IPAC2011 - List of Keywords (feedback)

Paper	Title	Other Keywords	Page
MOODA02	S1-Global Module Tests at STF/KEK	cavity, cryomodule, SRF, linac	38
	D. Kostin, K. Jensch, L. Lilje, A. Matheisen, W.-D. Möller, P. Schilling, M. Schmökel, N.J. Walker, H. Weise DESY, Hamburg, Germany C. Adolphsen, C.D. Nantista SLAC, Menlo Park, California, USA M. Akemoto, S. Fukuda, K. Hara, H. Hayano, N. Higashi, E. Kako, H. Katagiri, Y. Kojima, Y. Kondo, T. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakai, H. Nakajima, K. Nakanishi, S. Noguchi, N. Ohuchi, T. Saeki, M. Satoh, T. Shidara, T. Shishido, T. Takenaka, A. Terashima, N. Toge, K. Tsuchiya, K. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, K. Yokoya KEK, Ibaraki, Japan T.T. Arkan, S. Barbanotti, M.A. Battistoni, H. Carter, M.S. Champion, A. Hocker, R.D. Kephart, J.S. Kerby, D.V. Mitchell, T.J. Peterson, Y.M. Pischalnikov, M.C. Ross, W. Schappert, B.E. Smith Fermilab, Batavia, USA A. Bosotti, C. Pagani, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy
	S1-Global collaborative effort of INFN, DESY, FNAL, SLAC and KEK, recently successfully finished at KEK as a part of ILC GDE, is an important milestone for the ILC. International collaboration of three regions, Asia, North America and Europe, proved to be efficient on the construction and cold tests of the accelerating module consisting of 8 SRF cavities; 2 from FNAL, 2 from DESY and 4 from KEK. Three different cavity tuning systems were tested together with two types of high power couplers. The module was cooled down three times which enabled extensive high power tests with cavities, performance limits investigation, Lorentz force detuning tests, simultaneous multiple cavities operation and other activities such as an operation test of distributed RF scheme with low level RF feedback. The results of this S1-Global module test are presented and discussed.
	Slides MOODA02 [2.982 MB]

MOPC077	Commissioning of Multibunch Feedback Systems at the Fast Ramping Stretcher Ring ELSA	kicker, synchrotron, cavity, booster	250
	A. Roth, F. Frommberger, N. Heurich, W. Hillert, M. Schedler, R. Zimmermann ELSA, Bonn, Germany
	Funding: Supported by German Research Foundation through SFB/TR 16 and by Helmholtz Alliance through HA-10¹. At the Electron Stretcher Facility ELSA of Bonn University, an external beam of either unpolarized or polarized electrons is supplied to hadron physics experiments. The ELSA stretcherring operates in the energy range of 1.2 to 3.5 GeV and achieves a duty cycle of up to 80% using a fast energy ramp of 4 GeV/s. Under these conditions, an increase of the internal beam current from an actual value of 20 mA up to 200 mA is planned. Such an upgrade is mainly limited by the excitation of multibunch instabilities. As one active counteraction, we have installed state-of-the-art bunch-by-bunch feedback systems for the longitudinal, as well as for both transverse planes. The detailed setup with all main components and first results of the commissioning of the systems will be presented. In particular, the performance of the longitudinal feedback with a stabilized synchrotron frequency during the fast energy ramp will be discussed.

MOPC146	Development of Timing Distribution System with Femto-second Stability	linac, controls, acceleration, laser	421
	T. Naito, K. Ebihara, S. Nozawa, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan M. Amemiya AIST, Tsukuba, Japan
	A timing distribution system with femto-second stability has been developed for the RF synchronization of accelerator and the laser synchronization of the pump-probe experiments. The system uses a phase stabilized optical fiber(PSOF) and an active fiber length stabilization. The PSOF has 5 ps/km/degC of the temperature coefficient. The active fiber length stabilization uses the phase detection of the round-trip sinusoidal wave and the fiber stretcher for the compensation of the fiber length. In this paper, we present the test results on a 500 m long signal distribution. The preliminary results of the timing stability are 20 fs at several minutes and 100 fs at four days, respectively.

MOPC148	Optical Clock Distribution System at the ALICE Energy Recovery Linac	pick-up, laser, electron, FEL	427
	T.T. Ng, S.P. Jamison STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Highly stable clock distribution across future light sources is important for the synchronisation of beam generation, manipulation and diagnostics with photon experiments. Optical fibre technology can be used to combat the stability challenges in distributing clock signals over long distances with coaxial cable. We report here on the status of the optical clock distribution system installed on the ALICE energy recovery linac which uses the propagation of ultra-short optical pulses to carry the clock signal. We also present the characterisation of a beam arrival monitor suitable using <40 pC bunch charges and 7 mW, sub-100 fs distributed clock pulses.

MOPC154	RF Photo Gun Stability Measurement at PITZ	gun, laser, cavity, electron	442
	I.I. Isaev, H.-J. Grabosch, M. Gross, L. Hakobyan, Ye. Ivanisenko, G. Klemz, W. Köhler, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, F. Stephan, G. Vashchenko, S. Weidinger, R.W. Wenndorff DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria M. Hoffmann, H. Schlarb DESY, Hamburg, Germany M.A. Khojoyan YerPhI, Yerevan, Armenia D. Richter HZB, Berlin, Germany A. Shapovalov NRNU MEPHI, Moscow, Russia I.H. Templin, I. Will MBI, Berlin, Germany
	The stability of the RF phase in the RF photo injector gun is one of the most important factors for the successful operation of linac based free-electron lasers. Instabilities in the RF launch phase can significantly reduce the beam quality. Investigation on the dependence of different gun parameters and selection of optimal conditions are required to achieve high RF gun phase stability. The phase stability of the RF field is measured using the phase scan technique. Measurements were performed for different operating conditions at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). Obtained stability measurement results will be presented and discussed.

MOPC155	Performance of the Micro-TCA Digital Feedback Board for DRFS Test at KEK-STF	cavity, controls, klystron, LLRF	445
	T. Miura, D.A. Arakawa, S. Fukuda, E. Kako, H. Katagiri, T. Matsumoto, S. Michizono, Y. Yano KEK, Ibaraki, Japan
	The test of distributed RF scheme (DRFS) for ILC was carried out at the superconducting RF test facility in KEK (KEK-STF). The LLRF system and two klystron units were installed in the same tunnel as SRF cavities. The vector-sum control for two cavities was done by using the micro-TCA digital feedback board. This board was the same one developed for the compact-ERL at KEK, but the software was changed for pulse operation. The result of the performance will be reported.

MOPC156	Operation Test of Distributed RF System with Circulator-less Waveguide Distribution in S1-Global Project at STF/KEK	cavity, klystron, superconducting-cavity, linac	448
	T. Matsumoto, M. Akemoto, D.A. Arakawa, S. Fukuda, H. Honma, E. Kako, H. Katagiri, S. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida KEK, Ibaraki, Japan
	Distributed RF System (DRFS) is one candidate for a single main linac tunnel design of International International Linear Collider (ILC). In the DRFS, more than ten 800-kW klystrons having a modulating anode are operated by a common DC power and a modulation anode modulator. Each klystron feeds its power into two superconducting cavities and its waveguide distribution system is configured without circulators. This DRFS consists of four SC cavities, two klystrons and a modulator was demonstrated in S1-Global project. The results of circulator-less operation in the DRFS will be reported.

MOPC164	Upgrade of the ISIS Synchrotron Low Power RF System	cavity, controls, ion, synchrotron	466
	A. Seville, N.E. Farthing, I.S.K. Gardner, R.J. Mathieson, J.W.G. Thomason STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom D.B. Allen STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	The ISIS synchrotron at the Rutherford Appleton Laboratory in the UK now routinely uses a dual harmonic RF system to accelerate beam currents in excess of 230 uA to run two target stations simultaneously. In order to give more stable control of the phase of the RF voltage at each of the fundamental (1RF) and second harmonic (2RF) cavities, changes have been made to the low power RF (LPRF) control systems. In addition to this a new FPGA based master oscillator has been commissioned for the first time, and further changes using digital technologies to replace other components of the LPRF system are to be investigated. This paper reports on the LPRF hardware commissioning and reliability.

MOPC166	Low RF Control Feedback and IQ Vector Modulator Compensation Functions	controls, linac, gun, coupling	472
	M.G. Fedurin, R. Malone, V. Yakimenko BNL, Upton, Long Island, New York, USA
	IQ vector modulator is key element of the gun and linac RF control circuits at Accelerator Test Facility at Brookhaven National Laboratory. IQ modulator calibration procedure was developed to find proper compensation functions in the conversion algorithm to minimize phase-amplitude coupling and setting-reading errors: rms(A_set - A_read )= 0.03dB, rms(Phi_set - Phi_read) = 0.3 deg. Since stabilization of the RF phase and amplitude is become critical for many experiments the slow feedback was developed and applied as well to significantly compensate drifts in RF system.

MOPO001	Interaction Point Feedback Design and Integrated Simulations to Stabilize the CLIC Final Focus*	controls, simulation, quadrupole, ground-motion	475
	G. Balik, L. Brunetti, G. Deleglise, A. Jeremie, L. Pacquet IN2P3-LAPP, Annecy-le-Vieux, France A. Badel, B. Caron, R. Le Breton SYMME, Annecy-le-Vieux, France A. Latina, J. Pfingstner, D. Schulte, J. Snuverink CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) accelerator has strong precision requirements on offset position between the beams. The beam which is sensitive to ground motion needs to be stabilized to unprecedented requirements. Different Beam Based Feedback (BBF) algorithms such as Orbit Feedback (OFB) and Beam-Beam Offset Feedback (BBOF) have been designed. This paper focuses on the BBOF control which could be added to the CLIC baseline. It has been tested for different ground motion models in the presence of noises or disturbances and uses digital linear control with or without an adaptive loop. The simulations demonstrate that it is possible to achieve the required performances and quantify the maximum allowed noise level. This amount of admitted noises and disturbances is given in terms of an equivalent disturbance on the position of the magnet that controls the beam offset. Due to the limited sampling frequency of the process, the control loop is in a very small bandwidth. The study shows that these disturbances have to be lowered by other means in the higher frequency range.

MOPO002	Fast Orbit Correction for the ESRF Storage Ring	power-supply, storage-ring, diagnostics, controls	478
	E. Plouviez, F. Epaud, J.M. Koch, K.B. Scheidt ESRF, Grenoble, France
	Today, at the ESRF, the correction of the orbit position is performed with two independent systems: one to deal with the slow movements and one to correct the motion in a range of up to 200Hz but with a limited number of fast BPMs and steerers. This later will be removed and one unique system will cover the frequency range from DC to 200Hz using all the 224 BPMs and the 96 steerers. Indeed, thanks to the procurement of the Liberas Brilliance and installation of new AC power supplies, it is now possible to access all the Beam positions at a frequency of 10 kHz and to drive a small current in the steerers in a 400Hz bandwidth. The first tests of correction of the beam position have been performed and will be presented. This new orbit correction system is also a powerful diagnostics system: the measurement and survey of the Ring's lattice parameters is possible thanks to the high measurement rate of very high resolution position data. Results of this will also be presented.

MOPO003	A Broadband RF Stripline Kicker for Damping Transversal Multibunch Instabilities	kicker, impedance, single-bunch, damping	481
	M. Schedler, D. Heiliger, W. Hillert, A. Roth ELSA, Bonn, Germany
	When operating an RF feedback system, being able to reliably act upon every single bunch is a necessity. By employing a broadband RF stripline kicker, any bunch displacement can be corrected for. In a 500 MHz accelerator, the decay time of the electromagnetic field inside the kicker has to be less than 2 ns in order to avoid the following bunch to be affected. By designing the kicker as an RF coax device matched to the line impedance of the power cables, perturbing reflected signals are avoided. Additionally, the kicking strength and thus the shunt impedance should be maximized over the full spectrum from DC to 250 MHz. The kicker design has been optimized to meet the above requirements by relying on CST Microwave Studio simulations. Their results and first measurements are presented.

MOPO004	A Longitudinal Kicker Cavity for a Bunch-by-bunch Feedback System at ELSA	cavity, kicker, simulation, impedance	484
	N. Heurich, W. Hillert, A. Roth, R. Zimmermann ELSA, Bonn, Germany
	At the Electron Stretcher Facility ELSA of Bonn University, a longitudinal bunch-by-bunch feedback system is currently being installed in order to damp multibunch instabilities and to enable a future intensity upgrade of up to 200 mA. As a main component, a longitudinal kicker cavity was developed and manufactured. The kicker requires a bandwidth of 250~MHz taking into account the bunch spacing of 2 ns at ELSA. Existing designs used at other facilities were optimized in view of the considerably larger bunch lenght at ELSA. The choice of 1.125 GHz as a center frequency is a result of these considerations. With the resulting low quality factor, the design had to be optimized in order to maximize the shunt impedance. The longitudinal feedback is succesfully working with the prototype installed in the stretcher ring. The design and detailed simulations of the geometry are discussed and laboratory measurements are presented.

MOPO005	A Transverse Feedback System using Multiple Pickups for Noise Minimization	kicker, pick-up, synchrotron, betatron	487
	M. Alhumaidi, A.M. Zoubir TU Darmstadt, Darmstadt, Germany
	A new concept for using multiple pickups for estimating beam angle at the kicker is addressed. The estimated signal should be the driving feedback signal. The signals from the different pickups are delayed, such that they correspond to the same bunch. Consequently a weighted sum of the delayed signals is suggested as an estimator of the beam angle at the kicker. The weighting coefficients are calculated such that the estimator is unbiased, i.e. the output corresponds to the actual beam angle at the kicker for non-noisy pickup signals. Furthermore, the estimator must give the minimal noise power at the output among all linear unbiased estimators. Finally results for the heavy ions synchrotron SIS 18 at the GSI are shown.

MOPO006	DAΦNE Bunch-by-bunch Feedback Upgrade as SuperB Design Test	diagnostics, factory, controls, luminosity	490
	A. Drago INFN/LNF, Frascati (Roma), Italy D. Teytelman Dimtel, San Jose, USA
	DAΦNE, the PHI-factory located in Frascati, has always shown dynamic behavior strongly dependent on the bunch-by-bunch feedback, since its first runs in 1997. Over the years, to keep up with the evolving machine requirements, transverse and longitudinal systems have received multiple upgrades and updates. During fall 2010, all the six DAΦNE feedback systems have been upgraded to support the next run for KLOE as well as to test bunch-by-bunch feedback architectures intended for the future Italian SuperB factory. Both e+/e^- longitudinal feedback systems have been completely replaced with new hardware for increased reliability, better diagnostics and improved maintainability. In the effort to reduce residual dipole beam motion, determined by the front-end and quantization noise floor, vertical feedback systems now feature a 12-bit ADC, in place of the older 8-bit design. In the paper, we describe the hardware and software changes of this upgrade. Feedback performance analysis and beam dynamics data collected by the systems are presented.

MOPO007	Resonant Strip-line Type Longitudinal Kicker	kicker, simulation, impedance, wakefield	493
	T. Nakamura JASRI/SPring-8, Hyogo-ken, Japan
	The longitudinal feedback for the SPring-8 storage ring is under consideration as the device for suppression of the longitudinal instabilities driven by higher order modes of cavities, observed at test operation with 4 to 6 GeV low energy beam. As the beam energy and the ring circumference are rather high, and the length of the space for the longitudinal kickers is limited, high efficiency kicker per length is required in the our case. As a candidate of such kicker, we propose a resonant strip-line type longitudinal kicker with drive frequency of 13/4 of RF frequency. The shut impedance per length is higher than over-loaded cavities and the drive circuits can be simplified because of higher drive frequency. The design consideration, the result of the simulation and measurement of the prototype model, and the detail of the drive circuit will be reported in the presentation.

MOPO008	Design and Simulation of the Transverse Feedback Kicker for the HLSⅡ	kicker, impedance, simulation, vacuum	496
	W.B. Li, P. Lu, B.G. Sun, F.F. Wu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to suppress the coupled bunch instabilities in the HLSⅡ storage ring, a transverse feedback system is required. The vital component of the system is the kicker that is the feedback actuator. We design a stripline kicker for the HLSⅡ. The horizontal and vertical electrodes are combined in a structure on account of the space limit. In addition to the design issues, this paper focuses on the simulation results for the kicker using the computer codes. By the 2D code POSSION, we calculate and optimize the characteristic impedance of the stripline kicker to match the 50Ω external transmission lines so as to reduce the reflected power. The reflection coefficient and the shunt impedance in the working frequency range are obtained by the 3D code HFSS. The simulation results provide many important supports for the structure design.

MOPO010	Orbit Feedback System for the MAX IV 3 GeV Storage Ring	vacuum, power-supply, storage-ring, simulation	499
	M. Sjöström, J. Ahlbäck, M.A.G. Johansson, S.C. Leemann, R. Nilsson MAX-lab, Lund, Sweden
	The paper describes the current orbit correction system design for the 3 GeV storage ring at the MAX IV laboratory, a light source facility under construction in Lund, Sweden. The orbit stability requirements for the 3 GeV storage ring are tight at roughly 200 nm vertical position stability in the insertion device (ID) straight sections. To meet this the ring will be equipped with 200 beam position monitors (BPMs) and 380 dipole corrector magnets, 200 in the horizontal and 180 in the vertical plane. The feedback loop solution, one slow orbit feedback (SOFB) loop and one fast orbit feedback (FOFB) loop in fast acquisition mode at 10,000 samples/second, will be presented. The paper will also discuss the various boundary conditions specific to the MAX IV 3 GeV storage ring design, such as a Cu vacuum chamber, and the impact on the corrector design.

MOPO012	LHC Damper Beam Commissioning in 2010	damping, injection, kicker, ion	505
	W. Höfle, G. Kotzian, M. Schokker, D. Valuch CERN, Geneva, Switzerland
	The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics have become part of the standard operations procedure. The system proved important to limit emittance blow-up at injection and maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for proton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap cleaning and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.

MOPO013	Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment	pick-up, emittance, betatron, simulation	508
	W. Höfle, G. Arduini, R. De Maria, G. Kotzian, D. Valuch CERN, Geneva, Switzerland V.A. Lebedev Fermilab, Batavia, USA
	The LHC transverse dampers initially build to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noises at the frequencies of betatron sidebands. To prevent the emittance growth excited by magnet noise using the damper this system has to have extremely low noise properties. The paper discusses simulation results on the effectiveness of the transverse feedback system to suppress such oscillations and the experimental results from a damper point of view as they were gained during the 2010 LHC run. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.

MOPO014	SVD-based Filter Design for the Trajectory Feedback of CLIC	ground-motion, luminosity, controls, simulation	511
	J. Pfingstner, D. Schulte, J. Snuverink CERN, Geneva, Switzerland M. Hofbaur UMIT, Hall in Tirol, Austria
	The orbit feedback of the Compact Linear Collider (CLIC) is the basic counter-measure against ground motion effects below 1 Hz in the beam delivery system and the main linac of CLIC. In this paper we present significant improvements of the orbit feedback design, by using time-dependent and spatial filters. The design procedure is based on a singular value decomposition (SVD) of the orbit response matrix and on loop-shaping techniques. This modified design has essential advantages compared to previous ones. The required beam position monitor resolution in the beam delivery system could be relaxed by a factor of five. At the same time the suppression of ground motion effects is improved. As a consequence, the tight tolerances for the allowable luminosity loss due to ground motion effects in CLIC can be met. The presented methods can be easily adapted to other accelerators in order to relax sensor tolerances and to efficiently suppress ground motion effects.

MOPO015	Operation Status of Bunch-by-bunch Feedback System in the TLS	controls, injection, diagnostics, kicker	514
	C.H. Kuo, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao NSRRC, Hsinchu, Taiwan
	There are several FPGA based bunch-by-bunch feedback systems that were deployed in the Taiwan Light Source now. They play various roles to suppress beam instability. By using SPring-8 designed feedback processors is pioneer to apply in the storage ring of TLS successfully and help Dimtel system to be quick commission. The Dimtel feedback system provide a life spare unit and explore to control system integration especially to the EPICS toolkit system. Rich functionality includes of excitation of individual bunch or specifies bunches, averaged spectrum, tune measurement by the feedback dip in the averaged spectrum. Operation status of the system will be summary in this report.

MOPO016	Commissioning Tune Feedback in the Taiwan Light Source	insertion, insertion-device, controls, undulator	517
	C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The tune control is important parameter in the insertion devices operation. There are many difference type insertion devices are disturbed in the storage ring of TLS. The traditional feed-forward control to correct orbit change and tune shift that isn’t enough when difference type insertion devices are operated with various condition. The tune feedback is used to solve the tune change problem. The stable tune measurement is necessary in the stable storage ring. There are various excited bunch train methods to get stable tune that will be also discussed in this report.

MOPO017	Latest Performance Results from the FONT5 Intra-train Position and Angle Feedback System at ATF2	kicker, linear-collider, collider, positron	520
	G.B. Christian, D.R. Bett, M.R. Davis, C. Perry JAI, Oxford, United Kingdom R. Apsimon, P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Constance, A. Gerbershagen CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-to-bunch timescales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. An overview of the hardware, and the latest results from beam tests at ATF2, will be presented. A total system latency as low as approximately 140 ns has been demonstrated.

MOPO018	Active Beam Current Stabilization in the Cornell ERL Prototype Injector	laser, gun, cavity, cathode	523
	F. Löhl, P. Szypryt CLASSE, Ithaca, New York, USA
	In order to operate the Cornell ERL prototype injector at beam currents beyond 10 mA, the beam current has to be highly stable. The reason is that fast beam current fluctuations generate transient effects in the DC gun voltage as well as in the fields of subsequent superconducting cavities, which can lead to excessive beam loss or to trips of subsystems. Therefore, a feedback scheme was developed which uses the signal of a beam current monitor as an input, and applies appropriate corrections to a Pockels cell installed within the laser path of the photo-injector laser. In this paper, high current results achieved with this feedback scheme are presented.

MOPO022	Precision Beam Instrumentation and Feedback-Based Beam Control at RHIC	coupling, acceleration, controls, resonance	526
	M.G. Minty, W. Fischer, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, T. Roser, V. Schoefer, S. Tepikian, M. Wilinski BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this report we present advances in beam instrumentation required for feedback-based beam control at the Relativistic Heavy Ion Collider (RHIC). Improved resolution has contributed to enabling now routine acceleration with multiple feedback loops. Better measurement and control of the beam’s properties have allowed acceleration at a new working point and have facilitated challenging experimental studies.

MOPO026	Design, Manufacturing and Tests of Closed-loop Quadrupole Mover Prototypes for European XFEL	quadrupole, controls, alignment, vacuum	535
	J. Munilla, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, T. Martínez de Alvaro, E. Molina Marinas, S. Sanz, F. Toral, C. Vazquez CIEMAT, Madrid, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009 In this report the development of a quadrupole mover with submicron repeatability is reported, which will be used in the intersections of the Undulator Systems of the European XFEL (EXFEL). It is part of the Spanish in-kind contribution to this facility. The main specifications include submicron repeatability for a 70 kg quadrupole magnet within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear actuators based on 5-phase stepping motors have been chosen. Vertical actuator works in a wedge configuration to take mechanical advantage. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one LVDT sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. Prototyping stage is done and a serial production of more than 90 devices is expected, so intense work has been done to achieve a reliable industrial production and validation. In this report, results of mechanical measurements including reproducibility, tests of different operation strategies and critical situations will be reported.

MOPO027	Status of a Study of Stabilization and Fine Positioning of CLIC Quadrupoles to the Nanometre Level*	quadrupole, alignment, controls, damping	538
	K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, S.M. Janssens, A.M. Kuzmin, R. Leuxe, R. Moron Ballester CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no.227579 Mechanical stability to the nanometre and below is required for the CLIC quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterization of vibration sources was extended to forces acting directly on the magnet, such as water-cooling induced vibrations. This paper shows the achievements, improvements, and an outlook on further R&D.

MOPO029	Validation of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider using a Test Setup (Mock-up) with 5 Degrees of Freedom	quadrupole, alignment, target, controls	544
	H. Mainaud Durand, M. Anastasopoulos, J. Kemppinen, R. Leuxe, M. Sosin, S. griffet CERN, Geneva, Switzerland
	The CLIC main beam quadrupoles need to be pre-aligned within 17μm rms with respect to a straight reference line along a sliding window of 200 m. A re-adjustment system based on eccentric cam movers, which will provide stiffness to the support assembly, is being studied. The cam movers were qualified on a 1 degree of freedom (DOF) test setup, where a repeatability of adjustment below 1 μm was measured along their whole range. This paper presents the 5 DOF mock-up, built for the validation of the eccentric cam movers, as well as the first results of tests carried out: resolution of displacement along the whole range, measurements of the support eigenfrequencies.

MOPO039	B-train Performances at CNAO	dipole, synchrotron, power-supply, extraction	568
	M. Pezzetta, G. Bazzano, E. Bressi, L. Falbo, C. Priano, M. Pullia CNAO Foundation, Milan, Italy O. Coiro, G. Franzini, D. Pellegrini, M. Serio, A. Stella INFN/LNF, Frascati (Roma), Italy G. Venchi University of Pavia, Pavia, Italy
	The commissioning of CNAO, the Italian Centre of Oncological Hadrontherapy, with proton beams is completed. The real-time measurement of the synchrotron dipole field with the so-called B-train, together with its electronic systems and related software and firmware are here described. An additional magnet, powered in series with the synchrotron dipoles, is equipped with a special coil that measures the field integral variation along the beam nominal path. The voltage induced in the coil is digitized with a fast ADC and numerically integrated by an FPGA. The field integral is then distributed to the users every time that the equivalent field changes by 0.1 G. The measured B field ranges from 0 to 1.6 T with maximum ramps of 3 T/s. The B-train system will be used to provide feedback in field to the dipole power supply. It will handle the limited bandwidth of the active filter, the B-field lag in the magnets and will avoid current jumps.

MOPS049	Study of Ion-induced Instabilities and Transverse Feedback Performance at SOLEIL	ion, vacuum, simulation, electron	712
	R. Nagaoka, L. Cassinari, M.D. Diop, J.-M. Filhol, M.-P. Level, A. Loulergue, P. Marchand, R. Sreedharan SOLEIL, Gif-sur-Yvette, France
	Experimental studies indicate that the SOLEIL storage ring at its maximum designed current of 500 mA is under a large influence of ions, potentially capable of inducing the so called fast beam-ion instability. To avoid it, the following three conditions have been empirically found effective: A reduced RF voltage, uniform filling and a large vertical chromaticity. While the choice of uniform filling appears contradictory to raising the ion instability threshold, it goes well with lowering of the RF voltage if outgassing due to beam-induced heating of the vacuum components is the primary source of ions. Additional difficulties associated are frequent occurrence of sudden beam blowups despite the presence of transverse feedback, which are large enough to trigger machine interlocks leading to complete beam losses. These blow ups may even take place horizontally inside in-vacuum insertion devices. The present paper reports on the results and findings obtained through experimental and simulation studies carried out on the collective beam dynamics and the transverse feedback performance, which are deeply interlinked, in order to clarify the mechanism of the encountered phenomena.

MOPS084	Status of Electron Cloud Dynamics Measurements at CESRTA*	dipole, electron, betatron, damping	799
	M.G. Billing, G. Dugan, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, J.P. Sikora, K.G. Sonnad, H.A. Williams CLASSE, Ithaca, New York, USA J.Y. Chu CMU, Pittsburgh, Pennsylvania, USA J.W. Flanagan KEK, Ibaraki, Japan R. Holtzapple, M. Randazzo CalPoly, San Luis Obispo, California, USA
	Funding: Supported by US National Science Foundation (PHY-0734867) & Dept. of Energy (DE-FC02-08ER41538) The study of electron cloud-related instabilities for the CESR-TA project permits the observation of the interaction of the electron cloud with the stored beam under a variety of accelerator conditions. These measurements are undertaken utilizing automatic and semi-automatic techniques for three basic observations: the measurement of tune shifts of individual bunches along a train, the detection of the coherent self-excited spectrum for each bunch within a train and the pulsed excitation of either the betatron dipole or head-tail mode for each individual bunch within the train, followed by the observation of the damping of its coherent motion. These techniques are employed to study the electron cloud-related interactions in a number of conditions, such as trains of bunches with low emittance and spaced by as little as 4 nsec between bunches. We report on the most recent observations and results.

MOPS089	Identification of Bunch Dynamics in the Presence of E-cloud and TMCI for the CERN SPS Ring	simulation, controls, coupling, kicker	811
	O. Turgut, J.D. Fox, C.H. Rivetta, S. Uemura SLAC, Menlo Park, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work is supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). Measurements and multi-particle simulation codes (i.e. HEAD-TAIL, WARP, CMAD) indicate that bunched particle beams show unstable motions induced by electron-clouds and strong head-tail interactions. The bunch dynamics exhibits highly non-linear, complex and unstable behavior under certain operating conditions. Feedback control systems have been proposed to mitigate these instabilities in the CERN SPS ring. The design of feedback systems requires the knowledge of a reduced dynamic model of the bunch. It allows to include and quantify the effect of noise and signal perturbations, as well as system robustness to parameter variation. Identification techniques are used to estimate those models based on bunch motion measurements. In this work we present reduced mathematical models representing the transverse bunch dynamics and identification techniques to extract the model parameters based on measurements. These techniques are validated using time domain simulations of the bunch motion conducted using multi-particle simulation codes. For that, different sections of the bunch are driven by random signals, and the vertical motion of those areas is used to estimate the reduced model.

TUODA01	Vertical Emittance Reduction and Preservation at the ESRF Electron Storage Ring	emittance, coupling, quadrupole, storage-ring	928
	A. Franchi, J. Chavanne, F. Ewald, L. Farvacque, T.P. Perron, K.B. Scheidt ESRF, Grenoble, France
	In 2010 a campaign for the reduction and preservation of low vertical emittance at the ESRF electron storage ring was undertaken: values between 20 and 30 pm have been dramatically reduced to 3.5-4.5 pm, even during beam delivery. This improvement is the result of an increased measurement precision provided by the recently upgraded beam position monitoring system, a new correction algorithm, a larger number of correctors and two independent schemes for the automatic compensation of coupling induced by a few insertion devices whenever their gaps are moved by users during beam delivery. This paper summarizes the campaign's milestones and the results updated to the first half of 2011.
	Slides TUODA01 [5.297 MB]

TUPC014	System Control for the CLIC Main Beam Quadrupole Stabilization and Nano-positioning*	quadrupole, luminosity, ground-motion, simulation	1021
	S.M. Janssens, K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, A.M. Kuzmin, R. Leuxe, J. Pfingstner, D. Schulte, J. Snuverink CERN, Geneva, Switzerland
	The conceptual design of the active stabilization and nano-positioning of the CLIC main beam quadrupoles was validated in models and experimentally demonstrated on test benches. Although the mechanical vibrations were reduced to within the specification of 1.5 nm at 1 Hz, additional input for the stabilization system control was received from integrated luminosity simulations that included the measured stabilization transfer functions. Studies are ongoing to obtain a transfer function which is more compatible with beam based orbit feedback; it concerns the controller layout, new sensors and their combination. In addition, the gain margin must be increased in order to reach the requirements from a higher vibration background. For this purpose, the mechanical support is adapted to raise the frequency of some resonances in the system and the implementation of force sensors is considered. Furthermore, this will increase the speed of repositioning the magnets between beam pulses. This paper describes the improvements and their implementation from a controls perspective.

TUPC023	Status of Ground Motion Mitigation Techniques for CLIC	luminosity, quadrupole, simulation, ground-motion	1048
	J. Snuverink, K. Artoos, C.G.R.L. Collette, F. Duarte Ramos, A. Gaddi, H. Gerwig, S.M. Janssens, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland G. Balik, L. Brunetti, A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Caron SYMME, Annecy-le-Vieux, France J. Resta-López IFIC, Valencia, Spain
	The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques are proposed - quadrupole stabilisation and positioning, final doublet stabilisation as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of the ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) have been performed, which model the hardware and beam performance in detail. Based on the results future improvements of the mitigation techniques are suggested and simulated. It is shown that with the current design the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed.

TUPC027	CLIC Post-Collision Line Luminosity Monitoring	photon, luminosity, simulation, monitoring	1057
	R. Appleby UMAN, Manchester, United Kingdom A. Apyan, L.C. Deacon, E. Gschwendtner CERN, Geneva, Switzerland
	The CLIC post collision line is designed to transport the un-collided beams and the products of the collided beams with a total power of 14 MW to the main beam dump. Full Monte Carlo simulation has been done for the description of the Compact Linear Collider (CLIC) luminosity monitoring at the post collision line. One method of the luminosity diagnostic is based on the detection of high energy muons produced by the beamsstrahlung photons in the main beam dump. The disrupted beam and the beamsstrahlung photons produce at the order of 10⁶ muons per bunch crossing, with energies greater than 10 GeV. Currently threshold Cherenkov counters are considered after the beam dump for the detection of these high energy muons. A second method using the direct detection of the beamsstrahlung photons is also considered.

TUPC068	SOLEIL Beam Orbit Stability Improvements	booster, synchrotron, photon, power-supply	1156
	N. Hubert, Y.-M. Abiven, F. Blache, F. Briquez, L. Cassinari, J.-C. Denard, J.-F. Lamarre, P. Lebasque, N. Leclercq, A. Lestrade, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	The electron beam orbit stability has been significantly improved at synchrotron SOLEIL. Low frequency noise sources have been localized and identified: the fans installed on the storage ring to cool down the ceramic chambers of the kickers, shaker and FCT, were slightly wobbling the electron beam orbit at 46, 50, 54 and 10⁸ Hz. The localization method and the solutions that will allow reducing the noise from 0.8 μm RMS down to 0.3 μm are presented. Besides, a new 160 m long beamline, NANOSCOPIUM, is being installed on a canted straight section. Its photon beam position stability requirements are very tight calling for the following improvements: addition of 2 more BPMs and fast correctors in the orbit feedback loops, new INVAR stands for BPM and XBPM integrating Hydrostatic Level System sensors. The paper is also discussing other projects that did or will contribute to improving the beam orbit stability: installation of 145 temperature sensors on the storage ring, a new analog feedforward correction system for insertion devices, and the use of the bending magnet X-BPM measurements in the slow and fast orbit feedback loops.

TUPC089	New Digital NMR System for an Old Analyzing Magnet	controls, power-supply, cyclotron, resonance	1215
	Z. Kormány, I. Ander ATOMKI, Debrecen, Hungary
	The analyzing magnet of the ATOMKI cyclotron measures the beam energy with high precision and can lower its energy spread to ~5x10^-4. The highly stable magnetic field is achieved by a NMR-feedback in the control loop of the power supply. The original analog system was designed and built over 25 years ago applying mainly obsolete, partly nowadays unavailable components. Maintaining and keeping the system running required increasing efforts every year. A new digital system has been developed to replace the old one. Except the high-frequency signal domain (HF oscillator and preamplifier) it performs every processing digitally. Its heart is a mixed-signal microcontroller that generates the signals for the NMR-probe, measures the amplitude and frequency of the oscillation, evaluates the demodulated signal and controls the power supply. A fast NMR-pulse detection algorithm was developed; as a result the embedded program can perform all measuring, detecting and controlling tasks in real-time. A PC connects to the controller, sends commands and displays the received signals and status data. The control software allows easy handling of the complete system with nearly automated operation.

TUPC103	Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR	injection, kicker, betatron, quadrupole	1254
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan M. Takagi Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan M. Tejima, T. Toyama KEK, Ibaraki, Japan
	The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC107	Some Preliminary Experiments using LIBERA BPMs in BEPCII*	coupling, resonance, injection, kicker	1266
	Y. Zhang, H.Z. Ma, J. Yue IHEP Beijing, Beijing, People's Republic of China
	Funding: Supported by the National Natural Science Foundation of China (10805051) There are total 16 LIBERA BPMs in BEPCII, which is a double ring e⁺e⁻ collider. The turn-by-turn BPMs serve as only tune measurement system in most cases during normal operation. We tried to do some more machine study using them: the local coupling parameter at the BPM, the resonance driving term, the decoherence parameter which could be used to calibrate the strength of octupole in the ring. We also compare the difference from the different exciting method: single time kick with injection kicker or sinusoidal kick with feedback system.

TUPC112	Photon Beam Position Monitor based on Position-sensitive Detector for HLS*	photon, synchrotron, injection, diagnostics	1281
	Y.Y. Xiao, L.M. Gu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to overcome the limitation that the existing photon beam position monitors (PBPM) cannot measure the beam position in vertical and horizontal at the same time, a new photon beam position monitor based on position-sensitive detector (PSD) has developed at HLS (Hefei Light Source). The new PBPM based on the PSD has very fast response speed, high sensitivity and wide dynamic range. This PBPM system also includes the C4674 signal processing circuit, NI USB-9215 data acquisition device and the LABVIEW data acquisition program. This PBPM system has been calibrated vertically and horizontally on-line, then has been applied in the beam line B3EA of HLS to measure the position of the synchrotron light. Some results are given.

TUPC116	Beam Diagnostics Global Data Warehouse Implementation and Application at SSRF*	diagnostics, EPICS, controls, monitoring	1287
	Y.B. Leng, Z.C. Chen, Y.B. Yan, R.X. Yuan SSRF, Shanghai, People's Republic of China
	A fully functional beam diagnostics system has been developed at SSRF serving user operation and machine study since 2009. Global orbit disturbances, BPM failures and DCCT noise signal have been observed randomly. Without correct event trigger it is hard to capture real time data and analyze the cause of the above failures. A BI global data warehouse has been implemented as a solution to buffer online data and do correlation analyze at SSRF.

TUPC117	Embedded EPICS IOC Data Acquisition System for Beam Instability Research	betatron, wakefield, EPICS, storage-ring	1290
	N. Zhang, Y.B. Leng SSRF, Shanghai, People's Republic of China
	Funding: This research is supported by National Natural Science Fund(No.Y155131061). To be a part of beam diagnostics system in SSRF 3.5 GeV electron storage ring, a high performance oscilloscope is introduced to build a bunch by bunch data acquisition and processing dedicated system, which is mainly used to observe individual bunch position in transverse plane and bunch charge. By analysis of Betatron oscillation amplitude distribution and corresponding filling pattern, we hope to find phenomenon about multi-bunch Wakefield effect[1] on beam Betatron oscillation for beam instability research. The system is configured as a scope IOC, and integrated into the EPICS based control system. Application of this system and some data analysis results are also discussed in this paper.

TUPC118	Test Results on Beam Position Resolution for Low-Q IP-BPM at KEK-ATF2	cavity, alignment, collider, dipole	1293
	S.W. Jang, A. Heo, J.G. Hwang, E.-S. Kim, H.-S. Kim Kyungpook National University, Daegu, Republic of Korea H.K. Park CHEP, Daegu, Republic of Korea
	We have performed the beam tests on the beam position resolution for the Low-Q IP-BPM (Interaction Point-Beam Position Monitor) at ATF2 which is an accelerator test facility for the International Linear Collider. The main goals of KEK-ATF2 are to achieve beam size of 37 nm and beam resolution of nano-meter for beam stabilization. Resolution tests for the Low-Q IP-BPM were performed with KEK BPM doublet in Jan. 2011. We got the results of beam position resolution 70 nm during the experimental periods and will present the detailed experimental procedures and results.

TUPC128	Transverse Beam Jitter Propagation in Multi-bunch Operation at ATF2	extraction, simulation, kicker, lattice	1320
	J. Resta-López, J. Alabau-Gonzalvo IFIC, Valencia, Spain P. Burrows, G.B. Christian JAI, Oxford, United Kingdom B. Constance CERN, Geneva, Switzerland
	Pulse-to-pulse orbit jitter, if not controlled, can drastically degrade the luminosity in future linear colliders. The second goal of the ATF2 project at the KEK accelerator test facility is to stabilize the vertical beam position down to approximately 5% of the nominal rms vertical beam size at the virtual interaction point (IP). This will require control of the orbit to better than 1 micrometer at the entrance of the ATF2 final focus system. In this paper, by means of computer simulations, we study the vertical jitter propagation along the ATF2 from the start of the extraction line to the IP. For this study pulse-to-pulse vertical jitter measurements using three stripline beam position monitors are used as initial inputs. This study is performed for the case of a bunch-train with three bunches, but could easily be extended for a larger number of bunches. The cases with and without intra-train orbit feedback correction in the extraction line of ATF2 are compared.

TUPC144	Preliminary BPM Electrics Testing for the Taiwan Photon Source Project	injection, brilliance, controls, electron	1362
	C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao NSRRC, Hsinchu, Taiwan
	The preliminary BPM electrics are developing and testing for Taiwan Photon Source (TPS), is a 3 GeV synchrotron light source which being in construction at NSRRC. This new BPM electronics with integrated FPGA based hardware, and will be testing in the TLS (Taiwan Light Source) with real beam at first. The enhance functionality of current generation will be adopted in the TPS. The electronic prototype testing and relative property will be reported in this report.

TUPC157	Design and Initial Results of a Turn-by-Turn Beam Position Monitoring System for Multiple Bunch Operation of the ATF Damping Ring	injection, damping, single-bunch, extraction	1398
	G.B. Christian, D.R. Bett, M.R. Davis, C. Perry JAI, Oxford, United Kingdom R. Apsimon, P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Constance, A. Gerbershagen CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	An FPGA-based monitoring system has been developed to study multi-bunch beam instabilities in the damping ring (DR) of the KEK Accelerator Test Facility (ATF), utilising a stripline beam position monitor (BPM) and existing BPM processor hardware. The system is designed to record the horizontal and/or vertical positions of up to three bunches in the DR in single-bunch multi-train mode or the head bunch of up to three trains in multi-bunch mode, with a bunch spacing of 5.6 ns. The FPGA firmware and data acquisition software were modified to record turn-by-turn data for up to six channels and 1–3 bunches in the DR. An overview of the system and initial results will be presented.

TUPC159	Energy Measurements with Resonant Spin Depolarisation at Diamond	electron, storage-ring, resonance, quadrupole	1404
	I.P.S. Martin, M. Apollonio, R.T. Fielder, G. Rehm Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	A precise knowledge of the electron beam energy is critical for the accurate determination of many light source parameters, such as momentum compaction factor, natural chromaticity, energy stability and undulator spectra. In common with other facilities, a method of energy measurement based on resonant spin depolarisation has been developed at Diamond. In this paper we report on progress towards storage ring characterisation using this method, as well as describing the diagnostics developments that have enabled these measurements to be made.

TUPC160	Recent Developments of Diagnostics at Diamond	photon, synchrotron, undulator, diagnostics	1407
	G. Rehm, C. Bloomer, A.F.D. Morgan, C.A. Thomas Diamond, Oxfordshire, United Kingdom
	This contribution summarizes some recent development of diagnostics system to improve the operation of Diamond Light Source. Firstly, we are advancing the integration of photon beam diagnostics with the orbit feedback system. Measurements have shown the correlation between recorded electron and photon beam motion on the short timescales (ms-minutes) and the potential for improvement on long timescales (minutes-days). Secondly, with the addition of more elliptically polarized undulators at Diamond, measurement of their photon beam position require a solution that reliably operates with the changing photon beam profiles emitted by these devices. To this end, we have developed an X-ray beam position monitor that analyzes the backscatter from an aperture in the front end. Thirdly, as operation in low-alpha mode with few ps bunch lengths receives increasing interest from users, we have been evaluating various techniques for the measurement of these short bunch lengths that could serve as alternatives to streak camera measurements.

TUPS040	Driving the LHC Collimators' Stepping Motors over 1 km with High Accuracy avoiding EMI Effects	controls, impedance, beam-losses, radiation	1626
	A. Masi, G. Conte, R. Losito, M. Martino CERN, Geneva, Switzerland
	The LHC collimators are exposed to very high levels of radiation, which means that the power drivers must be installed far from the stepping motors that they drive. Due to the geometry of the underground installations, the distances can be up to 1 km. The long cables that connect the drivers to the motors behave as transmission lines modifying dramatically the impedance seen by the drivers and consequently jeopardizing the control performance of Pulse Width Modulation (PWM) drivers. In this paper we address this problem, provide an analytical model of the driver-cable-motor system and describe the analog solution we have developed to improve the performance of a typical off the shelf driver. Finally we characterize the improvement of the performances with measurements of positioning repeatability and show that electromagnetic emissions from the long cables are drastically reduced, making the use of stepping motors compatible with extremely sensitive instrumentation such as the LHC Beam Loss Monitors (BLM).

TUPS059	SPS WANF Dismantling: A Large Scale-Decommissioning Project at CERN	radiation, shielding, target, ion	1668
	S. Evrard, Y. Algoet, N. Conan, D. DePaoli, I. Efthymiopoulos, S. Fumey, H. Gaillard, J.L. Grenard, D. Grenier, A. Pardons, E. Paulat, Y.D.R. Seraphin, M. Tavlet, C. Theis, H. Vincke CERN, Geneva, Switzerland
	The operation of the SPS (Super Proton Synchrotron) West Area Neutrino Facility (WANF) was halted in 1998. In 2010 a large scale-decommissioning of this facility was conducted. Besides CERN’s commitment to remove non-operational facilities, the additional motivation was the use of the installation (underground tunnels and available infrastructure) for the new HiRadMat facility, which is designed to study the impact of high-intensity pulsed beams on accelerator components and materials. The removal of 800 tons of radioactive equipment and the waste management according to the ALARA (As Low As Reasonably Achievable) principles were two major challenges. This paper describes the solutions implemented and the lessons learnt confirming that the decommissioning phase of a particle accelerator must be carefully studied as from the design stage.

TUPZ010	Longitudinal Emittance Blow-up in the LHC	emittance, synchrotron, damping, acceleration	1819
	P. Baudrenghien, A.C. Butterworth, M. Jaussi, T. Mastoridis, G. Papotti, E.N. Shaposhnikova, J. Tückmantel CERN, Geneva, Switzerland
	The LHC relies on Landau damping for longitudinal stability. To avoid decreasing the stability margin at high energy, the longitudinal emittance must be continuously increased during the acceleration ramp. Longitudinal blow-up provides the required emittance growth. The method was implemented through the summer of 2010. We inject band-limited RF phase-noise in the main accelerating cavities during the whole ramp of about 11 minutes. Synchrotron frequencies change along the energy ramp, but the digitally created noise tracks the frequency change. The position of the noise-band, relative to the nominal synchrotron frequency, and the bandwidth of the spectrum are set by pre-defined constants, making the diffusion stop at the edges of the demanded distribution. The noise amplitude is controlled by feedback using the measurement of the average bunch length. This algorithm reproducibly achieves the programmed bunch length of about 1.2 ns (4 σ) at flat top with low bunch-to-bunch scatter and provides a stable beam for physics coast.

TUPZ028	Beam Based Optimization of the Squeeze at the LHC	optics, beam-losses, simulation, controls	1867
	X. Buffat EPFL, Lausanne, Switzerland M. Lamont, S. Redaelli, J. Wenninger CERN, Geneva, Switzerland
	The betatron squeeze is a critical operational phase for the LHC because it is carried out at top energy, with the maximum stored energy and with reduced aperture margins in the superconducting triplets. A stable operation with minimum beam losses must be achieved in order to ensure a safe and efficient operation. The operational experience at the LHC showed that this is possible. The operation in 2010 is reviewed. In particular, orbit, tune and chromaticity measurements are investigated and correlated to beam losses. Different optimizations are then proposed towards a more efficient and robust operation. The improvements obtained for the operation in 2011 are presented.

TUPZ035	RHIC Polarized Proton Status and Operation Highlights	polarization, resonance, emittance, controls	1888
	H. Huang, L. A. Ahrens, I.G. Alekseev, E.C. Aschenauer, G. Atoian, M. Bai, A. Bazilevsky, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, A. Dion, K.A. Drees, W. Fischer, J.W. Glenn, X. Gu, L.T. Hoff, C. Liu, Y. Luo, W.W. MacKay, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, M.G. Minty, C. Montag, J. Morris, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, D. Smirnov, S. Tepikian, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, S.Y. Zhang BNL, Upton, Long Island, New York, USA D. Svirida ITEP, Moscow, Russia
	RHIC operation as the polarized proton collider presents unique challenges since both luminosity and spin polarization are important. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system has been installed to improve longitudinal match at injection and to increase luminosity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control has also been improved this year. AGS polarization transfer efficiency is improved by a horizontal tune jump system. To preserve polarization on the ramp, a new working point was chosen with the vertical tune near a third order resonance. The orbit and tune control are essential for polarization preservation. To calibrate the polarization level at 250 GeV, polarized protons were accelerated up to 250GeV and decelerated back to 100GeV. The tune, orbit and chromaticity feedback is essential for this operation. The new record of luminosity was achieved with higher polarization at 250 GeV in this run. The overview of the changes and operation results are presented in this paper.

TUPZ038	RHIC Performance for FY2011 Au+Au Heavy Ion Run	luminosity, cavity, ion, heavy-ion	1894
	G.J. Marr, L. A. Ahrens, M. Bai, J. Beebe-Wang, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, C. Carlson, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, W. Fu, C.J. Gardner, D.M. Gassner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, M. Lafky, J.S. Laster, C. Liu, Y. Luo, M. Mapes, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, S. Polizzo, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, C. Schultheiss, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, B. Van Kuik, G. Wang, M. Wilinski, A. Zaltsman, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Following the Fiscal Year (FY) 2010 (Run-10) Relativistic Heavy Ion Collider (RHIC) Au+Au run [1], RHIC experiment upgrades sought to improve detector capabilities. In turn, accelerator improvements were made to improve the luminosity available to the experiments for this run (Run-11). These improvements included: a redesign of the stochastic cooling systems for improved reliability; a relocation of “common” RF cavities to alleviate intensity limits due to beam loading; and an improved usage of feedback systems to control orbit, tune and coupling during energy ramps as well as while colliding at top energy. We present an overview of changes to the Collider and review the performance of the collider with respect to instantaneous and integrated luminosity goals.

WEOAA01	The ThomX Project	laser, injection, cavity, synchrotron	1903
	A. Variola LAL, Orsay, France
	Funding: Work supported by the EQUIPEX program, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI ThomX is a Compton source project in the range of the hard X rays (40 / 90 keV). The machine is composed of an injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a Fabry-Perot resonator. The final goal is to provide an X-rays average flux of 1011/10¹³ ph/s. The emitted flux will be characterized by a dedicated X-ray line. Different users are partners in the ThomX project, especially in the area of medical science and cultural heritage. Their main goal will be the transfer of all the experimental techniques developed on big synchrotron rings to these more compact and flexible machines. The project ThomX has recently been funded and will be located on the Orsay University campus. In this article the project and its associated scientific interest are presented.
	Slides WEOAA01 [5.947 MB]

WEIB02	Towards Developing Accelerators in Half the Time	controls, alignment, target, background	1978
	D.G. Reinertsen Reinertsen & Associates, Redondo Beach, California, USA
	The talk challenges conventional wisdom about how to improve product development processes and broadens the concept of product development cycle time reduction techniques. It provides some original ideas; it discusses approaches to managing product architecture that are well suited for rapid development and how the engineering concepts of system architecture, queuing theory, feedback theory, and information theory can be applied to manage the product development management.
	Slides WEIB02 [0.159 MB]

WEPC049	Operation and Storage Ring Calibration with the Transverse Bunch-by-Bunch Feedback System at the Australian Synchrotron	sextupole, damping, synchrotron, storage-ring	2121
	M.J. Boland, Y.E. Tan ASCo, Clayton, Victoria, Australia D.J. Peake, R.P. Rassool, K.P. Wootton The University of Melbourne, Melbourne, Australia
	The first operational experience with the transverse bunch-by-bunch feedback system for the storage ring shows a doubling of the lifetime and the ability to damp instabilities caused by IVU gap changes. The system was also used to calibrate the ring by doing simultaneous measurements on several single bunches with different bunch currents. Using the bunch-by-bunch system's capability to excite the beam to large amplitudes, the non-linear beam dynamics were also measured and compared with the model.

WEPC091	Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System	extraction, quadrupole, controls, synchrotron	2220
	M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker GSI, Darmstadt, Germany
	Several issues concerning the envisaged SIS100 resonant extraction at GSI can be resolved with a simulation-lead approach for which a particle tracking code was developed. Applications to date have included: design and testing of data supply algorithms for the accelerator control system; requirements analysis for the power converter ripple in the quadrupoles forming the doublet focusing; and verification of the RF Knock-Out exciter's performance.

WEPC120	Status of JMAD, the JAVA-API for MADX	optics, controls, status, lattice	2292
	K. Fuchsberger, X. Buffat, Y.I. Levinsen, G.J. Müller CERN, Geneva, Switzerland
	MADX (Methodical Accelerator Design) is the de-facto standard software for modeling accelerator lattices at CERN. This feature-rich software package is implemented and still maintained in the programming languages C and FORTRAN. Nevertheless the controls environment of modern accelerators at CERN, e.g., of the LHC, is dominated by JAVA applications. A lot of these applications, for example, for lattice measurement and fitting, require a close interaction with the numerical models, which are all defined by the use of the proprietary MADX scripting language. To close this gap an API to MADX for the JAVA programming language (JMAD) was developed. JMAD was first presented to the public about one year ago. In the meantime, a number of improvements were done, and additional MADX features (e.g., tracking) were made available for JAVA applications. Additionally, the graphical user interface was improved, and the first release as open source software is in reach. This paper describes the current status and some new features of the project, as well as some usage examples.

WEPO036	Design of a Cryogenic Regulation Valve Box for SRF Operation at TPS	SRF, cryogenics, cavity, coupling	2475
	M.H. Chang, L.-H. Chang, L.J. Chen, F.-T. Chung, F. Z. Hsiao, M.-C. Lin, Y.-H. Lin, C.H. Lo, H.H. Tsai, Ch. Wang, T.-T. Yang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan L.L. Han, M.H. Tsai NTUT, Taiwan
	A 3-GeV light source named Taiwan Photon Source (TPS) at National Synchrotron Radiation Research Center (NSRRC) is under construction, and is scheduled for commissioning in 2013/2014. An SRF module of KEKB type has been selected for the TPS as the accelerating cavity of its storage ring. The SRF valve boxes, as part of the cryogenic transfer system, stabilize the cryogenic operational conditions required for various needs of SRF operation. The SRF operation requires a large dynamic variation in the cryogenic loading that challenges appropriate sizing of the cryogenic regulation valves to minimize the pressure drop and concurrently to maintain a fine regulation of pressure. Here, we report our design considerations for an SRF valve box with emphasis on highly stabilizing the helium pressure for SRF operation with a dual-return valve scheme. The estimated fluctuations of pressure due to finite accuracy of the valve opening decrease to a tenth of what is obtained from the conventional single return-valve scheme.

WEPZ007	Multi-mode, Two-beam Accelerator with Feedback	cavity, impedance, accelerating-gradient, RF-structure	2778
	S.V. Kuzikov, M.E. Plotkin IAP/RAS, Nizhny Novgorod, Russia
	A high-gradient accelerator consisted of the test and the drive beam structures is reported. The accelerating structure can be based on dielectric or corrugated cavities separated each other by irises. Each cavity is operated by several axisymmetric, TM-like eigen-modes with longitudinal indices to be related to frequencies. These modes are excited at Fourier harmonics of the drive current which consists of bunches spaced with the same period as test bunches. The superposition of the excited modes introduces a short RF pulse propagated in-phase with a moving test bunch and after reflection by iris (a feedback) this pulse can accelerate next bunch. Such longitudinally-sweeping RF field promises a reduction of the exposure time and due to compact space shape can help to obtain high shunt impedance.

THXA01	Recent Trends in Accelerator Control Systems	controls, EPICS, LLRF, coupling	2844
	I. Verstovšek, F. Amand, M. Pleško, K. Žagar Cosylab, Ljubljana, Slovenia
	The talk will discuss the approaches of different accelerators, such as FAIR, ESS, MedAustron, XFEL, etc. An overview of different approaches will be given with an emphasis of the recent spectrum of various realizations of accelerator control systems. The talk will not be limited to open source and off-the-shelf software frameworks only but will touch all trends in modern accelerators, including recent trends in hardware. The role of the control system will be highlighted as a common integration framework for various applications, with an emphasis on its increased complexity and scale, and the need for improved reliability and an appropriate service. How control systems can help support the requirements-shaping process early in the project will also be discussed.
	Slides THXA01 [1.535 MB]

THOAA02	Implementation of an Intensity Feedback-loop for an Ion-therapy Synchrotron	controls, extraction, ion, synchrotron	2851
	C. Schömers, E. Feldmeier, Th. Haberer, J. Naumann, R.E. Panse, A. Peters HIT, Heidelberg, Germany
	The Heidelberg Ion Therapy-Centre (HIT) started treatment of tumour patients in 2009. Its main acceleration stage is a synchrotron, where particles are extracted slowly, in the time frame of some seconds, to support the raster-scanning method. The slow extraction is driven by the transverse "RF-nockout-exciter". So far, this device has a variable but predefined amplitude curve. As the phase-space distribution of particles is not homogeneous and varies slightly from pulse to pulse, intensity-fluctuations of the extracted beam appear. Moreover, changing accelerator-settings requires a time-consuming re-adjustment of the exciter to achieve adequate beam-properties again. To keep the intensity on a predefined level, a feedback loop will be implemented. The actual-value of the intensity is provided by an ionization chamber in front of the patient. The feedback loop controls the amplitude of the Exciter, to adapt the number of extracted particles. Beside a rectangular spill with constant intensity, a dynamic intensity-adaptation during one spill with respect to the particular treatment-plan will be investigated. First tests for flat spill and variable intensity showed promising results.
	Slides THOAA02 [2.284 MB]

THPC010	Recent Developments at the Metrology Light Source	quadrupole, injection, synchrotron, vacuum	2927
	J. Feikes, T. Birke, O. Dressler, D.B. Engel, F. Falkenstern, B. Franksen, A. Heugel, H.-G. Hoberg, F. Hoffmann, J. Kuszynski, J. Rahn, M. Ries, P.O. Schmid, T. Schneegans, D. Schüler, G. Wüstefeld HZB, Berlin, Germany K.B. Bürkmann-Gehrlein, V. Dürr, H.G. Glass, G. Schindhelm BESSY GmbH, Berlin, Germany R. Klein PTB, Berlin, Germany
	The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, owns the electron storage ring Metrology Light Source (MLS) which was built and is operated by the Helmholtz-Zentrum Berlin [1, 2]. The MLS has been in regular user operation since April 2008 and supports synchrotron-radiation-based metrology and technological developments in the IR, UV, VUV and EUV spectral range. Here we report on recent progress to develop the MLS into a reliable, flexible and stable user facility.

THPC044	Operation and Performance Upgrade of the Soleil Storage Ring	undulator, vacuum, storage-ring, photon	3002
	A. Nadji, P. Brunelle, M.-E. Couprie, J.-C. Denard, J.-M. Filhol, J.-F. Lamarre, P. Lebasque, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	SOLEIL delivers photons to 24 beamlines. Up to 22 very diverse insertion devices (IDs) are now installed on the storage ring, and 4 more will come by summer 2011, including a Cryogenic undulator and an electromagnetic/permanent magnet helical undulator, both designed and built at SOLEIL. Work is continuing on beam dynamics and magnetic corrections to reduce the nonlinear effects of all these IDs. A new optics incorporating an additional quadrupole triplet in one long straight section has been successfully tested and will be put in operation by fall 2011. A new coupling correction will also be implemented to maintain the ratio of the vertical to the horizontal emittances at 1% for any IDs configuration. The electron beam orbit stability has been significantly improved reaching a residual noise of 300 nm RMS. Photon LIBERA modules of X-BPM located on the bends, will be integrated soon in the orbit feedback loops. 4905 hours have been delivered in 2010 to the beamlines with an availability of 96.3%. The user operation with the maximum current of 500 mA is foreseen to start by fall 2011, after the completion of the radiation safety tests of the beamlines.

THPC056	Orbit Studies during ALBA Commissioning	coupling, alignment, quadrupole, brilliance	3020
	M. Muñoz, G. Benedetti, D. Einfeld, Z. Martí CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The 3rd generation light source ALBA is in the commissioning stage. This paper review the results of the commissioning concerning the transversal beam behavior, in particular the orbit correction system, results from the beam based alignment (BBA), and coupling. The orbit control system of ALBA consists of 88 horizontal and vertical correctors, mounted as extra coils in the sextupole magnets, up to 10⁴ LIBERA BPMs (brilliance version). The correctors magnets would be used for both static orbit correction and for the fast orbit feedback mode, providing up to 1 mrad of correction in the static case. In phase one of the commissioning, the orbit has been corrected down to values of 50 um rms, with an estimated emittance ratio in the order of 1% .

THPO011	Practical Experience with Self-optimizing, High Dynamic Control of Accelerator Magnet Power Supplies	controls, power-supply, proton, resonance	3355
	H. Jäckle PSI, Villigen, Switzerland F. Jenni, X.H. Ke FHNW, Windisch, Switzerland
	In 1999, the first fully digitally controlled magnet power supplies were commissioned at PSI (Paul Scherrer Institute, Switzerland). Today, approximately 1000 of them are in use at PSI and a multiple of that worldwide. An extended PI structure is used for control. PI control is very effective and simple to use but the attainable dynamic performance is usually limited by the higher order characteristics of the output filter and the load. For the future we expect increasing requirements from highly dynamic applications, such as beam orbit feedback systems and fast scanning magnets for proton irradiation of tumors. Therefore, a self-optimizing power supply control system was developed in collaboration with the University of Applied Sciences Northwestern Switzerland. It is based on the second generation of PSI digital power electronics controller, which allows more complex control algorithms and higher sampling rates. This paper presents the achieved dynamic performance of the new control structure for various types of power supplies and magnets and compares them with the dynamic performance obtained using standard PI control.

THPO014	Analysis and Compensator Design of Magnet Correction Power Supply	controls, power-supply, simulation	3364
	Y.S. Wong, J.C. Huang, K.-B. Liu NSRRC, Hsinchu, Taiwan
	This paper presents a new method for the analysis and design of compensators for magnet correction (MC) power supply. The system has to need controllers to satisfy required gain and phase margin specifications and compensator by adding to circuit controller and switch. The gain-phase margin tester method can transform of the controller and find solutions on the figure. According to circuit frequency response and transfer function by theory analysis and simulation design new method compensators to improved anti-disturbance and stability of the system.

THPO017	Improvement of Output Current Characteristics for Bira MCOR30 Correction Magnet Power Supply	controls, power-supply, HOM, storage-ring	3373
	J.C. Huang, K.-B. Liu, Y.S. Wong NSRRC, Hsinchu, Taiwan
	The correction magnet power supplies installed at the Taiwan light source (TLS) are Bira Systems’ MCRO 30 power modules, a full-bridge configuration power stage converting the unregulated DC bulk power into a bi-polar current source. The MCOR 30 is theoretically regulated under a very fine control method, with this control method the Bira MCOR 30 should overcome the zero crossover distortion of a standard H-Bridge PWM schemes is used and result in a low frequency noise signature on the output when the magnet current is close to zero. The PWM control circuitry embedded in MCOR 30 theoretically but not really fulfills the purpose what the MCOR 30 want to achieve. With a home-made PWM control circuitry installed into MCOR 30, the width of real pulses can smoothly drop to zero, the MCOR 30 could output current not only with a low frequency noise signature but also much with higher bandwidth of frequency response and much lower Total Harmonic Distortion no matter what output current is demanded.

THPO018	N+1 Redundancy Power Supply System by Paralleling Current Converter Modules with Digital Regulation Control	controls, power-supply, simulation, storage-ring	3376
	B.S. Wang, K.-B. Liu, Y.S. Wong NSRRC, Hsinchu, Taiwan
	The N+1 redundancy power supply system is fulfilled with adopting the Bira System MCOR30s as a platform, eight pieces of Bira MCOR 30 power converter boards are installed at crate 2512 and outputs are connected together, the output current of these paralleled eight Bira MCOR 30 power converters are regulated by an external homemade digital control circuit. With homemade digital control circuit, these paralleled eight Bira MCOR 30 power converter modules could deliver up to 240A/30V with ±20ppm precision and stability. The digital regulation control circuit of the N+1 redundancy power supply system is implemented by using a multi-channel DAC5868 16-bits digital-to-analog converter (DAC)、a high speed AD8382 18-bits analog-to-digital converter and a TMS320F28335 digital signal processor (DSP). The update reference voltage frequency of DAC is 83.3 kHz. A DCCT is used as the current feedback component and the output current ripple of the N+1 redundancy power supply system is lower than 20ppm which is beyond the requirement of current TLS quadruple and sextuple power supplies and qualified to be used in the future TPS facility.

THPO019	TPS Fast Corrector Magnet Power Converter	power-supply, booster, controls, monitoring	3379
	Y.D. Li, K.-B. Liu NSRRC, Hsinchu, Taiwan
	With the increasing demand of the current output accuracy on the TPS(Taiwan Photon Source) project, the MCOR 30 correction power supplies used in current TLS ring are no longer sufficient to meet the TPS requirement. Therefore, power supply group developments a high-precision low output current power supply with a DCCT as an output current feedback component for correction magnets of the future TPS ring. During the research and development experiment phase, we found the DCCT is more possible damaged than the other components. With keeping the architecture of the high-precision low output current power supply, but the DCCT output current feedback component is replaced with a current sensing Shunt resistor. This paper will discuss the design methods of utilizing several different types current sensing Shunt resistor to reduce the cost of power supply and the probability of damage, and improve frequency response of power supply.

THPO020	TPS Digital Corrector Magnet Power Converter based on FPGA	controls, dipole, booster, quadrupole	3382
	Y.D. Li, Y.-C. Chien, K.-B. Liu NSRRC, Hsinchu, Taiwan
	This thesis presents the design and implementation of a FPGA-based fully digital-controlled programmable power supply.

THPS071	The HIMAC Beam-intensity Control System for Heavy-ion Scanning	controls, extraction, status, ion	3592
	K. Mizushima Chiba University, Graduate School of Science and Technology, Chiba, Japan T. Furukawa, Y. Iwata, K. Katagiri, K. Noda, S. Sato, T. Shirai NIRS, Chiba-shi, Japan E. Takeshita Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
	Raster scanning irradiation has been carried out at a HIMAC new treatment facility in NIRS. In order to reduce the difference between prescribed and delivered dose distribution, the accurate beam-intensity control with a low ripple and the fast beam-on/off switching are strongly required. For this purpose, we have developed a new beam-intensity control system using the RF-knockout slow extraction. To keep the beam rate constant, this system controls the transverse RF voltage with the feedback proportional-integral control. In addition, the beam-on/off response was improved by the fast quadrupole magnets and the implementation of the transverse beam preheating method. As a result of the system commissioning, it was verified that this system can modulate the beam-intensity with a low ripple and switch the beam-on/off with quick responses. We will report the result in detail.

THPZ003	The SuperB Project: Accelerator Status and R&D	luminosity, quadrupole, emittance, injection	3684
	M.E. Biagini, S. Bini, R. Boni, M. Boscolo, B. Buonomo, T. Demma, E. Di Pasquale, A. Drago, L.G. Foggetta, S. Guiducci, S.M. Liuzzo, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, U. Rotundo, C. Sanelli, M. Serio, A. Stecchi, A. Stella, S. Tomassini, M. Zobov INFN/LNF, Frascati (Roma), Italy M.A. Baylac, O. Bourrion, J.-M. De Conto, N. Monseu, C. Vescovi LPSC, Grenoble, France K.J. Bertsche, A. Brachmann, Y. Cai, A. Chao, M.H. Donald, R.C. Field, A.S. Fisher, D. Kharakh, A. Krasnykh, K.C. Moffeit, Y. Nosochkov, A. Novokhatski, M.T.F. Pivi, J.T. Seeman, M.K. Sullivan, S.P. Weathersby, A.W. Weidemann, U. Wienands, W. Wittmer, G. Yocky SLAC, Menlo Park, California, USA S. Bettoni PSI, Villigen, Switzerland A.V. Bogomyagkov, I. Koop, E.B. Levichev, S.A. Nikitin, I.N. Okunev, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin, P. Vobly BINP SB RAS, Novosibirsk, Russia B. Bolzon, M. Esposito CERN, Geneva, Switzerland F. Bosi INFN-Pisa, Pisa, Italy L. Brunetti, A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France A. Chancé CEA, Gif-sur-Yvette, France P. Fabbricatore, S. Farinon, R. Musenich INFN Genova, Genova, Italy E. Paoloni University of Pisa and INFN, Pisa, Italy C. Rimbault, A. Variola LAL, Orsay, France Y. Zhang IHEP Beijing, Beijing, People's Republic of China
	The SuperB collider project has been recently approved by the Italian Government as part of the National Research Plan. SuperB is a high luminosity (10³6 cm^-2 s^-1) asymmetric e⁺e⁻ collider at the Y(4S) energy. The design is based on a “large Piwinski angle and Crab Waist” scheme already successfully tested at the DAΦNE Phi-Factory in Frascati, Italy. The project combines the challenges of high luminosity colliders and state-of-the-art synchrotron light sources, with two beams (e⁺ at 6.7 and e^- at 4.2 GeV) with extremely low emittances and small beam sizes at the Interaction Point. As unique features, the electron beam will be longitudinally polarized at the IP and the rings will be able to ramp down to collide at the tau/charm energy threshold with one tenth the luminosity. The relatively low beam currents (about 2 A) will allow for low running (power) costs compared to similar machines. The insertion of beam lines for synchrotron radiation users is the latest feature included in the design. The lattice has been recently modified to accommodate insertion devices for X-rays production. A status of the project and a description of R&D in progress will be presented.

THPZ034	Semi-automatic Beam-based Alignment Algorithm for the LHC Collimation System	alignment, controls, collimation, beam-losses	3768
	G. Valentino, R.W. Assmann, S. Redaelli, N.J. Sammut, D. Wollmann CERN, Geneva, Switzerland G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	Full beam-based alignment of the LHC collimation system was a lengthy procedure as the collimators were set up manually. A yearly alignment campaign has been sufficient for now, although in future this may lead to a decrease in the cleaning efficiency if machine parameters such as the beam orbit drift over time. Automating the collimator setup procedure can allow for more frequent alignments, therefore reducing this risk. This paper describes the design and testing of a semi-automatic algorithm as a first step towards a fully automatic setup. Its implementation in the collimator control software and future plans are described.

FRXCA01	First Years Experience of LHC Beam Instrumentation	emittance, beam-losses, instrumentation, luminosity	3779
	O.R. Jones CERN, Geneva, Switzerland
	The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. This talk will comment on all of these systems and on their contributions to the various stages of beam commissioning. It will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; synchrotron light diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.
	Slides FRXCA01 [7.322 MB]

Paper

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MOODA02

S1-Global Module Tests at STF/KEK

cavity, cryomodule, SRF, linac

38

D. Kostin, K. Jensch, L. Lilje, A. Matheisen, W.-D. Möller, P. Schilling, M. Schmökel, N.J. Walker, H. Weise
DESY, Hamburg, Germany
C. Adolphsen, C.D. Nantista
SLAC, Menlo Park, California, USA
M. Akemoto, S. Fukuda, K. Hara, H. Hayano, N. Higashi, E. Kako, H. Katagiri, Y. Kojima, Y. Kondo, T. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakai, H. Nakajima, K. Nakanishi, S. Noguchi, N. Ohuchi, T. Saeki, M. Satoh, T. Shidara, T. Shishido, T. Takenaka, A. Terashima, N. Toge, K. Tsuchiya, K. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, K. Yokoya
KEK, Ibaraki, Japan
T.T. Arkan, S. Barbanotti, M.A. Battistoni, H. Carter, M.S. Champion, A. Hocker, R.D. Kephart, J.S. Kerby, D.V. Mitchell, T.J. Peterson, Y.M. Pischalnikov, M.C. Ross, W. Schappert, B.E. Smith
Fermilab, Batavia, USA
A. Bosotti, C. Pagani, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy

S1-Global collaborative effort of INFN, DESY, FNAL, SLAC and KEK, recently successfully finished at KEK as a part of ILC GDE, is an important milestone for the ILC. International collaboration of three regions, Asia, North America and Europe, proved to be efficient on the construction and cold tests of the accelerating module consisting of 8 SRF cavities; 2 from FNAL, 2 from DESY and 4 from KEK. Three different cavity tuning systems were tested together with two types of high power couplers. The module was cooled down three times which enabled extensive high power tests with cavities, performance limits investigation, Lorentz force detuning tests, simultaneous multiple cavities operation and other activities such as an operation test of distributed RF scheme with low level RF feedback. The results of this S1-Global module test are presented and discussed.

Slides MOODA02 [2.982 MB]

MOPC077

Commissioning of Multibunch Feedback Systems at the Fast Ramping Stretcher Ring ELSA

kicker, synchrotron, cavity, booster

250

A. Roth, F. Frommberger, N. Heurich, W. Hillert, M. Schedler, R. Zimmermann
ELSA, Bonn, Germany

Funding: Supported by German Research Foundation through SFB/TR 16 and by Helmholtz Alliance through HA-10¹.
At the Electron Stretcher Facility ELSA of Bonn University, an external beam of either unpolarized or polarized electrons is supplied to hadron physics experiments. The ELSA stretcherring operates in the energy range of 1.2 to 3.5 GeV and achieves a duty cycle of up to 80% using a fast energy ramp of 4 GeV/s. Under these conditions, an increase of the internal beam current from an actual value of 20 mA up to 200 mA is planned. Such an upgrade is mainly limited by the excitation of multibunch instabilities. As one active counteraction, we have installed state-of-the-art bunch-by-bunch feedback systems for the longitudinal, as well as for both transverse planes. The detailed setup with all main components and first results of the commissioning of the systems will be presented. In particular, the performance of the longitudinal feedback with a stabilized synchrotron frequency during the fast energy ramp will be discussed.

MOPC146

Development of Timing Distribution System with Femto-second Stability

linac, controls, acceleration, laser

421

T. Naito, K. Ebihara, S. Nozawa, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
M. Amemiya
AIST, Tsukuba, Japan

A timing distribution system with femto-second stability has been developed for the RF synchronization of accelerator and the laser synchronization of the pump-probe experiments. The system uses a phase stabilized optical fiber(PSOF) and an active fiber length stabilization. The PSOF has 5 ps/km/degC of the temperature coefficient. The active fiber length stabilization uses the phase detection of the round-trip sinusoidal wave and the fiber stretcher for the compensation of the fiber length. In this paper, we present the test results on a 500 m long signal distribution. The preliminary results of the timing stability are 20 fs at several minutes and 100 fs at four days, respectively.

MOPC148

Optical Clock Distribution System at the ALICE Energy Recovery Linac

pick-up, laser, electron, FEL

427

T.T. Ng, S.P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Highly stable clock distribution across future light sources is important for the synchronisation of beam generation, manipulation and diagnostics with photon experiments. Optical fibre technology can be used to combat the stability challenges in distributing clock signals over long distances with coaxial cable. We report here on the status of the optical clock distribution system installed on the ALICE energy recovery linac which uses the propagation of ultra-short optical pulses to carry the clock signal. We also present the characterisation of a beam arrival monitor suitable using <40 pC bunch charges and 7 mW, sub-100 fs distributed clock pulses.

MOPC154

RF Photo Gun Stability Measurement at PITZ

gun, laser, cavity, electron

442

I.I. Isaev, H.-J. Grabosch, M. Gross, L. Hakobyan, Ye. Ivanisenko, G. Klemz, W. Köhler, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, F. Stephan, G. Vashchenko, S. Weidinger, R.W. Wenndorff
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
M.A. Khojoyan
YerPhI, Yerevan, Armenia
D. Richter
HZB, Berlin, Germany
A. Shapovalov
NRNU MEPHI, Moscow, Russia
I.H. Templin, I. Will
MBI, Berlin, Germany

The stability of the RF phase in the RF photo injector gun is one of the most important factors for the successful operation of linac based free-electron lasers. Instabilities in the RF launch phase can significantly reduce the beam quality. Investigation on the dependence of different gun parameters and selection of optimal conditions are required to achieve high RF gun phase stability. The phase stability of the RF field is measured using the phase scan technique. Measurements were performed for different operating conditions at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). Obtained stability measurement results will be presented and discussed.

MOPC155

Performance of the Micro-TCA Digital Feedback Board for DRFS Test at KEK-STF

cavity, controls, klystron, LLRF

445

T. Miura, D.A. Arakawa, S. Fukuda, E. Kako, H. Katagiri, T. Matsumoto, S. Michizono, Y. Yano
KEK, Ibaraki, Japan

The test of distributed RF scheme (DRFS) for ILC was carried out at the superconducting RF test facility in KEK (KEK-STF). The LLRF system and two klystron units were installed in the same tunnel as SRF cavities. The vector-sum control for two cavities was done by using the micro-TCA digital feedback board. This board was the same one developed for the compact-ERL at KEK, but the software was changed for pulse operation. The result of the performance will be reported.

MOPC156

Operation Test of Distributed RF System with Circulator-less Waveguide Distribution in S1-Global Project at STF/KEK

cavity, klystron, superconducting-cavity, linac

448

T. Matsumoto, M. Akemoto, D.A. Arakawa, S. Fukuda, H. Honma, E. Kako, H. Katagiri, S. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan

Distributed RF System (DRFS) is one candidate for a single main linac tunnel design of International International Linear Collider (ILC). In the DRFS, more than ten 800-kW klystrons having a modulating anode are operated by a common DC power and a modulation anode modulator. Each klystron feeds its power into two superconducting cavities and its waveguide distribution system is configured without circulators. This DRFS consists of four SC cavities, two klystrons and a modulator was demonstrated in S1-Global project. The results of circulator-less operation in the DRFS will be reported.

MOPC164

Upgrade of the ISIS Synchrotron Low Power RF System

cavity, controls, ion, synchrotron

466

A. Seville, N.E. Farthing, I.S.K. Gardner, R.J. Mathieson, J.W.G. Thomason
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
D.B. Allen
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The ISIS synchrotron at the Rutherford Appleton Laboratory in the UK now routinely uses a dual harmonic RF system to accelerate beam currents in excess of 230 uA to run two target stations simultaneously. In order to give more stable control of the phase of the RF voltage at each of the fundamental (1RF) and second harmonic (2RF) cavities, changes have been made to the low power RF (LPRF) control systems. In addition to this a new FPGA based master oscillator has been commissioned for the first time, and further changes using digital technologies to replace other components of the LPRF system are to be investigated. This paper reports on the LPRF hardware commissioning and reliability.

MOPC166

Low RF Control Feedback and IQ Vector Modulator Compensation Functions

controls, linac, gun, coupling

472

M.G. Fedurin, R. Malone, V. Yakimenko
BNL, Upton, Long Island, New York, USA

IQ vector modulator is key element of the gun and linac RF control circuits at Accelerator Test Facility at Brookhaven National Laboratory. IQ modulator calibration procedure was developed to find proper compensation functions in the conversion algorithm to minimize phase-amplitude coupling and setting-reading errors: rms(A_set - A_read )= 0.03dB, rms(Phi_set - Phi_read) = 0.3 deg. Since stabilization of the RF phase and amplitude is become critical for many experiments the slow feedback was developed and applied as well to significantly compensate drifts in RF system.

MOPO001

Interaction Point Feedback Design and Integrated Simulations to Stabilize the CLIC Final Focus*

controls, simulation, quadrupole, ground-motion

475

G. Balik, L. Brunetti, G. Deleglise, A. Jeremie, L. Pacquet
IN2P3-LAPP, Annecy-le-Vieux, France
A. Badel, B. Caron, R. Le Breton
SYMME, Annecy-le-Vieux, France
A. Latina, J. Pfingstner, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) accelerator has strong precision requirements on offset position between the beams. The beam which is sensitive to ground motion needs to be stabilized to unprecedented requirements. Different Beam Based Feedback (BBF) algorithms such as Orbit Feedback (OFB) and Beam-Beam Offset Feedback (BBOF) have been designed. This paper focuses on the BBOF control which could be added to the CLIC baseline. It has been tested for different ground motion models in the presence of noises or disturbances and uses digital linear control with or without an adaptive loop. The simulations demonstrate that it is possible to achieve the required performances and quantify the maximum allowed noise level. This amount of admitted noises and disturbances is given in terms of an equivalent disturbance on the position of the magnet that controls the beam offset. Due to the limited sampling frequency of the process, the control loop is in a very small bandwidth. The study shows that these disturbances have to be lowered by other means in the higher frequency range.

MOPO002

Fast Orbit Correction for the ESRF Storage Ring

power-supply, storage-ring, diagnostics, controls

478

E. Plouviez, F. Epaud, J.M. Koch, K.B. Scheidt
ESRF, Grenoble, France

Today, at the ESRF, the correction of the orbit position is performed with two independent systems: one to deal with the slow movements and one to correct the motion in a range of up to 200Hz but with a limited number of fast BPMs and steerers. This later will be removed and one unique system will cover the frequency range from DC to 200Hz using all the 224 BPMs and the 96 steerers. Indeed, thanks to the procurement of the Liberas Brilliance and installation of new AC power supplies, it is now possible to access all the Beam positions at a frequency of 10 kHz and to drive a small current in the steerers in a 400Hz bandwidth. The first tests of correction of the beam position have been performed and will be presented. This new orbit correction system is also a powerful diagnostics system: the measurement and survey of the Ring's lattice parameters is possible thanks to the high measurement rate of very high resolution position data. Results of this will also be presented.

MOPO003

A Broadband RF Stripline Kicker for Damping Transversal Multibunch Instabilities

kicker, impedance, single-bunch, damping

481

M. Schedler, D. Heiliger, W. Hillert, A. Roth
ELSA, Bonn, Germany

When operating an RF feedback system, being able to reliably act upon every single bunch is a necessity. By employing a broadband RF stripline kicker, any bunch displacement can be corrected for. In a 500 MHz accelerator, the decay time of the electromagnetic field inside the kicker has to be less than 2 ns in order to avoid the following bunch to be affected. By designing the kicker as an RF coax device matched to the line impedance of the power cables, perturbing reflected signals are avoided. Additionally, the kicking strength and thus the shunt impedance should be maximized over the full spectrum from DC to 250 MHz. The kicker design has been optimized to meet the above requirements by relying on CST Microwave Studio simulations. Their results and first measurements are presented.

MOPO004

A Longitudinal Kicker Cavity for a Bunch-by-bunch Feedback System at ELSA

cavity, kicker, simulation, impedance

484

N. Heurich, W. Hillert, A. Roth, R. Zimmermann
ELSA, Bonn, Germany

At the Electron Stretcher Facility ELSA of Bonn University, a longitudinal bunch-by-bunch feedback system is currently being installed in order to damp multibunch instabilities and to enable a future intensity upgrade of up to 200 mA. As a main component, a longitudinal kicker cavity was developed and manufactured. The kicker requires a bandwidth of 250~MHz taking into account the bunch spacing of 2 ns at ELSA. Existing designs used at other facilities were optimized in view of the considerably larger bunch lenght at ELSA. The choice of 1.125 GHz as a center frequency is a result of these considerations. With the resulting low quality factor, the design had to be optimized in order to maximize the shunt impedance. The longitudinal feedback is succesfully working with the prototype installed in the stretcher ring. The design and detailed simulations of the geometry are discussed and laboratory measurements are presented.

MOPO005

A Transverse Feedback System using Multiple Pickups for Noise Minimization

kicker, pick-up, synchrotron, betatron

487

M. Alhumaidi, A.M. Zoubir
TU Darmstadt, Darmstadt, Germany

A new concept for using multiple pickups for estimating beam angle at the kicker is addressed. The estimated signal should be the driving feedback signal. The signals from the different pickups are delayed, such that they correspond to the same bunch. Consequently a weighted sum of the delayed signals is suggested as an estimator of the beam angle at the kicker. The weighting coefficients are calculated such that the estimator is unbiased, i.e. the output corresponds to the actual beam angle at the kicker for non-noisy pickup signals. Furthermore, the estimator must give the minimal noise power at the output among all linear unbiased estimators. Finally results for the heavy ions synchrotron SIS 18 at the GSI are shown.

MOPO006

DAΦNE Bunch-by-bunch Feedback Upgrade as SuperB Design Test

diagnostics, factory, controls, luminosity

490

A. Drago
INFN/LNF, Frascati (Roma), Italy
D. Teytelman
Dimtel, San Jose, USA

DAΦNE, the PHI-factory located in Frascati, has always shown dynamic behavior strongly dependent on the bunch-by-bunch feedback, since its first runs in 1997. Over the years, to keep up with the evolving machine requirements, transverse and longitudinal systems have received multiple upgrades and updates. During fall 2010, all the six DAΦNE feedback systems have been upgraded to support the next run for KLOE as well as to test bunch-by-bunch feedback architectures intended for the future Italian SuperB factory. Both e+/e^- longitudinal feedback systems have been completely replaced with new hardware for increased reliability, better diagnostics and improved maintainability. In the effort to reduce residual dipole beam motion, determined by the front-end and quantization noise floor, vertical feedback systems now feature a 12-bit ADC, in place of the older 8-bit design. In the paper, we describe the hardware and software changes of this upgrade. Feedback performance analysis and beam dynamics data collected by the systems are presented.

MOPO007

Resonant Strip-line Type Longitudinal Kicker

kicker, simulation, impedance, wakefield

493

T. Nakamura
JASRI/SPring-8, Hyogo-ken, Japan

The longitudinal feedback for the SPring-8 storage ring is under consideration as the device for suppression of the longitudinal instabilities driven by higher order modes of cavities, observed at test operation with 4 to 6 GeV low energy beam. As the beam energy and the ring circumference are rather high, and the length of the space for the longitudinal kickers is limited, high efficiency kicker per length is required in the our case. As a candidate of such kicker, we propose a resonant strip-line type longitudinal kicker with drive frequency of 13/4 of RF frequency. The shut impedance per length is higher than over-loaded cavities and the drive circuits can be simplified because of higher drive frequency. The design consideration, the result of the simulation and measurement of the prototype model, and the detail of the drive circuit will be reported in the presentation.

MOPO008

Design and Simulation of the Transverse Feedback Kicker for the HLSⅡ

kicker, impedance, simulation, vacuum

496

W.B. Li, P. Lu, B.G. Sun, F.F. Wu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to suppress the coupled bunch instabilities in the HLSⅡ storage ring, a transverse feedback system is required. The vital component of the system is the kicker that is the feedback actuator. We design a stripline kicker for the HLSⅡ. The horizontal and vertical electrodes are combined in a structure on account of the space limit. In addition to the design issues, this paper focuses on the simulation results for the kicker using the computer codes. By the 2D code POSSION, we calculate and optimize the characteristic impedance of the stripline kicker to match the 50Ω external transmission lines so as to reduce the reflected power. The reflection coefficient and the shunt impedance in the working frequency range are obtained by the 3D code HFSS. The simulation results provide many important supports for the structure design.

MOPO010

Orbit Feedback System for the MAX IV 3 GeV Storage Ring

vacuum, power-supply, storage-ring, simulation

499

M. Sjöström, J. Ahlbäck, M.A.G. Johansson, S.C. Leemann, R. Nilsson
MAX-lab, Lund, Sweden

The paper describes the current orbit correction system design for the 3 GeV storage ring at the MAX IV laboratory, a light source facility under construction in Lund, Sweden. The orbit stability requirements for the 3 GeV storage ring are tight at roughly 200 nm vertical position stability in the insertion device (ID) straight sections. To meet this the ring will be equipped with 200 beam position monitors (BPMs) and 380 dipole corrector magnets, 200 in the horizontal and 180 in the vertical plane. The feedback loop solution, one slow orbit feedback (SOFB) loop and one fast orbit feedback (FOFB) loop in fast acquisition mode at 10,000 samples/second, will be presented. The paper will also discuss the various boundary conditions specific to the MAX IV 3 GeV storage ring design, such as a Cu vacuum chamber, and the impact on the corrector design.

MOPO012

LHC Damper Beam Commissioning in 2010

damping, injection, kicker, ion

505

W. Höfle, G. Kotzian, M. Schokker, D. Valuch
CERN, Geneva, Switzerland

The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics have become part of the standard operations procedure. The system proved important to limit emittance blow-up at injection and maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for proton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap cleaning and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.

MOPO013

Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment

pick-up, emittance, betatron, simulation

508

W. Höfle, G. Arduini, R. De Maria, G. Kotzian, D. Valuch
CERN, Geneva, Switzerland
V.A. Lebedev
Fermilab, Batavia, USA

The LHC transverse dampers initially build to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noises at the frequencies of betatron sidebands. To prevent the emittance growth excited by magnet noise using the damper this system has to have extremely low noise properties. The paper discusses simulation results on the effectiveness of the transverse feedback system to suppress such oscillations and the experimental results from a damper point of view as they were gained during the 2010 LHC run. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.

MOPO014

SVD-based Filter Design for the Trajectory Feedback of CLIC

ground-motion, luminosity, controls, simulation

511

J. Pfingstner, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland
M. Hofbaur
UMIT, Hall in Tirol, Austria

The orbit feedback of the Compact Linear Collider (CLIC) is the basic counter-measure against ground motion effects below 1 Hz in the beam delivery system and the main linac of CLIC. In this paper we present significant improvements of the orbit feedback design, by using time-dependent and spatial filters. The design procedure is based on a singular value decomposition (SVD) of the orbit response matrix and on loop-shaping techniques. This modified design has essential advantages compared to previous ones. The required beam position monitor resolution in the beam delivery system could be relaxed by a factor of five. At the same time the suppression of ground motion effects is improved. As a consequence, the tight tolerances for the allowable luminosity loss due to ground motion effects in CLIC can be met. The presented methods can be easily adapted to other accelerators in order to relax sensor tolerances and to efficiently suppress ground motion effects.

MOPO015

Operation Status of Bunch-by-bunch Feedback System in the TLS

controls, injection, diagnostics, kicker

514

C.H. Kuo, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao
NSRRC, Hsinchu, Taiwan

There are several FPGA based bunch-by-bunch feedback systems that were deployed in the Taiwan Light Source now. They play various roles to suppress beam instability. By using SPring-8 designed feedback processors is pioneer to apply in the storage ring of TLS successfully and help Dimtel system to be quick commission. The Dimtel feedback system provide a life spare unit and explore to control system integration especially to the EPICS toolkit system. Rich functionality includes of excitation of individual bunch or specifies bunches, averaged spectrum, tune measurement by the feedback dip in the averaged spectrum. Operation status of the system will be summary in this report.

MOPO016

Commissioning Tune Feedback in the Taiwan Light Source

insertion, insertion-device, controls, undulator

517

C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The tune control is important parameter in the insertion devices operation. There are many difference type insertion devices are disturbed in the storage ring of TLS. The traditional feed-forward control to correct orbit change and tune shift that isn’t enough when difference type insertion devices are operated with various condition. The tune feedback is used to solve the tune change problem. The stable tune measurement is necessary in the stable storage ring. There are various excited bunch train methods to get stable tune that will be also discussed in this report.

MOPO017

Latest Performance Results from the FONT5 Intra-train Position and Angle Feedback System at ATF2

kicker, linear-collider, collider, positron

520

G.B. Christian, D.R. Bett, M.R. Davis, C. Perry
JAI, Oxford, United Kingdom
R. Apsimon, P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Constance, A. Gerbershagen
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-to-bunch timescales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. An overview of the hardware, and the latest results from beam tests at ATF2, will be presented. A total system latency as low as approximately 140 ns has been demonstrated.

MOPO018

Active Beam Current Stabilization in the Cornell ERL Prototype Injector

laser, gun, cavity, cathode

523

F. Löhl, P. Szypryt
CLASSE, Ithaca, New York, USA

In order to operate the Cornell ERL prototype injector at beam currents beyond 10 mA, the beam current has to be highly stable. The reason is that fast beam current fluctuations generate transient effects in the DC gun voltage as well as in the fields of subsequent superconducting cavities, which can lead to excessive beam loss or to trips of subsystems. Therefore, a feedback scheme was developed which uses the signal of a beam current monitor as an input, and applies appropriate corrections to a Pockels cell installed within the laser path of the photo-injector laser. In this paper, high current results achieved with this feedback scheme are presented.

MOPO022

Precision Beam Instrumentation and Feedback-Based Beam Control at RHIC

coupling, acceleration, controls, resonance

526

M.G. Minty, W. Fischer, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, T. Roser, V. Schoefer, S. Tepikian, M. Wilinski
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this report we present advances in beam instrumentation required for feedback-based beam control at the Relativistic Heavy Ion Collider (RHIC). Improved resolution has contributed to enabling now routine acceleration with multiple feedback loops. Better measurement and control of the beam’s properties have allowed acceleration at a new working point and have facilitated challenging experimental studies.

MOPO026

Design, Manufacturing and Tests of Closed-loop Quadrupole Mover Prototypes for European XFEL

quadrupole, controls, alignment, vacuum

535

J. Munilla, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, T. Martínez de Alvaro, E. Molina Marinas, S. Sanz, F. Toral, C. Vazquez
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009
In this report the development of a quadrupole mover with submicron repeatability is reported, which will be used in the intersections of the Undulator Systems of the European XFEL (EXFEL). It is part of the Spanish in-kind contribution to this facility. The main specifications include submicron repeatability for a 70 kg quadrupole magnet within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear actuators based on 5-phase stepping motors have been chosen. Vertical actuator works in a wedge configuration to take mechanical advantage. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one LVDT sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. Prototyping stage is done and a serial production of more than 90 devices is expected, so intense work has been done to achieve a reliable industrial production and validation. In this report, results of mechanical measurements including reproducibility, tests of different operation strategies and critical situations will be reported.

MOPO027

Status of a Study of Stabilization and Fine Positioning of CLIC Quadrupoles to the Nanometre Level*

quadrupole, alignment, controls, damping

538

K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, S.M. Janssens, A.M. Kuzmin, R. Leuxe, R. Moron Ballester
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no.227579
Mechanical stability to the nanometre and below is required for the CLIC quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterization of vibration sources was extended to forces acting directly on the magnet, such as water-cooling induced vibrations. This paper shows the achievements, improvements, and an outlook on further R&D.

MOPO029

Validation of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider using a Test Setup (Mock-up) with 5 Degrees of Freedom

quadrupole, alignment, target, controls

544

H. Mainaud Durand, M. Anastasopoulos, J. Kemppinen, R. Leuxe, M. Sosin, S. griffet
CERN, Geneva, Switzerland

The CLIC main beam quadrupoles need to be pre-aligned within 17μm rms with respect to a straight reference line along a sliding window of 200 m. A re-adjustment system based on eccentric cam movers, which will provide stiffness to the support assembly, is being studied. The cam movers were qualified on a 1 degree of freedom (DOF) test setup, where a repeatability of adjustment below 1 μm was measured along their whole range. This paper presents the 5 DOF mock-up, built for the validation of the eccentric cam movers, as well as the first results of tests carried out: resolution of displacement along the whole range, measurements of the support eigenfrequencies.

MOPO039

B-train Performances at CNAO

dipole, synchrotron, power-supply, extraction

568

M. Pezzetta, G. Bazzano, E. Bressi, L. Falbo, C. Priano, M. Pullia
CNAO Foundation, Milan, Italy
O. Coiro, G. Franzini, D. Pellegrini, M. Serio, A. Stella
INFN/LNF, Frascati (Roma), Italy
G. Venchi
University of Pavia, Pavia, Italy

The commissioning of CNAO, the Italian Centre of Oncological Hadrontherapy, with proton beams is completed. The real-time measurement of the synchrotron dipole field with the so-called B-train, together with its electronic systems and related software and firmware are here described. An additional magnet, powered in series with the synchrotron dipoles, is equipped with a special coil that measures the field integral variation along the beam nominal path. The voltage induced in the coil is digitized with a fast ADC and numerically integrated by an FPGA. The field integral is then distributed to the users every time that the equivalent field changes by 0.1 G. The measured B field ranges from 0 to 1.6 T with maximum ramps of 3 T/s. The B-train system will be used to provide feedback in field to the dipole power supply. It will handle the limited bandwidth of the active filter, the B-field lag in the magnets and will avoid current jumps.

MOPS049

Study of Ion-induced Instabilities and Transverse Feedback Performance at SOLEIL

ion, vacuum, simulation, electron

712

R. Nagaoka, L. Cassinari, M.D. Diop, J.-M. Filhol, M.-P. Level, A. Loulergue, P. Marchand, R. Sreedharan
SOLEIL, Gif-sur-Yvette, France

Experimental studies indicate that the SOLEIL storage ring at its maximum designed current of 500 mA is under a large influence of ions, potentially capable of inducing the so called fast beam-ion instability. To avoid it, the following three conditions have been empirically found effective: A reduced RF voltage, uniform filling and a large vertical chromaticity. While the choice of uniform filling appears contradictory to raising the ion instability threshold, it goes well with lowering of the RF voltage if outgassing due to beam-induced heating of the vacuum components is the primary source of ions. Additional difficulties associated are frequent occurrence of sudden beam blowups despite the presence of transverse feedback, which are large enough to trigger machine interlocks leading to complete beam losses. These blow ups may even take place horizontally inside in-vacuum insertion devices. The present paper reports on the results and findings obtained through experimental and simulation studies carried out on the collective beam dynamics and the transverse feedback performance, which are deeply interlinked, in order to clarify the mechanism of the encountered phenomena.

MOPS084

Status of Electron Cloud Dynamics Measurements at CESRTA*

dipole, electron, betatron, damping

799

M.G. Billing, G. Dugan, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, J.P. Sikora, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
J.Y. Chu
CMU, Pittsburgh, Pennsylvania, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA

Funding: Supported by US National Science Foundation (PHY-0734867) & Dept. of Energy (DE-FC02-08ER41538)
The study of electron cloud-related instabilities for the CESR-TA project permits the observation of the interaction of the electron cloud with the stored beam under a variety of accelerator conditions. These measurements are undertaken utilizing automatic and semi-automatic techniques for three basic observations: the measurement of tune shifts of individual bunches along a train, the detection of the coherent self-excited spectrum for each bunch within a train and the pulsed excitation of either the betatron dipole or head-tail mode for each individual bunch within the train, followed by the observation of the damping of its coherent motion. These techniques are employed to study the electron cloud-related interactions in a number of conditions, such as trains of bunches with low emittance and spaced by as little as 4 nsec between bunches. We report on the most recent observations and results.

MOPS089

Identification of Bunch Dynamics in the Presence of E-cloud and TMCI for the CERN SPS Ring

simulation, controls, coupling, kicker

811

O. Turgut, J.D. Fox, C.H. Rivetta, S. Uemura
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work is supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
Measurements and multi-particle simulation codes (i.e. HEAD-TAIL, WARP, CMAD) indicate that bunched particle beams show unstable motions induced by electron-clouds and strong head-tail interactions. The bunch dynamics exhibits highly non-linear, complex and unstable behavior under certain operating conditions. Feedback control systems have been proposed to mitigate these instabilities in the CERN SPS ring. The design of feedback systems requires the knowledge of a reduced dynamic model of the bunch. It allows to include and quantify the effect of noise and signal perturbations, as well as system robustness to parameter variation. Identification techniques are used to estimate those models based on bunch motion measurements. In this work we present reduced mathematical models representing the transverse bunch dynamics and identification techniques to extract the model parameters based on measurements. These techniques are validated using time domain simulations of the bunch motion conducted using multi-particle simulation codes. For that, different sections of the bunch are driven by random signals, and the vertical motion of those areas is used to estimate the reduced model.

TUODA01

Vertical Emittance Reduction and Preservation at the ESRF Electron Storage Ring

emittance, coupling, quadrupole, storage-ring

928

A. Franchi, J. Chavanne, F. Ewald, L. Farvacque, T.P. Perron, K.B. Scheidt
ESRF, Grenoble, France

In 2010 a campaign for the reduction and preservation of low vertical emittance at the ESRF electron storage ring was undertaken: values between 20 and 30 pm have been dramatically reduced to 3.5-4.5 pm, even during beam delivery. This improvement is the result of an increased measurement precision provided by the recently upgraded beam position monitoring system, a new correction algorithm, a larger number of correctors and two independent schemes for the automatic compensation of coupling induced by a few insertion devices whenever their gaps are moved by users during beam delivery. This paper summarizes the campaign's milestones and the results updated to the first half of 2011.

Slides TUODA01 [5.297 MB]

TUPC014

System Control for the CLIC Main Beam Quadrupole Stabilization and Nano-positioning*

quadrupole, luminosity, ground-motion, simulation

1021

S.M. Janssens, K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, A.M. Kuzmin, R. Leuxe, J. Pfingstner, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland

The conceptual design of the active stabilization and nano-positioning of the CLIC main beam quadrupoles was validated in models and experimentally demonstrated on test benches. Although the mechanical vibrations were reduced to within the specification of 1.5 nm at 1 Hz, additional input for the stabilization system control was received from integrated luminosity simulations that included the measured stabilization transfer functions. Studies are ongoing to obtain a transfer function which is more compatible with beam based orbit feedback; it concerns the controller layout, new sensors and their combination. In addition, the gain margin must be increased in order to reach the requirements from a higher vibration background. For this purpose, the mechanical support is adapted to raise the frequency of some resonances in the system and the implementation of force sensors is considered. Furthermore, this will increase the speed of repositioning the magnets between beam pulses. This paper describes the improvements and their implementation from a controls perspective.

TUPC023

Status of Ground Motion Mitigation Techniques for CLIC

luminosity, quadrupole, simulation, ground-motion

1048

J. Snuverink, K. Artoos, C.G.R.L. Collette, F. Duarte Ramos, A. Gaddi, H. Gerwig, S.M. Janssens, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
G. Balik, L. Brunetti, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Caron
SYMME, Annecy-le-Vieux, France
J. Resta-López
IFIC, Valencia, Spain

The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques are proposed - quadrupole stabilisation and positioning, final doublet stabilisation as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of the ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) have been performed, which model the hardware and beam performance in detail. Based on the results future improvements of the mitigation techniques are suggested and simulated. It is shown that with the current design the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed.

TUPC027

CLIC Post-Collision Line Luminosity Monitoring

photon, luminosity, simulation, monitoring

1057

R. Appleby
UMAN, Manchester, United Kingdom
A. Apyan, L.C. Deacon, E. Gschwendtner
CERN, Geneva, Switzerland

The CLIC post collision line is designed to transport the un-collided beams and the products of the collided beams with a total power of 14 MW to the main beam dump. Full Monte Carlo simulation has been done for the description of the Compact Linear Collider (CLIC) luminosity monitoring at the post collision line. One method of the luminosity diagnostic is based on the detection of high energy muons produced by the beamsstrahlung photons in the main beam dump. The disrupted beam and the beamsstrahlung photons produce at the order of 10⁶ muons per bunch crossing, with energies greater than 10 GeV. Currently threshold Cherenkov counters are considered after the beam dump for the detection of these high energy muons. A second method using the direct detection of the beamsstrahlung photons is also considered.

TUPC068

SOLEIL Beam Orbit Stability Improvements

booster, synchrotron, photon, power-supply

1156

N. Hubert, Y.-M. Abiven, F. Blache, F. Briquez, L. Cassinari, J.-C. Denard, J.-F. Lamarre, P. Lebasque, N. Leclercq, A. Lestrade, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

The electron beam orbit stability has been significantly improved at synchrotron SOLEIL. Low frequency noise sources have been localized and identified: the fans installed on the storage ring to cool down the ceramic chambers of the kickers, shaker and FCT, were slightly wobbling the electron beam orbit at 46, 50, 54 and 10⁸ Hz. The localization method and the solutions that will allow reducing the noise from 0.8 μm RMS down to 0.3 μm are presented. Besides, a new 160 m long beamline, NANOSCOPIUM, is being installed on a canted straight section. Its photon beam position stability requirements are very tight calling for the following improvements: addition of 2 more BPMs and fast correctors in the orbit feedback loops, new INVAR stands for BPM and XBPM integrating Hydrostatic Level System sensors. The paper is also discussing other projects that did or will contribute to improving the beam orbit stability: installation of 145 temperature sensors on the storage ring, a new analog feedforward correction system for insertion devices, and the use of the bending magnet X-BPM measurements in the slow and fast orbit feedback loops.

TUPC089

New Digital NMR System for an Old Analyzing Magnet

controls, power-supply, cyclotron, resonance

1215

Z. Kormány, I. Ander
ATOMKI, Debrecen, Hungary

The analyzing magnet of the ATOMKI cyclotron measures the beam energy with high precision and can lower its energy spread to ~5x10^-4. The highly stable magnetic field is achieved by a NMR-feedback in the control loop of the power supply. The original analog system was designed and built over 25 years ago applying mainly obsolete, partly nowadays unavailable components. Maintaining and keeping the system running required increasing efforts every year. A new digital system has been developed to replace the old one. Except the high-frequency signal domain (HF oscillator and preamplifier) it performs every processing digitally. Its heart is a mixed-signal microcontroller that generates the signals for the NMR-probe, measures the amplitude and frequency of the oscillation, evaluates the demodulated signal and controls the power supply. A fast NMR-pulse detection algorithm was developed; as a result the embedded program can perform all measuring, detecting and controlling tasks in real-time. A PC connects to the controller, sends commands and displays the received signals and status data. The control software allows easy handling of the complete system with nearly automated operation.

TUPC103

Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR

injection, kicker, betatron, quadrupole

1254

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
M. Takagi
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
M. Tejima, T. Toyama
KEK, Ibaraki, Japan

The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC107

Some Preliminary Experiments using LIBERA BPMs in BEPCII*

coupling, resonance, injection, kicker

1266

Y. Zhang, H.Z. Ma, J. Yue
IHEP Beijing, Beijing, People's Republic of China

Funding: Supported by the National Natural Science Foundation of China (10805051)
There are total 16 LIBERA BPMs in BEPCII, which is a double ring e⁺e⁻ collider. The turn-by-turn BPMs serve as only tune measurement system in most cases during normal operation. We tried to do some more machine study using them: the local coupling parameter at the BPM, the resonance driving term, the decoherence parameter which could be used to calibrate the strength of octupole in the ring. We also compare the difference from the different exciting method: single time kick with injection kicker or sinusoidal kick with feedback system.

TUPC112

Photon Beam Position Monitor based on Position-sensitive Detector for HLS*

photon, synchrotron, injection, diagnostics

1281

Y.Y. Xiao, L.M. Gu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to overcome the limitation that the existing photon beam position monitors (PBPM) cannot measure the beam position in vertical and horizontal at the same time, a new photon beam position monitor based on position-sensitive detector (PSD) has developed at HLS (Hefei Light Source). The new PBPM based on the PSD has very fast response speed, high sensitivity and wide dynamic range. This PBPM system also includes the C4674 signal processing circuit, NI USB-9215 data acquisition device and the LABVIEW data acquisition program. This PBPM system has been calibrated vertically and horizontally on-line, then has been applied in the beam line B3EA of HLS to measure the position of the synchrotron light. Some results are given.

TUPC116

Beam Diagnostics Global Data Warehouse Implementation and Application at SSRF*

diagnostics, EPICS, controls, monitoring

1287

Y.B. Leng, Z.C. Chen, Y.B. Yan, R.X. Yuan
SSRF, Shanghai, People's Republic of China

A fully functional beam diagnostics system has been developed at SSRF serving user operation and machine study since 2009. Global orbit disturbances, BPM failures and DCCT noise signal have been observed randomly. Without correct event trigger it is hard to capture real time data and analyze the cause of the above failures. A BI global data warehouse has been implemented as a solution to buffer online data and do correlation analyze at SSRF.

TUPC117

Embedded EPICS IOC Data Acquisition System for Beam Instability Research

betatron, wakefield, EPICS, storage-ring

1290

N. Zhang, Y.B. Leng
SSRF, Shanghai, People's Republic of China

Funding: This research is supported by National Natural Science Fund(No.Y155131061).
To be a part of beam diagnostics system in SSRF 3.5 GeV electron storage ring, a high performance oscilloscope is introduced to build a bunch by bunch data acquisition and processing dedicated system, which is mainly used to observe individual bunch position in transverse plane and bunch charge. By analysis of Betatron oscillation amplitude distribution and corresponding filling pattern, we hope to find phenomenon about multi-bunch Wakefield effect[1] on beam Betatron oscillation for beam instability research. The system is configured as a scope IOC, and integrated into the EPICS based control system. Application of this system and some data analysis results are also discussed in this paper.

TUPC118

Test Results on Beam Position Resolution for Low-Q IP-BPM at KEK-ATF2

cavity, alignment, collider, dipole

1293

S.W. Jang, A. Heo, J.G. Hwang, E.-S. Kim, H.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
H.K. Park
CHEP, Daegu, Republic of Korea

We have performed the beam tests on the beam position resolution for the Low-Q IP-BPM (Interaction Point-Beam Position Monitor) at ATF2 which is an accelerator test facility for the International Linear Collider. The main goals of KEK-ATF2 are to achieve beam size of 37 nm and beam resolution of nano-meter for beam stabilization. Resolution tests for the Low-Q IP-BPM were performed with KEK BPM doublet in Jan. 2011. We got the results of beam position resolution 70 nm during the experimental periods and will present the detailed experimental procedures and results.

TUPC128

Transverse Beam Jitter Propagation in Multi-bunch Operation at ATF2

extraction, simulation, kicker, lattice

1320

J. Resta-López, J. Alabau-Gonzalvo
IFIC, Valencia, Spain
P. Burrows, G.B. Christian
JAI, Oxford, United Kingdom
B. Constance
CERN, Geneva, Switzerland

Pulse-to-pulse orbit jitter, if not controlled, can drastically degrade the luminosity in future linear colliders. The second goal of the ATF2 project at the KEK accelerator test facility is to stabilize the vertical beam position down to approximately 5% of the nominal rms vertical beam size at the virtual interaction point (IP). This will require control of the orbit to better than 1 micrometer at the entrance of the ATF2 final focus system. In this paper, by means of computer simulations, we study the vertical jitter propagation along the ATF2 from the start of the extraction line to the IP. For this study pulse-to-pulse vertical jitter measurements using three stripline beam position monitors are used as initial inputs. This study is performed for the case of a bunch-train with three bunches, but could easily be extended for a larger number of bunches. The cases with and without intra-train orbit feedback correction in the extraction line of ATF2 are compared.

TUPC144

Preliminary BPM Electrics Testing for the Taiwan Photon Source Project

injection, brilliance, controls, electron

1362

C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.-Y. Liao
NSRRC, Hsinchu, Taiwan

The preliminary BPM electrics are developing and testing for Taiwan Photon Source (TPS), is a 3 GeV synchrotron light source which being in construction at NSRRC. This new BPM electronics with integrated FPGA based hardware, and will be testing in the TLS (Taiwan Light Source) with real beam at first. The enhance functionality of current generation will be adopted in the TPS. The electronic prototype testing and relative property will be reported in this report.

TUPC157

Design and Initial Results of a Turn-by-Turn Beam Position Monitoring System for Multiple Bunch Operation of the ATF Damping Ring

injection, damping, single-bunch, extraction

1398

G.B. Christian, D.R. Bett, M.R. Davis, C. Perry
JAI, Oxford, United Kingdom
R. Apsimon, P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Constance, A. Gerbershagen
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

An FPGA-based monitoring system has been developed to study multi-bunch beam instabilities in the damping ring (DR) of the KEK Accelerator Test Facility (ATF), utilising a stripline beam position monitor (BPM) and existing BPM processor hardware. The system is designed to record the horizontal and/or vertical positions of up to three bunches in the DR in single-bunch multi-train mode or the head bunch of up to three trains in multi-bunch mode, with a bunch spacing of 5.6 ns. The FPGA firmware and data acquisition software were modified to record turn-by-turn data for up to six channels and 1–3 bunches in the DR. An overview of the system and initial results will be presented.

TUPC159

Energy Measurements with Resonant Spin Depolarisation at Diamond

electron, storage-ring, resonance, quadrupole

1404

I.P.S. Martin, M. Apollonio, R.T. Fielder, G. Rehm
Diamond, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

A precise knowledge of the electron beam energy is critical for the accurate determination of many light source parameters, such as momentum compaction factor, natural chromaticity, energy stability and undulator spectra. In common with other facilities, a method of energy measurement based on resonant spin depolarisation has been developed at Diamond. In this paper we report on progress towards storage ring characterisation using this method, as well as describing the diagnostics developments that have enabled these measurements to be made.

TUPC160

Recent Developments of Diagnostics at Diamond

photon, synchrotron, undulator, diagnostics

1407

G. Rehm, C. Bloomer, A.F.D. Morgan, C.A. Thomas
Diamond, Oxfordshire, United Kingdom

This contribution summarizes some recent development of diagnostics system to improve the operation of Diamond Light Source. Firstly, we are advancing the integration of photon beam diagnostics with the orbit feedback system. Measurements have shown the correlation between recorded electron and photon beam motion on the short timescales (ms-minutes) and the potential for improvement on long timescales (minutes-days). Secondly, with the addition of more elliptically polarized undulators at Diamond, measurement of their photon beam position require a solution that reliably operates with the changing photon beam profiles emitted by these devices. To this end, we have developed an X-ray beam position monitor that analyzes the backscatter from an aperture in the front end. Thirdly, as operation in low-alpha mode with few ps bunch lengths receives increasing interest from users, we have been evaluating various techniques for the measurement of these short bunch lengths that could serve as alternatives to streak camera measurements.

TUPS040

Driving the LHC Collimators' Stepping Motors over 1 km with High Accuracy avoiding EMI Effects

controls, impedance, beam-losses, radiation

1626

A. Masi, G. Conte, R. Losito, M. Martino
CERN, Geneva, Switzerland

The LHC collimators are exposed to very high levels of radiation, which means that the power drivers must be installed far from the stepping motors that they drive. Due to the geometry of the underground installations, the distances can be up to 1 km. The long cables that connect the drivers to the motors behave as transmission lines modifying dramatically the impedance seen by the drivers and consequently jeopardizing the control performance of Pulse Width Modulation (PWM) drivers. In this paper we address this problem, provide an analytical model of the driver-cable-motor system and describe the analog solution we have developed to improve the performance of a typical off the shelf driver. Finally we characterize the improvement of the performances with measurements of positioning repeatability and show that electromagnetic emissions from the long cables are drastically reduced, making the use of stepping motors compatible with extremely sensitive instrumentation such as the LHC Beam Loss Monitors (BLM).

TUPS059

SPS WANF Dismantling: A Large Scale-Decommissioning Project at CERN

radiation, shielding, target, ion

1668

S. Evrard, Y. Algoet, N. Conan, D. DePaoli, I. Efthymiopoulos, S. Fumey, H. Gaillard, J.L. Grenard, D. Grenier, A. Pardons, E. Paulat, Y.D.R. Seraphin, M. Tavlet, C. Theis, H. Vincke
CERN, Geneva, Switzerland

The operation of the SPS (Super Proton Synchrotron) West Area Neutrino Facility (WANF) was halted in 1998. In 2010 a large scale-decommissioning of this facility was conducted. Besides CERN’s commitment to remove non-operational facilities, the additional motivation was the use of the installation (underground tunnels and available infrastructure) for the new HiRadMat facility, which is designed to study the impact of high-intensity pulsed beams on accelerator components and materials. The removal of 800 tons of radioactive equipment and the waste management according to the ALARA (As Low As Reasonably Achievable) principles were two major challenges. This paper describes the solutions implemented and the lessons learnt confirming that the decommissioning phase of a particle accelerator must be carefully studied as from the design stage.

TUPZ010

Longitudinal Emittance Blow-up in the LHC

emittance, synchrotron, damping, acceleration

1819

P. Baudrenghien, A.C. Butterworth, M. Jaussi, T. Mastoridis, G. Papotti, E.N. Shaposhnikova, J. Tückmantel
CERN, Geneva, Switzerland

The LHC relies on Landau damping for longitudinal stability. To avoid decreasing the stability margin at high energy, the longitudinal emittance must be continuously increased during the acceleration ramp. Longitudinal blow-up provides the required emittance growth. The method was implemented through the summer of 2010. We inject band-limited RF phase-noise in the main accelerating cavities during the whole ramp of about 11 minutes. Synchrotron frequencies change along the energy ramp, but the digitally created noise tracks the frequency change. The position of the noise-band, relative to the nominal synchrotron frequency, and the bandwidth of the spectrum are set by pre-defined constants, making the diffusion stop at the edges of the demanded distribution. The noise amplitude is controlled by feedback using the measurement of the average bunch length. This algorithm reproducibly achieves the programmed bunch length of about 1.2 ns (4 σ) at flat top with low bunch-to-bunch scatter and provides a stable beam for physics coast.

TUPZ028

Beam Based Optimization of the Squeeze at the LHC

optics, beam-losses, simulation, controls

1867

X. Buffat
EPFL, Lausanne, Switzerland
M. Lamont, S. Redaelli, J. Wenninger
CERN, Geneva, Switzerland

The betatron squeeze is a critical operational phase for the LHC because it is carried out at top energy, with the maximum stored energy and with reduced aperture margins in the superconducting triplets. A stable operation with minimum beam losses must be achieved in order to ensure a safe and efficient operation. The operational experience at the LHC showed that this is possible. The operation in 2010 is reviewed. In particular, orbit, tune and chromaticity measurements are investigated and correlated to beam losses. Different optimizations are then proposed towards a more efficient and robust operation. The improvements obtained for the operation in 2011 are presented.

TUPZ035

RHIC Polarized Proton Status and Operation Highlights

polarization, resonance, emittance, controls

1888

H. Huang, L. A. Ahrens, I.G. Alekseev, E.C. Aschenauer, G. Atoian, M. Bai, A. Bazilevsky, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, A. Dion, K.A. Drees, W. Fischer, J.W. Glenn, X. Gu, L.T. Hoff, C. Liu, Y. Luo, W.W. MacKay, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, M.G. Minty, C. Montag, J. Morris, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, D. Smirnov, S. Tepikian, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, S.Y. Zhang
BNL, Upton, Long Island, New York, USA
D. Svirida
ITEP, Moscow, Russia

RHIC operation as the polarized proton collider presents unique challenges since both luminosity and spin polarization are important. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system has been installed to improve longitudinal match at injection and to increase luminosity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control has also been improved this year. AGS polarization transfer efficiency is improved by a horizontal tune jump system. To preserve polarization on the ramp, a new working point was chosen with the vertical tune near a third order resonance. The orbit and tune control are essential for polarization preservation. To calibrate the polarization level at 250 GeV, polarized protons were accelerated up to 250GeV and decelerated back to 100GeV. The tune, orbit and chromaticity feedback is essential for this operation. The new record of luminosity was achieved with higher polarization at 250 GeV in this run. The overview of the changes and operation results are presented in this paper.

TUPZ038

RHIC Performance for FY2011 Au+Au Heavy Ion Run

luminosity, cavity, ion, heavy-ion

1894

G.J. Marr, L. A. Ahrens, M. Bai, J. Beebe-Wang, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, C. Carlson, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, W. Fu, C.J. Gardner, D.M. Gassner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, M. Lafky, J.S. Laster, C. Liu, Y. Luo, M. Mapes, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, S. Polizzo, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, C. Schultheiss, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, B. Van Kuik, G. Wang, M. Wilinski, A. Zaltsman, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Following the Fiscal Year (FY) 2010 (Run-10) Relativistic Heavy Ion Collider (RHIC) Au+Au run [1], RHIC experiment upgrades sought to improve detector capabilities. In turn, accelerator improvements were made to improve the luminosity available to the experiments for this run (Run-11). These improvements included: a redesign of the stochastic cooling systems for improved reliability; a relocation of “common” RF cavities to alleviate intensity limits due to beam loading; and an improved usage of feedback systems to control orbit, tune and coupling during energy ramps as well as while colliding at top energy. We present an overview of changes to the Collider and review the performance of the collider with respect to instantaneous and integrated luminosity goals.

WEOAA01

The ThomX Project

laser, injection, cavity, synchrotron

1903

A. Variola
LAL, Orsay, France

Funding: Work supported by the EQUIPEX program, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
ThomX is a Compton source project in the range of the hard X rays (40 / 90 keV). The machine is composed of an injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a Fabry-Perot resonator. The final goal is to provide an X-rays average flux of 1011/10¹³ ph/s. The emitted flux will be characterized by a dedicated X-ray line. Different users are partners in the ThomX project, especially in the area of medical science and cultural heritage. Their main goal will be the transfer of all the experimental techniques developed on big synchrotron rings to these more compact and flexible machines. The project ThomX has recently been funded and will be located on the Orsay University campus. In this article the project and its associated scientific interest are presented.

Slides WEOAA01 [5.947 MB]

WEIB02

Towards Developing Accelerators in Half the Time

controls, alignment, target, background

1978

D.G. Reinertsen
Reinertsen & Associates, Redondo Beach, California, USA

The talk challenges conventional wisdom about how to improve product development processes and broadens the concept of product development cycle time reduction techniques. It provides some original ideas; it discusses approaches to managing product architecture that are well suited for rapid development and how the engineering concepts of system architecture, queuing theory, feedback theory, and information theory can be applied to manage the product development management.

Slides WEIB02 [0.159 MB]

WEPC049

Operation and Storage Ring Calibration with the Transverse Bunch-by-Bunch Feedback System at the Australian Synchrotron

sextupole, damping, synchrotron, storage-ring

2121

M.J. Boland, Y.E. Tan
ASCo, Clayton, Victoria, Australia
D.J. Peake, R.P. Rassool, K.P. Wootton
The University of Melbourne, Melbourne, Australia

The first operational experience with the transverse bunch-by-bunch feedback system for the storage ring shows a doubling of the lifetime and the ability to damp instabilities caused by IVU gap changes. The system was also used to calibrate the ring by doing simultaneous measurements on several single bunches with different bunch currents. Using the bunch-by-bunch system's capability to excite the beam to large amplitudes, the non-linear beam dynamics were also measured and compared with the model.

WEPC091

Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System

extraction, quadrupole, controls, synchrotron

2220

M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker
GSI, Darmstadt, Germany

Several issues concerning the envisaged SIS100 resonant extraction at GSI can be resolved with a simulation-lead approach for which a particle tracking code was developed. Applications to date have included: design and testing of data supply algorithms for the accelerator control system; requirements analysis for the power converter ripple in the quadrupoles forming the doublet focusing; and verification of the RF Knock-Out exciter's performance.

WEPC120

Status of JMAD, the JAVA-API for MADX

optics, controls, status, lattice

2292

K. Fuchsberger, X. Buffat, Y.I. Levinsen, G.J. Müller
CERN, Geneva, Switzerland

MADX (Methodical Accelerator Design) is the de-facto standard software for modeling accelerator lattices at CERN. This feature-rich software package is implemented and still maintained in the programming languages C and FORTRAN. Nevertheless the controls environment of modern accelerators at CERN, e.g., of the LHC, is dominated by JAVA applications. A lot of these applications, for example, for lattice measurement and fitting, require a close interaction with the numerical models, which are all defined by the use of the proprietary MADX scripting language. To close this gap an API to MADX for the JAVA programming language (JMAD) was developed. JMAD was first presented to the public about one year ago. In the meantime, a number of improvements were done, and additional MADX features (e.g., tracking) were made available for JAVA applications. Additionally, the graphical user interface was improved, and the first release as open source software is in reach. This paper describes the current status and some new features of the project, as well as some usage examples.

WEPO036

Design of a Cryogenic Regulation Valve Box for SRF Operation at TPS

SRF, cryogenics, cavity, coupling

2475

M.H. Chang, L.-H. Chang, L.J. Chen, F.-T. Chung, F. Z. Hsiao, M.-C. Lin, Y.-H. Lin, C.H. Lo, H.H. Tsai, Ch. Wang, T.-T. Yang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan
L.L. Han, M.H. Tsai
NTUT, Taiwan

A 3-GeV light source named Taiwan Photon Source (TPS) at National Synchrotron Radiation Research Center (NSRRC) is under construction, and is scheduled for commissioning in 2013/2014. An SRF module of KEKB type has been selected for the TPS as the accelerating cavity of its storage ring. The SRF valve boxes, as part of the cryogenic transfer system, stabilize the cryogenic operational conditions required for various needs of SRF operation. The SRF operation requires a large dynamic variation in the cryogenic loading that challenges appropriate sizing of the cryogenic regulation valves to minimize the pressure drop and concurrently to maintain a fine regulation of pressure. Here, we report our design considerations for an SRF valve box with emphasis on highly stabilizing the helium pressure for SRF operation with a dual-return valve scheme. The estimated fluctuations of pressure due to finite accuracy of the valve opening decrease to a tenth of what is obtained from the conventional single return-valve scheme.

WEPZ007

Multi-mode, Two-beam Accelerator with Feedback

cavity, impedance, accelerating-gradient, RF-structure

2778

S.V. Kuzikov, M.E. Plotkin
IAP/RAS, Nizhny Novgorod, Russia

A high-gradient accelerator consisted of the test and the drive beam structures is reported. The accelerating structure can be based on dielectric or corrugated cavities separated each other by irises. Each cavity is operated by several axisymmetric, TM-like eigen-modes with longitudinal indices to be related to frequencies. These modes are excited at Fourier harmonics of the drive current which consists of bunches spaced with the same period as test bunches. The superposition of the excited modes introduces a short RF pulse propagated in-phase with a moving test bunch and after reflection by iris (a feedback) this pulse can accelerate next bunch. Such longitudinally-sweeping RF field promises a reduction of the exposure time and due to compact space shape can help to obtain high shunt impedance.

THXA01

Recent Trends in Accelerator Control Systems

controls, EPICS, LLRF, coupling

2844

I. Verstovšek, F. Amand, M. Pleško, K. Žagar
Cosylab, Ljubljana, Slovenia

The talk will discuss the approaches of different accelerators, such as FAIR, ESS, MedAustron, XFEL, etc. An overview of different approaches will be given with an emphasis of the recent spectrum of various realizations of accelerator control systems. The talk will not be limited to open source and off-the-shelf software frameworks only but will touch all trends in modern accelerators, including recent trends in hardware. The role of the control system will be highlighted as a common integration framework for various applications, with an emphasis on its increased complexity and scale, and the need for improved reliability and an appropriate service. How control systems can help support the requirements-shaping process early in the project will also be discussed.

Slides THXA01 [1.535 MB]

THOAA02

Implementation of an Intensity Feedback-loop for an Ion-therapy Synchrotron

controls, extraction, ion, synchrotron

2851

C. Schömers, E. Feldmeier, Th. Haberer, J. Naumann, R.E. Panse, A. Peters
HIT, Heidelberg, Germany

The Heidelberg Ion Therapy-Centre (HIT) started treatment of tumour patients in 2009. Its main acceleration stage is a synchrotron, where particles are extracted slowly, in the time frame of some seconds, to support the raster-scanning method. The slow extraction is driven by the transverse "RF-nockout-exciter". So far, this device has a variable but predefined amplitude curve. As the phase-space distribution of particles is not homogeneous and varies slightly from pulse to pulse, intensity-fluctuations of the extracted beam appear. Moreover, changing accelerator-settings requires a time-consuming re-adjustment of the exciter to achieve adequate beam-properties again. To keep the intensity on a predefined level, a feedback loop will be implemented. The actual-value of the intensity is provided by an ionization chamber in front of the patient. The feedback loop controls the amplitude of the Exciter, to adapt the number of extracted particles. Beside a rectangular spill with constant intensity, a dynamic intensity-adaptation during one spill with respect to the particular treatment-plan will be investigated. First tests for flat spill and variable intensity showed promising results.

Slides THOAA02 [2.284 MB]

THPC010

Recent Developments at the Metrology Light Source

quadrupole, injection, synchrotron, vacuum

2927

J. Feikes, T. Birke, O. Dressler, D.B. Engel, F. Falkenstern, B. Franksen, A. Heugel, H.-G. Hoberg, F. Hoffmann, J. Kuszynski, J. Rahn, M. Ries, P.O. Schmid, T. Schneegans, D. Schüler, G. Wüstefeld
HZB, Berlin, Germany
K.B. Bürkmann-Gehrlein, V. Dürr, H.G. Glass, G. Schindhelm
BESSY GmbH, Berlin, Germany
R. Klein
PTB, Berlin, Germany

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, owns the electron storage ring Metrology Light Source (MLS) which was built and is operated by the Helmholtz-Zentrum Berlin [1, 2]. The MLS has been in regular user operation since April 2008 and supports synchrotron-radiation-based metrology and technological developments in the IR, UV, VUV and EUV spectral range. Here we report on recent progress to develop the MLS into a reliable, flexible and stable user facility.

THPC044

Operation and Performance Upgrade of the Soleil Storage Ring

undulator, vacuum, storage-ring, photon

3002

A. Nadji, P. Brunelle, M.-E. Couprie, J.-C. Denard, J.-M. Filhol, J.-F. Lamarre, P. Lebasque, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

SOLEIL delivers photons to 24 beamlines. Up to 22 very diverse insertion devices (IDs) are now installed on the storage ring, and 4 more will come by summer 2011, including a Cryogenic undulator and an electromagnetic/permanent magnet helical undulator, both designed and built at SOLEIL. Work is continuing on beam dynamics and magnetic corrections to reduce the nonlinear effects of all these IDs. A new optics incorporating an additional quadrupole triplet in one long straight section has been successfully tested and will be put in operation by fall 2011. A new coupling correction will also be implemented to maintain the ratio of the vertical to the horizontal emittances at 1% for any IDs configuration. The electron beam orbit stability has been significantly improved reaching a residual noise of 300 nm RMS. Photon LIBERA modules of X-BPM located on the bends, will be integrated soon in the orbit feedback loops. 4905 hours have been delivered in 2010 to the beamlines with an availability of 96.3%. The user operation with the maximum current of 500 mA is foreseen to start by fall 2011, after the completion of the radiation safety tests of the beamlines.

THPC056

Orbit Studies during ALBA Commissioning

coupling, alignment, quadrupole, brilliance

3020

M. Muñoz, G. Benedetti, D. Einfeld, Z. Martí
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The 3rd generation light source ALBA is in the commissioning stage. This paper review the results of the commissioning concerning the transversal beam behavior, in particular the orbit correction system, results from the beam based alignment (BBA), and coupling. The orbit control system of ALBA consists of 88 horizontal and vertical correctors, mounted as extra coils in the sextupole magnets, up to 10⁴ LIBERA BPMs (brilliance version). The correctors magnets would be used for both static orbit correction and for the fast orbit feedback mode, providing up to 1 mrad of correction in the static case. In phase one of the commissioning, the orbit has been corrected down to values of 50 um rms, with an estimated emittance ratio in the order of 1% .

THPO011

Practical Experience with Self-optimizing, High Dynamic Control of Accelerator Magnet Power Supplies

controls, power-supply, proton, resonance

3355

H. Jäckle
PSI, Villigen, Switzerland
F. Jenni, X.H. Ke
FHNW, Windisch, Switzerland

In 1999, the first fully digitally controlled magnet power supplies were commissioned at PSI (Paul Scherrer Institute, Switzerland). Today, approximately 1000 of them are in use at PSI and a multiple of that worldwide. An extended PI structure is used for control. PI control is very effective and simple to use but the attainable dynamic performance is usually limited by the higher order characteristics of the output filter and the load. For the future we expect increasing requirements from highly dynamic applications, such as beam orbit feedback systems and fast scanning magnets for proton irradiation of tumors. Therefore, a self-optimizing power supply control system was developed in collaboration with the University of Applied Sciences Northwestern Switzerland. It is based on the second generation of PSI digital power electronics controller, which allows more complex control algorithms and higher sampling rates. This paper presents the achieved dynamic performance of the new control structure for various types of power supplies and magnets and compares them with the dynamic performance obtained using standard PI control.

THPO014

Analysis and Compensator Design of Magnet Correction Power Supply

controls, power-supply, simulation

3364

Y.S. Wong, J.C. Huang, K.-B. Liu
NSRRC, Hsinchu, Taiwan

This paper presents a new method for the analysis and design of compensators for magnet correction (MC) power supply. The system has to need controllers to satisfy required gain and phase margin specifications and compensator by adding to circuit controller and switch. The gain-phase margin tester method can transform of the controller and find solutions on the figure. According to circuit frequency response and transfer function by theory analysis and simulation design new method compensators to improved anti-disturbance and stability of the system.

THPO017

Improvement of Output Current Characteristics for Bira MCOR30 Correction Magnet Power Supply

controls, power-supply, HOM, storage-ring

3373

J.C. Huang, K.-B. Liu, Y.S. Wong
NSRRC, Hsinchu, Taiwan

The correction magnet power supplies installed at the Taiwan light source (TLS) are Bira Systems’ MCRO 30 power modules, a full-bridge configuration power stage converting the unregulated DC bulk power into a bi-polar current source. The MCOR 30 is theoretically regulated under a very fine control method, with this control method the Bira MCOR 30 should overcome the zero crossover distortion of a standard H-Bridge PWM schemes is used and result in a low frequency noise signature on the output when the magnet current is close to zero. The PWM control circuitry embedded in MCOR 30 theoretically but not really fulfills the purpose what the MCOR 30 want to achieve. With a home-made PWM control circuitry installed into MCOR 30, the width of real pulses can smoothly drop to zero, the MCOR 30 could output current not only with a low frequency noise signature but also much with higher bandwidth of frequency response and much lower Total Harmonic Distortion no matter what output current is demanded.

THPO018

N+1 Redundancy Power Supply System by Paralleling Current Converter Modules with Digital Regulation Control

controls, power-supply, simulation, storage-ring

3376

B.S. Wang, K.-B. Liu, Y.S. Wong
NSRRC, Hsinchu, Taiwan

The N+1 redundancy power supply system is fulfilled with adopting the Bira System MCOR30s as a platform, eight pieces of Bira MCOR 30 power converter boards are installed at crate 2512 and outputs are connected together, the output current of these paralleled eight Bira MCOR 30 power converters are regulated by an external homemade digital control circuit. With homemade digital control circuit, these paralleled eight Bira MCOR 30 power converter modules could deliver up to 240A/30V with ±20ppm precision and stability. The digital regulation control circuit of the N+1 redundancy power supply system is implemented by using a multi-channel DAC5868 16-bits digital-to-analog converter (DAC)、a high speed AD8382 18-bits analog-to-digital converter and a TMS320F28335 digital signal processor (DSP). The update reference voltage frequency of DAC is 83.3 kHz. A DCCT is used as the current feedback component and the output current ripple of the N+1 redundancy power supply system is lower than 20ppm which is beyond the requirement of current TLS quadruple and sextuple power supplies and qualified to be used in the future TPS facility.

THPO019

TPS Fast Corrector Magnet Power Converter

power-supply, booster, controls, monitoring

3379

Y.D. Li, K.-B. Liu
NSRRC, Hsinchu, Taiwan

With the increasing demand of the current output accuracy on the TPS(Taiwan Photon Source) project, the MCOR 30 correction power supplies used in current TLS ring are no longer sufficient to meet the TPS requirement. Therefore, power supply group developments a high-precision low output current power supply with a DCCT as an output current feedback component for correction magnets of the future TPS ring. During the research and development experiment phase, we found the DCCT is more possible damaged than the other components. With keeping the architecture of the high-precision low output current power supply, but the DCCT output current feedback component is replaced with a current sensing Shunt resistor. This paper will discuss the design methods of utilizing several different types current sensing Shunt resistor to reduce the cost of power supply and the probability of damage, and improve frequency response of power supply.

THPO020

TPS Digital Corrector Magnet Power Converter based on FPGA

controls, dipole, booster, quadrupole

3382

Y.D. Li, Y.-C. Chien, K.-B. Liu
NSRRC, Hsinchu, Taiwan

This thesis presents the design and implementation of a FPGA-based fully digital-controlled programmable power supply.

THPS071

The HIMAC Beam-intensity Control System for Heavy-ion Scanning

controls, extraction, status, ion

3592

K. Mizushima
Chiba University, Graduate School of Science and Technology, Chiba, Japan
T. Furukawa, Y. Iwata, K. Katagiri, K. Noda, S. Sato, T. Shirai
NIRS, Chiba-shi, Japan
E. Takeshita
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan

Raster scanning irradiation has been carried out at a HIMAC new treatment facility in NIRS. In order to reduce the difference between prescribed and delivered dose distribution, the accurate beam-intensity control with a low ripple and the fast beam-on/off switching are strongly required. For this purpose, we have developed a new beam-intensity control system using the RF-knockout slow extraction. To keep the beam rate constant, this system controls the transverse RF voltage with the feedback proportional-integral control. In addition, the beam-on/off response was improved by the fast quadrupole magnets and the implementation of the transverse beam preheating method. As a result of the system commissioning, it was verified that this system can modulate the beam-intensity with a low ripple and switch the beam-on/off with quick responses. We will report the result in detail.

THPZ003

The SuperB Project: Accelerator Status and R&D

luminosity, quadrupole, emittance, injection

3684

M.E. Biagini, S. Bini, R. Boni, M. Boscolo, B. Buonomo, T. Demma, E. Di Pasquale, A. Drago, L.G. Foggetta, S. Guiducci, S.M. Liuzzo, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, U. Rotundo, C. Sanelli, M. Serio, A. Stecchi, A. Stella, S. Tomassini, M. Zobov
INFN/LNF, Frascati (Roma), Italy
M.A. Baylac, O. Bourrion, J.-M. De Conto, N. Monseu, C. Vescovi
LPSC, Grenoble, France
K.J. Bertsche, A. Brachmann, Y. Cai, A. Chao, M.H. Donald, R.C. Field, A.S. Fisher, D. Kharakh, A. Krasnykh, K.C. Moffeit, Y. Nosochkov, A. Novokhatski, M.T.F. Pivi, J.T. Seeman, M.K. Sullivan, S.P. Weathersby, A.W. Weidemann, U. Wienands, W. Wittmer, G. Yocky
SLAC, Menlo Park, California, USA
S. Bettoni
PSI, Villigen, Switzerland
A.V. Bogomyagkov, I. Koop, E.B. Levichev, S.A. Nikitin, I.N. Okunev, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin, P. Vobly
BINP SB RAS, Novosibirsk, Russia
B. Bolzon, M. Esposito
CERN, Geneva, Switzerland
F. Bosi
INFN-Pisa, Pisa, Italy
L. Brunetti, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
A. Chancé
CEA, Gif-sur-Yvette, France
P. Fabbricatore, S. Farinon, R. Musenich
INFN Genova, Genova, Italy
E. Paoloni
University of Pisa and INFN, Pisa, Italy
C. Rimbault, A. Variola
LAL, Orsay, France
Y. Zhang
IHEP Beijing, Beijing, People's Republic of China

The SuperB collider project has been recently approved by the Italian Government as part of the National Research Plan. SuperB is a high luminosity (10³6 cm^-2 s^-1) asymmetric e⁺e⁻ collider at the Y(4S) energy. The design is based on a “large Piwinski angle and Crab Waist” scheme already successfully tested at the DAΦNE Phi-Factory in Frascati, Italy. The project combines the challenges of high luminosity colliders and state-of-the-art synchrotron light sources, with two beams (e⁺ at 6.7 and e^- at 4.2 GeV) with extremely low emittances and small beam sizes at the Interaction Point. As unique features, the electron beam will be longitudinally polarized at the IP and the rings will be able to ramp down to collide at the tau/charm energy threshold with one tenth the luminosity. The relatively low beam currents (about 2 A) will allow for low running (power) costs compared to similar machines. The insertion of beam lines for synchrotron radiation users is the latest feature included in the design. The lattice has been recently modified to accommodate insertion devices for X-rays production. A status of the project and a description of R&D in progress will be presented.

THPZ034

Semi-automatic Beam-based Alignment Algorithm for the LHC Collimation System

alignment, controls, collimation, beam-losses

3768

G. Valentino, R.W. Assmann, S. Redaelli, N.J. Sammut, D. Wollmann
CERN, Geneva, Switzerland
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Full beam-based alignment of the LHC collimation system was a lengthy procedure as the collimators were set up manually. A yearly alignment campaign has been sufficient for now, although in future this may lead to a decrease in the cleaning efficiency if machine parameters such as the beam orbit drift over time. Automating the collimator setup procedure can allow for more frequent alignments, therefore reducing this risk. This paper describes the design and testing of a semi-automatic algorithm as a first step towards a fully automatic setup. Its implementation in the collimator control software and future plans are described.

FRXCA01

First Years Experience of LHC Beam Instrumentation

emittance, beam-losses, instrumentation, luminosity

3779

O.R. Jones
CERN, Geneva, Switzerland

The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. This talk will comment on all of these systems and on their contributions to the various stages of beam commissioning. It will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; synchrotron light diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

Slides FRXCA01 [7.322 MB]