摘要:

The discussion we had on ‘‘maps’’ in this workshop was, as usual, punctuated with misleading contents. First of all, the word ‘‘map’’ was used improperly. A tracking code for example is a map! Given a location ‘‘s’’ in the ring, it ‘‘maps’’ the initial phase space vectorzS=(xs, x’s, ...) to its final vlaue at s’,zs.

ISSN:0094-243X    

DOI:10.1063/1.42323

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A brief outline of the longitudinal single particle dynamics at transition is presented in terms of phase‐space mappings. Simple qunatitative prediction about the phase‐space dilution is made. More realistic simulation (ESME) of the transition crossing is carried out (including various collective and single particle effects contributing to the longitudinal emittance blow up). The simulation takes into account the longitudinal space‐charge force (bunch length oscillation), the transverse space‐charge (the Umsta¨tter effect) and finally the dispersion of the momentum compaction factor (the Johnsen effect). As a result of this simulation one can separate relative strengths of the above mechanisms and study their individual effects on the longitudinal phase‐space evolution, espcially filamentation of the bunch and formation of a ‘‘galaxy‐like’’ pattern.

ISSN:0094-243X    

DOI:10.1063/1.42324

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Fermilab has undertaken a series of upgrades to the TEVATRON to increase the luminosity of the collider. During the 1988–1989 collider run, the peak luminosity was limited to approximately 1.6×1030cm−2sec−1. This limit was set by the head‐on beam‐beam tuneshift of 0.025. Increasing the luminosity requires decreasing the tuneshift. The principle upgrade in the TEVATRON is the installation of electrostatic separators to separate the beams both horizontally and vertically at all crossings expect the experimental interactions regions. Introduction of separators has substantial implications for beam dynamics in the TEVATRON, and I will describe some of the accelerator physics issues which must be solved.

ISSN:0094-243X    

DOI:10.1063/1.42285

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

This paper is a review of collective effects in Fermilab accelerators which are currently being studied. The discussion will start at the low energy side of the injector chain and progress toward the Tevatron.

ISSN:0094-243X    

DOI:10.1063/1.42286

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The acceleration and transport of beams with high currents and low emittances are very carefully controlled for the SLC Linacl. Both longitudinal and transverse wakefields affect strongly the trajectory and emittance corrections used for operations during collisions. Longitudinal beam loading introduces an internal energy spread. This loading produces the expected doubled peaked energy spectra while reducing the overall available energy for acceleration. Transverse wakefields cause rapid oscillation amplitude growth with injection errors but can be ameliorated with transverse wakefield (BNS) damping. Transverse wakefields cause an apparent change in the lattice strength, affecting the interpretation of lattice diagnostics. Oscillations also produce non‐gaussian transverse density distributions, which must be controlled for emittance and background reduction. Finally, the small misalignments of the accelerating structure enlarge the emittance of the beam. They can be controlled through off‐axis trajectories and through systematic waveguide movements.

ISSN:0094-243X    

DOI:10.1063/1.42287

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A technique is described for reconstructing the first order transport matrix (R) for a given beam line. Emphasis is placed on the rigorous error analysis of the data, and the use of powerful statistical techniques to estimate unknown systematic errors. The application of the technique to the measurement and subsequent correction of the SLC Arcs is briefly described.

ISSN:0094-243X    

DOI:10.1063/1.42288

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

This year’s dynamic aperture experiments at the SPS concentrated on the study of the diffusion enhancement by tune modulation in presence of strong nonlinear fields. The aim of this experiment is to specify an upper limit for the power supply ripple in view of the LHC, the proposed hadron collider in the LEP tunnel. Due to strong, unavoidable non‐linearities of the superconducting magnets we expect this accelerator to be very sensitive to power supply ripple. An additional tune modulation, large in comparison with the natural one, was therefore introduced in the SPS and a particle diffusion was meaured for several modulation amplitudes. The combined effect of two frequencies with equal ampltiude was also tested. In parallel long‐term tracking studies have been performed, which allow to find the dynamic aperture for a model of the SPS with the added non‐linearities and tune modulations.

ISSN:0094-243X    

DOI:10.1063/1.42289

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The nonlinear beam dynamics of transverse betatron oscillations were studied experimentally at the IUCF Cooler Ring. Particles were kicked onto resonance islands and the properties of these islands were studied. The island tune was determined with high precision by Fourier analyzing the spectrum containing the islands and the properties of these island were studied. The island tune was determined with high precision by Fourier analyzing the spectrum containing the island oscillations. The island width was estimated based on a single resonance model. The Hamiltonian of particle motion near a resonance condition was thus deduced.

ISSN:0094-243X    

DOI:10.1063/1.42291

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

This report gives a summary of the discussions in the Working Group on Errors during the Fifth Advanced ICFA Beam Dynamics Workshop, held at Corpus Christi, TX, USA from 3 to 8 October 1991. The following sources of errors in circular and linear accelerators and storage rings were discussed: Linear coupling, static position errors, dynamic position errors, nonlinear multipole components, persistent currents in superconducting magnets, and power supply ripple. The findings of the working group are summarized in the conclusions.

ISSN:0094-243X    

DOI:10.1063/1.42292

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.42293

出版商:AIP    

年代:1992

数据来源: AIP