6,042 research outputs found
Thermal detector model for cryogenic composite detectors for the dark matter experiments CRESST and EURECA
The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers)
and the EURECA (European Underground Rare Event Calorimeter Array) experiments
are direct dark matter search experiments where cryogenic detectors are used to
detect spin-independent, coherent WIMP (Weakly Interacting Massive
Particle)-nucleon scattering events by means of the recoil energy. The
cryogenic detectors use a massive single crystal as absorber which is equipped
with a TES (transition edge sensor) for signal read-out. They are operated at
mK-temperatures. In order to enable a mass production of these detectors, as
needed for the EURECA experiment, a so-called composite detector design (CDD)
that allows decoupling of the TES fabrication from the optimization procedure
of the absorber single-crystal was developed and studied. To further
investigate, understand and optimize the performance of composite detectors a
detailed thermal detector model which takes into account the CDD has been
developed.Comment: To appear in Journal of Physics: Conference Series; Proceedings of
Neutrino 2008, Christchurch, New Zealan
Tomographic readout of an opto-mechanical interferometer
The quantum state of light changes its nature when being reflected off a
mechanical oscillator due to the latter's susceptibility to radiation pressure.
As a result, a coherent state can transform into a squeezed state and can get
entangled with the motion of the oscillator. The complete tomographic
reconstruction of the state of light requires the ability to readout arbitrary
quadratures. Here we demonstrate such a readout by applying a balanced homodyne
detector to an interferometric position measurement of a thermally excited
high-Q silicon nitride membrane in a Michelson-Sagnac interferometer. A readout
noise of \unit{1.9 \cdot 10^{-16}}{\metre/\sqrt{\hertz}} around the
membrane's fundamental oscillation mode at \unit{133}{\kilo\hertz} has been
achieved, going below the peak value of the standard quantum limit by a factor
of 8.2 (9 dB). The readout noise was entirely dominated by shot noise in a
rather broad frequency range around the mechanical resonance.Comment: 7 pages, 5 figure
The 8-14-μ Appearance of Venus Before the 1964 Conjunction
In an earlier paper (Murray, Wildey, and Westphal 1963) we have described the detailed
mapping of the 8-14-μ radiation from Venus using the 200-inch Hale telescope.
This paper extends that work over a period of about 7 months from December 15, 1963,
to June 6, 1964. Detailed maps for 6 days are presented that show the morphology of
the upper-atmosphere brightness temperature and illustrate a number of anomalous
features near the cusps. The problem of atmospheric extinction and the derived brightness
temperature is discussed
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