EPAC08 - List of Keywords (superconductivity)

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superconductivity

Paper	Title	Other Keywords	Page
MOPP130	SRF Technology-Past, Present and Future Options	vacuum, electron, controls, radio-frequency	865
	G. Myneni, M. Hutton Jefferson Lab, Newport News, Virginia
	Superconducting radiofrequency cavities for all recent projects (CEBAF, SNS, KEKB, and TTF) have been built from high purity polycrystalline niobium with a residual resistance ratio (RRR) greater than 250. The procedures and processes used from the initial production of the high RRR polycrystalline niobium sheets to the finished cavities are complex, numerous and very expensive, and the yield of SRF cavities meeting the performance specifications is very low. CBMM – Jefferson Lab invented the large grain and single crystal niobium technologies, and the use of niobium sliced directly from the ingots is expected to change the SRF technology outlook with fewer, and more streamlined, production processes that will not only be cost effective but also generate high yield. In this paper we will show that less stringent commercial niobium specifications are required, and explore the processes and procedures that will lay the foundation for producing SRF cavities with good quality factors at high peak magnetic fields in order to make this technology friendlier for future scientific and technological applications.

MOPP137	MultiPac 2.1 - Multipacting Simulation Package with a 2D FEM Field Solver for a Microsoft Windows System	electron, simulation, RF-structure, vacuum	880
	Y. M. Li, S. An, Y.-S. Cho, L. Zhang KAERI, Daejon P. Ylä-Oijala Helsinki University of Technology, Helsinki
	MultiPac 2.1 is a multipacting simulation package for analyzing electron multipacting in axisymmetric RF structures with TM_0nl mode, such as RF cavities, coaxial input couplers and ceramic windows. The original package was written by P. Ylä-Oijala, and works with MATLAB 5.0 or 6.0 on Linux operating system. In order to use this code easily for Microsoft Windows customers, we have transferred the MultiPac 2.1 from the Linux system to the Microsoft Windows system. The revised MultiPac can work with Microsoft Windows MatLab 6.0 or later editions smoothly. In this paper, the installation and operation of the Windows MutiPac 2.1 have been introduced. This work was supported by the 21C Frontier R&D program in Ministry of Science and Technology of the Korean Government.

MOPP146	The Coaxial Tuner for ILCTA_NML at Fermilab	cryogenics, vacuum, linear-collider, collider	895
	A. Bosotti, C. Pagani, N. Panzeri, R. Paparella INFN/LASA, Segrate (MI)
	The piezo Blade Tuner prototype has been successfully tested inside the horizontal cryostat, CHECHIA, at DESY and extensive tests at BESSY are planned. As suggested by the cold test results, a few minor modifications have been implemented and a set of 8 improved devices is under construction for the installation in the second module of ILCTA at Fermilab. This reviewed design, together with a simplified helium tank in prototyping, should hopefully fulfill also the XFEL requests in term of performances and cost. In particular the use of thicker blades and their slightly different distribution along the circumference produces the increase of the tuner strength and stiffness that is needed in order to fulfill the pressure vessel regulations for qualification. As in the past, two equivalent devices, respectively in titanium and stainless steel, have been designed to maintain open the possibility of the use of a SS helium vessel once the required technology were developed. The results of the extensive mechanical tests performed to validate the estimated performances and life time are also presented.

MOPP148	Design of a Magnetic Shield Internal to the Helium Vessel of SRF Cavities	shielding, linac, background, controls	898
	P. Pierini, S. Barbanotti, L. Monaco, N. Panzeri INFN/LASA, Segrate (MI)
	The TRASCO elliptical cavities for intermediate velocity protons (β=0.47) employ a coaxial cold tuner of the blade type. To meet the perfomance goals of the 700 MHz cavities in the foreseen horizontal cryostat tests, the cavities are being equipped with a magnetic shield which lies internally to the cavity helium vessel and has a simple mechanical design and assembly procedure.

MOPP159	Results of Vertical Tests for the KEK-ERL Single Cell Superconducting Cavities	acceleration, linac, pick-up, insertion	925
	K. Umemori, T. Furuya, T. Takahashi KEK, Ibaraki H. Sakai, K. Shinoe ISSP/SRL, Chiba M. Sawamura JAEA/ERL, Ibaraki
	The development of the superconducting cavities is indispensable for realizing the 5 GeV-class energy recovery linacs. The KEK-ERL cavity had been recently designed. Its features are the optimized cell shapes and adoption of the enlarged beampipes with eccentric-fluted structures. In order to confirm our cavity design, two types of single cell cavities had been fabricated. One is a center-cell type cavity, whose aim is a validation of the cell shape, and another is an end-cell type cavity, which has complex structure such as the eccentric-fluted beampipes. After applying a series of surface treatments, we had assembled the cavities and performed vertical tests at KEK D10 area. Promising results have been obtained. In this presentation, we will present the results of vertical tests for these cavities.

MOPP164	Improvements in Field Emission: A Statistical Model for Electropolished Baked Cavities	simulation, site	934
	J. L. Wiener, H. Padamsee Cornell University, Ithaca, New York
	A statistical model for field emission developed in 1993 has been applied to characterize the improvement in field emitter properties and field emitter occurrence due to improvements in treatment methods for 9-cell TESLA-style cavities. The improved treatments are electropolishing, high pressure rinsing and baking (120C, 48 hours). We model the Q vs. Eacc data from 24 9-cell tests and 32 1-cell tests, all conducted at TTF by DESY. The statistical model is able to successfully simulate the observed yields by applying a factor of 3 decrease in emitter density over the emitter density prevailing for treatments in 1993, which did not include high pressure rinsing. Both simulation and data show that at Eacc = 70 MV/m the yield for field emission power less than 100 watts (Q > 8x10⁹) is less than 20%. To raise this yield to 80% will require new treatments that will reduce the emitter density by another factor of 3 at least. Further comparisons of field emission behavior will be made with data for alcohol rinsed cavities.

MOPP166	Control System for a PEFP FPC Baking System	controls, vacuum, monitoring, proton	940
	L. Zhang, S. An, Y.-S. Cho, Y. M. Li, Y. Z. Tang KAERI, Daejon
	In order to bake PEFP Fundamental Power Couplers (FPC) before their RF conditioning, a PEFP baking system has been designed. A control system for the baking system has been completed by using the Labview 8.2 and A-B SLC-500 PLC. In this paper, the server and client communication technology based on OLE for a Process Control (OPC) and a Labview 8.2 Datalogging and Supervisory Control (DSC) Module are described. The program for the SLC-500 PLC with four I/O modules has been written. The mechanical design and control process are described.

TUPC036	Multi-wire Profile Monitor for J-PARC 3GeV RCS	injection, electron, linac, radiation	1131
	S. Hiroki, N. Hayashi, M. Kawase, F. Noda, P. K. Saha, H. Sako, H. Takahashi, A. Ueno JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken Y. Arakida, S. Lee, T. Toyama KEK, Ibaraki
	A set of six multi-wire profile monitors (MWPMs) has been installed in the injection line and the successive H0 dump line of the RCS (Rapid-Cycling Synchrotron), and contributed to the initial RCS commissioning for establishing an optimum injection orbit. The Au coated W wires (0.1 mm dia.) for the H^- beam detection are fixed to a ceramic wind frame for two directions (horizontal and vertical with 17.7 ^o tilt, typically 51 wires with 2.9 mm or 9.5 mm distance), and the frame can be scanned for horizontal or vertical direction by using a stepping-motor driven actuator. A combination of the 17.7 ^o tilt wires and the precise scan function provides two step measurements, i.e. a rough profile is obtained only at one shot, and a detailed profile is measured for typically 101 shots (10 mm scan at 0.1 mm interval) thereafter. The beam induced charge signals are amplified by the instrumentation pre-amps located in a basement sub-tunnel at distances of 30-40 m from the frame through the shielded twisted pair cables. The signals are further transferred to the sample, hold and multiplex circuits at the ground floor. The digitized profile data are processed to the Gaussian fitting.

TUPP090	A Kinetic Model of Multipaction for SRF Cavities for Accelerator Driven Sub-Critical System (ADSS)	electron, simulation, electromagnetic-fields, proton	1741
	S. Ghatak, N. Gupta IITK, Kanpur A. S. Dhavale, K. C. Mittal BARC, Mumbai
	This work simulates multipaction in a 700 MHz elliptical SRF cavity. The cavity design was optimized using SUPERFISH. Then the electromagnetic field was re-computed with FEMLAB, a package using the finite element method, to obtain a more accurate field-mapping, and to make the field values available for computation of multipaction. In the multipacting subroutine, electrons were assumed to be released into the system from various points with different initial parameters. The electrons trajectories were tracked until they hit the cavity surface. Leap-frog scheme was used to solve the Lorentz force equation for primary electrons, as it is easy to use and is accurate up to second order. The position, velocity, phase and kinetic energy of primary electrons at each time step were calculated and stored. An interpolation function was used to calculate secondary emission yield (SEY) at different impact energies. With the emission of secondary electrons, their trajectories too were tracked along with primary electrons, in order to identify parameters responsible for multipaction. By repeating this process for large number of electrons, the multipacting trajectories were identified.

TUPP111	Magnetic Design Improvement and Construction of the Large 90o Bending Magnet of the Vertical Beam Delivery Line of CNAO	ion, heavy-ion, proton, controls	1782
	W. Beeckman, S. Antoine, F. Forest, J. L. Lancelot, M. J. Leray, T. Planche Sigmaphi, Vannes P. Fabbricatore INFN Genova, Genova C. Priano, M. Pullia CNAO Foundation, Milan
	The CNAO (Centro Nazionale di Adroterapia Oncologica) is the medical center dedicated to the cancer therapy, under construction in Italy. Protons with energy ranging from 60 to 250 MeV and carbon ions with energy 120 to 400 MeV/u will be delivered to patients in three different treatment rooms, of which one is served with both horizontal and vertical beams. The vertical line requires a 70 tons 90^o bending magnet providing 1.81 T in a good field region of x = ± 100 by y = ± 100 mm² with an integrated field quality (ΔBL/BL) at all field levels ≤ ± 2×10^-4. Starting from the experience matured when constructing the large bending magnet for HICAT gantry, we have developed a design able to meet these more stringent requirements in both 2D and 3D and special attention was paid to the study of manufacturing tolerances

WEOBM03	Development of a High Resolution Camera and Observations of Superconducting Cavities	linac, electron, superconducting-RF	1956
	Y. Iwashita, Y. Tajima Kyoto ICR, Uji, Kyoto H. Hayano KEK, Ibaraki
	An inspection system of the interior surface of superconducting RF cavities is developed in order to study the relation between the achievable field gradient and the defects of the interior surface. The achieved resolution is about 7 microns/pixel. So far there are good correlations between locations identified by a thermometry measurements and positions of defects found by this system. The heights or depths can be also estimated by measuring wall gradients for some well-conditioned defects. The detailed system and the data obtained from the system will be described.
	Slides

WEPC121	Magnetic Measurement Device for Superconductive Undulator Mock-up Coils at ANKA	undulator, vacuum, synchrotron, electron	2291
	E. M. Mashkina, B. K. Kostka, E. Steffens University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen T. Baumbach, A. Bernhard, D. Wollmann University of Karlsruhe, Karlsruhe S. Casalbuoni, A. W. Grau, M. Hagelstein, R. Rossmanith FZK, Karlsruhe
	A device for precise magnetic measurements of superconductive coils was designed, built and installed at the synchrotron radiation source ANKA, Forschungszentrum Karlsruhe. Accurate magnetic field measurements are a prerequisite for the characterization and optimization of insertion devices. The new device allows measuring the magnetic field magnitude of test coils with a longitudinal precision of 10 μm using a 2D Hall probe bench. The cylindrical liquid He cryostat allows mounting coils of maximum dimensions 50 cm in length and 30 cm in diameter. The set-up is computer controlled. The contribution will present the new device as well as the results obtained.

WEPD014	Magnets for the MANX 6-D Muon Cooling Demonstration Experiment	dipole, quadrupole, multipole, simulation	2434
	V. S. Kashikhin, N. Andreev, V. Kashikhin, M. J. Lamm, K. Yonehara, A. V. Zlobin Fermilab, Batavia, Illinois M. Alsharo'a, R. P. Johnson, S. A. Kahn, T. J. Roberts Muons, Inc, Batavia
	MANX is a 6-dimensional muon ionization-cooling experiment that has been proposed to Fermilab to demonstrate the use of a helical cooling channel (HCC) for muon beam emittance reduction for future muon colliders and neutrino factories. The HCC for MANX has solenoidal, helical dipole, and helical quadrupole magnetic components, which diminish as the beam loses energy as it slows down in the liquid helium absorber inside the magnet. The proposed magnet system design is comprised of coil rings positioned along a helical path, which will provide the desired solenoidal and helical dipole and quadrupole fields. Additional magnets that provide emittance matching between the HCC and the upstream and downstream spectrometers are also described. The results of a G4Beamline simulation of the beam cooling behavior of the magnet and absorber system will be presented.

WEPD015	Design Studies of Magnet Systems for Muon Helical Cooling Channels	dipole, beam-cooling, quadrupole, target	2437
	V. Kashikhin, V. S. Kashikhin, M. J. Lamm, M. L. Lopes, A. V. Zlobin Fermilab, Batavia, Illinois M. Alsharo'a, R. P. Johnson, S. A. Kahn Muons, Inc, Batavia
	Helical cooling channels consisting of a magnet system with superimposed solenoid, helical dipole and quadrupole fields, and a pressurized gas absorber in the aperture, promise high efficiency in providing 6D muon beam cooling for a future Muon Collider and some other applications. Two alternative designs of the magnet system for the helical cooling channel are being investigated at the present time. The first one is based on a straight, large aperture solenoid with helical dipole and quadrupole coils. The other one is based on a spiral solenoid which generates the main solenoid field and the helical dipole and quadrupole components. Both concepts have been developed and compared for the MANX experiment. In this paper we continue design studies and comparison of these two concepts for the high field sections of a helical cooling channel. The results of magnetic and mechanical analysis as well as the superconductor choice and specifications will be presented and discussed.

WEPP099	Results from Atomic Layer Deposition and Tunneling Spectroscopy for Superconducting RF Cavities	scattering, vacuum, coupling, electron	2749
	J. Norem, J. W. Elam, M. J. Pellin ANL, Argonne, Illinois C. Z. Antoine CEA, Gif-sur-Yvette L. Cooley Fermilab, Batavia, Illinois J. F. Moore MassThink LLC, Naperville, IL Th. Proslier, J. Zasadzinski IIT, Chicago, Illinois
	Atomic Layer Deposition is a process that synthesizes materials in successive monolayers, at rates on the order of 1 micron/hour. We have been using this technique at Argonne as a possible way to improve both superconducting rf (SCRF) and normal rf structure performance. Initial experiments have led to a new model of high field Q-slope and new ways of controlling SCRF surfaces, as well as suggesting ways to significantly improve the operating gradients of both superconducting and normal structures. We have also been testing this technique in superconducting structures. Initial measurements show significant improvement over “cavity-grade” Nb samples.

THXM02	Development of the KEK-B Superconducting Crab Cavity	electron, positron, cryogenics, acceleration	2927
	K. Hosoyama, K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono, Y. Yamamoto KEK, Ibaraki H. Hara, K. Okubo, K. Sennyu, T. Yanagisawa MHI, Kobe
	The development of the KEK-B superconducting crab cavity, including the design, production, tests and latest parameter performances should be described in this talk.
	Slides

THPC110	Investigation of Helical Cooling Channel	emittance, simulation, coupling, quadrupole	3233
	K. Yonehara, V. Balbekov Fermilab, Batavia, Illinois
	A helical cooling channel (HCC) has been proposed to quickly reduce phase space of muon beams. It is composed of solenoidal and helical coils to provide focusing and dispersion needed for the six-dimension cooling. A comprehensive investigation of the HCC is performed in presented work including theoretical analysis, particle tracking and Monte Carlo simulation. These results are also compared with the past simulation results* to confirm the helical cooling theory. Optimization of the channel and estimation of its ultimate performances are presented. Y. Derbenev and R. P. Johnson. PRSTAB 8, 041002 (2005). *K. Yonehara et al. TPPP052, Particle Accelerator Conference 2005.