Characterisation of analogue front end and time walk in CMOS active pixel sensor

In this work we investigated a method to determine time walk in an active silicon pixel sensor prototype using Edge-TCT with infrared laser charge injection. Samples were investigated before and after neutron irradiation to 5· 10^14n_ eq/cm^2. Threshold, noise and calibration of the analogue front end were determined with external charge injection. A spatially sensitive measurement of collected charge and time walk was carried out with Edge-TCT, showing a uniform charge collection and output delay in pixel centre. On pixel edges charge sharing was observed due to finite beam width resulting in smaller signals and larger output delay. Time walk below 25 ns was observed for charge above 2000 e^- at a threshold above the noise level. Time walk measurement with external charge injection yielded identical results.

Design and Penetration Performance of Annular Shaped Charge Structure

Based on the principle of the equivalent momentum of the corresponding elements for internal and external liners, annular shaped charge structure is proposed. The generatrix analytical equations for the external surfaces of the external liner and external charge are deduced. Experimental and numerical studies are conducted to investigate the formation and penetration process of the jet for the annular shaped charge under different initiation radiuses, and the initiation radius corresponding to the detonation wave front matched with the liner is optimized. At this radius, shaped charge can form an ideal cylindrical jet. Moreover, the diameter of the jet approximates the theoretical diameter of the jet, and has satisfactory symmetry and focus.