PAC07 - List of Keywords (pick-up)

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Paper	Title	Other Keywords	Page
MOPAN007	A Non-intercepting Beam Current Monitor for the ISAC-II SC-linac	ion, linac, vacuum, impedance	155
	W. R. Rawnsley R. E. Laxdal, A. K. Mitra TRIUMF, Vancouver
	A personnel protection system will monitor the ion beam current into the experimental hall from the ISAC-II SC-linac. It will use continuous self-test and redundancy and have an accuracy of ±10% from 1 to 200enA. The system, based on an Atlas design, will use capacitive pickups with rf resonators and buffer amplifiers. Ion charge, velocity and bunch width will affect the sensitivity so periodic calibration with dc Faraday cups will be needed. The signal from each 13cm long, 5cm diameter pickup tube will pass through a vacuum feedthrough to a helical resonator. An AD8075 IC with an input impedance of 87kΩ at 35MHz will allow a high coil tap. The ISAC beam, bunched at 11.8MHz, is injected into the ISAC-II SC-linac via a 25m long transfer line. Monitors will be placed in the transfer line and downstream of the linac before the experimental hall. A 35MHz and a 70MHz coil (3 and 6 harmonic) have loaded Q's of 600. A test in the transfer line of the 35MHz coil gave a sensitivity 0.09mV/enA from the unity gain buffer using ²⁰Ne⁺⁵ ions at 1.5MeV/u. The background was equivalent to 1enA. The 70MHz coil gave 0.04mV/enA using ²²Ne⁺⁴ ions. System design and test data will be presented.

MOPAN056	Development of Digital Transverse Bunch-by-Bunch Feedback System of HLS	feedback, kicker, single-bunch, damping	278
	Z. R. Zhou Y. B. Chen, L. J. Huang, B. Sun, J. H. Wang, Y. L. Yang, K. Zheng USTC/NSRL, Hefei, Anhui K. Kobayashi, T. Nakamura JASRI/SPring-8, Hyogo-ken
	Funding: Supported by "National 211 Project" To promote the transverse feedback system of HLS, we develop the transverse digital feedback system. The scheme of HLS digital feedback system is presented in this paper, and the primitive digital feedback experiment we have done in HLS is also included in the paper.

MOPAN066	First Tests of a Precision Beam Phase Measurement System in CTF3	linac, luminosity, extraction, collider	302
	A. Andersson J. P.H. Sladen CERN, Geneva
	Funding: This work is supported by the Commission of the European Communities under the 6th Framework Programme -Structuring the European Research Area-, contract number RIDS-011899. High precision beam phase measurements will be vital for synchronization of main and drive beams in CLIC. Development work is underway with the aim to demonstrate 0.1 degree resolution for a wideband 30GHz measurement. In order to be able to test this with a beam exhibiting much higher phase jitter, two prototypes have been built so that the difference in their outputs can be measured. Results of measurements made with bunch trains in CTF3 are presented.

MOPAS080	A Digital Ring Transverse Feedback Low-Level RF Control System	feedback, damping, controls, simulation	617
	A. K. Polisetti S. Assadi, C. Deibele, J. C. Patterson ORNL, Oak Ridge, Tennessee R. C. McCrady LANL, Los Alamos, New Mexico M. J. Schulte UW-Madison, Madison, Wisconsin
	A digital wide-band system for damping ring instabilities in an accelerator is presented. With increased beam intensity, the losses of an accumulator ring tend to increase due to the onset of various instabilities in the beam. An analog feedback damper system has been implemented at Los Alamos National Laboratory. This analog system, while functional, has certain limitations and a lack of programmability, which can be overcome by a digital solution. A digital feedback damper system is being designed through a collaborative effort by researchers at Oakridge National Laboratory, Los Alamos National Laboratory, and the University of Wisconsin. This system, which includes analog-to-digital converters, field programmable gate arrays and digital-to-analog converters can equalize errors inherent to analog systems, such as dispersion due to amplifiers/cables, gain mismatches, and timing adjustments. The digital system features programmable gains and delays, and programmable equalizers that are implemented using digital FIR and comb filters. The flexibility of the digital system allows it to be customized to implement different configurations and extended to address other diagnostic problems.

MOPAS101	Characterization of the RF System of NSLS X-ray Ring	electron, synchrotron, storage-ring, controls	661
	I. Pinayev
	The proper phasing is required for a storage ring with multiple RF cavities. In this paper we present method for simultaneous measurement of the accelerating voltage and relative phase for individual cavity at operational conditions. Theory and experimental results for NSLS X-ray synchrotron are presented.

MOPAS103	Optical Parametric Amplifier Test for Optical Stochastic Cooling of RHIC	radiation, laser, undulator, ion	667
	P. I. Pavlishin M. Babzien, I. Pogorelsky, D. Stolyarov, V. Yakimenko BNL, Upton, Long Island, New York M. S. Zolotorev LBNL, Berkeley, California
	Funding: Work supported by US Department of Energy contract DE-AC02-98CH10886 Optical stochastic cooling for the Relativistic Heavy Ion Collider (RHIC) based on optical parametric amplification was proposed by M. Babzien et al., Phys. Rev. ST Accel. Beams v.7, 012801, (2004). According to this proposal a CdGeAs2 nonlinear crystal is used as an active medium for the optical parametric amplifier because of extremely large nonlinear coefficient, wide transparency range, and possibility to be phase matched over the required spectral range. We discuss experimental results of the parametric amplifier gain and coherency for the conditions applicable to optical stochastic cooling for RHIC.

TUYC01	Studies of the Pulse Line Ion Accelerator	ion, acceleration, vacuum, induction	852
	W. L. Waldron R. J. Briggs SAIC, Alamo, California A. Friedman LLNL, Livermore, California E. Henestroza, L. R. Reginato LBNL, Berkeley, California
	Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U. S. Department of Energy under Contracts No. DE-AC02-05CH11231 and W-7405-Eng-48. The Pulse Line Ion Accelerator concept was motivated by the need for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied to one end of a helical pulse line creates a traveling wave that accelerates and axially confines the heavy ion beam pulse. The concept has been demonstrated with ion beams at modest acceleration gradients. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/m acceleration gradients. This method has the potential to reduce the length of an equivalent induction accelerator by a factor of 6-10 while simplifying the pulsed power systems. The performance of prototype hardware has been limited by high voltage flashover across the vacuum insulator. Bench tests and analysis have led to significantly improved flashover thresholds. Further studies using a variety of experimental configurations are planned.
	Slides

TUPAN027	A New Complementary-Scan Technique for Precise Measurements of Resonance Parameters in Antiproton-Proton Annihilations	resonance, antiproton, background, luminosity	1448
	G. Stancari
	A new technique for precision measurements of resonance widths in antiproton-proton annihilations is presented. It is based on the analysis of excitation curves obtained by scanning the resonance twice, at constant orbit and at constant magnetic bend field, in an antiproton storage ring. The technique relies on precise revolution-frequency and orbit-length measurements, while making the results almost independent of the machine's phase-slip factor. The uncertainty is dominated by event statistics. The technique was recently applied by Fermilab Experiment E835 at the Antiproton Accumulator to obtain the most precise measurements to date of the total and partial widths of the psi(2S) charmonium meson. Future applications may include the PANDA experiment at the FAIR facility in Darmstadt. On behalf of the Fermilab E835 Collaboration

TUPAN058	High Power Conditioning of the DTL for J-PARC	vacuum, klystron, linac, acceleration	1517
	T. Ito H. Ao JAEA/LINAC, Ibaraki-ken H. Asano, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken T. Kato, F. Naito, E. Takasaki, H. Tanaka KEK, Ibaraki
	For the J-PARC, DTL (Drift Tube Linac) is used to accelerate an H^- ion beam from 3MeV to 50MeV. The DTL consists of 3 tanks and the all tanks were installed in the accelerator tunnel for J-PARC. After the installation, the high power conditioning has been started in Oct. 2006. The required rf power levels for beam acceleration are about 1.08MW, 1.2MW and 1.03MW (the pulse length is 600μsec and the pulse repetition is 25Hz) for the 1st, 2nd and 3rd tanks, respectively. As a result of the conditioning, we have been achieved that the rf power levels are about 1.3MW, 1.45MW and 1.23MW of 1.2 times required power levels (the pulse length is 650μsec and the pulse repetition is 25Hz). In this paper, the results of the high power conditioning of the DTL tanks are described.

TUPAN078	Design and Fabrication of the PEFP DTL II	vacuum, proton, linac, alignment	1553
	Y.-H. Kim Y.-S. Cho, J.-H. Jang KAERI, Daejon
	Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government The PEFP DTL II which accelerates a proton beam from the energy of 20MeV Beam to 100MeV is now under fabrication. The DTL II which has some similar specifications with the DTL I which accelerates the proton beam to the energy of 20MeV is made of seamless carbon steel with Cu electroplating inside. The DTL tank is divided into 3 sections whose length is about 2.2m. We verified the mechanical and thermal stability using ANSYS code, and we established the fabrication process of the drift tube. The DTL II is now being fabricated.

TUPAN089	The LHC Beampipe Waveguide Mode Reflectometer	cryogenics, quadrupole, controls, scattering	1583
	F. Caspers P. Borowiec, T. Kroyer, Z. Sulek, L. R. Williams CERN, Geneva
	Several specially developed waveguide-mode reflectometers for obstacle detection in the LHC magnet beampipes have been intensively used for more than 18 months. This "Assembly" version is based on the synthetic pulse method using a modern vector network analyzer. It has mode selective excitation couplers and uses a specially developed waveguide mode dispersion compensation algorithm with external software. In addition there is a similar "in situ" version of the reflectometer which uses permanently installed microwave couplers at the end of each of the nearly 3 km long LHC arcs. A considerable number of unexpected objects have been found in the beampipes and subsequently removed. Operational statistics and lessons learned are presented and the overall performance is discussed.

WEXC01	Experimental Tests of a Prototype System for Active Damping of the E-P Instability at the LANL PSR	feedback, proton, damping, electron	1991
	C. Deibele S. Assadi, V. V. Danilov, S. Henderson, M. A. Plum, A. K. Polisetti ORNL, Oak Ridge, Tennessee J. M. Byrd LBNL, Berkeley, California J. D. Gilpatrick, R. C. McCrady, J. F. Power, T. Zaugg LANL, Los Alamos, New Mexico S.-Y. Lee IUCF, Bloomington, Indiana M. T.F. Pivi SLAC, Menlo Park, California M. J. Schulte, Z. P. Xie UW-Madison, Madison, Wisconsin
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725. A prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability has been developed and successfully tested at the Los Alamos Proton Storage Ring (PSR). This talk describes the system configuration, results of several experimental tests and studies of system optimization along with studies of the factors limiting its performance.
	Slides

WEYC02	Stochastic Cooling of High-Energy Bunched Beams	simulation, kicker, emittance, ion	2014
	M. Blaskiewicz J. M. Brennan, F. Severino BNL, Upton, Long Island, New York
	Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH1-886 Stochastic cooling of 100 GeV/nucleon bunched beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). The physics and technology of the longitudinal cooling system are discussed, and plans for a transverse cooling system are outlined.
	Slides

WEPMN027	Construction of the Baseline SC Cavity System for STF at KEK	coupling, radiation, controls, linear-collider	2107
	E. Kako H. Hayano, S. Noguchi, T. Shishido, K. Watanabe, Y. Yamamoto KEK, Ibaraki
	Construction of STF (Superconducting RF Test Facility) is being carried out at KEK. Four-cavity system including 9-cell baseline cavities (TESLA-type), input couplers and frequency tuners has been developed and will be installed in a 6 m cryomodule. The peculiarity of the STF baseline cavity system is a very stiff design in a jacket and tuner system, which can relax the effect of Lorentz detuning in a pulsed operation. Performance tests of four 9-cell cavities have been carried out repeatedly in a vertical cryostat, and the attained accelerating gradients reached to about 20 MV/m with no field emission in each cavity. High power input couplers with two planar rf windows were fabricated, and the rf processing test with a pulsed klystron was successfully carried out up to 1.0 MW with 1.5 msec and 5 Hz without any troubles. Assembly of the cryomodule including one 9-cell baseline cavity had completed (STF phase 0.5), and the first cool-down test is scheduled in March, 2007.

WEPMN058	Analog Components Configuration and Test results for PEFP LLRF system	controls, feedback, rfq, proton	2170
	K. T. Seol Y.-S. Cho, D. I. Kim, H. S. Kim, H.-J. Kwon KAERI, Daejon
	Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government. The PEFP LLRF system for the 3MeV RFQ and 20MeV DTL has been developed. The stability of ±1% in the amplitude and ±1˚ in the phase is required. Therefore, the drift of the analog components should be low to satisfy the requirement. Analog chassis as a prototype of LLRF system is configured and tested. RF components including an IQ modulator, an RF switch, a mixer, phase comparators, RF splitters, RF filters and trip circuit for high VSWR are installed in this chassis. This performs the shift of RF amplitude and phase from IQ signal, down-conversion to 10MHz IF signal, interlock for arc and high VSWR, and RF/clock distribution. The amplitude and phase stability of each component are measured to check the effect on the whole system performance. The detailed configuration and test results are presented.

WEPMN091	Beam Test of a Grid-less Multi-Harmonic Buncher	ion, bunching, linac, simulation	2242
	P. N. Ostroumov V. N. Aseev, A. Barcikowski, E. Clifft, R. C. Pardo, M. Sengupta, S. I. Sharamentov ANL, Argonne, Illinois
	Funding: This work was supported by the U. S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357. The Argonne Tandem Linear Accelerator System (ATLAS) is the first superconducting heavy-ion linac in the world. Currently ATLAS is being upgraded with the Californium Rare Ion Breeder Upgrade (CARIBU). The latter is a funded project to expand the range of short-lived, neutron-rich rare isotope beams available for nuclear physics research at ATLAS. To avoid beam losses associated with the existing gridded multi-harmonic buncher, we have developed and built a grid-less four-harmonic buncher with fundamental frequency of 12.125 MHz. In this paper, we are going to report the ATLAS beam performance with the new buncher.

WEPMN100	RF Design and Processing of a Power Coupler for Third Harmonic Superconducting Cavities	vacuum, klystron, electron, simulation	2265
	J. Li E. R. Harms, T. Kubicki, D. J. Nicklaus, D. R. Olis, P. S. Prieto, J. Reid, N. Solyak Fermilab, Batavia, Illinois T. Wong Illinois Institute of Technology, Chicago, Illinois
	Funding: U. S. Department of Energy The FLASH user facility providing free electron laser radiation is built based on the TTF project at DESY. Fermilab has the responsibility for the design and processing of a third harmonic, 3.9 GHz, superconducting cavity which is powered via a coaxial power coupler. Six power couplers have been manufactured at CPI after successful design of the power coupler including RF simulation, multipacting calculation, and thermal analysis. The power couplers are being tested and processed with high pulsed power in an elaborate test stand at Fermilab now. This paper presents the RF design and processing work of the power coupler.

WEPMN107	RF and Data Acquisition Systems for Fermilab's ILC SRF Cavity Vertical Test Stand	controls, radiation, instrumentation, shielding	2286
	J. P. Ozelis C. Grenoble, T. Powers Jefferson Lab, Newport News, Virginia R. Nehring Fermilab, Batavia, Illinois
	Funding: Operated by Universities Research Association, Inc. for the U. S. Department of Energy under contract DE-AC02-76CH03000 Fermilab is developing a facility for vertical testing of SRF cavities as part of a program to improve cavity performance reproducibility for the ILC. The RF system for this facility, using the classic combination of oscillator, phase detector/mixer, and loop amplifier to detect the resonant cavity frequency and lock onto the cavity, is based on the proven production cavity test systems used at Jefferson Lab for CEBAF and SNS cavity testing. The design approach is modular in nature, using commercial-off-the-shelf (COTS) components. This yields a system that can be easily debugged and modified, and with ready availability of spares. Data acquisition and control is provided by a PXI-based hardware platform in conjunction with software developed in the LabView programming environment. This software provides for amplitude and phase adjustment of incident RF power, and measures all relevant cavity power levels, cavity thermal environment parameters, as well as field emission-produced radiation. It also calculates the various cavity performance parameters and their associated errors. Performance during system commissioning and initial cavity tests will be presented.

WEPMN111	3.9 GHz Superconducting Accelerating 9-cell Cavity Vertical Test Results	simulation, resonance, electromagnetic-fields, vacuum	2295
	T. N. Khabiboulline C. A. Cooper, N. Dhanaraj, H. Edwards, M. Foley, E. R. Harms, D. V. Mitchell, A. M. Rowe, N. Solyak Fermilab, Batavia, Illinois W.-D. Moller DESY, Hamburg
	The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve beam performances of the FLASH (TTF/DESY) facility. In the frame of collaboration Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first results of vertical tests of 9-cell Nb cavities didn?t reached the designed accelerating gradient. The main problem is multipactoring in HOM couplers, which leads to quenching and overheating of the HOM couplers. New HOM couplers with improved design integarated to next 9-cell cavities. In this paper we present all results of vertical tests.

WEPMS009	Results on 9-cell ILC and 9-cell Re-Entrant Cavities	cathode, target, controls	2343
	H. Padamsee B. Ashmanskas Fermilab, Batavia, Illinois M. D. Cole, A. J. Favale, J. Rathke AES, Princeton, New Jersey A. C. Crawford CLASSE, Ithaca
	Funding: DOE We have recently upgraded our chemical treatment, high pressure rinsing systems and low temperature RF testing system to prepare and test 9-cell cavities for ILC. After removal of 120 um by BCP we reached 26 MV/m accelerating field limited by the high-field Q-slope. There was no quench and no field emission, showing that our facilities are well qualified. We have also extended our vertical electropolishing system to 9-cell cavities. Previously we have successfully used vertical electropolishing for one-cell cavities of the re-entrant shape to reach 47 MV/m accelerating. Test results on 9-cell electropolished cavities will be presented. AES has manufactured the first 9-cell cavity with re-entrant cell shapes. The surface magnetic field is 10% lower than for the standard TESLA-shape cavity. Half-cells were electropolished 100 um before welding. We will present results on the first tests of the 9-cell re-entrant cavity.

WEPMS010	Surface Studies of Contaminants Generated During Electropolishing	cathode, power-supply, electron	2346
	A. V. Morgan H. Padamsee Cornell University, Ithaca, New York A. Romanenko, A. J. Windsor CLASSE, Ithaca
	Funding: NSF Electropolishing is now the preferred method for chemical treatment of niobium cavity surfaces. It provides a very smooth surface and after baking accelerating fields between 35 - 40 MV/m. However the reproducibility of performance needs to be improved substantially. Some of the leading causes are related to contaminant residues after electropolishing, these include sulphur particles, niobium pentoxide particles and traces of aluminum from reaction between the aluminum cathode and the acid electrolyte. We have carried out studies to enhance the deposition of such particles so that we can isolate and study the residues. We will present analysis of these studies using optical microscopy, SEM, and Auger. In at attempt to dissolve these contaminants, we have also conducted studies on the effectiveness of various rinsing agents, such as degreasing agents, dilute HF, hydrogen peroxide.

WEPMS017	High-Power Coupler Component Test Stand Status and Results	electron, vacuum, simulation, space-charge	2367
	B. Rusnak C. Adolphsen, G. B. Bowden, L. Ge, R. K. Jobe, Z. Li, B. D. McKee, C. D. Nantista, J. Tice, F. Wang SLAC, Menlo Park, California R. Swent Stanford University, Stanford, Califormia
	Funding: This work was performed under the auspices of the U. S. DOE by the University of California, LLNL under Contract No. W-7405-Eng-48. SLAC Work supported under Contract No. W-7405-Eng-48. Fundamental power couplers for superconducting accelerator applications like the ILC are complicated RF transmission line assemblies due to their having to simultaneously accommodate demanding RF power, cryogenic, and cleanliness constraints. When these couplers are RF conditioned, the observed response is an aggregate of all the parts of the coupler and the specific features that dominate the conditioning response are unknown. To better understand and characterize RF conditioning phenomena toward improving performance and reducing conditioning time, a high-power coupler component test stand has been built at SLAC. Operating at 1.3 GHz, this test stand was designed to measure the conditioning behavior of select components of the TTFIII coupler independently, including outer-conductor bellows, diameter changes, copper plating and surface preparations, and cold window geometries and coatings. A description of the test stand, the measurement approach, and a summary of the results obtained are presented.

WEPMS021	RF-loss Measurements in an Open Coaxial Resonator for Characterization of Copper Plating	simulation, coupling, cryogenics	2376
	F. L. Krawczyk G. O. Bolme, W. L. Clark, J. P. Kelley, F. A. Martinez, D. C. Nguyen, K. A. Young LANL, Los Alamos, New Mexico J. Rathke, D. L. Schrage, T. Schultheiss, L. M. Young AES, Medford, NY
	Funding: Work supported by the Office of Naval Research and the High-Energy Laser Joint Technology Office. An experiment has been conducted to measure small differences in cavity Q caused by various cavity surface treatments. A requirement of the experiment was that it show little sensitivity to the reassembly with various test pieces. We chose a coaxial half-wave resonator, with an outer conductor extending significantly beyond the length of the inner conductor. The outer conductor acts as a cut-off tube, eliminating the need for electric termination and thus any RF-contacts that can influence the Q-measurements. The experiment is aimed at qualifying the performance of cyanide-copper plated GlidCop in comparison with that of a machined GlidCop surface. To maximize the sensitivity of the measurement we use a fixed outer conductor made of annealed OFE copper and only replace the inner conductor, which is mounted on a low-loss Teflon pedestal located in the low electric field region. The Q-values of machined GlidCop and cyanide-copper plated GlidCop inner conductors are measured against the reference Q of the annealed OFE co-axial cavity. This simple configuration allows a statistically significant number of repetitions of measurements and should provide accurate comparative measurements.

WEPMS041	Multipacting Simulations of TTF-III Coupler Components	simulation, electron, vacuum, linac	2436
	L. Ge C. Adolphsen, K. Ko, L. Lee, Z. Li, C.-K. Ng, G. L. Schussman, F. Wang SLAC, Menlo Park, California B. Rusnak LLNL, Livermore, California
	Funding: This work was supported by US DOE contract No. DE-AC02-76SF00515. This work was performed under the auspices of the US DOE by the University of California, LLNL under Contract No. W-7405-Eng-48. The TTF-III coupler adopted for the ILC baseline cavity design has shown a tendency to have long initial high power processing times. A possible cause for the long processing times is believed to be multipacting in various regions of the coupler. To understand performance limitations during high power processing, SLAC has built a flexible high-power coupler test stand. The plan is to test individual sections of the coupler, which includes the cold and warm coaxes, the cold and warm bellows, and the cold window, using the test stand to identify problematic regions. To provide insights for the high power test, detailed numerical simulations of multipacting for these sections will be performed using the 3D multipacting code Track3P. The simulation results will be compared with measurement data.

WEPMS048	Modelling Imperfection Effects on Dipole Modes in TESLA Cavity	dipole, damping, coupling, polarization	2454
	L. Xiao C. Adolphsen, V. Akcelik, A. C. Kabel, K. Ko, L. Lee, Z. Li, C.-K. Ng SLAC, Menlo Park, California
	Funding: Work supported by DOE contract DE-AC02-76SF00515 The actual cell shape of the TESLA cavities differ from the ideal due to fabrication errors, the addition of stiffening rings and the frequency tuning process. Cavity imperfection shift the dipole mode frequencies and alter the Qext's from those computed for the idea cavity. A Qext increase could be problematic if its value exceeds the limit required for ILC beam stability. To study these effects, a cavity imperfection model was established using a mesh distortion method. The eigensolver Omega3P was then used to find the critical dimensions that contribute to the Qext spread and frequency shift by comparing predictions to TESLA cavity measurement data. Using the imperfection parameters obtained from these studies, artificial imperfection models were generated and the resulting wakefields were used as input to the beam tracking code Lucretia to study the effect on beam emittance. In this paper, we present the results of these studies and suggest tolerances for the cavity dimensions.

WEPMS050	HOM and LOM Coupler Optimizations for the ILC Crab Cavity	damping, dipole, coupling, simulation	2457
	L. Xiao L. Bellantoni Fermilab, Batavia, Illinois G. Burt Cockcroft Institute, Lancaster University, Lancaster P. Goudket, P. A. McIntosh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire K. Ko, Z. Li, C.-K. Ng, G. L. Schussman, A. Seryi, R. Uplenchwar SLAC, Menlo Park, California
	Funding: Work supported by DOE contract DE-AC02-76SF00515 The FNAL 9-cell 3.9GHz deflecting cavity designed for the CKM experiment was chosen as the baseline design for the ILC BDS crab cavity. Effective damping is required for the lower-order TM01 modes (LOM), the same-order TM11 modes (SOM) as well as the HOM modes to minimize the beam loading and beam centroid steering due to wakefields. Simulation results of the original CKM design using the eigensolver Omega3P showed that both the notch filters of the HOM/LOM couplers are very sensitive to the notch gap, and the damping of the unwanted modes is suboptimal for the ILC. To meet the ILC requirements, the couplers were redesigned to improve the damping and tuning sensitivity. With the new design, the damping of the LOM/SOM/HOM modes is significantly improved, the sensitivity of the notch filter for the HOM coupler is reduced by one order of magnitude and appears mechanically feasible, and the LOM coupler is simplified by aligning it on the same plane as the SOM coupler and by eliminating the notch filter. In this paper, we will present the coupler optimization and tolerance studies for the crab cavity.

WEPMS055	SQUID-based Nondestructive Testing Instrument of Dished Niobium Sheets for SRF Cavities	superconducting-RF, controls, superconductivity, micro-particles	2469
	Q. S. Shu I. Ben-Zvi BNL, Upton, Long Island, New York G. Cheng, I. M. Phipps, J. T. Susta AMAC, Newport News, Virginia P. Kneisel, G. Myneni Jefferson Lab, Newport News, Virginia J. Mast, R. Selim CNU, Newport News
	Funding: Acknowledgment: This work is supported by DOE grant DE-FG02-05ER84241 Currently available technology can only inspect flat sheets and allow the elimination of defective flat sheets before the expensive forming and machining of the SRF cavity half-cells, but it does not eliminate the problem of remaining or uncovered surface impurities after partial chemical etching of the half-cells, nor does it detect any defects that may have been added during the fabrication of the half-cells. AMAC has developed a SQUID scanning system based on eddy current technique that allows the scanning of curved Nb samples that are welded to make superconducting RF cavity half-cells. AMAC SQUID scanning system successfully located the defects (Ta macro particles about 100 mm diameter) in a flat Nb sample (top side) and was able to also locate the defects in a cylindrical surface sample (top side). It is more significant that the system successfully located the defects on the backside of the flat sample and curved sample or 3-mm from the top surface. The 3-D SQUID-based Nondestructive instrument will be further optimized and improved in making SRF cavities and allow inspection and detection during cavity manufacturing for achieving highest accelarating fields.

THXC01	LHC Beam Instrumentation	coupling, beam-losses, feedback, synchrotron	2630
	O. R. Jones
	The LHC will have very tight tolerances on all beam parameters. Their precise measurement is therefore very important for controlling and understanding the machine. With over two orders of magnitude higher stored beam energy than previous colliders, machine protection is also an issue, with any beam losses having to be closely monitored. This presentation will aim to give an overview of the beam instrumentation foreseen for the LHC together with the requirements for initial and nominal operation. A summary of the main systems will be followed by a discussion of areas where there have been recent advances, such as in the measurement of tune, chromaticity and coupling.
	Slides

THOBC01	Status of Various SNS Diagnostic Systems	target, beam-losses, diagnostics, instrumentation	2658
	W. Blokland J. G. Patton, T. A. Pelaia, T. R. Pennisi, J. D. Purcell, M. Sundaram ORNL, Oak Ridge, Tennessee
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725 The Spallation Neutron Source (SNS) accelerator systems are ramping up to deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. Enhancements or additions have been made to several diagnostics instruments to support the ramp up in intensity, improve reliability, and/or add functionality. The Beam Current Monitors now support increased rep rates, the Harp system now includes charge density calculations for the target, and a new system has been created to collect data for the beam accounting and present the data over the web and to the operator consoles. Many of the instruments are PC-based and a way to manage their instrument configuration files through the Oracle database has been implemented. A new version for the wire scanner software has been developed and is under test. This paper also includes data from the various instruments.
	Slides

THPAN028	HESR Lattice with Non-similar Arcs for the Stochastic Cooling	lattice, quadrupole, kicker, dynamic-aperture	3289
	Y. Senichev
	The advanced HESR lattice with two arcs having the identical layout and the different slip factors are developed. The conception of arcs with three families of quadrupole allows easy adjusting the imaginary transition energy in one arc and the real transition energy in another arc with the absolute value close to the beam energy in whole required region from 3.0 GeV to 14 GeV. The arcs have the special feature, when the high order non-linearities are fully compensated inside of each arc, and therefore the dynamic aperture of the whole machine is conserved. We consider and compare two lattices with the same absolute value of transition energy: the current lattice with the negative momentum compaction factor in both arcs and the lattice having the negative and positive momentum compaction factors in different arcs correspondingly. Simultaneously we analyzed the 4 and 6 fold symmetry arcs machine. It allows making the conclusion that the 4 fold symmetry lattice is more suitable to get the required slip factors. At the lowest energy 3 GeV, the absolute value of slip factor in the imaginary and the real arc is related as ~0.09/0.02 correspondingly. For the higher beam energy this ratio is much bigger.

THPAN048	Numerical Solver with CIP Method for Fokker Planck Equation of Stochastic Cooling	simulation, kicker, feedback, impedance	3336
	T. Kikuchi T. Katayama CNS, Saitama S. Kawata Utsunomiya University, Utsunomiya
	A Fokker Planck equation for a Stochastic cooling* is solved by using the CIP method*. The Fokker Planck equation can be described in a convection-diffusion equation as a function of time and energy. The equation is a non linear form and the evolution of the distribution function should be numerically solved. The CIP method, which is an effective scheme to solve the convection term numerically, is applied to the Fokker Planck equation of the Stochastic cooling. By using the CIP method for the numerical solver, we can effectively calculate the time-dependent Fokker Planck equation in more few computational costs. The developed numerical solver can give us the energy spectrum of the particle distribution during the beam cooling. The simulation results show the good agreements compared with the experimental results. S. Van der Meer, CERN/PS/AA/78-22, 1978.** T. Yabe and T. Aoki, Comp. Phys. Commun. 66 (1991) 219.

THPAN059	Proposal for an Enhanced Optical Cooling System Test in an Electron Storage Ring	electron, undulator, kicker, storage-ring	3363
	E. G. Bessonov M. V. Gorbunkov LPI, Moscow A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We are proposing to check experimentally the new idea of Enhanced Optical Cooling (EOC) in an electron storage ring. The experiment will confirm new fundamental processes in beam physics and demonstrate new unique possibilities in cooling technique. It will open important applications of EOC in nuclear physics, elementary particle physics and in light sources (LS) based on high brightness electron, proton, and ion beams.

FRPMN017	Beam Position Monitor Calibration at the FLASH Linac at DESY	undulator, electron, free-electron-laser, laser	3937
	N. Baboi P. Castro, O. Hensler, J. Lund-Nielsen, D. Noelle, L. M. Petrosyan, E. Prat, T. Traber DESY, Hamburg M. Krasilnikov, W. Riesch DESY Zeuthen, Zeuthen
	In the FLASH (Free electron LASer in Hamburg) facility at DESY more than 60 beam position monitors (BPM) with single bunch resolution are currently installed, and more are planned for future installation. Their calibration has been initially made by measuring each electronics board in the RF laboratory. However the ultimate calibration of each monitor is made by measuring its response to beam movement. This is a time-consuming procedure depending on the availability and accuracy of other components of the machine such as corrector magnets. On the other hand it has the advantage of getting in one measurement the answer of the monitor with all its components and of being independent of the monitor type. The calibration procedure and particularities for various types of BPMs in various parts of the linac will be discussed. A procedure based on the response matrices is also now under study. This would significantly speed up the calibration procedure, which is particularly important in larger accelerators such as the European XFEL (X-ray Free Electron Laser), to be built at DESY.

FRPMN031	Commissioning and Status of New BPM Electronics for COD Measurement at the SPring-8 Storage Ring	storage-ring, controls, injection, target	3997
	T. Fujita S. Sasaki, M. Shoji, T. Takashima JASRI/SPring-8, Hyogo-ken
	At SPring-8 storage ring, a signal processing circuit for closed orbit measurement and a part of its control system were replaced during summer shutdown period of 2006. In the new circuit, one of four beam signals at the frequency of 508.58 MHz, which is the acceleration frequency of the SPring-8, is selected by a multiplexer and down-converted to IF frequency. The IF signal is sampled by 2 MSPS 16-bit ADC and detected with DSP. On the DSP, spurious frequencies are eliminated by digital filter and effective band-width can be changed by averaging. During the commissioning of the new circuit after the summer shutdown, DSP parameters such as number of averaging were decided to measure beam positions at all BPMs in 3 seconds, although the new circuit was designed with a target repetition of a few 10 Hz or around 100 Hz with resolution of sub-microns. With the DSP parameters, position resolution of less than 0.5 micron is achieved. In this paper, we also describe long term stability, current dependence and beam filling pattern dependence of the new circuit compared with the old one in addition to the position resolution and measurement repetition.

FRPMN043	Measurement of Beam Position Monitor Using HOM Couplers of Superconducting Cavities	linac, dipole, electron, monitoring	4060
	M. Sawamura
	The offset beam from the axis induces the HOMs in the cavities. These HOMs in superconducting cavities are usually damped by HOM couplers to suppress the beam instability. The induced HOM power is proportional to the beam offset and can be used to measure the beam position inside the cavity. The shifter magnet is installed to the JAEA superconducting ERL-FEL to vary the beam position. The HOM power from the HOM coupler with various beam position is measured. The result of the beam test is presented.

FRPMN045	Beam Position Monitor and its Calibration in J-PARC LINAC	linac, monitoring, quadrupole, background	4072
	S. Sato H. Akikawa, Z. Igarashi, N. Kamikubota, S. Lee KEK, Ibaraki M. Ikegami JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken H. Sako, G. B. Shen JAEA, Ibaraki-ken T. Tomisawa, A. Ueno JAEA/LINAC, Ibaraki-ken
	The beam commissioning of J-PARC linac has been started in November 2006. Beam Position Monitors (BPMs) which have been calibrated on the bench setup with a scanning wire, utilize beam based calibration to relate the BPM center and the center of Q magnet. In this presentation, detail of installed BPM and the calibration methods are described.

FRPMN051	Design of S-band Cavity BPM for HLS	monitoring, resonance, electromagnetic-fields, gun	4102
	Q. Luo H. He, P. Li, P. Lu, B. Sun, J. H. Wang USTC/NSRL, Hefei, Anhui
	Funding: Supported by 985 Project of USTC 173123200402002 For the development of accelerators we require increasingly precise control of beam position. Cavity BPMs promise a much higher position resolution compared to other BPM types and manufacture of cavity BPMs is in general less complicated. The cavity BPM operating at S-band for HLS (Hefei Light Source) was designed. It consists of two cavities: a position cavity tuned to TM110 mode and a reference cavity tuned to TM010 mode. To suppress the monopole modes we use waveguides as pickups. Superheterodyne receivers are used in electronics for many cavity BPMs while we decide to use chip AD8302 produced by Analog Devices to process the signals. To simulate and calculate the electromagnetic field we use MAFIA.

FRPMN068	The 4.8 GHz LHC Schottky Pick-up System	impedance, emittance, single-bunch, instrumentation	4174
	F. Caspers T. W. Hamerla, A. Jansson, J. R. Misek, R. J. Pasquinelli, P. C. Seifrid, D. Sun, D. G. Tinsley Fermilab, Batavia, Illinois J. M. Jimenez, O. R. Jones, T. Kroyer, VC. Vuitton CERN, Geneva
	Funding: LARP The LHC Schottky observation system is based on traveling wave type high sensitivity pickup structures operating at 4.8 GHz. The choice of the structure and operating frequency is driven by the demanding LHC impedance requirements, where very low impedance is required below 2 GHz, and good sensitivity at the selected band at 4.8 GHz. A sophisticated filtering and triple down-mixing signal processing chain has been designed and implemented in order to achieve the specified 100 dB instantaneous dynamic range without range switching. Detailed design aspects for the complete systems and test results without beam are presented and discussed.

FRPMN073	The FPGA-based Continuous FFT Tune Measurement System for the LHC and its Test at the CERN SPS	target, controls, betatron, extraction	4204
	A. Boccardi M. Gasior, O. R. Jones, K. K. Kasinski, R. J. Steinhagen CERN, Geneva
	A base band tune (BBQ) measurement system has been developed at CERN. This system is based on a high-sensitivity direct-diode detection technique followed by a high resolution FFT algorithm implemented in an FPGA. The system allows acquisition of continuous real-time spectra with 32-bit resolution, while a digital frequency synthesiser (DFS) can provide an acquisition synchronised chirp excitation. All the implemented algorithms support dynamic reconfiguration of processing and excitation parameters. Results from both laboratory measurements and tests performed with beam at the CERN SPS are presented.

FRPMS004	Geometrical Interpretation of Nonlinearities from a Cylindrical Pick-up	simulation	3862
	R. Miyamoto A. Jansson, M. J. Syphers Fermilab, Batavia, Illinois S. E. Kopp The University of Texas at Austin, Austin, Texas
	In many accelerators, cylindrical pick-ups are used to measure transverse beam position. Although theoretically signals from these pick-ups are related to infinite power series of the beam position, in practice only finite number of terms are considered. Hence, the position measurements degrade when the beam position is far from the center of the pick-up. This paper shows that the power series of the beam position signal actually converges into a compact form with simple geometrical interpretation. It is then proven that with help of these geometrical relations the beam position can be expressed as a compact function of pick-up signals which includes infinite order of nonlinearities. The paper is concluded with a simple test of nonlinearities in signals using pick-ups of the Tevatron and numerical simulations to suggest a possible practical usage of this infinite order expression.

FRPMS007	Status of the FNAL Digital Tune Monitor	proton, antiproton, betatron, collider	3877
	J.-P. Carneiro V. Kamerdzhiev, A. Semenov, R. C. Webber Fermilab, Batavia, Illinois
	We have implemented a real-time method for betatron tune measurements from each bunch at Tevatron based on 16bit 100MHz ADC. To increase the betatron signal level from pick-up we have used a modified version Direct Diode Detection method combined with fast FPGA algorithm and 14 bit DAC for suppression of low frequency beam motion and noise background before final amplifying stage. A descritpion of this devise will be presented in the paper together with first results.

FRPMS013	Chromaticity Tracking Using a Phase Modulation Technique	betatron, synchrotron, controls, emittance	3910
	C.-Y. Tan
	Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the the RF frequency is varied. This paper will describe a way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency . The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in both the SPS and Tevatron and we will show the results here.

FRPMS020	Optical Beam Timing Monitor Experiments at the Advanced Light Source	laser, storage-ring, instrumentation, diagnostics	3952
	S. De Santis J. M. Byrd, R. B. Wilcox LBNL, Berkeley, California Y. Yin Y. Y. Labs, Inc., Fremont, California
	Funding: Work supported by the U. S. Department of Energy under Contract No. DE-AC0-05CH11231. We present the results of an experimental study of a beam timing monitor based on a technique demonstrated by Loehl. This technique uses the electrical signal from a beam position monitor to amplitude-modulate a train of laser pulses, converting timing jitter into an amplitude jitter. This modulation is then measured with a photodetector and sampled by a fast ADC. This approach has already demonstrated sub-100 fsec resolution and promises even better results. Our study focuses on the use of this technique for precision timing for storage rings. We show results of measurements using signals from the Advanced Light Source. F. Loehl, et al., Proc. of the 2006 EPAC., p. 2781.

FRPMS040	BPM signal conditioning for a wide range of single bunch current operation in Duke storage ring	single-bunch, storage-ring, booster, synchrotron	4042
	J. Li P. Wang, Y. K. Wu FEL/Duke University, Durham, North Carolina
	Funding: Supported by US DoE grant #DE-FG02-01ER41175. The beam position monitor system of the Duke storage ring has been in operation since 1998. Recently, by injecting at higher energy with a booster synchrotron, the single bunch current threshold is much more increased. This makes the BPM system do not work properly and rises the risk to damaged the BPM signal processing modules. To get reliable orbit data and protect the BPM modules, we carefully studied the BPM signal, and then found a way to overcome this problem. This paper will report the study results and the solution method.

FRPMS045	Non-Destructive Single Shot Bunch Length Measurements for the CLIC Test Facility 3	electron, klystron, linac, radiation	4069
	A. E. Dabrowski H.-H. Braun, R. Corsini, S. Doebert, T. Lefevre, F. Tecker, P. Urschutz CERN, Geneva M. Velasco NU, Evanston
	Funding: DOE A non-destructive bunch length detector has been installed in the CLIC Test Facility (CTF3). Using a series of down-converting mixing stages and filters, the detector analyzes the power spectrum of the electromagnetic field picked-up by a single waveguide. This detector evolved from an earlier system which was regularly used for bunch length measurements in CTF2. Major improvements are increase of frequency reach from 90 GHz to 170 GHz, allowing for sub-pico second sensitivity, and single shot measurement capability using FFT analysis from large bandwidth waveform digitisers. The results of the commissioning of the detector in 2006 are presented.

FRPMS053	Electromagnetic Modeling of Beam Position and Phase Monitors for LANSCE Linac	linac, coupling, simulation, diagnostics	4111
	S. S. Kurennoy
	Electromagnetic modeling has been used to compare pickup designs of the beam position and phase monitors (BPPM) for the Los Alamos Neutron Science Center (LANSCE) linac. This study is a part of the efforts to upgrade LANSCE beam diagnostics. MAFIA 3-D time-domain simulations with an ultra-relativistic beam allow computing the signal amplitudes and phases on the BPPM electrodes for the given processing frequency, 402.5 MHz, as functions of the beam transverse position. An analytical model can be applied to extrapolate the simulation results to lower beam velocities. Based on modeling results, a BPPM design with 4 one-end-shorted electrodes each covering 60-degree subtended angle, similar to the SNS linac BPPM, appears to provide the best combination of mechanical and diagnostics properties for the LANSCE side-coupled linac. J. D. Gilpatrick et al. These proceedings.** S. S. Kurennoy and R. E. Shafer, EPAC 2000 (Vienna, Austria, 2000), 1768.

FRPMS055	LANSCE Prototype Beam Position and Phase Monitor (BPPM) Mechanical Design	alignment, vacuum, isotope-production, linac	4123
	J. F. O'Hara M. J. Borden, D. C. Bruhn, J. L. Erickson, J. D. Gilpatrick, S. S. Kurennoy LANL, Los Alamos, New Mexico
	Funding: Work supported by United States Department of Energy A prototype Beam Position and Phase Monitor (BPPM) beam line device is being designed to go in the LANSCE 805-MHz linac. The concept is to install two beam line devices in locations where their measurements can be compared with older existing Delta-T loop and wire scanner measurements. The plan is to install two devices so that transverse position, angular trajectory, as well as central beam phase and energy will be measured. The mechanical design will combine features from previous LANL designs that were done for the LANSCE Isotope Production Facility, LANSCE Switchyard project, and those done for the SNS linac. This paper will discuss the mechanical design and fabrication issues encountered during the course of developing the BPPM.

FRPMS084	Detection of Instumental Drifts in the PEP II LER BPM System	sextupole, feedback, controls, optics	4261
	W. Wittmer A. S. Fisher, D. J. Martin, J. J. Sebek SLAC, Menlo Park, California
	Funding: US-DOE During the last PEP-II run a major goal was to bring the Low-Energy Ring optics as close as possible to the design. Sudden artificial jumps of the orbit, which were regularly observed by a large number of BPMs during routine operation, were interfering with this effort. The source of the majority of these jumps had been traced to the filter-isolator boxes (FIBs) near the BPM buttons. A systematic approach to find and repair the failing units had been developed and implemented. Despite this effort, the instrumental orbit jumps never completely disappeared. To trace the source of this behavior a test setup, using a spare Bergoz MX-BPM processor (kindly provided by SPEAR III at SSRL) was connected in parallel to various PEP-II BPM processors. In the course of these measurements a slow instrumental orbit drift was found which was clearly not induced by a moving positron beam. Based on the size of the system and the limited time before the end of PEP II an accelerator improvement project was initiated to install BERGOZ BPM-MX processors close to all sextupoles.