title: Continuous ammonia monitor using a Stark microwave cavity resonator.
abstract: An ammonia monitor has been made by using a rectangular Stark microwave cavity tightly coupled through an iris to a Gunn oscillator. The Stark electrode installed inside the cavity is provided with a 100 kHz sinusoidal modulation voltage and a dc sweep voltage. The oscillation of the Gunn diode is tuned with the coupled Stark cavity to a frequency near a J,K=3,3 transition (23870.1 MHz) of ammonia. By fixing the Stark dc bias to a voltage which gives a peak intensity of the derivative output of the electric-resonance signal, ammonia is continuously monitored. An extremely good long-term stability is obtained. The noise level corresponds to 0.08 ppm of ammonia.
authors.affiliation: Sagami Chemical Research Center, Nishi-Ohnuma, Sagamihara-shi, Kanagawa 229, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Uehara
authors.forename: Y
authors.initials: Y
authors.lastname: Ijuuin
authors.forename: Y
authors.initials: Y
authors.lastname: Morino
authors.forename: T
authors.initials: T
authors.lastname: Kamidate
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Imai