EPAC 2006 - Classification:07 Accelerator Technology/T26 Subsystems, Technology and Components, Other

07 Accelerator Technology

T26 Subsystems, Technology and Components, Other

Paper	Title	Page
TUYFI01	Gantry Design for Proton and Carbon Hadrontherapy Facilities	964
	U. Weinrich GSI, Darmstadt
	Using an isocentric gantry improves the efficiency and the flexibility of cancer treatments with ion beams (hadrontherapy). After an overview of the constraints imposed to these heavy equipments the gantries constructed for both proton and carbon ion facilities will be described. Finally, the new studies undertaken to decrease the cost of such equipments will presented.
	Transparencies
THPCH158	A Phased-locked S.A.M. Mode-locked Laser for the ELSA Photoinjector	3164
	V. Le Flanchec, P. Balleyguier CEA, Bruyères-le-Châtel
	A new laser oscillator has been developed for the ELSA photoinjector. It is a fibered-diode-pumped mode-locked Nd:YVO4 laser, with a completely passive cooling design. Mode-locking is achieved by a saturable absorber mirror. Such a passive laser oscillator must be synchronized with the ELSA electron bunches. A phased-locked loop has been developed for that purpose. We present the main design aspects resulting from the high stability requirement of ELSA. The first electron spectra measurements show the high level of energy stability achieved. We also present improvements in the laser injection system leading to a higher transverse stability, a more uniform cathode illumination, and a better transmission of the whole system.
THPCH159	Analysis of Microphonic Disturbances and Simulation for Feedback Compensation	3167
	M. Luong, P. Bosland, G. Devanz, E. Jacques CEA, Gif-sur-Yvette
	For FEL projects based on a superconducting linac operating in CW mode, the RF power optimization finally comes up against the microphonics disturbances, which result in an unpredictable detuning of the cavities. A new piezoelectric tuner was developed and mounted on a TTF 9-cell cavity with an appropriate instrumentation. This system enables a full characterization of the disturbances and the tuner behavior. First measurements were made in a horizontal cryomodule at 4.2 K. They set a basis for simulations to assess the possibility of a feedback compensation, which is usually credited as impracticable. The outcome of such a compensation is also shown in terms of acceleration voltage amplitude and phase residual errors.
THPCH160	Theoretical Study and Experimental Result of the RF Coupler Prototypes of Spiral 2	3170
	Y. Gómez-Martínez, D. Bondoux, JM. Carretta, J.-M. De Conto, M. Fruneau, A. Garrigue, D. Marchand, R. Micoud, E. Vernay, F. Vezzu LPSC, Grenoble P. Balleyguier CEA, Bruyères-le-Châtel M. Di Giacomo GANIL, Caen
	Spiral 2 is a 40 MeV superconducting linac under construction at GANIL. The RF couplers have to provide a 12 kW CW power to the cavities at 88 MHz. Two solutions corresponding to 2 different technologies have been designed and 2 prototypes have been built. We present the technical proposals and issues as well as the results (manufacturing, test at low and high power, multipacting…) leading to the final choice.
THPCH161	Status of the Polarized Electron Gun at the S-DALINAC	3173
	C. Heßler, M. Brunken, J. Enders, H.-D. Gräf, G. Iancu, Y. Poltoratska, M. Roth TU Darmstadt, Darmstadt W. Ackermann, W.F.O. Müller, N. Somjit, B. Steiner, T. Weiland TEMF, Darmstadt K. Aulenbacher IKP, Mainz
	Aiming at an extension of the experimenting capabilities for nuclear structure physics at low momentum transfer at the superconducting Darmstadt electron linear accelerator S-DALINAC, a polarized electron gun is being constructed. The new injector will be able to supply the S-DALINAC with 100 keV polarized electrons and should complement the present, unpolarized thermionic source. The design requirements are a degree of polarization of at least 80%, a mean current intensity of 0.06 mA and a 3 GHz cw structure. The basic design of the gun was adapted from the source of polarized electrons at MAMI, Mainz, and optimized in various simulations. The active material is a strained layer GaAs crystal which is exposed to an 830 nm pulsed laser beam. We report on the status of the polarized source, the preparation setup and a test beam line. K. Aulenbacher et al., Nucl. Instrum. Meth. A 391, 498 (1997).
THPCH163	"Oligo-crystalin" Niobium / Large Grain Niobium Discs, Directly Cut from Ingot	0
	B. Spaniol W.C. Heraeus GmbH, Materials Technology Dept., Hanau
	"Oligo-crystalin" Niobium ingots with very large grains (diameter more than 200 mm) can be perfectly used as start material to cut Niobium discs to form half-cells for SCRF cavities. Caused by the minimum of remaining grain boundaries, the properties of these discs are very promising for the use in SCRF cavities. In addition to the technical properties of such material also the cost benefit is promising. The new production way to cut the discs directly from the ingot is less expensive than the "traditional" sheet rolling process. As a positive side effect, the risk of contaminations is minimized due to the reduced number of production steps.
THPCH164	Progress and Status of the MICE Project	3176
	A.P. Blondel DPNC, Genève P. Drumm CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The design of a Neutrino Factory (NF) has been the subject of several physics studies. For a NF based on a stored high energy muon beam, a potential key technology that has a significant impact on its cost and practicality is the ability to cool rapidly the muon beam prior to acceleration. The muon ionisation cooling experiment (MICE), currently being constructed at the Rutherford Appleton Laboratory (UK), is a demonstration of emittance cooling in a linear cooling channel. A new muon beam line and the basic infrastructure for MICE are funded, and a muon beam is under construction with an expected availability in spring 2007. The experiment will be methodically assembled over the following few years to bring the beam through RF accelerating cavities and liquid hydrogen absorbers and confined by a solenoidal magnetic field. The emittance of the beam before and after the cooling channel is measured in tracking spectrometers. The current status of the beam line and infrastructure build and of the components of MICE is presented.
THPCH165	ERLP Quantum Efficiency Scanner	3179
	P.A. Corlett, J.H.P. Rogers CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Energy Recovery Linac Prototype (ERLP) under construction at Daresbury Laboratory will utilise a photoinjector as its electron source. In order to characterise the performance of the photo-cathode wafer, a low power laser is scanned across its surface and the resultant current measured to build up a map of the quantum efficiency of the wafer.
THPCH166	The Timing System for Diamond Light Source	3182
	Y.S. Chernousko, A. Gonias, M.T. Heron Diamond, Oxfordshire T. Korhonen PSI, Villigen E. Pietarinen, J. Pietarinen MRF, Helsinki
	The Diamond timing system is the latest generation development of the design, principles and technologies currently implemented in the Advanced Photon Source and Swiss Light Source timing systems. It provides the ability to generate reference events, distribute them over a fibre-optic network, and decode and process them at the equipment to be controlled. The timing system is closely integrated within the Diamond distributed control system, which is based on EPICS. The Diamond timing system functionality and performance, and first operational experiences in using the timing system during the commissioning of the accelerators, are presented in this paper.
THPCH167	Commissioning of the Diamond Pre-injector Linac	3185
	C. Christou, V.C. Kempson Diamond, Oxfordshire K. Dunkel, C. Piel ACCEL, Bergisch Gladbach
	Commissioning of the linac for the Diamond Light Source (DLS) was completed in October 2005. The linac was supplied by Accel Instruments as a complete system, with DLS providing beam diagnostics, beam analysis software, control system hardware and standard vacuum components. Much of the beam analysis was carried out using the first part of the Linac to Booster transfer line (LTB), which was designed and built by DLS. Operation of the linac and LTB at 100 MeV in long-pulse and short-pulse modes of operation was demonstrated, and all operational parameters were measured to be within specification.
THPCH168	RF Distribution System of the Diamond Master Oscillator	3188
	A.V. Watkins, M. Jensen, M. Maddock, S.A. Pande, S. Rains, D. Spink Diamond, Oxfordshire
	A modular RF distribution system has been designed and built at Diamond Light Source to distribute the master oscillator (MO) signal. The system will deliver a low noise, phase stable 500 MHz signal to multiple points of use around the synchrotron facility. Providing phase stability and preserving noise performance over the distances required (up to 300m) have been the main design challenges. A modular approach provides future flexibility, and this paper describes each component, outlining design choices, components used, construction details and test results.
THPCH169	Design, Manufacturing and Integration of LHC Cryostat Components: an Example of a Collaboration between CERN and Industry	3191
	M. Canetti, F.G. Gangini RIAL VACUUM S.p.A, Parma N. Bourcey, T. Colombet, V. Parma, I. Slits, J.-P.G. Tock CERN, Geneva
	The components for the LHC cryostats and interconnections are supplied by the European industry. The manufacturing, assembly and testing of these components in accordance with CERN technical specifications require a close collaboration and dedicated approach from the suppliers. This paper presents the different phases of design, manufacturing, testing and integration of four LHC cryostat components supplied by RIAL Vacuum (Parma, Italy), including 108 insulation vacuum barriers, 482 cold-mass extension tubes, 115 cryostat vacuum vessel jumper elbows and 10800 interconnection sleeves. The Quality Assurance Plan, which the four projects have in common, is outlined. The components are all leak-tight thin stainless steel assemblies (< 10^-8 mbar l/s), most of them operating at cryogenic temperature (2 K), however each having specific requirements. Therefore the peculiarities of each component are presented with respect to manufacturing, assembly and testing. These components are being integrated at CERN into the LHC cryostats and interconnections, which allowed validating the design and production quality. The major improvements and difficulties will be discussed.
THPCH170	Reduction of Dark Current in SPring-8 Linac	3194
	T. Kobayashi, T. Asaka, H. Dewa, H. Hanaki, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken
	In the SPring-8 linac, removal of dark currents generated from an injector part has been studied to enhance the bunch purity of stored beam in the SPring-8 storage ring. We already succeeded in reduction of the dark currents from a thermionic electron gun by a beam deflector of parallel plate electrodes. However, dark currents are also generated in accelerating structures due to the high electric fields. We have been studying removal of the dark currents generated from the first accelerating structure by solenoid coils covering it.
THPCH172	Present Status of Beam Collimation System of J-PARC RCS	3200
	K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken M. Abe, H. Hanaue, A. Nakamura, Y. Takeuchi VIC International Co., Ltd., Tokyo Y. Hirooka, M. Okazaki Mitsui Engineering & Shipbuilding Co., Ltd., Tokyo
	The precedence manufacture of the two beam collimator was carried out. In these two sets, we tested the heat transfer capacity of cooling fins and remote clamp handling system. The vertical collimator was able to keep temperature under 120 degrees C by the design heat 400W, but in case of the horizontal collimator, it went over 200 degrees C by the design heat 700W. The design was changed towards adding an air duct. About remote clamp handling system, it checked that it could attach by the He leak below 5.*10-10Pa m3/sec as a result of the helium leak examination.
THPCH174	Multipactor Electron Gun with CVD Diamond Cathodes	3203
	J.Y. Zhai, C.-X. Tang, S. Zheng TUB, Beijing
	A Multipactor Electron Gun (MEG) is developed for the high power microwave generation in the Accelerator Lab of Tsinghua University. This paper presents the recent experimental results of the S-band MEG using hydrogen-terminated and CsI-terminated CVD diamond cathodes. The gun design, cathode preparation and high power experiment are described. An electron beam with 5 μs macro-pulse, 10 Hz repetition rate, greater than 900 mA beam current was obtained.calculation and computer simulation. The properties of the secondary electron emission cathodes are also discussed.
THPCH175	Automatic Resonant Excitation Based System for Lorentz Force Compensation for Flash	3206
	P.M. Sekalski, A. Napieralski TUL-DMCS, Lodz S. Simrock DESY, Hamburg
	The cavity is the key element of each linear accelerator used for high-energy physics purpose. The resonant frequency of cavities depends on its shape. Due to the pulse operation, they are deformed by dynamic Lorentz force (LF) caused by accelerating electromechanical field. As a consequence, the cavities are not working on resonance but they are detuned from master oscillator frequency by few hundreds of Hertz depending on accelerating field gradient. The paper presents an automatic control system for LF compensation applied to fast tuning mechanism CTS. The active element is multilayer low-voltage piezoelectric stack (EPCOS). The resonant excitation with adaptive feed forward algorithm is used to drive the actuator. Test performed at FLASH (former name VUV-FEL) on cav5/ACC1 showed that detuning during flat-top period (800us) might remain below 10Hz for accelerating field gradient of 20MV/m.
THPCH177	Design and Construction of the PEFP Timing System for a 20 MeV Proton Beam	3212
	Y.-G. Song, Y.-S. Cho, H.M. Choi, I.-S. Hong KAERI, Daejon K.M. Ha, J.H. Kim PAL, Pohang, Kyungbuk
	The timing system of the PEFP requires synchronization for the accelerator and for the multipurpose beam line. The system is based on an event distribution system that broadcasts the timing information globally to all the equipment. Fast I/O hardware of the timing system is to distribute appropriate timing signals to accelerator systems, including the Injector, RFQ, DTL, and user's facilities. Signals to be distributed include the synchronized pulse triggers and event information of RF system and switching magnet power supplies for the 20MeV proton beam extraction.
THPCH179	High Power Cavity Combiner for RF Amplifiers	3215
	F. Pérez, B. B. Baricevic, D. Einfeld, P. Sanchez ALBA, Bellaterra J.P. Buge, M.L. Langlois, G. Peillex-Delphe TED, Thonon
	A new approach of RF power combination has been developed for the ALBA Storage Ring RF system: a three-port high power Cavity Combiner (CaCo). A prototype has been successfully built and tested in Thales Electron Devices, Thonon, France. The final goal is to combine the power of two 80 kW IOTs at 500 MHz in order to provide a total output power of 160 kW. In this paper, a summary of the analytical and simulation analysis of the expected behaviour is given. In basis of that, the decided geometric constraints and the final design configuration chosen for the prototype production are explained. Low power test results and matching, and finally the high power test performances, are shown. As a conclusion, the RF system of the ALBA Storage Ring will incorporate the CaCo concept to obtain the needed power per cavity from the combination of two IOTs.
THPCH180	Equipment for Tunnel Installation of Main and Insertion LHC Cryo-magnets	3218
	K. Artoos, S. Bartolome-Jimenez, O. Capatina, T. Feniet, J.L. Grenard, M. Guinchard, K. Kershaw CERN, Geneva
	The installation of about 1700 superconducting dipoles and quadrupoles in the Large Hadron Collider (LHC) is now well underway. The transport and installation of the LHC cryo-magnets in the LEP tunnels originally designed for smaller, lighter LEP magnets have required development of completely new handling solutions. The severe space constraints combined with the long, heavy loads have meant that solutions had to be very sophisticated. The paper describes the procedure of the installation of the main cryo-magnets in the arc as well as the more specific insertion cryo-magnets. The logistics for the handling and transport are monitored with tri-axial acceleration monitoring devices that are installed on each cryo-magnet to ensure their mechanical and geometric integrity. These dynamic results are commented. The paper includes conclusions and some lessons learned.
THPCH181	Overview of the Large Hadron Collider Cryo-magnets Logistics	3221
	O. Capatina, K. Artoos, R. Bihery, P. Brunero, J.M. Chevalley, L.P. Dauvergne, T. Feniet, K. Foraz, J. Francey, J.L. Grenard, M. Guinchard, C. Hauviller, K. Kershaw, S. Pelletier, S. Prodon, I. Ruehl, J. Uwumarogie, R. V. Valbuena, G. Vellut, S. Weisz CERN, Geneva
	More than 1700 superconducting cryo-magnets have to be installed in the Large Hadron Collider tunnel. The long, heavy and fragile LHC cryo-magnets are difficult to handle and transport in particular in the LEP tunnel environment originally designed for smaller, lighter LEP magnets. An installation rate of more than 20 cryo-magnets per week is needed to cope with the foreseen LHC installation end date. The paper gives an overview of the transport and installation sequence complexity, from the storage area at the surface to the cryo-magnet final position in the tunnel. The success of this task depends on a series of independent factors that have to be considered at the same time. The equipment needed for the transport and tunnel installation of the LHC cryo-magnets is briefly described. The manpower and equipment organisation as well as the challenges of logistics are then detailed. The paper includes conclusions and some of the lessons learned during the first phase of the LHC cryo-magnets installation.
THPCH182	Control of the Geometrical Conformity of the LHC Installation with a Single Laser Source	3224
	J.-P. Corso, M. Jones, Y. Muttoni CERN, Geneva
	A large and complex accelerator like LHC machine needs to integrate several thousand different components in a relatively limited space. During the installation, those components are installed in successive phases, always aiming to leave the necessary space available for the equipment which will follow. To help ensure the correct conditions for the installation, the survey team uses a laser scanner to measure specific areas and provides this data, merged together in a known reference system, to the integration team who compares the results with the 3D CAD models. This paper describes the tools and software used to rebuild underground zones in the CATIA environment, to check interferences or geometrical non-conformities, as well as the procedures defined to solve the identified problems.
THPCH183	Installation and Quality Assurance of the Interconnections between Cryo-assemblies of the LHC Long Straight Sections	3227
	C. Garion, I. Slits, J.-P.G. Tock CERN, Geneva
	The interconnections between the cryomagnets and cryogenic utilities in the LHC long straight sections constitute the last machine installation activity. They are ensuring continuity of the beam and insulation vacuum systems, cryogenic fluid and electrical circuits and thermal insulation. The assembly is carried out in a constraining tunnel environment with restricted space. Therefore, the assembly sequence has to be well defined, and specific tests have to be performed during the interconnection work to secure the reliability of the system and thus to ensure the global accelerator availability. The LHC has eight long straight insertion zones composed of special cryomagnets involving specific interconnection procedures and QA plans. The aim of this paper is to present the installation and quality assurance procedures implemented for the LHC LSS interconnections. Technologies such as manual and automatic welding and resistive soldering will be described as well as the different quality controls such as visual and radiographic inspection of welds, electrical and leak testing. An evaluation and statistical analysis of the results of the interconnection work will be presented.
THPCH184	Handling and Transport of Oversized Accelerator Components and Physics Detectors	3230
	S. Prodon, C. Bertone, M. Guinchard, P. Minginette CERN, Geneva
	For cost, planning and organisational reasons, it is often decided to install large pre-built accelerators components and physics detectors. As a result, on surface, exceptional transports are required from the construction to the installation sites. Such heavy transports have been numerous during the LHC installation phase. This paper will describe the different types of transport techniques used to fit the particularities of accelerators and detectors components (weight, height, acceleration, planarity) as well as the measurement techniques for monitoring and the logistical aspects (organisation with the police, obstacles on the roads, etc). As far as oversized equipment is concerned, the lowering into the pit is challenging, as well as the transport in tunnel galleries in a very scare space and without handling means attached to the structure like overhead travelling cranes. From the PS accelerator to the LHC, handling systems have been developed at CERN to fit with these particular working conditions. This paper will expose the operating conditions of the main transport equipments used at CERN in PS, SPS and LHC tunnels.
THPCH185	Planning and Logistics Issues Raised by the Individual System Tests during the Installation of the LHC	3233
	S. Weisz, E. Barbero-Soto, K. Foraz, F. Rodriguez-Mateos CERN, Geneva
	The running of individual system tests has to fit within tight constraints of the LHC installation planning and of CERN's accelerator activity in general. For instance, the short circuit tests of the power converters that are performed in situ restrict the possibility to work in neighbouring areas; much in the same way, the cold tests of the cryogenic distribution line involve safety access restrictions that are not compatible with the transport and installation of cryo-magnets or interconnect activities in the sector considered. Still, these individual system tests correspond to milestones that are required to ensure that we can continue with the installation of machine elements. This paper reviews the conditions required to perform the individual system tests and describe how the general LHC installation planning is organised to allocate periods for these tests.
THPCH186	Magnetic Field Measurement and Fine-tuning of Kickers	3236
	T.-C. Fan, C.-H. Chang, C.-S. Fann, C.-S. Hwang, F.-Y. Lin NSRRC, Hsinchu
	We have demonstrated an algorithm which promisingly can tune the pulse shape of current and magnetic field of kicker systems in-situ. This algorithm includes gap shimming of the ferrite magnets to adjust the pulse width of the excitation current and changing the resistance of the secondary coils to modify the pulse curvatures of each kicker. With the empirical formula derived from the systematic measurement on the magnetic field and the pulse current in laboratory, we can reduce the pulse-shape difference among the kicker magnets in the injection section of the storage ring, with no need to do anything on the pulsers and high voltage power suppliers. This approach can efficiently increase the injection efficiency which is demanding in the top-up injection mode adopted by many new facilities of synchrotron radiation.
THPCH187	Analysis and Reduction Electromagnetic Interference to ICTs Caused by Pulsed Power Supply Excitation in NSRRC	3239
	Y.-H. Liu, J.-C. Chang, J.-R. Chen, Y.-C. Lin NSRRC, Hsinchu
	The purpose of this paper is to eliminate the Electromagnetic Interference (EMI) from kicker power supply. Analyses of the EMI source and the propagation path are the beginning missions. The radiated and conducted EMI both affected the Integral Current Transformer (ICT) normal operation because of the space limitation for TLS in NSRRC. The ICT is to measure injection efficiency, thus, ICT located just behind the kickers and using the common girder. The EMI signals therefore are much higher than the electron beam currents, and the integral values of the sensor are not correct. For reducing and eliminating the interference of electromagnetic waves, a hybrid segregation and grounding method was used. The EMI wrapper was enclosed the ICT and its high frequency amplifier separately to prevent the radiated EMI from the space. The grounding paths provided the possible stray current dredge to the ground loop. It reduced the stray current spread to the subsystems next to the kickers. The EMI therefore reduced 99%, and the injection efficiency could be calculated successfully. The elimination of the EMI from kicker itself will be the next step in the future.
THPCH192	Experimental, Test and Research Beamlines at Fermilab	3242
	C. Johnstone Fermilab, Batavia, Illinois
	Three new external beamlines are in operation or under development at Fermilab: 1) the Main Injector Particle Production (MIPP) beamline, 2) the Mucool Test Area (MTA) beamline, and 3) a new MTEST beamline for advanced detector work for high energy experiments and the ILC. The MIPP beamline is a secondary production beamline capable of producing well-characterized beams of protons, pions, and kaons from 5-120 GeV/c using 120 GeV/c protons from the Fermilab Main Injector. The second line is a new primary 400-MeV proton beamline derived from the 400 MeV proton Linac which will provide for precision measurements of Linac beam parameters in addition to a high-intensity primary test beam for development and verification of muon ionization cooling apparatus. A dual mode operation will also provide accurate, dispersion-free measurements of the Fermilab Linac beam properties with potential for diagnostic development. Installation is planned in 2007. Finally, a third beam is also under design to provide secondary beams at ultra-low - high energies, from ~1 GeV/c to 90 GeV/c in addition to a primary 120-GeV proton mode of operation. It is anticipated that this last line will be installed in fall of 2006.
THPCH193	Comparison between H-ion and Heat Cleaning of Cu-metal Cathodes	3245
	D. Dowell, F. King, R.E. Kirby, J.F. Schmerge SLAC, Menlo Park, California
	Understanding the quantum efficiency (qe) of a metal photocathode in an s-band RF gun is important to limit the drive laser energy requirement and provide the best quality electron beam. Systematic measurements of the qe vs. wavelength for varying surface contamination have been performed on copper samples using x-ray photoelectron spectroscopy (XPS). The sample is first cleaned to the theoretical limit of qe using a 1 keV hydrogen ion beam. The H-ion beam cleans an area approximately 1cm in diameter and has no effect on the surface roughness while removing essentially all contaminants and lowering the work function to 4.3eV. The sample is then exposed to atmospheric contaminants (nitrogen and oxygen) and measured again with XPS to determine the degree of contamination and the effect on the qe. The goal is to determine the best procedure for transferring and installing cathodes in an s-band gun. These results and comparison with a heat cleaned cathode are presented.
THPCH194	Investigation of Using Ferroelectric Materials in High Power Fast RF Phase Shifters for RF Vector Modulation	3248
	J.L. Wilson, Y.W. Kang ORNL, Oak Ridge, Tennessee A.E. Fathy University of Tennessee, Knoxville, Tennessee
	A fast ferroelectric phase shifter controlled by an electric field bias is being investigated for high-power RF phase shifters in vector modulation. Such a device could be used in charged particle accelerators, allowing vector control of the RF power delivered to accelerating RF cavities. Bulk ferroelectric materials, particularly those based on barium-strontium titanate (BST) compounds, have shown promise in high-power applications because of their low loss tangent and high dielectric strength. Such materials have already been investigated for use in fast phase shifters at X-Band frequencies. Several different compositions of BST compounds are investigated in phase shifter prototypes at 402.5 MHz and 805 MHz that could be easily adapted for future large-scale accelerator projects. The ratio of barium versus strontium in the composition is varied from sample to sample. This allows an investigation of the tradeoffs involved between dielectric strength, loss tangent, tunability, and relative permittivity. Since ferroelectrics are by nature nonlinear dielectric compounds, preliminary study on the nonlinear propagation effects is conducted through computer simulation. V. P. Yakovlev et al. Fast X-Band Phase Shifter, Advanced Accelerator Concepts: Eleventh Workshop, 2004.
THPCH195	New Developments on Low-loss Ferroelectrics for Accelerator Applications	3251
	A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio A. Dedyk, S.F. Karmanenko Eltech University, St. Petersburg E. Nenasheva Ceramics Ltd., St. Petersburg V.P. Yakovlev Omega-P, Inc., New Haven, Connecticut
	Recent results on development of BST (barium strontium titanium oxide composition) ferroelectric materials are presented to be used as the basis for new advanced technology components suitable for high-gradient accelerators. Ferroelectric materials offer significant benefits for linear collider applications, in particular, for switching and control elements where a very short response time of 10 ns can be potentially achieved. The applications include: fast active X-band and Ka-band high-power ferroelectric switches, high-power X-band, and L-band ferroelectric-based phase-shifters. The recently developed large diameter (11 cm) BST-based ferroelectric rings will be used at high pulse power (tens of megawatts) for the X-band components as well as at high average power (in the range of a few kilowatts) for the L-band phase-shifters, which are suitable for ILC applications.
THPCH196	A Proof-of-Principle Experiment for a High-Power Target System	3254
	H.G. Kirk, V. Samulyak, N. Simos, T. Tsang BNL, Upton, Long Island, New York J.R.J. Bennett CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon T.R. Edgecock CCLRC/RAL, Chilton, Didcot, Oxon I. Efthymiopoulos, A. Fabich, H. Haseroth, F. Haug, J. Lettry CERN, Geneva V.B. Graves, P.T. Spampinato ORNL, Oak Ridge, Tennessee K.T. McDonald PU, Princeton, New Jersey H.J. Park PAL, Pohang, Kyungbuk
	The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field.
THPCH197	Analysis of Availability and Reliability in RHIC Operations	3257
	F.C. Pilat, P. Ingrassia, R.J. Michnoff BNL, Upton, Long Island, New York
	RHIC has been successfully operated for five years as a collider for different species, ranging from heavy ions including gold and copper, to polarized protons. We present a critical analysis of reliability data for RHIC that not only identifies the principal factors limiting availability but also evaluates critical choices at design times and assess their impact on present machine performance. RHIC availability data are compared to similar high-energy colliders and synchrotron light sources. The critical analysis of operations data is the basis for studies and plans to improve RHIC machine availability beyond the 60% typical of high-energy collider.