IPAC2011 - List of Keywords (pick-up)

Paper	Title	Other Keywords	Page
MOPC045	Commissioning of the ALBA Storage Ring RF System	cavity, LLRF, storage-ring, HOM	178
	F. Pérez, B. Bravo, A. Salom, P. Sanchez CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3 GeV, 400 mA, 3rd generation Synchrotron Light Source that is under commissioning in Cerdanyola, Spain. The RF System has to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. For that six RF plants, working at 500 MHz, are foreseen. The RF plants include several new developments: DAMPY cavity; the normal conducting HOM damped cavity developed by BESSY and based in the EU design; six are installed. CaCo; a cavity combiner to add the power of two 80 kW IOTs to produce the 160 kW needed for each cavity. WATRAX; a waveguide transition to coaxial, specially designed to feed the DAMPY cavities due to the geometrical and cooling constrains. Digital LLRF; fully designed at ALBA using commercial components. This paper shortly describes these systems and reports their performance during the ALBA commissioning.

MOPC052	Engineering Design and Fabrication of X-band RF Components	vacuum, klystron, coupling, diagnostics	196
	M. Filippova, A. Olyunin, V. Soldatov, A. Solodko JINR, Dubna, Moscow Region, Russia S. Atieh, G. Riddone, I. Syratchev CERN, Geneva, Switzerland
	The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for accelerating structure testing. X-band klystron test facilities at 11.424 GHz are operated at SLAC and at KEK, and these facilities are used by CLIC study in the frame of the X-band structure collaboration for testing accelerating structures scaled to that frequency. Generally RF components are used in the transmission and the transformation of radio frequency signals generated by the power supply. The operating range of the devices accommodates the frequencies from 11.424 to 11.9942 GHz. RF components are needed for the Klystron test stand at CERN, and also for the X-FEL projects at PSI and Sincrotrone Trieste. Currently CERN is ordering tens of these companies to industry. The engineering design of the RF components (high power and compact loads, bi-directional couplers, X-band splitters, hybrids, phase shifters, variable power attenuators) and the main fabrication processes are presented here. K.M. Schirm et al., “A 12 GHZ RV Power source for the CLIC study”, Proc. of IPAC’10, THPEB053, p. 3990 (2010).

MOPC055	High Power Test of the First PIMS Cavity for Linac4	cavity, linac, vacuum, klystron	205
	F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner CERN, Geneva, Switzerland
	The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC148	Optical Clock Distribution System at the ALICE Energy Recovery Linac	laser, electron, FEL, feedback	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.

MOPC152	Digital Control System for Solid State Direct Drive™ RF-Linacs	controls, cavity, LLRF, linac	436
	J. Sirtl, M. Back, T. Kluge Siemens AG, Erlangen, Germany H. Schröder ASTRUM IT GmbH, Erlangen, Germany
	The Solid State Direct Drive™ concept for RF linacs has previously been introduced. Due to the different methodology (i.e. solid state based rather than electron tube based) as compared with conventional RF sources a new control system is required to deliver the required LLRF. To support this new technology a fully digital control system for this new concept has been developed. Progresses in Digital – Analogue Converter technology and FPGA technology allows us to create a digital System which works in the 150 Mhz baseband. The complete functionality was implemented in a Virtex 6 FPGA. Dispensing with the PLL allows an excellent jitter-behaviour. For this job, we use three 12 bit ADCs with a Sampling Rate of 1 GS/s and two 16 bit DACs (1 GS/s). The amplitude of the RF source is controlled by dividing the RF modules mounted on the power combiner* into two groups and controlling the relative phase of each group (in effect mimicking an “out-phasing” amplifier). This allows the modules to be operated at their optimum working point and allows a linear amplitude behaviour. * O. Heid, T. Hughes, Proc. of IPAC10, THPD002, p. 4278, Kyoto, Japan (2010). ** O. Heid, T. Hughes, Proc. of LINAC10, THPD068, Tsukuba, Japan.

MOPO005	A Transverse Feedback System using Multiple Pickups for Noise Minimization	kicker, synchrotron, feedback, 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.

MOPO013	Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment	feedback, 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.

MOPO037	Concept of Femtosecond Timing and Synchronization Scheme at ELBE	laser, electron, controls, status	565
	M. Kuntzsch, A. Büchner, M. Gensch, A. Jochmann, T. Kirschke, U. Lehnert, F. Röser HZDR, Dresden, Germany M.K. Bock, M. Bousonville, M. Felber, T. Lamb, H. Schlarb, S. Schulz DESY, Hamburg, Germany
	The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf is undergoing an extension to offer capacity for various applications. The extension includes the setup of a THz-beamline with a dedicated laboratory and a beamline for electron-beam - high-power laser interaction. The current synchronization scheme offers stability on the picoseconds level. For pump-probe experiments using optical lasers, the desired synchronization between the pump and the probe pulse should be on the femtosecond scale. In the future there will be an optical synchronization system with a pulsed fiber laser as an optical reference. The laser pulses will be distributed over stabilized fiber links to the remote stations. It is planned to install EOM-based beam arrival time monitors (BAMs) in order to monitor the bunch jitter and to establish a beam-based feedback to reduce the jitter. Besides that, the timing system has to be revised to generate triggers for experiments with low repetition rate, two electron guns (thermionic DC, superconducting RF) and several lasers. The Poster will show the possible layout of the future Timing and Synchronization System at ELBE.

MOPZ011	An Automated Conditioning System for the MUCOOL Experiments at Fermilab	cavity, controls, vacuum, collider	844
	A. Kurup Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The MUCOOL project aims to study RF cavities for the Neutrino Factory and the Muon Collider. The large emittance muon beams in these accelerators require high-gradient RF cavities at low-frequencies and they need to operate in the presence of relatively strong magnetic fields. MUCOOL is conducting a number of tests on 805MHz and 201 MHz cavities in order to develop a technology that can meet all of these requirements. An automated conditioning system was developed for the 805MHz test program for MUCOOL. This system was designed to replicate the logic a human operator would use when conditioning an RF cavity and to provide automated logging of the conditioning process. This paper describes the hardware and software of the system developed.

TUYA03	Stochastic Cooling of a High Energy Collider	simulation, kicker, cavity, luminosity	913
	M. Blaskiewicz, J.M. Brennan, R.C. Lee, K. Mernick BNL, Upton, Long Island, New York, USA
	Three dimensional stochastic cooling was successfully implemented at the Relativistic Heavy Ion Collider to overcome emittance growth from intra-beam scattering. The talk reports on the experience of operating a collider with continuous cooling. The application of such techniques to other hadron machine (e.g. LHC) will be discussed.
	Slides TUYA03 [1.350 MB]

TUPC007	Kicker and Monitor for CTF3 Phase Feed Forward	kicker, impedance, coupling, collider	1000
	F. Marcellini, D. Alesini, A. Ghigo INFN/LNF, Frascati (Roma), Italy
	Funding: Work partially supported by the EuCARD research programme, Grant Agreement 227579, within the 'Assessment of Novel Accelerator Concepts'. In the Compact LInear Collider (CLIC) the synchronization of the Drive Beam and the Main Beam has to be assured in the femtosecond range to avoid luminosity reduction of the collider. The Drive and Main Beams arrival time is measured with longitudinal monitors and the correction is applied changing the path length of one beam respect to the other in a magnetic chicane by means of two transverse fast stripline kicker. The performance of the feed forward system will be tested in the CLIC Test Facility (CTF3) measuring the phase at the linac exit, correcting in the chicane after the combination rings and comparing the longitudinal position change before the power RF production system. The developed phase monitors and kicker magnets for the test in CTF3 are described.

TUPC033	Verifying the Single Bunch Capability of the New Injector at ELSA*	linac, electron, gun, single-bunch	1072
	S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler ELSA, Bonn, Germany S. Aderhold DESY, Hamburg, Germany
	Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale". In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.

TUPC076	Realization of a High Bandwidth Bunch Arrival-time Monitor with Cone-shaped Pickup Electrodes for FLASH and XFEL	electron, laser, coupling, free-electron-laser	1177
	A. Angelovski, M. Hansli, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M. Bousonville, H. Schlarb DESY, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA In the Free Electron Laser in Hamburg (FLASH) an electro-optical system is used as a Bunch Arrival time Monitor (BAM). The time-of-arrival resolution is proportional to the steepness of the beam pick-up signal at the first zero-crossing. Future experiments will be conducted using significantly lower bunch charges resulting in a reduced signal steepness. This requires BAM pickup electrodes with increased bandwidth as introduced in . This paper presents the implementation and measurement results of a high bandwidth cone-shaped pickup capable of operating in the frequency range up to 40 GHz. The slope steepness at the zero crossing is investigated for a simplified equivalent circuit model. RF-measurements have been performed using a non-hermetic prototype of the BAM pickups for assessing the influence of manufacturing tolerances on the sensor performance. The measurements are compared to simulation results obtained by CST PARTICLE STUDIO®. F. Loehl et al., Proc. of DIPAC2007, WEPB15, p. 262 (2007). ** A. Angelovski et al., "Pickup design for a high resolution Bunch Arrival time Monitor for FLASH and XFEL", DIPAC2011.

TUPC079	Sensitivity and Tolerance Analysis of a New Bunch Arrival-time Monitor Pickup Design for FLASH and XFEL	simulation, laser, electron, free-electron-laser	1186
	A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M. Bousonville, H. Schlarb DESY, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Supported by the Graduate School of Computational Engineering at TU Darmstadt and the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free Electron Laser in Hamburg (FLASH) is equipped with Bunch Arrival Time Monitors (BAM), which provide for a time resolution of less than 10 fs for bunch charges higher than 0.2 nC. Future experiments, however, will aim at generating FEL light pulses from a broad range of bunch charges down to 10 pC. In these circumstances the requirements on the time resolution will no longer be fulfilled, which demands for a larger bandwidth of the pickup system. A new cone-shaped pickup, which has a bandwidth greater than 40 GHz has been proposed. At high frequencies, small manufacturing tolerances might have great influence on the pickup signal. A sensitivity analysis of several manufacturing tolerances in the pickup design regarding their influence on the output signal was carried out (by means of CST PARTICLE STUDIO®). These results are utilized for setting limits to the manufacturing tolerances. M.K. Bock et al., IPAC2010, WEOCMH02, Kyoto, Japan, 2010. ** A. Kuhl et al., "Design eines hochauflösenden Ankunftszeitmonitor für FLASH", DPG Frühjahrstagung 2011, Karlsruhe, Germany.

TUPC080	Pickup Design with Beta Matching	impedance, simulation, resonance, kicker	1189
	J.A. Tsemo Kamga, W.F.O. Müller, K.K. Stavrakakis, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by GSI The main goal of this project is to investigate the Schottky noise of an ion beam in the frequency range from 3 to 5 GHz. In order to accomplish this task, a pickup design is required. For an efficient study of this Schottky noise the pickup sensitivity for low beta must be increased. A design for such a problem has been developed by McGinnis for a fixed beam velocity but can also be used for variable beta by using a tunable material (ferroelectric) inside the waveguide. Since such tunable materials like for instance BST (Barium Strontium Titanate) are lossy, the impact of dielectric losses on the pickup sensitivity will also be investigated in this work. Additionally to the classical parameter studies where multiple simulation runs based on the original numerical model are initiated to characterize the various design parameters it is also possible to utilize a reduced model instead. In particular one is interested in a fast evaluation of the frequency response while taking also material variations into account. In this work, a multivariate parameterized dynamical system is set up and used complementary to the full model for the required beam characterization.

TUPC082	Beam Current Measurements at the TSR Heidelberg	ion, acceleration, electron, storage-ring	1195
	M. Grieser, S.T. Artikova, K. Blaum, F. Laux, J. Ullrich MPI-K, Heidelberg, Germany
	To conduct experiments using low energy ion beams at the TSR heavy ion storage ring, the beam deceleration process must be well understood. During deceleration of the beam the revolution frequency decreases, resulting in low current, which is difficult to measure with a common DC transformer. The number of particles in a bunch is determined by measuring the voltage signal in the time domain using a capacitive pick-up. If the ratio of bunch length and RF period does not change during the deceleration or acceleration, measuring the pick-up signal spectrum, where the signal is directly proportional to the number of particles in a bunch, is a more sensitive method. An alternative method is using a beam profile monitor (BPM) for determining the number of particles in the storage ring via ionization rate measurements of the residual gas. A summary of these different methods to determine the number of particles is presented.

TUPC115	Application of Libera Brilliance Single Pass at NSRL Linac BPM System	brilliance, linac, controls, injection	1284
	J.Y. Zou, J. Fang, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Libera Brilliance Single Pass is a digital beam position processor with capabilities of single pass position measurement. This device can be used on the stripline beam position monitor (BPM) of the linac and transfer lines on light sources as well as injector system for the FELs. The linac of Hefei light source (HLS) was equipped with 2 stripline beam position monitors, which will be increased to 20 BPMs after upgrading. The existing BPM electronics were the homemade electronics with logarithm detector. To enhance the functionality of the BPM system, the Libera Brilliance Single Pass is employed to replace the existing BPM electronics. The newly buying devices have made test of characterization. The mapping of stripline BPM is made on a workbench with Libera Brilliance Single Pass. The beam position is tested at linac using Libera Brilliance Single Pass. And the results of these measurement performed on Libera are reported to compared to measurements with the linac’s existing BPM electronics.

TUPC125	Test of the Front-end Electronics and Acquisition System for the LIPAC BPMs	EPICS, controls, linac, LLRF	1311
	D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo ESS-Bilbao, Zamudio, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, I. Podadera CIEMAT, Madrid, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain N. Garmendia, L. Muguira ESS Bilbao, Bilbao, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230. Non-interceptive Beam Position Monitors pickups (BPMs) will be installed along the beamlines of the IFMIF/EVEDA linear prototype accelerator (LIPAC) to measure the transverse beam position in the vacuum chamber in order to correct the dipolar and tilt errors. Depending on the location, the BPMs response must be optimized for a beam of 175 MHz bunch repetition, an energy range from 5 up to 9 MeV, a current between 0.1 and 125 mA and continuous and pulse operation. The requirements from beam dynamics for the BPMs are quite stringent, aiming for the position an accuracy below 100 μm and a resolution below 10 μm, and for the phase an accuracy below 2° and a resolution below 0.3°. To meet these specifications, the BPM electronics system developed by ESS-Bilbao has been adapted for its use with the BPMs of LIPAC. This electronics system is divided in an Analog Front-End unit, where the signals are conditioned and converted to baseband, and a Digital Unit to sample them and calculate the position and phase. The electronics system has been tested at CIEMAT with a wire test bench and a prototype BPM. In this contribution, the tests performed will be fully described and the results discussed.

TUPC130	Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN	quadrupole, monitoring, linac, beam-transport	1326
	J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe IFIC, Valencia, Spain S. Döbert CERN, Geneva, Switzerland
	Funding: Funding Agency: FPA2010-21456-C02-01 A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC134	Phase Detection Electronics for CLIC	controls, linac, luminosity, linear-collider	1338
	A. Andersson CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) requires very tight RF phase synchronisation in order to preserve high luminosity. The electronics required for processing the signals delivered from the phase pick-ups present a significant challenge. This paper discusses the strategy adopted to achieve a sufficiently accurate measurement of the phase. Performance measurements performed in the lab of some of the sub-systems are also presented.

TUPC155	Optimisation of the LHC Beam Current Transformers for Accurate Luminosity Determination	luminosity, instrumentation, monitoring, synchrotron	1395
	J-J. Gras, D. Belohrad, M. Ludwig, P. Odier CERN, Geneva, Switzerland C. Barschel RWTH, Aachen, Germany
	During the 2010 and 2011 LHC runs a series of dedicated fills were used for luminosity calibration measurements at each of the LHC experiments. A major contribution to the final precision of these luminosity calibration campaigns originated from the absolute accuracy of the bunch current population estimation. The importance of these measurements for the LHC physics community triggered a large and fruitful collaboration between the CERN Beam Instrumentation Group and the LHC Experiments to push the LHC Beam Current Transformers performance to their limit. This paper will report on the available instruments for beam current measurements, the methodology used to improve them and the results obtained.

TUPC163	Experimental Results from Test Measurements with the USR Beam Position Monitoring System	simulation, storage-ring, vacuum, alignment	1416
	J. Harasimowicz, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Harasimowicz, I. Takov The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328. A diagonal-cut capacitive pick-up (PU) was optimised for monitoring slow (v < 0.025c), long (~1 m) bunches consisting of only about 10⁶ antiprotons at the future Ultra-low energy Storage Ring (USR). Ultra-low noise (0.5 nV/Hz⁰.5) FET pre-amplifiers are used to allow detection of the weak signals generated in the PU plates. The amplified signals are then digitized by a 16-bit, 200 MS/s ADC and processed in a digital manner. The following contribution presents the beam monitoring system as it was tested with a stretched-wire method and compares the measurements with the results from 3D electromagnetic simulations.

TUPC172	Evaluation and Correction of the Non-linear Distortion of CEBAF Beam Position Monitors	electron, simulation, radiation	1440
	M. Spata, T.L. Allison, K.E. Cole, J. Musson, J. Yan JLAB, Newport News, Virginia, USA
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The beam position monitors at CEBAF have four antenna style pickups that are used to measure the location of the beam. There is a strong nonlinear response when the beam is far from the electrical center of the device. In order to conduct beam experiments at large orbit excitation we need to correct for this nonlinearity. The correction algorithm is presented and compared to measurements from our stretched wire BPM test stand.

TUPS035	LHC Collimators with Embedded Beam Position Monitors: A New Advanced Mechanical Design	alignment, collimation, simulation, radiation	1611
	A. Dallocchio, A. Bertarelli, C.B. Boccard, F. Carra, M. Gasior, L. Gentini, M.A. Timmins CERN, Geneva, Switzerland
	The LHC collimation system, ensuring both functions of beam cleaning and machine protection, is potentially submitted to high-energy beam impacts. Currently the collimators setup is performed by monitoring beam losses generated by the collimator jaws when approaching the particle beam. This procedure is applied to all LHC collimators (almost one hundred), taking several hours, and needs to be repeated if beam settings change significantly. Furthermore, during the beam-based alignment, the LHC tertiary collimators are potentially exposed to abnormal losses entailing possible damage to their tungsten jaws. To improve the efficiency of the machine operation and better control the particle beam a new advanced design embedding Beam Position Monitors (BPM) into the movable collimator jaws has been developed. This paper describes the mechanical design of various types of future collimators with embedded BPMs. Experimental measurements performed on a simplified functional prototype installed in the CERN SPS showed that, thanks to on-board BPMs, the collimator could be precisely, rapidly, and safely aligned and the beam position accurately measured.

TUPS093	Automatic Measurement System for Electrical Verification of the LHC Superconducting Circuits	high-voltage, instrumentation, superconducting-magnet, dipole	1756
	A. Kotarba, M. Bednarek, P. Jurkiewicz, J. Ludwin, M. Talach IFJ-PAN, Kraków, Poland R. Mompo CERN, Geneva, Switzerland
	In the LHC machine, superconducting magnet circuits are used on a very large scale. The circuits, more than 1600, are all equipped with a complex set of instrumentation required for safe operation and diagnostics. The length of many circuits exceed 3 km. Due to risks of accidental damages during transport and assembly or misconnection of the circuits’ auxiliary components, it is necessary to perform an Electrical Quality Assurance (ELQA) campaign after every major intervention on a circuit and also after each thermal cycle of the machine. In order to be able to perform reliable tests on a circuit within a short time frame, a highly extensible automated mobile test system was designed and built. Four of these instruments were successfully used during the Hardware Commissioning phases of the LHC. This paper describes the hardware solutions used in the test system.

TUPZ022	Longitudinal Beam Measurements at the LHC: The LHC Beam Quality Monitor	injection, controls, emittance, damping	1852
	G. Papotti, T. Bohl, F. Follin, U. Wehrle CERN, Geneva, Switzerland
	The LHC Beam Quality Monitor is a system that measures individual bunch lengths and positions, similarly to the twin system SPS Beam Quality Monitor, from which it was derived. The pattern verification that the system provides is vital during the injection process to verify the correctness of the injected pattern, while the bunch length measurement is fedback to control the longitudinal emittance blow up performed during the energy ramp. In 2010 the system could for example clearly detect instances of longitudinal instabilities and beam excitation due to excess RF noise. The algorithms used, the hardware implementation and the system integration in the LHC control infrastructure are presented in this paper, along with possible improvements.

WEPC123	Numerical Algorithm based on the PDE Method for the Solution of the Fokker-Planck Equation	simulation, kicker, storage-ring, impedance	2298
	M. Dolinska NASU/INR, Kiev, Ukraine C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt, Germany
	Funding: Work supported by HIC for FAIR This paper discus a fast and accurate algorithm for numerical solution of Fokker-Planck equation based on the solution of the parabolic Partial Differential Equations (PDE), where the Crank–Nicholson scheme is used. The stability, convergence and round-off errors of the algorithm are studied. The numerical results on Fokker–Planck equation solution with PDE method are compared with other numerical methods. Using the PDE solver, we will be able to predict the stochastic cooling process of notch filter in storage rings.

WEPC135	Recent Developments in Modeling Time-resolved Shielded-pickup Measurements of Electron Cloud Buildup at CESRTA	vacuum, electron, radiation, photon	2313
	J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, J.P. Sikora CLASSE, Ithaca, New York, USA R.P. Badman Syracuse University, Syracuse, USA S. Calatroni, G. Rumolo CERN, Geneva, Switzerland S. Kato KEK, Ibaraki, Japan
	Funding: Work supported by the U.S. National Science Foundation PHY-0734867, PHY-1002467 and the U.S. Department of Energy DE-FC02-08ER41538 The Cornell Electron Storage Ring Test Accelerator program includes investigations into the mitigation of electron cloud buildup using a variety of techniques in custom vacuum chambers. The CESR ring accommodates two such chambers equipped with BPM-style pickup detectors shielded against the direct beam-induced signal. The signals provide time-resolved information on cloud development. Results for diamond-like carbon, amorphous carbon, and TiN coatings have been compared to those for an uncoated aluminum chamber. Here we report on extensions to the ECLOUD modeling code which refine its description of a variety of new types of in situ vacuum chamber comparisons. Our results highlight the sensitivity afforded by these measurements to the modeled photoelectron production and secondary yield parameters. We draw conclusions comparing the photoelectron and secondary yield properties of the various vacuum chamber coatings, including conditioning effects as a function of synchrotron radiation dose. We find substantial conditioning effects in both the quantum efficiency for producing photoelectrons and in the secondary yield.

WEPC145	Progress in Developing a PLC Control System for the PKUNIFTY	controls, rfq, cavity, neutron	2331
	J. Zhao, J.E. Chen, Z.Y. Guo, Y.R. Lu, S.X. Peng, Q.F. Zhou PKU/IHIP, Beijing, People's Republic of China
	A compact remote PLC control system has been developed for the PKUNIFTY (Peking University Neutron Imaging FaciliTY). That facility is based on a 2 MeV deuteron RFQ accelerator. The PLC control system has been successfully used for the injector including ECR ion source and LEBT, and it worked reliably last year. Now the control of RFQ cavity, HEBT and Be target has been completed and tested. The interlock system has been enhanced. A low level RF control system, including the auto frequency control (AFC) and auto gain control (AGC) circuits, has been designed for the RFQ’s RF power system. Those circuits will work as a lower controller of the PLC control system. The main running parameters can be controlled by setting any desired range of values on the HMI. Test results of hardware and software are presented.

WEPC158	The EMMA Accelerator, A Diagnostic Systems Overview	injection, extraction, diagnostics, EPICS	2355
	R.J. Smith, M. Dufau, C. Hill, J.K. Jones, A. Kalinin, L. Ma, P.A. McIntosh, B.D. Muratori, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.S. Berg BNL, Upton, Long Island, New York, USA N. Bliss, G. Cox, A. Gallagher, A. Oates STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom R.G. Borrell WareWorks Ltd, Manchester, United Kingdom J.L. Crisp FRIB, East Lansing, Michigan, USA K.M. Hock, D.J. Holder Cockcroft Institute, Warrington, Cheshire, United Kingdom M.G. Ibison, I. Kirkman The University of Liverpool, Liverpool, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The ‘EMMA’ Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) international project is currently being commissioned at Daresbury Laboratory, UK. This accelerator has been equipped with a number of diagnostic systems to facilitate this. These systems include a novel time-domain-multiplexing BPM system, moveable screen systems, a time-of-flight instrument, Faraday cups, and injection/extraction tomography sections to analyse the single bunch beams. An upgrade still to implement includes the installation of a fast wall current monitor. This paper gives an overview of these systems and shows some data and results that have contributed to the successful demonstration of a serpentine acceleration by this novel accelerator.

WEPS007	CNAO Synchrotron Commissioning	synchrotron, extraction, proton, betatron	2496
	C. Priano, G. Balbinot, G. Bazzano, J. Bosser, E. Bressi, M. Caldara, H. Caracciolo, L. Falbo, A. Parravicini, M. Pullia, C. Viviani CNAO Foundation, Milan, Italy C. Biscari, A. Ghigo INFN/LNF, Frascati (Roma), Italy
	The CNAO (National Center for Oncological Hadrontherapy), located in Pavia, is the first Italian center for deep hadrontherapy with proton and carbon ion beams. The CNAO synchrotron initial commissioning has been carried out using proton beams in the full range of energies: 60 to 250 MeV/u. The first foreseen treatments will need energies between 120 and 170 MeV/u. The nominal proton currents have been reached. The energy scaling of the synchrotron systems and parameters leads to an extracted energy that matches the measured particle range better than 0.1 mm, fitting the treatment requirements, with repeatable beam size and beam current in the treatment room at all investigated energies. A summary of the main results of the synchrotron commissioning is presented.

WEPS041	Tuning of the New 4-Rod RFQ for FNAL	rfq, resonance, simulation, linac	2580
	J.S. Schmidt, B. Koubek, A. Schempp IAP, Frankfurt am Main, Germany
	For the injector upgrade at FNAL a 4-rod Radio Frequency Quadrupole (RFQ) with a resonance frequency of 200 MHz has been build. With this short structure of only 1.3 m a very compact injector design has been realized. Simulations with CST Microwave Studio® were performed for the design. Their results leading to the RF characterizations of the RFQ and the final RF setup which has been accomplished at IAP of the Goethe-University Frankfurt are presented in this paper.

THPO006	A Digital Power Supply Control Model in Heavy-ion Accelerator based on Dual Nios Cores	power-supply, controls, ion, heavy-ion	3346
	R.K. Wang, Y.X. Chen, D.Q. Gao, Y.Z. Huang, H.B. Yan, H.H. Yan, Z.Z. Zhou IMP, Lanzhou, People's Republic of China R.K. Wang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	According to the features of digital power supply and the requirements of pulse mode,this paper introduces a Digital Power Supply Control Mode(DPSCM) in Heavy-Ion Accelerator based on dual Nios cores,which meets the requirements of two basic running modes. The new method develops a system on-chip based on dual Nios cores by using SOPC technology in the Altera EP2C70 FPGA. Compared with traditional DPSCM,the dual Nios cores run simultaneously and cooperate well. As a result,the efficiency of the system is remarkably improved. Further,cores in parallel can realize reference waveforms switch in pulse mode effectively. We choose a 1150A/185V power supply as test bench. The Experimental result indicates that the system can realize the function of pulse mode,and the stability and tracking error meet the design requirements.

THPS003	Status of Stochastic Cooling Predictions at the HESR	antiproton, accumulation, kicker, injection	3430
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany T. Katayama GSI, Darmstadt, Germany
	Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.

Paper

Title

Other Keywords

Page

MOPC045

Commissioning of the ALBA Storage Ring RF System

cavity, LLRF, storage-ring, HOM

178

F. Pérez, B. Bravo, A. Salom, P. Sanchez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a 3 GeV, 400 mA, 3rd generation Synchrotron Light Source that is under commissioning in Cerdanyola, Spain. The RF System has to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. For that six RF plants, working at 500 MHz, are foreseen. The RF plants include several new developments: DAMPY cavity; the normal conducting HOM damped cavity developed by BESSY and based in the EU design; six are installed. CaCo; a cavity combiner to add the power of two 80 kW IOTs to produce the 160 kW needed for each cavity. WATRAX; a waveguide transition to coaxial, specially designed to feed the DAMPY cavities due to the geometrical and cooling constrains. Digital LLRF; fully designed at ALBA using commercial components. This paper shortly describes these systems and reports their performance during the ALBA commissioning.

MOPC052

Engineering Design and Fabrication of X-band RF Components

vacuum, klystron, coupling, diagnostics

196

M. Filippova, A. Olyunin, V. Soldatov, A. Solodko
JINR, Dubna, Moscow Region, Russia
S. Atieh, G. Riddone, I. Syratchev
CERN, Geneva, Switzerland

The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for accelerating structure testing. X-band klystron test facilities at 11.424 GHz are operated at SLAC and at KEK, and these facilities are used by CLIC study in the frame of the X-band structure collaboration for testing accelerating structures scaled to that frequency*. Generally RF components are used in the transmission and the transformation of radio frequency signals generated by the power supply. The operating range of the devices accommodates the frequencies from 11.424 to 11.9942 GHz. RF components are needed for the Klystron test stand at CERN, and also for the X-FEL projects at PSI and Sincrotrone Trieste. Currently CERN is ordering tens of these companies to industry. The engineering design of the RF components (high power and compact loads, bi-directional couplers, X-band splitters, hybrids, phase shifters, variable power attenuators) and the main fabrication processes are presented here.
* K.M. Schirm et al., “A 12 GHZ RV Power source for the CLIC study”, Proc. of IPAC’10, THPEB053, p. 3990 (2010).

MOPC055

High Power Test of the First PIMS Cavity for Linac4

cavity, linac, vacuum, klystron

205

F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner
CERN, Geneva, Switzerland

The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC148

Optical Clock Distribution System at the ALICE Energy Recovery Linac

laser, electron, FEL, feedback

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.

MOPC152

Digital Control System for Solid State Direct Drive™ RF-Linacs

controls, cavity, LLRF, linac

436

J. Sirtl, M. Back, T. Kluge
Siemens AG, Erlangen, Germany
H. Schröder
ASTRUM IT GmbH, Erlangen, Germany

The Solid State Direct Drive™ concept for RF linacs has previously been introduced*. Due to the different methodology (i.e. solid state based rather than electron tube based) as compared with conventional RF sources a new control system is required to deliver the required LLRF. To support this new technology a fully digital control system for this new concept has been developed. Progresses in Digital – Analogue Converter technology and FPGA technology allows us to create a digital System which works in the 150 Mhz baseband. The complete functionality was implemented in a Virtex 6 FPGA. Dispensing with the PLL allows an excellent jitter-behaviour. For this job, we use three 12 bit ADCs with a Sampling Rate of 1 GS/s and two 16 bit DACs (1 GS/s). The amplitude of the RF source is controlled by dividing the RF modules mounted on the power combiner** into two groups and controlling the relative phase of each group (in effect mimicking an “out-phasing” amplifier). This allows the modules to be operated at their optimum working point and allows a linear amplitude behaviour.
* O. Heid, T. Hughes, Proc. of IPAC10, THPD002, p. 4278, Kyoto, Japan (2010).
** O. Heid, T. Hughes, Proc. of LINAC10, THPD068, Tsukuba, Japan.

MOPO005

A Transverse Feedback System using Multiple Pickups for Noise Minimization

kicker, synchrotron, feedback, 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.

MOPO013

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

feedback, 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.

MOPO037

Concept of Femtosecond Timing and Synchronization Scheme at ELBE

laser, electron, controls, status

565

M. Kuntzsch, A. Büchner, M. Gensch, A. Jochmann, T. Kirschke, U. Lehnert, F. Röser
HZDR, Dresden, Germany
M.K. Bock, M. Bousonville, M. Felber, T. Lamb, H. Schlarb, S. Schulz
DESY, Hamburg, Germany

The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf is undergoing an extension to offer capacity for various applications. The extension includes the setup of a THz-beamline with a dedicated laboratory and a beamline for electron-beam - high-power laser interaction. The current synchronization scheme offers stability on the picoseconds level. For pump-probe experiments using optical lasers, the desired synchronization between the pump and the probe pulse should be on the femtosecond scale. In the future there will be an optical synchronization system with a pulsed fiber laser as an optical reference. The laser pulses will be distributed over stabilized fiber links to the remote stations. It is planned to install EOM-based beam arrival time monitors (BAMs) in order to monitor the bunch jitter and to establish a beam-based feedback to reduce the jitter. Besides that, the timing system has to be revised to generate triggers for experiments with low repetition rate, two electron guns (thermionic DC, superconducting RF) and several lasers. The Poster will show the possible layout of the future Timing and Synchronization System at ELBE.

MOPZ011

An Automated Conditioning System for the MUCOOL Experiments at Fermilab

cavity, controls, vacuum, collider

844

A. Kurup
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The MUCOOL project aims to study RF cavities for the Neutrino Factory and the Muon Collider. The large emittance muon beams in these accelerators require high-gradient RF cavities at low-frequencies and they need to operate in the presence of relatively strong magnetic fields. MUCOOL is conducting a number of tests on 805MHz and 201 MHz cavities in order to develop a technology that can meet all of these requirements. An automated conditioning system was developed for the 805MHz test program for MUCOOL. This system was designed to replicate the logic a human operator would use when conditioning an RF cavity and to provide automated logging of the conditioning process. This paper describes the hardware and software of the system developed.

TUYA03

Stochastic Cooling of a High Energy Collider

simulation, kicker, cavity, luminosity

913

M. Blaskiewicz, J.M. Brennan, R.C. Lee, K. Mernick
BNL, Upton, Long Island, New York, USA

Three dimensional stochastic cooling was successfully implemented at the Relativistic Heavy Ion Collider to overcome emittance growth from intra-beam scattering. The talk reports on the experience of operating a collider with continuous cooling. The application of such techniques to other hadron machine (e.g. LHC) will be discussed.

Slides TUYA03 [1.350 MB]

TUPC007

Kicker and Monitor for CTF3 Phase Feed Forward

kicker, impedance, coupling, collider

1000

F. Marcellini, D. Alesini, A. Ghigo
INFN/LNF, Frascati (Roma), Italy

Funding: Work partially supported by the EuCARD research programme, Grant Agreement 227579, within the 'Assessment of Novel Accelerator Concepts'.
In the Compact LInear Collider (CLIC) the synchronization of the Drive Beam and the Main Beam has to be assured in the femtosecond range to avoid luminosity reduction of the collider. The Drive and Main Beams arrival time is measured with longitudinal monitors and the correction is applied changing the path length of one beam respect to the other in a magnetic chicane by means of two transverse fast stripline kicker. The performance of the feed forward system will be tested in the CLIC Test Facility (CTF3) measuring the phase at the linac exit, correcting in the chicane after the combination rings and comparing the longitudinal position change before the power RF production system. The developed phase monitors and kicker magnets for the test in CTF3 are described.

TUPC033

Verifying the Single Bunch Capability of the New Injector at ELSA*

linac, electron, gun, single-bunch

1072

S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler
ELSA, Bonn, Germany
S. Aderhold
DESY, Hamburg, Germany

Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale".
In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.

TUPC076

Realization of a High Bandwidth Bunch Arrival-time Monitor with Cone-shaped Pickup Electrodes for FLASH and XFEL

electron, laser, coupling, free-electron-laser

1177

A. Angelovski, M. Hansli, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M. Bousonville, H. Schlarb
DESY, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA
In the Free Electron Laser in Hamburg (FLASH) an electro-optical system is used as a Bunch Arrival time Monitor (BAM). The time-of-arrival resolution is proportional to the steepness of the beam pick-up signal at the first zero-crossing*. Future experiments will be conducted using significantly lower bunch charges resulting in a reduced signal steepness. This requires BAM pickup electrodes with increased bandwidth as introduced in **. This paper presents the implementation and measurement results of a high bandwidth cone-shaped pickup capable of operating in the frequency range up to 40 GHz. The slope steepness at the zero crossing is investigated for a simplified equivalent circuit model. RF-measurements have been performed using a non-hermetic prototype of the BAM pickups for assessing the influence of manufacturing tolerances on the sensor performance. The measurements are compared to simulation results obtained by CST PARTICLE STUDIO®.
* F. Loehl et al., Proc. of DIPAC2007, WEPB15, p. 262 (2007).
** A. Angelovski et al., "Pickup design for a high resolution Bunch Arrival time Monitor for FLASH and XFEL", DIPAC2011.

TUPC079

Sensitivity and Tolerance Analysis of a New Bunch Arrival-time Monitor Pickup Design for FLASH and XFEL

simulation, laser, electron, free-electron-laser

1186

A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M. Bousonville, H. Schlarb
DESY, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Supported by the Graduate School of Computational Engineering at TU Darmstadt and the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Electron Laser in Hamburg (FLASH) is equipped with Bunch Arrival Time Monitors (BAM)*, which provide for a time resolution of less than 10 fs for bunch charges higher than 0.2 nC. Future experiments, however, will aim at generating FEL light pulses from a broad range of bunch charges down to 10 pC. In these circumstances the requirements on the time resolution will no longer be fulfilled, which demands for a larger bandwidth of the pickup system. A new cone-shaped pickup, which has a bandwidth greater than 40 GHz has been proposed**. At high frequencies, small manufacturing tolerances might have great influence on the pickup signal. A sensitivity analysis of several manufacturing tolerances in the pickup design regarding their influence on the output signal was carried out (by means of CST PARTICLE STUDIO®). These results are utilized for setting limits to the manufacturing tolerances.
* M.K. Bock et al., IPAC2010, WEOCMH02, Kyoto, Japan, 2010.
** A. Kuhl et al., "Design eines hochauflösenden Ankunftszeitmonitor für FLASH", DPG Frühjahrstagung 2011, Karlsruhe, Germany.

TUPC080

Pickup Design with Beta Matching

impedance, simulation, resonance, kicker

1189

J.A. Tsemo Kamga, W.F.O. Müller, K.K. Stavrakakis, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Work supported by GSI
The main goal of this project is to investigate the Schottky noise of an ion beam in the frequency range from 3 to 5 GHz. In order to accomplish this task, a pickup design is required. For an efficient study of this Schottky noise the pickup sensitivity for low beta must be increased. A design for such a problem has been developed by McGinnis for a fixed beam velocity but can also be used for variable beta by using a tunable material (ferroelectric) inside the waveguide. Since such tunable materials like for instance BST (Barium Strontium Titanate) are lossy, the impact of dielectric losses on the pickup sensitivity will also be investigated in this work. Additionally to the classical parameter studies where multiple simulation runs based on the original numerical model are initiated to characterize the various design parameters it is also possible to utilize a reduced model instead. In particular one is interested in a fast evaluation of the frequency response while taking also material variations into account. In this work, a multivariate parameterized dynamical system is set up and used complementary to the full model for the required beam characterization.

TUPC082

Beam Current Measurements at the TSR Heidelberg

ion, acceleration, electron, storage-ring

1195

M. Grieser, S.T. Artikova, K. Blaum, F. Laux, J. Ullrich
MPI-K, Heidelberg, Germany

To conduct experiments using low energy ion beams at the TSR heavy ion storage ring, the beam deceleration process must be well understood. During deceleration of the beam the revolution frequency decreases, resulting in low current, which is difficult to measure with a common DC transformer. The number of particles in a bunch is determined by measuring the voltage signal in the time domain using a capacitive pick-up. If the ratio of bunch length and RF period does not change during the deceleration or acceleration, measuring the pick-up signal spectrum, where the signal is directly proportional to the number of particles in a bunch, is a more sensitive method. An alternative method is using a beam profile monitor (BPM) for determining the number of particles in the storage ring via ionization rate measurements of the residual gas. A summary of these different methods to determine the number of particles is presented.

TUPC115

Application of Libera Brilliance Single Pass at NSRL Linac BPM System

brilliance, linac, controls, injection

1284

J.Y. Zou, J. Fang, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Libera Brilliance Single Pass is a digital beam position processor with capabilities of single pass position measurement. This device can be used on the stripline beam position monitor (BPM) of the linac and transfer lines on light sources as well as injector system for the FELs. The linac of Hefei light source (HLS) was equipped with 2 stripline beam position monitors, which will be increased to 20 BPMs after upgrading. The existing BPM electronics were the homemade electronics with logarithm detector. To enhance the functionality of the BPM system, the Libera Brilliance Single Pass is employed to replace the existing BPM electronics. The newly buying devices have made test of characterization. The mapping of stripline BPM is made on a workbench with Libera Brilliance Single Pass. The beam position is tested at linac using Libera Brilliance Single Pass. And the results of these measurement performed on Libera are reported to compared to measurements with the linac’s existing BPM electronics.

TUPC125

Test of the Front-end Electronics and Acquisition System for the LIPAC BPMs

EPICS, controls, linac, LLRF

1311

D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo
ESS-Bilbao, Zamudio, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, I. Podadera
CIEMAT, Madrid, Spain
V. Etxebarria, J. Jugo, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
N. Garmendia, L. Muguira
ESS Bilbao, Bilbao, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
Non-interceptive Beam Position Monitors pickups (BPMs) will be installed along the beamlines of the IFMIF/EVEDA linear prototype accelerator (LIPAC) to measure the transverse beam position in the vacuum chamber in order to correct the dipolar and tilt errors. Depending on the location, the BPMs response must be optimized for a beam of 175 MHz bunch repetition, an energy range from 5 up to 9 MeV, a current between 0.1 and 125 mA and continuous and pulse operation. The requirements from beam dynamics for the BPMs are quite stringent, aiming for the position an accuracy below 100 μm and a resolution below 10 μm, and for the phase an accuracy below 2° and a resolution below 0.3°. To meet these specifications, the BPM electronics system developed by ESS-Bilbao has been adapted for its use with the BPMs of LIPAC. This electronics system is divided in an Analog Front-End unit, where the signals are conditioned and converted to baseband, and a Digital Unit to sample them and calculate the position and phase. The electronics system has been tested at CIEMAT with a wire test bench and a prototype BPM. In this contribution, the tests performed will be fully described and the results discussed.

TUPC130

Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN

quadrupole, monitoring, linac, beam-transport

1326

J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe
IFIC, Valencia, Spain
S. Döbert
CERN, Geneva, Switzerland

Funding: Funding Agency: FPA2010-21456-C02-01
A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC134

Phase Detection Electronics for CLIC

controls, linac, luminosity, linear-collider

1338

A. Andersson
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) requires very tight RF phase synchronisation in order to preserve high luminosity. The electronics required for processing the signals delivered from the phase pick-ups present a significant challenge. This paper discusses the strategy adopted to achieve a sufficiently accurate measurement of the phase. Performance measurements performed in the lab of some of the sub-systems are also presented.

TUPC155

Optimisation of the LHC Beam Current Transformers for Accurate Luminosity Determination

luminosity, instrumentation, monitoring, synchrotron

1395

J-J. Gras, D. Belohrad, M. Ludwig, P. Odier
CERN, Geneva, Switzerland
C. Barschel
RWTH, Aachen, Germany

During the 2010 and 2011 LHC runs a series of dedicated fills were used for luminosity calibration measurements at each of the LHC experiments. A major contribution to the final precision of these luminosity calibration campaigns originated from the absolute accuracy of the bunch current population estimation. The importance of these measurements for the LHC physics community triggered a large and fruitful collaboration between the CERN Beam Instrumentation Group and the LHC Experiments to push the LHC Beam Current Transformers performance to their limit. This paper will report on the available instruments for beam current measurements, the methodology used to improve them and the results obtained.

TUPC163

Experimental Results from Test Measurements with the USR Beam Position Monitoring System

simulation, storage-ring, vacuum, alignment

1416

J. Harasimowicz, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Harasimowicz, I. Takov
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328.
A diagonal-cut capacitive pick-up (PU) was optimised for monitoring slow (v < 0.025c), long (~1 m) bunches consisting of only about 10⁶ antiprotons at the future Ultra-low energy Storage Ring (USR). Ultra-low noise (0.5 nV/Hz⁰.5) FET pre-amplifiers are used to allow detection of the weak signals generated in the PU plates. The amplified signals are then digitized by a 16-bit, 200 MS/s ADC and processed in a digital manner. The following contribution presents the beam monitoring system as it was tested with a stretched-wire method and compares the measurements with the results from 3D electromagnetic simulations.

TUPC172

Evaluation and Correction of the Non-linear Distortion of CEBAF Beam Position Monitors

electron, simulation, radiation

1440

M. Spata, T.L. Allison, K.E. Cole, J. Musson, J. Yan
JLAB, Newport News, Virginia, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The beam position monitors at CEBAF have four antenna style pickups that are used to measure the location of the beam. There is a strong nonlinear response when the beam is far from the electrical center of the device. In order to conduct beam experiments at large orbit excitation we need to correct for this nonlinearity. The correction algorithm is presented and compared to measurements from our stretched wire BPM test stand.

TUPS035

LHC Collimators with Embedded Beam Position Monitors: A New Advanced Mechanical Design

alignment, collimation, simulation, radiation

1611

A. Dallocchio, A. Bertarelli, C.B. Boccard, F. Carra, M. Gasior, L. Gentini, M.A. Timmins
CERN, Geneva, Switzerland

The LHC collimation system, ensuring both functions of beam cleaning and machine protection, is potentially submitted to high-energy beam impacts. Currently the collimators setup is performed by monitoring beam losses generated by the collimator jaws when approaching the particle beam. This procedure is applied to all LHC collimators (almost one hundred), taking several hours, and needs to be repeated if beam settings change significantly. Furthermore, during the beam-based alignment, the LHC tertiary collimators are potentially exposed to abnormal losses entailing possible damage to their tungsten jaws. To improve the efficiency of the machine operation and better control the particle beam a new advanced design embedding Beam Position Monitors (BPM) into the movable collimator jaws has been developed. This paper describes the mechanical design of various types of future collimators with embedded BPMs. Experimental measurements performed on a simplified functional prototype installed in the CERN SPS showed that, thanks to on-board BPMs, the collimator could be precisely, rapidly, and safely aligned and the beam position accurately measured.

TUPS093

Automatic Measurement System for Electrical Verification of the LHC Superconducting Circuits

high-voltage, instrumentation, superconducting-magnet, dipole

1756

A. Kotarba, M. Bednarek, P. Jurkiewicz, J. Ludwin, M. Talach
IFJ-PAN, Kraków, Poland
R. Mompo
CERN, Geneva, Switzerland

In the LHC machine, superconducting magnet circuits are used on a very large scale. The circuits, more than 1600, are all equipped with a complex set of instrumentation required for safe operation and diagnostics. The length of many circuits exceed 3 km. Due to risks of accidental damages during transport and assembly or misconnection of the circuits’ auxiliary components, it is necessary to perform an Electrical Quality Assurance (ELQA) campaign after every major intervention on a circuit and also after each thermal cycle of the machine. In order to be able to perform reliable tests on a circuit within a short time frame, a highly extensible automated mobile test system was designed and built. Four of these instruments were successfully used during the Hardware Commissioning phases of the LHC. This paper describes the hardware solutions used in the test system.

TUPZ022

Longitudinal Beam Measurements at the LHC: The LHC Beam Quality Monitor

injection, controls, emittance, damping

1852

G. Papotti, T. Bohl, F. Follin, U. Wehrle
CERN, Geneva, Switzerland

The LHC Beam Quality Monitor is a system that measures individual bunch lengths and positions, similarly to the twin system SPS Beam Quality Monitor, from which it was derived. The pattern verification that the system provides is vital during the injection process to verify the correctness of the injected pattern, while the bunch length measurement is fedback to control the longitudinal emittance blow up performed during the energy ramp. In 2010 the system could for example clearly detect instances of longitudinal instabilities and beam excitation due to excess RF noise. The algorithms used, the hardware implementation and the system integration in the LHC control infrastructure are presented in this paper, along with possible improvements.

WEPC123

Numerical Algorithm based on the PDE Method for the Solution of the Fokker-Planck Equation

simulation, kicker, storage-ring, impedance

2298

M. Dolinska
NASU/INR, Kiev, Ukraine
C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck
GSI, Darmstadt, Germany

Funding: Work supported by HIC for FAIR
This paper discus a fast and accurate algorithm for numerical solution of Fokker-Planck equation based on the solution of the parabolic Partial Differential Equations (PDE), where the Crank–Nicholson scheme is used. The stability, convergence and round-off errors of the algorithm are studied. The numerical results on Fokker–Planck equation solution with PDE method are compared with other numerical methods. Using the PDE solver, we will be able to predict the stochastic cooling process of notch filter in storage rings.

WEPC135

Recent Developments in Modeling Time-resolved Shielded-pickup Measurements of Electron Cloud Buildup at CESRTA

vacuum, electron, radiation, photon

2313

J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, J.P. Sikora
CLASSE, Ithaca, New York, USA
R.P. Badman
Syracuse University, Syracuse, USA
S. Calatroni, G. Rumolo
CERN, Geneva, Switzerland
S. Kato
KEK, Ibaraki, Japan

Funding: Work supported by the U.S. National Science Foundation PHY-0734867, PHY-1002467 and the U.S. Department of Energy DE-FC02-08ER41538
The Cornell Electron Storage Ring Test Accelerator program includes investigations into the mitigation of electron cloud buildup using a variety of techniques in custom vacuum chambers. The CESR ring accommodates two such chambers equipped with BPM-style pickup detectors shielded against the direct beam-induced signal. The signals provide time-resolved information on cloud development. Results for diamond-like carbon, amorphous carbon, and TiN coatings have been compared to those for an uncoated aluminum chamber. Here we report on extensions to the ECLOUD modeling code which refine its description of a variety of new types of in situ vacuum chamber comparisons. Our results highlight the sensitivity afforded by these measurements to the modeled photoelectron production and secondary yield parameters. We draw conclusions comparing the photoelectron and secondary yield properties of the various vacuum chamber coatings, including conditioning effects as a function of synchrotron radiation dose. We find substantial conditioning effects in both the quantum efficiency for producing photoelectrons and in the secondary yield.

WEPC145

Progress in Developing a PLC Control System for the PKUNIFTY

controls, rfq, cavity, neutron

2331

J. Zhao, J.E. Chen, Z.Y. Guo, Y.R. Lu, S.X. Peng, Q.F. Zhou
PKU/IHIP, Beijing, People's Republic of China

A compact remote PLC control system has been developed for the PKUNIFTY (Peking University Neutron Imaging FaciliTY). That facility is based on a 2 MeV deuteron RFQ accelerator. The PLC control system has been successfully used for the injector including ECR ion source and LEBT, and it worked reliably last year. Now the control of RFQ cavity, HEBT and Be target has been completed and tested. The interlock system has been enhanced. A low level RF control system, including the auto frequency control (AFC) and auto gain control (AGC) circuits, has been designed for the RFQ’s RF power system. Those circuits will work as a lower controller of the PLC control system. The main running parameters can be controlled by setting any desired range of values on the HMI. Test results of hardware and software are presented.

WEPC158

The EMMA Accelerator, A Diagnostic Systems Overview

injection, extraction, diagnostics, EPICS

2355

R.J. Smith, M. Dufau, C. Hill, J.K. Jones, A. Kalinin, L. Ma, P.A. McIntosh, B.D. Muratori, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.S. Berg
BNL, Upton, Long Island, New York, USA
N. Bliss, G. Cox, A. Gallagher, A. Oates
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
R.G. Borrell
WareWorks Ltd, Manchester, United Kingdom
J.L. Crisp
FRIB, East Lansing, Michigan, USA
K.M. Hock, D.J. Holder
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.G. Ibison, I. Kirkman
The University of Liverpool, Liverpool, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The ‘EMMA’ Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) international project is currently being commissioned at Daresbury Laboratory, UK. This accelerator has been equipped with a number of diagnostic systems to facilitate this. These systems include a novel time-domain-multiplexing BPM system, moveable screen systems, a time-of-flight instrument, Faraday cups, and injection/extraction tomography sections to analyse the single bunch beams. An upgrade still to implement includes the installation of a fast wall current monitor. This paper gives an overview of these systems and shows some data and results that have contributed to the successful demonstration of a serpentine acceleration by this novel accelerator.

WEPS007

CNAO Synchrotron Commissioning

synchrotron, extraction, proton, betatron

2496

C. Priano, G. Balbinot, G. Bazzano, J. Bosser, E. Bressi, M. Caldara, H. Caracciolo, L. Falbo, A. Parravicini, M. Pullia, C. Viviani
CNAO Foundation, Milan, Italy
C. Biscari, A. Ghigo
INFN/LNF, Frascati (Roma), Italy

The CNAO (National Center for Oncological Hadrontherapy), located in Pavia, is the first Italian center for deep hadrontherapy with proton and carbon ion beams. The CNAO synchrotron initial commissioning has been carried out using proton beams in the full range of energies: 60 to 250 MeV/u. The first foreseen treatments will need energies between 120 and 170 MeV/u. The nominal proton currents have been reached. The energy scaling of the synchrotron systems and parameters leads to an extracted energy that matches the measured particle range better than 0.1 mm, fitting the treatment requirements, with repeatable beam size and beam current in the treatment room at all investigated energies. A summary of the main results of the synchrotron commissioning is presented.

WEPS041

Tuning of the New 4-Rod RFQ for FNAL

rfq, resonance, simulation, linac

2580

J.S. Schmidt, B. Koubek, A. Schempp
IAP, Frankfurt am Main, Germany

For the injector upgrade at FNAL a 4-rod Radio Frequency Quadrupole (RFQ) with a resonance frequency of 200 MHz has been build. With this short structure of only 1.3 m a very compact injector design has been realized. Simulations with CST Microwave Studio® were performed for the design. Their results leading to the RF characterizations of the RFQ and the final RF setup which has been accomplished at IAP of the Goethe-University Frankfurt are presented in this paper.

THPO006

A Digital Power Supply Control Model in Heavy-ion Accelerator based on Dual Nios Cores

power-supply, controls, ion, heavy-ion

3346

R.K. Wang, Y.X. Chen, D.Q. Gao, Y.Z. Huang, H.B. Yan, H.H. Yan, Z.Z. Zhou
IMP, Lanzhou, People's Republic of China
R.K. Wang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

According to the features of digital power supply and the requirements of pulse mode,this paper introduces a Digital Power Supply Control Mode(DPSCM) in Heavy-Ion Accelerator based on dual Nios cores,which meets the requirements of two basic running modes. The new method develops a system on-chip based on dual Nios cores by using SOPC technology in the Altera EP2C70 FPGA. Compared with traditional DPSCM,the dual Nios cores run simultaneously and cooperate well. As a result,the efficiency of the system is remarkably improved. Further,cores in parallel can realize reference waveforms switch in pulse mode effectively. We choose a 1150A/185V power supply as test bench. The Experimental result indicates that the system can realize the function of pulse mode,and the stability and tracking error meet the design requirements.

THPS003

Status of Stochastic Cooling Predictions at the HESR

antiproton, accumulation, kicker, injection

3430

H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
T. Katayama
GSI, Darmstadt, Germany

Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.