Accelerator Seminars
Co-Chairs: Anne-Marie Valente and Alex Bogacz
Members: Carlos Hernandez- Garcia, Joe Grames and Gwyn Williams
Accelerator Seminars will be scheduled weekly on
Thursdays from 11:00 a.m. - 12:00 p.m.
If you would like to schedule a seminar, please contact
Anne-Marie Valente or
Alex Bogacz for approval.
TITLE: Designing, Prototyping and Testing of Superconducting RF-Dipole Deflecting/Crabbing Cavities
SPEAKER: Subashini De Silva, Old Dominion University and Jefferson Lab
DATE: Thursday, May 2, 2013
TIME: 11:00 a.m.
LOCATION: CEBAF Center, Room L102
ABSTRACT: Deflecting/crabbing cavities serve a variety of purposes in different accelerator applications. Primarily in separating a single beam into multiple beams and in rotating bunches for head on collisions at the interaction point in particle colliders. Recently, new geometries for superconducting crabbing and deflecting cavities have been developed that have significantly improved properties over the standard TM110 type cavities. Compact superconducting deflecting/crabbing cavities are under development due to strict dimensional constraints and requirements in higher field gradients with low surface losses. Geometries that operate in TEM-like or TE-like modes support low operating frequencies, thus making the designs favorable for many of the deflecting/crabbing cavity applications. The superconducting rf-dipole design evolved from the parallel-bar design is such a geometry that has been considered for a number of deflecting and crabbing applications. Currently the rf-dipole cavity is under consideration as an rf separator for the Jefferson Lab 12 GeV upgrade and as a crabbing structure for a possible LHC luminosity upgrade. The detailed design analysis of the rf-dipole cavity will be presented with current developments on the fabrication and testing.
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TITLE: Preservation and Control of the Ion Polarization in the MEIC Rings
SPEAKER: Anatoliy Kondratenko, Science and Technique Laboratory "Zaryad"
DATE: Thursday, May 9, 2013
TIME: 11:00 a.m.
LOCATION: TED 2561
ABSTRACT: The main aspect of the spin motion in figure-8 accelerators is the absence of a preferred periodic spin precession axis. Such rings conceptually expand the capabilities of obtaining polarized high-energy beams in comparison to conventional colliders with Siberian snakes. The region of a zero spin tune is unique in figure-8 rings and allows for effective control of the beam polarization by special elements with small magnetic field integrals. We propose schemes to control the polarization of any ions (including deuterons) that allow one to adjust any polarization angle with respect to the beam direction in the experimental straight. We formulate the conditions for transparency of the orbital motion when integrating these inserts into the magnetic structure. We specify a response function for calculation of the “zero” harmonic of the spin perturbation. We investigate devices for compensation of the “zero” harmonic of the spin perturbation in a collider. We discuss possibilities for polarized beam experiments of an unprecedented precision level.
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