The PTB's 1996 Annual Report published

The Physikalisch-Technische Bundesanstalt (PTB) Braunschweig und Berlin has submitted its Annual Report for the year 1996, which comprises 333 pages.

The PTB's Annual Report gives a survey of the institute's extensive work and of the results achieved in the year under review.

The PTB will be pleased to inform you in detail about its work. Please, address your inquiries to:

Pressestelle der PTB
telephone: +49 531/592-3005 through 3007
fax: +49 531/592-3008
e-mail: Helmut.Klages(at)ptb.de

If desired, arrangements will be made for discussions with PTB scientists. The Annual Report can be obtained from:

Physikalisch-Technische Bundesanstalt
Presse- und Öffentlichkeitsarbeit
Postfach 3345
D-38023 Braunschweig
or by e-mail: Edeltraud.Rau(at)ptb.de

Some interesting dates and information from the 1996 Annual Report of PTB

Highlights of the year:

For the PTB, the year 1996 was marked by the implementation of measures aimed at increasing flexibility and efficiency. A concept for a stricter organizational structure has been developed and implemented, which is to form the basis of more flexible working procedures. The number of organizational units has been clearly reduced, and work processes will in future be organized to an increasing extent within the scope of comprehensive projects.

During the past year, the discussions about the international development of metrology were strongly intensified. Owing not least to the ever closer ties between the countries' economies, particular significance is to be attributed to the equivalence of national standards and regulations. Therefore, the PTB is now as before strongly involved in activities on the regional and international levels.

An evaluation of the situation in the patent sector made on behalf of the Federal Ministry of Economics has confirmed the successful transfer of technology from PTB to industry. This means that the PTB fulfils one of its most prominent tasks, i.e. to contribute to increasing the efficiency of German industry.
In the course of the measures taken with a view to concentrating its Berlin premises on one site, the PTB held the topping-out ceremony for the former German Industrial Safety Museum in Berlin-Charlottenburg. In addition to a lecture hall urgently required by the Berlin Institute, modern laboratories will be constructed for the areas of heat measuring techniques and biomagnetic medical measuring techniques.

The space probe SOHO (Solar and Heliospheric Observatory) launched in Cape Canaveral on December 2, 1995 reached its orbit in March. First results and future measurements were discussed on the occasion of an international seminar jointly organized by PTB and ESA.

Concrete preparatory work has been started to initiate the decommissioning procedure under atomic law for the close-down and dismantling of the Braunschweig Research and Measurement Reactor (FMRB). Together with two particle accelerators and a facility for the irradiation with radionuclide neutron sources, the FMRB formed the basis of the experimental work of the PTB's Neutron Physics Division until the end of 1995.

To celebrate the discovery of radioactivity 100 years ago, the PTB held a colloquium on the topic of radioactivity. The PTB's work is an important prerequisite for reliable and uniform measurements which must be carried out by many authorities of the Federal Government and the federal states, which are responsible for the monitoring of environmental radioactivity, and by producers and users of radioactive sources and medicaments.

The growing need for measurement results traceable to national standards has resulted in a constant increase in the number of calibration laboratories accredited within the Deutscher Kalibrierdienst (German Calibration Service, DKD). Among these are for the first time a mobile calibration laboratory and laboratories in Russia and Greece.

From the field of research

• In 1996, one succeeded in manufacturing single electron tunneling (SET) transistors in classical oblique sputtering technology with tunnel dimensions of 40 nm. Experiments are now being made with a scanning transmission electron microscope to achieve a further reduction, smallest structures with dimensions below 20 nm being aimed at.
• Superconducting thin film circuits in niobium technology with integration numbers of up to 200 damped active Josephson contacts have been developed in the field of rapid single flux quantum (RSFQ) pulse logic. They will be used for the realization of digital information with magnetic flux quanta by electric voltage pulses of duration times of a few picoseconds and for processing at subtera hertz clock rates.
• In 1982, it had been pointed out for the first time that the effect caused by the electric field of black-body radiation (which can induce transitions between atomic
• energy levels and shift the position of the energy level through the dynamic Stark effect) is also of significance in the realization of the unit of time, as it changes the splitting of the hyperfine structure of the ground state of the caesium atom, 133Cs. The frequency shift predicted at that time was now proved for the first time by the PTB.
• Until a few years ago it was impossible to estimate the accuracy of measurement of coordinate measuring machines for any measurement tasks. The PTB has now developed a procedure which allows any measurement task desired to be simulated by computer and the accuracy of the results analyzed and optimized.
• The PTB is the first institute worldwide which has succeeded in using magnetometers made of so-called high-temperature superconductors (high-TC-SQUIDS) for the measurement of weak voltage waves of the brain and nerves. Signals with an amplitude of only 15 fT were recorded (which are about three thousand millionths of the earth's magnetic field). Such weak signals could so far be detected only by conventional magnetometers cooled with liquid helium.
• Owing to public discussions about potential health risks due to electromagnetic fields, calibrations of alternating magnetic fields with frequencies f <= 1 kHz are required to an increasing extent. To simplify these calibrations, a novel fluxgate magnetometer has been developed at the PTB for the measurement of magnetic a.c. and d.c. fields with industrial frequencies. As the sensor dimensions are small, the prototype available is also suited to measure stray magnetic fields in the vicinity of electrical devices.
• As the number of standards is large, high costs are incurred for the recalibration of gauge blocks. The PTB has therefore developed a method which allows length differences of up to 10 mm to be measured. This method leads to a considerable reduction of the costs involved in the calibration of the standards, and it increases the flexibility required for the measurement of unusual nominal dimensions.
• For the first time, a calibration device has been set up at the PTB for the measurement of dynamic forces, which meets the accuracy requirements of practice.
• After two years of development, a novel device for measuring the velocity of vehicles in road traffic is now available as a universal reference instrument for use in approval tests.
• In the past, the PTB fulfilled its task to distribute the legal time above all through operation of the DCF 77 time signal transmitter. An additional time information service by telephone is now offered, through which users can interrogate a coded time information.
• After a development time of several years, a Fizeau interferometer with spherical mirrors has been put into operation, with which sphere diameters of up to 100 mm can be determined. Spherical reference surfaces and evaluation of the interferograms by the phase shifting method allow an angular range of 60° to be covered in a single measurement.
• In the PTB's clean-room center, a measuring facility was set up for the measurement of cylindrical and cubic standards of the highest accuracy, which allows the geometrical shape and dimension of such standards to be measured in a single arrangement. This new measuring device will be used to measure density and volume standards within the framework of the PTB project for the redetermination of Avogadro's constant and to calibrate reference standards of industry.
• In the field of cryosensor technology, new fields of use for SQUIDs could be opened up. SQUID magnetometers, for example, have proved their worth in a field test for the geophysical exploration of the environment. It has also been proved that integrated resistive DC SQUIDs in thin-film technology are suitable for use in noise thermometry.
• Operation of the intense-field NMR tomograph has been started for research purposes. At the suggestion of, and in cooperation with, physicians of several Berlin hospitals, the development of a measuring method for checking the progress of multiple sclerosis has been included in the work program.

From the field of international cooperation:

• From June 17 to 20, the 20th Conference on Precision Electromagnetic Measurements (CPEM'96) organized by the PTB was held in the Civic Hall of Braunschweig. More than 600 scientists from 46 countries participated in this most important international conference in the field of highly precise electromagnetic measurements.
• It was for the first time after the inaugural meeting of the European Cooperation in Legal Metrology in 1989 that a committee meeting was held in Germany, in Berlin. WELMEC has become one of the most important partners of the EU Commission for establishing the requirements to be met by measuring instruments.
• The international conference "Advanced Mathematical Tools in Metrology III" was held in Berlin from September 25 to 28. More than 85 participants from 20 countries, among these for the first time participants from East European countries, discussed aspects of mathematics and software technology applied in metrology.

General information:

• In the year under review, work was carried out on a total of five research projects financed by the Federal Ministry of Economics, and on 176 projects financed by third parties; non-cash contributions from the Deutsche Forschungsgemeinschaft (DFG, German Research Association) were made use of in 15 cases.
• In 1996, another 21 DKD calibration laboratories were accredited; four accreditations were withdrawn. Compared with the previous year, the total number of accredited laboratories has thus increased by 10%, to a total of 185. Another 27 applications for accreditation have already been filed with the DKD Executive Office.
• The PTB's research and development work is reflected in about 590 publications and more than 820 lectures. 93 expert meetings and colloquia were held at the PTB.
• In 1996, the PTB laboratories carried out 8 146 calibrations and 8 945 tests in about 350 fields, and they granted 99 004 approvals in 72 approval categories. Within the framework of comparison measurements prescribed by law, 2 112 dosemeters were irradiated, the majority of them with X-rays or photons.
• The PTB's budget in 1996 amounted to (in million DM):

*Figures of previous year

The PTB's Press and Information Office has published special Press Releases informing about particularly important events at PTB. A survey of all Press Releases is given on page 30 of the Annual report.