SRF2011 - List of Authors (Rose, J.)

Paper

Title

Page

Design of a 1500 MHz Bunch Lengthening Cavity for NSLS-II

210

J. Rose, N.A. Towne
BNL, Upton, Long Island, New York, USA
C.H. Boulware, T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA

The NSLS-II is a new third generation light source being constructed at > BNL. In order to increase the Touschek lifetime and third harmonic bunch > lengthening cavity is required. A 1500 MHz passive third harmonic cavity has > been designed and fabricated. It is a coupled two-cell HOM damped SRF cavity > that can provide 1 MV of voltage in a single cryomodule. The two cell design > allows for a single tuner mechanism outside the cryostat while the room > temperature ferrite HOM dampers provide damping of all but the fundamental > zero and pi modes. Since the unwanted zero mode is strongly coupled to the > pi mode it tracks the pi mode tuning which is required for the beam induced > excitation. The design allows for the tuning of the pi mode between minimum > and required field excitation while keeping the zero mode excitation below > allowable limits. Design and initial cold test results are presented.

TUPO035

Cryogenic Test of a Two-Cell Passive SRF Cavity for NSLS-II

459

C.H. Boulware, T.L. Grimm, C. Krizmanich, B. Kuhlman, N. Miller, B. Siegel, M.J. Winowski
Niowave, Inc., Lansing, Michigan, USA
W.K. Gash, B.N. Kosciuk, V. Ravindranath, J. Rose, S.K. Sharma, R. Sikora, N.A. Towne
BNL, Upton, Long Island, New York, USA

Funding: The work at Niowave has been funded by DOE SBIR grant DE-FG02-08ER85014.
In collaboration with Brookhaven National Lab (BNL), Niowave, Inc. has built and performed the first cryogenic test on a two-cell passive SRF cavity for controlling electron bunch lengths at NSLS-II, the new 3rd generation synchrotron under construction at BNL. The structure is resonant at 1500 MHz, the third harmonic of the accelerating RF frequency. Because the cavity is powered by the beam itself, however, many frequencies could potentially be excited and higher-order modes must be strongly damped. Further, only one of the two cavity fundamental modes is used for the bunch length control, and the other mode has been carefully tuned so that it will be minimally excited by the electron bunches. The first cryogenic test has been performed to demonstrate a successful cooldown of the cavity in its cryomodule and to show that the cavity can be tuned to its operating frequency while the proper spacing between the two fundamental modes is maintained. A brief discussion of the cavity design will be presented along with some results from the cavity tuning and cryotest.

Poster TUPO035 [1.092 MB]

Paper	Title	Page
MOPO050	Design of a 1500 MHz Bunch Lengthening Cavity for NSLS-II	210
	J. Rose, N.A. Towne BNL, Upton, Long Island, New York, USA C.H. Boulware, T.L. Grimm Niowave, Inc., Lansing, Michigan, USA
	The NSLS-II is a new third generation light source being constructed at > BNL. In order to increase the Touschek lifetime and third harmonic bunch > lengthening cavity is required. A 1500 MHz passive third harmonic cavity has > been designed and fabricated. It is a coupled two-cell HOM damped SRF cavity > that can provide 1 MV of voltage in a single cryomodule. The two cell design > allows for a single tuner mechanism outside the cryostat while the room > temperature ferrite HOM dampers provide damping of all but the fundamental > zero and pi modes. Since the unwanted zero mode is strongly coupled to the > pi mode it tracks the pi mode tuning which is required for the beam induced > excitation. The design allows for the tuning of the pi mode between minimum > and required field excitation while keeping the zero mode excitation below > allowable limits. Design and initial cold test results are presented.

TUPO035	Cryogenic Test of a Two-Cell Passive SRF Cavity for NSLS-II	459
	C.H. Boulware, T.L. Grimm, C. Krizmanich, B. Kuhlman, N. Miller, B. Siegel, M.J. Winowski Niowave, Inc., Lansing, Michigan, USA W.K. Gash, B.N. Kosciuk, V. Ravindranath, J. Rose, S.K. Sharma, R. Sikora, N.A. Towne BNL, Upton, Long Island, New York, USA
	Funding: The work at Niowave has been funded by DOE SBIR grant DE-FG02-08ER85014. In collaboration with Brookhaven National Lab (BNL), Niowave, Inc. has built and performed the first cryogenic test on a two-cell passive SRF cavity for controlling electron bunch lengths at NSLS-II, the new 3rd generation synchrotron under construction at BNL. The structure is resonant at 1500 MHz, the third harmonic of the accelerating RF frequency. Because the cavity is powered by the beam itself, however, many frequencies could potentially be excited and higher-order modes must be strongly damped. Further, only one of the two cavity fundamental modes is used for the bunch length control, and the other mode has been carefully tuned so that it will be minimally excited by the electron bunches. The first cryogenic test has been performed to demonstrate a successful cooldown of the cavity in its cryomodule and to show that the cavity can be tuned to its operating frequency while the proper spacing between the two fundamental modes is maintained. A brief discussion of the cavity design will be presented along with some results from the cavity tuning and cryotest.
	Poster TUPO035 [1.092 MB]