IPAC2019 - List of Keywords (cryogenics)

Paper	Title	Other Keywords	Page
MOPRB065	Enhancing Experimental Prospects With Low Energy Antiprotons	proton, antiproton, detector, experiment	727
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkłodowskaCurie grant agreement No 721559. The Extra Low Energy Antiproton ring (ELENA) is a critical upgrade to the Antiproton Decelerator (AD) at CERN and saw the first beam in 2018. ELENA will significantly enhance the achievable quality of low energy antiproton beams and enable new experiments. To fully exploit the potential of this new facility, advances are required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to fully characterize the beam’s properties, as well as in novel experiments that take advantage of the enhanced beam quality that ELENA can provide. These research areas are in the heart of the pan-European research and training network AVA (Accelerators Validating Antimatter physics) which started in 2017. This contribution presents research results within AVA on the performance of ultra-thin diamond membranes, electron cooling and beam life time studies of low energy ion and antiproton beams, as well as efficient integration and performance optimization of cryogenic detectors in ELENA and associated trap experiments. These results are used to describe the optimum layout of a state-of-the-art low energy antiproton facility and associated experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB065
About •	paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPTS007	SARAF Equipped Cavity Test Stand (ECTS) at CEA	cavity, cryomodule, controls, EPICS	852
	O. Piquet, C. Boulch, D. Chirpaz-Cerbat, G. Ferrand, F. Gohier, T.J. Joannem, G. Monnereau, Th. Plaisant CEA-IRFU, Gif-sur-Yvette, France D. Braud, P. Carbonnier, P. Guiho, L. Maurice, J. Plouin, P. Sahuquet, N. Solenne CEA-DRF-IRFU, France F. Gouit, A. Pérolat CEA, Gif-sur-Yvette, France
	CEA is committed to delivering a Medium Energy Beam Transfer line and a Super Conducting Linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3MeV to 35MeV or deuterons from 2.6 MeV to 40.1MeV. The SCL consists in 4 cryomodules separated by warm section housing beam diagnostics. The two first identical cryomodules hosts respectively 6 and 7 half-wave resonator (HWR) low beta (0.091) cavities 176MHz. In order to test the cavity with its tuner and coupler and validate some design consideration, the Equipped Cavity Test Stand (ECTS) has been designed and will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS007
About •	paper received ※ 07 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS052	Simulation of Electric and Thermal Behavior of Cryogenic Three-cell Copper Accelerating Cavity for High Gradient Experiments	cavity, simulation, coupling, experiment	980
	T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, Y. Takahashi LEBRA, Funabashi, Japan
	A C-band three-cell pi-mode accelerating cavity made of high purity copper is under design for use in ultra-high accelerating gradient experiments at a cavity temperature of 20 K. The basic configuration, consisting of mode converter, short circular waveguide and cells with round periphery, is the same as that which was previously employed in the cold model for a 2.6-cell photocathode electron gun cavity. Though the 0.6-cell part in the previous model is replaced with a full cell having a beam duct, the overall electric property of the cavity will not change significantly. The RF input coupling coefficient is adjusted to around 10 at 20 K, which is expected to be lowered significantly due to the increase in the surface resistance by the rapid temperature rise during a high power RF input. The results of the simulations on the electric field and the temperature rise along the cavity surface during the RF pulse are discussed in the report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS052
About •	paper received ※ 13 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPTS117	Exploration of High-Gradient Structures for 4th Generation Light Sources	cavity, FEL, linac, electron	1155
	S.J. Smith, S. Biedron, S.I. Sosa Guitron University of New Mexico, Albuquerque, USA T.B. Bolin Element Aero, Chicago, USA B.E. Carlsten, F.L. Krawczyk LANL, Los Alamos, New Mexico, USA J.R. Cary, D.M. Cheatham Tech-X, Boulder, Colorado, USA
	As the energy, scale and therefore the cost of large-scale accelerator projects, such as X-ray free-electron lasers (XFELs) increases, new technologies must be developed in order to minimize costs and maximize efficiency wherever possible. One obvious way to reduce costs is to reduce the length of accelerating sections by utilizing higher accelerating gradients. Here we present the results of a study into the various structure options for FEL linacs, contrasting different frequencies, geometries and operating modes. An investigation into the possibility of using cryo-cooled travelling wave (TW) electron structures which allow for higher gradient operation by exploiting the anomalous skin effect is also detailed. Finally, we give simulation results from a number of commercial codes including VSim 9, for a hypothetical TW high gradient C-band structure design employing cryo-cooled technology. Breakdown effects, pulsed heating, tolerances, efficiencies and potential rf sources are also explored, all within the framework of typical FELs and their requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS117
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPMP006	Cryogenic Tests of the SPIRAL2 LINAC Systems	cavity, cryomodule, linac, operation	1240
	A. Ghribi, P.-E. Bernaudin, R. Ferdinand, A.V. Vassal GANIL, Caen, France
	Two full cool-down of the SPIRAL2 superconducting LINAC have been performed in 2017 and 2018 respectively, followed by a total of around 5 months of tests at 4 K. Several cool-down strategies were tested, in order to minimize 100 K effect on the SC cavities. Helium bath regulations (level and pressure) have been tested and optimized. Effects of pressure instabilities and coupling with the cryogenic plant have also been observed. Cryogenic performances of each cryomodule have been measured. Low-level RF measurements were also performed on all cavities and showed unidentified modulations at frequencies around 5Hz. These turned out to be thermoacoustic oscillations (TAO) on the cryogenic lines, which generate important pressure instabilities. Several solutions to remove TAO and cure these instabilities have been tested and one has been successfully deployed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP006
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPMP045	The Protection Instrument for Cryogenic Phase Separator Pressure Relief Valve of TPS Beamline	controls, monitoring, software, operation	1350
	C.C. Liang, C.Y. Chang, C.F. Chang, Y.H. Guo, M.H. Lee, C.Y.L. Liu, T.-C. Yu NSRRC, Hsinchu, Taiwan
	TPS (Taiwan Photon Source) beamlines have operated for three years after the successful commission in 2015. Recently, the electromagnetic activated pressure relief valve of cryogenic phase separator of beamline had malfunction due to the rust of its control circuits. After on site observation and temperature records, the water was found to be condensed around the outlet area due to fast temperature dropping near the valve as it was activated. Such situation would cause the rust of metal components due to humidity after a certain period of time. To avoid such event, fan is used to blow the condensed water and silicone heat belts are added to increase the local temperature with unique designed clamp for fixing the fan, sensors and safety circuit breaker. Via the temperature control system, the temperature monitoring, setting and the abnormal situation can be access on web page through Ethernet to make sure the proper operation of the protected devices. The instrument has been operated since Dec. 2018. After four months of operation, the moist situation has been improved and the relief valve is no longer frosted.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP045
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP047	Upgrade of the Cryogenic Control System for SRF Modules at the Taiwan Light Source	controls, SRF, operation, interface	1356
	F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, S.W. Chang, L.J. Chen, Y.T. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	An upgrade of the cryogenic control system for superconducting radio-frequency (SRF) modules of the Taiwan Light Source (TLS) has been completed. The biggest challenge was to recover all protection and operational functions, while minimizing the quantity of vented helium from SRF modules while replacing valve controllers. Gradually, this work was finished within several one- and ten-day scheduled machine shutdown periods for accelerator maintenance. No large helium vent nor pollution of the cryogenic system occurred during all component replacements and function verifications. Functions of the cryogenic electronics were improved, whereas the valve controllers are upgraded to new versions to increase reliability and availability. Communications with the data acquisition system was also secured by buffered signal processing module so that device shutdown of the data acquisition system will not interrupt the cryogenic valve operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP047
About •	paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP054	Investigations on Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18	vacuum, heavy-ion, synchrotron, operation	1372
	L.H.J. Bozyk, S. Aumüller, P.J. Spiller GSI, Darmstadt, Germany
	The heavy ion synchrotron SIS18 at GSI will serve as injector ring for the FAIR-facility and provide high intensity heavy ion beams. The operation of such beams requires the usage of low charge states, which have high cross sections for ionization. To overcome this issue, many upgrade measure have been realized in the past decade, such as the installation of an ion catcher system with low desorption surfaces and coating 65% of the circumference of SIS18 with NEG to lower the static gas pressure. Since the vacuum dynamics during operation prevent the achievement of the intensity goals for FAIR, new concepts have to be developed, to increase the beam intensity. One idea is the installation of additional pumping speed in the form of cryogenic surfaces. Heavy residual gas components, which have the highest ionization cross sections can be cryopumped at moderate temperatures, i.e. already at 50-80 K. In fact, the only typical residual gas component which can not be pumped via cryosorption in this temperature regime is Hydrogen, which has a factor 50 lower ionization cross sections than Argon, the heaviest residual gas component. In this paper, we present a study of the integration of cryopanels into the vacuum chambers of SIS18.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP054
About •	paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPTS006	Tests at High RF Power of the ESS Medium Beta Cryomodule Demonstrator	cavity, cryomodule, linac, status	1940
	P. Bosland, C. Arcambal, F. Ardellier, S. Berry, A. Bouygues, E. Cenni, G. Devanz, T. Hamelin, X. Hanus, O. Piquet, J.P. Poupeau, B. Renard, P. Sahuquet CEA-DRF-IRFU, France C. Darve ESS, Lund, Sweden P. Michelato INFN/LASA, Segrate (MI), Italy G. Olivier, J.P. Thermeau IPN, Orsay, France
	CEA is in charge of the 30 elliptical medium and high-beta cryomodules to be installed in the ESS tunnel in Lund, Sweden. Before launching the assembly of the series cryomodules, CEA developed a medium-beta cryomodule technology demonstrator in a collaboration with IPNO, LASA and ESS. This paper briefly presents the cryomodule assembly and summarizes the main results of the high RF power tests performed in 2018 in a dedicated test stand in CEA Saclay. The main ESS requirements were reached: E_acc = 16.7 MV/m in cavities, Pforward = 1.1 MW in power couplers, RF pulses length = 3.6 ms at 14 Hz. The piezo tuners efficiently compensated the Lorentz forces detuning and could stabilize the accelerating field better than 1% over the full length of the expected ESS 2.86 ms beam pulse without any LLRF regulation system. Following this successful validation CEA started the assembly of the first ESS medium-beta series cryomodule
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS006
About •	paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPTS114	Electron Stimulated Desorption from Cryogenic NEG-Coated Surfaces	vacuum, electron, experiment, site	2193
	R. Sirvinskaite, M.D. Cropper Loughborough University, Loughborough, Leicestershire, United Kingdom A.N. Hannah, O.B. Malyshev, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Non-Evaporable Getter (NEG) coating has been used for years in many particle accelerators due to its advantages like evenly distributed pumping speed, low thermal outgassing, and low photon, electron and ion stimulated desorption yields. Although NEG coating has been tested at room temperatures intensively, there is little data on its behaviour at cryogenic temperatures. Tests in this environment are important for the Future Circular Collider (FCC) study and other accelerator facilities where the operational conditions of the beam screen are restricted to cryogenic temperatures. This work will provide some preliminary results on NEG properties at low temperatures, e.g. pumping speed and capacity, as well as its behaviour under electron bombardment, where electron stimulated desorption (ESD) yields will be calculated. The ternary Ti-Zr-V coating, deposited with dense and columnar structure, will be the first material to be tested at cryogenic temperatures in ASTeC Daresbury laboratory. The results were compared with the ones obtained at room temperature, offering an insight into the behaviour of NEG-coated cryogenic chambers when beam-induced effects are present.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS114
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPGW020	Next Generation Cryogenic Current Comparator (CCC) for nA Intensity Measurement	shielding, pick-up, coupling, detector	2510
	T. Sieber, D.M. Haider, H. Reeg, M. Schwickert, T. Stöhlker GSI, Darmstadt, Germany H. De Gersem, N. Marsic, W.F.O. Müller TEMF, TU Darmstadt, Darmstadt, Germany J. Golm, F. Schmidl, P. Seidel, V. Tympel FSU Jena, Jena, Germany M. Schmelz, R. Stolz, V. Zakosarenko IPHT, Jena, Germany T. Stöhlker IOQ, Jena, Germany T. Stöhlker HIJ, Jena, Germany J. Tan, G. Tranquille CERN, Geneva, Switzerland
	A Cryogenic Current Comparator (CCC) is an extremely sensitive DC-Beam Transformer based on superconducting SQUID technology. Recently, a CCC without a toroidal core and with an axially oriented magnetic shielding has been developed at the Institute of Photonic Technologies (IPHT) Jena/Germany. It represents a compact and lightweight alternative to the ’classical’ CCC, which was originally developed at PTB Braunschweig and is successfully in operation in accelerators at GSI and CERN. Excellent low-frequency noise performance was demonstrated with a prototype of this new CCC-type. Current measurements and further tests are ongoing, first results are presented together with simulation calculations for the magnetic shielding. The construction from lead as well as simplified manufacturing results in drastically reduced costs compared to formerly used Nb-CCCs. Reduced weight also puts less constraints on the cryostat. Based on highly sensitive SQUIDs, the new prototype device shows a current sensitivity of about 6 pA/Hz1/2 in the white noise region. The measured and calculated shielding factor is ~135 dB. These values, together with a significant cost reduction - resulting also from a compact cryostat design - opens up the way for widespread use of CCCs in modern accelerator facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW020
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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WEPRB025	High Density Mapping for Superconducting Cavities	cavity, radiation, status, operation	2860
	Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan Y. Fuwa Kyoto University, Research Reactor Institute, Osaka, Japan R.L. Geng JLab, Newport News, Virginia, USA H. Hayano KEK, Ibaraki, Japan
	High density mapping system for superconducting cavities are under development. Testing on the stiffener X-ray mapping system at JLAB showed consistent results in comparison with simultaneously taken GM tube or ion chamber output signals. The system provides better visi-bility as shown by data briefly reported here. In addition to the temperature and the X-ray mapping, a sensitive magnetic field mapping system with high spatial density is also under development. The magnetic field sensor is AF755B, whose operations at cryogenic temperatures are already reported by other group. Our development status using the magnetic field sensor will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB025
About •	paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPRB098	Cryogenic RF Performance of Double-Quarter Wave Cavities Equipped with HOM Filters	cavity, HOM, operation, SRF	3043
	S. Verdú-Andrés, I. Ben-Zvi, Q. Wu, B.P. Xiao BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom G. Burt, J.A. Mitchell Lancaster University, Lancaster, United Kingdom R. Calaga, O. Capatina CERN, Geneva, Switzerland N.A. Huque, E.A. McEwen, H. Park, T. Powers JLab, Newport News, Virginia, USA Z. Li, A. Ratti SLAC, Menlo Park, California, USA
	Funding: Work supported by US DOE through BSA LLC under contracts No. DE-AC02-98CH10886, No. DE-SC0012704, and the US LHC Accelerator Research Program (LARP) and by the EU HL-LHC Project. Crab cavities are one of the several components included in the luminosity upgrade of the Large Hadron Collider (HL-LHC). The cavities have to provide a nominal deflecting kick of 3.4 MV per cavity while the cryogenic load per cavity stays below 5 W. Cold RF tests confirmed the required performances in bare cavities, with several cavities exceeding the required voltage by more than 50%. However, the first tests of a Double-Quarter Wave (DQW) cavity with one out of three HOM filters did not reach the required voltage. The present paper describes the studies and tests conducted on a DQW cavity with HOM filter to understand the limiting factor. The recipe to meet the performance specification and exceed the voltage requirement by more than 35% is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB098
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THYYPLS2	Different Versions of Cryogenic Current Comparators with Magnetic Core for Beam Current Measurements	shielding, pick-up, operation, proton	3431
	J. Golm, F. Schmidl, P. Seidel FSU Jena, Jena, Germany H. De Gersem, N. Marsic, W.F.O. Müller TEMF, TU Darmstadt, Darmstadt, Germany M.F. Fernandes, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom M.F. Fernandes, J. Tan, C.P. Welsch CERN, Geneva, Switzerland M.F. Fernandes, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom D.M. Haider, F. Kurian, M. Schwickert, T. Sieber, T. Stöhlker GSI, Darmstadt, Germany R. Neubert Thuringia Observatory Tautenburg, Tautenburg, Germany M. Schmelz, R. Stolz, V. Zakosarenko IPHT, Jena, Germany T. Stöhlker IOQ, Jena, Germany T. Stöhlker, V. Tympel HIJ, Jena, Germany V. Zakosarenko Supracon AG, Jena, Germany
	For more than 20 years Cryogenic Current Comparators (CCC) are used to measure the current of charged particle beams with low intensity (nA-range). The device was first established at GSI in Darmstadt and was improved over the past two decades by the cooperation of institutes in Jena, GSI and CERN. The improved versions differ in material parameters and electronics to increase the resolution and in dimensions in order to meet the requirements of the respective application. The device allows non-destructive measurements of the charged particle beam current. The azimuthal magnetic field which is generated by the beam current is detected by low temperature Superconducting Quantum Interference Device (SQUID) current sensors. A complex shaped superconductor cooled down to 4.2 K is used as magnetic shielding and a high permeability core serves as flux concentrator. Three versions of the CCC shall be presented in this work: (1) GSI-Pb-CCC which was running at GSI Darmstadt in a transfer line, (2) CERN-Nb-CCC currently installed in the Antiproton Decelerator at CERN and (3) GSI-Nb-CCC-XD which will be operating in the CRYRING at GSI 2019. Noise, signal and drift measurements were performed in the Cryo-Detector Lab at the University of Jena.
	Slides THYYPLS2 [4.344 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THYYPLS2
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS001	Development of Cryogenic Suspension in the ANU 8t Superconducting Solenoid With Iron Yoke	solenoid, vacuum, experiment, EPICS	4103
	S.T. Battisson, N.R. Lobanov, D. Tsifakis, T.B. Tunningley Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia J.F. Smith University of Surrey, Department of Physics, Guildford, United Kingdom
	Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism. An 8 Tesla superconducting solenoid was commissioned at The Australian National University to make precision measurements of fusion cross-sections. Forces between the solenoid and the iron yoke that houses it must always be maintained within safe limits and precision location of the solenoid coil is necessary to achieve this. Thermal contraction of components can impact the locating structure of the solenoid coil, leading to unsafe forces. Improvements to this structure allowed successful completion of the first fusion measurements with the 8T solenoidal separator, and demonstrated that it is now ready for a program of fusion measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS001
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS011	Design, Production, and Testing of Superconducting Magnets for the Super-FRS	dipole, quadrupole, octupole, superconducting-magnet	4128
	H. Müller, E.J. Cho, G. Golluccio, C. Roux, H. Simon, K. Sugita, M. Winkler GSI, Darmstadt, Germany H. Allain, M. Daly, P. Grafin, A. Madur, J.-E. Munoz-Garcia, L. Quettier, H. Reymond CEA-IRFU, Gif-sur-Yvette, France A. Borceto, G. Drago, G. Valesi, D. Ventura ASG, Genova, Italy J. Lucas Elytt Energy, Madrid, Spain L.X. Van Den Boogaard CERN, Geneva, Switzerland
	The Super FRS is a two-stage in flight separator to be built next to the site of GSI, Darmstadt, Germany as part of FAIR (Facility for Anti-proton and Ion Research). Its purpose is to create and separate rare isotope beams and to enable the mass measurement also for very short lived nuclei. Due to its three branches a wide variety of experiments can be carried out in frame of the NUSTAR collaboration. Due to the large acceptance needed, the magnets of the Super-FRS have to have a large aperture and therefore only a superconducting solution is feasible. A superferric design with superconducting coils was chosen in which the magnetic field is shaped by an iron yoke. For the dipoles this iron yoke is at warm and only the coils are incorporated in a cryostat. The multiplets, assemblies of quadrupoles and higher order multipole magnets, are completely immersed in a liquid Helium bath. With the exception of special branching dipoles all superconducting magnets of Super-FRS have been contracted and are being built by Elytt in Spain (dipoles) and ASG in Italy (multiplets). The cold test of all magnets will take place in a dedicated test facility at CERN. This contribution will present the status of manufacturing of dipoles and multiplets, and also gives a short overview on the test facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS011
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS029	Optimization of Staggered Array Undulator	undulator, solenoid, electron, site	4171
	L.J. Chen, Q.K. Jia USTC/NSRL, Hefei, Anhui, People’s Republic of China M. Li, P. Li, J. Wang, D. Wu, D.X. Xiao, L.G. Yan, X. Yang CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
	Funding: the National Key Research and Development Program of China under Grant No. 2016YFA0402003 the National Nature Science Foundation of China under Grant No. 11611140102. The staggered array undulator consists of staggered poles and solenoid coils that form a periodically aligned transverse magnetic field in the pole gap. The addition of magnets in the longitudinal gap between the poles further enhances the peak field strength of the undulator. A method of enhancing the peak field strength of the undulator using cryogenic temperature permanent magnets and adding side magnets has been studied. The remanence of the magnet will increase at low temperatures and the peak field strength of the undulator will increase. The side magnets do not increase the maximum peak field strength of the undulator, but can reduce the solenoid magnetic field requirements and reduce the solenoid volume and cost. The influence of the special magnetic pole and magnet shape on the peak field strength of the undulator has also been studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS029
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS066	Beam Impact Experiment of 440GeV/p Protons on Superconducting Wires and Tapes in a Cryogenic Environment	experiment, proton, interface, simulation	4264
	A. Will, A. Bernhard, A.-S. Müller KIT, Karlsruhe, Germany Y. Bastian, B. Bordini, M. Favre, B. Lindstrom, M. Mentink, A. Monteuuis, A. Oslandsbotn, R. Schmidt, A.P. Siemko, K. Stachon, M.P. Vaananen, A.P. Verweij, A. Will, D. Wollmann CERN, Geneva, Switzerland M. Bonura, C. Senatore UNIGE, Geneva, Switzerland A. Usoskin BRUKER HTS GmbH, Alzenau, Germany
	The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failure cases. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, directly or via secondary particle showers. The interaction leads to energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb₃Sn strands as well as YBCO tape in a cryogenic environment to microsecond 440 GeV/p proton beams. The irradiated samples were extracted and are being analyzed for their superconducting properties, such as the critical transport current. This paper describes the experimental setup as well as the first results of the visual inspection of the samples.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS066
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPTS071	Performance of TPS Cryogenic Permanent Magnet Undulators at NSRRC	undulator, vacuum, permanent-magnet, controls	4278
	J.C. Huang, C.S. Yang, C.K. Yang NSRRC, Hsinchu, Taiwan H. Kitamura RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan T. Kohda NEOMAX Engineering Co., Ltd., Tokyo, Japan
	Development of cryogenic permanent magnet un-dulators (CPMUs) is the most recent activity for Phase-II beamlines at the Taiwan Photon Source. A hybrid-type CPMU with a period length of 15 mm, based on PrFeB permanent-magnet materials, is under construc-tion. A maximum effective magnetic field of 1.33 T at a gap of 4 mm is obtained at 80 K.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS071
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS080	Novel Technique Ion Assisted In-Situ Coating of Long, Small Diameter, Accelerator Beam Pipes with Compacted Thick Crystalline Copper Film	cathode, lattice, vacuum, plasma	4301
	A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, G.T. McIntyre, S. Verdú-Andrés BNL, Upton, Long Island, New York, USA A.X. Custer, M.Y. Erickson, H.J. Poole PVI, Oxnard, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy Although great progress was made with in-situ copper coating, by magnetron sputtering, to address the high room temperature resistivity, literature indicates that conventionally deposited thick copper films do not retain the same RF conductivity at cryogenic temperatures, since straightforward deposition tends to result in films with columnar structure and other lattice defects, which cause significant conductivity degradation at cryogenic temperatures. We utilize energetic ions for ion assisted deposition (IAD) to reduce lattice imperfections, for coating. IAD that can in-situ coat long small diameter tubes with compacted crystalline structure thick copper films has been developed. Moreover, development of techniques and devices can resurrect IAD for other applications, which have been impractical and/or not viable economically. Comparison of conductivity at cryogenic temperatures between straight magnetron physical vapor deposition and IAD will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS080
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS081	Novel Apparatus and Technique for Measuring RR Resistivity of Tube Coatings at Cryogenic Temperatures	lattice, cavity, experiment, vacuum	4304
	A. Hershcovitch, J.M. Brennan, R. Than, S. Verdú-Andrés, Q. Wu BNL, Upton, Long Island, New York, USA A.X. Custer, M.Y. Erickson, H.J. Poole PVI, Oxnard, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy A unique apparatus for measuring RF resistivity of tubes and coated tubes at cryogenic temperatures is operational at BNL, which to our knowledge is the first of its kind. A folded quarter wave resonator structure of 300 mm length accesses a wide range of frequencies. The structure is cooled in liquid He bath at 4 K. All internal resonator components (except for test samples) were fabricated out of superconducting materials. Consequently, when the resonator is cooled, the bulk of the losses are due to the copper coating. The RF resistivity is determined from Q measurements, since for a fixed geometry the quality factor of a resonant cavity is proportional to the square root of the conductivity. The RF input loop and the output signal antenna are adjustable when cold via bellows to control matching to each cavity mode. The Q values of 10 resonant modes between 180 and 2500 MHz are deduced from the bandwidth of the S21 response Network Analyzer measurements. CST MicroWave Studio is used to extract the resistivity of the samples from the Q measurements. Resistivity results of solid Cu tube, 2, 5, & 10 μm Cu coated 316LN stainless steel RHIC beam tubes will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS081
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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Paper

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MOPRB065

Enhancing Experimental Prospects With Low Energy Antiprotons

proton, antiproton, detector, experiment

727

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkłodowskaCurie grant agreement No 721559.
The Extra Low Energy Antiproton ring (ELENA) is a critical upgrade to the Antiproton Decelerator (AD) at CERN and saw the first beam in 2018. ELENA will significantly enhance the achievable quality of low energy antiproton beams and enable new experiments. To fully exploit the potential of this new facility, advances are required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to fully characterize the beam’s properties, as well as in novel experiments that take advantage of the enhanced beam quality that ELENA can provide. These research areas are in the heart of the pan-European research and training network AVA (Accelerators Validating Antimatter physics) which started in 2017. This contribution presents research results within AVA on the performance of ultra-thin diamond membranes, electron cooling and beam life time studies of low energy ion and antiproton beams, as well as efficient integration and performance optimization of cryogenic detectors in ELENA and associated trap experiments. These results are used to describe the optimum layout of a state-of-the-art low energy antiproton facility and associated experiments.

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paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPTS007

SARAF Equipped Cavity Test Stand (ECTS) at CEA

cavity, cryomodule, controls, EPICS

852

O. Piquet, C. Boulch, D. Chirpaz-Cerbat, G. Ferrand, F. Gohier, T.J. Joannem, G. Monnereau, Th. Plaisant
CEA-IRFU, Gif-sur-Yvette, France
D. Braud, P. Carbonnier, P. Guiho, L. Maurice, J. Plouin, P. Sahuquet, N. Solenne
CEA-DRF-IRFU, France
F. Gouit, A. Pérolat
CEA, Gif-sur-Yvette, France

CEA is committed to delivering a Medium Energy Beam Transfer line and a Super Conducting Linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3MeV to 35MeV or deuterons from 2.6 MeV to 40.1MeV. The SCL consists in 4 cryomodules separated by warm section housing beam diagnostics. The two first identical cryomodules hosts respectively 6 and 7 half-wave resonator (HWR) low beta (0.091) cavities 176MHz. In order to test the cavity with its tuner and coupler and validate some design consideration, the Equipped Cavity Test Stand (ECTS) has been designed and will be presented.

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paper received ※ 07 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS052

Simulation of Electric and Thermal Behavior of Cryogenic Three-cell Copper Accelerating Cavity for High Gradient Experiments

cavity, simulation, coupling, experiment

980

T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, Y. Takahashi
LEBRA, Funabashi, Japan

A C-band three-cell pi-mode accelerating cavity made of high purity copper is under design for use in ultra-high accelerating gradient experiments at a cavity temperature of 20 K. The basic configuration, consisting of mode converter, short circular waveguide and cells with round periphery, is the same as that which was previously employed in the cold model for a 2.6-cell photocathode electron gun cavity. Though the 0.6-cell part in the previous model is replaced with a full cell having a beam duct, the overall electric property of the cavity will not change significantly. The RF input coupling coefficient is adjusted to around 10 at 20 K, which is expected to be lowered significantly due to the increase in the surface resistance by the rapid temperature rise during a high power RF input. The results of the simulations on the electric field and the temperature rise along the cavity surface during the RF pulse are discussed in the report.

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paper received ※ 13 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPTS117

Exploration of High-Gradient Structures for 4th Generation Light Sources

cavity, FEL, linac, electron

1155

S.J. Smith, S. Biedron, S.I. Sosa Guitron
University of New Mexico, Albuquerque, USA
T.B. Bolin
Element Aero, Chicago, USA
B.E. Carlsten, F.L. Krawczyk
LANL, Los Alamos, New Mexico, USA
J.R. Cary, D.M. Cheatham
Tech-X, Boulder, Colorado, USA

As the energy, scale and therefore the cost of large-scale accelerator projects, such as X-ray free-electron lasers (XFELs) increases, new technologies must be developed in order to minimize costs and maximize efficiency wherever possible. One obvious way to reduce costs is to reduce the length of accelerating sections by utilizing higher accelerating gradients. Here we present the results of a study into the various structure options for FEL linacs, contrasting different frequencies, geometries and operating modes. An investigation into the possibility of using cryo-cooled travelling wave (TW) electron structures which allow for higher gradient operation by exploiting the anomalous skin effect is also detailed. Finally, we give simulation results from a number of commercial codes including VSim 9, for a hypothetical TW high gradient C-band structure design employing cryo-cooled technology. Breakdown effects, pulsed heating, tolerances, efficiencies and potential rf sources are also explored, all within the framework of typical FELs and their requirements.

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPMP006

Cryogenic Tests of the SPIRAL2 LINAC Systems

cavity, cryomodule, linac, operation

1240

A. Ghribi, P.-E. Bernaudin, R. Ferdinand, A.V. Vassal
GANIL, Caen, France

Two full cool-down of the SPIRAL2 superconducting LINAC have been performed in 2017 and 2018 respectively, followed by a total of around 5 months of tests at 4 K. Several cool-down strategies were tested, in order to minimize 100 K effect on the SC cavities. Helium bath regulations (level and pressure) have been tested and optimized. Effects of pressure instabilities and coupling with the cryogenic plant have also been observed. Cryogenic performances of each cryomodule have been measured. Low-level RF measurements were also performed on all cavities and showed unidentified modulations at frequencies around 5Hz. These turned out to be thermoacoustic oscillations (TAO) on the cryogenic lines, which generate important pressure instabilities. Several solutions to remove TAO and cure these instabilities have been tested and one has been successfully deployed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP006

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPMP045

The Protection Instrument for Cryogenic Phase Separator Pressure Relief Valve of TPS Beamline

controls, monitoring, software, operation

1350

C.C. Liang, C.Y. Chang, C.F. Chang, Y.H. Guo, M.H. Lee, C.Y.L. Liu, T.-C. Yu
NSRRC, Hsinchu, Taiwan

TPS (Taiwan Photon Source) beamlines have operated for three years after the successful commission in 2015. Recently, the electromagnetic activated pressure relief valve of cryogenic phase separator of beamline had malfunction due to the rust of its control circuits. After on site observation and temperature records, the water was found to be condensed around the outlet area due to fast temperature dropping near the valve as it was activated. Such situation would cause the rust of metal components due to humidity after a certain period of time. To avoid such event, fan is used to blow the condensed water and silicone heat belts are added to increase the local temperature with unique designed clamp for fixing the fan, sensors and safety circuit breaker. Via the temperature control system, the temperature monitoring, setting and the abnormal situation can be access on web page through Ethernet to make sure the proper operation of the protected devices. The instrument has been operated since Dec. 2018. After four months of operation, the moist situation has been improved and the relief valve is no longer frosted.

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paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP047

Upgrade of the Cryogenic Control System for SRF Modules at the Taiwan Light Source

controls, SRF, operation, interface

1356

F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, S.W. Chang, L.J. Chen, Y.T. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

An upgrade of the cryogenic control system for superconducting radio-frequency (SRF) modules of the Taiwan Light Source (TLS) has been completed. The biggest challenge was to recover all protection and operational functions, while minimizing the quantity of vented helium from SRF modules while replacing valve controllers. Gradually, this work was finished within several one- and ten-day scheduled machine shutdown periods for accelerator maintenance. No large helium vent nor pollution of the cryogenic system occurred during all component replacements and function verifications. Functions of the cryogenic electronics were improved, whereas the valve controllers are upgraded to new versions to increase reliability and availability. Communications with the data acquisition system was also secured by buffered signal processing module so that device shutdown of the data acquisition system will not interrupt the cryogenic valve operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP047

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paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP054

Investigations on Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18

vacuum, heavy-ion, synchrotron, operation

1372

L.H.J. Bozyk, S. Aumüller, P.J. Spiller
GSI, Darmstadt, Germany

The heavy ion synchrotron SIS18 at GSI will serve as injector ring for the FAIR-facility and provide high intensity heavy ion beams. The operation of such beams requires the usage of low charge states, which have high cross sections for ionization. To overcome this issue, many upgrade measure have been realized in the past decade, such as the installation of an ion catcher system with low desorption surfaces and coating 65% of the circumference of SIS18 with NEG to lower the static gas pressure. Since the vacuum dynamics during operation prevent the achievement of the intensity goals for FAIR, new concepts have to be developed, to increase the beam intensity. One idea is the installation of additional pumping speed in the form of cryogenic surfaces. Heavy residual gas components, which have the highest ionization cross sections can be cryopumped at moderate temperatures, i.e. already at 50-80 K. In fact, the only typical residual gas component which can not be pumped via cryosorption in this temperature regime is Hydrogen, which has a factor 50 lower ionization cross sections than Argon, the heaviest residual gas component. In this paper, we present a study of the integration of cryopanels into the vacuum chambers of SIS18.

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPTS006

Tests at High RF Power of the ESS Medium Beta Cryomodule Demonstrator

cavity, cryomodule, linac, status

1940

P. Bosland, C. Arcambal, F. Ardellier, S. Berry, A. Bouygues, E. Cenni, G. Devanz, T. Hamelin, X. Hanus, O. Piquet, J.P. Poupeau, B. Renard, P. Sahuquet
CEA-DRF-IRFU, France
C. Darve
ESS, Lund, Sweden
P. Michelato
INFN/LASA, Segrate (MI), Italy
G. Olivier, J.P. Thermeau
IPN, Orsay, France

CEA is in charge of the 30 elliptical medium and high-beta cryomodules to be installed in the ESS tunnel in Lund, Sweden. Before launching the assembly of the series cryomodules, CEA developed a medium-beta cryomodule technology demonstrator in a collaboration with IPNO, LASA and ESS. This paper briefly presents the cryomodule assembly and summarizes the main results of the high RF power tests performed in 2018 in a dedicated test stand in CEA Saclay. The main ESS requirements were reached: E_acc = 16.7 MV/m in cavities, Pforward = 1.1 MW in power couplers, RF pulses length = 3.6 ms at 14 Hz. The piezo tuners efficiently compensated the Lorentz forces detuning and could stabilize the accelerating field better than 1% over the full length of the expected ESS 2.86 ms beam pulse without any LLRF regulation system. Following this successful validation CEA started the assembly of the first ESS medium-beta series cryomodule

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paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS114

Electron Stimulated Desorption from Cryogenic NEG-Coated Surfaces

vacuum, electron, experiment, site

2193

R. Sirvinskaite, M.D. Cropper
Loughborough University, Loughborough, Leicestershire, United Kingdom
A.N. Hannah, O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Non-Evaporable Getter (NEG) coating has been used for years in many particle accelerators due to its advantages like evenly distributed pumping speed, low thermal outgassing, and low photon, electron and ion stimulated desorption yields. Although NEG coating has been tested at room temperatures intensively, there is little data on its behaviour at cryogenic temperatures. Tests in this environment are important for the Future Circular Collider (FCC) study and other accelerator facilities where the operational conditions of the beam screen are restricted to cryogenic temperatures. This work will provide some preliminary results on NEG properties at low temperatures, e.g. pumping speed and capacity, as well as its behaviour under electron bombardment, where electron stimulated desorption (ESD) yields will be calculated. The ternary Ti-Zr-V coating, deposited with dense and columnar structure, will be the first material to be tested at cryogenic temperatures in ASTeC Daresbury laboratory. The results were compared with the ones obtained at room temperature, offering an insight into the behaviour of NEG-coated cryogenic chambers when beam-induced effects are present.

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW020

Next Generation Cryogenic Current Comparator (CCC) for nA Intensity Measurement

shielding, pick-up, coupling, detector

2510

T. Sieber, D.M. Haider, H. Reeg, M. Schwickert, T. Stöhlker
GSI, Darmstadt, Germany
H. De Gersem, N. Marsic, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany
J. Golm, F. Schmidl, P. Seidel, V. Tympel
FSU Jena, Jena, Germany
M. Schmelz, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker
HIJ, Jena, Germany
J. Tan, G. Tranquille
CERN, Geneva, Switzerland

A Cryogenic Current Comparator (CCC) is an extremely sensitive DC-Beam Transformer based on superconducting SQUID technology. Recently, a CCC without a toroidal core and with an axially oriented magnetic shielding has been developed at the Institute of Photonic Technologies (IPHT) Jena/Germany. It represents a compact and lightweight alternative to the ’classical’ CCC, which was originally developed at PTB Braunschweig and is successfully in operation in accelerators at GSI and CERN. Excellent low-frequency noise performance was demonstrated with a prototype of this new CCC-type. Current measurements and further tests are ongoing, first results are presented together with simulation calculations for the magnetic shielding. The construction from lead as well as simplified manufacturing results in drastically reduced costs compared to formerly used Nb-CCCs. Reduced weight also puts less constraints on the cryostat. Based on highly sensitive SQUIDs, the new prototype device shows a current sensitivity of about 6 pA/Hz1/2 in the white noise region. The measured and calculated shielding factor is ~135 dB. These values, together with a significant cost reduction - resulting also from a compact cryostat design - opens up the way for widespread use of CCCs in modern accelerator facilities.

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WEPRB025

High Density Mapping for Superconducting Cavities

cavity, radiation, status, operation

2860

Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
Y. Fuwa
Kyoto University, Research Reactor Institute, Osaka, Japan
R.L. Geng
JLab, Newport News, Virginia, USA
H. Hayano
KEK, Ibaraki, Japan

High density mapping system for superconducting cavities are under development. Testing on the stiffener X-ray mapping system at JLAB showed consistent results in comparison with simultaneously taken GM tube or ion chamber output signals. The system provides better visi-bility as shown by data briefly reported here. In addition to the temperature and the X-ray mapping, a sensitive magnetic field mapping system with high spatial density is also under development. The magnetic field sensor is AF755B, whose operations at cryogenic temperatures are already reported by other group. Our development status using the magnetic field sensor will be reported.

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPRB098

Cryogenic RF Performance of Double-Quarter Wave Cavities Equipped with HOM Filters

cavity, HOM, operation, SRF

3043

S. Verdú-Andrés, I. Ben-Zvi, Q. Wu, B.P. Xiao
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
G. Burt, J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
R. Calaga, O. Capatina
CERN, Geneva, Switzerland
N.A. Huque, E.A. McEwen, H. Park, T. Powers
JLab, Newport News, Virginia, USA
Z. Li, A. Ratti
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE through BSA LLC under contracts No. DE-AC02-98CH10886, No. DE-SC0012704, and the US LHC Accelerator Research Program (LARP) and by the EU HL-LHC Project.
Crab cavities are one of the several components included in the luminosity upgrade of the Large Hadron Collider (HL-LHC). The cavities have to provide a nominal deflecting kick of 3.4 MV per cavity while the cryogenic load per cavity stays below 5 W. Cold RF tests confirmed the required performances in bare cavities, with several cavities exceeding the required voltage by more than 50%. However, the first tests of a Double-Quarter Wave (DQW) cavity with one out of three HOM filters did not reach the required voltage. The present paper describes the studies and tests conducted on a DQW cavity with HOM filter to understand the limiting factor. The recipe to meet the performance specification and exceed the voltage requirement by more than 35% is discussed.

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THYYPLS2

Different Versions of Cryogenic Current Comparators with Magnetic Core for Beam Current Measurements

shielding, pick-up, operation, proton

3431

J. Golm, F. Schmidl, P. Seidel
FSU Jena, Jena, Germany
H. De Gersem, N. Marsic, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany
M.F. Fernandes, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.F. Fernandes, J. Tan, C.P. Welsch
CERN, Geneva, Switzerland
M.F. Fernandes, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
D.M. Haider, F. Kurian, M. Schwickert, T. Sieber, T. Stöhlker
GSI, Darmstadt, Germany
R. Neubert
Thuringia Observatory Tautenburg, Tautenburg, Germany
M. Schmelz, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker, V. Tympel
HIJ, Jena, Germany
V. Zakosarenko
Supracon AG, Jena, Germany

For more than 20 years Cryogenic Current Comparators (CCC) are used to measure the current of charged particle beams with low intensity (nA-range). The device was first established at GSI in Darmstadt and was improved over the past two decades by the cooperation of institutes in Jena, GSI and CERN. The improved versions differ in material parameters and electronics to increase the resolution and in dimensions in order to meet the requirements of the respective application. The device allows non-destructive measurements of the charged particle beam current. The azimuthal magnetic field which is generated by the beam current is detected by low temperature Superconducting Quantum Interference Device (SQUID) current sensors. A complex shaped superconductor cooled down to 4.2 K is used as magnetic shielding and a high permeability core serves as flux concentrator. Three versions of the CCC shall be presented in this work: (1) GSI-Pb-CCC which was running at GSI Darmstadt in a transfer line, (2) CERN-Nb-CCC currently installed in the Antiproton Decelerator at CERN and (3) GSI-Nb-CCC-XD which will be operating in the CRYRING at GSI 2019. Noise, signal and drift measurements were performed in the Cryo-Detector Lab at the University of Jena.

Slides THYYPLS2 [4.344 MB]

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THPTS001

Development of Cryogenic Suspension in the ANU 8t Superconducting Solenoid With Iron Yoke

solenoid, vacuum, experiment, EPICS

4103

S.T. Battisson, N.R. Lobanov, D. Tsifakis, T.B. Tunningley
Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
J.F. Smith
University of Surrey, Department of Physics, Guildford, United Kingdom

Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism.
An 8 Tesla superconducting solenoid was commissioned at The Australian National University to make precision measurements of fusion cross-sections. Forces between the solenoid and the iron yoke that houses it must always be maintained within safe limits and precision location of the solenoid coil is necessary to achieve this. Thermal contraction of components can impact the locating structure of the solenoid coil, leading to unsafe forces. Improvements to this structure allowed successful completion of the first fusion measurements with the 8T solenoidal separator, and demonstrated that it is now ready for a program of fusion measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS001

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS011

Design, Production, and Testing of Superconducting Magnets for the Super-FRS

dipole, quadrupole, octupole, superconducting-magnet

4128

H. Müller, E.J. Cho, G. Golluccio, C. Roux, H. Simon, K. Sugita, M. Winkler
GSI, Darmstadt, Germany
H. Allain, M. Daly, P. Grafin, A. Madur, J.-E. Munoz-Garcia, L. Quettier, H. Reymond
CEA-IRFU, Gif-sur-Yvette, France
A. Borceto, G. Drago, G. Valesi, D. Ventura
ASG, Genova, Italy
J. Lucas
Elytt Energy, Madrid, Spain
L.X. Van Den Boogaard
CERN, Geneva, Switzerland

The Super FRS is a two-stage in flight separator to be built next to the site of GSI, Darmstadt, Germany as part of FAIR (Facility for Anti-proton and Ion Research). Its purpose is to create and separate rare isotope beams and to enable the mass measurement also for very short lived nuclei. Due to its three branches a wide variety of experiments can be carried out in frame of the NUSTAR collaboration. Due to the large acceptance needed, the magnets of the Super-FRS have to have a large aperture and therefore only a superconducting solution is feasible. A superferric design with superconducting coils was chosen in which the magnetic field is shaped by an iron yoke. For the dipoles this iron yoke is at warm and only the coils are incorporated in a cryostat. The multiplets, assemblies of quadrupoles and higher order multipole magnets, are completely immersed in a liquid Helium bath. With the exception of special branching dipoles all superconducting magnets of Super-FRS have been contracted and are being built by Elytt in Spain (dipoles) and ASG in Italy (multiplets). The cold test of all magnets will take place in a dedicated test facility at CERN. This contribution will present the status of manufacturing of dipoles and multiplets, and also gives a short overview on the test facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS011

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS029

Optimization of Staggered Array Undulator

undulator, solenoid, electron, site

4171

L.J. Chen, Q.K. Jia
USTC/NSRL, Hefei, Anhui, People’s Republic of China
M. Li, P. Li, J. Wang, D. Wu, D.X. Xiao, L.G. Yan, X. Yang
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

Funding: the National Key Research and Development Program of China under Grant No. 2016YFA0402003 the National Nature Science Foundation of China under Grant No. 11611140102.
The staggered array undulator consists of staggered poles and solenoid coils that form a periodically aligned transverse magnetic field in the pole gap. The addition of magnets in the longitudinal gap between the poles further enhances the peak field strength of the undulator. A method of enhancing the peak field strength of the undulator using cryogenic temperature permanent magnets and adding side magnets has been studied. The remanence of the magnet will increase at low temperatures and the peak field strength of the undulator will increase. The side magnets do not increase the maximum peak field strength of the undulator, but can reduce the solenoid magnetic field requirements and reduce the solenoid volume and cost. The influence of the special magnetic pole and magnet shape on the peak field strength of the undulator has also been studied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS029

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS066

Beam Impact Experiment of 440GeV/p Protons on Superconducting Wires and Tapes in a Cryogenic Environment

experiment, proton, interface, simulation

4264

A. Will, A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany
Y. Bastian, B. Bordini, M. Favre, B. Lindstrom, M. Mentink, A. Monteuuis, A. Oslandsbotn, R. Schmidt, A.P. Siemko, K. Stachon, M.P. Vaananen, A.P. Verweij, A. Will, D. Wollmann
CERN, Geneva, Switzerland
M. Bonura, C. Senatore
UNIGE, Geneva, Switzerland
A. Usoskin
BRUKER HTS GmbH, Alzenau, Germany

The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failure cases. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, directly or via secondary particle showers. The interaction leads to energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb₃Sn strands as well as YBCO tape in a cryogenic environment to microsecond 440 GeV/p proton beams. The irradiated samples were extracted and are being analyzed for their superconducting properties, such as the critical transport current. This paper describes the experimental setup as well as the first results of the visual inspection of the samples.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS066

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS071

Performance of TPS Cryogenic Permanent Magnet Undulators at NSRRC

undulator, vacuum, permanent-magnet, controls

4278

J.C. Huang, C.S. Yang, C.K. Yang
NSRRC, Hsinchu, Taiwan
H. Kitamura
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
T. Kohda
NEOMAX Engineering Co., Ltd., Tokyo, Japan

Development of cryogenic permanent magnet un-dulators (CPMUs) is the most recent activity for Phase-II beamlines at the Taiwan Photon Source. A hybrid-type CPMU with a period length of 15 mm, based on PrFeB permanent-magnet materials, is under construc-tion. A maximum effective magnetic field of 1.33 T at a gap of 4 mm is obtained at 80 K.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS071

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS080

Novel Technique Ion Assisted In-Situ Coating of Long, Small Diameter, Accelerator Beam Pipes with Compacted Thick Crystalline Copper Film

cathode, lattice, vacuum, plasma

4301

A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, G.T. McIntyre, S. Verdú-Andrés
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Although great progress was made with in-situ copper coating, by magnetron sputtering, to address the high room temperature resistivity, literature indicates that conventionally deposited thick copper films do not retain the same RF conductivity at cryogenic temperatures, since straightforward deposition tends to result in films with columnar structure and other lattice defects, which cause significant conductivity degradation at cryogenic temperatures. We utilize energetic ions for ion assisted deposition (IAD) to reduce lattice imperfections, for coating. IAD that can in-situ coat long small diameter tubes with compacted crystalline structure thick copper films has been developed. Moreover, development of techniques and devices can resurrect IAD for other applications, which have been impractical and/or not viable economically. Comparison of conductivity at cryogenic temperatures between straight magnetron physical vapor deposition and IAD will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS080

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS081

Novel Apparatus and Technique for Measuring RR Resistivity of Tube Coatings at Cryogenic Temperatures

lattice, cavity, experiment, vacuum

4304

A. Hershcovitch, J.M. Brennan, R. Than, S. Verdú-Andrés, Q. Wu
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A unique apparatus for measuring RF resistivity of tubes and coated tubes at cryogenic temperatures is operational at BNL, which to our knowledge is the first of its kind. A folded quarter wave resonator structure of 300 mm length accesses a wide range of frequencies. The structure is cooled in liquid He bath at 4 K. All internal resonator components (except for test samples) were fabricated out of superconducting materials. Consequently, when the resonator is cooled, the bulk of the losses are due to the copper coating. The RF resistivity is determined from Q measurements, since for a fixed geometry the quality factor of a resonant cavity is proportional to the square root of the conductivity. The RF input loop and the output signal antenna are adjustable when cold via bellows to control matching to each cavity mode. The Q values of 10 resonant modes between 180 and 2500 MHz are deduced from the bandwidth of the S21 response Network Analyzer measurements. CST MicroWave Studio is used to extract the resistivity of the samples from the Q measurements. Resistivity results of solid Cu tube, 2, 5, & 10 μm Cu coated 316LN stainless steel RHIC beam tubes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS081

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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