A series of measurements on the propagation speed of a He pressure front in a cryogenically cooled 75.3 m long, 4.3 cm i.d. stainless steel tube at 1.9 K and 4.25 K and a theoretical model for the phenomenon of limited propagation speed of such a He pressure front are described. The measurements have shown that it took 20 h for a He leak of to be detected at the other end of the 75.3 m tube at 1.9 K and if the leak was increased to still at 1.9 K, the time for the He to be detected at the distant end was reduced to 8.7 h. With the tube at 4.25 K, it took 5.0 h for a He leak of to be detected at the other end. The He travels through the tube in the form of a pressure front with a steep leading pressure gradient. A model involving the adsorption isotherm for He on stainless steel which is able to predict the time of arrival of the He pressure front at the distant end within 17% is described.
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Research Article| November 01 1997
Experimental test of the propagation of a He pressure front in a long, cryogenically cooled tube
E. Wallén; Experimental test of the propagation of a He pressure front in a long, cryogenically cooled tube. J. Vac. Sci. Technol. A 1 November 1997; 15 (6): 2949–2958. https://doi.org/10.1116/1.580890
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