A radiation detector can include a scintillator having opposing end surfaces and a plurality of discrete photosensors disposed on an end surface of the scintillator. In an embodiment, the photosensors are disposed at the corners or along the peripheral edge of the end surface, as opposed to being disposed at the center of the end surface. In an embodiment, the plurality of discrete photosensors may cover at most 80% of a surface area of the end surface of the scintillator and may not cover a center of the end surface of the scintillator. In a further embodiment, an aspect ratio of the monolithic scintillator can be selected to improve energy resolution.

A detection substrate and a manufacturing method thereof, and a detector are provided. The detection substrate comprises a base substrate, a thin film transistor, a PIN photodiode and a scintillation layer. The thin film transistor and the PIN photodiode are provided above a first face of the base substrate and the scintillation layer is provided above a second face of the base substrate. The visible light obtained after the X-ray passes through the scintillation layer is directly irradiated on the PIN photodiode after passing through the base substrate with relative high transmittance, thus preventing intensity of the light irradiated on the PIN photodiode from being weakened, and improving light utilization efficiency of the detection substrate.

According to an embodiment, a signal processor includes an integrator, a differentiator, a zero cross detector, a pile-up detector, an event interval detector, a counter, and a creator. The integrator is configured to calculate charge of current from a photoelectric converter for an incident radiation. The differentiator is configured to calculate a differential value of the current. The zero cross detector is configured to detect a zero cross of the differential value. The pile-up detector is configured to detect pile-up of the current based on the zero cross. The event interval detector is configured to detect, based on the zero cross and pile-up, an event interval of the radiation entering. The counter is configured to count, based on the charge and pile-up, the respective numbers of events according to the charge and the event interval. The creator is configured to create histograms for the numbers of events.

A SiPM readout circuit includes a front-end circuit having amplifiers coupled to SiPM analog outputs, pixel readout channels coupled to amplifiers provide a timing signal representing gamma ray photon detection in individual SiPM, a block timing channel that creates a summed signal from all SiPMs, and generates a block timing signal and a validation signal, an energy channel that generates a summed energy signal and a two-dimensional position of the gamma ray photon detection in the block, and a control logic/processing circuit that performs a time stamp estimation method. Methods of determining the radiation event timing and a non-transitory computer-readable medium containing computer-readable instructions to implement the methods are disclosed.

A semiconductor photomultiplier (SPM) device is described. The SPM comprises a plurality of photosensitive elements, a first electrode arranged to provide a bias voltage to the photosensitive elements, a second electrode arranged as a biasing electrode for the photosensitive elements, a plurality of quench resistive elements each associated with a corresponding photosensitive element, a plurality of output loads each having a capacitive load operably coupled to a resisitive load in a parallel configuration between first and second nodes; each first node is common to one of the photosensitive elements and the corresponding quench element; and a third electrode coupled to the second nodes of the output loads to provide an output signal from the photosensitive elements. The outputs loads fully or partially correct an overshoot of an output signal on the third electrode.

Techniques are provided for x-ray image data monitoring and signaling for patient safety. A methodology implementing the techniques according to an embodiment includes integrating energy associated with a received x-ray pulse at an array of pixels. The method also includes multiplexing a readout of the integrated energy from the array of pixels, as analog signals, into channels, and performing analog to digital conversion of the analog signals of the channels into digital signals. The method further includes generating an error indicator in response to determining that a calculated mean of the digital signals is either greater than an upper threshold value associated with saturation or less than a lower threshold value associated with underexposure. The method further includes transmitting the error indicator over a Universal Serial Bus, to an imaging system, to terminate transmission of further x-ray pulses.

A positron emission tomography (PET) photosensor output circuit configured to be operably coupled to a PET photosensor system is provided that includes a plurality of regional circuit portions and a summing portion. Each regional circuit portion is configured to be operably coupled to a corresponding photosensor system region and includes an input portion, a first branch, and a second branch. The first branch includes a delay unit and a switch. The second branch includes a sensor unit configured to place the switch in a closed position when a signal received via the input portion satisfies a threshold and to place the switch in an open position when the signal received via the input portion does not satisfy the threshold. The summing portion is configured to receive corresponding regional circuit outputs from the regional circuit portions, and to combine the regional circuit outputs to provide a summed output.

According to an embodiment, an apparatus includes a first detector, a second detector, and a controller. The first detector is configured to detect first radiation at a first frequency within a first time by at least a first radiation detecting element and a second radiation detecting element that are positioned near to each other, and output a first signal. The second detector is configured to detect second radiation at a second frequency less than the first frequency within a second time by at least the first radiation detecting element and the second radiation detecting element, and output a second signal. The controller is configured to generate a third signal representing a difference between the first signal and the second signal, and calculate energy using the third signal.

A method of operation of a scintillator detector comprising a scintillator and a photodetector is described, together with a device embodying the method. The method comprises the steps of: periodically producing a light pulse; impinging at least some of the light from a successive plurality of such light pulses onto a light-receptive part of the photodetector; measuring the electrical response of the photodetector; processing the electrical response of the photodetector to determine a pulse height and a variance of pulse height; numerically processing the pulse height and variance of pulse height so determined to obtain at least a first data item characteristic of the response of the photodetector. The method additionally or alternatively comprises the steps of: periodically producing a light pulse including light in the ultraviolet spectrum; impinging at least some of the UV light from a successive plurality of such light pulses onto a light-receptive part of the scintillator; inducing photon emission in the scintillator in the visible spectrum; measuring the electrical response of the scintillator; processing the electrical response of the scintillator to obtain at least a data item characteristic of the response of the scintillator; and optionally verifying the electrical response of the scintillator by comparing at least the said data item against a predetermined reference response; and optionally additionally or alternatively outputting a control signal to the photodetector, which signal is modified in part responsive at least to the value of the said data item.

A multi-channel system for truck scanning, includes an impulse radiation source; and a plurality of detection circuits, each detection circuit comprising a scintillator, a photodiode, a supplemental circuit, an integrator and an ADC, connected in series. A current of the photodiode is proportional to radiation from the impulse radiation source. A data storage device stores outputs of the ADCs and provides the outputs to a computer that converts them to a shadow image of the scanned truck. The supplemental circuit isolates a capacitance of the photodiode from the integrator, filters out low frequency signals from the photodiode, amplifies the signal from the photodiode and reduces a bandwidth of the photodiode seen by the integrator. The supplemental circuit reduces an influence of capacitance of the photodiode on system noise, increases a signal-to-noise ratio of the system, and reduces an influence of photodiode temperature changes on a quality of the scanned image.