Variable pressure and temperature liquid nitrogen cryostat for optical measurements with applied electric fields


Swaffield, D.J., Lewin, P.L., Chen, G. and Swingler, S.G. (2004) Variable pressure and temperature liquid nitrogen cryostat for optical measurements with applied electric fields. Journal of Measurement Science and Technology, 15, (11), 2325-2332. (doi:10.1088/0957-0233/15/11/019).

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Description/Abstract

A cryostat with a high-voltage bushing, optical observation ports, variable controlled temperature and pressure has been designed to further the study of liquid nitrogen as a dielectric medium. The novelty in this design lies in the simultaneous achievement of these functions in a single design with a sufficiently large vessel to accommodate realistic geometries for high temperature superconducting cable termination prototypes. In addition, a commercial single-stage helium expander cryo-cooler is integrated into the apparatus to achieve steady state temperatures down to 63.5 K, without the need for sacrificial loss of liquid nitrogen to maintain vessel temperature. The cryostat inner vessel is certified for operating up to 2 MPa. A custom-made filled-resin bushing provides an electrical feed-through rated to 76.2 kV ac. For optical measurements with a range of sample geometries four optical ports are incorporated into the vessel utilizing sapphire windows and indium seals to form the inner pressure vessel. A technique employing a copper-vapour laser light source and high-speed digital camera for stroboscopic image capture of density change streamers and bubble dynamics with synchronized collection of electrical discharge data has been developed. This design has been used to study pre-breakdown phenomena, bubble dynamics with applied electrical fields and electrical breakdown. General construction, mode of operation and initial results are presented.

Item Type: Article
ISSNs: 0957-0233 (print)
Subjects: Q Science > QA Mathematics > QA75 Electronic computers. Computer science
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Faculty of Physical Sciences and Engineering > Electronics and Computer Science > EEE
ePrint ID: 260042
Date Deposited: 22 Oct 2004
Last Modified: 27 Mar 2014 20:02
Publisher: Institute of Physics Publishing
Further Information:Google Scholar
ISI Citation Count:2
URI: http://eprints.soton.ac.uk/id/eprint/260042

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