IPAC2012 - List of Authors (Rimmer, R.A.)

Paper	Title	Page
MOPPD016	Status of Proof-of-principle Experiment for Coherent Electron Cooling	400
	I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko BNL, Upton, Long Island, New York, USA G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz Tech-X, Boulder, Colorado, USA A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer JLAB, Newport News, Virginia, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia
	Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231. Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

WEPPC042	Low Impedance Bellows for High-current Beam Operations	2303
	G. Wu, K.-J. Kim, A. Nassiri, G.J. Waldschmidt, Y. Yang ANL, Argonne, USA J.J. Feingold, J.D. Mammosser, R.A. Rimmer, H. Wang JLAB, Newport News, Virginia, USA J. Jang, S.H. Kim POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: Work Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357 In particle accelerators, bellows are commonly used to connect beamline components. Such bellows are traditionally shielded to lower the beam impedance. Excessive beam impedance can cause overheating in the bellows, especially in high beam current operation. For an SRF-based accelerator, the bellows must also be particulate free. Many designs of shielded bellows incorporate rf slides or fingers that prevent convolutions from being exposed to wakefields. Unfortunately these mechanical structures tend to generate particulates that, if left in the SRF accelerator, can migrate into superconducting cavities, the accelerator's critical components. In this paper, we describe a prototype unshielded bellows that has low beam impedance and no risk of particulate generation.

WEPPC086	Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule	2414
	L. Xiao, Z. Li, C.-K. Ng SLAC, Menlo Park, California, USA A. Nassiri, G.J. Waldschmidt, G. Wu ANL, Argonne, USA R.A. Rimmer, H. Wang JLAB, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.

WEPPC038	Status of the Short-Pulse X-ray Project at the Advanced Photon Source	2292
	A. Nassiri, N.D. Arnold, T.G. Berenc, M. Borland, B. Brajuskovic, D.J. Bromberek, J. Carwardine, G. Decker, L. Emery, J.D. Fuerst, A.E. Grelick, D. Horan, J. Kaluzny, F. Lenkszus, R.M. Lill, J. Liu, H. Ma, V. Sajaev, T.L. Smith, B.K. Stillwell, G.J. Waldschmidt, G. Wu, B.X. Yang, Y. Yang, A. Zholents ANL, Argonne, USA J.M. Byrd, L.R. Doolittle, G. Huang LBNL, Berkeley, California, USA G. Cheng, G. Ciovati, P. Dhakal, G.V. Eremeev, J.J. Feingold, R.L. Geng, J. Henry, P. Kneisel, K. Macha, J.D. Mammosser, J. Matalevich, A.D. Palczewski, R.A. Rimmer, H. Wang, K.M. Wilson, M. Wiseman JLAB, Newport News, Virginia, USA Z. Li, L. Xiao SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source Upgrade (APS-U) Project at Argonne will include generation of short-pulse x-rays based on Zholents’* deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. In collaboration with Jefferson Laboratory, we are prototyping and testing a number of single-cell deflecting cavities and associated auxiliary systems with promising initial results. In collaboration with Lawrence Berkeley National Laboratory, we are working to develop state-of-the-art timing, synchronization, and differential rf phase stability systems that are required for SPX. Collaboration with Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi-cavity geometries with lower- and higher-order modes waveguide dampers using ACE3P. This contribution provides the current R&D status of the SPX project. * A. Zholents et al., NIM A 425, 385 (1999).

THPPC029	High-power Waveguide Dampers for the Short-Pulse X-Ray Project at the Advanced Photon Source	3344
	G.J. Waldschmidt, B. Brajuskovic, J. Liu, M.E. Middendorf, A. Nassiri, T.L. Smith, G. Wu ANL, Argonne, USA J. Henry, J.D. Mammosser, R.A. Rimmer, M. Wiseman JLAB, Newport News, Virginia, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. High-power waveguide dampers have been designed and prototyped for the Short-Pulse X-ray (SPX) cavities at the Advanced Photon Source. The cavities will operate at 2.815 GHz and utilize the TM110 dipole mode. As a result, higher-order (HOM) and lower-order mode (LOM) in-vacuum dampers have been designed to satisfy the demanding broadband damping requirements in the APS storage ring. The SPX single-cell cavity consists of two WR284 waveguides for damping the HOMs and one WR284 waveguide for primarily damping the LOM where up to 2kW will be dissipated in the damping material. The damper designs and high-power experimental results will be discussed in this paper.

Paper

Title

Page

Status of Proof-of-principle Experiment for Coherent Electron Cooling

400

I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko
BNL, Upton, Long Island, New York, USA
G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia

Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231.
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

WEPPC042

Low Impedance Bellows for High-current Beam Operations

2303

G. Wu, K.-J. Kim, A. Nassiri, G.J. Waldschmidt, Y. Yang
ANL, Argonne, USA
J.J. Feingold, J.D. Mammosser, R.A. Rimmer, H. Wang
JLAB, Newport News, Virginia, USA
J. Jang, S.H. Kim
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Work Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357
In particle accelerators, bellows are commonly used to connect beamline components. Such bellows are traditionally shielded to lower the beam impedance. Excessive beam impedance can cause overheating in the bellows, especially in high beam current operation. For an SRF-based accelerator, the bellows must also be particulate free. Many designs of shielded bellows incorporate rf slides or fingers that prevent convolutions from being exposed to wakefields. Unfortunately these mechanical structures tend to generate particulates that, if left in the SRF accelerator, can migrate into superconducting cavities, the accelerator's critical components. In this paper, we describe a prototype unshielded bellows that has low beam impedance and no risk of particulate generation.

WEPPC086

Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule

2414

L. Xiao, Z. Li, C.-K. Ng
SLAC, Menlo Park, California, USA
A. Nassiri, G.J. Waldschmidt, G. Wu
ANL, Argonne, USA
R.A. Rimmer, H. Wang
JLAB, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.

WEPPC038

Status of the Short-Pulse X-ray Project at the Advanced Photon Source

2292

A. Nassiri, N.D. Arnold, T.G. Berenc, M. Borland, B. Brajuskovic, D.J. Bromberek, J. Carwardine, G. Decker, L. Emery, J.D. Fuerst, A.E. Grelick, D. Horan, J. Kaluzny, F. Lenkszus, R.M. Lill, J. Liu, H. Ma, V. Sajaev, T.L. Smith, B.K. Stillwell, G.J. Waldschmidt, G. Wu, B.X. Yang, Y. Yang, A. Zholents
ANL, Argonne, USA
J.M. Byrd, L.R. Doolittle, G. Huang
LBNL, Berkeley, California, USA
G. Cheng, G. Ciovati, P. Dhakal, G.V. Eremeev, J.J. Feingold, R.L. Geng, J. Henry, P. Kneisel, K. Macha, J.D. Mammosser, J. Matalevich, A.D. Palczewski, R.A. Rimmer, H. Wang, K.M. Wilson, M. Wiseman
JLAB, Newport News, Virginia, USA
Z. Li, L. Xiao
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source Upgrade (APS-U) Project at Argonne will include generation of short-pulse x-rays based on Zholents’* deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. In collaboration with Jefferson Laboratory, we are prototyping and testing a number of single-cell deflecting cavities and associated auxiliary systems with promising initial results. In collaboration with Lawrence Berkeley National Laboratory, we are working to develop state-of-the-art timing, synchronization, and differential rf phase stability systems that are required for SPX. Collaboration with Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi-cavity geometries with lower- and higher-order modes waveguide dampers using ACE3P. This contribution provides the current R&D status of the SPX project.
* A. Zholents et al., NIM A 425, 385 (1999).

THPPC029

High-power Waveguide Dampers for the Short-Pulse X-Ray Project at the Advanced Photon Source

3344

G.J. Waldschmidt, B. Brajuskovic, J. Liu, M.E. Middendorf, A. Nassiri, T.L. Smith, G. Wu
ANL, Argonne, USA
J. Henry, J.D. Mammosser, R.A. Rimmer, M. Wiseman
JLAB, Newport News, Virginia, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
High-power waveguide dampers have been designed and prototyped for the Short-Pulse X-ray (SPX) cavities at the Advanced Photon Source. The cavities will operate at 2.815 GHz and utilize the TM110 dipole mode. As a result, higher-order (HOM) and lower-order mode (LOM) in-vacuum dampers have been designed to satisfy the demanding broadband damping requirements in the APS storage ring. The SPX single-cell cavity consists of two WR284 waveguides for damping the HOMs and one WR284 waveguide for primarily damping the LOM where up to 2kW will be dissipated in the damping material. The damper designs and high-power experimental results will be discussed in this paper.