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PTB News

Three times a year, PTB News provides topical information from the varied spectrum of activities of the Physikalisch-Technische Bundesanstalt (PTB) consisting of fundamental research, legal metrology and PTB's various activities in the service of the economy.


Multichannel pipette while filling a multiwell plate (large picture) and scheme showing how fragments of nucleic acid are digitized in a droplet digital polymerase chain reaction (ddPCR) (inset). Here, digitizing means that each viral RNA fragment that has been found is assigned the value 1.

Droplet digital PCR has been used in international comparison measurements to ensure the quality of SARSCoV- 2 tests for the first time. Hereby, this method proved particularly successful to quantify the RNA concentration.

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Deformation of a ball plate made of tool steel with a mass of approx. 30 kg and an edge length of 620 mm

Ball plates and hole plates are measurement standards typically used to ensure the traceability of coordinate measuring machines. To arrange the plates vertically, one single supporting stand is often used that is placed laterally to the standard. Numerical simulations based on the finite-element method that were performed at PTB have shown that such an arrangement no longer fulfills the ever...

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Stabilized square vortex lattice (L: lattice constant of periodically arranged pillars; ROI: region of interest in which the vortex statistics in the experiment was compared to theoretical predictions)

In a cooperation project between PTB and TU Berlin, the experimentally observed turbulence formation in the novel class of active fluids was successfully described, and motion in such fluids was controlled.

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Transition frequencies of PTB’s strontium lattice clock measured from 2010 to 2019. The black bars and gray arrays indicate the transition frequency and uncertainty for the Sr transition as a secondary realization of the unit second recommended by the CIPM at the time of the respective measurement.

Optical clocks such as the strontium lattice clock are used for the secondary realization of the SI unit second and are now being envisaged as potential candidates for the redefinition of the unit of time. To ensure a seamless transition, it is necessary to know the strontium transition frequency in the present system, which is determined by caesium atomic clocks. The two types of clocks were...

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Emission spectra of radionuclides can be measured with metallic magnetic calorimeters (MMCs). An MMC spectrometer was set up at PTB which allows fundamental radionuclide data to be determined with previously unachieved accuracy. These data are of paramount importance as input quantities for certain activity determination methods for the unit becquerel to be disseminated with smaller uncertainties...

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The infrasound playback system consists of two sound generators (earphone transducers in an air-tight metallic housing). Sound is guided to a joint insert earphone via a flexible tube.

The growing number of infrasound sources in our environment is increasingly attracting society’s attention. Together with the Otto von Guericke University Magdeburg, PTB has investigated how humans perceive infrasound with their ears and whether the detection threshold of an infrasonic signal depends on whether it is composed of one or of several tones. This allows conclusions to be drawn as to...

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Electron microscope image of the columnar nanostructures on the silicon surface of the photodiode(Source: T. Pasanen/Aalto Univ.)

Photodiodes for the ultraviolet (UV) spectral range are used in a large number of applications such as spectroscopy, imaging, flame detection, water treatment and biotechnologies. So far, loss processes have considerably limited their responsivity. A novel photodiode allowed the quantum efficiency to increase from roughly 80 % to more than 130 %.

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Joachim Ullrich

The President of PTB has received the highest honor of the German Physical Society (DPG) for experimental physics: the Stern-Gerlach Medal. Furthermore, Prof. Dr. Ullrich will become the President of the DPG starting in April 2022 after his retirement from PTB.

Michael Rinker

Michael Rinker, a staff member of Department 1.5, Liquid Flow, has received an “OIML Letter of...

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The project “Die rundesten Kugeln der Welt – der deutsche Mittelstand und die PTB Hand in Hand” (The roundest spheres in the world – German SMEs and PTB working hand in hand) was awarded the Seifriz Prize which is awarded to projects in all of Germany by the Technologietransfer Handwerk e.V. association in Baden-Württemberg. 

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The Federal State of Lower Saxony, together with universities and research institutes in Lower Saxony, aims to develop a quantum computer in Germany by 2025.

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Reliable data

In the GEMIMEG-II project, which is being funded with 12 million euros by the Federal Ministry for Economic Affairs and Energy (BMWi), 

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The synchronization of clocks from connected computers and digital devices is a fundamental precondition for many distributed applications. The “Network Time Protocol” (NTP) which PTB also uses to disseminate “its” UTC(PTB) time is used especially often.

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At the new Collaborative Research Center “TerraQ – Relativistic and Quantum-Based Geodesy” which is initially being funded by the German Research Foundation (DFG) with 9.6 million euros until 2024, about 60 scientists from the fields of geodesy and physics are developing fundamentally new measurement technology, sensors and analysis methods for measurements in space and on Earth.

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