beam-losses

Paper	Title	Other Keywords	Page
MOPC064	Beam Losses Due to Intra-Beam and Residual Gas Scattering for Cornell's Energy Recovery Linac	radiation, scattering, undulator, simulation	214
	A. Temnykh Cornell University, Department of Physics, Ithaca, New York M. P. Ehrlichman, G. Hoffstaetter CLASSE, Ithaca
	In this paper we analyze particle loss rates in Cornell's x-ray Energy Recovery Linac. Because of the small beam emittances and high beam intensity, intra-beam scattering (IBS) can be a source of significant particles loss in the horizontal plane. It will result in radiation doses which should be carefully examined for adequate radiation protection. Additionally, scattering on the residual gas (RGS) causes particle losses in the vertical plane. With Mote-Carlo type simulations of the scattering processes and transport matrixes for particle-trajectory propagation we found the beam loss distribution along ERL. It indicated that 99% of the total beam loss will be due to IBS. However, the RGS contribution can not be ignored because it dominates scattering in the vertical plane causing IDs irradiation and damage. For both (IBS and RGS) processes the highest beam losses will occur at the end of deacceleration due to adiabatic anti-damping causing traverse betatron amplitudes to increase. These beamlosses can be consentrated in collimation sections. Knowing RGS beam loss rates at the ID locations, we estimate the ID’s life time and suggest a radiation protection scheme.
MOPC091	Benchmarking of Collimation Tracking Using RHIC Beam Loss Data	collimation, simulation, proton, insertion	274
	G. Robert-Demolaize, K. A. Drees BNL, Upton, Long Island, New York
	State-of-the-art tracking tools were recently developed at CERN to study the cleaning efficiency of the Large Hadron Collider (LHC) collimation system. These tools can be benchmarked using data taken from operations of the Relativistic Heavy Ion Collider (RHIC) multi-stage collimation system. This article reviews preliminary simulation results on both the location and the intensity of proton losses around the RHIC lattice. Comparison with live measurements from the beam loss monitors are also shown in order to assess the accuracy of the predictions in the LHC case.
MOPC095	Mechanical and Thermal Prototype Testing for a Rotatable Collimator for the LHC Phase II Collimation Upgrade	simulation, collimation, power-supply, impedance	286
	J. C. Smith, J. E. Doyle, L. Keller, S. A. Lundgren, T. W. Markiewicz SLAC, Menlo Park, California
	The Phase II upgrade to the LHC collimation systems calls for complementing the 30 high robust Phase I graphite collimators with 30 high Z, low impedance Phase II collimators. The design for the collimation upgrade has not been finalized. One option is to use metallic rotatable collimators and this design will be discussed here. The Phase II collimators must be robust in various operating conditions and accident scenarios. A series of prototype collimator jaws have been tested for both mechanical and thermal compliance with the design goals. Collimator jaw shape after thermal expansion benchtop tests were compared to ANSYS simulation results. Mechanical tests were also performed to demonstrate fabrication precision and collimator movement operation as designed.
MOPC099	Ion Catcher System for the Stabilisation of the Dynamic Pressure in SIS18	ion, vacuum, electron, controls	295
	C. Omet, H. Kollmus, H. Reich-Sprenger, P. J. Spiller GSI, Darmstadt
	In synchrotrons operated with intermediate charge state heavy ion beams, intensity dependent beam losses have been observed. The origin of these losses is the change of charge state of the beam ions at collisions with residual gas atoms. The resulting m/q deviation from the reference beam ion leads to modified trajectories in dispersive elements, which finally results in beam loss. At the impact on the beam pipe, gas molecules are released by ion stimulated desorption which increase the vacuum pressure locally. In turn, this pressure rise will enhance the charge change- and particle loss process and finally cause significant beam loss within a very short time. In order to suppress and control the gas desorption process, a dedicated ion catcher system incorporating NEG coated surfaces and low-desorption rate materials has been developed and two prototypes were installed in SIS18. The design of the scraper and measured effect on the dynamic residual gas pressure are presented.
MOPC100	Design Status of the FAIR Synchrotrons SIS100 and SIS300 and the High Energy Beam Transport System	extraction, synchrotron, acceleration, dipole	298
	P. J. Spiller, U. B. Blell, O. Boine-Frankenheim, E. S. Fischer, G. Franchetti, F. Hagenbuck, I. Hofmann, J. E. Kaugerts, M. Kauschke, M. Kirk, H. Klingbeil, A. Kraemer, D. Krämer, G. Moritz, C. Omet, N. Pyka, H. Ramakers, S. Ratschow, A. Saa-Hernandez, M. Schwickert, J. Stadlmann, H. Welker GSI, Darmstadt A. D. Kovalenko JINR, Dubna, Moscow Region
	The present status of system- and technical design and R&D for the new heavy ion synchrotrons SIS100 and SIS300 and the HEBT system is summarized. The overall machine planning and the general layout has been completed and the detailed technical machine design has been started. Device and component specifications, technical parameter lists and technical design reports are in preparation with the goal to enable international partners or industry to finalize the component design to achieve production readiness. In the frame of international working groups the distribution and sharing of the work packages, especially of the cryomagnetic system is under discussion.
MOPC121	Progress on Dual Harmonic Acceleration on the ISIS Synchrotron	acceleration, power-supply, synchrotron, proton	349
	A. Seville, D. Bayley, I. S.K. Gardner, J. W.G. Thomason, C. M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon D. J. Adams STFC/RAL/ASTeC, Chilton, Didcot, Oxon
	The ISIS synchrotron at the Rutherford Appleton Laboratory in the UK is currently undergoing an RF upgrade. Four, h=4 cavities have been installed in addition to the existing 6, h=2, cavities and should be capable of increasing the operating current from 200 to 300 μA. Two of the four cavities have been in operation for the last 2 user cycles improving trapping lossess and increasing operating currents beyond 200 μA. The remaining two cavities were commissioned in the spring of 2008. This paper reports on hardware commissioning, beam tests and beam simulation results.
MOPC133	Radiation Level in the J-PARC Rapid Cycling Synchrotron after First Study	injection, acceleration, proton, synchrotron	382
	K. Yamamoto, N. Hayashi, S. Hiroki, R. Saeki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken K. Satoh, M. Tejima KEK, Ibaraki T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken
	The 3GeV RCS (Rapid-Cycling Synchrotron) in J-PARC has been commissioned in October of 2007. The most important issue in the beam study is to reduce unnecessary beam loss and to keep the beam line clean for the sake of maintenance and upgrade of the machines. In order to achieve this purpose, we observed the beam loss monitors located around the RCS beam line and observed them for beam commissioning. We also investigated the residual dose of accelerator components during an interval of beam study. From these results, we found that beam loss points were the injection junction point, the branch of H0 dump and extraction line, transverse collimators, and dispersion maximum points in the arcs. Especially, the entrance of the primary collimator chamber and the current transformer of the H0 dump line were the most radio-activated points in the RCS. To make the best use of these results for beam commissioning, we managed to minimize the beam losses and succeeded in suppressing the residual dose to a level low enough to allows us to work close to those components.
MOPC136	Beam Bunch Leakage and Control in the SNS Ring	simulation, extraction, accumulation, linac	391
	Y. Zhang, J. Galambos ORNL, Oak Ridge, Tennessee
	In recent neutron production operations at SNS, beams contaminated the longitudinal extraction gap of the accumulator ring due to the limitation of the beam choppers. It caused significant beam loss and activation in the ring and in the extraction beam line. From simulations with computer models and in experimental measurements, properly utilizing the ring RF systems with additional storage turns after the beam accumulations in the ring effectively reduced beam loss in the SNS accelerator systems. Simulations and beam measurement results will be discussed
MOPP011	Fast Vertical Beam Instability in the CTF3 Combiner Ring	linac, injection, simulation, closed-orbit	574
	R. Corsini, D. Schulte, P. K. Skowronski, F. Tecker CERN, Geneva D. Alesini, C. Biscari, A. Ghigo INFN/LNF, Frascati (Roma)
	The CLIC Test Facility CTF3 is being built at CERN by an international collaboration, in order to demonstrate the main feasibility issues of the CLIC two-beam technology by 2010. The facility includes an 84 m combiner ring, which was installed and put into operation in 2007. High-current operation has shown a vertical beam break-up instability, leading to high beam losses over the four turns required for nominal operation of the CTF3 ring. Such instability is most likely due to the vertically polarized transverse mode in the RF deflectors used for beam injection and combination. In this paper we report the experimental data and compare them with simulations. Possible methods to eliminate the instability are also outlined.
MOPP081	Engineering Design of a PETS Tank Prototype for CTF3 Test Beam Line	vacuum, alignment, controls, damping	739
	D. Carrillo, L. García-Tabarés, J. L. Gutierrez, I. Rodriguez, E. Rodríguez García, S. Sanz, F. Toral CIEMAT, Madrid G. Arnau-Izquierdo, N. C. Chritin, S. Doebert, G. Riddone, I. Syratchev, M. Taborelli CERN, Geneva J. Calero CEDEX, Madrid
	In the CLIC concept, PETS (Power Extraction and Transfer Structure) role is to decelerate the drive beam and transfer RF power to the main beam. One of the CTF3 test beam line (TBL) aims is to study the decelerated beam stability and evaluate PETS performance. The PETS core is made of eight 800 mm long copper rods, with very tight tolerances for shape (± 20 micron), roughness (less than 0.4 micron) and alignment (± 0.1 mm). Indeed, they are the most challenging components of the tank. This paper reports about the methods of fabrication and control quality of these bars. A special test bench has been designed and manufactured to check the rod geometry by measuring the RF fields with an electric probe. Other parts of the PETS tank are the power extractor, the waveguides and the vacuum tank itself. Industry is partially involved in the prototype development, as the series production consists of 15 additional units, and some concepts could be even applicable to series production of CLIC modules
MOPP149	Recent Developments of the Superconducting CH-Cavities	simulation, cryogenics, linac, resonance	901
	H. Podlech, A. Bechtold, M. Busch, F. Dziuba, H. Liebermann, U. Ratzinger IAP, Frankfurt am Main
	The Crossbar-H-mode (CH)-structure which has been developed at the IAP in Frankfurt is a multi-cell drift tube structure for the efficient acceleration of low and medium energy protons and ions. The superconducting low energy CH-prototype cavity has reached gradients of up to 7 MV/m, corresponding to an effective voltage gain of 5.6 MV. This shows that high real estate gradients can be achieved in superconducting low energy multi-cell cavities. Additionally, microphonics and tuning measurements have been performed at room temperature and at 4K. Optimized cavity geometry for high power beam projects and plans for the construction of a new superconducting cavity will be presented.
TUOCM03	Beam Loss Position Monitoring with Optical Fibres at DELTA	radiation, injection, storage-ring, vacuum	1032
	F. Rüdiger, G. Schmidt, K. Wille DELTA, Dortmund W. Goettmann HMI, Berlin M. Koerfer DESY, Hamburg
	Detection of ionising radiation with optical fibres is used to localize beam losses. At DELTA three different systems are in use. Optical Time Domain Reflectometry (OTDR) is used to measure radiation doses along the full length of the storage ring vacuum chamber. Transmission measurement of optical fibre loops is used for surveillance of radiation sensitive objects like Undulator permanent magnets. Integration into the DELTA control system offers the possibility to react on increased doses within several minutes. Detection of Cerenkov radiation offers real-time beam loss position monitoring with single-bunch resolution of 2 ns. With up to four fibres mounted at different positions along the vacuum chamber spatial measurement of beam loss is used to increase injection efficiency.
	Slides
TUPC006	A CompactRIO-based Beam Loss Monitor for the SNS RF Test Cave	radiation, controls, diagnostics, power-supply	1050
	W. Blokland, G. Armstrong ORNL, Oak Ridge, Tennessee
	An RF Test Cave has been built at the Spallation Neutron Source (SNS) to be able to test RF cavities without interfering the SNS accelerator operations. In addition to using thick concrete wall to minimize radiation exposure, a Beam Loss Monitor (BLM) must abort the operation within 100 μsec when the integrated radiation within the cave exceeds a threshold. We choose the CompactRIO platform to implement the BLM based on its performance, cost-effectiveness, and rapid development. Each in/output module is connected through an FPGA to provide point-by-point processing. Every 10 μsec the data is acquired analyzed and compared to the threshold. Data from the FPGA is transferred using DMA to the real-time controller, which communicates to a gateway PC to talk to the SNS control system. The system includes diagnostics to test the hardware and integrates the losses in real-time. In this paper we describe our design, implementation, and results.
TUPC037	Development, Production and Testing of 4500 Beam Loss Monitors	vacuum, radiation, simulation, target	1134
	E. B. Holzer, P. Chiggiato, B. Dehning, G. Ferioli, V. Grishin, J. M. Jimenez, M. Taborelli, I. Wevers CERN, Geneva A. Koshelev, A. Larionov, V. Seleznev, M. Sleptsov, A. Sytin IHEP Protvino, Protvino, Moscow Region D. K. Kramer TUL, Liberec
	Beam-loss monitoring (BLM) is a key element in the LHC machine protection. 4250 nitrogen filled ionization chambers (IC) and 350 secondary emission monitors (SEM) have been manufactured at the Institute for High Energy Physics (IHEP) in Protvino, Russia, following their development at CERN. Signal speed and robustness against ageing were the main design criteria. Each monitor is permanently sealed inside a stainless-steel cylinder. The quality of the welding was a critical aspect during production. The SEMs are requested to hold a vacuum of 1·10-7 bar. Impurity levels from thermal and radiation-induced desorption should remain in the range of parts per million in the ICs. The difference in sensitivity is about 3·104. To avoid radiation aging (up to 2·108 Gy in 20 years) production of the chambers followed strict UHV requirements. IHEP designed and built the UHV production stand. Due to the required dynamic range of 1·109, the leakage current of the monitors has to stay below 1 pA. Several tests during and after production were performed at IHEP and CERN. A consistently high quality during the whole production period was achieved and the tight production schedule kept at the same time.
TUPC050	A Complete Solution for Beam Loss Monitoring	monitoring, controls, vacuum, injection	1170
	M. Kobal, J. Dedic, R. Stefanic Cosylab, Ljubljana J. F. Bergoz BERGOZ Instrumentation, Saint Genis Pouilly
	In particle accelerator facilities knowing the beam loss is crucial for the machine to be running at optimal efficiency. Beam loss can be monitored on different time scales. Time scale of seconds is used at normal operation to detect any irregularities such as changes in the beta function or vacuum drop. Time scale of 1 ms is used to optimize injection, and 1 μs timescale in case of severe problems when the beam does not live for more than a couple of turns. The presented beam loss system (microIOC-BLM) uses Bergoz BLM sensors, Beam loss Signal Conditioner (BSC) for data acquisition and microIOC-CosyIcon as the central processing unit. The system is cost effective, portable and can be expanded with additional measuring points. Selectable counting interval from 100 μs to 10 s covers a large part of the required time scales. The minimum and maximum count rates are limited by the sensor between 1/s to 10 M./s. Trigger and gate signals are supported as is summing over a number of measurements.
TUPC093	Beam Profile Monitor of the J-PARC 3GeV Rapid Cycling Synchrotron	electron, ion, synchrotron, linac	1275
	K. Satou, N. Hayashi, R. Saeki, A. Ueno, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken H. Harada Hiroshima University, Graduate School of Science, Higashi-Hiroshima S. Lee, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken M. Tejima KEK, Ibaraki
	To obtain high intensity (1MW) and large emittance (214 π mm mrad) beam profiles of the 3GeV Rapid Cycling Synchrotron (RCS) of the J-PARC, we have developed the ionization profile monitors (IPMs) with wide active aperture and high dynamic range. It has three Microchannel Plates (MCPs) with active area of 81*41mm for signal multiplication and read out devices, and magnet system to generate guiding fields to collect electrons. The wide active aperture of ±116mm is obtained by arranging the three MCPs perpendicular to the beam axis. Furthermore, the dynamic range of 104 level can be obtained by adjusting each bias voltage of the MCPs. The IPMs are now collecting ions without the guiding fields. The beam commissioning of the RCS has been in progress since last year. The horizontal and vertical profiles are of great help, particularly to check injection errors. At the conference, the present status of the IPM system and the latest beam profiles will be reported.
TUPC096	Development of Beam Loss Monitor for the SPring-8 Storage Ring	injection, electron, target, background	1284
	Y. Shimosaki, K. Kobayashi, M. Oishi, M. Shoji, K. Soutome, Y. Taniuchi JASRI/SPring-8, Hyogo-ken
	A beam loss monitor using PIN photodiodes has been developed. To check its performance, we installed it at an in-vacuum insertion device and at the injection section in the SPring-8 storage ring. Information on the beam loss at these points will be useful for examining demagnetization of permanent magnets of insertion devices and for studying a mechanism of beam loss. A noise level at these points is however high due to stray synchrotron radiation, an induction voltage generated by pulsed injection magnets, etc. The beam loss signal is then picked up under a high noise condition. Experimental results with its countermeasure will be reported.
TUPC112	Equipment for Electrons Energy Measurement in HLS	electron, storage-ring, polarization, energy-calibration	1326
	H. Xu, G. Feng, B. Sun, L. Wang, J. F. Zhang, X. Zhao USTC/NSRL, Hefei, Anhui
	The parameters necessary to dimension an equipment for the measurement of the beam energy of a storage ring via the resonance depolarisation are collected for HLS . The electron beam polarizes naturally due to the Sokolov-Ternv effect. For Hefei light source(HLS), the polarisation time is approx 4.346 h at 800MeV. The calculated value 4.346h is only for reference. The radial field will be applied to the beam by a pair of striplines mounted in the storage ring vacuum chamber. When input power is 12.5w, with OPRA program, intergrated field is calculated on axial. Different input power V. S integral field is also calculated. Which the depolarization time V. S input power can calculated by the below. The beam loss system for the electron storage ring of HLS can be used to measure the relative change of Touschek lifetime. It is expected that the relative change of Touschek lifetime due to beam depolarization will be measured in the future.
TUPD040	Design, Manufacturing and Tests of a Micrometer Precision Mover for CTF3 Quadrupoles	quadrupole, controls, alignment, emittance	1517
	F. Toral, C. Burgos, D. Carrillo, L. García-Tabarés, J. L. Gutierrez, I. Rodriguez, E. Rodríguez García, S. Sanz, C. Vazquez CIEMAT, Madrid E. Adli, N. C. Chritin, S. Doebert, J. A. Rodriguez CERN, Geneva J. Calero CEDEX, Madrid
	A new remotely controlled moving table has been designed for the quadrupoles of the CTF3 Test Beam Line, as part of the beam based alignment system. This device must provide both vertical and horizontal (transverse to the beam) movements. The specifications request a reproducibility of ± 5 micron, with a resolution of 1 micron and a stroke of ± 4 mm. Due to the weight of the magnet, about 50 kg, and the space restrictions, a solution based on small stepping motors with integrated linear spindles has been chosen. The motor responsible of the vertical movement rests on a wedge, with a double purpose: to make the design more compact, and to increase the lifting force for a given motor size. Mechanical switches are used as end-of-movement sensors and home position detectors. The performed tests to check the mover prototype performance are also reported in this paper. Next step will be to launch series production, which will consist of 16 units.
TUPP013	Synchronized Data Distribution and Acquisition System Using Reflective Memory for J-PARC 3GeV RCS	monitoring, controls, linac, acceleration	1553
	H. Takahashi, N. Hayashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken M. Sugimoto Mitsubishi Electric Control Software Corp, Kobe
	J-PARC 3GeV RCS inject the different parameter beam to each facilities, which are MLF and MR. Therefore, 3GeV RCS Control System must realize the monitoring and the operation that are distinguished "MLF beam" from "MR beam". And, we have developed the data distribution and acquisition system for "synchronized data" which required the distinguished monitoring and operation. We have designed and developed distribution and acquisition system using Reflective Memory (RM) for BPM data, which is one of synchronized data. There are 54 BPM, and BPM signal is processed by each BPM signal circuit (total 54 circuits). Then, we have designed that RM have 54 virtual ring memories and for a few seconds BPM data pre one virtual ring memory is buffered. And we decide BPM data is written virtual ring memory position based on "beam tag", which distributed from RM of J-PARC Timing System. This "beam tag" is synchronized across J-PARC. Thereby, 54 BPM data that written same virtual ring memory position become BPM data for identical beam. The paper presents the current status of the synchronized data distribution and acquisition system using RM.
TUPP127	Spill Structure Measurements at the Heidelberg Ion Therapy Centre	synchrotron, ion, proton, controls	1824
	A. Peters, R. Cee, T. Haberer, T. Winkelmann HIT, Heidelberg T. Hoffmann, A. Reiter, M. Schwickert GSI, Darmstadt
	A specially designed accelerator facility for tumour irradiation located at the Heidelberg University Hospital was built up, the commissioning is still ongoing. Technically the Heidelberg Ion Therapy Center (HIT) fully relies on the three dimensional intensity-controlled rasterscan technique developed at GSI. This method demands for smoothly extracted ion beams (from protons to oxygen) from the HIT synchrotron. For this purpose a RF knock-out system consisting of a RF-exciter in combination with an electrostatic septum, two septum magnets and two sextupoles is used. To characterize the extracted beams scintillators for low intensities and ionization chambers for higher currents are installed in the high energy transport lines. Using a PXI-based DAQ system full spills are recorded with a time bin of 100 μs. Typical raw data will be shown as well as derived statistics like Fourier spectra and maximum-to-average ratios that proof the beam quality for its applicability to produce outstanding dose distributions via beam scanning. In addition, safety aspects like the performance of the spill interrupt procedure will be demonstrated with measured data.
WEOAG02	Measurements of Heavy Ion Beam Losses from Collimation	ion, simulation, proton, collimation	1906
	R. Bruce, R. W. Assmann, G. Bellodi, C. Bracco, H.-H. Braun, S. S. Gilardoni, E. B. Holzer, J. M. Jowett, S. Redaelli, Th. Weiler, C. Zamantzas CERN, Geneva
	The collimation efficiency for Pb82+ ion beams in the LHC is predicted to be much lower than for protons. Nuclear fragmentation and electromagnetic dissociation in the primary collimators create fragments with a wide range of Z/A ratios, which are not intercepted by the secondary collimators but lost where the dispersion has grown sufficiently large. In this article we present measurements of loss patterns caused by a prototype LHC collimator in the CERN SPS. The loss maps show a qualitative difference between Pb82+ ions and protons, with the maximum loss rate observed at different places in the ring. This behaviour was predicted by simulations and provides a valuable benchmark of the simulations done for the LHC.
	Slides
WEOBG01	CLIC RF High Power Production Testing Program	damping, recirculation, target, linac	1909
	I. Syratchev, G. Riddone CERN, Geneva S. G. Tantawi SLAC, Menlo Park, California
	The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production (~ 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses make the PETS design rather unique and the operation very challenging. In coming years the intensive PETS testing program will be implemented. The target is to demonstrate full performance of the PETS operation. The testing program overview and test results available to date will be presented.
	Slides
WEOCG02	Post-mortem Diagnostic for the Taiwan Light Source	kicker, diagnostics, insertion, controls	1932
	K. H. Hu, J. Chen, P. C. Chiu, K. T. Hsu, S. Y. Hsu, C. H. Kuo, D. Lee, C.-J. Wang, C. Y. Wu NSRRC, Hsinchu
	Analyzing the reasons of various trip events is essential to improve reliability of a synchrotron light source. To identify the causes of trip at Taiwan Light Source (TLS), various diagnostics tool were employed. These diagnostic tools can capture beam trip, interlock signals of superconducting RF system, waveform of the injection kickers, quench and interlock signals of the superconducting insertion device, and instability signals of the stored beam for post-mortem analysis. These diagnostics can be routine monitor signal and record beam trip event. Features of trip diagnostic tools are available now. System configuration experiences will be summarized in this report.
	Slides
WEPC092	A Pulsed Quadrupole Magnet Injection at the PF-AR Storage Ring	injection, dipole, quadrupole, factory	2207
	H. Takaki, N. Nakamura ISSP/SRL, Chiba K. Harada, Y. Kobayashi, T. Miyajima, S. Nagahashi, T. Obina, A. Ueda, K. Umemori KEK, Ibaraki
	We have examined a beam injection system that used a pulsed quadruple magnet (PQM) at the PF-AR storage ring since the spring of 2004. The system is operating well and the accumulation of the beam up to 60mA in the single bunch operation is possible by the current state. The beam injection system that uses the PQM does not require a conventional injection bump orbit, and has the feature that only one PQM in the injection part is needed. An injected beam is kicked to be proportional to the distance from the center and captured afterwards. On the other hand, the pulse kick hardly influences the stored beam at the magnetic field center of the PQM. We report on the result of collecting the basic data of the influence on the PQM beam injection at the PF-AR storage ring.
WEPC137	Design of Two Variable Polarization Undulators for the ALBA Project	undulator, controls, polarization, power-supply	2329
	D. Zangrando, R. Bracco, B. Diviacco, D. La Civita, M. Musardo, G. Tomasin ELETTRA, Basovizza, Trieste F. Becheri, J. Campmany, C. Colldelram, D. Einfeld, J. V. Gigante ALBA, Bellaterra Z. Martí LLS, Bellaterra (Cerdanyola del Vallès)
	This paper summarizes the main aspects of the magnetic, mechanical and control system design of two APPLE-II type undulators presently under construction in the framework of a collaboration between CELLS and Sincrotrone Trieste.
WEPC157	A Hybrid Quadrupole Design for the RAL Front End Test Stand (FETS)	quadrupole, simulation, permanent-magnet, proton	2377
	D. C. Plostinar, M. A. Clarke-Gayther STFC/RAL/ASTeC, Chilton, Didcot, Oxon P. Davis STFC/RAL, Chilton, Didcot, Oxon S. J.S. Jago STFC/RAL/ISIS, Chilton, Didcot, Oxon
	The Front End Test Stand project being constructed at Rutherford Appleton Laboratory (RAL) aims to deliver a high current (60 mA) H- chopped ion beam, at 3 MeV and 50 pps. The main components of FETS are the H- ion source, the Low Energy Beam Transport line (LEBT), the Radio Frequency Quadrupole (RFQ) and the Medium Energy Transport (MEBT) line with beam chopper. Space restrictions in the MEBT line place constraints on component length and drive the requirement to identify compact component configurations. A description is given of a novel compact hybrid quadrupole magnet, whose design is based on the concentric combination of a permanent magnet quadrupole (PMQ) and a laminar conductor electromagnetic quadrupole (EMQ). Simulations of magnetic field distribution in 2 and 3D are presented, and possible applications and further developments are discussed.
WEPP006	Effects of Ultraperipheral Nuclear Collisions in the LHC and their Alleviation	ion, simulation, collimation, luminosity	2533
	R. Bruce, S. S. Gilardoni, J. M. Jowett CERN, Geneva
	Electromagnetic interactions between colliding heavy ions at the LHC are the sources of specific beam loss mechanisms that may quench superconducting magnets. We propose a simple yet efficient strategy to alleviate the effect of localized losses from bound-free pair production by spreading them out in several magnets by means of orbit bumps. We also consider the consequences of neutron emission by electromagnetic dissociation and show through simulations that ions modified by this process will be intercepted by the collimation system, without further modifications.
WEPP061	A Position Monitor for the Aborted Beam in KEKB	kicker, septum, diagnostics, electron	2659
	N. Iida, M. Kikuchi, T. Mimashi, K. Mori, M. Tejima KEK, Ibaraki
	The beams in the KEKB rings are aborted by abort kickers, Lambertson septums and dumps. First the beams are kicked by the abort kickers rapidly in the horizontal direction to outside the beam pipe and are bent slowly in the vertical direction. At the same time horizontal magnetic fields shake the beam to protect the abort window where the kicked beam passes and protect the window from heat by the high current beam. A beam position monitor is installed in front of the dump. We can get some informations of aborted beam by the monitor. In this paper a method for monitoring the beam in the high energy ring at KEKB is described.
WEPP069	Tracking Tools to Estimate the Quench Time Constants for Magnet Failures in LHC	simulation, insertion, superconducting-magnet, proton	2677
	A. Gomez Alonso CERN, Geneva
	At LHC, beam losses, with about 360MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment and can also affect the operational efficiency by inducing quenches in superconducting magnets. Magnet failures may affect the beam leading to proton losses primarily in collimators and secondary in superconducting magnets due to scattering of protons from collimator jaws. The evolution of the beam during magnet failures has been simulated using MAD-X with a variable magnetic field. The impacts of particles in the collimators have been recorded as a function of time. A second program, CollTrack, has been used to determine the loss patterns of scattered particles from each collimator as a function of the initial impact parameter. The magnets that are likely to quench are identified and an estimation of the time between the beginning of a failure and a quench is obtained by combining the results from the simulations. The time to a start of a quench is a relevant parameter to determine the dump threshold of beam loss monitors in order to optimize protection redundancy and operation smoothness for LHC.
WEPP072	Evaluation of Beam Losses and Energy Deposition for A Possible Phase II Design for LHC Collimation	simulation, collimation, proton, kicker	2686
	L. Lari, R. W. Assmann, C. Bracco, M. Brugger, F. Cerutti, A. Ferrari, M. Mauri, S. Redaelli, L. Sarchiapone, V. Vlachoudis, Th. Weiler CERN, Geneva J. E. Doyle, L. Keller, S. A. Lundgren, T. W. Markiewicz, J. C. Smith SLAC, Menlo Park, California L. Lari EPFL, Lausanne
	The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.
WEPP079	Beam Dynamics Layout and Loss Studies for the FAIR P-Injector	quadrupole, emittance, proton, linac	2701
	G. Clemente, L. Groening GSI, Darmstadt S. Minaev ITEP, Moscow U. Ratzinger, R. Tiede IAP, Frankfurt am Main
	The development of coupled CH-DTL cavities represents a major achievement in the development of the 325 MHz, 70 MeV FAIR P-Injector. This coupled-cavity solution has important consequencies on the beam dynamics design which has to be adapted to this new kind of resonator. In combination with the KONUS beam dynamics, this solution allows to achieve all the requirements of the FAIR project in terms of beam intensity and quality reducing at the same time the number of focusing elements along the machine. A layout based on 6 CH coupled modules is presented and compared with a solution composed of three coupled modules up to 35 MeV followed by three long single resonators up to the energy of 70 MeV. A redesigned 35 MeV intertank section became necessary to avoid beam losses and emittance growth. Finally, the effect of random mistakes such as quadrupole misalignments and phase as well as voltage setting errors have been investigated to determine the tolerances of mechanical construction and rf controls during operation.
WEPP110	Design and Operational Experience of the MICE Target	target, insertion, injection, acceleration	2764
	C. N. Booth, P. Hodgson, L. C. Howlett, M. T. Mohammad, R. Nicholson, P. J. Smith Sheffield University, Sheffield N. Schofield University of Manchester, School of Electrical and Electronic Engineering, Manchester
	The MICE experiment requires a beam of low energy muons to test muon cooling. This beam will be derived parasitically from the ISIS synchrotron. A novel target mechanism has been developed which allows the insertion of a small titanium target into the proton beam halo on demand. The target must remain outside of the beam envelope during acceleration, and then overtake the beam during the last 2ms before extraction. The technical specifications are demanding, and require large accelerations and precise and reproducible location of the target in each cycle. The mechanism must also operate in a high radiation environment, and the moving parts and materials must be compatible with the stringent requirements of operating in a working accelerator. The design, and the commissioning and operational experience using this system during the first operating periods in 2008 is described.
THXG01	SNS Progress, Challenges and Upgrade Options	linac, target, injection, beam-transport	2892
	S. Henderson ORNL, Oak Ridge, Tennessee
	The talk describes the progress of SNS towards 1 MW, includes discussion of the challenges of successfully running high power superconducting pulsed proton linacs, and also looks forward to upgrade programmes.
	Slides
THXG02	J-PARC Progress and Challenges of Proton Synchrotrons	linac, proton, injection, acceleration	2897
	M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	After briefly outlining the status of the J-PARC linac, the talk should concentrate on describing the outcome of the 3 GeV J-PARC synchrotron commissioning programme, and also include discussion of the challenges of successfully running high power proton synchrotrons.
	Slides
THYM02	Incoherent Effects of Space Charge and Electron Cloud	resonance, incoherent-effects, emittance, space-charge	2942
	G. Franchetti, I. Hofmann GSI, Darmstadt F. Zimmermann CERN, Geneva
	Trapping in, or scattering off, resonances driven by space charge or electron cloud in conjunction with synchrotron motion can explain numerous observations of slow beam loss and emittance growth, which are often accompanied by changes in the longitudinal beam profile. This talk will review recent progress in understanding and modelling the underlying mechanisms, highlight the differences and similarities between space charge and electron cloud, and discuss simulation results in the light of experimental observations, e.g., at GSI, CERN and BNL.
	Slides
THPC017	Optimisation of a Beam Transfer FODO Line	quadrupole, vacuum, optics, emittance	3014
	J. B. Jeanneret, H.-H. Braun CERN, Geneva
	With in view the design of the CLIC long transfer lines, we developed a formal approach for the optimisation of a straight FODO line. Optimum phase advance and cell length depending on beam parameters are derived for power consumption, overall cost and sensitivity to quadrupole misalignment.
THPC036	Model Based Orbit Correction in a Diagnostics Deficient Region	linac, controls, dipole, diagnostics	3056
	A. P. Shishlo, A. V. Aleksandrov ORNL, Oak Ridge, Tennessee
	A method is presented for an orbit correction in a region where the number of beam position monitors is much less than the number of possible trajectory distortions points (quads). The method was developed for the Coupled Cavities Linac (CCL) part of the Spallation Neutron Source (SNS) linac. The orbit correction is very important in this region to minimize losses and activation, but the usual orbit correction method did not work here. The new method is based on a usage of a realistic online model. The parameters of the model were defined by multidimensional fitting procedure with a substantial array of measured trajectories in CCL. The procedure of parameters finding, model, and results are discussed.
THPC048	Study of Beam Losses at Transition Crossing at the CERN PS	quadrupole, optics, proton, dipole	3086
	S. S. Gilardoni, S. Aumon, M. Martini CERN, Geneva
	A series of studies has been carried out to understand and alleviate the beam losses in the CERN PS proton Synchrotron. In particular, losses appear at transition crossing during the pulsing of special quadrupoles used to create a gamma jump scheme and which causes a large optics and orbit distortion. After a brief summary of the gamma jump scheme at the PS, experimental and simulation results about the loss studies and reduction are presented.
THPC052	Beam Losses and Collimation Considerations for PS2	collimation, injection, extraction, lattice	3098
	J. Barranco, W. Bartmann, M. Benedikt, Y. Papaphilippou CERN, Geneva
	The high intensity beams with different emittances foreseen to be delivered by the PS2, an upgraded version of the actual CERN Proton Synchrotron, require strict control of beam losses in order to protect the machine components and enable their hands-on maintenance. Beam loss simulations based on dedicated numerical tools are undertaken for a variety of PS2 beams and for different loss mechanisms, along the whole accelerating cycle. In this respect, the design of a collimation system is presented and its performance is compared within different lattice options.
THPC059	Studies of Wire Compensation and Beam-beam Interaction in RHIC	simulation, emittance, dynamic-aperture, luminosity	3119
	H. J. Kim, T. Sen Fermilab, Batavia, Illinois N. P. Abreu, W. Fischer BNL, Upton, Long Island, New York
	Beam-beam interaction is one of the dominant source of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and the principle is now being experimentally investigated at RHIC. In this paper, we use simulations to study the effectiveness of wire compensation based on tune footprints, diffusive apertures, and beam loss rates using a parallel weak-strong beam simulation code (BBSIM). In addition we extensively study the diffusion properties of RHIC beams for different beam and wire parameters. Beam-beam effects on emittance growth are investigated through the solution of the diffusion equation for the transverse action variables.
THPC066	Measuring Ring Nonlinear Components via Induced Linear "Feed-down"	sextupole, resonance, simulation, closed-orbit	3137
	A. S. Parfenova, G. Franchetti, I. Hofmann GSI, Darmstadt
	The knowledge of the distribution in a ring of the non-linear components is important for the resonance compensation. We present a method to measure the lattice nonlinear components based on the non-linear tune response to a locally controlled closed orbit deformation. A test of this concept in the SIS18 synchrotron is presented and discussed.
THPC082	Wire Excitation Experiments in the CERN SPS	simulation, coupling, optics, resonance	3176
	U. Dorda, J.-P. Koutchouk, R. Tomas, J. Wenninger, F. Zimmermann CERN, Geneva R. Calaga, W. Fischer BNL, Upton, Long Island, New York
	In order to study the effect of long range interaction and its wire compensation experimentally, current carrying wires are installed in the CERN Super Proton Synchrotron (SPS). In this paper we summarize the main results of the 2007 wire excitation results at 26, 37 and 55 GeV including wire-current-, beam-wire distance and chromaticity scans. A strong dependence on the chromaticity and indications of a threshold effect at 37 and 55 GeV was found. The results are compared to simulation, to a simple analytic scaling law and to experimental results from RHIC. Wire-driven resonances have been observed through the Fourier spectrum of experimental BPM data and compared to simulations.
THPC088	Beam Dynamics Simulation of Superconducting HWR Option for the IFMIF Linac	linac, simulation, rfq, emittance	3194
	N. Chauvin, A. Mosnier, P. A.P. Nghiem, D. Uriot CEA, Gif-sur-Yvette
	One of the requirements of the International Fusion Materials Irradiation Facility (IFMIF) is a 250 mA, 40 MeV cw deuteron beam provided by two 125 mA linacs. In this paper, a design based on superconducting half-wave resonators (HWR) for the 5 to 40 MeV section of the IFMIF driver accelerator is presented. Multi particle beam dynamics simulations have been performed in order to validate the linac design in such a high charge space regime. A Monte Carlo error analysis has been carried out to study the effects of misalignments or field variations. The results of the simulations are presented and the final specifications of the HWR linac are summarized.
THPC112	KONUS Dynamics and H-mode DTL Structures for EUROTRANS and IFMIF	focusing, simulation, rfq, linac	3239
	C. Zhang, M. Busch, H. Klein, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main
	During the last two decades, the combination of the KONUS beam dynamics and H-mode DTL structures has been developed as an efficient solution for accelerating low- and medium-energy proton and ion beams. EUROTRANS is a EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator Driven System. IFMIF is a planned International Fusion Material Irradiation Facility to test materials for fusion reactors. For the driver linacs of both projects, two H-DTLs have been proposed to cover the energy ranges of 3–17MeV and 5–40MeV, respectively. The beam dynamics designs as well as the error studies of the H-DTLs are presented in this paper.
THPC142	The Operation Event Logging System of the SLS	feedback, controls, linac, radio-frequency	3318
	A. Luedeke PSI, Villigen
	Modern 3rd generation synchrotron light sources aim for 100% availability. No single beam interruption is acceptable and every distortion of operation should be investigated: What caused the interruption? Can it be avoided in the future? If it can't be avoided, how can the recovery be accelerated? An automated event recording system has been implemented at the Swiss Light Source (SLS) in order to simplify this investigations. The system identifies distortions of the user operation and records automatically type and duration of the event. All relevant information connected to the event, from control system archive data to shift protocols, is linked to the event and presented in web pages. Additional information can be added manually. Each event will be assigned to a failure cause and area. Means to filter the events are provided. The paper will describe the concept and implementation of the even logging system at the SLS and the experiences with the system.
THPC145	Reliability Analysis of the LHC Machine Protection System: Terminology and Methodology	injection, simulation, hadron, diagnostics	3327
	S. Wagner Swiss Federal Institute of Technology Zurich (ETH), Laboratory for Safety Analysis, Zurich R. Schmidt, J. Wenninger CERN, Geneva
	The trade-off between LHC machine safety and beam availability is one of the main issues related to the LHC MPS. Several studies have addressed it for different subsystems. They are followed by a project aiming at the development of a methodology which combines agent-based modeling and fault-tree analysis thus allowing a global analysis of the entire MPS. During this project, the need for a clarification and specification of the terminology has become apparent. Besides involving basic terms like safety, reliability and availability, the analysis must take into account the implementation of common design principles such as redundancy, fault tolerance, 'fail-safe' and self-monitoring. These terms and in particular their interrelations easily cause confusion. Since the traceability of the analysis depends on a consistent understanding of the underlying terminology, a terminology frame is being compiled. The paper specifies the most relevant terms and their interrelations. General standard definitions are taken as basis for a specification related to the MPS and its analysis respectively. The developed analysis methodology building on this terminology frame is introduced.
THPC147	Generation of 1.5 Million Beam Loss Threshold Values	proton, simulation, insertion, collimation	3333
	E. B. Holzer, B. Dehning, L. Ponce, M. Sapinski, M. Stockner CERN, Geneva D. K. Kramer TUL, Liberec P. Priebe Poznan University of Technology, Poznan
	CERN's Large Hadron Collider will store an unprecedented amount of energy in its circulating beams. Beam-loss monitoring (BLM) is, therefore, critical for machine protection. It must protect against the consequences (equipment damage, quenches of superconducting magnets) of excessive beam loss. 4000 monitors will be installed at critical loss locations. Each monitor has 384 beam abort thresholds associated; for 12 integrated loss durations (40 us to 83 s) and 32 energies (450 GeV to 7 TeV). Depending on monitor location, the thresholds vary by orders of magnitude. For simplification, the monitors are grouped in 'families'. Monitors of one family have the same thresholds at start-up; they protect similar magnets against equivalent loss scenarios. The start-up calibration of the BLM system is required to be within a factor of five in accuracy; and the final accuracy should be a factor of two. Simulations (backed-up by control measurements) determine the relation between the BLM signal, the deposited energy and the critical energy deposition for damage or quench (temperature of the coil). The paper presents the details and systematic of determining 1.5 million threshold values.
THPC149	Beam Scraping to Detect and Remove Halo in LHC Injection	simulation, injection, proton, controls	3339
	P. A. Letnes, S. Bart Pedersen, A. Brielmann, H. Burkhardt, D. K. Kramer CERN, Geneva
	Fast scrapers are installed in the SPS to detect and remove beam halo before extraction of beams to the LHC, to minimize the probability for quenching of super-conducting magnets in the LHC. We shortly describe the current system and then focus on our recent work, which aims at providing a system which can be used as operational tool for standard LHC injection. A new control application was written and tested with the beam. We describe the current status and results and compare these with detailed simulations.
THPP044	Experience with the SNS SC Linac	linac, emittance, focusing, beam-transport	3461
	Y. Zhang, A. V. Aleksandrov, C. K. Allen, I. E. Campisi, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, S.-H. Kim, T. A. Pelaia, A. P. Shishlo ORNL, Oak Ridge, Tennessee
	The SNS SC linac (SCL) is designed to deliver 1 GeV, up to 1.56 MW pulsed H- beams for neutron production. Beam commissioning of the SNS accelerator systems completed in June 2006 with the maximum linac output beam energy approximately 952 MeV. In 2007, we successfully tuned the SCL for 1 GeV beams during a test run, and the SNS linac achieved its design energy for the first time. During the linac tune-up, phase scan signature matching, drifting beam measurement as well as linac RF cavity phase scaling was applied. In this paper, we will introduce the experiences with the SCL, and we will also briefly discuss beam parameter measurements.
THPP073	Performance of the SNS Front End and Warm Linac	linac, target, kicker, radiation	3530
	A. V. Aleksandrov, C. K. Allen, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, T. A. Pelaia, M. A. Plum, A. P. Shishlo, M. P. Stockli, Y. Zhang ORNL, Oak Ridge, Tennessee
	The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector, capable of producing one-ms-long pulses at 60 Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5 MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. With the completion of beam commissioning, the accelerator complex began operation in June 2006 and beam power is being gradually ramped up toward the design goal. Operational experience with the injector and linac will be presented including chopper performance, longitudinal beam dynamics study, and the results of a beam loss study.
THPP075	Beam Dynamics of the IFMIF-EVEDA RFQ	rfq, emittance, focusing, multipole	3536
	M. Comunian, A. Pisent, P. A. Posocco INFN/LNL, Legnaro, Padova E. Fagotti Consorzio RFX, Euratom ENEA Association, Padova
	The IFMIF project is aimed at the realization of an intense neutron beam facility for testing the irradiation of the materials to be used for fusion reactors. EVEDA (Engineering Validation Engineering Design Activities) is a first step towards the implementation of this challenging project and consists of the construction of prototypes of the main units. In particular INFN-LNL is in charge of the construction of a 5 MeV, 125 mA, deuteron RFQ at 175 MHz. In this article the main aspects of the beam dynamics design of this RFQ are described, namely the optimization of the length and the transmission issues, the main outcomes and comparison of the PARMTEQM and TOUTATIS codes used for the simulations and the basic aspects of the errors studies.
THPP078	IFMIF-EVEDA RFQ Design	rfq, coupling, simulation, vacuum	3542
	A. Pisent, M. Comunian, E. Fagotti, A. Palmieri, P. A. Posocco, C. Roncolato INFN/LNL, Legnaro, Padova F. Grespan Università degli Studi di Milano, Milano A. Pepato INFN- Sez. di Padova, Padova
	The RFQ of IFMIF-EVEDA project is characterized by very challenging specifications, with 125 mA of deuteron accelerated up to 5 MeV. After the long period of conceptual and comprehensive design of IFMIF accelerator, the decision of the construction of its low energy part has implied a new analysis of the RFQ design. In particular the beam dynamics design has been optimized, with a consistent reduction of the structure length and power consumption, and improvement of the performances in terms of beam losses. The resonator, of four vanes kind, has been designed taking advantage of the theoretical background and experimental experience gained in Europe with IPHI and TRASCO projects. The mechanical design has been analysed considering different approaches, involving vacuum brazing, laser or e'beam welding.
THPP080	A Superconducting CH-Linac for IFMIF	linac, rfq, acceleration, focusing	3548
	H. Podlech, A. Bechtold, M. Busch, F. Dziuba, H. Klein, H. Liebermann, U. Ratzinger, R. Tiede, C. Zhang IAP, Frankfurt am Main
	The IFMIF accelerator which has to provide a 40 MeV 250 mA Deuteron beam requires a duty cycle of 100%. The IAP Frankfurt has proposed 175 MHz H-type drift tube linac consisting of an IH-cavity and a chain of superconducting CH-cavities. A superconducting CH-prototype cavity has been tested very successfully and reached effective gradients of 7 MV/m. Two rf power couplers are necessary to feed one CH-cavity. The maximum rf power per cavity is approximately 500 kW. As amplifiers the originally foreseen 1 MW tubes or 300 kW tubes can be used. The focusing scheme in the CH-linac is based on superconducting solenoids. Beam dynamics simulations have been performed with an error analysis using the LORASR code based on the KONUS dynamics. An updated and improved linac design will be presented. A contribution of IAP for the EVEDA phase could consists of the construction and the test of the room temperature IH-cavity and the first complete CH cryo-module. A study together with industry has been already performed regarding the production process and the system integration of auxiliary equipment like couplers and tuner.
THPP082	Residual Activity Induced by High-energy Heavy Ions in Stainless Steel and Copper	ion, target, proton, simulation	3551
	I. Strasik, I. Hofmann, E. Kozlova, E. Mustafin GSI, Darmstadt L. N. Latysheva, N. Sobolevskiy RAS/INR, Moscow M. Pavlovic STU, Bratislava A. Smolyakov ITEP, Moscow
	The activation of accelerator structures due to beam loss is already intensity limiting problem for existing (SNS or RHIC) and planned (LHC or FAIR) hadron facilities. While beam-losses of 1 W/m are recognized as a tolerable beam-loss level for proton machines, the beam-loss tolerances for high-power heavy-ion accelerators have not yet been quantified. In this work the residual activity was calculated by Monte-Carlo particle transport codes and compared with experimental data. Simulations were performed for projectiles from proton to uranium. Experiments were performed with uranium ions at 120, 500 and 950 MeV/u irradiating copper and stainless steel targets. It was found that the isotope inventory contributing over 90% to the total activity does not depend on the projectile species, it depends only on the target material and projectile energy. This allowed establishing a scaling law for induced activity as a function of ion mass. The activity per nucleon induced by ion scales down with increasing ion mass. For example, 1 GeV/u uranium ion induces 5-times less activity per nucleon compared to 1 GeV proton. The beam-loss criteria for different projectile species are presented.
THPP084	Discussion on RCS versus AR on the Basis of J-PARC Beam Commissioning for Pulsed Spallation Neutron Source	injection, linac, proton, space-charge	3557
	Y. Yamazaki KEK/JAEA, Ibaraki-Ken M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	Over a decade it is one of the most controversial issues regarding the accelerator scheme choice whether RCS or AR should be chosen for the pulsed spallation neutron source. In order to simplify the discussion, we compare 3-GeV RCS with 1-GeV AR. The former is J-PARC scheme while the latter is SNS scheme. To summarize the discussion, RCS technology is much more difficult than AR technology, although RCS has many advantages over AR arising from its low beam current for the same beam power. Now, the J-PARC 3-GeV RCS was actually commissioned. On the basis of its experience, the discussion will be resumed.
THPP085	Status of the SNS Ring Power Ramp Up	target, injection, extraction, linac	3560
	M. A. Plum, A. V. Aleksandrov, C. K. Allen, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, T. A. Pelaia, A. P. Shishlo, Y. Zhang ORNL, Oak Ridge, Tennessee
	Beam was first circulated in the SNS ring in January 2006. Since that time we have been working to raise the beam power to the design value of 1.4 MW. In general the power ramp up has been proceeding very well, but several issues have been uncovered. Examples include poor transmission of the waste beams in the injection dump beam line, cross-plane coupling in the ring to target beam transport line, and higher-than-expected peak densities in the ring to target transport. In this paper we will discuss these issues and present an overall status of the ring and the transport beam lines.
THPP086	Diamond Stripper Foil Experience at SNS and PSR	target, injection, plasma, electron	3563
	R. W. Shaw, Y.-J. Chen, R. L. Coleman, D. M. Gardner, C. Luck, A. G. McDermott, M. A. Plum, L. L. Wilson ORNL, Oak Ridge, Tennessee M. J. Borden, T. Spickermann LANL, Los Alamos, New Mexico C. S. Feigerle University of Tennessee, Knoxville, Tennessee
	The SNS is currently operating at about 15% of the 1.4 MW design power, and the diamond stripper foils developed at ORNL continue to perform well. Several corrugated, nanocrystalline diamond stripping foils have been tested at SNS. Beyond about 300 C of injected charge, significant distortion and darkening of the foils is observed. These foils are currently limited in freestanding area to about 17x25 mm due to stress-induced tears in larger foils; this limit positions the residual silicon wafer mounting handle close enough to the circulating beam that additional losses have been observed. The PSR experience with these diamond foils has been promising, with the interesting observation that both the foil current due to secondary emission of electrons and the thermionic foil current are reduced for diamond foils relative to LANL/KEK foils. For comparable thickness foils, losses due to the Ho yield also appear to be higher for diamond. A recent development in our foil preparation has been a change to nano-seeded nucleation from the earlier microcrystal slurry ultrasonic abrasion technique. This has led to a more reproducible and uniform foil morphology with smaller crystallites.
THPP102	Radiation Damage Studies for the Slow Extraction from SIS100	quadrupole, extraction, septum, ion	3602
	A. Smolyakov ITEP, Moscow E. Mustafin, N. Pyka, P. J. Spiller GSI, Darmstadt
	During the slow extraction from SIS100 synchrotron 5% of the beam will hit the wires of the electrostatic septum and will be lost. These losses produce very high radiation damage to the superconducting quadrupole doublet situated downstream of the extraction point. These beam losses were simulated with the help of Fluka code for U28+ and Ne5+ beams. Non-zero cross-section and non-zero angular divergence were assumed for the lost beam, allowing distributed modeling of the slow extraction losses. The radiation damage to different layers of the superconducting quadrupole cables was calculated. The lifetime of the s.c. cables of the quadrupoles was found to be too short. Thus, alternative quadrupole designs with higher radiation tolerances were investigated: with stainless steel shielding of the s.c. cables and with a gap in the mid-plane between the s.c. cables.
THPP106	Neutrino Beam Line at J-PARC	target, proton, focusing, controls	3614
	M. Shibata KEK, Tsukuba
	A neutrino beam line for the long baseline neutrino oscillation experiment T2K is under construction at J-PARC in Tokai. Construction is proceeding on schedule and commissioning of the beam line will start in April of 2009. Proton beams are injected from the main ring, then bent about 80 degrees using superconducting magnets directing the beam toward the Super-Kamiokande detector. Muon neutrinos are produced from pions produced at the target. Precise beam tuning is quite important in our beam line since the beam intensity is expected to be 750 kW and failure of the tuning system may cause damage to the beam line components. For this purpose, we install four types of beam monitors in the primary beam line: CT for beam intensity, ESM for beam position, SSEM for beam profile and a loss monitor. Specifications and current status of these monitors will be reported. We report also on ground motion in the facility. Since the floor level of the neutrino beam line was observed to sink after initial construction, a level meter was installed to observe the motion continuously as it could be a serious problem for beam line alignment.
THPP127	ATF2 High Availability Power Supplies	power-supply, controls, diagnostics, monitoring	3658
	B. Lam, P. Bellomo, D. J. MacNair, G. R. White, A. C. de Lira SLAC, Menlo Park, California V. R. Rossi O. C.E. M. S.p. A., S. Giorgio di Piano
	ATF2 is an accelerator test facility modeled after the final focus beamline envisioned for the ILC. By the end of 2008, KEK plans to commission the ATF2. SLAC and OCEM collaborated on the design of 38 power systems for beamline magnets. The systems range in output power from 1.5 kW to 6 kW. Since high availability is essential for the success of the ILC, Collaborators employed an N+1 modular approach, allowing for redundancy and the use of a single power module rating. This approach increases the availability of the power systems. Common power modules reduces inventory and eases maintenance. Current stability requirements are as tight as 10 ppm. A novel, SLAC-designed 20-bit Ethernet Power Supply Controller provides the required precision current regulation. In this paper, Collaborators present the power system design, the expected reliability, fault immunity features, and the methods for satisfying the control and monitoring challenges. Presented are test results and the status of the power systems.
THPP145	Machine Operation Issues Related to the Vacuum System of the ESRF	vacuum, undulator, cryogenics, storage-ring	3705
	R. Kersevan, M. Hahn, I. Parat, D. Schmied ESRF, Grenoble
	This paper deals with various operational issues related to the vacuum system of the ESRF storage ring. The impact on the vacuum pressure, beam lifetime, beam losses and other machine parameters after installation of new chambers, diagnostics, RF cavities and insertion devices, and vacuum leaks is discussed in some detail. Particular emphasis is given to the behaviour of the prototype of a 2m-long cryogenic in-vacuum undulator, a new RF cavity, and NEG-coated chambers. Lessons learned from the operation of these and other vacuum components will be extended to the proposed machine upgrade.