Magnetic Field and Beam Dynamics Calculations for SUSE
The SuSe magnet system is designed using the program GFUN3D. A small version of this program was connected to a general fit program by means of which the current in the main and trim coils was determined for a given isochronous mean field B¿(r). For beam dynamics calculations with the code GOC accurate fields (¿B¿/B¿ ¿ 1%) were used which were obtained by means of the program GFUN400 where the unique part of the magnet iron is subdivided into 400 elements at maximum. Several coil systems have been investigated. In an alternative design all coils have straigth sections which are easier to manufacture than coils with negative curvature. The main coils have a largest radial extension of 3.08 m. There are 22 correcting coils inside each main coil.
Magnetic field optimization and beam dynamics calculations for SuSe
The superconducting sector magnets of SuSe have been designed using the newly developed program GFUNFIT. By means of this program the deviation of the desired magnetic field from the actual value, which is produced by the magnetic system, can be minimized to within 0.5 Gauss by variation of several parameters, such as conductor current, geometry of conductors and of iron. Varying these parameters, fields with an absolute accuracy of ΔB/B ≲ 1 % have been obtained using the finite-element programs GFUN3D and GETM400. The code GOC has been used to study the beam dynamics in these fields. Two examples for fully stripped heavy ions (q/A = 0.5) with maximum and half maximum final energies (T2/A = 300 MeV/n and 150 MeV/n) are given.
Improvement of RHIC warm beam vacuum for high intensity operation
With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at a few warm vacuum sections. Improvement of the warm sections has been carried out in last year's shutdown. Extensive in-situ bakes, additional UHV pumping, electron detectors and beam tube solenoids have been implemented. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. The effectiveness of these measures in reducing the beam induced pressure bumps and in increasing the vacuum system reliability are discussed and summarized.