2011 Particle Accelerator Conference - List of Authors (Stancari, G.)

Paper

Title

Page

Results of Head-on Beam-beam Compensation Studies at the Tevatron

67

A. Valishev, G. Stancari
Fermilab, Batavia, USA

Funding: Work supported by the Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the United States Department of Energy, and by the DOE through the US LHC Accelerator Research Program (LARP).
At the Tevatron collider, we studied the feasibility of suppressing the antiproton head-on beam-beam tune spread using a magnetically confined 5-keV electron beam with Gaussian transverse profile overlapping with the circulating beam. When electron cooling of antiprotons is applied in regular Tevatron operations, the head-on beam-beam effect on antiprotons is small. Therefore, we first focused on the operational aspects, such as beam alignment and stability, and on fundamental observations of tune shifts, tune spreads, lifetimes, and emittances. We also attempted two special collider stores with only 3 proton bunches colliding with 3 antiproton bunches, to suppress long-range forces and enhance head-on effects. We present here the results of this study and a comparison between numerical simulations and observations, in view of the planned application of this compensation concept to RHIC.

Slides MOODN1 [2.680 MB]

MOP147

Experimental Study of Magnetically Confined Hollow Electron Beams in the Tevatron as Collimators for Intense High-Energy Hadron Beams

370

G. Stancari, G. Annala, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev
Fermilab, Batavia, USA

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP).
Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and tested at Fermilab for this purpose. It was installed in one of the Tevatron electron lenses in the summer of 2010. We present the results of the first tests of the hollow-beam collimation concept on individual 980-GeV antiproton bunches in the Tevatron.

Paper	Title	Page
MOODN1	Results of Head-on Beam-beam Compensation Studies at the Tevatron	67
	A. Valishev, G. Stancari Fermilab, Batavia, USA
	Funding: Work supported by the Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the United States Department of Energy, and by the DOE through the US LHC Accelerator Research Program (LARP). At the Tevatron collider, we studied the feasibility of suppressing the antiproton head-on beam-beam tune spread using a magnetically confined 5-keV electron beam with Gaussian transverse profile overlapping with the circulating beam. When electron cooling of antiprotons is applied in regular Tevatron operations, the head-on beam-beam effect on antiprotons is small. Therefore, we first focused on the operational aspects, such as beam alignment and stability, and on fundamental observations of tune shifts, tune spreads, lifetimes, and emittances. We also attempted two special collider stores with only 3 proton bunches colliding with 3 antiproton bunches, to suppress long-range forces and enhance head-on effects. We present here the results of this study and a comparison between numerical simulations and observations, in view of the planned application of this compensation concept to RHIC.
	Slides MOODN1 [2.680 MB]

MOP147	Experimental Study of Magnetically Confined Hollow Electron Beams in the Tevatron as Collimators for Intense High-Energy Hadron Beams	370
	G. Stancari, G. Annala, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev Fermilab, Batavia, USA
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP). Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and tested at Fermilab for this purpose. It was installed in one of the Tevatron electron lenses in the summer of 2010. We present the results of the first tests of the hollow-beam collimation concept on individual 980-GeV antiproton bunches in the Tevatron.