Monitoring the output of a radiation generator
AssigneeSchlumberger Technology Corporation
InventorsSicco Beekman, Christian Stoller, Robert Arthur Adolph
Life of this patent
Estimating the term…
Abstract
A method is described for obtaining an accurate and precise value for radiation output of a radiation generator. Radiation is generated in the radiation generator, and the radiation output of the radiation generator is measured using a radiation monitoring device. An instantaneous inferred radiation output is determined from operating parameters of the radiation generator, and over a period of time a calibration factor between the measured and the instantaneous inferred radiation output is determined. The accurate and precise value for radiation output is determined from the instantaneous inferred radiation output and the determined calibration factor.
Claims20
A method for obtaining an accurate and precise value for radiation output of a radiation generator comprising:
- generating radiation in the radiation generator;
- measuring radiation output of the radiation generator using a radiation monitoring device;
- determining an instantaneous inferred radiation output from operating parameters of the radiation generator;
- determining over a period of time a calibration factor between the measured and the instantaneous inferred radiation output;
- and
- determining the accurate and precise value for radiation output from the instantaneous inferred radiation output and the determined calibration factor.
A method of operating a downhole tool in a borehole in a subsurface formation, the downhole tool comprising a radiation generator, an outgoing radiation monitor that operates during a first time interval but not during a second time interval, and at least one incoming radiation detector, the method comprising:
- generating radiation in the radiation generator;
- measuring outgoing radiation from the radiation generator into subsurface formation using the outgoing radiation monitor during the first time interval;
- determining an instantaneous inferred radiation output from operating parameters of the radiation generator during the first time interval;
- determining a calibration factor between the measured and the instantaneous inferred radiation output;
- determining the accurate and precise radiation output from the instantaneous inferred radiation output and the determined calibration factor;
- measuring incoming radiation from the subsurface formation using the at least one incoming radiation detector;
- and
- correlating the measured incoming radiation to the accurate and precise radiation output.
A downhole tool comprising:
- a neutron generator;
- a neutron monitor to measure neutron output of the neutron generator;
- processing circuitry coupled to the neutron generator and neutron monitor and configured to determine an instantaneous inferred neutron output from operating parameters of the neutron generator,
- determine over a period of time a calibration factor between the measured and the instantaneous inferred neutron output, and
- determine an accurate and precise neutron output from the instantaneous inferred neutron output and the determined calibration factor.
Dependencies are inferred from the claim text.