For decades, particle accelerators have been getting bigger and bigger. In the meantime, ring accelerators with circumferences of many kilometres have reached a practical limit. Linear accelerators in the GHz range also require very long construction lengths. For some years now, however, an alternative is explored: "tabletop particle accelerators" based on the laser excitation of charge waves in...

Nanoteilchen sind Tausendsassas. Unter anderem sind sie in der Medizin interessant, um Medikamente oder Impfstoffe gezielt tief in den Körper zu transportieren. Für solche Zwecke muss die Konzentration der winzigen Teilchen möglichst genau bekannt sein. Jetzt wurde in einer Kooperation zwischen der Physikalisch-Technischen Bundesanstalt (PTB) und der Firma LUM GmbH in Berlin ein neuartiges, sehr...

A key component of calibration facilities for traceability tasks is a secondary calibration method, which provides a way to transfer the calibration results obtained in a well-equipped standard laboratory to practical devices in the field. At PTB a sound tube apparatus has been developed, which enables this transfer for measurement devices for airborne infrasound.

The construction of a novel setup for hydrophone calibration was finalized by conducting extensive comparisons with further test sites at PTB. After publishing the results of these comparisons and conducting an internal audit, hydrophone calibration services up to 100 MHz can now be offered. Additionally, the results of primary calibrations are available to customers for the first time.

“Your temperature is 102 degrees – that’s a fever!” “Excuse me?” You could experience a confusing conversation like this if you feel ill during your vacation in the U.S. and need to see a doctor. Temperatures are measured in Fahrenheit in the U.S.; 102 degrees Fahrenheit are equivalent to 38.9 degrees Celsius. This type of confusion (or even serious misunderstandings!) occurs very rarely – at...