An on-line acoustic fluorocarbon coolant mixture analyzer for the ATLAS silicon tracker

Bates, R. et al. (2012) An on-line acoustic fluorocarbon coolant mixture analyzer for the ATLAS silicon tracker. IEEE Transactions on Nuclear Science, 59(5), pp. 2367-2374. (doi: 10.1109/TNS.2012.2209895)

Abstract

The ATLAS silicon tracker community foresees an upgrade from the present octafluoropropane (C3F8) evaporative cooling fluid to a composite fluid with a probable 10-20% admixture of hexafluoroethane (C2F6). Such a fluid will allow a lower evaporation temperature and will afford the tracker silicon substrates a better safety margin against leakage current-induced thermal runaway caused by cumulative radiation damage as the luminosity profile at the CERN Large Hadron Collider increases. Central to the use of this new fluid is a new custom-developed speed-of-sound instrument for continuous real-time measurement of the C3F8/C2F6 mixture ratio and flow. An acoustic vapour mixture analyzer/flow meter with new custom electronics allowing ultrasonic frequency transmission through gas mixtures has been developed for this application. Synchronous with the emission of an ultrasound `chirp' from an acoustic transmitter, a fast readout clock (40 MHz) is started. The clock is stopped on receipt of an above threshold sound pulse at the receiver. Sound is alternately transmitted parallel and anti-parallel with the vapour flow for volume flow measurement from transducers that can serve as acoustic transmitters or receivers. In the development version, continuous real-time measurement of C3F8/C2F6 flow and calculation of the mixture ratio is performed within a graphical user interface developed in PVSS-II, the Supervisory, Control and Data Acquisition standard chosen for LHC and its experiments at CERN. The described instrument has numerous potential applications - including refrigerant leak detection, the analysis of hydrocarbons, vapour mixtures for semi-conductor manufacture and anesthetic gas mixtures.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bates, Dr Richard
• Authors: Bates, R., Battistin, M., Berry, S., Bitadze, A., Bonneau, P., Bousson, N., Boyd, G., Botelho-Direito, J., DiGirolamo, B., Doubek, M., Egorov, K., Godlewski, J., Hallewell, G., Katunin, S., Mathieu, M., McMahon, S., Nagai, K., Perez-Rodriguez, E., Rozanov, A., Vacek, V., and Vitek, M.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: IEEE Transactions on Nuclear Science
• ISSN: 0018-9499
• ISSN (Online): 1558-1578
• Published Online: 09 October 2012