Research On Time-correlated Single Photon Counting Techniques Based On MCP Position Sensitive Anode Detector

Currently, Time-correlated single photon counting technology (TCSPC) has madea great progress，has been developed into a fast, multi-dimensional optical recordingtechnology and widely used in fluorescence lifetime imaging, diffuse opticaltomography, time-resolved fluorescence microscopy, laser radar and ultra-sensitivetime-resolved spectral measurements. The high-precision optical scanningcomponents are required when TCSPC used for imaging detection or spectralmeasurements. Due to long scan time, real-time imaging is limited, and the time andspatial resolution is not high. This paper focused on this problem, and proposed todeveloped MCP position sensitive anode detector with array structure, the electronicssystems, and the data processing software to achieve continuous，simultaneousmeasurement of arrival time and location of single photon, and explore the applicationin the time-resolved photon counting imaging, the pulse profile detection of veryweak X ray and the random number extraction. The main research contents andresults are as follows:(1) The principle of TCSPC, research advances and applications in related fields areinvestigated. The key technology of TCSPC system, including single-photon detector,pre-amplification techniques, charge measurement techniques, timing and time-digitalconverter techniques were described in detail. The program of simultaneousmeasurement system of arrival time and location of photon based on MCP positionsensitive anode single photon detector is proposed;(2) The MCP position sensitive anode single detectors are designed and developed.The detector is designed as charge directly collected structure, use "V" or the "Z"-typecascade MCP to multiply electron, and read out by charge distribution anode, theVernier anode and WSZ anode. Charge-sensitive preamplifier and shaping amplifierare chose as the front end electronics;(3) The electronic system used for simultaneous measurement of arrival time and location of single photon is designed and developed. In the electronic system, thearrival times of photon sequence relative to a common start time is measured bycombing coarse time and fine time. A high stability OCXO clock is counted tomeasure the coarse time and a high resolution FPGA-based carry chain TDC is usedto measure the fine time. The photon arrival timing signal is used to set upsynchronization, on the one hand the timing signal is used to determine the arrivaltime of photon, on the other and, the timing signal trigger peak acquisition after adelay. The amplitudes of multi-channel pulse are measured by triggering sample afterpeak hold and each single-photon pulse sample only one point. The timing circuit ofarrival photon firstly sums up multi-channel pulses into one pulse, and then generatestiming signal by the constant fraction timing methods with threshold discriminationfunction. The data of photon arrival times and locations is transmitted to computer bymemory switching technology and an usb2.0interface. The electronic properties testresults shows that the multi-channel pulse peak acquisition accuracy is20mV, thetiming accuracy of photon arrival is0.95ns, time measurement accuracy is500ps, thedead time of electronic system is100ns and the maximum average count rate is2.67Mcps, maximum recording time is6.11hours;(4) A time-resolved photon counting imaging system is set up using thesimultaneous measurement system of arrival time and location of photon based onMCP position sensitive anode detector. Time-resolved photon counting imagingtheoretical model is derived based on the MCP position sensitive anode detector.Software has been developed to achieve the function including data acquisitioncontrol, data preprocessing, data analysis, position decoding, and image synthesis.The time-resolved image of the very weak optical radiation can be reconstructed byimage processing. According to test, the space resolution is superior to100mμ withVernier anode and80mμ with WSZ anode, time resolution is superior to1.53ns；(5) An optical quantum random number generator is set up using the simultaneousmeasurement system of arrival time and location of photon based on MCP WSZanode detector. A space encoding method is proposed to extract random number basedon the space randomness of arrival photon. Three different kinds of method are proposed to extract random number based on the time randomness of arrival photon.First, the number of photons detected in parity time interval is proposed to extractrandom number. Second, continuously comparing the time intervals between twoadjacent detected photons is proposed to extract random number. Third, a kind of timeencoding method is proposed to extract random number. The random numbersgenerated by above four methods are tested by software ENT. Test results show all ofrandom numbers have a good randomness, do not require post-processing and fullymeet the standards of true random numbers.