A method of determining a quantity of a first radioisotope in a source term, disintegrating into a second radioisotope, the radioisotopes respectively emitting first and second gamma rays screened by the source term, the method comprising the steps: a) determining the theoretical ratio of counts between the first and second rays emitted in the absence of screening; b) measuring the net counts associated with the first and second rays emitted by the first and second radioisotopes; c) determining the screening rates of the first and second rays by the source term based on the ratio obtained in step a) and the counts obtained in step b); d) determining the quantity of the first radioisotope based on the screening rate of either the first or the second ray determined in step c).

System and methods for calibrating gamma ray tools using blanket field calibrator models is provided. A counting rate of a first gamma ray tool is simulated based on a model of a first blanket calibrator. When it is determined that the simulated counting rate matches a measured counting rate associated with the first gamma ray tool, a tally multiplier and a corresponding material specification for the model of the first blanket calibrator is determined. A counting rate for a second gamma ray tool is simulated based on the tally multiplier and the material specification determined for the model of the first blanket calibrator. A sensitivity factor for the second gamma ray tool is determined based on the simulation. The second gamma ray tool is calibrated according to a nominal blanket activity calculated from the sensitivity factor of the second gamma ray tool.

System and methods for calibrating gamma ray tools using blanket field calibrator models is provided. A counting rate of a first gamma ray tool is simulated based on a model of a first blanket calibrator. When it is determined that the simulated counting rate matches a measured counting rate associated with the first gamma ray tool, a tally multiplier and a corresponding material specification for the model of the first blanket calibrator is determined. A counting rate for a second gamma ray tool is simulated based on the tally multiplier and the material specification determined for the model of the first blanket calibrator. A sensitivity factor for the second gamma ray tool is determined based on the simulation. The second gamma ray tool is calibrated according to a nominal blanket activity calculated from the sensitivity factor of the second gamma ray tool.

A coded mask apparatus is provided for gamma rays. The apparatus uses nested masks, at least one of which rotates relative to the other.

A coded mask apparatus is provided for gamma rays. The apparatus uses nested masks, at least one of which rotates relative to the other.

A system is provided for correlating gamma spectrometry measurements and alpha spectrometry measurements of a same sample comprising radionuclides. The system includes at least a gamma detector able to provide gamma spectrometry measurements; an alpha detector able to provide alpha spectrometry measurements, equipped with a collimation grid; and means for acquiring and analysing alpha spectrometry and gamma spectrometry measurements.

Provided herein are neutron-based detection systems and methods that provide, for example, high throughput analysis of elemental analysis of scrap materials. Such systems and methods find use for the commercial-scale evaluation of bulk process materials where hazardous or otherwise undesirable materials or high value materials may be interspersed with the primary process material. In certain embodiments, the system is used to detect and potentially remove unexploded ordinance (UXO) from a conveyor of demilitarized shell casings being recycled by detecting the presence of nitrogen and other elements present in the UXO. In other embodiments, the system detects and removes unwanted or highly valuable materials from a stream of scrap material.

The present invention relates to a method for the quantification of radionuclides in liquid media comprising measuring a gamma-ray spectrum, a device for the quantification of radionuclides in liquid media and the use for the quantification of radionuclide concentrations in hydrometallurgical processing media, especially the quantification of uranium and/or radioactive uranium decay product concentrations in uranium mining solutions or in uranium recovery solutions or the quantification of thorium and/or radioactive .sup.232Th decay products in rare-earth element processing solutions.

The present invention relates to a method for the quantification of radionuclides in liquid media comprising measuring a gamma-ray spectrum, a device for the quantification of radionuclides in liquid media and the use for the quantification of radionuclide concentrations in hydrometallurgical processing media, especially the quantification of uranium and/or radioactive uranium decay product concentrations in uranium mining solutions or in uranium recovery solutions or the quantification of thorium and/or radioactive .sup.232Th decay products in rare-earth element processing solutions.

A method of detecting radon may include starting a first timer at a radon detection device in response to a first triggering action. A seal of the radon detection device may transition to a seal position from an open position in response to the first timer being equal to a measurement interval. The open position may facilitate the introduction of ambient air to a vent of the radon detection device. The seal position may discourage introduction of the ambient air to the vent. The vent may be in fluid communication with a test material. The test material may collect radon from the ambient air introduced to the radon detection device. A second timer may be started in response to the seal transitioning from the open position to the seal position. The seal remains in the sealed position following the transition from the open position to the sealed position.