During the PEP-II LER commissioning run in July 1998 the beam pro le in the tune up dump pro le monitor just before LER injection showed an anomalous parbolic shape. The sextupole component of the eld of bend magnets B2 and B4 in the beginning of the south injection tunnel (SIT) was thought to be the cause of this. An o -line model of the B2/B4 bend magnet eld was created using DIMAD. Results o...

HISPEC (High-resolution in-flight spectroscopy) deals with a versatile, high resolution, high efficiency spectroscopy set-up to address questions in nuclear structure, reactions and astrophysics using radioactive beams from the Super FRS with energies of 3-150 MeV/u. The radioactive beams will be used for γ-ray, charged particle and neutron spectroscopy. The HISPEC set-up will comprise beam tra...

Artificial collisions during particle tracking with selfconsistent space charge lead to diffusion-like, numerical effects. The artificial collisions generate a stochastic noise spectrum. As a consequence the entropy and the emittance can grow along periodic focusing structures. The growth rates depend on the number of simulation macro-particles and on the space charge tune shifts. For long-term...

Traditional beam tracking has severe performance loss under the high mobility and narrow scenario. To alleviate degradation, we propose an adaptive beamwidth control for millimeter wave tracking. Using particle filter, perform tracking, i.e., which is to estimate channel gain angle-of-arrival (AoA). Based on updated standard deviation of AoA, adequate set via partial activation antenna array. S...

We developed a new method for real-time, three-dimensional tracking of fluorescent particles. The instrument is based on a laser-scanning confocal microscope where the focus of the laser beam is scanned or orbited around the particle. Two confocal pinholes are used to simultaneously monitor regions immediately above and below the particle and a feedback loop is used to keep the orbit centered o...

We examine the use of sextupole magnets to correct nonlinearities in the longitudinal phase space transformation of a relativistic beam of charged particles in a dispersionless translating section, or dogleg. Through heuristic analytical arguments and examples derived from recent experimental endeavors, and augmented by simulations using the particle tracking codes PARMELA and ELEGANT, sextupol...

1098-4402= We examine the use of sextupole magnets to correct nonlinearities in the longitudinal phase space transformation of a relativistic beam of charged particles in a dispersionless translating section, or dogleg. Through heuristic analytical arguments and examples derived from recent experimental efforts, augmented by simulations using the particle tracking codes PARMELA and ELEGANT, sex...

The 3D finite-element gun and collector modeling code, MICHELLE, has been under development at SAIC in collaboration with industrial partners and national laboratories (ref. 1). This development program has been designed to address the shortcomings of current beam optics simulation and modeling tools for vacuum electron devices. The program specifically targets problem classes including gridded...

We demonstrate a miniaturized single beam fiber optical trapping probe based on a high numerical aperture graded index (GRIN) micro-objective lens. This enables optical trapping at a distance of 200μm from the probe tip. The fiber trapping probe is characterized experimentally using power spectral density analysis and an original approach based on principal component analysis for accurate parti...

we derive error estimates in the appropriate norms, for the streamlinediffusion (sd) finite element methods for steady state, energy dependent,fermi equation in three space dimensions. these estimates yield optimal convergencerates due to the maximal available regularity of the exact solution.high order sd method together with implicit integration are used. the formulationis strongly consistent...