MC5: Beam Dynamics and EM Fields
D04: Beam Coupling Impedance - Theory, Simulations, Measurements, Code Developments

Paper	Title	Page
WEOZSP2	Suppression of Crab Cavity Noise Induced Emittance Growth by Transverse Beam Coupling Impedance	1659
SUSPMF068	use link to see paper's listing under its alternate paper code
	N. Triantafyllou, A. Wolski The University of Liverpool, Liverpool, United Kingdom F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou CERN, Meyrin, Switzerland T. Mastoridis CalPoly, San Luis Obispo, California, USA
	Crab Cav­i­ties are a key com­po­nent of the High Lu­mi­nos­ity LHC (HL-LHC) up­grade, as they aim to min­i­mize the lu­mi­nos­ity re­duc­tion caused by the cross­ing angle. Two su­per­con­duct­ing crab cav­i­ties were in­stalled in the Super Pro­ton Syn­chro­tron (SPS) at CERN in 2018 to test their op­er­a­tion in a pro­ton ma­chine for the first time. An im­por­tant point to con­sider is the in­crease in trans­verse emit­tance in­duced by noise in the Low-Level RF (LLRF) sys­tem. Dur­ing the first ex­per­i­men­tal cam­paign in 2018, the mea­sured emit­tance growth was found to be a fac­tor of 4 lower than pre­dicted by the avail­able an­a­lyt­i­cal mod­els. In this re­port, the ef­fects of trans­verse beam im­ped­ance in the pres­ence of CC LLRF noise on trans­verse emit­tance growth are pre­sented and the re­sults of the sec­ond ex­per­i­men­tal cam­paign, which took place in the SPS in 2021, are dis­cussed.
	Slides WEOZSP2 [2.694 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP2
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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WEOZSP3	Measurements of Radiation Fields From a Ceramic Break	1663
	Y. Shobuda, S. Hatakeyama, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan T. Toyama KEK, Tokai, Ibaraki, Japan
	Ce­ramic breaks are used in syn­chro­trons for many pur­poses. For ex­am­ple, they are in­serted be­tween the Multi-Wire Pro­file Mon­i­tor (MWPM) on the in­jec­tion line at the Rapid Cy­cling Syn­chro­tron (RCS) in J-PARC to com­pletely pre­vent the wall cur­rents ac­com­pa­ny­ing beams from af­fect­ing the MWPM. On the other hand, from the view­point of sup­press­ing beam im­ped­ances and the ra­di­a­tion fields from the ce­ramic breaks, it would be prefer­able that the inner sur­face of the ce­ramic break is coated with Ti­ta­nium Ni­tride (TiN), or cov­ered over ca­pac­i­tors. In this re­port, we mea­sure the ra­di­a­tion fields from the ce­ramic break with and with­out ca­pac­i­tors as well as the beam pro­file and in­ves­ti­gate the ef­fect of the ce­ramic breaks on the mea­sure­ments.
	Slides WEOZSP3 [35.441 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP3
About •	Received ※ 12 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 05 July 2022
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WEPOPT012	MAD-X for Future Accelerators	1858
	T.H.B. Persson, H. Burkhardt, R. De Maria, L. Deniau, E.J. Høydalsvik, A. Latina, P.K. Skowroński, R. Tomás García, L. van Riesen-Haupt CERN, Meyrin, Switzerland
	The de­vel­op­ment of MAD-X was started more than 20 years ago and it still re­mains the main tool for sin­gle par­ti­cle dy­nam­ics for both op­tics de­sign, error stud­ies as well as for op­er­a­tional model-based soft­ware at CERN. In this ar­ti­cle, we out­line some of the re­cent de­vel­op­ment of MAD-X and plans for the fu­ture. In par­tic­u­lar, we focus on the de­vel­op­ment of the twiss mod­ule used to cal­cu­late op­tics func­tions in MAD-X which is based on first and sec­ond order ma­tri­ces. These have tra­di­tion­ally been cal­cu­lated as an ex­pan­sion around the ideal orbit. In this paper, we de­scribe ex­plic­itly how an ex­pan­sion around the closed orbit can be em­ployed in­stead, in order to get more pre­cise re­sults. We also de­scribe the lat­est de­vel­op­ment of the beam-beam long range wire com­pen­sator in MAD-X, an el­e­ment that has been im­ple­mented using the afore­men­tioned ap­proach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT012
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 01 July 2022
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WEPOTK013	Direct Impedance Measurement of the CERN PS Booster Finemet Cavities	2064
	S.C.P. Albright, M.E. Angoletta, D. Barrientos, A. Findlay, M. Jaussi, J.C. Molendijk CERN, Meyrin, Switzerland
	Over CERN’s Long Shut­down 2, the con­ven­tional fer­rite-loaded cav­i­ties of the PS Booster were re­placed with wide-band Finemet-loaded cav­i­ties. The Finemet cav­i­ties bring many op­er­a­tional ad­van­tages, but also rep­re­sent a sig­nif­i­cant broad­band im­ped­ance source. The im­ped­ance is mit­i­gated by servo loops, which sup­press the in­duced volt­age, re­duc­ing the im­ped­ance as seen by the beam. Ac­cu­rately in­clud­ing the im­ped­ance of the cav­ity and the ef­fect of the ser­voloops in lon­gi­tu­di­nal track­ing sim­u­la­tions is es­sen­tial to pre­dict the per­for­mance with beam. This paper dis­cusses the re­sults of a mea­sure­ment cam­paign, which is in­tended to give a di­rect mea­sure­ment of the cav­ity im­ped­ance. Using the de­tected volt­age and the mea­sured beam pro­file, the cav­ity im­ped­ance can be in­ferred and used to im­prove beam dy­nam­ics mod­el­ling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK013
About •	Received ※ 26 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022
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WEPOTK037	Radiation of a Particle Moving Along a Helical Trajectory in a Resistive-Wall Cylindrical Waveguide	2150
	M. Ivanyan, A. Grigoryan, B. Grigoryan, B.K. Sargsyan CANDLE SRI, Yerevan, Armenia K. Flöttmann, F. Lemery DESY, Hamburg, Germany A. Grigoryan YSU, Yerevan, Armenia
	Funding: The work was supported by the Science Committee of RA, in the frames of the research project 21T-1C239 The ra­di­a­tion field of a par­ti­cle mov­ing on a he­li­cal tra­jec­tory in a cylin­dri­cal wave­guide with re­sis­tive walls is cal­cu­lated. The de­for­ma­tion of the en­ergy spec­trum of ra­di­a­tion, as a re­sult of the fi­nite con­duc­tiv­ity of the walls, is in­ves­ti­gated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK037
About •	Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
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WEPOTK039	Radiation of a Particle Moving Along a Helical Trajectory in a Semi-Infinite Cylindrical Waveguide	2154
	M. Ivanyan, A. Grigoryan, B. Grigoryan, V.G. Khachatryan, B.K. Sargsyan CANDLE SRI, Yerevan, Armenia K. Flöttmann, F. Lemery DESY, Hamburg, Germany A. Grigoryan YSU, Yerevan, Armenia
	Funding: The work was supported by the Science Committee of RA, in the frames of the research project 21T-1C239 The ra­di­a­tion field of a par­ti­cle which sud­denly ap­pears in an ideal wave­guide and moves on a he­li­cal tra­jec­tory under the in­flu­ence ofex­ter­nal mag­netic fields is cal­cu­lated. The shape and char­ac­ter of the front of the prop­a­gat­ing wave is de­ter­mined. The time de­pen­dence of ra­di­a­tion en­ergy ac­cu­mu­lated in the wave­guide is in­ves­ti­gated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK039
About •	Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 05 July 2022 — Issue date ※ 06 July 2022
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WEPOTK050	The Report of Machine Studies Related to the Vertical Beam Size Blow-Up in SuperKEKB LER	2169
	S. Terui, H. Fukuma, Y. Funakoshi, T. Ishibashi, T. Nakamura, K. Ohmi, Y. Ohnishi, M. Tobiyama, R. Ueki KEK, Ibaraki, Japan
	In the Low En­ergy Ring (LER) for positrons in the Su­perKEKB, a ver­ti­cal beam size blow-up was ob­served when the bunch cur­rent was ap­prox­i­mately 1 mA. If a beam size blow-up oc­curs, the de­sign lu­mi­nos­ity can­not be achieved. There­fore, beam size blow-ups must be pre-vented. Ac­cord­ing to cal­cu­la­tions, the bunch cur­rent thresh­old of the Trans­verse Mode Cou­pling in­sta­bil­ity (TMCI) is 2 mA or more, and the ob­served value is 50% or smaller. This ver­ti­cal beam size blow-up can­not be ex­plained by or­di­nary TMCI. This paper shows that by an­a­lyz­ing fac­tors such as beam os­cil­la­tion, the cause of the ver­ti­cal beam size blow-up was de­ter­mined. The study re­sults showed that the ver­ti­cal beam size blow-up in the LER was caused by the os­cil­la­tions of the -1 mode.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK050
About •	Received ※ 17 May 2022 — Accepted ※ 22 June 2022 — Issue date ※ 25 June 2022
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WEPOTK051	Beam Induced Power Loss Estimation of a Movable Synchrotron Light Extraction Mirror for the LHC	2173
	M. Wendt, W. Andreazza, E. Bravin, F. Guillot-Vignot CERN, Meyrin, Switzerland
	Beam in­stru­ments based on syn­chro­tron light are an im­por­tant part of the beam mon­i­tor­ing di­ag­nos­tics suite in the Large Hadron Col­lider (LHC) at CERN. In frame of the high lu­mi­nos­ity up­grade (HL-LHC) ad­di­tional syn­chro­tron light di­ag­nos­tics are de­manded, too many to be cov­ered by the pre­sent Beam Syn­chro­tron-light Ra­di­a­tion Tele­scope (BSRT), which uti­lizes a fixed light ex­trac­tion mir­ror. There­fore, an ad­di­tional syn­chro­tron light di­ag­nos­tics setup is under de­vel­op­ment, now with a mov­able mir­ror to ex­tract the syn­chro­tron light emit­ted solely by a su­per­con­duct­ing LHC di­pole mag­net. With higher bunch in­ten­si­ties an­tic­i­pated in the HL-LHC, the beam in­duced power losses, and there­fore local heat dis­si­pa­tion, play a crit­i­cal role in the de­sign of the ex­trac­tion mir­ror. This paper sum­ma­rizes the es­ti­ma­tion of the bunched-beam in­duced power losses based on nu­mer­i­cal sim­u­la­tions and RF mea­sure­ments on a pro­to­type light ex­trac­tion mir­ror.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK051
About •	Received ※ 06 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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WEPOTK052	Beam Coupling Impedance Study and Its Database of Siam Photon Source Storage Ring	2177
	N. Juntong, T. Chanwattana, S. Jummunt, K. Kittimanapun, T. Phimsen, W. Promdee, T. Pulampong SLRI, Nakhon Ratchasima, Thailand
	Since the Siam Pho­ton Source (SPS) had an elec­tron beam en­ergy up­graded from 1.0 GeV to 1.2 GeV in 2005, the stor­age ring im­ped­ance mea­sure­ments were done once in 2007. Two in­ser­tion mag­net de­vices have been in­stalled in the SPS stor­age ring dur­ing June to Au­gust 2013. There are sev­eral vac­uum com­po­nents added to the stor­age ring; these af­fect the ring im­ped­ance. Quan­ti­ta­tive un­der­stand­ing of in­sta­bil­i­ties re­quires de­tailed knowl­edge of the im­ped­ance of the ring. For this pur­pose, the de­vel­op­ment of an im­ped­ance data­base is a ne­ces­sity, where the wake po­ten­tials of each vac­uum com­po­nent are kept and main­tained in a stan­dard for­mat. The self-de­scrib­ing data sets (SDDS) file for­mat will be uti­lized to record com­po­nents wake po­ten­tials. The wake po­ten­tials of each vac­uum com­po­nent can be ob­tained from a par­ti­cle track­ing sim­u­la­tion; a CST par­ti­cle stu­dio pro­gram will be used in the sim­u­la­tion process. The wake po­ten­tials can also be in­cluded in a beam dy­namic track­ing pro­gram such as EL­E­GANT to ob­serve beam be­hav­iors with these in­sta­bil­i­ties and find a cur­ing means. The study re­sults will be pre­sented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK052
About •	Received ※ 19 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 25 June 2022
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WEPOTK053	Simulation of Bunch Formation for the Mu2e Experiment	2180
	K.P. Harrig, E. Prebys UCD, Davis, California, USA V.P. Nagaslaev, S.J. Werkema Fermilab, Batavia, Illinois, USA
	Funding: Grant DE-SC0019254, The U.S. Department of Energy, Office of Science and Fermi Research Alliance, LLC Contract No. DE-AC02-07CH11359 The Fer­mi­lab Re­cy­cler is an 8 GeV stor­age ring com­posed of per­ma­nent mag­nets that was cru­cial to the suc­cess of the Fer­mi­lab Teva­tron Col­lider pro­gram. It is cur­rently being used to slip-stack pro­tons for the high en­ergy neu­trino pro­gram and to re-bunch pro­tons for use in the Muon g-2 and Mu2e ex­per­i­ments. For the lat­ter ap­pli­ca­tions, the Re­cy­cler re-bunches each 1.6 µs "batch" from the Fer­mi­lab Booster into four 2.5 MHz bunches. For the Mu2e ex­per­i­ment, it is cru­cial that beam more than 125 ns from the nom­i­nal bunch cen­ter be sup­pressed by at least a fac­tor of 1E-5. While bunch for­ma­tion is cur­rently in op­er­a­tion for the g-2 ex­per­i­ment, this out of time re­quire­ment has not been met, and the rea­son is not un­der­stood. This work pre­sents a sim­u­la­tion of bunch for­ma­tion in the Re­cy­cler, in an ef­fort to un­der­stand the rea­son for this ex­ces­sive out of time beam and to search for a way to re­duce it.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK053
About •	Received ※ 30 May 2022 — Revised ※ 16 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 11 July 2022
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WEPOTK059	Suppression of Emittance Growth by a Collective Force: Van Kampen Approach	2197
	X. Buffat CERN, Meyrin, Switzerland
	In hadron syn­chro­trons, ex­ter­nal sources of noise af­fect­ing the beam in­duce emit­tance growth through the mech­a­nism of de­co­her­ence. Ac­tive feed­backs are often used to sup­press this emit­tance growth. In the pres­ence of beam-beam in­ter­ac­tions, it was shown that co­her­ent modes of os­cil­la­tions with fre­quen­cies shifted out­side of the in­co­her­ent spec­trum sig­nif­i­cantly en­hances the ef­fi­ciency of the emit­tance growth sup­pres­sion by ac­tive feed­backs. We show that the same en­hance­ment of the emit­tance growth sup­pres­sion may be dri­ven by a beam cou­pling im­ped­ance gen­er­at­ing a real tune shift larger than the de­tun­ing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK059
About •	Received ※ 03 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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WEPOTK063	A Wireless Method to Obtain the Impedance From Scattering Parameters	2213
	C. Antuono, M. Migliorati, E. Métral, C. Zannini CERN, Meyrin, Switzerland M. Migliorati, A. Mostacci LNF-INFN, Frascati, Italy A. Mostacci Sapienza University of Rome, Rome, Italy
	The coax­ial wire method is a com­mon and ap­pre­ci­ated choice to as­sess the beam cou­pling im­ped­ance of an ac­cel­er­a­tor el­e­ment from scat­ter­ing pa­ra­me­ters. Nev­er­the­less, the re­sults ob­tained from wire mea­sure­ments could be in­ac­cu­rate due to the pres­ence of the stretched con­duc­tive wire that ar­ti­fi­cially cre­ates the con­di­tions for the prop­a­ga­tion of a Trans­verse Elec­tro­Mag­netic (TEM) mode. The aim of this work is to es­tab­lish a solid tech­nique to ob­tain the beam cou­pling im­ped­ance from elec­tro­mag­netic sim­u­la­tions, with­out mod­i­fi­ca­tions of the de­vice under test. In this frame­work, we iden­ti­fied a new re­la­tion to get the re­sis­tive wall beam cou­pling im­ped­ance of a cir­cu­lar cham­ber di­rectly from the scat­ter­ing pa­ra­me­ters and demon­strated that it re­duces to the exact the­o­ret­i­cal ex­pres­sion. Fur­ther­more, a pos­si­ble gen­er­al­iza­tion of the method to ar­bi­trary cross sec­tion geome­tries has been stud­ied and val­i­dated with nu­mer­i­cal sim­u­la­tions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK063
About •	Received ※ 07 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 20 June 2022
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WEPOMS004	Investigation of RF Heating for the Multipole Injection Kicker Installed at SOLEIL	2233
	A. Gamelin, P. Alexandre, R. Ben El Fekih, J. Da Silva Castro, M. El Ajjouri, A. Letresor, L.S. Nadolski, R. Ollier, T.S. Thoraud SOLEIL, Gif-sur-Yvette, France M. Sacko, S. Taurines Avantis Concept, SAINT-CERE, France
	Dur­ing the com­mis­sion­ing of the new Mul­ti­pole In­jec­tion Kicker (MIK) pulsed mag­net at SOLEIL syn­chro­tron, an anom­alously high heat­ing of the MIK cham­ber and flanges was found. To bet­ter man­age the heat load, fans di­rected to­ward the MIK were added to im­prove the air-cool­ing flow. This al­lowed the nom­i­nal cur­rent to be reached in all op­er­a­tion modes while keep­ing rea­son­able tem­per­a­tures on the MIK. Post-in­stal­la­tion in­ves­ti­ga­tions sub­se­quently showed that the ini­tial es­ti­mate of the max­i­mal heat load was in agree­ment with the mea­sured tem­per­a­ture in sev­eral op­er­a­tion modes both with and with­out the ad­di­tional fans. In this ar­ti­cle, we pre­sent the com­plete study, start­ing from the im­ped­ance cal­cu­la­tion to ther­mal sim­u­la­tions, and com­par­i­son with the mea­sured data with beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS004
About •	Received ※ 18 May 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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WEPOMS006	Simulation of the Effect of Corrugated Structures on the Longitudinal Beam Dynamics at KARA	2241
	S. Maier, M. Brosi, A. Mochihashi, A.-S. Müller, M.J. Nasse, P. Schreiber, M. Schwarz KIT, Karlsruhe, Germany
	Funding: Supported by the DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC. S. M. acknowledge the support by the Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology" (KSETA). Two par­al­lel cor­ru­gated plates will be in­stalled at the KIT stor­age ring KARA (KArl­sruhe Re­search Ac­cel­er­a­tor). This im­ped­ance ma­nip­u­la­tion struc­ture will be used to study and even­tu­ally con­trol the beam dy­nam­ics and the emit­ted co­her­ent syn­chro­tron ra­di­a­tion (CSR). In this con­tri­bu­tion, we pre­sent the re­sults ob­tained with the Vlasov-Fokker-Planck solver In­ovesa show­ing the im­ped­ance im­pact of dif­fer­ent cor­ru­gated struc­tures on the bunch and its emit­ted CSR power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS006
About •	Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 02 July 2022
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