PAC2013 - List of Authors (Morris, D.)

Paper	Title	Page
MOPMA20	Phase Stability of the RF Reference Line for the FRIB Linac	342
	Q. Zhao, J.F. Brandon NSCL, East Lansing, Michigan, USA D. Morris, Y. Yamazaki FRIB, East Lansing, Michigan, USA
	Funding: supported by the US Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The phase stability of rf reference line is usually quite restricted in a high energy linac (very long linac, very high frequency). Due to the change of the ambience temperature in the linac tunnel, the electrical length of reference rf cables may change significantly, which results in unacceptable phase changes in cavities. So, sometimes the reference line is very expensive, for example, made of optical fiber housed in a lengthy thermostatic chamber. The frequencies of FRIB linac cavities are 80.5 and 322 MHz (not very high). We also take advantage of the double-folded linac geometry and feed the reference line in the center of the linac to effectively reduced the reference line by 6 times. Our studies show that the FRIB linac can tolerate up to 12ps phase stability of the rf reference line. Therefore, no special treatment is needed for the reference line.

THPMA02	Study of Microphonics Compensation for SRF Cavity	1355
	Z. Zheng TUB, Beijing, People's Republic of China Z. Liu, D. Morris, J. Wei, Y. Zhang, S. Zhao FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Microphonics and Lorentz Force detune the resonance frequency of a SRF cavity, leading to perturbations of the amplitude and phase of its accelerating field. Although this disturbance could be compensated by a piezo-electric tuner or with additional RF power, these two methods have conflicts, which is observed as unstable RF fields in a recent experiment. These conflicts could be explained by a model. Further experiments on ReA3 [1] cryomodule validates a conflict suggested by the model. Overall optimization of control algorithm is still needed to effectively combine the two methods.

FRYBA1	Progress towards the Facility for Rare Isotope Beams	1453
	J. Wei, N.K. Bultman, F. Casagrande, C. Compton, K.D. Davidson, J. DeKamp, B. Drewyor, K. Elliott, A. Facco, P.E. Gibson, T . Glasmacher, K. Holland, M.J. Johnson, S. Jones, D. Leitner, M. Leitner, G. Machicoane, F. Marti, D. Morris, J.A. Nolen, J.P. Ozelis, S. Peng, J. Popielarski, L. Popielarski, E. Pozdeyev, T. Russo, K. Saito, J.J. Savino, R.C. Webber, M. Williams, T. Xu, Y. Yamazaki, A. Zeller, Y. Zhang, Q. Zhao FRIB, East Lansing, USA D. Arenius, V. Ganni JLAB, Newport News, Virginia, USA A. Facco INFN/LNL, Legnaro (PD), Italy R.E. Laxdal TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada J.A. Nolen ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams (FRIB) is based on a continuous-wave superconducting heavy ion linac to accelerate all the stable isotopes to above 200 MeV/u with a beam power of up to 400 kW. At an average beam power approximately two-to-three orders-of-magnitude higher than those of operating heavy-ion facilities, FRIB stands at the power frontier of the accelerator family - the first time for heavy-ion accelerators. To realize this innovative performance, superconducting RF cavities are used starting at the very low energy of 500 keV/u, and beams with multiple charge states are accelerated simultaneously. Many technological challenges specific for this linac have been tackled by the FRIB team and collaborators. Furthermore, the distinct differences from the other types of linacs at the power front must be clearly understood to make the FRIB successful. This report summarizes the technical progress made in the past years to meet these challenges.

Paper

Title

Page

Phase Stability of the RF Reference Line for the FRIB Linac

342

Q. Zhao, J.F. Brandon
NSCL, East Lansing, Michigan, USA
D. Morris, Y. Yamazaki
FRIB, East Lansing, Michigan, USA

Funding: supported by the US Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The phase stability of rf reference line is usually quite restricted in a high energy linac (very long linac, very high frequency). Due to the change of the ambience temperature in the linac tunnel, the electrical length of reference rf cables may change significantly, which results in unacceptable phase changes in cavities. So, sometimes the reference line is very expensive, for example, made of optical fiber housed in a lengthy thermostatic chamber. The frequencies of FRIB linac cavities are 80.5 and 322 MHz (not very high). We also take advantage of the double-folded linac geometry and feed the reference line in the center of the linac to effectively reduced the reference line by 6 times. Our studies show that the FRIB linac can tolerate up to 12ps phase stability of the rf reference line. Therefore, no special treatment is needed for the reference line.

THPMA02

Study of Microphonics Compensation for SRF Cavity

1355

Z. Zheng
TUB, Beijing, People's Republic of China
Z. Liu, D. Morris, J. Wei, Y. Zhang, S. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Microphonics and Lorentz Force detune the resonance frequency of a SRF cavity, leading to perturbations of the amplitude and phase of its accelerating field. Although this disturbance could be compensated by a piezo-electric tuner or with additional RF power, these two methods have conflicts, which is observed as unstable RF fields in a recent experiment. These conflicts could be explained by a model. Further experiments on ReA3 [1] cryomodule validates a conflict suggested by the model. Overall optimization of control algorithm is still needed to effectively combine the two methods.

FRYBA1

Progress towards the Facility for Rare Isotope Beams

1453

J. Wei, N.K. Bultman, F. Casagrande, C. Compton, K.D. Davidson, J. DeKamp, B. Drewyor, K. Elliott, A. Facco, P.E. Gibson, T . Glasmacher, K. Holland, M.J. Johnson, S. Jones, D. Leitner, M. Leitner, G. Machicoane, F. Marti, D. Morris, J.A. Nolen, J.P. Ozelis, S. Peng, J. Popielarski, L. Popielarski, E. Pozdeyev, T. Russo, K. Saito, J.J. Savino, R.C. Webber, M. Williams, T. Xu, Y. Yamazaki, A. Zeller, Y. Zhang, Q. Zhao
FRIB, East Lansing, USA
D. Arenius, V. Ganni
JLAB, Newport News, Virginia, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
R.E. Laxdal
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
J.A. Nolen
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) is based on a continuous-wave superconducting heavy ion linac to accelerate all the stable isotopes to above 200 MeV/u with a beam power of up to 400 kW. At an average beam power approximately two-to-three orders-of-magnitude higher than those of operating heavy-ion facilities, FRIB stands at the power frontier of the accelerator family - the first time for heavy-ion accelerators. To realize this innovative performance, superconducting RF cavities are used starting at the very low energy of 500 keV/u, and beams with multiple charge states are accelerated simultaneously. Many technological challenges specific for this linac have been tackled by the FRIB team and collaborators. Furthermore, the distinct differences from the other types of linacs at the power front must be clearly understood to make the FRIB successful. This report summarizes the technical progress made in the past years to meet these challenges.