Instruction manual for a microwave ammonia monitor

Technical Report · Mon Jun 13 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/7220798· OSTI ID:7220798

Hrubesh, L. W.

The microwave ammonia monitor is a self contained (the vacuum pump is external) microwave rotational spectrometer that selectively detects and monitors ammonia vapor in air. A solid-state oscillator is used as the microwave source and a microwave cavity made from waveguide provides a chamber for the sample analysis. The air sample is continuously flowed through the waveguide cavity so that changes in the trace concentration of ammonia in air can be determined. The principle of operation of the microwave ammonia monitor is based on the absorption of microwave radiation by a vibration-rotation quantum transition of the ammonia molecule. Ammonia absorbs microwave radiation in a very narrow frequency range with its peak at 23,870.18 MHz. The microwave source is electronically controlled to oscillate only at this frequency and to provide a very stable output power. Thus, even a very small amount of microwave power that is absorbed by the ammonia gas is detectable and no other gas in the air sample is known to absorb any microwave radiation within the frequency output band of the oscillator. The specifications, operation, and maintenance procedures are described. Also a parts list and engineering drawings are included. (WHK)

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7220798
• Report Number(s): UCID-17503
• Country of Publication: United States
• Language: English

Related Subjects

440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABSORPTION SPECTROSCOPY
AIR POLLUTION MONITORS
AIR SAMPLERS
AMMONIA
CAVITIES
DESIGN
DIAGRAMS
DOCUMENT TYPES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
HYDRIDES
HYDROGEN COMPOUNDS
LABORATORY EQUIPMENT
MAINTENANCE
MANUALS
MICROWAVE RADIATION
MICROWAVE SPECTRA
MONITORING
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OPERATION
OSCILLATORS
RADIATIONS
SAMPLERS
SPECIFICATIONS
SPECTRA
SPECTROSCOPY
TRACE AMOUNTS