Design Of Photon Counting Linear Array Readout Circuit Based On Adaptive Sampling

Photon counting imaging technology can obtain 2D image information of the target scene by using single photon detector to sample it with high accuracy.Single photon counting detection is widely used in such areas as defense early warning,power grid security monitoring,quantum information and medical imaging for its high sensitivity,high signal to noise ratio,and good time stability.However,with the continuous in-depth study of contemporary detection technology and information processing technologies,higher requirements have been placed on the detection efficiency,detection accuracy,and sensitivity of single photon detection systems.In order to meet the demand of high-voltage corona leakage detection,an adaptive sampling detection photon counting linear array readout circuit is proposed,which can accurately measure the weak UV radiation photon intensity information of the target object.The readout circuit uses a passive sampling mode in which photon triggers avalanche and automatically quenches,which determines the sampling and quenching time sequence from the photon distribution,and can obtain the time-series distribution characteristics consistent with the random distribution of photons for weak light detection.The Hold-off time is automatically regulated by adding a processing unit inside the readout circuit,which dynamically adjusts the delay time of the next frame according to the number of photons of the current detection frame.Under the premise of ensuring that most photons are correctly detected,the time for the APD detector to be tested is reduced,so as to reduce the number of false counts introduced by the dark counts and the afterpulses.On this basis,the circuit design and pixel array layout are completed.Finally,combined with the testability requirements of the chip,the circuit and layout design of the free-running detection system were completed.Using TSMC 0.18?m MS technology,the simulation of the adaptive sampling photon counting readout circuit and MPW taper verification are completed.The array size is 1×8,and the total area of the readout circuit is 1634?m×995?m.The simulation results meet the design requirements.The chip test results show that the modules of the adaptive sampling system can work properly,and there is independency on the dead-time adjustment between each pixel,which can maximize the overall linear array performance.The increase in light intensity will cause the detection efficiency to decrease.The system automatically compensates for the loss of detection efficiency by automatically reducing the dead time.The dark count rate is less than 8kcps,the dynamic range is 36.12 dB,the dead time adjustable range is 0.1?s~204.8?s,and the power consumption is 2.9mW.With the cooperation of the optical imaging instrument,the scanning imaging of the target ultraviolet light source is realized.The UV single photon detection system developed in this paper can be applied to the condition monitoring of high-voltage electrical equipment,and it also has potential application value in near-field surveying,reconnaissance,ship and aircraft three-dimensional digital vision.