Operation of cold-cathode gauges in high magnetic fields

Conference · Mon Nov 11 04:00:00 EST 1985

OSTI ID:6324575

Thomas, Jr, S R; Goerz, D A; Pickles, W L

The Mirror Fusion Test Facility (MFTF-B), under construction at LLNL, requires measurement of the neutral gas density in high magnetic fields near the plasma at several axial regions. This Background Gas Pressure (BGP) diagnostic will help us understand the role of background neutrals in particle and power balance, particularly in the maintenance of the cold halo plasma that shields the hot core plasma from the returning neutrals. It consists of several cold-cathode, magnetron-type gauges stripped of their permanent magnets, and utilizes the MFTF-B ambient B-field in strengths of 5 to 25 kG. Similar gauges have operated in TMX-U in B-fields up to 3 kG. To determine how well the gauges will perform, we assembled a test stand which operated magnetron gauges in an external, uniform magnetic field of up to 30 kG, over a pressure range of 1E-8 T to 1E-5 T, at several cathode voltages. This paper describes the test stand and presents the results of the tests.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6324575
• Report Number(s): UCRL-92741; CONF-851174-22; ON: DE86003489
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BAYARD-ALPERT GAGES
CONTAINERS
HIGH VACUUM
IONIZATION GAGES
MAGNETIC MIRRORS
MEASURING INSTRUMENTS
MFTF DEVICES
NEUTRAL PARTICLES
OPEN PLASMA DEVICES
PARTICLES
PERFORMANCE TESTING
PRESSURE GAGES
PRESSURE VESSELS
TESTING
THERMONUCLEAR DEVICES
VACUUM GAGES