed on its surface and that equal volumes of gases at the same Because the Avogadro constant is shrinking whenever it is cleaned. Natu- temperature and pressure contain equal such a fundamental constant in physics rally, these fluctuations compromise the numbers of molecules. This principle, and chemistry, the discovery of more stability upon which the present defini- now known as Avogadro’s law, is today accurate values for this number is of tion depends. The international commu- one of the most fundamental laws for monumental importance for basic chem- nity has therefore reached an agreement physics and chemistry. istry. The implications are likely to be in principle to redefine the kilogram felt not just in laboratories, but in broad according to a defined number of atoms, Improving the Accuracy of the areas of everyday life as well, because of using as accurate a value for the Avoga- Avogadro Constant one radical outcome: the redefinition of dro constant as possible. How many molecules are contained the basic unit of mass, the kilogram. in 1 mole of gas? Avogradro does not of- Toward an Atomic Mass fer a specific number for this quantity. At Redefining the Kilogram Standard the time, no proof of the existence of at- Of all the weights and measures The National Metrology Institute oms and molecules existed, and the the- that form the basis of the International of Japan (NMIJ) is striving to find ory on which these entities are based had System of Units, only the kilogram, the the most accurate value for the Avo- not yet been validated experimentally. unit of mass, continues to be based on a gradro constant, using a silicon single- Today the internationally accepted value material artifact. As discussed above, all crystal sphere precisely ground to 1 kg. for the Avogadro constant is 6.022 1415 of the other base units have already been First, the diameter of the high-purity ×1023 mol-1 (recommended in 2002 by redefined using physical principles. For silicon sphere is measured using laser the Committee on Data for Science and example, the unit of time, the second, is interferometry to obtain a highly precise Technology (CODATA)). The constant is based on the radiation period of the ce- measure of volume. The density of the defined as the number of atoms or mol- sium atom; the meter, the basis of length, sphere is then measured in vacuum, and ecules in a single mole, which in turn is defined in terms of the distance light its lattice constant (the gap between the is defined as 0.012 kg of 12C. Since the travels in a vacuum within a defined pe- atoms) and molar mass (average atomic beginning of the 20th century, numerous riod of time. weight based on the three stable isotopes researchers have engaged in an intermi- In its premises in the suburbs of of silicon existing in nature) are deter- nable series of tests and measurements, Paris, the International Bureau of Weights mined. striving to find an accurate value for the and Measures (BIPM) houses the arti- Drawing on these data, in 2002 Avogadro constant. Since the 1920s, fact that serves as the standard for the NMIJ succeeded in determining the Avo- when X-ray diffraction was deployed for kilogram. Each country signatory to the gadro constant with an uncertainty of the first time, the accuracy of these mea- Metre Convention holds a copy of this 10-7 level. This breakthrough contributed significantly to finding the most reliable value for the Avogadro constant as listed above. Based on our value as one of the fundamental input data, CODATA has conducted a comprehensive revision of no fewer than 200 fundamental physical constants. Future efforts are intended to further reduce isotopic impurities and improve the measurement accuracy to a few parts in 108, thereby realizing a new standard for mass based on the Avogadro constant. Through joint research on the international level, the current definition of the kilogram should be obsolete within 10 to 20 years, ushering in a much more readily verifiable and universally reproducible standard for mass.

Photo Using laser interferometry to measure the diameter of the silicon sphere

12 Measurement Standards Next-Generation Standards in the Future for High Temperatures Yoshiro YAMADA, Radiation Thermometry Section, Temperature and Humidity Division, Metrology Institute of Japan

the composition known as a eutectic, the A Novel Idea for a graphite-metal reaction can be prevented High-Temperature Fixed Point from proceeding further. As a result, Establishing standards for tempera- highly reproducible melting and freezing ture, a physical quantity that is not easy points are obtained. NMIJ has succeeded to grasp, depends widely on repeat- in establishing nine distinct fixed points, ability of the temperature under which from 1153˚C to 2474˚C, using carbon phase transitions occur in a substance. eutectics of a wide variety of metals. We Formerly, temperature was defined on have also demonstrated that fixed points the centigrade scale, using a scale of can be obtained at temperatures above 100 gradations from the boiling point of 3000˚C, using eutectics of carbon and water to its freezing point. Today scien- metal carbides. tists use the Kelvin scale, in which the triple point of water is used to define the How Made-in-Japan unit kelvin of the thermodynamic tem- Technologies Are Becoming perature. Additionally, a wide range of World Standards other fixed points, including the freezing For these “made-in-Japan” stan- points of pure metals, are used to realize dards technologies to win acceptance as and to disseminate the temperature scale. true global standards, it is necessary to Photo High-temperature fixed-point furnace Creating a fixed point, however, demonstrate temperature reproducibility for radiation thermometer calibration (Ru-C poses many difficulties at temperatures and determine temperature values with eutectic point) above 1000˚C, where matter reacts high precision. These tasks cannot be violently with other matter; the highest achieved in Japan alone; it must be dem- fixed point that can currently be used is onstrated that the temperatures can be approximately 1085˚C — the freezing reproduced by anyone, anywhere in the The International Temperature Scale, point of high-purity copper. Attempts to world. Worldwide agreement depends on the international convention on tempera- use metals with higher melting points independent verification of temperature ture standards that is revised approxi- have failed because the graphite crucible values by the world’s leading research mately every 20 years, comes up for used to contain the molten reference institutes. Many of these national metrol- revision within a few years. When the metal reacts with it, rendering the results ogy institutes are now involved in their International Temperature Scale is next unusable. research activities in this field. NMIJ is redefined, significant changes can be -ex At NMIJ, we devised a new method actively transferring knowledge and expected in the upper temperature ranges, that substitutes a metal-carbon alloy in perience to many national metrology in- where greater precision is an urgent place of a pure metal, thereby elimi- stitutes, promoting information exchange necessity for industries such as materials nating the graphite-metal reaction. By and collaborative investigation, while and energy. including carbon in the metal alloy at working to maintain its global lead.

Figure High-temperature fixed points using metal (carbide)-carbon eutectics

13 Measurement Standards and How They Support Society

Current Status of International Mutual Recognition and Future Directions Mitsuru TANAKA, Director, Metrology Institute of Japan

provide a guarantee of reliability to and sold and technologies exchanged Measurement Standards in people everywhere who use and depend with ever-increasing frequency. When Everyday Life: Development and on measurement results. The people who this happens, if the mutual traceability of Maintenance receive these measurement results from the measures — the measurement stan- As our modern world grows more NMIJ use them to supply measurement dards — on which they are based cannot complex and advanced, the measurement standards at the next level, which in turn be guaranteed, evaluating the product standards on which it depends continue informs the next level of standards, until or technology correctly becomes im- to expand both in the types of standard the work of NMIJ pervades every facet possible. Because it is impracticable to measures established and the purposes of modern Japanese society. verify this traceability every time a prod- to which they are applied. The require- Of course, the chain is no stronger uct is sold or a technology is transferred, ments upon which various quarters of than its weakest link: reliability must be the international community has struck society insist for these standards are vouchsafed in every part of this process upon the idea of guaranteeing the inter- demanding and complex: Technological of supplying measurement standards. reliability of each measurement standard development depends on uncompromis- This is why traceability, the series of in advance, so that mutual traceability ing precision; manufacturers must find links that join these various measure- can be guaranteed whenever the occa- the standards easy to use for quality-con- ment standards together to ensure their sion demands. This system of measure- trol purposes; the array of available ref- reliability, is extremely important. ment standards is known as International erence materials must be wide-ranging NMIJ is the organization that creates the Mutual Recognition. and comprehensive, to be an effective framework that guarantees the traceabil- In Japan, the institution that is re- tool in environmental regulation, and so ity of measurement standards to Japan’s sponsible for International Mutual Rec- on. national standards. ognition is NMIJ. To fulfill its respon- Moreover, each country must under- sibilities, NMIJ continuously conducts write the reliability of these measure- The Deployment of International international comparisons of national ment standards. The role of NMIJ/AIST Mutual Recognition and Japan’s measurement standards and peer reviews is to create and support national stan- Response by measurement standard experts. Under dards and disseminate the measurement With the relentless advance of glo- the Meter Convention, for example, in standards introduced. Thereby, it can balization, imported products are bought 1999 the national metrology institutes of numerous countries signed a mutual recognition arrangement. Preparations d 350 e t Physical Standards are being made to put this agreement in a n i 300 Basic Strategic force from 2004 forward. As an enthu- m e

s 250 siastic participant in this arrangement, s i Chemical Standards D 200 NMIJ has published an impressive body s Basic Strategic d r of outstanding results in international a 150 d

n comparisons and enjoys a sterling repu- a t 100 S tation on the international stage. f o 50 r First Period Second Period NMIJ’s brief differs from region to e b 0 region. In the Asia-Pacific region, with m

u Up to 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Fiscal Year N 2000 whose countries and regions Japan has long enjoyed especially close ties of Figure 1: NMIJ’s plan of measurement standards business and technological development, NMIJ has taken a leadership role in improving the region’s measurement International mutual Exports standards technologies. In the markets recognition of North America and Europe, assuring GPS quantitative and qualitative accuracy in Transfer Physical values using frequency standard as the transfer standard measurement standards is an important (frequency, time, voltage, length ...) issue in supporting the competitiveness of Japanese products and technologies. Information The Next Five Years: Targets and National Metrology Institute Industry Challenges Physical transfer standard (domestic, overseas) & (temperature, flow, pressure, NMIJ follows a road map (Figure 1) Calibration laboratories three-dimensional mass, AC/DC, radioactivity ...) that calls for the creation and dissemination of some 500 national standards, over the 10-year period from the beginning Internet Equipment setting information, acquired data, uncertainty information of its first four-year plan (2001–2004). In scope and ambition, this road map is Calibration certificate the equal of that pursued by the United States. The basic component of this road Figure 2: New format for dissemination of standards (remote calibration: e-trace) map involves the preparation of some

14 Future Prospects of Measurement Standards

Realization of Realization of domestic regulations one-stop testing consistent with international ones

International comparison Regulators International mutual recognition Maintenance of technological neutrality Utilization AIST Advanced analyzers Advanced analyzers

Transferring factories overseas Cooperation Cooperation Regulations of environment, ng uri Regulations of food and safety as me environment, ng rti ts Industry, academia, consumers po en food and safety Im um ies str tor Measuring instrument in ac g f rin standards fer Measuring instrument ns s Tra ea ers standards ov Commercial measurement Capital investment support Figure 3: System for reliability and international consistency in Measurement measurement infrastructure support

Measuring instrument standards

Figure 4: Japan’s response to the emerging tri-polar leadership structure in the world

300 standards. NMIJ is steadily pressing measurement standards to users in re- to materials and technologies and in the forward in the execution of this plan. In mote locations (Figure 2). These efforts regulations that govern society. Industry, the second four-year plan, beginning fis- include ongoing research to speed up the government and academia must work cal 2005, NMIJ will augment this basic supply of time and voltage standards and closely to introduce a level of sophistica- corpus of standards, aiming to establish to develop new formats for the supply of tion beyond that of conventional physi- and extend measurement standards in radioactivity and temperature standards. cal and chemical standards (Figure 3). certain strategic fields, in view of Japan’ Another issue of vital importance The call to action is no less urgent s global position in the world of indus- at NMIJ is the development of greater on the international front, where the con- trial technology. reliability in national and international tours of the process are often shaped by Unlike the national metrology insti- standards. As described above, NMIJ conflicting national agendas. The United tutes of other advanced countries, AIST is participating in joint international States continues to insist strongly on its incorporates not only National Metrol- research on the Avogadro constant to own national measurement standards, ogy Institute of Japan (NMIJ), but a host develop a new generation of highly ac- while the European Union is busily uni- of other agencies as well, devoted to the curate standards for mass that do not de- fying measurement standards as it knits fields of biotechnology, the environment, pend on artificial physical models for the itself into a cohesive economic bloc. energy and IT. It also conducts vigorous kilogram. It is using alloys to establish Moreover, the Asian-Pacific region is programs of exchange in each category. standards for high temperatures. In all of emerging as factory to the world and an As such, NMIJ can be expected to cre- these critically important efforts, NMIJ immense market in its own right. Con- ate national standards that will lead the plays a world-leading role. sequently, these three different powers world in reference materials for biotech- form a tri-polar configuration strength- nology, clinical pathology, medicine, the Emerging Needs in Measurement ening internal ties within themselves environment and nanotechnology, and in Standards (Figure 4). Under these circumstances, technologies for evaluating the reliabil- As those fields in which measure- expectations are high both at home and ity of instrumentation software. ment standards are used continue to abroad for Japan to continue to play Today’s industries require flexibil- expand, it is of paramount importance a leadership role in the Asian-Pacific ity in the dissemination of measurement to ensure that measurements conducted region. To serve such expectations, sur- standards. Users must be able to choose in Japan can be reliably traced to inter- rounded by a unique jumble of advanced the level of reliability that is appropriate national measurement standards. This industrial powerhouses and developing for them, according to the time and cost process of traceability forms part of the nations, Japan should keep making sug- required to obtain the standards. Accord- technological bedrock underpinning gestions as to what direction the region ingly, NMIJ will be hard at work techni- the sustainability of economic activ- should take with regard to measure- cally optimizing the formats by which ity and R&D in Japan. To execute this ment standards. At the same time, Japan measurement standards are delivered. process smoothly, a nationwide system should show her presence on the world We are developing remote calibration must be designed for the creation and stage by maintaining a high global pro- technologies, using electronic communi- dissemination of national standards, to file for Japan’s measurement standards. cations and IT to deliver highly reliable ensure traceability in the standards used

15 Publication Office, Public Relations Department, AIST AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, JAPAN Tel:+81-29-862-6217 Fax:+81-29-862-6212 E-mail:[email protected] http://www.aist.go.jp/ National Metrology Institute of Japan, AIST AIST Tsukuba Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, JAPAN Tel:+81-29-861-4120 Fax:+81-29-861-4099 http://www.nmij.jp/

Japanese version of the articles in this pamphlet were originally published as the feature articles in the 2004-10 issue of AIST Today. Printing March 2005