Abstract: 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.

Abstract: 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.