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.

Systems, devices and methods for inspecting and imaging of contents of a volume is disclosed. One implementation of the disclosed systems, devices and methods includes an apparatus for inspecting and imaging of contents of a volume of interest which includes a first particle tracking unit of detectors to receive incoming charged particles that transit through an object and to measure position and direction of the charged particles that transit through the object while allowing the charged particles to pass through, and a second particle tracking unit of detectors installed relative to the first particle tracking unit of detectors and to the volume of interest containing the object of inspection so that it is positioned to receive the outgoing charged particles that transit through the first particle tracking unit and transit through the object of inspection and to measure a position and a direction of the outgoing charged particles. The apparatus also includes a processor that processes information from the first and second particle tracking units of detectors to yield an estimate of a spatial map of atomic number and a density of the object. The methods disclosed here include triggering algorithms for signal selection, positional calibration algorithms for locating particle tracking units in absolute three dimensional coordinate space, and three-dimensional tomographic image reconstruction algorithms combining the tracking information from multiple pairs of particle tracking units.

A method for compensating a measurement deviation of a first scintillator and/or a photodetector of a radiometric fill level measuring device is provided, including detecting, by a second scintillator, radioactive emissions from the second scintillator; transmitting, in response to radioactive emissions, a first light signal from the first scintillator and a second light signal from the second scintillator, the first light signal being different from the second light signal; receiving, by the photodetector, the first light signal from the first scintillator and the second light signal from the second scintillator, and converting the light signals into electrical signals; comparing the electrical signals with deposited reference signals by means of a comparator; and adjusting the gain of the photodetector in response to comparing the electrical signals and stored reference signals. A radiometric fill level measuring device for fill level measurement, for density measurement, and/or for mass flow measurement is also provided.

A method for compensating a measurement deviation of a first scintillator and/or a photodetector of a radiometric fill level measuring device is provided, including detecting, by a second scintillator, radioactive emissions from the second scintillator; transmitting, in response to radioactive emissions, a first light signal from the first scintillator and a second light signal from the second scintillator, the first light signal being different from the second light signal; receiving, by the photodetector, the first light signal from the first scintillator and the second light signal from the second scintillator, and converting the light signals into electrical signals; comparing the electrical signals with deposited reference signals by means of a comparator; and adjusting the gain of the photodetector in response to comparing the electrical signals and stored reference signals. A radiometric fill level measuring device for fill level measurement, for density measurement, and/or for mass flow measurement is also provided.

A method for searching for and detecting gamma radiation sources in conditions of nonuniform radioactive contamination is provided. Stages in which a source of maximally active radiation is determined, the radiation power is measured with a collimated detector and at the same time the distance to the source is determined with the aid of a laser detector rangefinder. Readings of the laser rangefinder and the value of a dose rate are established by the detector are recorded. The dose rate of the radiation of the actual source is calculated, after which, to verify the distance measured to the radiation source, the aiming axis of the rangefinder is moved for a distance horizontally. The measurement is repeated and the distance recorded. The results of successive measurements of the distance are compared. If there is a divergence in the measurements within the laser rangefinder error limits, the information is acknowledged as reliable.

A method for searching for and detecting gamma radiation sources in conditions of nonuniform radioactive contamination is provided. Stages in which a source of maximally active radiation is determined, the radiation power is measured with a collimated detector and at the same time the distance to the source is determined with the aid of a laser detector rangefinder. Readings of the laser rangefinder and the value of a dose rate are established by the detector are recorded. The dose rate of the radiation of the actual source is calculated, after which, to verify the distance measured to the radiation source, the aiming axis of the rangefinder is moved for a distance horizontally. The measurement is repeated and the distance recorded. The results of successive measurements of the distance are compared. If there is a divergence in the measurements within the laser rangefinder error limits, the information is acknowledged as reliable.

A device for measuring large-area radioactive surface contamination can simultaneously obtain a plurality of detection values. The measurement device includes a frame body having a plurality of holes; a mover that is connected to, and moves, the frame body; and a plurality of radiation detectors that rest in the plurality of holes. The detectors detect one or more of: alpha rays, beta rays, or gamma rays. The location and level of radioactive contamination are accurately identified according to a comparison of the detection values of the plurality of radiation detectors.

A device for measuring large-area radioactive surface contamination can simultaneously obtain a plurality of detection values. The measurement device includes a frame body having a plurality of holes; a mover that is connected to, and moves, the frame body; and a plurality of radiation detectors that rest in the plurality of holes. The detectors detect one or more of: alpha rays, beta rays, or gamma rays. The location and level of radioactive contamination are accurately identified according to a comparison of the detection values of the plurality of radiation detectors.

A device providing high-accuracy, high-speed detection of fissile materials, the device comprising two coaxially arranged cylinders: an inner cylinder made of lead, which acts as a gamma shield and as a neutron multiplier; and an outer cylinder made of polyethylene, which acts as a neutron thermalizer. A pedestal capable of vertical axial movement is disposed in the lower part of the inner cylinder. Fifteen helium-3 counters with cadmium filters can be built into the wall of the outer cylinder in a circle, parallel to the generatrix. An isotropic deuterium-tritium 14 MeV neutron generator can be mounted in the wall of the outer cylinder, perpendicular to the generatrix. In one aspect, before installation, a vessel and a structural material contained therein are subjected to gamma scanning. Then, using the movable pedestal, the vessel is mounted in the inner cylinder so the center of mass of the structural material is opposite detectors.