SRF2011 - List of Authors (Grassellino, A.)

Paper

Title

Page

Performance Limitation Studies on ISAC-II QWR’s and e-Linac Elliptical Cavities at TRIUMF

97

D. Longuevergne, A. Grassellino, P. Kolb, R.E. Laxdal, V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

TRIUMF has been operating successfully for several years numerous 100MHz class superconducting quarter wave resonators on the ISAC-II heavy ion linac and is now developing a 1.3 GHz activity to build the e-linac, a 50 MeV superconducting electron linac to produce radioisotopes by photofission. Several studies on cavity treatments are ongoing to both enhance ISAC-II QWR performances and to meet the requirements on the e-linac elliptical cavities. This paper will summarize the main development efforts to understand performance limitations in these cavities.

Poster MOPO017 [0.689 MB]

MOPO020

Nine-cell Elliptical Cavity Development at TRIUMF

107

V. Zvyagintsev, C.D. Beard, A. Grassellino, D. Kaltchev, P. Kolb, R.E. Laxdal, D. Longuevergne, B.S. Waraich
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
M. Ahammed
DAE/VECC, Calcutta, India
R.O. Bolgov, N.P. Sobenin
MEPhI, Moscow, Russia
R. Edinger
PAVAC, Richmond, B.C., Canada

The superconducting e-Linac project at TRIUMF requires a new nine cell elliptical cavity at 1.3GHz of TESLA influenced design capable of providing a CW accelerating voltage of 10MV at 10mA of beam intensity. This corresponds to a challenging 100kW of beam loaded rf power and a Beam Break-up (BBU)threshold in multi-pass mode of Rd/Q*QL=10MOhms. For this purpose we use two opposed CPI 60kW cw rated couplers. Another challenge is to provide HOM damping for the possibility of multi-pass ERL operation by means of end cell optimization and higher order mode (HOM) dampers. Results of the cavity design work including developments toward a passive HOM damper will be discussed.

TUIOB04

Muon Spin Rotation/Relaxation Studies of Niobium for SRF applications

330

A. Grassellino
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

One of the outstanding scientific issues related to superconducting radio frequency cavities made of high-purity bulk niobium is the occurrence of field dependent losses in the walls of the niobium cavity. These losses occur at different RF field levels and pose severe limitations to the niobium technology for both CW or pulsed applications. In this presentation I will explain the results of an experiment which focused on understanding the mechanisms behind losses in the high field regime (above 80-100mT peak magnetic fields). The problem was studied utilizing the unique TRIUMF muon spin rotation (muSR) facility to investigate superconducting properties of niobium samples. In particular, the muon spin rotation experiments aimed at studying the field of first flux entry in high field Q-slope cutouts from small and large grain BCP (buffered chemical polished) 1.5GHz cavities, before and after undergoing 120C UHV-bake. The results obtained will be presented, and it will be discussed in which future direction those results lead.

Slides TUIOB04 [4.621 MB]

THIOB06

Recents Developments in SRF at TRIUMF

685

R.E. Laxdal, C.D. Beard, A. Grassellino, P. Kolb, D. Longuevergne, V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
R.S. Orr, W. Trischuk
University of Toronto, Toronto, Ontario, Canada

The TRIUMF SRF program follows three basic paths: the support of the existing installed superconducting heavy ion linac with forty quarter wave cavities, the development of infrastructure and cavities for the new e-Linac project at 1.3GHz and fundamental studies to support student projects. Work on the quarter waves primarily involves determining optimum processing steps to improve cavity performance. The e-Linac cavity is a variant of the Tesla nine cell cavity modified to allow the acceleration of 10mA in cw mode. Fundamental studies on RRR niobium have been done at the Muon Spin Resonance facility at TRIUMF to characterize the flux of first entry for different processing of the niobium. THe program will be summarized.

Paper	Title	Page
MOPO017	Performance Limitation Studies on ISAC-II QWR’s and e-Linac Elliptical Cavities at TRIUMF	97
	D. Longuevergne, A. Grassellino, P. Kolb, R.E. Laxdal, V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	TRIUMF has been operating successfully for several years numerous 100MHz class superconducting quarter wave resonators on the ISAC-II heavy ion linac and is now developing a 1.3 GHz activity to build the e-linac, a 50 MeV superconducting electron linac to produce radioisotopes by photofission. Several studies on cavity treatments are ongoing to both enhance ISAC-II QWR performances and to meet the requirements on the e-linac elliptical cavities. This paper will summarize the main development efforts to understand performance limitations in these cavities.
	Poster MOPO017 [0.689 MB]

MOPO020	Nine-cell Elliptical Cavity Development at TRIUMF	107
	V. Zvyagintsev, C.D. Beard, A. Grassellino, D. Kaltchev, P. Kolb, R.E. Laxdal, D. Longuevergne, B.S. Waraich TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada M. Ahammed DAE/VECC, Calcutta, India R.O. Bolgov, N.P. Sobenin MEPhI, Moscow, Russia R. Edinger PAVAC, Richmond, B.C., Canada
	The superconducting e-Linac project at TRIUMF requires a new nine cell elliptical cavity at 1.3GHz of TESLA influenced design capable of providing a CW accelerating voltage of 10MV at 10mA of beam intensity. This corresponds to a challenging 100kW of beam loaded rf power and a Beam Break-up (BBU)threshold in multi-pass mode of Rd/Q*QL=10MOhms. For this purpose we use two opposed CPI 60kW cw rated couplers. Another challenge is to provide HOM damping for the possibility of multi-pass ERL operation by means of end cell optimization and higher order mode (HOM) dampers. Results of the cavity design work including developments toward a passive HOM damper will be discussed.

TUIOB04	Muon Spin Rotation/Relaxation Studies of Niobium for SRF applications	330
	A. Grassellino TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	One of the outstanding scientific issues related to superconducting radio frequency cavities made of high-purity bulk niobium is the occurrence of field dependent losses in the walls of the niobium cavity. These losses occur at different RF field levels and pose severe limitations to the niobium technology for both CW or pulsed applications. In this presentation I will explain the results of an experiment which focused on understanding the mechanisms behind losses in the high field regime (above 80-100mT peak magnetic fields). The problem was studied utilizing the unique TRIUMF muon spin rotation (muSR) facility to investigate superconducting properties of niobium samples. In particular, the muon spin rotation experiments aimed at studying the field of first flux entry in high field Q-slope cutouts from small and large grain BCP (buffered chemical polished) 1.5GHz cavities, before and after undergoing 120C UHV-bake. The results obtained will be presented, and it will be discussed in which future direction those results lead.
	Slides TUIOB04 [4.621 MB]

THIOB06	Recents Developments in SRF at TRIUMF	685
	R.E. Laxdal, C.D. Beard, A. Grassellino, P. Kolb, D. Longuevergne, V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada R.S. Orr, W. Trischuk University of Toronto, Toronto, Ontario, Canada
	The TRIUMF SRF program follows three basic paths: the support of the existing installed superconducting heavy ion linac with forty quarter wave cavities, the development of infrastructure and cavities for the new e-Linac project at 1.3GHz and fundamental studies to support student projects. Work on the quarter waves primarily involves determining optimum processing steps to improve cavity performance. The e-Linac cavity is a variant of the Tesla nine cell cavity modified to allow the acceleration of 10mA in cw mode. Fundamental studies on RRR niobium have been done at the Muon Spin Resonance facility at TRIUMF to characterize the flux of first entry for different processing of the niobium. THe program will be summarized.