PAC07 - List of Keywords (alignment)

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alignment

Paper	Title	Other Keywords	Page
MOPAN044	Development of Commissioning Software System for J-PARC LINAC	linac, controls, quadrupole, lattice	257
	H. Sako C. K. Allen KEK, Ibaraki H. Ikeda Visual Information Center, Inc., Ibaraki-ken G. B. Shen JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	Beam commissioning of J-PARC LINAC has been performed since November 2006. A commissioning software framework and a database system have been developed for the commissioning. We first discuss the LINAC control system, and then our commissioning software framework. Then, we discuss our strategy of comparing online/offline data and models in our system with monitors, magnets, and the RF system. Commissioning tools developed during the commissioning will be presented in detail.

MOPAN076	Remote Inspection, Measurement and Handling for LHC	controls, radiation, survey, monitoring	332
	K. Kershaw F. Chapron, A. Y. Coin, F. Delsaux, T. Feniet, J. L. Grenard, R. V. Valbuena CERN, Geneva
	Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-date and future development plans.

MOPAN077	Geometry of the LHC Short Straight Sections Before Installation in the Tunnel: Resulting Aperture, Axis and BPM Positioning	quadrupole, insertion, laser, controls	335
	D. P. Missiaen P. Bestmann, M. C.L. Buzio, S. D. Fartoukh, M. Giovannozzi, J. B. Jeanneret, A. M. Lombardi, Y. Papaphilippou, S. Pauletta, J. C. Perez, H. Prin, E. Y. Wildner CERN, Geneva
	The Large Hadron Collider Short Straight Sections (SSS) are currently being installed in their final position in the accelerator tunnel. For all the SSSs, both those in the regular arcs as well as those in the insertion regions, magnetic and geometric measurements are made at different steps of their assembly. These stages range from production in the industry to the cryostating at CERN, as well as during and after cold tests or during installation of the BPM and the cold warm transition for the stand alone magnets. The results of the geometry at the various production stages by means of different procedures and analysis tools are reported and discussed in details in this paper.

MOPAN080	Modeling of Flexible Components for Asserting the Stability of Superconducting Magnets	vacuum, coupling, collider, hadron	341
	A. Kumar S. C. Bapna, S. Dutta, K. Swarna RRCAT, Indore (M. P.) A. Poncet CERN, Geneva
	Funding: Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, INDIA European Organisation for Nuclear Research (CERN), Geneva, Switzerland Superconducting magnets are subjected to various forces during their cool down and alignment. Their construction invariably includes bellows, gimbals, hoses and composite supports. A good estimate of the deformations arising out of the cool down and alignment operations is necessary as these induce relative displacements between the fiducialised external vessel and hidden cold mass of the magnet. The nonlinear and orthotropic behaviour of these elements may make the model complicated and if solved as a nonlinear problem, would entail a large solution time as the overall model size runs into million nodes. Authors developed a unified Finite Element Model of the LHC Short Straight Section and during this process many innovative modeling techniques evolved. The developed model uses isotropic material constitutive laws with linear material properties. The paper is presenting some of the salient features of these modeling techniques.

MOPAN100	Multiple Quadrupole Magnetic Center Alignment on the Girder	quadrupole, sextupole, laser, storage-ring	395
	L. Tsai T.-C. Fan, C.-S. Hwang, C. J. Lin, S. Y. Perng, D.-J. Wang NSRRC, Hsinchu
	Conventional alignments of quadrupole magnets on the girder based on the theodolite and fiducial was limited by human-eye resolution and fiducial precision. The accumulative error of group of magnetic centers may be more than 100 μm. In this paper, an automatic quadrupole magnetic center aligning method was proposed using pulsed wire method to align group of quadrupole magnets concentrically on one girder to higher precision. In order to increase the alignment precision, a short wire reduced sag problem in long wire, laser and position sensitive detector (PSD) system was to trace the wire position to level of micron. The precision of the alignment of quadrupole magnetic centers could be within 30μm. Descriptions of the setup and test results are presented.

MOPAS033	A Robust Orbit-Steering and Control Algorithm Using Quadrupole-scans as a Diagnostic	quadrupole, controls, dipole, electron	509
	C. Wu E. Abed, G. Bai, B. L. Beaudoin, S. Bernal, I. Haber, R. A. Kishek, P. G. O'Shea, M. Reiser, D. Stratakis, D. F. Sutter, K. Tian, M. Walter UMD, College Park, Maryland
	Funding: This work is funded by US Dept. of Energy. Beam based alignment and control has been a critical issue for many accelerators. In this paper, we've developed a new approach that can correct the beam orbit using a systematic quad-scan method, where there is an insufficient number of beam position monitors. In this approach, we've proposed a calibrated response matrix. This matrix takes consideration of the different sensitivities of different quadrupoles in the lattice. With the calibrated response matrix, we can greatly enhance our ability to control the beam centroid motion and reduce the control effort.

MOPAS047	LANSCE Fail Safe Radiation Shutter Design for Isotope Production Facility	target, radiation, shielding, controls	539
	M. J. Borden C. A. Chapman, C. T. Kelsey, J. F. O'Hara, J. Sturrock LANL, Los Alamos, New Mexico
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 Dose rate modeling and post irradiation measurements of the Isotope Production Facility beamline, at the Los Alamos Neutron Science Center (LANSCE) accelerator, have determined that a radiation shielding shutter is required to protect personnel from shine from irradiated targets for routine beam tunnel entries. This paper will describe radiation dose modeling, shielding calculations and the failsafe mechanical shutter design.

TUPMS059	LCLS Undulator Tuning And Fiducialization	undulator, electron, linac, free-electron-laser	1320
	Z. R. Wolf V. Kaplounenko, Yu. I. Levashov, A. W. Weidemann SLAC, Menlo Park, California
	Funding: Work supported in part by the DOE Contract DE-AC02-76SF00515. The LCLS x-ray free electron laser project at SLAC requires 40 undulators: 33 in the beamline, 6 spares, and one reference undulator. A new facility was constructed at SLAC for tuning and fiducializing the undulators. The throughput of the facility must be approximately one undulator per week. Much effort has gone into automating the undulator tuning. Because of tight alignment tolerances, accurate techniques were developed to fiducialize the undulators. The new facility, the tuning techniques, and the fiducialization techniques will be discussed.

TUPMS089	Thermal Emittance Measurement Design for Diamond Secondary Emission	electron, emittance, simulation, shielding	1374
	Q. Wu I. Ben-Zvi, A. Burrill, X. Chang, D. Kayran, T. Rao, J. Smedley BNL, Upton, Long Island, New York
	Thermal emittance is a very important characteristic of cathodes. A lower thermal emittance cathode has a better performance in limiting emittance for transport down the beam line. A diamond amplified photocathode, being a negative electron affinity (NEA) cathode, promises to deliver a very small thermal emittance. A carefully designed method of measuring the emittance of secondary emission from diamond is presented for the first time. Comparison of possible schemes is carried out by simulation, and the most accessible and accurate method and values are chosen. Systematic errors can be controlled within a very small range, and are carefully evaluated. Aberration and limitations of all equipment are taken into account.

TUPAN059	The Precise Survey and the Alignment Results of the J-PARC Linac	linac, survey, beam-transport, laser	1520
	T. Morishita H. Asano, M. Ikegami JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken K. Hasegawa JAEA, Ibaraki-ken A. Ueno JAEA/LINAC, Ibaraki-ken
	J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. A total length is more than 400 m including the beam transport line to the 3GeV RCS(Rapid Cycling Synchrotron). Precise alignment of the accelerator components is essential for high quality beam acceleration. After the completion of the linac building, floor elevation was surveyed periodically for more than one year to adjust the beam height from the ion source to the RCS. Before the beam commissioning, a metrological survey has been done. The reference points on the tunnel wall were set up to form a survey network to reduce the survey error less than 1mm in the entire linac. Based on the survey results, the linac components were re-aligned finely to satisfy the requirement. In this paper, the results of the floor elevation and the final alignment are described.

TUPAN060	The DTL/SDTL Alignment of the J-PARC Linac	linac, laser, target, survey	1523
	T. Morishita H. Asano, M. Ikegami, T. Ito JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken K. Hasegawa JAEA, Ibaraki-ken F. Naito, E. Takasaki, H. Tanaka, K. Yoshino KEK, Ibaraki A. Ueno JAEA/LINAC, Ibaraki-ken
	J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. The length of the linear section is about 300 m which consists of the ion source, the radio frequency quadropole linac(RFQ), the drift tube linac(DTL), separated type DTL(SDTL), and the beam transport line. Precise alignment of the accelerator components is essential for high quality beam acceleration. The required alignment error in the J-PARC linac is 0.1mm in transverse direction. In the DTL/SDTL section, the fine alignment was carried out by using an optical alignment telescope along with the cavity installation. The relay targets were placed at short intervals for smooth connection between neighboring components. After the installation, the DTL/SDTL positions were confirmed by measuring the reference base by using a laser tracker. In this paper, the alignment procedure for the DTL/SDTL section and the results by the laser tracker measurements are described.

TUPAN078	Design and Fabrication of the PEFP DTL II	vacuum, proton, pick-up, linac	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.

TUPAN107	Beam Loss Response Measurements with an LHC Prototype Collimator in the SPS	beam-losses, controls, collimation, impedance	1622
	Th. Weiler G. Arduini, R. W. Assmann, C. B. Bracco, H.-H. Braun, B. Dehning, P. Gander, E. B. Holzer, M. Jonker, R. Losito, A. Masi, L. Ponce, S. Redaelli, G. Robert-Demolaize, M. Sobczak, J. Wenninger CERN, Geneva
	Beam tests with an LHC prototype collimator were performed at the SPS in autumn 2006. Applying a new collimator control system many new beam measurements were performed. This contribution presents results on collimator-induced beam loss measurements and their applications to beam-based alignment of collimators and measurements of the beam size and position. Interesting features of the recorded beam loss signals are illustrated and possible impacts for LHC operation are discussed. The measured loss distributions around the full SPS ring are analyzed and compared with simulations.

TUPAN108	LHC Collimation System Hardware Commissioning	vacuum, collimation, collider, proton	1625
	Th. Weiler O. Aberle, R. W. Assmann, R. Chamizo, Y. Kadi, J. Lettry, S. Redaelli CERN, Geneva
	The stored energy and intensity of the LHC beam exceed the damage level of the machine and the quench level of the magnets by far. Therefore a robust and reliable collimation system is required which prevents the quenching of the magnets during regular operation and protects the accelerator components from damage in the event of beam loss. To assure that the installed collimators will protect the machine and permit the required performance of the collider, an appropriate hardware commissioning has to be implemented. In this contribution we describe the procedures for the hardware commissioning of the LHC collimation system. These procedures will establish the required precision and reliability of collimator movements and settings before the start of beam operation.

TUPAS055	End-to-End Beam Dynamics Simulations of the ISF Driver Linac	linac, simulation, emittance, ion	1775
	Q. Zhao M. Doleans, T. L. Grimm, F. Marti, S. O. Schriber, X. Wu, R. C. York NSCL, East Lansing, Michigan
	A proposed Isotope Science Facility (ISF), a major upgrade from the Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory (NSCL), will provide the nuclear science community with world-class beams of rare isotopes. The ISF driver linac will consist of a front-end and three acceleration segments of superconducting cavities separated by two charge-stripping sections, and will be capable of delivering primary beams ranging from protons to uranium with variable energies of ≥200 MeV/nucleon. The results of end-to-end beam simulation studies including physical misalignments, dynamic rf amplitude and phase errors, and variations in the stripping foil thickness, will be performed to evaluate the driver linac overall performances and beam loss, even for the challenging case of the uranium beam with multiple charge states using the newly-developed RIAPMTQ/IMPACT codes. The paper will discuss ISF beam dynamics issues and present the end-to-end beam simulation results.

WEOBAB02	Studies of Emittance Bumps and Adaptive Alignment method for ILC Main Linac	emittance, feedback, linac, linear-collider	1973
	N. Solyak V. Ivanov, C. S. Mishra, K. Ranjan Fermilab, Batavia, Illinois
	Funding: U. S. Department of Energy International Linear Collider (ILC) is a proposed electron-positron accelerator requiring very small spot-size at the interaction point, and thus necessitates very tight tolerances on beamline elements. For static tuning of the machine a few methods like dispersion-free steering (DFS) or kick minimization (KM) techniques was proposed. The further suppression of emittance growth can be achieved by using close orbit emittance bumps. Stability of ILC is determined by the stability of the site, additional noises of beamline component, energy and kicker jitter and performance of the train-to-train and intra-train feedback. We discuss the performances of the Adaptive Alignment technique, which keeps accelerator dynamically aligned in presence of ground motion an technical noises. This presentation is an overview of two posters THPMN107 and THPMN108, presented at PAC07.
	Slides

WEPMN104	Mechanical Stability Study of Type IV Cryomodule (ILC Prototype)	quadrupole, vacuum, linac, simulation	2277
	M. McGee R. Doremus, R. Wands Fermilab, Batavia, Illinois
	An ANSYS modal and harmonic finite element analysis (FEA) was performed in order to investigate cryomodule design mechanical stability for the proposed International Linear Collider (ILC). The current cryomodule, designated Type IV or T4CM, closely follows the Type III TESLA Test Facility (TTF) version used at DESY, with the exception of a proposed location of the superconducting (SC) quadrupole at the center. This analysis considered the stringent stability criteria established for the ILC, where vertical motion for the SC quad is limited to the micron range, at a few Hz. Model validation was achieved through Type II cryomodule vibration measurement studies performed at DESY. The effect of support location, support stiffness and other important parameters were considered in a parametric sensitivity study. FEA results, fast motion investigations and stabilization techniques are discussed. Operated by Universities Research Association, Inc., under Contract No. DE-AC02-76CH03000 with the U. S. Department of Energy#mcgee@fnal.gov

THOAKI02	The Cornell ERL Superconducting 2-Cell Injector Cavity String and Test Cryomodule	emittance, linac, cryogenics, damping	2572
	M. Liepe S. A. Belomestnykh, E. P. Chojnacki, V. Medjidzade, H. Padamsee, P. Quigley, J. Sears, V. D. Shemelin, V. Veshcherevich CLASSE, Ithaca
	Funding: Work supported by NSF. Cornell University is developing and fabricating a SRF injector cryomodule for the acceleration of the high current (100 mA) beam in the Cornell ERL prototype and ERL light source. Major challenges include emittance preservation of the low energy, ultra low emittance beam, cw cavity operation, and strong HOM damping with efficient HOM power extraction. Prototypes have been completed for the 2-cell niobium cavity with helium vessel, coaxial blade tuner with piezo fine tuners, twin high power input couplers, and beam line HOM absorbers loaded with ferrites and ceramics. Axial symmetry of HOM absorbers, together with two symmetrically placed input couplers per cavity, avoids transverse on-axis fields, which would cause emittance growth. A one-cavity cryostat has been designed following concepts of the TTF cryostat, and is presently under fabrication and assembly. The cryostat design has been optimized for precise cavity alignment, good magnetic shielding, and high dynamic cryogenic loads from the RF cavities, input couplers, and HOM loads. In this paper we report on the status of the assembly and first test of the one-cavity test cryostat.
	Slides

THICKI02	Design of Large-sized Accelerator Tunnel	synchrotron, controls, civil-engineering, heavy-ion	2697
	T. Kato A. Tamura Nikken Sekkei Civil Ltd, Tokyo
	There are several key points in designing the underground tunnel where large-sized accelerator is installed. The following two points are very important. (1) Transformation of the tunnel should be minimal. (2) Level of integrity and durability of the tunnel structure should be high. In order to accomplish minimal transformation of the tunnel and stable operation of the accelerator, we recommend not to provide the expansion joints in the tunnel concrete. As the result of structural analysis which we performed on temperature change inside the tunnel without expansion joints, we confirmed that there was few incidence of harmful cracks and transformation.
	Slides

THPMN003	Commissioning of the 100 keV Beam Stage of the Injector Linac of the IFUSP Microtron	microtron, linac, cathode, emittance	2710
	M. N. Martins A. L. Bonini, R. Lima, A. A. Malafronte, T. F. Silva USP/LAL, Sao Paulo
	Funding: Work supported by FAPESP and CNPq The injector linac consists of a beam conforming stage, with chopper and buncher systems, and two acceleration structures, the first one with variable β, and the second one divided into two parts with different β. There are two 3-mm diameter collimators, the first at the entrance to the first chopper cavity and the second at the entrance to the first acceleration structure. The beam focalization is made by solenoids, and correcting coils are provided for steering. In this work we describe the commissioning of the optical lattice of the conforming beam stage. The first beam images are shown.

THPMN045	Design and Control of Emittance Growth of Short Bunch Compressor for International Linear Collider	emittance, quadrupole, lattice, optics	2814
	E.-S. Kim
	We present an alternative design with the short system length in the bunch compressors for the International Linear Collider(ILC). We show the characteristics and performances of the designed system in detail. We also present orbit and dispersion correction schemes for the compensation of emittance growths, vertical dispersion and skew-component that may be generated by several machine errors in the system. In result, it is shown that the short bunch compressor system satisfies the required beam conditions for the ILC.

THPMN061	Bunch Compressor for Beam-Based Alignment	linac, emittance, simulation, quadrupole	2844
	A. Latina P. Eliasson Uppsala University, Uppsala D. Schulte CERN, Geneva
	Funding: Supported by the European Community under the 6th Framework Programme "Structuring the European Research Area". Misalignments in the main linac of future linear colliders can lead to significant emittance growth. Beam-based alignment algorithms, such as Dispersion Free Steering (DFS), are necessary to mitigate these effects. We study how to use the Bunch Compressor to create the off-energy beams necessary for DFS and discuss the effectiveness of this method.

THPMN062	Dynamic Effects During Beam-Based Alignment	emittance, quadrupole, linac, simulation	2847
	D. Schulte P. Eliasson, A. Latina CERN, Geneva
	Funding: Supported by the European Community under the 6th Framework Programme "Structuring the European Research Area". Complex beam-based alignment procedures are needed in future linear colliders to reduce the negative effects of static imperfections in the main linac on the beam emittance. The efficiency of these procedures could be affected by dynamic imperfections during their application. In this paper we study the resulting emittance growth.

THPMN075	Alignment Sensitivities in the ILC Damping Rings	emittance, lattice, quadrupole, damping	2877
	K. G. Panagiotidis A. Wolski Liverpool University, Science Faculty, Liverpool
	For the International Linear Collider to reach its design luminosity, the damping rings must achieve a vertical emittance that is a factor of two below that achieved in any operating storage ring so far. Magnet alignment, orbit control and coupling correction are therefore critical issues for the ILC damping rings. We compare alignment sensitivities in some recent designs for the ILC damping ring lattices, and discuss the results of tuning simulations using different algorithms for correcting the vertical dispersion and the coupling.

THPMN079	Simulation of ILC Feedback BPM Signals in an Intense Background Environment	background, feedback, simulation, extraction	2889
	A. F. Hartin R. Arnold, S. Molloy, S. Smith, M. Woods SLAC, Menlo Park, California P. Burrows, G. B. Christian, C. I. Clarke, B. Constance, H. D. Khah, C. Perry, C. Swinson, G. R. White JAI, Oxford A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Funding: This work is supported in part by the Commission of the European Communities under the 6th Framework Programme "Structuring the European Research Area", contract number RIDS-011899. Experiment T-488 at SLAC, End Station A recorded distorted BPM voltage signals and an accurate simulation of these signals was performed. Geant simulations provided the energy and momentum spectrum of the incident spray and secondary emissions, and a method via image charges was used to convert particle momenta and number density into BPM stripline currents. Good agreement was achieved between simulated and measured signals. Further simulation of experiment T-488 with incident beam on axis and impinging on a thin radiator predicted minimal impact due to secondary emission. By extension to worst case conditions expected at the ILC, simulations showed that background hits on BPM striplines would have a negligible impact on the accuracy of beam position measurements and hence the operation of the FONT feedback system

THPMN104	Recent Studies of Dispersion Matched Steering for the ILC Bunch Compressor and Main Linac	emittance, linac, quadrupole, injection	2954
	P. Lebrun L. Michelotti, J.-F. Ostiguy Fermilab, Batavia, Illinois
	Beam Based Alignment techniques are expected to play a critical role to the emittance preservation for the ILC. The Dispersion Free Steering (DFS) method is studied in detail in the 2nd statge of the bunch Compressor and in the beginning of the curved Main Linac. It is shown than in absence of cavity tilts (rotations on the YZ plane), DMS provides a unique and stable solution with negligible emittance growth. If cavity tilts are about 200 to 300 micro-radiant, the DMS solution is no longer unique and significant emittance occurs as well. While within the ILC budget, other dynamical effects, such a large beam jitter or sudden ground motion will cause severe performance degradation. A Variant of the DFS algorithm can be used to re-aling cavity supports, leading to better LET performance. In presence of perturbations (klystron jitter, ground motion,.. ) such DFS solutions are easier to maintain and improved if they are stable and unique. Therefore, it is suggested to consider using movers on quadrupole/BPM and, a bit more controversial, for the support system of the r.f. cavities, especially at low energy, where spurious dispersion due to cavity tilts are large.

THPMN107	Study of Emittance Bumps in The ILC Main Linac	emittance, linac, simulation, quadrupole	2960
	N. Solyak K. Ranjan Fermilab, Batavia, Illinois
	Funding: U. S. Department of Energy This paper reports the studies of using global emittance tuning bumps to limit the emittance growth to very small values in the main linac of the proposed International Linear Collider (ILC) machine. Simulation studies indicate that closed-orbit emittance bumps, when used after local or quasi-local beam based alignment techniques, can be utilized to further suppress the emittance growth in the ILC main linac. A series of simulations are performed to find the optimal number of bumps and their locations. A more general method of optimizing the emittance bumps in the ILC main linac is also discussed.

THPMN108	Study of Adaptive Alignment as Beam Based Alignment in ILC Main Linac in the Presence of Ground Motion	emittance, linac, ground-motion, lattice	2963
	N. Solyak V. Ivanov, C. S. Mishra, K. Ranjan Fermilab, Batavia, Illinois
	Funding: U. S. Department of Energy The proposed International Linear Collider (ILC) machine requires extremely small transverse emittances of the beam to achieve desired luminosity. A very precise alignment of the beamline elements, both in main linac and in beam delivery system, is required to limit the emittance growth. However, ground motion (GM) and technical noise continuously misaligns the elements and hence spoils the effect of alignment. It is thus very important to understand and analyze the effect of GM on the performance of ILC. Also, it is imperative to find an effective dynamic alignment procedure to preserve the transverse emittances in the presence of GM. In this paper we study the effect of GM and technical noise on the proposed ILC main linac. Initial alignment of the Linac is performed through one-to-one and dispersion free steering (DFS). We then study "Adaptive Alignment" method to mitigate the effects of GM and technical noise.

THPMS015	Observation of Multi-GeV Breakdown Thresholds in Dielectric Wakefield Structures	electron, laser, radiation, simulation	3026
	M. C. Thompson, H. Badakov, J. B. Rosenzweig, M. C. Thompson, G. Travish UCLA, Los Angeles, California M. J. Hogan, R. Ischebeck, N. A. Kirby, R. Siemann, D. R. Walz SLAC, Menlo Park, California P. Muggli USC, Los Angeles, California A. Scott UCSB, Santa Barbara, California R. B. Yoder Manhattan College, Riverdale, New York
	Funding: This work was performed under the auspices of the US Department of Energy under Contracts No. DE-FG03-92ER40693, DE-AC02-76SF00515, W-7405-ENG-48, and DE-FG02-92-ER40745. The breakdown threshold of a dielectric subjected to the GV/m-scale electric-fields of an intense electron-beam has been measured. In this experiment at the Final Focus Test Beam (FFTB) facility, the 30 GeV SLAC electron beam was focused down and propagated through short fused-silica capillary-tubes with internal diameters of as little as 100 microns. The electric field at the inner surface of the tubes was varied from about 1 GV/m to 22 GV/m by adjusting the longitudinal compression of the electron bunch. The onset of breakdown, as indicated by a bright discharge, was found to correlate to a surface field of about 4 GV/m. An analysis of the damage sustained to the beam-exposed fibers, and its correlation to field amplitude, is also reported.

THPAN025	Evaluation of the Component Tolerances for the ILC Main Linac Assuming Global Linear Corrections	emittance, linac, coupling, quadrupole	3280
	F. Poirier D. Kruecker, N. J. Walker DESY, Hamburg
	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. The small energy-spread, weak wakefields and relatively weak focusing in the ILC superconducting Main Linac result in little or no filamentation beam mismatch errors: linear correlations such as dispersion or cross-plane coupling from transverse misalignment or rotation errors of the quadrupoles respectively do not decohere as the beam is transported (accelerated) along the linac. Using correction available in the Beam Delivery System, the increase in projected emittance due to this linear correlations can to a large degree be corrected. In this paper we present component tolerances based on the assumption of a global correction at the end of the Main Linac. Some discussion on the impact of ground motion is also discussed.

THPAN034	New Simulation Code for Synchrotron Radiation Based on a Real Beam Orbit	synchrotron-radiation, simulation, monitoring, synchrotron	3304
	T. Abe
	A computer code to simulate synchrotron-radiation power and spatial distributions has been developed based on the method by T. Abe and H. Yamamoto, where a real beam orbit is obtained by fitting measurements of beam-position monitors (BPMs) with some offset corrections for BPMs and magnet alignments. In this paper, the basic performance and application are presented. This code has been rewritten in Fortran95 so as to obtain expectable maximal speed-up by parallel computing, aiming at online alarm systems to take precautions against synchrotron-radiation damage, toward higher beam current accelerators. T. Abe and H. Yamamoto, Phys. Rev. ST Accel. Beams 7, 072802 (2004)

THPAS091	BPM Calibration Independent LHC Optics Correction	quadrupole, simulation, optics, heavy-ion	3693
	R. Calaga R. Tomas, F. Zimmermann CERN, Geneva
	Funding: This work is partially supported by the U. S. DOE The tight mechanical aperture for the LHC imposes severe constraints on both the beta and dispersion beating. Robust techniques to compensate these errors are critical for operation of high intensity beams in the LHC. We present simulations using realistic errors from magnet measurements and alignment tolerances in the presence of BPM noise. Correction reveals that the use of BPM calibration and model independent observables are key ingredients to accomplish optics correction. Experiments at RHIC to verify the algorithms for optics correction are also presented.

FROAKI01	Magnet Acceptance and Allocation at the LHC Magnet Evaluation Board	quadrupole, dipole, superconducting-magnet, insertion	3739
	L. Bottura P. Bestmann, N. Catalan-Lasheras, S. D. Fartoukh, S. S. Gilardoni, M. Giovannozzi, J. B. Jeanneret, M. Karppinen, A. M. Lombardi, K. H. Mess, D. P. Missiaen, M. Modena, R. Ostojic, Y. Papaphilippou, P. Pugnat, S. Ramberger, S. Sanfilippo, W. Scandale, F. Schmidt, N. Siegel, A. P. Siemko, D. Tommasini, T. Tortschanoff, E. Y. Wildner CERN, Geneva
	The normal- and superconducting magnets for the LHC ring have been carefully examined to insure that each of the more than 1800 assemblies is suitable for the operation in the accelerator. Magnet coordinators, hardware experts and accelerator physicists, joined in the LHC Magnet Evaluation Board, have contributed to this work that consists in the magnet acceptance, and the optimisation achieved by sorting magnets according to their geometry, field quality and quench level. This paper gives a description of the magnet approval mechanism that has been running since four years, reporting in a concise summary on the main results achieved. We take as specific indicators the computed mechanical aperture, the sorting efficiency with respect to systematic and random field errors in the magnets, and the case-by-case analysis necessary to accommodate hardware limitations such as quench limits and training.
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FROBC02	RF Structures for Linac4	linac, coupling, klystron, quadrupole	3821
	F. Gerigk N. Alharbi, M. Pasini, S. Ramberger, M. Vretenar, R. Wegner CERN, Geneva
	Linac4 is proposed to replace the existing proton linac at CERN (Linac2). Using an increased injection energy of 160 MeV instead of 50 MeV Linac4 is expected to double the beam intensity in the PS Booster and will thus be the first step towards higher brightness beams in the LHC. In this paper we re-assess the choice of RF structures for Linac4. Different accelerating structures for different energy ranges are compared in terms of RF efficiency, ease of construction and alignment, necessary infrastructure, and cost. Eventually we present the final choice of structures for Linac4.
	Slides

FRPMN102	An Instrument Design for the Accurate Determination of the Electron Beam Location in the Linac Coherent Light Source Undulator	undulator, electron, vacuum, linac	4324
	J. L. Bailey D. Capatina, J. W. Morgan ANL, Argonne, Illinois H.-D. Nuhn SLAC, Menlo Park, California
	Funding: Work supported by U. S. Department of Energy, under Contract Nos. DE-AC02-06CH11357 and DE-AC03-76SF00515. The Linac Coherent Light Source (LCLS), currently under design, requires accurate alignment between the electron beam and the undulator magnetic centerline. A Beam Finder Wire (BFW) instrument has been developed to provide beam location information that is used to move the undulators to their appropriate positions. A BFW instrument is mounted at each of the 33 magnets in the undulator section. Beam detection is achieved by electrons impacting two carbon fiber wires and then sensing the downstream radiation. The wires are mounted vertically and horizontally on a wire card similar to that of a traditional wire scanner instrument. The development of the BFW presents several design challenges due to the need for high accuracy of the wires' location and the need for removal of the wires during actual operation of the LCLS (30 microns repeatability is required for the wire locations). In this paper, we present the technical specification, design criteria, mechanical design, and results from prototype tests for the BFW.

FRPMN111	Design and Performance of the LCLS Cavity BPM System	undulator, dipole, linac, coupling	4366
	R. M. Lill L. H. Morrison, W. E. Norum, N. Sereno, G. J. Waldschmidt, D. R. Walters ANL, Argonne, Illinois S. Smith, T. Straumann SLAC, Menlo Park, California
	Funding: Work supported by U. S. Department of Energy under Contract Nos. DE-AC02-06CH11357 and DE-AC03-76SF00515 In this paper we present the design of the beam position monitor (BPM) system for the LCLS undulator, which features a high resolution X-band cavity BPM. Each BPM has a TM010 monopole reference cavity and a TM110 dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low-noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. We will discuss the system specifications, design, and prototype test results.

FRPMS011	Design of an Electro-Optical Sampling Experiment at the AWA Facility	laser, background, electron, monitoring	3901
	J. Ruan H. Edwards, V. E. Scarpine, C.-Y. Tan, R. Thurman-Keup Fermilab, Batavia, Illinois YL. Li, J. G. Power ANL, Argonne, Illinois T. J. Maxwell Northern Illinois University, DeKalb, Illinois
	Funding: Supported by US DOE The free space electro-optical (EO) sampling technique is a powerful tool for analyzing the longitudinal charge density of an ultrashort e-beam. In this paper, we present experimental results for a laser-based mock-up of the EO experiment* and a design for a beam-based, single-shot, EO sampling experiment using the e-beam from the Argonne Wakefield Accelerator (AWA) RF photoinjector. For the mock-up, a tabletop terahertz experiment is conducted in the AWA laser room. The mock-up uses an IR beam incident on <110> ZnTe crystal to produce a THz pulse via optical rectification. Detection is based on the cross correlation between the THz field and the probe IR laser field in a second <110> ZnTe crystal. Potential application of this technique to the ILC accelerator test facility at Fermilab is also presented. * Yuelin Li, Appl. Phys. Lett. 88, 251108, 2006

FRPMS049	Resolution of a High Performance Cavity Beam Position Monitor System	extraction, coupling, laser, emittance	4090
	S. Walston S. T. Boogert Royal Holloway, University of London, Surrey C. C. Chung, P. Fitsos, J. Gronberg LLNL, Livermore, California J. C. Frisch, S. Hinton, J. May, D. J. McCormick, S. Smith, T. J. Smith, G. R. White SLAC, Menlo Park, California H. Hayano, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki Yu. G. Kolomensky, T. Orimoto UCB, Berkeley, California P. Loscutoff LBNL, Berkeley, California A. Lyapin, S. Malton, D. J. Miller UCL, London R. Meller Cornell University, Department of Physics, Ithaca, New York M. C. Ross Fermilab, Batavia, Illinois M. Slater, M. Thomson, D. R. Ward University of Cambridge, Cambridge V. Vogel DESY, Hamburg
	International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved – ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of ± 20 microns.

FRPMS055	LANSCE Prototype Beam Position and Phase Monitor (BPPM) Mechanical Design	vacuum, isotope-production, linac, pick-up	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.