The European Physical Journal Applied Physics (EPJ AP)

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Eur. Phys. J. Appl. Phys. 38, 53-59 (2007)
DOI: 10.1051/epjap:2007040

High mechanical Q-factor measurements on calcium fluoride at cryogenic temperatures

R. Nawrodt, A. Zimmer, T. Koettig, S. Nietzsche, M. Thürk, W. Vodel and P. Seidel

Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Helmholtzweg 5, 07743 Jena, Germany

ronny.nawrodt@uni-jena.de

(Received: 1 September 2006 / Accepted: 12 January 2007 / Published online: 22 February 2007)

Abstract
Mechanical Q-factor measurements of single crystalline calcium fluoride CaF₂ bulk material are presented. Resonant modes between 27 and 100 kHz were investigated on a cylindrical test sample ( $\varnothing$ $75~{\rm mm} \times 75~{\rm mm}$ ). For selected modes low temperature measurements of the mechanical Q-factor were done within a temperature range from 5 to 300 K. For the Q-measurements a ring-down technique was used. The substrate was suspended as a pendulum by means of a tungsten wire loop. The highest Q-factor has been achieved around 60 K with $3 \times 10^8$ which is the highest Q-factor reported on CaF₂ up to now.

PACS
43.40.-r - Structural acoustics and vibration.
43.60.+d - Acoustic signal processing.
62.30.+d - Mechanical and elastic waves; vibrations.
04.80.Nn - Gravitational wave detectors and experiments.

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