Apparatus to measure the velocity of sound down to liquid helium temperatures with the optical method

✍ Scribed by A. Van Itterbeek; G.J. Van Den Berg; W. Limburg

• Publisher: Elsevier Science
• Year: 1954
• Weight: 179 KB
• Volume: 20
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(54)80044-9

✦ Synopsis

A description is given of the apparatus used in order to measure the velocity of sound in liquid hydrogen and helium with the optical method, indicated by D e b y e and by B i q u a r d. The light beam enters the cryostat at the top and passes an evacuated glass tube, shut off at the bottom by a plane parallel plug, before traversing the ultrasonic waves. After a reflection against an underlying flat steel mirror the light beam returns along the same way in order to leave the cryostat again at the top. Some results obtained in liquid hydrogen and liquid helium are mentioned.