Study On Crosstalk Optimization And Timing Performance Of Small Cell 3D Detectors

With the upgrade of the Large Hadron Collider,the standard inner pixel detector with a two-dimensional planar electrode structure will be exposed to a strong radiation environment,and the performance of the detector will be seriously degraded.The three-dimensional trench detector has strong anti-irradiation ability,fast collection speed,and low working voltage.It has good application prospects as the innermost pixel detector of the Large Hadron Collider.Based on the three-dimensional trench electrode detector,the crosstalk between adjacent cells of the pixel detector is analyzed,a novel three-dimensional double-sided combination trench electrode detector is proposed,and the timing performance of the three-dimensional trench electrode detector is studied.First,the crosstalk between the detector cells is studied,which is conducive to the selection of the threshold parameters of the detector and improves the pixel resolution.By deriving the Ramo formula,the signal collection of the detector is analyzed,and the effects of different electrode spacing,working voltage and incident position on the crosstalk between detector cells are studied.It is found that the higher the working voltage,the greater the crosstalk current signal,and the more crosstalk collected charges;the closer the particle incident position is to the trench electrode,the more crosstalk collected charges,but the amount is less than 200 e^-;the electrode spacing has little effect on charge collection.Second,a novel three-dimensional double-sided combination trench electrode detector is proposed.In order to prove the advantages of the structure,the electric field distribution and the crosstalk current were compared with the traditional detector.It is found that the bottom electric field distribution of the three-dimensional double-sided combination trench electrode detector is more uniform,the working voltage is 60 V,and the crosstalk current between the cells is reduced by about 10times compared with the traditional three-dimensional trench electrode detector.Third,the factors affecting the time resolution of the detector are analyzed,and an ultra-fast three-dimensional trench electrode detector is designed.The working voltage,electric field,leakage current,capacitance and current signals of the three-dimensional trench electrode detector with electrode spacing of 5?m and 10?m are analyzed by simulation.It is found that the working voltage of the detector corresponding to the electrode spacing is 7 V and 18 V,and the capacitance is 56 f F and 37 f F respectively.After 2×10¹⁶n_eq/cm²irradiation,the leakage current increases from the order of 10^-12A to the order of 10^-8A,the electric field distribution is more uniform,and the low electric field area is reduced.the irradiation has little effect on the current signal,under the working voltage,the current signal rise time is about 25ps,and the signal duration is about 0.4 ns.