A hybrid fast-multipole technique for space-charge tracking with halos
The simulation of injection and accumulation of intense proton beams in synchrotrons and accumulator rings requires a flexible and robust treatment of space-charge effects. In particular, the simulation must be able to correctly incorporate the large-amplitude beam halo which is known to arise from a variety of mechanisms. This paper describes a technique for the efficient and accurate evaluation of transverse space-charge forces in a simulated beam that may include halo particles at arbitrarily large amplitudes. The technique uses the Fast Multipole Method (FMM), together with some elements of Particle-In-Cell (PIC) methods, to evaluate the space-charge field at the location of each macroparticle. Timing comparisons show that when a large-amplitude halo is present this hybrid technique is significantly faster than plain FMM and also offers performance advantages over PIC/FFT field calculations with equivalent spatial resolution. The hybrid FMM method has been implemented and tested in the multiparticle tracking and simulation code ACCSIM and some initial results are presented.
An approach to the design of space-charge limited high intensity synchrotrons
A design procedure for storage rings has been reported previously . The approach proposed here concerns m a i n l y s y n c h r o t r o n s which a c c e l e r a t e i n t e n s e beams of p r o t o n s o r h e a v i e r i o n s ; i t c o u l d a l s o be u s e f u l f o r t h e d e s i g n of c o m p r e s s o r o r s t r e t c h e r r i n g s o r s i m i l a r f a c i l i t i e s . The a p p r o a c h i s b a s e d on e x p e r i e n c e g a i n e d in t h e i n v o l v e m e n t w i t h h a l f a dozen m a c h i n e s and i n t h e d e s i g n and d e v e l o p m e n t of t h e CPS B o o s t e r , which by now a c c e l e r a t e s in one r i n g (vacuum chamber a p e r t u r e s 132 x 63 mm) 8 x 10 ppp w i t h 50 MeV i n j e c t i o n .
Degradable polymers : principles and applications
1. Why Biodegradable Polymers? G. Scott. 2. An Overview of Biodegradable Polymers and Biodegradation of Polymers S.H. Huang. 3. Degradation and Stabilization of Carbon-Chain Polymers G. Scott. 4. Techniques and Methods of Polymer Degradation S. Karlsson, A.-C. Albertsson. 5. Biodegradation of Aliphatic Polyesters Suming Li, M. Vert. 6. Starch-Polymer Composites C. Bastioli. 7. Polymers from Renewable Sources E. Chiellini, et al. 8. Sustainable Poly(Hydroxyalkanoate) (PHA) Production G. Braunegg. 9. Polyhydroxyalkanoates: Properties and Modification for High Volume Application I. Chodak. 10. Biodegradable Polymers in Medicine E Piskin. 11. Environmentally Biodegradable Water-Soluble Polymers G. Swift. 12. Plastics and the Environment J. Guillet. 13. Degradable Hydrocarbon Polymers in Waste and Litter Control G. Scott, D.M. Wiles. Subject Index.