M. Blaskiewicz

Commissioning of RHIC deuteron-gold collisions

Deuteron and gold beams have been accelerated to a collision energy of /spl radic/s = 200 GeV/u in the Relativistic Heavy Ion Collider (RHIC), providing the first asymmetric-species collisions of this complex. Necessary changes for this mode of operation include new ramping software and asymmetric crossing angle geometries. This paper reviews machine performance, problems encountered and their solutions, and accomplishments during the 16 weeks of ramp-up and operations.

Transverse instabilities in RHIC

The beam quality in RHIC can be significantly impacted by a transverse instability which can occur just after transition. Data characterizing the instability are presented and analyzed. Techniques for ameliorating the situation are considered.

Longitudinal solitons in RHIC

Stable, coherent, longitudinal oscillations have been observed in the RHIC accelerator. Within the context of perturbation theory, the beam parameters and machine impedance suggest these oscillations should be Landau damped. When nonlinear effects are included, long lived, stable oscillations become possible for low intensity beams. Simulations and theory are compared with data.

Coupling impedance measurements of the SNS RF cavity and extraction kicker magnet

The Spallation Neutron Source (SNS) is a high intensity machine with peak currents in the accumulator ring reaching /spl sim/50 A at the 1.4 MW design level. This unprecedented beam intensity necessitates a careful investigation of coupling impedances posing as potential performance limitations. Impedance estimates of accelerator components pointed to the RF cavities and extraction kickers as the major contributors to the impedance budget and extensive measurements were performed on their prototypes. Impedance measurements were performed using the standard wire method.

FFAG lattice for muon acceleration with distributed RF

A future muon collider or neutrino factory requires fast acceleration to minimize muon decay. We have previously described an FFAG ring that accelerated muons from 10 to 20 GeV in energy. The ring achieved its large momentum acceptance using a low-emittance lattice with a small dispersion. In this paper, we present an update on that ring. We have used design tools that more accurately represent the rings behavior at large momentum offsets. We have also improved the dynamic aperture from the earlier design.

Commissioning results and applications

Abstract This section describes both: successful commissioning of RHIC and the state of the art RHIC accelerator physics tools/applications. The commissioning provided collisions of the fully stripped gold ions at a beam energy of 65 GeV/nucleon in all four experiments “STAR”, “PHENIX”, “PHOBOS”, and “BRAHMS”. They collected more than 3 μb −1 of data. Measurements of betatron and dispersion functions have shown excellent agreement with predictions. Diagnostic results from tune-meter, wall current monitor, chromaticity, decoupling measurements, ionization beam profile monitor, Schottky monitors, etc. are shown. Progress towards stable gold ion beam stores with optimized luminosity is described [Proceedings of the HEACC2001 The 18th International Conference On High Energy Accelerators, March 26–30, 2001, Tsukuba, Japan, March, 2001]. Few major commissioning challenges are described first. The most important results, from some of the RHIC systems, are shown in the next section. In the following section bringing beams from two separate “blue” and “yellow” rings into collisions and measurements during long beam stores are described. In the summary part necessary steps and commissioning of additional systems during the next RHIC-2001 run are mentioned.