A Geant4-based study on the origin of the sparks in a Micromegas detector and estimate of the spark probability with hadron beams
A Geant4 simulation of a Micromegas detector in hadron beams is presented. Very large energy deposits are observed, resulting from the production of highly ionizing particles in nuclear interactions of incoming hadrons with different parts of the detector. Assuming a spark is induced by a local, large energy deposit, we find that the spark rate grows as a power law with the gain of the detector, as observed experimentally. Using measurements with alpha particles, or alternatively the well known Raether limit, our simulation gives a correct estimate of the spark rate observed in hadron beams. A few experimental tests are proposed to check the validity of this simulation.
A sub-optimal Hinfin controller with the minimum entropy bound is designed by researching the characteristic of minimum entropy Hinfin optimal control in this paper. The controller which satisfies closed-loop minimum entropy can obtain an important tradeoff between the robustness of Hinfin controller and the performance of Hinfin controller. The augmented transfer function of generator excitation controller is developed for the single machine infinite bus (SMIB) power system. A new robust nonlinear excitation control strategy for SMIB power system is designed based on minimum entropy Hinfin, control. The simulation results show that the proposed minimum entropy Hinfin excitation controller improves system robustness on dynamic uncertainties, and suppresses the exogenous perturbation to the system. So the proposed approach can enhance dynamic stability of power system.