Physikalisch-Technische Bundesanstalt


The Physikalisch-Technische Bundesanstalt is the national metrology institute of the Federal Republic of Germany, with scientific and technical service tasks. It is a higher federal authority and a public-law institution directly under federal government control, without legal capacity, under the auspices of the Federal Ministry for Economic Affairs and Climate Action.

Tasks

Together with NIST in the USA and the NPL in Great Britain, PTB ranks among the leading metrology institutes in the world. As the National Metrology Institute of Germany, PTB is Germany's highest and only authority in terms of correct and reliable measurements. The Units and Time Act assigns all tasks which are related with the realization and dissemination of the units to PTB. All legally relevant aspects regarding the units as well as PTB’s responsibilities have been combined in this Act. Previously, all questions regarding the units as well as the role of PTB had been distributed among three laws: the Units Act, the Time Act, and the Verification Act.
PTB consists of nine technical-scientific divisions, which are subdivided into approx. 60 departments. These again are subdivided into more than 200 working groups. PTB's tasks are as follows: the determination of fundamental and natural constants; the realization, maintenance and dissemination of the legal units of the SI; and safety technology. This spectrum of tasks is supplemented by services such as the German Calibration Service and by metrology for the area regulated by law, metrology for industry, and metrology for technology transfer. As the basis for its tasks, PTB conducts fundamental research and development in the field of metrology in close cooperation with universities, other research institutions, and industry. PTB employs approximately 1900 staff members. It has a total budget of approx. €183 million at its disposal; in 2012, approx. €15 million was, in addition, canvassed as third-party funds for research projects.
The Units and Time Act entrusts PTB also especially with the dissemination of legal time in Germany. To have a time basis for this, PTB operates several atomic clocks. By order of PTB, the synchronization of clocks via radio is performed via the time signal transmitter DCF77 operated by Media Broadcast. Computers which are connected to the Internet can obtain the time also via the three public NTP time servers operated by PTB.
In Berlin-Adlershof, PTB operates the MLS electron storage ring for calibrations in the field from the infrared to the extreme ultraviolet.
Department Q.5 "Technical Cooperation" realizes projects of the German and international development cooperation in the field of quality infrastructure. These activities promote competitiveness as well as environmental protection and consumer protection in developing countries and in countries in transition. One of the tasks of PTB’s "Metrological Information Technology" Department – in accordance with the German Gambling Ordinance – is to grant type approvals for gaming machines which offer the possibility to make winnings. Also, according to the Federal Ordinance on Voting Machines, PTB is in charge of the type approval of voting computers. This is, however, moot as, in a judgment of 3 March 2009, the Federal Constitutional Court has declared the use of such voting machines to be inadmissible.
Weapons which may be carried with the Minor Firearms Certificate, i.e. weapons for shooting blanks or irritants and weapons used as signaling devices, require a PTB test mark for their approval. Occasionally, these weapons are also jointly referred to as "PTB weapons" and bear the PTA or PTB proof mark F.

Sites and structure

The main site of PTB is in Braunschweig. Other sites are in Berlin-Charlottenburg and Berlin-Adlershof. Divisions 1 to 6 as well as Division Q are located in Braunschweig. In Berlin-Charlottenburg Divisions 7 and 8 are located, and in Berlin-Adlershof the two electron storage rings BESSY II and the Metrology Light Source ; the latter is located in the Willy Wien Laboratory.
PTB is headed by the Presidential Board in Braunschweig, which is composed of the President, the Vice-President and a further member. Another executive committee is the Directors' Conference, with the Presidential Board and the Heads of the Divisions as members. PTB is advised by the italic=no, which is composed of representatives from science, the economy and politics.
PTB is composed of the following nine divisions:
  1. Division 1: Mechanics and Acoustics with the following departments: Mass, Solid Mechanics, Velocity, Gas Flow, Liquid Flow, Sound, Acoustics and Dynamics
  2. Division 2: Electricity with the following departments: Direct Current and Low Frequency, High Frequency and Electromagnetic Fields, Electrical Energy Measuring Techniques, Quantum Electronics, Semiconductor Physics and Magnetism, Quantum Electrical Metrology
  3. : Chemical Physics and Explosion Protection with the following departments: Metrology in Chemistry, Analytics and Thermodynamic State Behavior of Gases, Thermophysical Quantities, Physical Chemistry, Explosion Protection in Energy Technology, Explosion Protection in Sensor Technology and Instrumentation, Fundamentals of Explosion Protection
  4. Division 4: Optics with the following departments: Photometry and Applied Radiometry, Imaging and Wave Optics, Quantum Optics and Unit of Length, Time and Frequency
  5. Division 5: Precision Engineering with the following departments: Surface Metrology, Dimensional Nanometrology, Coordinate Metrology, Interferometry on Material Measures, Scientific Instrumentation Department
  6. Division 6: Ionizing Radiation with the following departments: Radioactivity, Dosimetry for Radiation Therapy and Diagnostic Radiology, Radiation Protection Dosimetry, Ion and Neutron Radiation, Fundamentals of Dosimetry, Operational Radiation Protection
  7. Division 7: Temperature and Synchrotron Radiation with the following departments: Radiometry with Synchrotron Radiation, Cryophysics and Spectrometry, Detector Radiometry and Radiation Thermometry, Temperature, Heat and Vacuum
  8. Division 8: Medical Physics and Metrological Information Technology with the following departments: Medical Metrology, Biosignals, Biomedical Optics, Mathematical Modeling and Data Analysis, Metrological Information Technology
  9. The Presidential Staff Office and the Press and Information Office as well as the Divisions Z and Q report directly to the Presidential Board. Division Q comprises, among other things, the Academic Library, the Legal Metrology and Technology Transfer Departments, the Technical Services, and the Technical Cooperation Department.

    History

Two essential factors which led to the founding of the Physikalisch-Technische Reichsanstalt were the determination of internationally valid, uniform measures in the Meter Convention of 1875 and the dynamic industrial development in Germany in the 19th century. Already in the Franco-German War, the stagnation in scientific mechanics and in the science of instruments had become evident in Germany. Increasingly precise metrology was required for industrial production. A considerable impact on the initiative for the founding of a state institute for metrology in order to promote the national interests of the economy, of trade and of the military was made – in particular – by the upcoming electrical industry under the direction of the inventor and industrialist Werner von Siemens. In contrast to the units of length and weight, no recognized methods and standards existed at that time in the field of electrical metrology. The lack of reliable and verifiable measurement methods for the realization of electrical measurement units was a pressing scientific and economic problem.
In 1872, some Prussian natural scientists joined forces and demanded the establishment of a state institute in order to solve this problem. The reason for this was that such a task was scientifically too ambitious for industrial laboratories and, in addition, not profitable for them, and classical training institutes were not suited for the task either. Among the supporters of the "Schellbach Memorandum" ranked, among others, Hermann von Helmholtz and the mathematician and physicist Wilhelm Foerster. Prussia, however, initially rejected their demands.
Not until some years later were Werner von Siemens and Hermann von Helmholtz, the "founding fathers" of the PTR, able to make their vision – the establishment of a research institute which was to link scientific, technical and industrial interests in an optimal way – come true. Finally, on 28 March 1887, the Imperial Diet approved the first annual budget of the PTR – the founding of the first state-financed, university-external, major research institution in Germany which combined free fundamental research with services for industry. Werner von Siemens ceded private land in Berlin-Charlottenburg to the Reichsanstalt. Hermann von Helmholtz became its first president. At that time, 65 persons were employed at the PTR – among them more than a dozen physicists – who disposed of a budget of 263,000 Reichsmarks. In its first decades, the PTR succeeded in attracting important scientists and members of the Kuratorium as employees, among them Wilhelm Wien, Friedrich Kohlrausch, Walther Nernst, Emil Warburg, Walther Bothe, Albert Einstein and Max Planck.

Birth of quantum physics

The first outstanding scientific achievement at the PTR was also closely connected with Max Planck. To decide whether electricity or gas would be more economic for street lighting in Berlin, the PTR was to develop a more precise standard for luminous intensity. For this purpose, in 1895, Otto Lummer and Wilhelm Wien developed the first cavity radiator for the practical generation of thermal radiation. Their measurements of the spectrum of the black-body radiation were so precise that they contradicted Wien's radiation law at long wavelengths. This caused one of the cornerstones of classical physics of that time to totter. The measurements prompted a decisive impulse on the part of Max Planck to divide thermal radiation – in an "act of despair", as he later declared – into separate portions. This was the birth of quantum physics.