Delft nano-detector very promising for remote cosmic realms (Forwarded)

Delft University of Technology
Delft, The Netherlands

17 January 2007

Delft nano-detector very promising for remote cosmic realms

A miniscule but super-sensitive sensor can help solve the mysteries of outer
space. Cosmic radiation, which contains the terahertz frequencies that the
sensors detect, offers astronomers important new information about the birth
of star systems and planets. Merlijn Hajenius developed these sensors for
Delft University of Technology's Kavli Institute of Nanoscience, in close
cooperation with the SRON Netherlands Institute for Space Research. He will
receive his Delft University of Technology PhD degree on 19 January based on
this research subject.

The detector, called a 'hot electron bolometer', is based on the well-known
phenomenon that electrical resistance increases when something is heated up.
The use of a superconductor renders the detector extremely sensitive and
allows it to be used for radiation that until now could not be so well
detected.

The detector works for terahertz frequencies, which astronomers and
atmospheric scientists are extremely interested in. The detector's core is
comprised of a small piece of superconducting niobiumnitride. Clean
superconducting contacts that are kept at a constant temperature of 268 C
(five degrees above absolute zero) are attached to both ends of the
superconducting niobiumnitride.

A miniscule gold antenna catches the terahertz-radiation and sends it via
the contacts to the small piece of niobiumnitride, which functions as an
extremely sensitive thermometer. "By reading this thermometer, we can very
accurately measure the terahertz radiation. In Delft, we have set a world
record with this detector in the frequency area above 1.5 terahertz,"
Hajenius says proudly.

The results have convinced astronomers to use these detectors for the new
observatory in Antarctica (HEAT), and a new space mission (ESPRIT) has also
been proposed.

The 'maiden flight' of Hajenius' detector is planned for next year, but it
will not take place in a satellite used for studying cosmic clouds, but
rather in a balloon that will study the earth's atmosphere. The TELIS
instrument, which SRON is currently working on, will be equipped with a
Delft University of Technology detector and will measure the molecules in
the atmosphere above Brazil that influence the formation of the hole in the
ozone layer.

Note to editors

More information is available from:

Merlijn Hajenius
T: +31 6 28782566

Frank Nuijens, wetenschapsvoorlichting TU Delft
T: +31 15 278 4259

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