Kissinger, ThomasCharrett, Thomas O. H.James, Stephen W.Adams, AlvinTwin, AndrewTatam, Ralph P.2016-07-202016-07-202016-06-28Thomas Kissinger, Thomas O. H. Charrett, Stephen W. James, Alvin Adams, Andrew Twin and Ralph P. Tatam. Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry. 12th International AI VE. LA. Conference on Vibration By Laser and Noncontact Techniques: Advances and Applications, 29th June - 1st July 2016, Ancona, Italy. AIP Conf. Proc. 1740, 100004 (2016)978-0-7354-1397-9http://dx.doi.org/10.1063/1.4952696 https://dspace.lib.cranfield.ac.uk/handle/1826/10146A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm · Hz−0 5. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.en(c)2016 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in 12th International AI VE. LA. Conference on Vibration By Laser and Noncontact Techniques: Advances and Applications, 29th June - 1st July 2016, Ancona, Italy. AIP Conf. Proc. 1740, 100004 (2016) and may be found at: http://dx.doi.org/10.1063/1.4952696.Article