HB2014 - Table of Session: WEO3AB (Working Group AF / D)

Paper

Title

Page

Measurements of Beam Halo Diffusion and Population Density in the Tevatron and in the Large Hadron Collider

294

G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US DOE. Work partially supported by US LARP and by EU FP7 HiLumi LHC, Grant Agreement 284404.
Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of transverse damper excitations. New proposals for nondestructive halo population density measurements are also briefly discussed.

Slides WEO3AB01 [7.131 MB]

WEO3AB02

Status of Preparations for a 10 us H⁻ Laser-Assisted Stripping Experiment

299

S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A. Rakhman, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
F.G. Garcia, N.F. Luttrell
UTK, Knoxville, Tennessee, USA
Y. Takeda
KEK, Ibaraki, Japan

At the Spallation Neutron Source accelerator preparations are underway for a 10 us laser-assisted H⁻ stripping experiment. This is a three orders of magnitude increase in pulse duration compared the to initial 2006 proof of principle experiment. The focus of the experiment is the validation of methods that reduce the average laser power requirement, including laser-ion beam temporal matching, ion beam dispersion tailoring, and specialized longitudinal and transverse optics. In this presentation we report on the status of preparations and the anticipated schedule for the experiment.

Slides WEO3AB02 [7.250 MB]

WEO3AB03

The Design and Construction Status of Injection and Extraction System for CSNS/RCS

S. Wang
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) accelerator consists of an 80MeV H⁻ linac and a 1.6GeV proton Rapid Cycling Synchrotron(RCS), and it provides 100 kW beam to neutron target. The injection and extraction systems play an important role in the RCS. The H⁻ stripping painting and single turn extraction are adopted in the RCS. Now the hardware of the injection and extraction systems are being fabricated and tested. The design of the injection system and extraction system of the RCS are introduced, including some simulation study and optimization. The construction status of hardware is also described, including the test results of hardware of the injection and extraction systems.

Slides WEO3AB03 [5.085 MB]

Paper	Title	Page
WEO3AB01	Measurements of Beam Halo Diffusion and Population Density in the Tevatron and in the Large Hadron Collider	294
	G. Stancari Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US DOE. Work partially supported by US LARP and by EU FP7 HiLumi LHC, Grant Agreement 284404. Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of transverse damper excitations. New proposals for nondestructive halo population density measurements are also briefly discussed.
	Slides WEO3AB01 [7.131 MB]

WEO3AB02	Status of Preparations for a 10 us H⁻ Laser-Assisted Stripping Experiment	299
	S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A. Rakhman, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA F.G. Garcia, N.F. Luttrell UTK, Knoxville, Tennessee, USA Y. Takeda KEK, Ibaraki, Japan
	At the Spallation Neutron Source accelerator preparations are underway for a 10 us laser-assisted H⁻ stripping experiment. This is a three orders of magnitude increase in pulse duration compared the to initial 2006 proof of principle experiment. The focus of the experiment is the validation of methods that reduce the average laser power requirement, including laser-ion beam temporal matching, ion beam dispersion tailoring, and specialized longitudinal and transverse optics. In this presentation we report on the status of preparations and the anticipated schedule for the experiment.
	Slides WEO3AB02 [7.250 MB]

WEO3AB03	The Design and Construction Status of Injection and Extraction System for CSNS/RCS
	S. Wang IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) accelerator consists of an 80MeV H⁻ linac and a 1.6GeV proton Rapid Cycling Synchrotron(RCS), and it provides 100 kW beam to neutron target. The injection and extraction systems play an important role in the RCS. The H⁻ stripping painting and single turn extraction are adopted in the RCS. Now the hardware of the injection and extraction systems are being fabricated and tested. The design of the injection system and extraction system of the RCS are introduced, including some simulation study and optimization. The construction status of hardware is also described, including the test results of hardware of the injection and extraction systems.
	Slides WEO3AB03 [5.085 MB]