We study an intense beam propagating through the double periodic focusing channel by the particle-coremodel,and obtain the beam envelope equation.According to the Poincare-Lyapunov theorem,we analyze the stabilityof b...We study an intense beam propagating through the double periodic focusing channel by the particle-coremodel,and obtain the beam envelope equation.According to the Poincare-Lyapunov theorem,we analyze the stabilityof beam envelope equation and find the beam halo.The soliton control method for controlling the beam halo-chaos isput forward based on mechanism of halo formation and strategy of controlling beam halo-chaos,and we also prove thevalidity of the control method,and furthermore,the feasible experimental project is given.We perform multiparticlesimulation to control the halo by using the soliton controller.It is shown that our control method is effective.We alsofind the radial ion density changes when the ion beam is in the channel,not only the halo-chaos and its regeneration canbe eliminated by using the nonlinear control method,but also the density uniformity can be found at beam's centre aslong as an appropriate control method is chosen.展开更多
Measurement precision of laser displacement sensor is subject to various factors,among which laser jitter and target tilt will directly lead to the position movement and shape variation of the laser spot,resulting in ...Measurement precision of laser displacement sensor is subject to various factors,among which laser jitter and target tilt will directly lead to the position movement and shape variation of the laser spot,resulting in displacement measurement errors,so that researchers have to do a lot of research on the spot centering algorithm to weaken the above effects,which can treat the symptoms but not the root cause.Starting from the source of the problem,this paper proposes a double focus double peak solution,which uses a reflector to change the direction of the optical path,so that the imaging spots of the designed two optical paths focus on the same CMOS,forming a double peak structure.When laser jitter or target tilt occurs,the center of the two laser spots is shifted,but they move in the same direction,while their relative position remains unchanged.Therefore,the displacement can be characterized by the relative position of the two laser spots,so that laser jitter and target tilt are suppressed from the source.However,the two spots imaged on CMOS form a non-Gaussian distributed double peak structure,so the conventional laser spot centering algorithms are no longer applicable.To this end,a double peak adaptive threshold waveform extraction method combined with grayscale gravity method is proposed for spot centering algorithm,which combines the suppression of laser jitter and target tilt from the source and the improvement of spot positioning precision which represents the displacement measurement precision,and is experimentally verified.展开更多
基金National Natural Science Foundation of China under Grant Nos.10247005 and 70071047the Scientific Research Foundation of China University of Mining and Technology for the Young Teachers under Grant No.OK060119
文摘We study an intense beam propagating through the double periodic focusing channel by the particle-coremodel,and obtain the beam envelope equation.According to the Poincare-Lyapunov theorem,we analyze the stabilityof beam envelope equation and find the beam halo.The soliton control method for controlling the beam halo-chaos isput forward based on mechanism of halo formation and strategy of controlling beam halo-chaos,and we also prove thevalidity of the control method,and furthermore,the feasible experimental project is given.We perform multiparticlesimulation to control the halo by using the soliton controller.It is shown that our control method is effective.We alsofind the radial ion density changes when the ion beam is in the channel,not only the halo-chaos and its regeneration canbe eliminated by using the nonlinear control method,but also the density uniformity can be found at beam's centre aslong as an appropriate control method is chosen.
基金the Biomedical Science and Technology Support Special Project of Shanghai Science and Technology Committee(No.20S31908300)。
文摘Measurement precision of laser displacement sensor is subject to various factors,among which laser jitter and target tilt will directly lead to the position movement and shape variation of the laser spot,resulting in displacement measurement errors,so that researchers have to do a lot of research on the spot centering algorithm to weaken the above effects,which can treat the symptoms but not the root cause.Starting from the source of the problem,this paper proposes a double focus double peak solution,which uses a reflector to change the direction of the optical path,so that the imaging spots of the designed two optical paths focus on the same CMOS,forming a double peak structure.When laser jitter or target tilt occurs,the center of the two laser spots is shifted,but they move in the same direction,while their relative position remains unchanged.Therefore,the displacement can be characterized by the relative position of the two laser spots,so that laser jitter and target tilt are suppressed from the source.However,the two spots imaged on CMOS form a non-Gaussian distributed double peak structure,so the conventional laser spot centering algorithms are no longer applicable.To this end,a double peak adaptive threshold waveform extraction method combined with grayscale gravity method is proposed for spot centering algorithm,which combines the suppression of laser jitter and target tilt from the source and the improvement of spot positioning precision which represents the displacement measurement precision,and is experimentally verified.
