pick-up

Paper	Title	Other Keywords	Page
MOPCH074	Layout of an Accumulator and Decelerator Ring for FAIR	antiproton, injection, kicker, electron	199
	P. Beller, K. Beckert, C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck, J. Yang GSI, Darmstadt
	Antiproton physics and experiments with rare isotope beams are major research fields at FAIR. Antiproton physics requires the accumulation of high intensity antiproton beams. The accumulation of up to 1011 antiprotons at 3 GeV is foreseen. This will be accomplished by the combination of the collector ring CR for stochastic precooling and the specialized accumulator ring RESR. The accumulation scheme in the RESR is based on the usage of a stochastic cooling system. The requirements of this cooling system strongly affect the magnetic structure of the RESR. For experiments with short-lived rare isotope beams the RESR serves the task of fast deceleration. Precooled rare isotope beams will be injected at 740 MeV/u and then decelerated to energies between 100 and 400 MeV/u in less than 1 s. This contribution presents the ring design and lattice studies relevant for both tasks of the ring as well as a description of the antiproton accumulation scheme.
MOPCH077	The Collector Ring CR of the FAIR Project	kicker, antiproton, injection, extraction	208
	F. Nolden, K. Beckert, P. Beller, U. Blell, C. Dimopoulou, A. Dolinskii, U. Laier, G. Moritz, C. Muehle, I. Nesmiyan, C. Peschke, M. Steck GSI, Darmstadt
	The Collector Ring is a storage ring in the framework of the FAIR project. It has the purpose of stochastic precooling of both rare isotope and antiproton beams and of measurung nuclear masses in an isochronous setting. The paper discusses progress in the development of magnet systems, rf systems, injection/extraction strategies and stochastic cooling systems. Finally it is discussed how to confirm the predicted performance of the slotline electrodes developed recently for stochastic cooling.
MOPCH085	Pickup Structures for the HESR Stochastic Cooling System	COSY, vacuum, kicker, ion	228
	R. Stassen, P.B. Brittner, G. Schug, H.S. Singer FZJ, Jülich
	The design of the High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt includes electron and stochastic cooling. Simulations have shown that the bandwidth of a 2-4 GHz stochastic cooling system is sufficient to achieve the requested beam parameter at the internal target. New 2-4 GHz pickup structures have been developed and tested. First results of the low impedance, printed loop structures will be presented.
MOPCH086	Stochastic Cooling for the HESR at the GSI-FAIR Complex	target, antiproton, emittance, kicker	231
	H. Stockhorst, B. Lorentz, R. Maier, D. Prasuhn FZJ, Jülich T. Katayama CNS, Saitama
	The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt is planned as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combi-nation of phase space cooled beams with internal targets. The required beam parameters and intensities are prepared in two operation modes: the high luminosity mode with beam intensities up to 1011 and the high reso-lution mode with 1010 anti-protons cooled down to a relative momentum spread of only a few 10-5. In addition to electron cooling, transverse and longitudinal stochastic cooling are envisaged to accomplish these goals. It is shown how the great benefit of the stochastic cooling system to adjust the cooling force in all phase planes independently is utilized to achieve the requested beam spot and the high momentum resolution at the internal target within reasonable cooling down times for both HESR modes even in the presence of intra-beam scattering. A numerical and analytical approach to the Fokker-Planck equation for longitudinal filter cooling has been carried out.
MOPCH149	Microphonics Measurements in a CW-driven TESLA-type Cavity	resonance, cryogenics, klystron, linac	405
	O. Kugeler, W. Anders, J. Knobloch, A. Neumann BESSY GmbH, Berlin
	Superconducting cavities with a high quality factor exhibit a very low bandwidth in their resonant frequency, which makes their operation very sensitive to mechanical oscillations. In CW mode of operation, as is intended for the BESSY-FEL Linac, microphonics are therefore the dominant error source for field stability. In order to compensate the detuning, it is necessary to properly characterize amplitude and frequency with respect to all involved mechanical and electrical components. Such measurements have been performed at the HoBiCaT test facility at BESSY and will be described in detail.
MOPCH155	Performance Limitations of Tesla Cavities in the Flash Accelerator and their Relation to the Assembly Process	vacuum, TESLA, DESY, controls	421
	L. Lilje DESY, Hamburg
	Several accelerator modules with superconducting cavities have been assembled for TTF. The paper reviews the performance of these structures and will try to correlate their performance to information about the assembly process. In some cases a performace degradation could be attributed to problems in this process. The introduction of additional quality control steps improved accelerator module performance. For example, the more recently assembled modules have shown the expected acceleration gradients and no vacuum leaks.
MOPCH164	Status of the Diamond Storage Ring Radio Frequency System	DIAMOND, controls, storage-ring, power-supply	445
	M. Jensen, M. Maddock, S.A. Pande, S. Rains, A. F. Rankin, D. Spink, A.V. Watkins Diamond, Oxfordshire J. Alex, M. Mueller Thomson Broadcast & Multimedia AG, Turgi B. A. Aminov CRE, Wuppertal M. Pekeler ACCEL, Bergisch Gladbach
	The installation and commissioning of the Diamond Storage Ring RF system is nearing completion. Diamond will initially operate with two RF high power amplifiers and two cavities. The key components in each RF system are a 300 kW amplifier implemented through the combination of four 80 kW IOTs, a 500 MHz superconducting cavity providing up to 2 MV of accelerating voltage and an advanced analogue IQ Low Level RF (LLRF) system to control the cavity frequency, voltage and phase. We present here an update on the recent installation and early commissioning results of the RF systems.
MOPCH167	PBG Superconducting Resonant Structures	lattice, radiation, cryogenics, simulation	454
	M.R. Masullo INFN-Napoli, Napoli A. Andreone, E. Di Gennaro, F. Francomacaro, G. Lamura Naples University Federico II, Napoli V. Palmieri, D. Tonini INFN/LNL, Legnaro, Padova M. Panniello, V.G. Vaccaro Naples University Federico II and INFN, Napoli
	We have realized normal conducting and superconducting “open resonators” based on the Photonic Band Gap (PBG) concept. We present the study, the optimisation and the measurements (from room temperature to 1.5 K) of Copper and Niobium PBG accelerating cavities operating at two different frequencies, 6 GHz and 16 GHz. All the structures are realised by extruding a single bulk piece of material, using a new machining method that minimizes the surface losses caused by the contact between different conducting parts. Measurements on the compact (54 mm external diameter) 16 GHz Nb structure are very good, showing in the superconducting state a quality factor Q =1.2x105 at the lowest temperature (1.5 K), limited by radiation losses only. The shunt impedance measured for the 16 GHz prototype is 70 MOhm/m, underlining the applicability of such resonant structures as accelerating cavities.
MOPLS083	Higher Order Mode Study of Superconducting Cavity for ILC Baseline	KEK, polarization, coupling, dipole	747
	K. Watanabe GUAS/AS, Ibaraki H. Hayano, E. Kako, S. Noguchi, T. Shishido KEK, Ibaraki
	The superconducting cavity of ILC baseline shape is being developed at KEK-STF (Superconducting RF Test Facility). The Higher Order Mode (HOM) of the cavity is one study item for the development. The purpose of the HOM study is further optimization of TTF HOM coupler and measurement of the HOM field distribution and the polarization of the main dipole modes. The result will be applied to HOM readings of beam induced signal for the purpose of cavity offset position and angle of axis measurement relative to the beam. We tried to improve of TESLA-type HOM coupler for more small size and relaxation of second stop-band. The cold-model coupler was made, and the RF characteristic was measured. After HOM couplers welded to the KEK Baseline nine-cell SC cavity, Qext of fundamental mode and each HOM, field pattern of each HOM and polarization of dipole modes were measured by the network analyzer. The results of the improved HOM coupler are presented.
MOPLS087	Series Test of High-gradient Single-cell Superconducting Cavity for the Establishment of KEK Recipe	KEK, vacuum, electron, superconductivity	756
	T. Saeki, F. Furuta, Y. Higashi, T. Higo, S. Kazakov, H. Matsumoto, Y. Morozumi, K. Saito, N. Toge, K. Ueno, H. Yamaoka KEK, Ibaraki M.Q. Ge IHEP Beijing, Beijing K. Kim Kyungpook National University, Daegu R.S. Orr University of Toronto, Toronto, Ontario
	We have performed a series of vertical tests of single cell Niobium superconducting cavities at 2 degrees Kelvin. These tests aimed at establishing the feasibility of reaching an accelerating gradient of 45 MV/m on a routine basis. The cavity profiles were all of the KEK low loss design and were fabricated from deep drawn Niobium half shells using electron beam welding. The cavity surface preparation followed an established KEK procedure of centrifugal barrel polishing, light chemical polishing, high temperature annealing, electropolishing, and finally a high pressure water rinse. Of the six cavities tested, three exceeded 45 MV/m on the first test. This clearly establishes the feasibility of this gradient. In this paper we describe these tests and our future program for optimising the surface preparation.
TUPCH007	High Resolution BPM for the Linear Colliders	dipole, DESY, simulation, collider	1004
	C. Simon, S. Chel, M. Luong, O. Napoly, J. Novo, D. Roudier CEA, Gif-sur-Yvette N. Rouvière IPN, Orsay
	The beam-based alignment and feedback systems which are essential for the operation of the future colliders use some high resolution Beam Position Monitors (BPM). In the framework of CARE/SRF, the task of CEA/DSM/DAPNIA (Saclay) is the design, the fabrication and the beam test of a BPM in collaboration with DESY. This system is composed of a RF re-entrant cavity with a beam pipe radius of 78mm and an analog electronics having several signal processing steps to reject the monopole mode. Thanks to its high position resolution (better than 1μm) and its high time-resolution (around 10ns), it is a candidate for the X-FEL at DESY and the ILC. Indeed the chosen coupling allows the bunch to bunch measurement and the separation between the monopole and dipole modes. Moreover, this BPM is designed to be used in a clean environment, at the cryogenic and room temperatures.
TUPCH012	Digital Techniques in BPM Measurements at GSI-ISI	acceleration, feedback, synchrotron, GSI	1019
	A.A. Galatis, P. Kowina, K. Lang, A. Peters GSI, Darmstadt
	In this paper we describe new approaches for BPM measurements in hadron accelerators, which have strongly varying beam parameters such as intensity, accelerating frequency and bunch length. Following signal dynamic adjustment, direct digitalization and treatment of digitized data, we should reach a BPM resolution of 0.1mm. Interchangeability of this method between accelerators should be provided, which results in autonomous data treatment algorithms, free of external status and timing signalling. This should ensure the usability of the system in other bunched accelerator rings. Different operation modes are intended for allowing online storage of beam position data over full acceleration cycles as well as storage of beam waveforms in regions of acceleration that are of special interest e.g. transition, kicking, bunch gymnastics. First results of realised hardware/software combinations will be introduced and discussed.
TUPCH013	Numerical Calculations of Position Sensitivity for Linear-cut Beam Position Monitors	simulation, vacuum, coupling, CERN	1022
	P. Kowina, A.A. Galatis, W. Kaufmann, J. Schoelles GSI, Darmstadt
	In this contribution the results of simulations performed for different geometries of linear-cut Beam Position Monitors (BPMs) are compared for two design types: i)based on metal electrodes and ii)using a metal coated ceramics. The advantage of the ceramic solution is a compact construction allowing easy positioning. Contrary, the construction based on the metal electrodes benefits from its simplicity. The main goals in optimization are the sensitivity and linearity of the position determination. High position sensitivity can be achieved by the reduction of the plate-to-plate cross talks caused by coupling capacities. For instance, the insertion of an additional guard ring into the gap between the active plates leads to an increase of the sensitivity by about 30%. This insertion is necessary in case of ceramic solution: The large ceramics permeability enlarges the coupling capacity by about a factor of four. The careful geometrical arrangement allows to avoid resonances in the interesting frequency range i.e. from 0.2 to 200MHz. The displayed simulations are performed using CST Microwave Studio. The investigated BPMs will be used in the FAIR facility presently under design at GSI.
TUPCH022	Large Horizontal Aperture BPM for use in Dispersive Sections of Magnetic Chicanes	simulation, electron, laser, SMA	1043
	K.E. Hacker, H. Schlarb DESY, Hamburg F. Loehl Uni HH, Hamburg
	A beam position monitor with a large horizontal aperture for use in dispersive sections of FLASH magnetic chicanes will be installed in October 2006. It has a horizontal range of 13 cm and a resolution requirement of better than 10 microns. A stripline design mounted perpendicularly to the the electron beam direction is used to provide broadband electrical pulses traveling in opposite directions, the phases of which give a measure of the beam position. The phase measurement will be accomplished through an optical method developed for a beam arrival time monitor. Results from simulation and recent beam arrival-time measurements will be used to justify expectations for the BPM performance.
TUPCH030	A Beam Diagnostics System for the Heidelberg Cryogenic Storage Ring CSR	CSR, ion, diagnostics, electron	1067
	T. Sieber, H. Fadil, M. Grieser, A. Wolf, R. von Hahn MPI-K, Heidelberg
	The storage of rotationally non-excited molecules and highly charged ions requires lowest temperatures and vacuum pressures. At the MPI-K Heidelberg a cryogenic storage ring (CSR) for atomic and molecular physics experiments is under development. The CSR shall allow operation at temperatures of 2 K and pressures down to 1·10-15 mbar. The ring consists of electrostatic elements and has a circumference of ~35 m. It is housed inside a large cryostat, cooled by a (20W @ 2K) Helium refrigerator. To reach low UHV pressures already at room temperature the whole machine has to be bakeable up to 300°C. These boundary conditions, together with the low charge states, low velocities and low intensities (1nA-1muA) of the ions, put strong demands on the beam diagnostics system. Some beam parameters like profile, position and intensity cannot be measured with “standard” beam diagnostics technology. Here new or further developments are required. The paper gives a general view of the beam diagnostics concept for the CSR and shows in more detail possible solutions for measurement of beam position and beam profile.
TUPCH031	A New SQUID-based Measurement Tool for Characterization of Superconducting RF Cavities	cryogenics, electron, shielding, TESLA	1070
	K. Knaack, K. Wittenburg DESY, Hamburg R. Neubert, S. Nietzsche, W. Vodel FSU Jena, Jena A. Peters GSI, Darmstadt
	In this contribution a LTS-SQUID based measurement tool for characterization of superconducting RF cavities for the upcoming X-FEL project at DESY will be presented. The device makes use of the Cryogenic Current Comparator (CCC) principle and measures the so-called dark current, generated e.g. by superconducting cavities at high voltage gradients. To achieve the maximum possible energy the gradients should be pushed near to the physical limit of 50 MV/m. The measurement of the undesired field emission of electrons (the so-called dark current) in correlation with the gradient will give a proper value to characterize the performance of the RF cavities. The CCC mainly consists of a high performance LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted dark current of the RF cavities. Therefore, a special designed toroidal niobium pick-up coil for the passing electron beam is superconducting connected across the input coil of the SQUID. The noise limited sensitivity of the CCC as well as new experimental results with the whole measurement device assembled in a special wide-necked LHe cryostat will be presented.
TUPCH052	Turn by Turn Measurements at DAFNE Based on the Libera Beam Position Processor	betatron, injection, kicker, controls	1124
	A. Stella, M. Serio INFN/LNF, Frascati (Roma)
	The BPM detection electronics developed by Instrumentation Techonologies implements digital receivers technology to measure beam position from the amplitude of pick-up signals. Besides the closed orbit mode, the Libera module can be operated also in the Turn-by-Turn mode. Operational experience with Libera at DAFNE, the Frascati e+ e- collider, has been focused on this functionality. Data obtained from DAFNE have been processed with well established extraction algorithms to accurately measure the betatron tunes from a small number of turns, providing instantaneous information on tune variations occurred also in fast damped decays after a kick. Hardware and software implementation together with experimental data are reported.
TUPCH054	Upgrade of Signal Processing of the BPM System at the SPring-8 Storage Ring	target, storage-ring, synchrotron, acceleration	1130
	T. Fujita, S. Sasaki, M. Shoji, T. Takashima JASRI/SPring-8, Hyogo-ken
	SPring-8 is a third generation synchrotron light source, which is operated stably with top-up mode and with optics of low emittance mode. Along with stabilization of electron beam orbit in the ring, upgrading of the BPM system has also been required. We have developed a new signal processing circuit for COD measurement with a target of a few microns of position resolution at 1 kHz band-width and a few hundreds per second to take beam position of all BPMs. In the new circuit, a multiplexing method is employed and the IF frequency is directory detected with a 2MSPS 16-bit ADC. The digitized signal is processed with DSP to obtain beam position. Analog components of the circuit are equipped in a temperature controlled cabinet in order not to be affected by fluctuation of ambient temperature. In this paper we report schematics and performance of the new circuit, e.g., dependence of position resolution on measurement band-width and long time stability, etc. In addition, we briefly describe possibility of fast orbit measurement as a further application of the circuit.
TUPCH055	Beam Phase Measurement of Stored Bunch	controls, insertion, insertion-device, injection	1133
	T. Ohshima, A. Yamashita JASRI/SPring-8, Hyogo-ken M. Yoshioka SES, Hyogo-pref.
	We developed a system to measure synchronous phase angles for all bunches stored in the storage ring using an oscilloscope with high sampling rate. Precise phase measurement of specific bunch is required from the synchrotron radiation (SR) users, especially from the time resolved spectroscopy users. In a pump and probe experiment, the trigger timing for pumping laser should be precisely adjusted to the probe SR light. The timing of SR light is affected by the accelerating RF voltages, filling pattern, bunch currents, gap positions of insertion devices and so on. At the SPring-8, the bunch currents and the synchronous phase angles for all stored bunches can be measured within 30seconds using newly developed system. The precision of the phase angle is less than 8ps. We are now preparing to deliver the information of synchronous phase angle to SR users. The detail of the measurement system and achieved performance will be presented.
TUPCH059	Dual-mode Beam Current Monitor	impedance, feedback, injection, shielding	1145
	S. Ninomiya, T. Adachi, S. Fukumoto KEK, Ibaraki S.H. Hatori, T. Kurita WERC, Tsuruga , Fukui
	A new type HEREWARD-transformer is developed. The original scheme connects pickup coil to the low impedance input of the amplifier to increase the time constant of the transformer. The new scheme employs negative impedance circuit which realizes perfect cancellation of the coil resistance. Therefore DC component of the beam current can be observed. Since number of winding of the pick up coil is only 100-turns, therefore by using the original scheme with a fast operational amplifier, the transformer can be operated at fast CT mode. Thus the dual mode operation can be realized by single core; the first mode is the slow beam intensity monitor, and the second is a fast response transformer. This operation mode realizes an accurate observation of the beam injection process. In order to make installation easy, the core is divided into two pieces. The magnetic shield from bending field is also installed. This monitor is developed at KEK, and installed into the accelerator at the WAKASA WAN Energy Research Center.
TUPCH061	Installation of Beam Monitor Sensors in the LINAC Section of J-PARC	linac, quadrupole, KEK, vacuum	1151
	S. Sato, H. Ao, T. Tomisawa, A. Ueno JAEA/LINAC, Ibaraki-ken H. Akikawa JAEA, Ibaraki-ken Z. Igarashi, S. Lee KEK, Ibaraki
	In the LINAC section of J-PARC, we have several type of sensors of monitor, i.e, Beam Position Monitor, Beam Profile Monitor, Beam Size Monitor, Current Monitor, Beam Phase Monitor, Beam Loss Monitor. Those sensors are being installed currently. The procedures, remarks during the installation, status are described in this paper. As an examle, the beam postion monitors are one of sensors which are taken cared intensively for their positioning on their housing quadrupole magnet, then our cares during their installation are described .
TUPCH077	Beam Phase Measurement in a 200 MeV Cyclotron	cyclotron, extraction, injection, controls	1187
	J.L. Conradie, A.H. Botha, P.J. Celliers, J.L.G. Delsink, D.T. Fourie, P.T. Mansfield, P.F. Rohwer, M.J. Van Niekerk iThemba LABS, Somerset West J. Dietrich, I. Mohos FZJ, Jülich
	New phase measuring equipment is being planned for the K 200 variable frequency, separated-sector cyclotron at iThemba LABS near Cape Town. A commercial lock-in amplifier is used to measure the beam phase over the full radial range. Measurements are made at the third and fifth harmonics of the main RF frequency to limit pick-up from the flat-topping and main dees. Computer-generated signals, with phase and amplitude control, at the same harmonics, are used to cancel the signals coupled from the dees to the phase probes. In addition the signals without beam are vectorially subtracted from those with beam to enhance the sensitivity and accuracy. Results of measurements, using these techniques, on existing phase probes in the cyclotron, will be presented.
TUPCH078	BPM Design for the ALBA Synchrotron	impedance, booster, vacuum, storage-ring	1190
	F. Pérez, A. Olmos ALBA, Bellaterra T.F. Günzel ESRF, Grenoble
	ALBA is a 3 GeV, low emittance, 3rd generation synchrotron light source that is in the construction phase in Cerdanyola, Spain. Vertical beam sizes down to a few microns will require beam stabilities on the submicron level. The BPM has to be designed in order to provide reliable and accurate beam position readings. Simulation and computational codes have been used to optimise, for a given vacuum chamber dimension, the BPM design. The optimisation has taken into account the usual sensitivity and intrinsic resolution parameters, but as well, the wakefield loss factor of the buttons. Due to the small vertical vacuum chamber dimension and the high design current, the beam power deposited in the buttons is becoming a concern due to the thermal deformation effects that can introduce errors at the submicron level. A compromise between a higher intrinsic resolution from one side, and a low power deposited by the beam in the buttons from the other, define the final buttons dimensions.
TUPCH080	Bunched Beam Current Measurements with 100 pA rms Resolution at CRYRING	CRYRING, acceleration, ion, background	1196
	A. Paal, A. Simonsson MSL, Stockholm J. Dietrich, I. Mohos FZJ, Jülich
	In CRYRING molecular beams with currents down to 1 nA are used for experiments. To extend the rms resolution of the bunched beam current measurements down to 100 pA, a BERGOZ Integrating Current Transformer (ICT) and one of the the capacitive pick-up's sum signal are integrated simultaneously. The absolute calibration of the pick-up integrator signal is carried out at the end of the acceleration stage, during 20-60 ms. The ion beam current can be measured over a pulse width range of 100 ns to 15 us with a 20-60% bunch duty cycle. For both detectors, low noise amplifiers and a differential input double integrator have been designed. A programmable phase shifter allows measurement of the beam current during the acceleration of the ions, generating a gate signal with proper phase for the integrators in the 30 kHz-3 MHz frequency range. The bandwidth of the integrators used is 100 Hz.
TUPCH082	The EuroTeV Confocal Resonator Monitor Task	coupling, CTF3, vacuum, resonance	1202
	V.G. Ziemann, T. J. C. Ekelof, A. Ferrari, M. A. Johnson, E. A. Ojefors, A. B. Rydberg UU/ISV, Uppsala F. Caspers CERN, Geneva
	We describe the progress in the analysis of the confocal resonator monitor task which is part of the diagnostics workpackage of EuroTeV. The initial design was analyzed both numerically and experimentally and found limitations. We therefore digressed from strict confocality and report the numerical analysis and S-parameter measurements of a modified design. Furthermore, we discuss the mechanical design needed for planned tests with beam in CTF3 which requires integration of the monitor into the beam pipe, damping of trapped modes, and frequency tunability.
TUPCH086	Precision Beam Timing Measurement System for CLIC Synchronization	CLIC, CTF3, linac, CERN	1211
	J.P.H. Sladen, A. Andersson CERN, Geneva
	Very precise synchronization between main and drive beams is required in CLIC to avoid excessive luminosity loss due to energy variations. One possibility to accomplish this would be to measure and correct the drive beam phase. The timing reference for the correction could be the beam in the transfer line between the injector complex and the main linac. The timing of both main and drive beams will have to be measured to a precision in the region of 10 fs. The aim is to achieve this by means of a beam measurement at 30 GHz with the signal mixed down to an intermediate frequency (IF) for precise phase detection. The RF and IF electronics are being developed and tests will be carried out in CTF3.
TUPCH087	Beam Diagnostics with Schottky Noise in LEIR	ion, CERN, injection, diagnostics	1214
	J. Tan, G. Tranquille CERN, Geneva
	The high density Lead ion beams, needed for LHC, are obtained in the Low Energy Ion Ring (LEIR) at CERN by multi-turn injection followed by electron cooling and stacking. During this injection and stacking phases where the circulating beam is unbunched, diagnostics with Schottky noise are used for probing essential beam parameters, such as tune, momentum spread, emittance and their evolution with time… The hardware facility and first results obtained during the recent commissioning of LEIR are described.
TUPCH092	Commissioning of a New Digital BPM System for the PSI Proton Accelerators	proton, cyclotron, controls, instrumentation	1226
	B. Keil, P.-A. Duperrex, M. U. Müller PSI, Villigen
	A new digital beam position monitor (DBPM) system has been developed and successfully tested at the PSI proton accelerators. The DBPM hardware consists of an analogue RF front-end (RFFE), a VMEbus backplane module (VBM), and the PSI VME PMC Carrier board (VPC). The RFFE combines the 2nd RF harmonic (101.26 MHz) beam signals of pickup coils with a 101.31 MHz pilot signal. The RFFE output signals are undersampled and down-converted to base-band (no analogue mixer) by ADCs and DDCs (Direct Digital Downconverters) on the VBM. The DDCs send the digitised beam and pilot signal amplitudes to a Virtex2Pro FPGA on the VPC board. The FPGA calculates the beam positions at different averaging rates, checks interlock limits, and provides triggered storage of beam position waveforms. Furthermore, the FPGA performs automatic gain control of voltage-controlled amplifiers (VCAs) of RFFE and VBM. By continuous normalisation of beam to pilot signal, nonlinearities and temperature drifts of the electronics are eliminated. Compared to the old analogue BPM electronics, the new DBPMs offer an increased dynamic range (0.2 μA to 2 mA instead of 5 μA to 2 mA) and larger bandwidth (10 kHz instead of 10 Hz).
TUPCH120	The Diamond Light Source Booster RF System	booster, controls, DIAMOND, synchrotron	1295
	C. Christou, V.C. Kempson Diamond, Oxfordshire K. Dunkel ACCEL, Bergisch Gladbach A. Fabris ELETTRA, Basovizza, Trieste
	The Diamond Light Source (DLS) accelerator complex can be divided into three major components; a 3 GeV 561 m circumference storage ring, a 158.4 m circumference full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the design and presents commissioning results of the RF system for the booster synchrotron. Booster RF commissioning took place in late 2005 and early 2006 and involved the setting-into-operation of a 60 kW IOT amplifier, supplied by Thales Broadcast and Multimedia, a 5-cell copper cavity, manufactured by Accel Instruments, and a low-level RF system designed and built by Sincrotrone Trieste SCpA.
TUPCH147	High Pressure RF Cavities in Magnetic Fields	klystron, vacuum, ion, resonance	1364
	P.M. Hanlet, M. Alsharo'a, R. E. Hartline, R.P. Johnson, M. Kuchnir, K. Paul Muons, Inc, Batavia C.M. Ankenbrandt, A. Moretti, M. Popovic Fermilab, Batavia, Illinois D.M. Kaplan, K. Yonehara Illinois Institute of Technology, Chicago, Illinois
	A study of RF breakdown in pressurized cavities immersed in strong magnetic fields has begun as part of a program to develop RF cavities filled with dense hydrogen gas to be used for muon ionization cooling. A pressurized 805 MHz test cell is being used at Fermilab to compare the conditioning and breakdown behavior of copper, molybdenum, and beryllium electrodes as functions of hydrogen and helium gas densities and magnetic field strength. These results will be compared to the predicted or known RF breakdown behavior of these metals in vacuum with and without external magnetic fields.
TUPLS001	Enhanced Optical Cooling of Ion Beams for LHC	ion, undulator, kicker, betatron	1483
	E.G. Bessonov, M.V. Gorbunkov LPI, Moscow A.A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	Enhanced optical cooling (EOC) of fully stripped lead ions in LHC is investigated. The method of EOC is based on the usage of pickup and kicker undulators and optical amplifier. External selectivity is arranged by a moving screen located on the image plane of the optical system, projecting the emitted undulator radiation there (see physics/0509196). Nonlinear features of cooling and requirements to the ring lattice, optical and laser systems are discussed. Comparison with classical optical stochastic cooling (OSC) is represented as well.
TUPLS040	Tuning of a 4-rod CW-mode RFQ Accelerator	rfq, acceleration, resonance, vacuum	1583
	P. Fischer, A. Schempp IAP, Frankfurt-am-Main
	A four-rod RFQ accelerator has been built which operates in CW mode with a power consumption of 250 kW. The assembly of a high power RFQ structure requires a precise mechanical alignment and field tuning of the electrode field. The field distribution must be very flat to enable a proper operation with few losses. Adjusting of the field distribution is critical in long structures. Simulations and the status of the tuned structure will be discussed.
TUPLS042	First Cryogenic Tests of the Superconducting CH-structure	cryogenics, GSI, resonance, coupling	1588
	H. Podlech, C. Commenda, H. Klein, H. Liebermann, U. Ratzinger, A.C. Sauer IAP, Frankfurt-am-Main
	The CH-structure is a new multi-cell drift tube structure operated in the TE21-mode and is well suited for the acceleration of low and medium beta ion and proton beams. Due to the mechanical stiffness room temperature as well as superconducting CH-cavities can be realised. A 19-cell, beta=0.1 superconducting CH-prototype cavity has been developed and built. First cryogenic tests have been performed at 4.5 K in Frankfurt successfully. An effective accelerating voltage of 3.6 MV has been achieved so far. This corresponds to an electric peak field of 23 MV/m. Actual measurements aim on a localisation of possible field emission centers, afterwards further surface preparation will take place.
WEPLS098	Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine	LHC, dipole, quadrupole, octupole	2604
	D. Bozzini, V. Chareyre, K.H. Mess, S. Russenschuck CERN, Geneva A. Kotarba, S. Olek HNINP, Kraków
	The coherence between the powering reference database and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits of the LHC. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. The parameters measured at ambient temperature such as the dielectric insulation and the impedance transfer function of assembled circuits will be discussed. Some examples of detected polarity errors and the treatment of non-conformities will be presented.
THOBFI01	A Sub 100 fs Electron Bunch Arrival-time Monitor System for FLASH	laser, electron, FEL, DESY	2781
	F. Loehl, K.E. Hacker, F. Ludwig, H. Schlarb, B. Schmidt DESY, Hamburg A. Winter Uni HH, Hamburg
	The stability of free-electron lasers and experiments carried out in pump-probe configurations depends sensitively on precise synchronization between the photo-injector laser, low-level RF-systems, probe lasers, and other components in the FEL. A measurement of the jitter in the arrival-time of the electron bunch with respect to the clock signal of a master oscillator is, therefore, of special importance. For this task, we propose an arrival-time monitor based on a beam pick-up with more than 10GHz bandwidth which permits measurements in the sub 100 fs regime. The RF-signal from the beam pick-up is sampled by an ultra-short laser pulse using a broad-band electro-optical modulator. The modulator converts the electron bunch arrival-time jitter into an amplitude modulation of the laser pulse. This modulation is detected by a photo detector and sampled by a fast ADC. By directly using the laser pulses from the master laser oscillator of the machine, any additional timing jitter is avoided. In this paper we present the layout of the system and first experimental results.
	Transparencies
THPCH048	Transverse Coupled Bunch Instability Driven by 792-MHz Cavity HOM in NewSUBARU Electron Storage Ring	damping, emittance, synchrotron, betatron	2892
	S.H. Hisao, A. Ando, S. Hashimoto, T. Matsubara, Y. Miyahara, Y. Shoji NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
	The 792-MHz HOM of the RF cavity can drive horizontal coupled bunch instability in the NewSUBARU electron storage ring. This instability is now avoided by tuning the HOM frequency with an additional tuner (HOM tuner). Detailed characteristics of this instability were investigated by changing the HOM frequency, betatron tune, chromaticity and magnitude of the stored current at the energy of 1 GeV. The experiments were performed with 6-bunch equi-space filling to clarify the mode number. Bunch oscillations show saw-tooth patterns when the stored current is not so large. The measured results are compared with an analytical calculation using a rigid bunch model and Sacherer's formalism. The fundamental aspects can be well explained by the calculation, but there exist many problems that cannot be explained by the rigid bunch model.
THPCH078	Successful Bunched-Beam Stochastic Cooling in RHIC	kicker, RHIC, ion, proton	2967
	J.M. Brennan, M. Blaskiewicz, F. Severino BNL, Upton, Long Island, New York
	Stochastic Cooling of high energy and high frequency bunched beam has been demonstrated in RHIC at 100 GeV. Narrowing of the Schottky spectrum and shorting of the bunch length resulted from cooling the beam for 90 minutes. The purpose of the stochastic cooling is to counteract the fundamental limit of the luminosity lifetime of heavy ions in RHIC which is Intra-Beam Scattering. IBS drives transverse emittance growth and longitudinal de-bunching. The major components of the system have been tested with heavy ion and proton beams in previous runs in RHIC, demonstrating that the difficult challenges of high frequency bunched beam stochastic cooling can be overcome. The vexing problem of pollution of the Schottky spectrum by coherent components is solved with optimized filtering and high dynamic range low noise electronics. A set of 16 high-Q cavities is used to achieve adequate kicker voltage in the 5 to 8 GHz band. This technique exploits the bunched beam time structure to level the microwave power requirement and enables the use of solid state amplifiers to drive the kickers. Because RHIC did not operate with heavy ions in the FY06 run, the system was tested with specially prepared low intensity protons bunches of 2·109 particles.
THPCH082	Broadband Bunch by Bunch Feedback for the ESRF using a Single High Resolution and Fast Sampling FPGA DSP	feedback, kicker, damping, FIR	2976
	E. Plouviez, P. Arnoux, F. Epaud, J. Jacob, J.M. Koch, N. Michel, G.A. Naylor, J.-L. Revol, V. Serriere, D. Vial ESRF, Grenoble
	In order to increase the current in the ESRF storage ring we have developed a set of multibunch feedback systems aimed at fighting longitudinal and transverse coupled bunch instabilities. The longitudinal feedback (LFB) has been the first system installed and tested. It was designed using the scheme developed at SLAC, ALS and INFN Frascati: bunch by bunch processing of a beam phase error signal and correction using a low Q kicker driven by a QPSK modulator. However, we took advantage for this development of the latest available technology for the signal processing electronics with high resolution, high sampling rate ADC and DAC, and FPGA DSP, as well as for the FPGA programming environment. It allowed us to substantially reduce the complexity: the algorithm runs on a single processor, the kicker requires only 200W of RF power to control a 6GeV beam, and the implementation took only about one year. We will describe the main features of our LFB and present the results already achieved in the damping of instabilities driven by our RF cavity HOM. We will also report on the status of the transverse feedback, which is being built up using the same FPGA system as the longitudinal one.
THPCH096	Intra Bunch Train Feedback System for the European X-FEL	feedback, XFEL, coupling, controls	3017
	V. Schlott, M. Dehler, B. Keil, R. Kramert, A. Lounine, G. Marinkovic, P. Pollet, M. Roggli, T. Schilcher, P. Spuhler, D.M. Treyer PSI, Villigen
	After joining the preparatory phase of the European X-FEL project, the Paul Scherrer Institut (PSI) agreed in taking over responsibility for electron beam stabilization by developing a fast intra bunch train feedback (IBFB) system, which will be tested in its prototype version at the VUV-FEL facility at DESY. The IBFB will make use of the long bunch trains provided by the superconducting drive accelerators of the VUV- as well as the European X-FEL allowing to damp beam motions in a frequency range of a few kHz up to several hundreds of kHz applying modern control algorithms in a feedback loop. The FPGA-based, digital data processing and the low latency time (preferably < 200 ns) permit the elimination of long range (from bunch train to bunch train) and ultra fast (bunch by bunch) repetitive beam movements by adaptive feed forwards. In this paper, we will introduce the IBFB design concept and report on first test measurements with newly designed stripline beam position monitors for the VUV-FEL.
THPCH160	Theoretical Study and Experimental Result of the RF Coupler Prototypes of Spiral 2	simulation, vacuum, coupling, SPIRAL2	3170
	Y. Gómez-Martínez, D. Bondoux, JM. Carretta, J.-M. De Conto, M. Fruneau, A. Garrigue, D. Marchand, R. Micoud, E. Vernay, F. Vezzu LPSC, Grenoble P. Balleyguier CEA, Bruyères-le-Châtel M. Di Giacomo GANIL, Caen
	Spiral 2 is a 40 MeV superconducting linac under construction at GANIL. The RF couplers have to provide a 12 kW CW power to the cavities at 88 MHz. Two solutions corresponding to 2 different technologies have been designed and 2 prototypes have been built. We present the technical proposals and issues as well as the results (manufacturing, test at low and high power, multipacting…) leading to the final choice.
THPLS114	"CAMSHAFT" Bunch Kicker Design for the ALS Storage Ring	kicker, storage-ring, vacuum, feedback	3547
	S. Kwiatkowski, K.M. Baptiste, W. Barry, J. Julian, L. Low, D.W. Plate, G.J. Portmann, D. Robin LBNL, Berkeley, California
	ALS is a 1.9 GeV third generation synchrotron light source that has been operating since 1992 at Lawrence Berkeley National Laboratory. There are two typical modes of operation of the ALS storage ring. In multibunch mode, the ring is filled to a current of 400 mA in 276 consecutive bunches with a single "camshaft" bunch located in the middle of the 52 bucket gap (h=328). Twice each year, ALS operates in "two-bunch" mode for periods of two weeks delivering 20 mA of average beam current in two diametrically opposite bunches to a small group of users requiring light pulses at lower rates. We plan to build a fast kicker system that will supply single bunch light to users during multibunch operation by displacing the orbit of the camshaft bunch at a prescribed frequency (every N turns). Realization of this project will increase ALS beam availability to multibunch users by at least 10%. This paper will describe the hardware design (pulse generator and beam deflection device) and the test results of the prototype kicker unit.
THPLS135	The Study of Errors of ALBA Fixed Stretched Wire Bench	alignment, undulator, insertion-device, insertion	3601
	J. Marcos, J. Campmany, D. Einfeld ALBA, Bellaterra
	The new synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009. The facility includes a laboratory for magnetic measurements laboratory devoted to IDs. The stretched wire measurement technique is widely used to obtain magnetic field integrals. This technique is based upon the displacement of a stretched wire relative to the magnetic structure to be measured. In the most usual configuration, the magnets are kept fixed while the wire is moved. This arrangement is especially well suited for measuring big structures such as full undulators or its jaws. In contrast, in the fixed stretched wire configuration the magnetic structure is moved relative to a stationary pick-up coil with a straight segment. This layout is convenient for the measurement of small units, such as individual magnet blocks or magnetic modules. These measurements allow characterising the inhomogeneities of the building blocks of an undulator. In this paper we present an exhaustive analysis of error sources and tolerance requirements for a particular design of a fixed stretched wire bench made at ALBA, based both in the ESRF, SOLEIL and BESSY previous existing designs.