Abstract:
The Beckman Helium Discharge Detector has been found to be
sensitive to the fixed gases oxygen, nitrogen, and hydrogen
at detection levels 10-100 times more sensitive than possible
with a Bow-Mac Thermal Conductivity Detector. Detection
levels o~ approximately 1.9 E-4 ~ v/v oxygen, 3.1 E-4 ~ v/v
nitrogen, and 3.0 E-3 ~ v/v hydrogen are estimated. Response
of the Helium Discharge Detector was not linear, but is
useable for quantitation over limited ranges of concentration
using suitably prepared working standards. Cleanliness of
the detector discharge electrodes and purity of the helium
carrier and discharge gas were found to be critical to the
operation of the detector. Higher sensitivities of the
Helium Discharge Detector may be possible by the design and
installation of a sensitive, solid-state electrometer.
