NAPAC2016 - List of Keywords (impedance)

Paper	Title	Other Keywords	Page
MOPOB11	Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project	ion, photon, vacuum, storage-ring	92
	B.K. Stillwell, B. Brajuskovic, J.A. Carter, H. Cease, R.M. Lill, G. Navrotski, J. R. Noonan, K.J. Suthar, D.R. Walters, G.E. Wiemerslage, J. Zientek ANL, Argonne, Illinois, USA M.P. Sangroula IIT, Chicago, Illinois, USA
	Funding: UChicago Argonne, LLC, operator of Argonne National Laboratory, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Upgrade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation, insufficient beam position monitor stability, excessive beam impedance, excessive heating by induced electrical surface currents, and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mock-up assemblies, performing mechanical testing of chamber weld joints, developing computational tools, investigating design alternatives, and performing electrical bench measurements. Status of these activities and some of what has been learned to date will be shared. *B. Stillwell et al., Conceptual Design of a Storage Ring Vacuum System Compatible with Implementation of a Seven Bend Achromat Lattice at the APS, in Proc. IPAC'14, Dresden, Germany, 2409-2411.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB11
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB16	Higher Order Modes Analysis of Fermilab's Recycler Cavity	cavity, ion, dipole, HOM	106
	M.H. Awida, J.E. Dey, T.N. Khabiboulline, V.A. Lebedev, R.L. Madrak Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Two recycler cavities are being employed in Fermilab's Recycler Ring for the purpose of slip stacking proton bunches, where 6 batches of 8 GeV protons coming from the Booster are stacked on top of 6 circulating batches. Slip stacking requires two RF cavities operating at 52.809 and 51.545 MHz. In this paper, we report on the analysis of higher order modes in the Recycler cavity, presenting the values for R/Q and shunt impedances. Knowing the frequencies and properties of higher order modes is particularly critical for beam physics and avoidance of beam instabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB16
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB47	Beam Coupling Impedance Characterization of Third Harmonic Cavity for ALS Upgrade	ion, cavity, HOM, coupling	167
	T.H. Luo, K.M. Baptiste, M. Betz, J.M. Byrd, S. De Santis, S. Kwiatkowski, S. Persichelli, Y. Yang LBNL, Berkeley, California, USA
	The ALS upgrade to a diffraction-limited light source (ALS-U) depends on the ability to lengthen the stored bunches to limit the emittance growth and increase the beam life time. In order to achieve lengthening in excess of fourfold necessary to this end, we are investigating the use of the same passive 1.5 GHz normal-conducting RF cavities currently used on the ALS. While the upgraded ring RF parameters and fill pattern make it easier as long as the beam-induced phase transient is concerned, the large lengthening factor and the strongly non-linear lattice require particular attention to the cavities contribution to the machine overall impedance budget. In this paper we present our estimates of the narrow-band impedance obtained by numerical simulation and bench measurements of the cavities' resonant modes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB47
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB57	Wakefield Excitation in Power Extraction Cavity of Co-Linear X-Band Energy Booster in Time Domain With ACE3P	ion, cavity, wakefield, extraction	195
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	We provide the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB). Here, using the time domain solver T3P of the ACE3P Suite we provide the single bunch and multiple bunch wakefield excitation mechanism for the power build up when using a symmetric Gaussian bunch distribution in our traveling wave (TW) X-band power extraction cavity (PEC). Finally, we determine the achievable X-band power at the end of the PEC structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB57
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUB1CO03	ALS-U: A Soft X-Ray Diffraction Limited Light Source	ion, emittance, undulator, injection	263
	C. Steier, A. Anders, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, H. Nishimura, T. Oliver, J.R. Osborn, H.A. Padmore, G.C. Pappas, S. Persichelli, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan, Y.C. Yang LBNL, Berkeley, California, USA
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source (ALS-U). The upgrade proposal will reuse much of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. We will report on the accelerator design progress as well as the details of the ongoing R+D program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB1CO03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUB2CO03	Fokker-Planck Analysis of Transverse Collective Instabilities in Electron Storage Rings	ion, damping, simulation, synchrotron	290
	R.R. Lindberg ANL, Argonne, Illinois, USA
	Funding: U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357 We analyze single bunch transverse instabilities due to wakefields using a Fokker-Planck model. We expand on the work of Suzuki, writing out the linear matrix equation including chromaticity, both dipolar and quadrupolar transverse wakefields, and the effects of damping and diffusion due to the synchrotron radiation. The eigenvalues and eigenvectors determine the collective stability of the beam, and we show that the predicted threshold current for transverse instability and the profile of the unstable agree well with tracking simulations. In particular, we find that predicting collective stability for high energy electron beams at moderate to large values of chromaticity requires the full Fokker-Planck analysis to properly account for the effects of damping and diffusion due to synchrotron radiation. T. Suzuki, Particle Accel., 12, 237 (1982)
	Slides TUB2CO03 [1.717 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB2CO03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOB40	Fundamental Properties of a Novel, Metal-Dielectric, Tubular Structure with Magnetic RF Compensation	ion, linac, coupling, simulation	582
	A.V. Smirnov RadiaBeam Systems, Santa Monica, California, USA E.A. Savin MEPhI, Moscow, Russia
	Funding: Supported by DoE Contract # DE-SC0011370 A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev's disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c-0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.
	Poster TUPOB40 [1.447 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB40
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOB50	Beam-Induced Heating of the Kicker Ceramics Chambers at NSLS-II	ion, kicker, ECR, injection	599
	A. Blednykh, B. Bacha, G. Bassi, G. Ganetis, C. Hetzel, H.-C. Hseuh, T.V. Shaftan, V.V. Smaluk, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-98CH10886. First experience with the beam-induced heating of the ceramics chambers in the NSLS-II storage ring has been discussed. Total five ceramics chambers are considered to be replaced due to overheating concern during of upcoming I_av=500mA operations. The air cooling fans has been installed as a temporarily solution to remove heat.
	Poster TUPOB50 [1.629 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB50
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOA14	Resistive Wall Growth Rate Measurements in the Fermilab Recycler	ion, cavity, operation, injection	719
	R. Ainsworth, P. Adamson, A.V. Burov, I. Kourbanis Fermilab, Batavia, Illinois, USA
	Impedance could represent a limitation of running high intensity beams in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this, studies have been performed measuring the growth rate of presumably the resistive wall instability. The growth rates at varying intensities and chromaticities are shown. The measured growth rates are compared to ones calculated with the resistive wall impedance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA14
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3CO04	Impedance Characterization and Collective Effects in the MAX IV 3 GeV Ring	ion, synchrotron, feedback, experiment	843
	G. Skripka, Å. Andersson, P.F. Tavares MAX IV Laboratory, Lund University, Lund, Sweden F.J. Cullinan, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	Collective instabilities in the MAX IV 3 GeV storage ring are enhanced by the combination of high beam current, ultralow emittance and small vacuum chamber aperture. To mitigate instabilities by Landau damping and improve lifetime three passive harmonic cavities are installed to introduce synchrotron tune spread and bunch lengthening respectively. We present the results of studies of collective effects driven by the machine impedance. Bunch lengthening and detuning were measured to characterize the effective impedance and estimate the effect of the harmonic cavity potential. Investigations of collective effects as a function of parameters such as beam current and chromaticity are discussed.
	Slides WEA3CO04 [3.845 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA3CO04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB16	Simulation Studies of a Prototype Stripline Kicker for the APS-MBA Upgrade	kicker, ion, simulation, high-voltage	928
	X. Sun, C. Yao ANL, Argonne, Illinois, USA
	Funding: *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. A prototype dual-blade stripline kicker for the APS multi-bend achromat (MBA) upgrade has been designed and developed. It was optimized with 3D CST Micro-wave Studio. The high voltage (HV) feedthrough and air-side connector were designed and optimized. The elec-tromagnetic fields along the beam path, deflecting angle and high electric fields with their locations were calculat-ed with 15 kV differential pulse voltage applied to the kicker blades through the feedthroughs. The beam im-pedance and power dissipation on different parts of the kicker and external loads were studied for a 48-bunch fill pattern. Our simulation results show that the prototype kicker with its HV feedthroughs meets the specified re-quirements. The results of TDR (time-domain reflectome-ter) test, high voltage pulse test and beam test of the pro-totype kicker assembly agreed with the simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB16
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB24	Preliminary Test Results of a Prototype Fast Kicker for APS MBA Upgrade	kicker, ion, simulation, high-voltage	950
	C. Yao, A. Barcikowski, A.R. Brill, J. Carwardine, T.K. Clute, Z.A. Conway, A.R. Cours, G. Decker, R.T. Keane, F. Lenkszus, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The APS multi-bend achromatic (MBA) upgrade storage ring plans to support two bunch fill patterns: a 48-bunch and a 324-bunch. A "swap out" injection scheme is required. In order provide the required kick to injected beam, to minimize the beam loss and residual oscillation of injected beam, and to minimize the perturbation to stored beam during injection, the rise, fall, and flat-top parts of the kicker pulse must be within a 16.9-ns interval. Stripling-type kickers are chosen for both injection and extraction. We developed a prototype kicker that supports a ±15kV differential pulse voltage. We performed high voltage discharge, TDR measurement, high voltage pulse test and beam test of the kicker. We report the design of the fast kicker and the test results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB24
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB69	Impedance Simulation for LEReC Booster Cavity Transformed from ERL Gun Cavity	ion, cavity, simulation, booster	1048
	C. Liu BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Wake impedance induced energy spread is a concern for the electron beam to be used for electron cooling of the low energy ion beams in RHIC. The impedance simulation of the booster cavity for the Low Energy RHIC electron cooling (LEReC) project is presented in this report. The simulation is done for both non-relativistic and ultra-relativistic cases. The space charge impedance in the first case is discussed. For an impedance budget consideration of the electron machine only a simulation of the geometrical impedance in the latter case is necessary since space charge is considered separately.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB69
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2IO01	Specifics of Electron Dynamics in High Energy Circular e⁺e⁻ Colliders	ion, collider, sextupole, luminosity	1071
	Q. Qin, J. Gao, H. Geng, P. He, D. Wang, N. Wang, Y. Wang, Y. Zhang IHEP, Beijing, People's Republic of China
	At the energies envisioned for the FCC-ee the synchrotron radiation produces not only closed orbit effects but also some dynamics effects including strong "beta-synchrotron" coupling due to radiation in the final focus quadrupoles. Past experience with LEP and other machines as well as the implications for the new wave of circular electron collider proposals will be discussed.
	Slides THA2IO01 [6.536 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THA2IO01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA30	SCHARGEV 1.0 - Strong Space Charge Vlasov Solver	ion, space-charge, dipole, feedback	1164
	T. Zolkin, A.V. Burov Fermilab, Batavia, Illinois, USA
	The space charge (SC) is known to be one of the major limitations for the collective transverse beam stability. When space charge is strong, i.e. SC tune shift much greater than synchrotron tune, the problem allows an exact analytical solution. For that practically important case we present a fast and effective Vlasov solver SCHARGEV (Space CHARGE Vlasov) which calculates a complete eigensystem (spatial shapes of modes and frequency spectra) and therefore provides the growth rates and the thresholds of instabilities. SCHARGEV 1.0 includes driving and detuning wake forces, and, any feedback system (damper). In the next version we will include coupled bunch interaction and Landau damping. Numerical examples for FermiLab Recycler and CERN SPS are presented.
	Poster THPOA30 [1.493 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA30
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA33	A Preliminary Beam Impedance Model of the Advanced Light Source Upgrade at LBL	ion, cavity, vacuum, simulation	1174
	S. Persichelli, J.M. Byrd, S. De Santis, D. Li, T.H. Luo, J.R. Osborn, C.A. Swenson, M. Venturini, Y. Yang LBNL, Berkeley, California, USA
	The proposed upgrade of the Advanced Light Source (ALS-U) consists of a multi-bend achromat ultralow emittance lattice optimized for the production of diffraction-limited soft x-rays. A narrow-aperture vacuum chamber is a key feature of the new generation of light sources, and can result in a significant increase in the beam impedance, potentially limiting the maximum achievable beam current. While the conceptual design of the vacuum system is still in a very early development stage, this paper presents a preliminary estimate of the beam impedance using a combination of electromagnetic simulations and analytical calculations. We include the impedance of cavities, select vacuum-chamber components and resistive wall in a multi-layered beam chamber with NEG coating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA33
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA60	Status of PLSII Operation	ion, insertion, insertion-device, operation	1223
	T.-Y. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	As the upgrade of PLS, PLSII is a 3 GeV light source in 12 super-periods (281.8 m circumference) with 5.8 nm design emittance and can store electron beam up to 400 mA with 3 superconducting RF cavities. Its most unique characteristic is that it has a short straight section and a long straight section for each cell (24 straight sections) and up to 20 insertion devices can be installed. But, as the installed insertion devices, particularly in-vacuum insertion devices, are sources of high impedance, these are quite challenging for high current operation. Current status of PLSII operation and future plans are described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA60
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPOB11

Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

ion, photon, vacuum, storage-ring

92

B.K. Stillwell, B. Brajuskovic, J.A. Carter, H. Cease, R.M. Lill, G. Navrotski, J. R. Noonan, K.J. Suthar, D.R. Walters, G.E. Wiemerslage, J. Zientek
ANL, Argonne, Illinois, USA
M.P. Sangroula
IIT, Chicago, Illinois, USA

Funding: UChicago Argonne, LLC, operator of Argonne National Laboratory, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.
A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Upgrade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation, insufficient beam position monitor stability, excessive beam impedance, excessive heating by induced electrical surface currents, and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mock-up assemblies, performing mechanical testing of chamber weld joints, developing computational tools, investigating design alternatives, and performing electrical bench measurements. Status of these activities and some of what has been learned to date will be shared.
*B. Stillwell et al., Conceptual Design of a Storage Ring Vacuum System Compatible with Implementation of a Seven Bend Achromat Lattice at the APS, in Proc. IPAC'14, Dresden, Germany, 2409-2411.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB11

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB16

Higher Order Modes Analysis of Fermilab's Recycler Cavity

cavity, ion, dipole, HOM

106

M.H. Awida, J.E. Dey, T.N. Khabiboulline, V.A. Lebedev, R.L. Madrak
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Two recycler cavities are being employed in Fermilab's Recycler Ring for the purpose of slip stacking proton bunches, where 6 batches of 8 GeV protons coming from the Booster are stacked on top of 6 circulating batches. Slip stacking requires two RF cavities operating at 52.809 and 51.545 MHz. In this paper, we report on the analysis of higher order modes in the Recycler cavity, presenting the values for R/Q and shunt impedances. Knowing the frequencies and properties of higher order modes is particularly critical for beam physics and avoidance of beam instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB16

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB47

Beam Coupling Impedance Characterization of Third Harmonic Cavity for ALS Upgrade

ion, cavity, HOM, coupling

167

T.H. Luo, K.M. Baptiste, M. Betz, J.M. Byrd, S. De Santis, S. Kwiatkowski, S. Persichelli, Y. Yang
LBNL, Berkeley, California, USA

The ALS upgrade to a diffraction-limited light source (ALS-U) depends on the ability to lengthen the stored bunches to limit the emittance growth and increase the beam life time. In order to achieve lengthening in excess of fourfold necessary to this end, we are investigating the use of the same passive 1.5 GHz normal-conducting RF cavities currently used on the ALS. While the upgraded ring RF parameters and fill pattern make it easier as long as the beam-induced phase transient is concerned, the large lengthening factor and the strongly non-linear lattice require particular attention to the cavities contribution to the machine overall impedance budget. In this paper we present our estimates of the narrow-band impedance obtained by numerical simulation and bench measurements of the cavities' resonant modes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB47

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOB57

Wakefield Excitation in Power Extraction Cavity of Co-Linear X-Band Energy Booster in Time Domain With ACE3P

ion, cavity, wakefield, extraction

195

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

We provide the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB). Here, using the time domain solver T3P of the ACE3P Suite we provide the single bunch and multiple bunch wakefield excitation mechanism for the power build up when using a symmetric Gaussian bunch distribution in our traveling wave (TW) X-band power extraction cavity (PEC). Finally, we determine the achievable X-band power at the end of the PEC structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB57

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUB1CO03

ALS-U: A Soft X-Ray Diffraction Limited Light Source

ion, emittance, undulator, injection

263

C. Steier, A. Anders, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, H. Nishimura, T. Oliver, J.R. Osborn, H.A. Padmore, G.C. Pappas, S. Persichelli, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan, Y.C. Yang
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source (ALS-U). The upgrade proposal will reuse much of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. We will report on the accelerator design progress as well as the details of the ongoing R+D program.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB1CO03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUB2CO03

Fokker-Planck Analysis of Transverse Collective Instabilities in Electron Storage Rings

ion, damping, simulation, synchrotron

290

R.R. Lindberg
ANL, Argonne, Illinois, USA

Funding: U.S. Dept. of Energy Office of Sciences under Contract No. DE-AC02-06CH11357
We analyze single bunch transverse instabilities due to wakefields using a Fokker-Planck model. We expand on the work of Suzuki*, writing out the linear matrix equation including chromaticity, both dipolar and quadrupolar transverse wakefields, and the effects of damping and diffusion due to the synchrotron radiation. The eigenvalues and eigenvectors determine the collective stability of the beam, and we show that the predicted threshold current for transverse instability and the profile of the unstable agree well with tracking simulations. In particular, we find that predicting collective stability for high energy electron beams at moderate to large values of chromaticity requires the full Fokker-Planck analysis to properly account for the effects of damping and diffusion due to synchrotron radiation.
* T. Suzuki, Particle Accel., 12, 237 (1982)

Slides TUB2CO03 [1.717 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB2CO03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOB40

Fundamental Properties of a Novel, Metal-Dielectric, Tubular Structure with Magnetic RF Compensation

ion, linac, coupling, simulation

582

A.V. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: Supported by DoE Contract # DE-SC0011370
A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev's disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c-0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.

Poster TUPOB40 [1.447 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB40

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOB50

Beam-Induced Heating of the Kicker Ceramics Chambers at NSLS-II

ion, kicker, ECR, injection

599

A. Blednykh, B. Bacha, G. Bassi, G. Ganetis, C. Hetzel, H.-C. Hseuh, T.V. Shaftan, V.V. Smaluk, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by Department of Energy contract DE-AC02-98CH10886.
First experience with the beam-induced heating of the ceramics chambers in the NSLS-II storage ring has been discussed. Total five ceramics chambers are considered to be replaced due to overheating concern during of upcoming I_av=500mA operations. The air cooling fans has been installed as a temporarily solution to remove heat.

Poster TUPOB50 [1.629 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB50

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOA14

Resistive Wall Growth Rate Measurements in the Fermilab Recycler

ion, cavity, operation, injection

719

R. Ainsworth, P. Adamson, A.V. Burov, I. Kourbanis
Fermilab, Batavia, Illinois, USA

Impedance could represent a limitation of running high intensity beams in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this, studies have been performed measuring the growth rate of presumably the resistive wall instability. The growth rates at varying intensities and chromaticities are shown. The measured growth rates are compared to ones calculated with the resistive wall impedance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA14

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3CO04

Impedance Characterization and Collective Effects in the MAX IV 3 GeV Ring

ion, synchrotron, feedback, experiment

843

G. Skripka, Å. Andersson, P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden
F.J. Cullinan, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

Collective instabilities in the MAX IV 3 GeV storage ring are enhanced by the combination of high beam current, ultralow emittance and small vacuum chamber aperture. To mitigate instabilities by Landau damping and improve lifetime three passive harmonic cavities are installed to introduce synchrotron tune spread and bunch lengthening respectively. We present the results of studies of collective effects driven by the machine impedance. Bunch lengthening and detuning were measured to characterize the effective impedance and estimate the effect of the harmonic cavity potential. Investigations of collective effects as a function of parameters such as beam current and chromaticity are discussed.

Slides WEA3CO04 [3.845 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA3CO04

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB16

Simulation Studies of a Prototype Stripline Kicker for the APS-MBA Upgrade

kicker, ion, simulation, high-voltage

928

X. Sun, C. Yao
ANL, Argonne, Illinois, USA

Funding: *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
A prototype dual-blade stripline kicker for the APS multi-bend achromat (MBA) upgrade has been designed and developed. It was optimized with 3D CST Micro-wave Studio. The high voltage (HV) feedthrough and air-side connector were designed and optimized. The elec-tromagnetic fields along the beam path, deflecting angle and high electric fields with their locations were calculat-ed with 15 kV differential pulse voltage applied to the kicker blades through the feedthroughs. The beam im-pedance and power dissipation on different parts of the kicker and external loads were studied for a 48-bunch fill pattern. Our simulation results show that the prototype kicker with its HV feedthroughs meets the specified re-quirements. The results of TDR (time-domain reflectome-ter) test, high voltage pulse test and beam test of the pro-totype kicker assembly agreed with the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB16

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB24

Preliminary Test Results of a Prototype Fast Kicker for APS MBA Upgrade

kicker, ion, simulation, high-voltage

950

C. Yao, A. Barcikowski, A.R. Brill, J. Carwardine, T.K. Clute, Z.A. Conway, A.R. Cours, G. Decker, R.T. Keane, F. Lenkszus, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The APS multi-bend achromatic (MBA) upgrade storage ring plans to support two bunch fill patterns: a 48-bunch and a 324-bunch. A "swap out" injection scheme is required. In order provide the required kick to injected beam, to minimize the beam loss and residual oscillation of injected beam, and to minimize the perturbation to stored beam during injection, the rise, fall, and flat-top parts of the kicker pulse must be within a 16.9-ns interval. Stripling-type kickers are chosen for both injection and extraction. We developed a prototype kicker that supports a ±15kV differential pulse voltage. We performed high voltage discharge, TDR measurement, high voltage pulse test and beam test of the kicker. We report the design of the fast kicker and the test results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB24

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB69

Impedance Simulation for LEReC Booster Cavity Transformed from ERL Gun Cavity

ion, cavity, simulation, booster

1048

C. Liu
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Wake impedance induced energy spread is a concern for the electron beam to be used for electron cooling of the low energy ion beams in RHIC. The impedance simulation of the booster cavity for the Low Energy RHIC electron cooling (LEReC) project is presented in this report. The simulation is done for both non-relativistic and ultra-relativistic cases. The space charge impedance in the first case is discussed. For an impedance budget consideration of the electron machine only a simulation of the geometrical impedance in the latter case is necessary since space charge is considered separately.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB69

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2IO01

Specifics of Electron Dynamics in High Energy Circular e⁺e⁻ Colliders

ion, collider, sextupole, luminosity

1071

Q. Qin, J. Gao, H. Geng, P. He, D. Wang, N. Wang, Y. Wang, Y. Zhang
IHEP, Beijing, People's Republic of China

At the energies envisioned for the FCC-ee the synchrotron radiation produces not only closed orbit effects but also some dynamics effects including strong "beta-synchrotron" coupling due to radiation in the final focus quadrupoles. Past experience with LEP and other machines as well as the implications for the new wave of circular electron collider proposals will be discussed.

Slides THA2IO01 [6.536 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THA2IO01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA30

SCHARGEV 1.0 - Strong Space Charge Vlasov Solver

ion, space-charge, dipole, feedback

1164

T. Zolkin, A.V. Burov
Fermilab, Batavia, Illinois, USA

The space charge (SC) is known to be one of the major limitations for the collective transverse beam stability. When space charge is strong, i.e. SC tune shift much greater than synchrotron tune, the problem allows an exact analytical solution. For that practically important case we present a fast and effective Vlasov solver SCHARGEV (Space CHARGE Vlasov) which calculates a complete eigensystem (spatial shapes of modes and frequency spectra) and therefore provides the growth rates and the thresholds of instabilities. SCHARGEV 1.0 includes driving and detuning wake forces, and, any feedback system (damper). In the next version we will include coupled bunch interaction and Landau damping. Numerical examples for FermiLab Recycler and CERN SPS are presented.

Poster THPOA30 [1.493 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA30

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA33

A Preliminary Beam Impedance Model of the Advanced Light Source Upgrade at LBL

ion, cavity, vacuum, simulation

1174

S. Persichelli, J.M. Byrd, S. De Santis, D. Li, T.H. Luo, J.R. Osborn, C.A. Swenson, M. Venturini, Y. Yang
LBNL, Berkeley, California, USA

The proposed upgrade of the Advanced Light Source (ALS-U) consists of a multi-bend achromat ultralow emittance lattice optimized for the production of diffraction-limited soft x-rays. A narrow-aperture vacuum chamber is a key feature of the new generation of light sources, and can result in a significant increase in the beam impedance, potentially limiting the maximum achievable beam current. While the conceptual design of the vacuum system is still in a very early development stage, this paper presents a preliminary estimate of the beam impedance using a combination of electromagnetic simulations and analytical calculations. We include the impedance of cavities, select vacuum-chamber components and resistive wall in a multi-layered beam chamber with NEG coating.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA33

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA60

Status of PLSII Operation

ion, insertion, insertion-device, operation

1223

T.-Y. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

As the upgrade of PLS, PLSII is a 3 GeV light source in 12 super-periods (281.8 m circumference) with 5.8 nm design emittance and can store electron beam up to 400 mA with 3 superconducting RF cavities. Its most unique characteristic is that it has a short straight section and a long straight section for each cell (24 straight sections) and up to 20 insertion devices can be installed. But, as the installed insertion devices, particularly in-vacuum insertion devices, are sources of high impedance, these are quite challenging for high current operation. Current status of PLSII operation and future plans are described in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA60

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)