IPAC2012 - List of Authors (Stillwell, B.K.)

Paper	Title	Page
MOPPP080	New Concepts for Revolver Undulator Designs	750
	B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg ANL, Argonne, USA M.B. Patil Impact Engineering Solutions, Brookfield, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation.

WEPPC040	Evaluation of VATSEAL Technology to Seal Waveguide Serving High-field Superconducting RF Cavities	2298
	B.K. Stillwell, J.D. Fuerst, J. Liu, G.J. Waldschmidt, G. Wu ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A waveguide flange seal serving a high-field, superconducting, radio-frequency (SRF) cavity ideally possesses several characteristics. Seals must generally be ultrahigh-vacuum leak tight. Seals must also bridge the inner surfaces of connecting flanges for optimum transmission and minimal heating due to trapped modes. In addition, if seal contact areas are minimized, flange seals may serve as convenient thermal impedances. Finally, seals must be easily cleanable and not be prone to generate particulate matter during assembly and disassembly. A unique sealing technology known as VATSEAL may neatly address all of the above requirements. In this paper, we describe our evaluation of VATSEAL technology for use in SRF cavity assemblies.

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).

Paper

Title

Page

New Concepts for Revolver Undulator Designs

750

B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg
ANL, Argonne, USA
M.B. Patil
Impact Engineering Solutions, Brookfield, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation.

WEPPC040

Evaluation of VATSEAL Technology to Seal Waveguide Serving High-field Superconducting RF Cavities

2298

B.K. Stillwell, J.D. Fuerst, J. Liu, G.J. Waldschmidt, G. Wu
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A waveguide flange seal serving a high-field, superconducting, radio-frequency (SRF) cavity ideally possesses several characteristics. Seals must generally be ultrahigh-vacuum leak tight. Seals must also bridge the inner surfaces of connecting flanges for optimum transmission and minimal heating due to trapped modes. In addition, if seal contact areas are minimized, flange seals may serve as convenient thermal impedances. Finally, seals must be easily cleanable and not be prone to generate particulate matter during assembly and disassembly. A unique sealing technology known as VATSEAL may neatly address all of the above requirements. In this paper, we describe our evaluation of VATSEAL technology for use in SRF cavity assemblies.

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).