An electron beam probe（EBP） is a detector which makes use of a low-intensity and low-energy electron beam to measure the transverse profile, bunch shape, beam neutralization and beam wake field of an intense beam wi...An electron beam probe（EBP） is a detector which makes use of a low-intensity and low-energy electron beam to measure the transverse profile, bunch shape, beam neutralization and beam wake field of an intense beam with small dimensions. While it can be applied to many aspects, we limit our analysis to beam distribution reconstruction.This kind of detector is almost non-interceptive for all of the beam and does not disturb the machine environment.In this paper, we present the theoretical aspects behind this technique for beam distribution measurement and some simulation results of the detector involved. First, a method to obtain a parallel electron beam is introduced and a simulation code is developed. An EBP as a profile monitor for dense beams is then simulated using the fast scan method for various target beam profiles, including KV distribution, waterbag distribution, parabolic distribution,Gaussian distribution and halo distribution. Profile reconstruction from the deflected electron beam trajectory is implemented and compared with the actual profile, and the expected agreement is achieved. Furthermore, as well as fast scan, a slow scan, i.e. step-by-step scan, is considered, which lowers the requirement for hardware, i.e. Radio Frequency deflector. We calculate the three-dimensional electric field of a Gaussian distribution and simulate the electron motion in this field. In addition, a fast scan along the target beam direction and slow scan across the beam are also presented, and can provide a measurement of longitudinal distribution as well as transverse profile simultaneously. As an example, simulation results for the China Accelerator Driven Sub-critical System（CADS） and High Intensity Heavy Ion Accelerator Facility（HIAF） are given. Finally, a potential system design for an EBP is described.展开更多
Canceling grids accommodating probes in comparative molecular field analysis(CoMFA),the idea of flexibleness is introduced into the CoMFA,and in combination with swarm intelligent algorithm which attempts to optimize ...Canceling grids accommodating probes in comparative molecular field analysis(CoMFA),the idea of flexibleness is introduced into the CoMFA,and in combination with swarm intelligent algorithm which attempts to optimize distributions of diverse probes around drug molecules,a new 3D-QSAR method is proposed in this context as flexible comparative molecular field analysis(FCoMFA).In preliminary at-tempts to performing QSAR studies on 47 glycogen phosphorylase inhibitors,FCoMFA is employed and confirmed to be potent to exploring ligand-receptor interaction manners at active positions and thus to generating stable and predictable models.Simultaneously by an intuitive graphics regarding probe distribution patterns,impacts of different substituted groups on activities is also given an insight into.展开更多
文摘An electron beam probe（EBP） is a detector which makes use of a low-intensity and low-energy electron beam to measure the transverse profile, bunch shape, beam neutralization and beam wake field of an intense beam with small dimensions. While it can be applied to many aspects, we limit our analysis to beam distribution reconstruction.This kind of detector is almost non-interceptive for all of the beam and does not disturb the machine environment.In this paper, we present the theoretical aspects behind this technique for beam distribution measurement and some simulation results of the detector involved. First, a method to obtain a parallel electron beam is introduced and a simulation code is developed. An EBP as a profile monitor for dense beams is then simulated using the fast scan method for various target beam profiles, including KV distribution, waterbag distribution, parabolic distribution,Gaussian distribution and halo distribution. Profile reconstruction from the deflected electron beam trajectory is implemented and compared with the actual profile, and the expected agreement is achieved. Furthermore, as well as fast scan, a slow scan, i.e. step-by-step scan, is considered, which lowers the requirement for hardware, i.e. Radio Frequency deflector. We calculate the three-dimensional electric field of a Gaussian distribution and simulate the electron motion in this field. In addition, a fast scan along the target beam direction and slow scan across the beam are also presented, and can provide a measurement of longitudinal distribution as well as transverse profile simultaneously. As an example, simulation results for the China Accelerator Driven Sub-critical System（CADS） and High Intensity Heavy Ion Accelerator Facility（HIAF） are given. Finally, a potential system design for an EBP is described.
基金Supported by National High Technology(863)Program(Grant No.2006AA02Z312)the State Key Laboratory of Chemo/Biosensing and Chemometrics Foundation(Grant No.0501201)Chongqing University Innovation Fund(Grant No.030506)
文摘Canceling grids accommodating probes in comparative molecular field analysis(CoMFA),the idea of flexibleness is introduced into the CoMFA,and in combination with swarm intelligent algorithm which attempts to optimize distributions of diverse probes around drug molecules,a new 3D-QSAR method is proposed in this context as flexible comparative molecular field analysis(FCoMFA).In preliminary at-tempts to performing QSAR studies on 47 glycogen phosphorylase inhibitors,FCoMFA is employed and confirmed to be potent to exploring ligand-receptor interaction manners at active positions and thus to generating stable and predictable models.Simultaneously by an intuitive graphics regarding probe distribution patterns,impacts of different substituted groups on activities is also given an insight into.
