Logo PTB
symbolic picture: "magazines"

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.

PTB News 3.2020 - Scientific News

No secrets

Hardware components of an open-source low-field MRI scanner: pulse generator, high-frequencyamplifier, emitter/receiver switch with receiver pre-amplifier, excitation coil, gradient amplifier, x-, yandz-gradient coils for spatial encoding and MR magnets with field-homogenization inserts. A headphantom serves to illustrate the dimensions. The structural design plans will be published and madeaccessible to everyone for free; they will also be released for non-exclusive (even commercial) use.

Within the scope of an international cooperation project, PTB is participating in the development of a low-cost MRI scanner whose technological details will all be published as open-source hardware (OSH). The first images recorded by means of such OSH-MRI scanners are now available.

[ more ]
Schematic representation of the fluorescence excitation of a nanostructureconsisting of atoms of different elements (A, B, C). When excitation iseffected with an X-ray beam (E<sub>0</sub>) characteristic fluorescence radiation (E<sub>1</sub>, E<sub>2</sub>) is emitted.

Methods for the element-specific reconstruction of periodically nanostructured surfaces have been optimized at PTB. Such surfaces are used to manufacture ultra-modern integrated circuits. Measurements have shown that it is possible to characterize the spatial distribution of different atoms in nanostructures by analyzing X-ray fluorescence radiation.

[ more ]
Berkovich tip on a silicon AFM cantilever (large image), together with the ideal dimensions of a Berkovich tip (top left) and a lateral view of the manufactured tip (top right). The angular aperture is (143 ± 0.5)<sup>°</sup>, which is in good agreement with the definition of tips stated in the ISO standard. The effective tip height is approx. 1 μm and is thus sufficient for mechanical measurements close to the surface, e.g. for determining the indentation-depth-dependent electromechanical behavior of nanoscale semiconducting materials.

The novel picoindenter ‘made at PTB’ uses the tip of an atomic force microscope (AFM) as an indenter to characterize nanomaterials dimensionally and mechanically. This indenter has now been considerably enhanced: in the Laboratory for Emerging Nanometrology (LENA), a focused ion beam was used to produce pyramidal Berkovich tips on AFM cantilevers which can also be used in the picoindenter....

[ more ]
Schematic representation of the molecule-based single-photon source for applications in quantum radiometry, for example to calibrate a single-photon detector (1, SPAD) via a reference detector (2, analog). The value of g(2)(0) = 0.08 means there is a very small probability that two photons may be emitted at the same time. DBT: dibenzoterrylene.(© Pietro Lombardi)

Single-photon sources are so-called nonclassical light sources. In contrast to lasers or incandescent lamps, these sources emit light only as single quanta (photons). Applications of such sources are found in many areas of quantum technologies such as quantum-based imaging, quantum computing, quantum key distribution and quantum-enhanced optical measurements. Moreover, they are ideal for certain...

[ more ]
Schematic diagram (strongly simplified) of a Josephson impedance bridge combined with a quantum Hall resistor (QHR). The current for the measurement is supplied by two current sources (left and right); voltage is measured in a quantum-based way via two pulse-operated Josephson voltage standards (U<sub>1</sub> and U<sub>2</sub>). After aligning the bridge by adjusting the voltage ratios and phase angles, the voltage measured by the detector is zero; thus, the ratio of the impedances of the device under test (Z<sub>DUT</sub>) to those of the quantum Hall impedance standard (Z<sub>QHR</sub>) is equal to the ratio between the two bridge voltages U<sub>1</sub> and U<sub>2</sub> which is very precisely known.

Within the scope of a European metrology research project, PTB is investigating the utilizability of novel quantum Hall resistance standards based on graphene for impedance metrology. The activities aim to develop quantum-based impedance bridges to simplify the calibration of electrical AC voltage quantities for practice-oriented, flexible and efficient use, e.g. in calibration laboratories or in...

[ more ]
Overview of the database's contents. Each entry corresponds to a row in the table from top to bottom in the chronological order. Black pixels show availablevalues; white pixels indicate missing values.

A database developed at PTB provides more than 20 000 ECG images, machine-readable diagnostic findings and comments of cardiologists. This database was prepared primarily for the development of machine learning and is structured into training and test sections for comparability. The database, named PTB-XL, is publicly available at PhysioNet.

[ more ]

PTB News 3.2020 - Technology transfer

The optical inspection channel (yellow) allows the detection of the fluid level which arises around the vertical piston (gray).

To calibrate very small flowrates (< 0.1 ml/min), PTB is currently setting up a piston system to determine the volumetric flowrate. In this system, a liquid can be applied above the seal of the vertically moving piston with a low vapor pressure. The uncertainties normally inherent to this measurement process due to thermal inputs are minimized. An optical channel also allows leakages in the system...

[ more ]

Emitter and receiver antennas of future communication systems in the millimeter wave band and terahertz frequency range have to be oriented exactly towards each other to be able to communicate with each other. A new concept elaborated by PTB plans to combine two very high frequency omnidirectional radio range beacons that are oriented orthogonally to each other and are similar to those used in...

[ more ]
The two point light sources (fiber optics) are located on the object in motion. The image sensor registers the interference pattern whose orientation indicates the roll angle.

PTB has developed a cost-efficient and very simple procedure to measure roll angles in high-precision translation stages in optical metrology and industrial production. This procedure is based on two single-mode fiber optics and a conventional image sensor and requires no further optics. The two ends of the fiber optics whose ends have a fixed position to each other are located on the object in...

[ more ]

PTB-News 3.2020 - Micellaneous

Awards

Fabian Wolf , a staff member of the QUEST Institute at PTB, was honored with the “Carl Zeiss Award for Young Researchers”. With this prize, the Ernst Abbe Fund, a member of the Stifterverband für die Deutsche Wissenschaft (Donors’ Association for the Promotion of Science and Humanities in Germany), is recognizing Wolf's work on motional Fock states for quantum-enhanced amplitude and phase...

[ more ]

Dr.-Ing. Prof. h.c. Frank Härtig ist neuer Vizepräsident der PTB. Er löst damit Hon.-Prof. Dr. Roman Schwartz ab, der das Amt sechs Jahre lang innehatte. 

[ more ]

A research association made up of Leibnitz Universität Hannover (LUH), TU Braunschweig, TU Clausthal, Jade Hochschule Wilhelmshaven and PTB has been receiving support from the Federal State of Lower Saxony since July 2020 initially for 15 months to set up an innovation laboratory for hydrogen technology. After a conceptual phase, the most successful innovation laboratories will be selected for a...

[ more ]

The German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) is extending the Collaborative Research Center of the Leibniz Universität Hannover and PTB, “Designed Quantum States of Matter (DQ-mat) – generation, manipulation and detection for metrological applications and tests of fundamental physics”, for another four years with approximately 9.2 million euros in funding. (Contact: Piet...

[ more ]
Bereits jetzt sind große europäische Forschungszentren über ein Glasfaser-Netzwerk verbunden, in das hochgenaue Atomuhren Laserlicht einspeisen. (Abb.: Stefan Schröder/Uni Bonn)

A consortium of European National Metrology Institutes, the University of Bonn and highly specialized companies which shall be called “Clock Optical Network Services – Design Study” (CLONETS-DS) is to develop a design study for a future network for the distribution of high-precision optical frequencies and time signals starting on 1 October. The European Union will fund the project with 3 million...

[ more ]

On behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ), PTB has been supporting the establishment of quality infrastructure in emerging and developing countries for about 60 years. In May 2020, BMZ and PTB ratified a new agreement which significantly expands PTB's task. The volume for establishing quality infrastructure in countries partnered with German...

[ more ]