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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.

PTB News 2.2020 - Scientific News

Sample with atomic step heights, recorded with a confocal laser scanning microscope. Each of theterraces is an atomically smooth lattice plane of the silicon (111) crystal with a constant step heightof h ≈ 0.314 nm.

 

In the course of the revision of the International System of Units (SI), which entered into force on 20 May 2019, the international Metre Convention, upon a proposal from the Consultative Committee for Length (CCL), endorsed the use of the lattice parameter of the silicon crystal (i.e. the spacing between the atomic layers) as a basis of the secondary realization of the meter in the nanometer...

 

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The OTT system uses terminals for feeding in the data and at the target location. For remote locations, a number of bidirectional, inline optical amplifiers are used to compensate for signal attenuation in the fiber.

 

Each mobile telecommunications network requires synchronization between its components. Deutsche Telekom Technik AG has decided to test a method developed by the AGH University of Science and Technology in Krakow, Poland, for the future monitoring of selected points in its network. It is based on optical time transmission (OTT), which has been tested in cooperation with PTB, among others, on glass...

 

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Demonstrating coherently elevated emission: after a full revolution around the storage ring (which takes 160 ns), the emission of the electron bunch microstructured by the laser radiation measured with a photodiode is clearly more intense.

 

In cooperation with the Helmholtz-Zentrum Berlin (HZB) and Tsinghua University Beijing, it has been successfully demonstrated at the Metrology Light Source (MLS), PTB's electron storage ring in Berlin, that the first step of so-called steady-state microbunching (SSMB) is feasible. This paves the way for future synchrotron radiation sources with higher intensities.

 

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Typical measurement setup at PTB for the measurement of planar scattering parameters: on-wafer microwave probes over test structures on a silicon wafer.

 

PTB has provided evidence that on-wafer calibration structures manufactured on commercially available substrates may be used as transfer standards for reference calibrations. This will enable traceable planar scattering measurements in industrial applications for the first time.

 

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The new device consists of a hemisphere on which 15 individual spectrometers are arranged in such a way that 15 different solid angles can be measured simultaneously. In this way, it is possible to determine the main direction of incidence of the X-ray photons on a person and, in particular, on an eye lens at the same time, so that the time it takes to characterize a workplace during running operation in a hospital is limited to the absolute minimum.

 

After the commencement of the Radiation Protection Act (StrlSchG) on 31 December 2018, the limit values for the dose to the eye lens have been considerably reduced. In order to prove and comply with these new limit values reliably, it is necessary to assess whether the existing radiation protection measures are sufficient and whether additional monitoring of the staff is required. A suitable...

 

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Test sample with magnetic structures used for the measurements performed within the scope of the interlaboratory comparison. The light green areas consist of a magnetic layer; in the darker areas, this layer was removed by means of lithography.

 

So far, no internationally standardized measurement procedures have been available to measure magnetic field distributions that vary spatially on the nanometer scale. The NanoMag EMPIR metrology research project, which was spearheaded by PTB and has recently been completed with success, bridges this gap and will allow internationally comparable measurements of magnetic field distributions with...

 

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PTB News 2.2020 - Technology transfer

Measuring setup with sensors on a fork-like structure, accommodated at the equator of the sphere.

Nearly perfect spheres are used in various branches of industry, such as optics or industrial metrology. Conventional procedures to measure form error are, however, much too slow and tedious for the industrial manufacturing of such spheres. A new measuring device developed by PTB is reliable and more economical than existing systems and provides fast results. This device consists of two collinear...

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Experimental model of a Planck-Balance.

The high-precision Planck-Balance, developed by PTB in cooperation with TU Ilmenau, measures over a continuous mass range and works according to the principle of electromagnetic force compensation. To put it more simply: a weight placed on the one side of the balance for weighing is compensated for on the other side by an electric force. This electric force is inextricably linked to Planck᾽s...

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Diagrammatic sketch of the double-pass AOM prototype

Acousto-optic modulator systems (AOMs) are used to modulate the frequency and the intensity of laser radiation. If a beam passes twice through an AOM, this allows the frequency shift to be doubled while at the same time suppressing the primary beam frequency adequately. Such a setup is called a double-pass arrangement. Our new PTB design is based on a specific convolution of the beam path for use...

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PTB-News 2.2020 - Micellaneous

Faster, further, better – this development will continue even after 5G is introduced. A DFG project called “Metrology for THz communications” (Meteracom) is researching what concepts could look like for even higher transmission rates. The focus is on the terahertz frequency range in which more than 100 gigabits could be transferred per second in the future. That is approximately ten to one hundred...

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Eine Ampel mit den Farben rot, orange, gelb und grün.

PTB has implemented numerous measures to fight the coronavirus (SARSCoV- 2); for example, nearly all events planned for the near future have been cancelled, as have official trips – including those between PTB’s sites. All staff members working on site at PTB Braunschweig and PTB Berlin must follow strict hygiene and conduct regulations. Lastly, most PTB staff members are now working from home....

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