The intense discussions on noise disturbance, particularly in the vicinity of wind turbines, raise the public awareness to infrasound (sound with frequencies < 20 Hz). Of major importance, thereby, is the knowledge about infrasound perception under realistic conditions, e.g. with binaural hearing. The monaural and binaural loudness perception of infrasound was investigated in a study with...

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...

Our brains process information via slow and fast brain currents. Up to now, it has been necessary to introduce electrodes into the brain to examine the latter. Within a cooperation between PTB and the Charité, these fast brain signals have been made visible from the outside for the first time – and a surprising variability has been observed. The measurements of these extremely small magnetic...

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.