IPAC2011 - List of Authors (Kurennoy, S.S.)

Paper	Title	Page
MOPZ029	Aperture Windows in High-Gradient Cavities for Accelerating Low-Energy Muons	862
	S.S. Kurennoy, A.J. Jason, W.M. Tuzel LANL, Los Alamos, New Mexico, USA
	A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications. The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings muons to a kinetic energy of about 200 MeV over a distance of the order of 10 m. At this energy, both ionization cooling of the muon beam and its further acceleration become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM010) RF cavities with wide beam apertures closed by thin conducting windows. The high gradients lead to significant heat deposition on the aperture windows. Here we explore options for the edge-cooled thin windows in the zero-mode cavities. Electromagnetic and thermal-stress computations are complemented by thermal-test experiments to select the best solution for the aperture windows. S.S. Kurennoy, A.J. Jason, H. Miyadera, “Large-Acceptance Linac for Accelerating Low-Energy Muons,” Proc. of IPAC10, p. 3518 (2010).

WEPS067	An H-Mode Accelerator with PMQ Focusing as a LANSCE DTL Replacement	2655
	S.S. Kurennoy, L. Rybarcyk, T.P. Wangler LANL, Los Alamos, New Mexico, USA
	High-efficiency normal-conducting RF accelerating structures based on H-mode cavities with a transverse beam focusing by permanent-magnet quadrupoles (PMQ) have been developed for beam velocities in the range of a few percent of the speed of light. At these low beam velocities, an inter-digital H-mode (IH-PMQ) linac is an order of magnitude more efficient than a standard drift-tube linac (DTL). At the Los Alamos Neutron Science Center (LANSCE), upgrades of the proton linac front end are currently under consideration. In view of these plans, we explore a further option of replacing the aging LANSCE DTL by an efficient H-PMQ accelerator. Here we assume that a 201.25-MHz RFQ-based front end up to 750 keV (4% of the speed of light) is followed first by IH-PMQ structures and then by cross-bar H-mode cavities with PMQ focusing (CH-PMQ). Such an H-PMQ linac would bring proton and H⁻ beams to the energy of 100 MeV and transfer them into the existing side-coupled-cavity linac (CCL). Results of the combined electromagnetic and beam-dynamics modeling of the proposed H-PMQ accelerator will be presented. S.S. Kurennoy et al., “H-Mode Accelerating Structures with PMQ Beam Focusing,” PRST-AB, 2011 (submitted).

WEPS068	Progress towards an RFQ-based Front End for LANSCE	2658
	R.W. Garnett, S.S. Kurennoy, J.F. O'Hara, L. Rybarcyk LANL, Los Alamos, New Mexico, USA A. Schempp IAP, Frankfurt am Main, Germany
	Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396. The LANSCE linear accelerator at Los Alamos National Laboratory provides H⁻ and H⁺ beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. These beams are initially accelerated to 750 keV using Cockcroft-Walton (CW) based injectors that have been in operation for over 37 years. They have failure modes which can result in prolonged operational downtime due to the unavailability of replacement parts. To reduce long-term operational risks and to realize future beam performance goals in support of the Materials Test Station (MTS) and the Matter-Radiation Interactions in Extremes (MaRIE) Facility, plans are underway to develop a Radio-Frequency Quadrupole (RFQ) based front end as a modern injector replacement for the existing CW injectors. Our progress to date will be discussed.

Paper

Title

Page

Aperture Windows in High-Gradient Cavities for Accelerating Low-Energy Muons

862

S.S. Kurennoy, A.J. Jason, W.M. Tuzel
LANL, Los Alamos, New Mexico, USA

A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications*. The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings muons to a kinetic energy of about 200 MeV over a distance of the order of 10 m. At this energy, both ionization cooling of the muon beam and its further acceleration become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM010) RF cavities with wide beam apertures closed by thin conducting windows. The high gradients lead to significant heat deposition on the aperture windows. Here we explore options for the edge-cooled thin windows in the zero-mode cavities. Electromagnetic and thermal-stress computations are complemented by thermal-test experiments to select the best solution for the aperture windows.
* S.S. Kurennoy, A.J. Jason, H. Miyadera, “Large-Acceptance Linac for Accelerating Low-Energy Muons,” Proc. of IPAC10, p. 3518 (2010).

WEPS067

An H-Mode Accelerator with PMQ Focusing as a LANSCE DTL Replacement

2655

S.S. Kurennoy, L. Rybarcyk, T.P. Wangler
LANL, Los Alamos, New Mexico, USA

High-efficiency normal-conducting RF accelerating structures based on H-mode cavities with a transverse beam focusing by permanent-magnet quadrupoles (PMQ) have been developed for beam velocities in the range of a few percent of the speed of light*. At these low beam velocities, an inter-digital H-mode (IH-PMQ) linac is an order of magnitude more efficient than a standard drift-tube linac (DTL). At the Los Alamos Neutron Science Center (LANSCE), upgrades of the proton linac front end are currently under consideration. In view of these plans, we explore a further option of replacing the aging LANSCE DTL by an efficient H-PMQ accelerator. Here we assume that a 201.25-MHz RFQ-based front end up to 750 keV (4% of the speed of light) is followed first by IH-PMQ structures and then by cross-bar H-mode cavities with PMQ focusing (CH-PMQ). Such an H-PMQ linac would bring proton and H⁻ beams to the energy of 100 MeV and transfer them into the existing side-coupled-cavity linac (CCL). Results of the combined electromagnetic and beam-dynamics modeling of the proposed H-PMQ accelerator will be presented.
* S.S. Kurennoy et al., “H-Mode Accelerating Structures with PMQ Beam Focusing,” PRST-AB, 2011 (submitted).

WEPS068

Progress towards an RFQ-based Front End for LANSCE

2658

R.W. Garnett, S.S. Kurennoy, J.F. O'Hara, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA
A. Schempp
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The LANSCE linear accelerator at Los Alamos National Laboratory provides H⁻ and H⁺ beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. These beams are initially accelerated to 750 keV using Cockcroft-Walton (CW) based injectors that have been in operation for over 37 years. They have failure modes which can result in prolonged operational downtime due to the unavailability of replacement parts. To reduce long-term operational risks and to realize future beam performance goals in support of the Materials Test Station (MTS) and the Matter-Radiation Interactions in Extremes (MaRIE) Facility, plans are underway to develop a Radio-Frequency Quadrupole (RFQ) based front end as a modern injector replacement for the existing CW injectors. Our progress to date will be discussed.