AVS 46th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuP

Paper VT-TuP5
New-type Leak Detector utilizing Oxygen-Ion Conductor (I) --Principle and Fundamental Performances--

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: K. Tatenuma, KAKEN Co., Japan
Authors: K. Tatenuma, KAKEN Co., Japan
K. Uchida, KAKEN Co., Japan
K. Uta, KAKEN Co., Japan
T. Noguchi, KAKEN Co., Japan
H. Saeki, Japan Synchrotron Radiation Research Institute
A. Ando, Himeji Institute of Technology, Japan
T. Momose, Miyagi National College of Technology, Japan
Correspondent: Click to Email
We developed a new-type leak-detector [LeakD] with an extraordinary wide pressure range by electrochemical measurement of a partial oxygen pressure utilizing the character and performance of oxygen-ion conducting ceramics, e.g. Yttria Stabilized Zirconia (YSZ). Tests using a vacuum apparatus composed of LeakD, a residual gas analyzer (RGA), a capacitance manometer, a Penning gauge, and a turbomolecular pump, confirmed that the responces of LeakD follows Nernst's law; e.m.f.=RT/nF[ln(P(O@sub 2@)ref/P(O@sub 2@)vac)], where e.m.f.: electromotive force (V), R: gas constant (8.314 J/molxK), T: temperature of probe (K), n: charge number of ionization (4: 2O@super 2-@), F: Faraday constant (9.65x10@super 4@ C/mol), P(O@sub 2@)ref and P(O@sub 2@)vac are oxygen partial pressures at a standard gas and a vacuum, respectively. An oxygen partial pressure in a vacuum is decided from e.m.f. LeakD is simple and small, which composed of YSZ ceramics tube (od.10 mm x id.7 mm x 90 mm (long), sealed at one ended) with porous platinum electrodes on inner and outer surfaces, a heater inserted into the YSZ tube to gain a high oxygen-ion conducting rate, a thermocouple, and two electric wires to measure the e.m.f. between two electrodes. To look for a leak point using LeakD, a gas excluded oxygen, e.g. nitrogen and so on, is blown to a point. LeakD is basically a general oxygen sensor using an oxygen-ion conductor. LeakD can detect a partial oxygen pressure by a function in the ranges from 10@super +2@ to 10@super -20@ atm or less; especially it has detectable leak rate both larger and smaller than He leak rate of RGA.