Transverse Instabilities in the Fermilab Recycler

Abstract

Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots.In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly lowered for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

“…For example, filament lifetime data, the key sustainability issue for the TRIUMF DC H¯/D¯ source utilized in commercial and research environments is sparse. The authors of this paper are thankful for contributors [21][22][23][24][25][26][27] for the table in Fig. 5 containing lifetime data for the following filament configurations: (a) 1 Tungsten arch-shaped filament segment (φ = 2.4 mm), (b) 2 semi-circular Tantalum filament segments (φ = 2 mm), (c) 4 semi-circular Tantalum filament segments (φ = 1.6 mm), and (d) 1 pigtail Tungsten alloy filament segment (φ = 3 mm) [20].…”

Pbar Beam Stacking in the Recycler by Longitudinal Phase-space Coating

“…Significant theoretical as well as experimental research took place during the past two decades particularly due to its use in the Recycler Ring [9][10][11][12][13][14], induction accelerator at KEK [15], R&D effort at CERN and BNL [16] and the foreseen NESR facility at GSI [17]. The Recycler Ring at Fermilab is an 8 GeV proton/antiproton permanent magnet storage ring.…”