Closed-loop pulsed helium ionization detector

Patent · Mon Nov 09 23:00:00 EST 1987

OSTI ID:5731337

Ramsey, R S; Todd, R A

In combination, a helium ionization detector and a closed-loop control system for pulsed operation of the helium ionization detector is described comprising: a helium ionization detector having an anode and cathode electrodes between which a helium carrier gas containing an ionizable component whose concentration is to be detected is introduced to be ionized to produce an ionization current therein which flows through the electrodes when a high voltage bias is applied between the electrodes; a high voltage pulser means for generating and applying selected amplitude high voltage bias pulses; a reference current generator means for generating a selected reference current corresponding to a desired average ionization current in the detector; an electrometer circuit means for generating an output signal at an output terminal that varies in inverse proportion to the change in ionization current in the detector; a switching pulse generating means responsive to the output signal of the electrometer circuit means for generating and applying the switching pulses to the high voltage pulser means at a frequency and a selected duty cycle which maintains a constant average ionization current flowing in the detector; means for sensing the amplitude of the output of the electrometer circuit means as an indication of the concentration of the ionizable component being detected by the helium ionization detector.

• Assignee: Dept. of Energy, Washington, DC
• Patent Number(s): US 4705948
• OSTI ID: 5731337
• Country of Publication: United States
• Language: English

Related Subjects

440101* -- Radiation Instrumentation-- General Detectors or Monitors & Radiometric Instruments
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AMPLIFIERS
CLOSED-LOOP CONTROL
CONTROL
DESIGN
ELECTRODES
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FLUIDS
FUNCTION GENERATORS
GASES
HELIUM
HIGH-VOLTAGE PULSE GENERATORS
IONIZATION
IONIZATION CHAMBERS
MEASURING INSTRUMENTS
NONMETALS
OPERATION
PULSE CIRCUITS
PULSE GENERATORS
RADIATION DETECTORS
RARE GASES
TRIGGER CIRCUITS