Abstract A radiation survey meter including a radiation detector, an operational amplifier and a current meter in the output circuit thereof wherein the counting loss error of the detector, which causes a reduction in current at high dose rate levels, is compensated for by means of a Zener diode connected in circuit with a resistive network in the output circuit of the operational amplifier. For higher radiation dose levels, the output voltage of the operational amplifier exceeds the voltage at which the Zener diode starts conducting. The resulting impedance change in the output circuit causes additional current flow in the current meter. By proper selection of a Zener diode and the resistance network associated therewith, the dead time effect of the radiation detector can be adequately compensated for.
Inventors
👤 Joseph C Nirschl
👤 G Edgar Mooney Jr
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-30 15:14
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
36 words
A radiation survey meter as recited in claim 1 wherein said current meter is connected in series with an adjustable calibration resistive means and said compensating network is connected in shunt with said calibration resistive means.
Claim 2
Dependent Claim
174 words
A radiation survey meter comprising a nuclear radiation detecting means for producing pulses at a rate dependent upon the radiation dose rate, said detecting means being characterized by a counting loss at high levels of radiation dose rate, an operational amplifier for amplifying the pulses generated by said detecting means and producing a current in the output circuit thereof which is representative of the pulse repetition frequency of said detecting means, an indicating current meter through which said output current flows for indicating the radiation dose rate, a compensating network connected in the aforesaid output circuit for increasing the current flow through said meter when the output voltage of said amplifier exceeds a predetermined value, said compensating network including a resistive means and a Zener diode, said Zener diode being rendered conducting when said predetermined voltage level is atTained, a calibration resistor in circuit with said indicating meter, and a resistor connected between the junction of said Zener diode and said resistive means and the junction of said calibration resistor and said indicating meter.