Abstract: A method and apparatus for discriminating the types of radiation interacting with an integrated radiation detector having of a pulse-mode operating photosensor which is optically coupled to a gamma-ray scintillator sensor and a neutron scintillator sensor and uses an analog to digital converter (ADC) and a charge to digital converter (QDC) to determine scintillation decay times and classify radiation interactions by radiation type. The pulse processing provides for, among other things, faithful representation of the true energy spectrum of the gamma radiation field and allows for radioisotope identification by searching for the presence of characteristic energy lines in the gamma energy spectrum. The pulse shape discrimination method ensures that the high sensitivity and resolution of the isotope identification function is not affected during operation in mixed neutron-gamma fields.

Abstract: A method of making a cubic halide scintillator material includes pressing a powder mixture of cubic halide and at least one activator under conditions of pressure, temperature, residence time and particle size effective to provide a polycrystalline sintered cubic halide scintillator having a pulse height resolution of from about 7% to about 20%. The conditions include a temperature ranging from about ambient temperature up to about 90% of the melting point of the cubic halide, a pressure of from about 30,000 psi to about 200,000 psi, a pressing residence time of from about 5 minutes to about 120 minutes and an average cubic halide particle size of from about 60 micrometers to about 275 micrometers.

Abstract: An array of position-sensitive avalanche photodiodes is provided in which output signal contacts from corners of each photodiode are grouped in common for readout. Each photodiode may be provided on a single wafer or chip, with photodiodes being separated by a trench or a groove. Corners of each photodiode include contacts for reading out signals resulting from gamma rays incident events in an adjacent scintillator. Grouping of the contacts into common output channels reduces the number of output channels, while still permitting localization of gamma ray incident events in the scintillator crystals. The photodiode array may be positioned adjacent to one face of a scintillator, with a photomultiplier tube to be positioned adjacent to another. The detector arrangement may be used for positron emission tomography imaging and similar techniques.

Abstract: A sensing element or detector activated by radiation comprising a first scintillator activated by gamma radiation; and a neutron sensing layer comprising a second scintillator activated by neutron radiation.

Abstract: A method for identifying localized optical emission is disclosed. The method involves identifying a region, which corresponds to a plurality of scintillator units of a scintillator, on a position sensitive photodetector that is impacted by one or more photons. The method further involves identifying a readout channel of a pixellated photodetector array that corresponds to a pixel associated with a scintillator unit impacted by the one or more photons. The method, further involves, identifying the scintillator unit based on the region and the readout channel.

Abstract: A method for localizing optical emission is disclosed. The method involves identifying a first readout channel of a first pixellated photodetector array based on an impact of a first photon on the first pixellated photodetector array. The first photon is emitted by a scintillator unit of a scintillator array and the first readout channel corresponds to a column of one or more pixels of the first pixellated photodetector array. The method also involves identifying a second readout channel of a second pixellated photodetector array based on an impact of a second photon on the second pixellated photodetector array. The second photon is emitted by the scintillator unit and the second readout channel corresponds to a row of one or more pixels of the second pixellated photodetector array. The method further involves identifying the scintillator unit based on the first readout channel and the second readout channel.

Abstract: An imaging system configured to provide improved position resolution is disclosed. The imaging system includes detector acquisition circuitry that is configured to acquire a plurality of rise-times and a plurality of amplitudes from a detector assembly that includes an array of one or more detector elements. The imaging system also includes position determining circuitry that is configured to determine a plurality of respective impact positions on each of the detector elements. The plurality of impact positions is based on at least the plurality of rise-times and the plurality of the amplitudes acquired by the detector acquisition circuitry.