Bardeen talk – Wednesday, April 14, 11 a.m. in WH1E

Ram Dhuley is a Ph.D. candidate from Florida State University and the National High Magnetic Field Laboratory. Ram has applied to the Bardeen Engineering Leadership Program and will be interviewing on site on Wednesday, April 13.

His visit will include a talk given on Wednesday morning. All are welcome to attend.

Date: Wednesday, April 13

Time: 11 a.m.-noon

Location: WH1E

Title: Study of sudden loss of vacuum in a tube cooled by liquid helium

Speaker: Ram C. Dhuley Cryogenics Lab, National High Magnetic Field Laboratory Mechanical Engineering Department, Florida State University

Abstract: Modern LINACs for high energy physics research use superconducting radio frequency (SRF) technology with liquid helium (LHe) cooling. The SRF beam-line or the ‘cavity string’ of such a LINAC is essentially a long high vacuum channel immersed in LHe with interconnects near the atmosphere. Accidental loss of the beam-line vacuum to the atmosphere, say due to a rupture, is perceived to be catastrophic as the rupture will expose the LHe enclosed vacuum space to the warm atmospheric air. The air rapidly flowing in from the local rupture will propagate down the vacuum space, and on condensation on the cold beam-line, will transfer large heat fluxes to the LHe. Our research on this subject has mainly focused on understanding how in the presence of condensation, the in-flowing air will propagate down the vacuum space. The scenario is studied by venting near-atmospheric nitrogen gas (a substitute for air) to a vacuum tube immersed in a LHe bath and then measuring the gas front propagation speed along the vacuum tube. This talk will describe the design of our propagation measurement techniques and will briefly summarize our efforts of empirical and analytical modeling of the front propagation.