IPAC2011 - List of Authors (Derbenev, Y.S.)

Paper	Title	Page
WEPC047	Crab Crossing Schemes and Studies for Electron Ion Collider	2115
	S. Ahmed, S.U. De Silva, Y.S. Derbenev, G.A. Krafft, V.S. Morozov, B.C. Yunn, Y. Zhang JLAB, Newport News, Virginia, USA A. Castilla, J.R. Delayen ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Medium Energy Electron Ion Collider (MEIC) at JLab has been envisioned as future high energy particle accelerator beyond 12 GeV upgrade of CEBAF. Crab crossing of colliding electron and ion beams is essential for accommodating high bunch repetition frequency in the conceptual design of MEIC. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. This requires the separation of two beams quickly to avoid parasitic collisions and the minimization of synchrotron-betatron resonance near IP which can be fulfilled by employing the crab crossing concept first proposed by R. Palmer. Let us call this original scheme as transverse crabbing for the sake of comparison with dispersive crabbing which employs the existing accelerating/bunching RF cavities and dispersion function in the section where the cavity is installed as originally proposed by G. Jackson. In this paper, we report the beam transport and optics for both transverse and dispersive crabbing schemes followed by basic beam dynamics. Moreover, alignment and stability calculations together with synchro-betatron beam dynamics will be discussed.

WEPZ009	Parametric-Resonance Ionization Cooling in Twin-Helix	2784
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA A. Afanasev, R.P. Johnson Muons, Inc, Batavia, USA B. Erdelyi, J.A. Maloney Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by DOE SBIR grant DE-SC0005589. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

THPZ017	Achromatic Low-beta Interaction Region Design for an Electron-ion Collider	3723
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by Muons, Inc. An achromatic Interaction Region (IR) design concept is presented with an emphasis on its application at an electron-ion collider. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB’s placed symmetrically around an interaction point (IP) allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. Special attention is paid to the difference in the electron and ion IR design requirements. We discuss geometric matching of the electron and ion IR footprints. We investigate limitations on the momentum acceptance in this IR design.

Paper

Title

Page

Crab Crossing Schemes and Studies for Electron Ion Collider

2115

S. Ahmed, S.U. De Silva, Y.S. Derbenev, G.A. Krafft, V.S. Morozov, B.C. Yunn, Y. Zhang
JLAB, Newport News, Virginia, USA
A. Castilla, J.R. Delayen
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Medium Energy Electron Ion Collider (MEIC) at JLab has been envisioned as future high energy particle accelerator beyond 12 GeV upgrade of CEBAF. Crab crossing of colliding electron and ion beams is essential for accommodating high bunch repetition frequency in the conceptual design of MEIC. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. This requires the separation of two beams quickly to avoid parasitic collisions and the minimization of synchrotron-betatron resonance near IP which can be fulfilled by employing the crab crossing concept first proposed by R. Palmer. Let us call this original scheme as transverse crabbing for the sake of comparison with dispersive crabbing which employs the existing accelerating/bunching RF cavities and dispersion function in the section where the cavity is installed as originally proposed by G. Jackson. In this paper, we report the beam transport and optics for both transverse and dispersive crabbing schemes followed by basic beam dynamics. Moreover, alignment and stability calculations together with synchro-betatron beam dynamics will be discussed.

WEPZ009

Parametric-Resonance Ionization Cooling in Twin-Helix

2784

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev, R.P. Johnson
Muons, Inc, Batavia, USA
B. Erdelyi, J.A. Maloney
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by DOE SBIR grant DE-SC0005589. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

THPZ017

Achromatic Low-beta Interaction Region Design for an Electron-ion Collider

3723

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by Muons, Inc.
An achromatic Interaction Region (IR) design concept is presented with an emphasis on its application at an electron-ion collider. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB’s placed symmetrically around an interaction point (IP) allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. Special attention is paid to the difference in the electron and ion IR design requirements. We discuss geometric matching of the electron and ion IR footprints. We investigate limitations on the momentum acceptance in this IR design.