Logo PTB
Gateway for scientists

Science

News

 

Eine Thorium-Kernuhr könnte noch einmal deutlich genauer sein als alle bisherigen Cäsium- und auch die optischen Atomuhren. Das verspricht Vorteile für die Anwendungen präziser Zeit- und Frequenzmessung, aber auch für physikalische Grundlagenforschung. Nachdem das internationale Forschungskonsortium mit mehreren Veröffentlichungen bereits gezeigt hat, dass eine solche Uhr grundsätzlich realisierbar ist, zeigt nun der europäische Forschungsrat sein Vertrauen in das Projekt, indem er es mit insgesamt 13,8 Millionen Euro fördert. An dem interdisziplinären und internationalen Projekt „Thorium Nuclear Clock“ sind neben der Physikalisch-Technischen Bundesanstalt (PTB) Wissenschaftler aus Wien, München, Delaware (USA), Heidelberg und Aachen beteiligt. Das Synergy Programm des European Research Council (ERC) ist die am höchsten dotierte Forschungsförderung des ERC und konzentriert sich insbesondere auf Themen mit hohem Innovationspotenzial, die...

 

[ more ]

A further new EURAMET network is intended to establish Europe-wide uniform structures related to quality assurance in laboratory medicine and to guarantee the metrological traceability of important quantities in this field. In this way, the requirements of a new EU regulation on in-vitro diagnostics will be implemented.

[ more ]
Angle measurement using an autocollimator

 

To measure small angular changes in objects, autocollimators are used. The detector used for this purpose, often a two-dimensional CCD sensor, is illuminated by a linear reticle pattern. Its position on the sensor is detected and has a limited resolution due to the pixel size. In the new procedure, this reticle is projected onto the sensor at an angle set specifically for this sensor, relative to the pixel grid. Its position is then calculated by means of line-by-line averaging. The interpolation errors in the sub-pixel critical range of the sphere and thus hardly generates any parasitic reflection at all. Luminous flux can now be measured with far less distortion, which makes the transmission measurement considerably more accurate. (Technology Offer 475) ■ range are minimized and allow a better resolution of the position of the reticle᾽s image without additional components.

(Technology Offer 428)

 

[ more ]
Left: Color-coded spatial distribution of the electron temperature <em>T</em><sub>e</sub> in the nanostructures. Center: SEM cross-sectional image of the nanostructure. Right: Electron density distribution <em>n</em><sub>e</sub>. The false color representations left and right show the results of simulations.

 

Within the scope of a research consortium, researchers from PTB have succeeded in advancing as far as to reach a new regime of relativistic light/matter interaction. In the context of a compact laboratory experiment, extremely hot and dense plasmas were generated. These plasmas open up new perspectives for experiments on laser-induced nuclear physics and laboratory astrophysics.

 

[ more ]
cture of the JAWS chip with 3000 integrated Josephson junctions and of the photodiode chip carrier (PDCC) connected to the optical waveguide.

 

At PTB, a pulse-driven Josephson standard for the generation of AC voltages has been realized where the voltage pulses are synthesized by means of optical components. This has advantages compared to the conventional operating procedure where the driving voltage pulses are conducted onto the superconducting chip via RF conductors.

 

[ more ]
PTB's caesium fountain clocks CSF2 (in the foreground) and CSF1. The atoms are cooled by lasers in the lower part of the vacuum setup and then launched upwards. In the upper part of the setup, they are irradiated with microwaves during their flight.

 

PTB's two caesium fountain clocks, CSF1 and CSF2, have been established as primary frequency standards and as the basis of PTB᾽s time scale for a long time. Exhaustive investigations have now allowed the uncertainties of these two clocks to be reduced by a factor of 5 (CSF1) and 2.4 (CSF2). With relative uncertainties of 2.7 ⋅ 10–16 reached for CSF1 and 1.7 ⋅ 10–16 for CSF2, these two clocks range among the best in the world besides a few other fountain clocks.

 

[ more ]
The OBCA mounted next to the transfer standard on the translation system at PTB's Reduced Background Calibration Facility 2. (Photo credit: Fraunhofer IOF, CYMER)

 

At PTB, the reference radiation source of the EnMAP satellite for the remote sensing of the Earth has been calibrated with high resolution. This ensures the long-term comparability and traceability of its global measurement data from the fields of geobiology, geochemistry and geophysics.

 

[ more ]
Bild zur Presseinfo vom 2.7.2019

 

Scientists at the QUEST Institute at Leibniz University, Hannover, and the PTB, have, together with colleagues at the institute of Theoretical Physics at the Leibniz University, Hannover, and with colleagues of the National Institute of Optics in Florence, Italy, introduced a method based on a non-classical state adapted to two measurement parameters at once. This will enable precision measurements of molecules which could reveal interactions between conventional and dark matter. They report on their results in the current issue of Nature Communications.

 

[ more ]
Trial of a dental drilling guide produced by additive manufacturing for the drilling of holes to fit dental implants into artificial jaw models with only few abutment teeth. The drilling angle α and the drilling depth were measured by means of computed tomography

 

Medicine is placing high expectations on implants and auxiliary materials that are manufactured specifically for each individual patient. This can be done by means of additive manufacturing (3D printing), which allows nearly any complex shape to be produced. Before starting to use such implants widely, the medical sector and certification bodies demand proof of the fact that their high quality is matched and will remain stable over time. Within the scope of a European project, MetAMMI, PTB has provided the basis for the quality control of medical implants and auxiliary materials produced by additive manufacturing.

 

[ more ]
Freude über ein gelungenes Richtfest und eine erfolgverheißende Forschungszukunft (v.l.n.r.): Prof. Dr. Joachim Ullrich (Präsident der PTB), Petra Wesseler (Präsidentin des Bundesamtes für Bauwesen und Raumordnung), Marco Wanderwitz (Parlamentarischer Staatssekretär beim Bundesminister des Innern, für Bau und Heimat), Canan Rohde-Can und Eckart Rohde (Rohdecan Architekten GmbH, Dresden)

 

Walther Meißner, der Pionier der Tieftemperaturforschung, ist der Namenspatron des neuen Gebäudes, das die Physikalisch-Technische Bundesanstalt (PTB) auf ihrem historischen Gelände in Berlin-Charlottenburg bekommt. Es wird seit dem Jahr 2017 vom Bundesamt für Bauwesen und Raumordnung (BBR) errichtet. Jetzt naht die Fertigstellung des hochspezialisierten Wissenschaftsbaues, in dem es unter anderem um die Forschung rund um sogenannte SQUIDs gehen wird – eine Spezialität der PTB, bei der sie seit Jahrzehnten in der Forschung eine internationale Spitzenstellung einnimmt. Auch das „neue Kelvin“ bekommt hier gewissermaßen eine Heimat.

 

[ more ]