PTB for the public

A novel measurement setup has been developed at PTB for the primary calibration of ultrasonic hydrophones. Hydrophones are sensors used to determine ultrasonic pressure wave in liquid media. They are mainly used in medical engineering in order to test ultrasonic equipment. The new facility covers a larger frequency range and simultaneously exhibits lower uncertainty.

Extensive uncertainty analyses and innovative methods for uncertainty determination allow state reconstruction systems to be used for commercial transactions in the gas grids of regional utility companies in order to determine the energy content of natural gas. PTB has provided the preconditions for the use of these systems.

In cooperation with the Leibniz Institute for Baltic Sea Research Warnemünde, pH values of average-salinity sea water (5 to 20 g/kg sea water) have been measured at PTB for the first time in such a way that they can be traced to PTB’s primary pH standard. This ensures comparability of pH values measured in the sea, which is indispensable for applications such as the reliable quantification of sea water acidification.

In collaboration with Fraunhofer IPM in Freiburg/Breisgau, interaction cross sections for the photoionization of noble gases in the VUV spectral range have been measured at PTB’s Metrology Light Source (MLS). The results have allowed the existing datasets to be extended, and have smaller uncertainties and reliable metrological traceability to the International System of Units (SI). They can be used for applications in solar and atmospheric research, for the characterization of X-ray lasers and for the analysis of combustion gases.

The passage of time depends on the position of the observer in a gravitational potential. For a large mass such as the Earth’s, this effect can be measured by means of high-precision atomic clocks and used to determine the difference in height between two clocks. For the first time, PTB’s portable strontium optical clock has allowed flexibility in the selection of the place where one of the clocks is operated.

Ein Faktenblatt der Deutschen Physikalischen Gesellschaft und der Physikalisch-Technischen Bundesanstalt (PTB) zur Neudefinition des SI-Einheitensystems

„Vorhang auf und hereinspaziert!“ heißt es am 8. September in der Physikalisch-Technischen Bundesanstalt in der Bundesallee 100. Dann können Gäste einen Blick hinter die Kulissen einer weltweit tätigen Forschungseinrichtung werfen und Orte besuchen, die sonst nicht ohne Weiteres zugänglich sind. In 21 Laboratorien geben Wissenschaftler von 14 bis 20 Uhr Einblicke in ihre Arbeit. Über das ganze PTB-Gelände verteilt laden Vorträge, Führungen, Shows und Mitmach-Experimente ein, sich mit Wissenschaft auseinanderzusetzen – von spielerisch über unterhaltsam bis anspruchsvoll. Und immer wieder werden Gäste von der bevorstehenden Neudefinition des Einheitensystems hören. Was hat es auf sich mit den Veränderungen, die Kilogramm & Co bevorstehen? Kino und Open-Air-Rock runden den Abend ab, bis um 22 Uhr die Türen schließen. Sonderbusse pendeln zwischen der PTB und dem Kanzlerfeld. Weitere Informationen und einen Guide zum Tag der offenen Tür gibt...

Seltene Auszeichnung: Die Leibniz Universität Hannover hat Prof. Dr. Joachim Ullrich, Präsident der Physikalisch-Technischen Bundesanstalt (PTB), die Ehrendoktorwürde verliehen. Professor Ullrich wurde während der Eröffnung des interdisziplinären Forschungszentrums HITec (Hannover Institute of Technology) mit der Ernennung zum Doktor der Naturwissenschaften ehrenhalber ausgezeichnet.

The nucleus of thorium-229 possesses a property that is unique among all known nuclides: It should be possible to excite it with ultraviolet light. To date, little has been known about the low-energy state of the Th-229 nucleus that is responsible for this property. Together with their colleagues from Munich and Mainz, researchers at the Physikalisch-Technische Bundesanstalt (PTB) have now performed the first-ever measurements – using optical methods – of some important properties of this nuclear state such as the shape of its charge distribution. In this way, a laser excitation of the atomic nucleus can be monitored, thus allowing an optical nuclear clock to be realized that “ticks” more precisely than present-day atomic clocks. The scientists have reported their results in the current issue of Nature.

Lead, cadmium, mercury, and arsenic do not belong in medicinal products. International requirements for the quality of medicines have therefore become more stringent and introduced new control requirements. Hence, it makes sense to use high-accuracy reference solutions with defined contents of these four elements to be able to make the measurements traceable to the International System of Units (SI). Such reference solutions have now been produced in a joint project of the European Directorate for the Quality of Medicines and HealthCare (EDQM), the Joint Research Center (JRC) Geel, the German Federal Institute for Materials Research and Testing (BAM) and the Physikalisch-Technische Bundesanstalt (PTB). Since January 2018, they are commercially available at the EDQM.