Physikalisch-Technische Bundesanstalt

The Physikalisch-Technische Bundesanstalt (PTB) 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 Energy.

Physikalisch-Technische Bundesanstalt
– PTB –
Agency overview
TypeHigher federal institute
JurisdictionFederal Ministry for Economic Affairs and Energy
Agency executive
  • Joachim Ullrich, President[2]


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 Bundesgesetzblatt (Federal Law Gazette), volume 2008, part I, No. 28, p. 1185 ff., 11 July 2008] 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 (two of them in Berlin), 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 (Deutscher Kalibrierdienst, DKD) 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 euros at its disposal; in 2012, approx. 15 million euros were, in addition, canvassed as third-party funds for research projects.[3]

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 (currently two cesium clocks and, since 1999 and 2009, respectively, two cesium fountain clocks.[4]) 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 with the Internet can obtain the time also via the three public NTP time servers of PTB.[5]

In Berlin-Adlershof, PTB operates the MLS (Metrology Light Source) electron storage ring for calibrations in the field from the infrared (THz) to the extreme ultraviolet (EUV).

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.[6] One of the tasks of PTB’s "Metrological Information Technology" Department – in accordance with the German Gambling Ordinance (§ 11 ff. SpielV) – 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.[7] This is, however, irrelevant as, in a judgment of 3 March 2009,[8] 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 (see also: Act on the Proof Testing of Arms and Ammunition).

Sites and structure

The main site of PTB is in Braunschweig (Lehndorf-Watenbüttel). 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 (MLS); the latter is located in the Willy Wien Laboratory.

PTB Main Entrance

Main entrance to PTB in Braunschweig with the sculpture created by Friedrich Wilhelm Voswinkel

Luftbild Braunschweig PTB

Aerial photo of the Braunschweig site

Luftbild Adlershof PTB

Aerial photo of the Berlin-Adlershof site

Luftbild Charlottenburg PTB

Aerial photo of the Berlin-Charlottenburg site


PTB's atomic clock CS2

Bundesarchiv Bild 102-06493, Reichsanstalt für Maß und Gewicht

In the Reichsanstalt für Maß und Gewicht ("Imperial Institute for Weights and Measures" – RMG), photo probably published in 1928

Bundesarchiv Bild 102-11152, Reichsanstalt für Maß und Gewicht

At the Reichsanstalt für Maß und Gewicht ("Imperial Institute for Weights and Measures" – RMG) in February 1931

Braunschweig PTB-Atomuhr CS 4 (2012)

PTB's cesium atomic clock "CS 4", put into operation in 1992. Since 2005, it has been on exhibit in the Braunschweigisches Landesmuseum

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 "Kuratorium" (PTB's Advisory Board), which is composed of representatives from science, the economy and politics.

PTB is composed of the following 9 Divisions.:[9]

  1. Division 1: Mechanics and Acoustics (site: Braunschweig) with the following departments: Mass, Solid Mechanics, Velocity, Gas Flow, Liquid Flow, Sound, Acoustics and Dynamics
  2. Division 2: Electricity (site: Braunschweig) 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. Division 3: Chemical Physics and Explosion Protection (site: Braunschweig) 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 (site: Braunschweig) 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 EngineerinꞋ (site: Braunschweig) with the following departments: Surface Metrology, Dimensional Nanometrology, Coordinate Metrology, Interferometry on Material Measures, Scientific Instrumentation Department
  6. Division 6: Ionizing Radiation (site: Braunschweig) 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 (site: Berlin-Charlottenburg and Adlershof) 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 (site: Berlin-Charlottenburg) 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 (Administrative Services) and Q (Scientific-technical Cross-sectional Tasks) 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.


Two essential factors which led to the founding of the Physikalisch-Technische Reichsanstalt (Imperial Physical Technical Institute – PTR) 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 (1870/71), 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 (and other) 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" (named after its author Karl Heinrich Schellbach) ranked, among others, Hermann von Helmholtz and the mathematician and physicist Wilhelm Foerster.[10] 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.[11] 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-wave radiation. 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.

New structure and new physics

In 1914, the PTR President Emil Warburg discontinued the subdivision into a physical and a technical division and re-structured the PTR into divisions for optics, electricity and heat, with sub-divisions of a purely scientific and technical nature. Under Warburg's successor Walther Nernst, the Reichsanstalt für Maß und Gewicht (Imperial Institute for Weights and Measures – RMG) was, in addition, integrated into the PTR. A newly established division took over from the RMG extensive tasks with regard to the verification system as well as the measurements of length, weight and volume associated with the verification system. The profile of tasks was thus similar to that of PTB today: Through its own research and development, and through services building on this, the PTR was to ensure the uniformity of metrology and its continuous further development. As regards contents, the PTB was dedicated at that time to the so-called New Physics. This included, among other things, research on the newly discovered X-rays, new atomic models, Einstein's Special Theory of Relativity, quantum physics (based on the already mentioned work on the black-body radiator), and the investigation of the properties of the electron. Scientists like Hans Geiger, who established the first radioactivity laboratory of PTR, were involved in this research work. Walther Meißner succeeded in liquefying helium, which led him to the discovery of the superconductivity of a series of metals. In this connection, he recognized some years later – together with his colleague Robert Ochsenfeld – that superconductors have the property of displacing from their interior a magnetic field which has been applied from the outside – the Meißner-Ochsenfeld Effect.[12]

Nazi Germany

With the appointment of Johannes Stark as president on 1 May 1933, the ideology of National Socialism found its way into the PTR. The convinced advocate of a German Physics terminated diverse research projects on issues of modern physics to which he referred to as "Jewish", among them, in particular, works on quantum physics and on the theory of relativity. Stark also tried to enforce the "Führer" principle at the PTR: in 1935, he dissolved the Kuratorium and took over its competences himself. Jewish employees and critics of the NSDAP (such as Max von Laue) were dismissed. After World War II, Von Laue participated in the re-founding of PTB. Albert Einstein, who had been thrown out of the Kuratorium already before its dissolution, broke ties to PTR/PTB.

Under Stark and – after 1939 – under his successor Abraham Esau, the PTR strongly dedicated itself to armament research. A newly founded laboratory for acoustics was not only to investigate general – but mainly also military – fields of application. This included, among other things, the acoustic finding of artillery, the military utilization of ultrasound and the development of decoding procedures. In addition, researchers of PTR developed acoustic mines and a steering system for torpedoes which orientated itself on the sound field of traveling ships.[13] Due to its classical metrological tasks, the PTR was also closely connected with the armament industry of the Third Reich. Since exact measures are a basic requirement for the manufacture of military equipment, the PTR gained a key role in armament production and defense.[14] The extent to which the PTR was also involved in the German nuclear weapons project is controversial. It is, however, known that – prior to his time as PTR president – Abraham Esau conducted – until 1939 – a group of researchers dealing with nuclear fission. Later, he took over the specialist area "nuclear fission" in the Reich Research Council which supervised, from spring 1942 on, the German uranium project. Shortly after that, Hermann Göring subordinated the working group under the former PTR physicist Kurt Diebner to Division V for atomic physics at the PTR. Esau received the title "Authorized Representative of the Reichsmarschall for Nuclear Physics", a post which he, however, ceded to Walther Gerlach already at the end of 1943.[15]

To escape the bombing raids of the allies, the PTR was, in 1943, relocated at the initiative of the president and Thuringian privy councillor Abraham Esau[16] to different places in Germany (for example to Weida and Ronneburg in Thuringia and to Bad Warmbrunn in Lower Silesia). During the attacks on Berlin, the buildings of the PTR were heavily damaged. In 1945, the Reichsanstalt was virtually destroyed and the few departments which still existed were scattered all over the country.

Re-founding of PTB in Braunschweig and other PTR successors

Approximately from 1947 on, successor institutes were developed in addition to the PTR in Berlin-Charlottenburg, i.e. one in East Berlin – for the Soviet Occupation Zone – and one in the Bizone – and later Trizone. With the well-meaning support of the British Military Government, parts of the old Reichsanstalt were established in Braunschweig. The idea for this re-founding had been developed by the former PTR advisor for theoretical physics, Max von Laue, already during his internment in Farm Hall. In 1947, he succeeded in convincing the British authorities to make the former Luftfahrtforschungsanstalt (Aeronautical Research Institute) in Völkenrode near Braunschweig available to the PTR successor. In 1948, Wilhelm Kösters, who had been the director of Division 1 in Berlin for many years, became its first president. Many former PTR employees from Berlin, Weida and Heidelberg followed him to Braunschweig. The new institute was named ꞋꞋPhysikalisch-Technische AnstaltꞋꞋ (PTA) and, since 1 April 1950, ꞋꞋPhysikalisch-Technische BundesanstaltꞋꞋ. In 1953, the West Berlin PTR was integrated into this institute as ꞋꞋBerlin InstituteꞋꞋ while respecting the four-power status of Berlin.

In the German Democratic Republic (GDR), the Deutsches Amt für Maß und Gewicht (DAMG) had established itself with its principle seat in Berlin. After several renamings, this institute was designated Amt für Standardisierung, Meßwesen und Warenprüfung (Office for Standardization, Metrology and Quality Control – ASMW) during the last GDR years; the name already indicates that this office of the GDR had more extensive tasks than PTB in the Federal Republic of Germany (FRG), namely additional tasks in the field of standardization and quality assurance and in the area of activity of the Bundesanstalt für Materialforschung und -prüfung (BAM).

Growth and reunification

The young PTB grew rapidly in the years after its founding – both in terms of staff and in terms of financial resources. Not only its scientific metrological profile was extended, but also its palette of services rendered to industry, in particular in the form of calibrations of measuring instruments. In the 1970s, this led to the founding of the Deutscher Kalibrierdienst (German Calibration Service), which delegated service tasks to accredited, privately run laboratories and allowed PTB to concentrate itself on more demanding measurement tasks.

From 1967 to 1995, PTB operated the Experimental and Research Reactor Braunschweig. This reactor served in particular as neutron source for fundamental research, not for the investigation of nuclear energy. PTB dealt with this controversial subject from 1977 to 1989, above all due to the fact that the task "long-term management and disposal of radioactive waste"[17] had been assigned to it. Later on, this field of work passed over to the ″Bundesamt für Strahlenschutz″ (Federal Office for Radiation Protection) after same had been newly established. Today, PTB’s Division 6 deals with ionizing radiation in general. This also includes a highly sensitive trace survey station for radionuclides which has been measuring radioactive substances in ground-level air for meanwhile more than 50 years.[18]

The "Wende" ("political change") in Germany in 1990 also led to a "reunification in metrology". PTB took over parts of the ASMW (Office for Standardization, Metrology and Quality Control of the former German Democratic Republic), among them 400 employees, and the site Berlin-Friedrichshagen as additional field office (this has meanwhile been given up again). Other parts of the ASMW were integrated into the BAM. Despite a phase of staff reductions – after the strong expansion following reunification – PTB ranks today among the largest national metrology institutes in the world. As such, it is in charge of the realization and dissemination of the physical units and promotes the worldwide uniformity of metrology.


Issues of the PTB magazine "maßstäbe" published so far:
Issue No. Title Date of issue
1 Dimensionen der Einheiten September 2001
2 Größen des Sports June 2002
3 Zum Licht February 2003
4 Im Labyrinth des Zufalls December 2003
5 Kleine Größen December 2004
6 Zeitgeschichten September 2005
7 Die Unveränderlichen September 2006
8 Innenansichten October 2007
9 Die Gradmesser November 2008
10 Menschen im Labor December 2009
11 Kräfte messen May 2011
12 Meilensteine June 2013

The PTB magazine "maßstäbe", which is published approximately once a year, can be subscribed to free of charge or it can be downloaded from the Internet pages of PTB.[19] It contains articles about the quantities of physics. These articles are intended to be generally understandable and informative for the broad public.

In addition, PTB publishes the scientific information bulletin PTB-news three times a year. On four pages, it contains news from the fields of work "Fundamentals of Metrology", "Applied Metrology for Industry", "Medicine and Environmental Protection", "Metrology for Society" and "International Affairs". The PTB-news are published in German and in English.

PTB-Mitteilungen is the metrological specialist journal and the official information bulletin of PTB. It is published four times a year and contains original scientific articles as well as overview articles on metrological subjects from PTB's fields of activity. Each volume focuses on a main topic. As an official information bulletin, the journal stands in a long tradition which goes back to the beginnings of the Physikalisch-Technische Reichsanstalt (Imperial Technical Physical Institute - PTR, founded in 1887). Until 2014, "PTB-Mitteilungen" was also the official bulletin in which the type approvals granted by PTB as well as the tests and conformity assessments carried out by PTB were published in a section of its own [named "Amtliche Bekanntmachungen" ("Official Notes")]. With the new Measures and Verification Act which has been in force since 1 January 2015 and with the new Measures and Verification Ordinance, there is no longer a legal basis for these notices. From 2015 onwards, "PTB-Mitteilungen" is, therefore, a purely metrological specialist journal and does not publish any "Official Notes" any more.[20]


Presidents of PTB and of the Physikalisch-Technische Reichsanstalt Berlin-Charlottenburg:[21]

  • From 1888 on: Hermann von Helmholtz, founding president
  • 1895–1905: Friedrich Kohlrausch
  • 1905–1922: Emil Warburg
  • 1922–1924: Walther Nernst
  • 1924–1933: Friedrich Paschen
  • 1933–1939: Johannes Stark
  • 1939–1945: Abraham Esau
  • 1945: for a short time, until the dissolution of the PTR Wilhelm Steinhaus
  • 1947: re-founding in Braunschweig, temporary director Martin Grützmacher
  • 1948–1950: Wilhelm Kösters
  • 1951–1961: Richard Vieweg
  • 1961–1969: Martin Kersten
  • 1970–1975: Ulrich Stille
  • 1975–1995: Dieter Kind
  • 1995–2011: Ernst O. Göbel
  • From 2012 on: Joachim Ullrich


Employees of PTR and PTB were, among others: Udo Adelsberger, Walther Bothe, Kurt Diebner, Gerhard Wilhelm Becker, Ernst Engelhard, Abraham Esau, Ernst Gehrcke, Hans Geiger, Werner Gitt, Eugen Goldstein, Ernst Carl Adolph Gumlich, Hermann von Helmholtz, Fritz Hennin], Friedrich Georg Houtermans, Max Jakob, Hellmut Keiter, Dieter Kind, Hans Otto Kneser, Friedrich Wilhelm Kohlrausch, Wilhelm Kösters, Bernhard Anton Ernst Kramer, Johannes Kramer, August Kundt, Max von Laue, Carl von Linde, Leopold Loewenherz, Otto Lummer, Walter Meidinger, Walther Meißner, Franz Mylius, Walther Hermann Nernst, Robert Ochsenfeld, Friedrich Paschen, Matthias Scheffler, Adolf Scheibe, Harald Schering, Reinhard Scherm, Johannes Stark, Ulrich Stille, Ida Tacke, Gotthold Richard Vieweg, Richard Wachsmuth, Emil Warburg, Wilhelm Wien.

Similar organisations


  1. ^ Employees
  2. ^ Joachim Ullrich, President
  3. ^ ptb annual report on
  4. ^ Questions about time
  5. ^ NTP time servers of PTB
  6. ^ Technical Cooperation
  7. ^ Federal Ordinance on Voting Archived 2015-09-23 at the Wayback Machine
  8. ^ Federal Constitutional Court Archived 2016-01-30 at the Wayback Machine
  9. ^ Die PTB gliedert sich organisatorisch in 10 Abteilungen (9 Fachabteilungen und eine Verwaltung)
  10. ^ see Artikel über die Physikalisch-Technische Reichsanstalt in Meyers großes Konversationslexikon (1905) bei
  11. ^ see Helmut Rechenberg: Helmholtz und die Gründerjahre, in: PTR/PTB: 125 Jahre metrologische Forschung. PTB-Mitteilungen, 2012, volume 2, p. 9 on
  12. ^ PTR und PTB: 125 Jahre genau – Geschichte einer Institution on
  13. ^ Ulrich Kern: Forschung und Präzisionsmessung. Die Physikalisch-Technische Reichsanstalt zwischen 1918 und 1948. Bremerhaven 2011, p. 267.
  14. ^ Dieter Hoffmann: Die Physikalisch-Technische Reichsanstalt im Dritten Reich, in: PTR/PTB: 125 Jahre metrologische Forschung. PTB-Mitteilungen, 2012, volume 2, p. 30f on
  15. ^ Ulrich Kern: Forschung und Präzisionsmessung. Die Physikalisch-Technische Reichsanstalt zwischen 1918 und 1948. Bremerhaven 2011, p. 265.
  16. ^ Max von Laue: seine Bedeutung für den Wiederaufbau der deutschen Wissenschaft
  17. ^ PTR und PTB: 125 Jahre genau – Geschichte einer Institution on (PDF)
  18. ^ Pressemitteilungen der PTB: 50 Jahre Spurensuche
  19. ^ maßstäbe der PTB
  20. ^ PTB Press & What's New
  21. ^ Geschichte der PTB und PTR in 125 Jahre metrologische Forschung, PTB Mitteilungen 2/2012, pdf


  • Hermann von Helmholtz: Zählen und Messen, erkenntnistheoretisch betrachtet. Original publication in: Philosophische Aufsätze, Eduard Zeller zu seinem fünfzigjährigen Doctorjubiläum gewidmet (dedicated to Eduard Zeller on the occasion of the 50th anniversary of his doctoral degree. Leipzig 1887. Fues’ Verlag. pp. 17–52. Digital edition: Heidelberg University Library, Heidelberg, 2010.
  • Johannes Stark (editor): Forschung und Prüfung. 50 Jahre Physikalisch-Technische Reichsanstalt. S. Hirzel, Leipzig 1937.
  • H. Moser (editor): Forschung und Prüfung. 75 Jahre Physikalisch-Technische Bundesanstalt/Reichsanstalt. Vieweg, Braunschweig 1962.
  • Jürgen Bortfeld, W. Hauser, Helmut Rechenberg (Ed.): 100 Jahre Physikalisch-Technische Reichsanstalt/Bundesanstalt 1887–1987. (= Forschen – Messen – Prüfen. Vol. 1) Braunschweig 1987, ISBN 3-876-64140-3.
  • David Cahan: Meister der Messung. Die Physikalisch-Technische Reichsanstalt im Deutschen Kaiserreich. Wirtschaftsverlag NW, Bremerhaven 2011, ISBN 978-3-86918-081-6.
  • Ulrich Kern: Forschung und Präzisionsmessung. Die Physikalisch-Technische Reichsanstalt zwischen 1918 und 1948. Wirtschaftsverlag NW, Bremerhaven 2011, ISBN 978-3-86918-082-3.
  • Dieter Kind: Herausforderung Metrologie. Die Physikalisch-Technische Bundesanstalt und die Entwicklung seit 1945. in: Forschen – Messen – Prüfen. Wirtschaftsverlag, Bremerhaven 2002, ISBN 3-89701-902-7.
  • Rudolf Huebener, Heinz Lübbig: A Focus of Discoveries. World Scientific, Singapur 2008, ISBN 978-9-812-79034-7.
  • Rudolf Huebener, Heinz Lübbig: Die Physikalisch-Technische Reichsanstalt. Ihre Bedeutung beim Aufbau der modernen Physik. Vieweg+Teubner, Wiesbaden 2011, ISBN 978-3-834-81390-9.
  • Brigitte Jacob, Wolfgang Schäche, Norbert Szymanski: Bauten für die Wissenschaft – 125 Jahre Physikalisch-Technische Reichsanstalt/Bundesanstalt in Berlin-Charlottenburg 1887–2012. JOVIS Verlag, Berlin 2012, ISBN 978-3-86859-163-7.
  • Imke Frischmuth, Jens Simon (Eds.): A Metrological Textbook. The Art of Measuring at PTB – in the Past, Present and Future. Wirtschaftsverlag NW, Bremerhaven 2012, ISBN 978-3-86918-301-5.

External links

Coordinates: 52°17′43″N 10°27′49″E / 52.29528°N 10.46361°E

Cryogenic current comparator

The cryogenic current comparator (CCC) is used in the electrical precision measurements to compare electric currents with highest accuracy. This device exceeds the accuracy of other current comparators around several orders of magnitude and is used in electrical metrology for highly precise comparative measurements of electric resistances or for the amplification and measurement of extremely small electric currents.

The CCC principle goes back on Harvey and is based substantially on the properties of superconductors. CCCs make use of macroscopic quantum effects that occur in superconducting materials or circuits underneath their critical temperature of typically a few kelvins. The term “Cryogenic Current Comparator” stems from κρυος (Gr. frost, ice) and comparare (Lat. compare). The two quantum effects used in a CCC are the ideal diamagnetism of the superconductor, caused by the Meissner effect, and the macroscopic quantum interference of currents in a superconducting quantum sensor.

For the comparison of two currents these are fed through two wires which are led through a superconducting tube. The Meissner effect induces a screening current on the inner surface of the tube, flowing opposite to and being exactly as large as the sum of the currents inside the tube. Thus, this shielding current exactly cancels the magnetic field inside the tube produced by the currents in the wires. The screening current flows back across the outer surface of the tube, giving rise to a magnetic field in the room outside of the tube. This field is detected by a highly sensitive magnetometer, acting as a null detector. The signal of this null detector thus is a measure for the equality of the currents; in particular it is zero if the two currents are of exactly equal magnitude. The important and crucial point characterizing the CCC is the fact that the magnitude of the screening current and its distribution on the surface of the superconducting screen are independent of the position and the path of the wires inside the tube.

Typical for a CCC is the use of a SQUID magnetometer as null detector for the magnetic field (SQUID = Superconducting Quantum Interference Device). These are capable of detecting extremely small changes of the magnetic field corresponding to fractions of the magnetic flux quantum = h/2e ≈ 2×10−15 V·s (h is Planck's constant and e the elementary charge). The function principle of a SQUID is based on macroscopic quantum interferences of electric currents, arising in superconducting circuits (loops) with tunnel junctions.

Resistance bridges based on CCCs are used for the comparison of electrical resistances, in particular if highest-precision measurements are required, as there is the traceability of the resistance unit to the quantum Hall effect (QHE). In this way, measurements connecting standard resistors ranging within 1 ohm up to 10 kΩ to a QHE resistor of 12.9 kΩ are performed at several national institutes of metrology as, for instance, the National Institute of Standards and Technology (NIST, USA) or the Physikalisch-Technische Bundesanstalt (PTB, D). Here, electrical resistance comparisons using CCCs are accomplished with relative measurement uncertainties of only about 10−9.


DCF77 is a German longwave time signal and standard-frequency radio station. It started service as a standard-frequency station on 1 January 1959. In June 1973 date and time information was added. Its primary and backup transmitter are located at 50°0′56″N 9°00′39″E in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. The transmitter generates a nominal power of 50 kW, of which about 30 to 35 kW can be radiated via a T-antenna.

DCF77 is controlled by the Physikalisch-Technische Bundesanstalt (PTB), Germany's national physics laboratory and transmits in continuous operation (24 hours). It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the PTB. With Media Broadcast GmbH, a temporal transmission availability of at least 99.7% per year or under 26.28 hours of annual downtime has been agreed upon. Most service interruptions are short-term disconnections of under two minutes. Longer lasting transmission service interruptions are generally caused by strong winds, freezing rain or snow induced T-antenna movement. This manifests itself in electrical detuning of the antenna resonance circuit and hence a measurable phase modulation of the received signal. When the maladjustment is too large, the transmitter is taken out of service temporarily. In the year 2002, almost 99.95% availability, or just over 4.38 hours of downtime, was realized. The timestamp sent is either in Coordinated Universal Time (UTC)+1 or UTC+2 depending on daylight saving time.The highly accurate 77.5 kHz (approximately 3868.3 m wavelength) carrier signal is generated from local atomic clocks that are linked with the German master clocks at the PTB in Braunschweig. The DCF77 time signal is used for the dissemination of the German national legal time to the public.Radio clocks and watches have been very popular in Europe since the late 1980s and, in mainland Europe, most of them use the DCF77 signal to set their time automatically. Further industrial time-keeping systems at railway stations, in the field of telecommunication and information technology, at radio and TV stations are radio-controlled by DCF77 as well as tariff change-over clocks of energy supply companies and clocks in traffic-light facilities.

Ewald Kienle

Ewald Kienle (born 21 December 1928, Nußdorf nearby Ludwigsburg (today a part of Eberdingen)) is a German inventor and entrepreneur. He developed and produced electronic church organs.

Gerda Laski

Gerda Laski (4 June 1893, Vienna – 24 November 1928, Berlin) was an Austrian/German physicist known for her research in infrared radiation. She went to a private girls secondary grammar school in Vienna and graduated in 1913.

She earned her doctorate in physics from the University of Vienna in 1917 on "Size Determination of Submicroscopic Particles Based on Optical and Mechanical Effects". From 1918 to 1919, she worked as an assistant at the University of Göttingen and, in 1920, as an assistant in the Physical Institute of the Technical University of Berlin, where she was introduced to the experimental technique that became her major interest.Her early research concerned the Bohr model. Laski was a student of Peter Debye, who was awarded the Nobel Prize in chemistry in 1936. Debye studied the dispersion of light by Bohr's hydrogen model and found that the theoretical curve corresponded satisfactorily to the curve observed. Laski later showed agreement between theory and experiment, however based on an erroneous interpretation of data.

Laski's main research focus later on was infrared research. This included the examination of selected chemical substances by means of infrared radiation—a field of application. Beginning in 1924, Laski was the director of the Infrared Department at the Institute for Fibre Chemistry of the Kaiser Wilhelm Society, a department which was closed due to lack of financing. She then became a voluntary assistant at the Physikalisch-Technische Bundesanstalt (Imperial Physical-Technical Institute) in 1927, in order to establish an infrared laboratory.

After serious illness, the Kaiser Wilhelm Institute for Physics provided Laski with a monthly stipend until her death in 1928.Her final work was on special methods for infrared measurement and thermoelectricity. Her research also included studying natural infrared frequencies of diatomic Bohr gas molecules and their specific heat at high temperatures.

Gottfried Landwehr

Gottfried Landwehr (22 August 1929 – 24 January 2013) was a German physicist.

Landwehr was born in Osnabrück and studied physics in Karlsruhe. After that he worked at the Physikalisch-Technische Bundesanstalt in Braunschweig. He was one of the founders of the Max Planck Institute for Solid State Research in Stuttgart (1955) and headed the branch office in France until 1983. From 1968 to 1999 he was professor for experimental physics in Würzburg. Klaus von Klitzing who is known for the discovery of the integer quantum Hall Effect in 1980 (Nobel Prize 1985) was one of his students.

On the initiative of Gottfried Landwehr the well known Centre for semiconductor physics was founded at the Julius-Maximilians-Universität Würzburg. He is also associated with the founding of the chair of applied physics and the department of experimental physics V (biophysics).

Gottfried von Droste

Gottfried Freiherr von Droste (1908–1992), a.k.a. Gottfried Freiherr von Droste zu Vischering-Padberg, was a German physical chemist. He worked at the Kaiser Wilhelm Institute for Chemistry (KWIC). He independently predicted that nuclear fission would release a large amount of energy. During World War II, he participated in the German nuclear energy project, also known as the Uranverein (Uranium Society or Uranium Club). In the latter years of the war, he worked at the Reich’s University of Strassburg. After the war, he worked at the Physikalisch-Technische Bundesanstalt (Federal Physical and Technical Institute and also held a position at the Technical University of Braunschweig.

He was a Freiherr of the Westphalian noble family Droste zu Vischering.

Harald Schering

Harald Schering (November 25, 1880 – April 10, 1959) was a German physicist born in Göttingen.

He studied physics at the University of Göttingen, and earned his doctorate in 1904. Beginning in 1905 he was a scientific assistant at the Physics and Technology Institute in Berlin Charlottenburg; today known as the Physikalisch-Technische Bundesanstalt (PTB). His work at PTB primarily dealt with high voltage/high current research and development, and in 1914 he developed a measurement methodology for examining current transformers. In 1919 he attained the title of professor at PTB.

Beginning in 1927, Schering was a professor of electrical engineering and high voltage technology at the Technical University of Hanover (today known as the Leibniz University of Hanover). Today, the Schering Institute at Leibniz University is named in his honor.

Schering is remembered for invention of the Schering Bridge, which is an AC bridge circuit used to measure capacitance and the dissipation factor of capacitors.

Hitlers Bombe

Hitlers Bombe (Hitler's Bomb) is a nonfiction book by the German historian Rainer Karlsch published in March 2005, which claims to have evidence concerning the development and testing of a possible "nuclear weapon" by Nazi Germany in 1945. The "weapon" in question is not alleged to be a standard nuclear weapon powered by nuclear fission, but something closer to either a radiological weapon (a so-called "dirty bomb") or a hybrid-nuclear fusion weapon. Its new evidence is concerned primarily with the parts of the German nuclear energy project under Kurt Diebner.

International Forecourt Standards Forum

The International Forecourt Standards Forum is a UK-based European organisation which designs standards for connecting devices on a service station forecourt, such as dispensers, Tank Level Gauges, Price Signs, Car Washes and Outdoor Payment Terminals. In recent years additional standards have been added for Electronic Funds Transfer.

Formed in 1992 by a group of oil, pump and computer companies (including AGIP, BP, Petrofina, Mobil and Texaco), the principle of IFSF is to create standards so that devices from different manufacturers can interoperate without having to redevelop interfaces:

... there was great concern within the retail oil industry regarding the different protocols or interfaces used by equipment manufacturers [...] Proprietary protocols effectively locked customers to individual suppliers – who could often not meet the changing computer system needs of the Oil Company.

A similar effort was undertaken earlier in Germany by oil companies and the Physikalisch-Technische Bundesanstalt, resulting in the European Petrol Station Interface (“EPSI”) standard, but this was not used much outside Germany.

Standards are only available to paid members of the IFSF organisation.


LYRA (Lyman Alpha Radiometer) is the solar UV radiometer on board Proba-2, a European Space Agency technology demonstration satellite that was launched on November 2, 2009.LYRA has been designed and manufactured by a Belgian-Swiss-German consortium (ROB-SIDC, PMOD/WRC, IMOMEC, CSL, MPS and BISA) with additional international collaborations (Japan, USA, Russia, and France). Jean-François Hochedez (ROB) is Principal Investigator, Yves Stockman (CSL) is Project Manager, and Werner Schmutz (PMOD) is Lead co-Investigator.

LYRA will monitor the Solar irradiance in four UV passbands. They have been chosen for their relevance to solar physics, aeronomy and Space Weather:

the 115-125 nm Lyman-α channel,

the 200-220 nm Herzberg continuum channel,

the Aluminium filter channel (17-50 nm) including He II at 30.4 nm, and

the Zirconium filter channel (1-20 nm).The Radiometric calibration of the instrument is traceable to Synchrotron source standards, Physikalisch-Technische Bundesanstalt (PTB) and National Institute of Standards and Technology (NIST). Its stability will be monitored by onboard calibration light sources (light-emitting diodes), which allow distinguishing between potential degradations of the detectors and filters. Additionally, a redundancy strategy contributes to the accuracy and the stability of the measurements. LYRA will benefit from wide bandgap detectors based on diamond: it will be the first space assessment of a pioneering UV detectors program. Diamond sensors make the instruments radiation-hard and solar-blind: their high bandgap energy makes them quasi-insensitive to visible light (see also references in Marchywka Effect). The SWAP extreme ultraviolet (EUV) imaging telescope will operate next to LYRA on Proba-2. Together, they will establish a high performance solar monitor for operational space weather nowcasting and research. LYRA demonstrates technologies important for future missions such as the ESA Solar Orbiter mission.

Löwenherz thread

The Löwenherz thread is a largely obsolete metric thread form designed in the late nineteenth century and frequently applied in precision instruments. It is named after Dr. Leopold Löwenherz, who was the director of the metrology institute Physikalisch-Technische Bundesanstalt in Berlin.

Mobile metering

Mobile metering (recording of data using a mobile meter) is a technology which enables mobile recording of metering data. While railway companies such as the German Deutsche Bahn have been using this technology for years in their trains, it is now also being used for recording the charging transactions of electric vehicles (EVs). Weil/Neumann (January 2016). "Vergleichende Betrachtung der Sicherheitskonzepte von Mobile Metering und Smart Meter Gateways". Physikalisch-technische Bundesanstalt (National Metrology Institute of Germany). 125: 53–58.In the latter case, a mobile electricity meter is integrated either into the vehicle itself or into the respective charging cable. This, together with the necessary communication technology (SIM card), makes it possible to transmit charging data (down to the kWh) to a matching backend. Lean, switchable system sockets suffice for charging – they serve as outlets for the power grid. These system sockets can be reduced to a technical minimum, as the vehicle or the cable, respectively, already carry the necessary billing and communication technology. PTB-Anforderungen 50.7 (PTB-A 50.7) Elektronische und softwaregesteuerte Messgeräte und Zusatzeinrichtungen für Elektrizität, Gas, Wasser und Wärme. PTB (National Metrology Institute of Germany). 2002. This makes these sockets especially affordable and avoids running costs compared to conventional charging infrastructure, such as costs for maintenance or meter point operation.

As a result, precise metering, secure data transmission and efficient billing fulfill all preconditions for a comprehensive and future-proof charging and billing solution for electric mobility.


PTR can refer to:

PTR rifle, a family of modern, American-manufactured, semi-automatic rifles based on the Heckler & Koch G3 battle rifle

PTR record or pointer record, a type of DNS record in computer network configuration

PetroChina (NYSE: PTR), a Chinese oil company

Physikalisch-Technische Reichsanstalt, historical name of Physikalisch-Technische Bundesanstalt, a German research institute

Pool Test Reactor, a Canadian nuclear reactor

Planar ternary ring, an algebra used to coordinatize projective planes

Popstars: The Rivals, a British talent show

Paid to read, a type of online incentive-based advertising

Particle Transfer Roller, a device for cleaning motion picture film

Proton-transfer-reaction mass spectrometry, a chemical analysis technique

Pitrilysin, an enzyme

Public Test Realm , an environment where in certain digital games you can test aspects that are still in development

Robert Ochsenfeld

Robert Ochsenfeld (18 May 1901 – 5 December 1993) was a German physicist. In 1933 he discovered together with Walther Meissner the Meisner-Ochsenfeld effect.

Born in Helberhausen, Germany, Ochsenfeld studied physics at the Philipps University of Marburg. The subject of his PhD was the study of ferromagnetism. In 1932-1933 he worked at the Physikalisch-Technische Reichsanstalt (PTR) in Berlin in the low temperature group headed by Meissner. Leaving the PTR, he taught at the National Political Institutes of Education in Potsdam until 1940, followed by research for new weapons in World War II.

After the war, he worked until retirement in the Physikalisch-Technische Bundesanstalt (PTB), the successor of the PTR with focus on magnetic materials.


Völkenrode is a quarter of Braunschweig, Lower Saxony, Germany. Völkenrode, formerly a municipality on its own and part of the district of Braunschweig, was incorporated into the city of Braunschweig in 1974. Today, it is part of the Stadtbezirk Lehndorf-Watenbüttel.

During the Second World War, it was home to the Luftfahrtforschungsanstalt (Aeronautical Research Institute, LFA), a secret facility for airframe, aeroengine, and aircraft weapons testing.Völkenrode, and the LFA, were visited postwar by the British Ministry of Aircraft Production survey team, headed by Sir Roy Fedden. Today, the Physikalisch-Technische Bundesanstalt and the former Federal Agricultural Research Centre are located on the former LFA site.

Walther Meissner

Fritz Walther Meissner (German: Meißner) (December 16, 1882 – November 16, 1974) was a German technical physicist.Meissner was born in Berlin to Waldemar Meissner and Johanna Greger. He studied mechanical engineering and physics at the Technical University of Berlin, his doctoral supervisor being Max Planck. He then entered the Physikalisch-Technische Bundesanstalt in Berlin. From 1922 to 1925, he established the world's third largest helium-liquifier, and discovered in 1933 the Meissner effect, damping of the magnetic field in superconductors. One year later, he was called as chair in technical physics at the Technical University of Munich.

After World War II, he became the president of the Bavarian Academy of Sciences and Humanities. In 1946, he was appointed director of the academy's first low temperature research commission. Laboratories were located in Herrsching am Ammersee until 1965, when they were moved to Garching. Meissner lived alone with his two dogs for the last several years of his life. Meissner died in Munich in 1974.

Werner Gitt

Werner Gitt (born 22 February 1937 in Stallupönen, East Prussia, Germany) is a German engineer and young earth creationist. Before retirement, he was Head of the Department of Information Technology at the German Federal Institute of Physics and Technology (Physikalisch-Technische Bundesanstalt).

Werner von Siemens Ring

The Werner von Siemens Ring (in German orthography, Werner-von-Siemens-Ring) is one of the highest awards for technical sciences in Germany.It has been awarded from 1916 to 1941 and since 1952 about every three years by the foundation Stiftung Werner-von-Siemens-Ring. The foundation was established on 13 December 1916 on the occasion of the 100th anniversary of the birth of Werner von Siemens. It is located in Berlin and is traditionally managed by the Deutscher Verband Technisch-Wissenschaftlicher Vereine (DVT) (English: German Federation of Technical and Scientific Associations). Before 1960, the name of the award had been simply Siemens Ring (German Siemens-Ring or Siemensring).The award is presented as a golden ring with emeralds and rubies depicting the leaves and fruit of laurel, placed in an individually crafted cassette carrying the portrait of Werner von Siemens and the dedication to the recipient.

According to the statutes, patron of the foundation council is the President of Germany, and the President of the Physikalisch-Technische Bundesanstalt is the foundation council's executive chairman. The council votes on the recipients. Members of the council are the bearers of the ring and representatives of the member scientific and technical societies.

Time signal authorities

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