Beta-ray Measurement by Light-pipe

Precision Speed Measurement by Light

Driving Assistance Systems combine a variety of sensors with vehicle display, control and handling capabilities to improve driver performance and safety. As part of a project to evaluate new driving assistance systems using environmental sensors, engineers at Renault needed to measure the exact car speed in real time with better than 0.1 km/h accuracy. Common existing solutions are based on eit...

Measurement of the radial distribution of Cherenkov light generated by TeV γ-ray air showers

Using air showers induced by TeV γ-rays from Mrk 501, the radial distribution of Cherenkov light is investigated. The shower geometry is reconstructed from the stereoscopic shower images obtained with the telescopes of the HEGRA IACT system. With the core position known to better than 10 m, the light yield as a function of the distance to the shower axis is derived by comparing event-by-event t...

A Beta-Ray Microscope.

Local light-ray rotation

We present a sheet structure that rotates the local ray direction through an arbitrary angle around the sheet normal. The sheet structure consists of two parallel Dove-prism sheets, each of which flips one component of the local direction of transmitted light rays. Together, the two sheets rotate transmitted light rays around the sheet normal. We show that the direction under which a point ligh...

Measurement of local dissipation scales in turbulent pipe flow.

Local dissipation scales are a manifestation of the intermittent small-scale nature of turbulence. We report the first experimental evaluation of the distribution of local dissipation scales in turbulent pipe flows for a range of Reynolds numbers: 2.4x10(4)<or=ReD<or=7.0x10(4). Our measurements at the nearly isotropic pipe center line and within the anisotropic logarithmic layer show excellent ...