DIPAC2011 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOOB01	An Aperture Backscatter X-ray Beam Position Monitor at Diamond	photon, polarization, scattering, undulator	6
	C. Bloomer, G. Rehm, C.A. Thomas Diamond, Oxfordshire, United Kingdom
	This paper presents the design and first results of a new XBPM developed at Diamond that images the backscatter from an aperture in the Front End to measure the beam centre of mass. This is of particular interest for monitoring the emission from elliptically polarizing undulators where the profile of the beam varies strongly with change of beam polarization. Traditional four-blade Front End XBPMs struggle to resolve a beam centre of mass for EPUs because of this. We have developed an XBPM that observes the backscattered photons from a copper aperture through a pinhole. This solution is capable of operating with the full white beam, and has been designed to fit into the same physical space as the standard front end XBPMs in use at Diamond. This offers the potential to easily replace traditional XBPMs where beneficial and required.
	Slides MOOB01 [7.211 MB]

MOOB03	Diamond-based Beam Halo Monitor Equipped with RF Fingers for SACLA	wakefield, simulation, electron, radiation	12
	H. Aoyagi, T. Aoki, T. Bizen, K. Fukami, N. Nariyama, S. Suzuki JASRI/SPring-8, Hyogo-ken, Japan Y. Asano, T. Itoga, H. Kitamura, T. Tanaka RIKEN/SPring-8, Hyogo, Japan
	Funding: This work is partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (c) 21604017. The diamond-based beam halo monitor has been developed for SPring-8 Angstrom Compact free electron LAser (SACLA). This monitor is an interlock sensor to protect the undulator magnets against radiation damage. Pulse-mode measurement is adopted to suppress the background noise efficiently. The diamond detectors are dipped into the beam duct in order that the intensity of the beam halo can be measured directly. However, it is important issue to avoid degradation in quality of electron beam for SPring-8 XFEL. We designed new RF fingers with aluminum windows in order to reduce the impedance to the beam. The RF fingers are made of beryllium copper, and having the aluminum windows, which is low-Z material, in front of active areas of the diamond detectors. Therefore, the influence of secondary electrons and bremsstrahlung from the finger material can be suppressed. To evaluate influence on the output signal of the diamond detector by changing the finger material, both the simulation study and the experimental measurement have been carried out. Feasibility tests of this monitor, which is equipped with the RF fingers, have also been demonstrated at the SCSS test accelerator.
	Slides MOOB03 [1.353 MB]

MOPD01	Beam Diagnostics for the NSLS-II Booster	pick-up, booster, betatron, controls	29
	V.V. Smaluk BINP, Novosibirsk, Russia E.A. Bekhtenev, V.P. Cherepanov, G.V. Karpov, V. Kuzminykh, O.I. Meshkov BINP SB RAS, Novosibirsk, Russia I. Pinayev, O. Singh, K. Vetter BNL, Upton, Long Island, New York, USA
	For successful commissioning and effective operation of the projected NSLS-II Booster, a set of beam diagnostic instruments has been designed. Fluorescent screens are used for the Booster commissioning and troubleshooting. Closed orbit is measured using electrostatic BPMs with turn-by-turn capability. The circulating current and beam lifetime are measured using a DC current transformer. The fill pattern is monitored by a fast current transformer. Visible synchrotron radiation is registered for observation of the beam image. Betatron tunes are measured using two pairs of striplines, the first pair is for beam excitation and the second one – for beam response measurement. Design and performance of the Booster beam instrumentation are described.

MOPD14	Calibration of the Electrostatic Beam Position Monitors for VEPP-2000	pick-up, electron, optics, positron	68
	Yu. A. Rogovsky, I. Nesterenko BINP SB RAS, Novosibirsk, Russia
	The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.
	Poster MOPD14 [0.393 MB]

MOPD18	Embedded Collimator Beam Position Monitors	beam-losses, collimation, impedance, proton	80
	C.B. Boccard, A. Bertarelli, A. Dallocchio, M. Gasior, L. Gentini, A.A. Nosych CERN, Geneva, Switzerland
	The LHC collimation system is crucial for safe and reliable operation of proton beams with 350 MJ stored energy. Currently the collimator set-up is performed by observing beam losses when approaching the collimator jaws to the beam. For all 100 LHC movable collimators the procedure may take several hours and since it has to be repeated whenever the beam configuration changes significantly, the collimator setup has an important impact on the overall machine operation efficiency. To reduce the collimator setup time by two orders of magnitude the next generation of the LHC collimators will be equipped with button beam position monitors (BPMs) embedded into the collimator jaws. This paper describes the BPM design and presents prototype results obtained with beam in the CERN-SPS.
	Poster MOPD18 [1.729 MB]

MOPD19	Button BPM Development for the European XFEL	simulation, cryogenics, linac, cavity	83
	D. Lipka, B. Lorbeer, D. Nölle, M. Siemens, S. Vilcins DESY, Hamburg, Germany
	Button beam position monitors will be the main BPM type used to measure the electron beam position at the European XFEL. Two different kinds of buttons are necessary: one type will be installed in the acceleration modules of the cold linac and the other in the warm environment. The electro-magnetic design of the feedthrough for both types of buttons will be discussed. A comparison of the designed and measured RF properties will be presented. In addition to the usual RF properties, also the properties at cryogenic level will play a role. HOM power must not heat up the BPM feedthroughs, in order to keep the cryo load of an overall accelerator module low, and also to prevent damage due to large temperature gradients over the ceramics of the feedthrough. First measurements with beam at FLASH show good agreement of the measured signals with the expectation.

MOPD24	A High-resolution Diode-based Orbit Measurement System – Prototype Results from the LHC	feedback, pick-up, injection, coupling	98
	M. Gasior, J. Olexa, R.J. Steinhagen CERN, Geneva, Switzerland
	The prototype of a high resolution beam position monitor (BPM) electronics based on diode peak detectors was tested with LHC beams. In this technique developed at CERN the short beam pulses from each BPM electrode are converted into slowly varying signals by compensated diode peak detectors. The slow signals can be digitised with a laboratory voltmeter or high resolution ADC. As presented in the paper, this technique allows resolutions in the order of 1 ppm of the BPM aperture to be achieved with a measurement rate in the Hz range. Ongoing developments and future prospects for the technique are also discussed.
	Poster MOPD24 [2.055 MB]

MOPD27	A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI	pick-up, ion, electron, impedance	107
	F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick GSI, Darmstadt, Germany Yu.A. Litvinov MPI-K, Heidelberg, Germany M.S. Sanjari IKF, Frankfurt am Main, Germany J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao IMP, Lanzhou, People's Republic of China
	A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD28	Loss Factor Measurement using Time Correlated Single Photon Counting of Synchrotron Radiation	photon, cavity, storage-ring, synchrotron	110
	G. Rehm, C. Bloomer, C.A. Thomas Diamond, Oxfordshire, United Kingdom
	A method to derive the total loss factor from the variation of SR photon arrival times with bunch charge has been developed. A time correlated single photon counting system is used operationally for fill pattern and bunch purity measurements. By fitting the individual peaks in the photon arrival time histogram, their relative timing can be retrieved with ps resolution and reproducibility. For a measurement of the loss factor, a fill pattern comprising a range of different bunch charges is stored and then their timing relative to the RF buckets is charted against charge. Examples of measurements illustrate the variation of loss factor with RF voltage and change in Insertion Device gap.

MOPD30	Bunch Length Measurement for PETRA III Light Source Storage Ring	synchrotron, ion, extraction, radiation	113
	H.-C. Schröder, A. Affeldt, H.P. Gausepohl, G. Kube, G. Priebe DESY, Hamburg, Germany
	To fulfill the demand for a very high brilliance synchrotron light source, it is required, that the individual particle bunches, used to create the synchrotron light in special undulator sections, do not exceed certain limits in linear dimension and divergence during the storage time. The bunch length measurement in the visible region of the spectrum is the sole system to measure the longitudinal beam parameter needed for a complete description of the behavior of the PETRAIII positron beam. A detailed description of the dipole magnet visible synchrotron light extraction, the light transport and the analysis by means of a Streak Camera System (SCS) in the context of the PETRAIII storage ring is given. The influence of the custom designed apochromatic refractive optics transport line on the time resolution of the bunch length measurement is discussed and values are given. The final time resolution of the whole system transport optics and Streak camera is shown to be not bigger than 4 ps. Several measurements from PETRAIII runs are presented and results of the bunch length measurements are shown. The typical bunch length measured is about 40 ps.
	Poster MOPD30 [6.402 MB]

MOPD33	Pickup Design for a High Resolution Bunch Arrival Time Monitor for FLASH and XFEL	pick-up, simulation, electron, laser	122
	A. Angelovski, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb DESY, Hamburg, Germany J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free Electron Laser in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAM’s) which are part of the optical synchronization system [1-2]. FLASH usually works with bunch charges of 0.2 to 1 nC, but for a variety of future experiments, the system needs to operate with bunch charges in the range of 10 to 20 pC. Below 0.2 nC the sensitivity of such a BAM scales approximately linearly with the bunch charge and therefore the system no longer fulfills the time resolution requirements for these low charges. For the low bunch charge regime operation, the bandwidth has to be increased substantially. This paper shows a new design of a high frequency button pickup that can operate in a frequency band from DC up to 40 GHz. The design criteria of the pickup are the voltage slope steepness at the zero-crossing, the maximum amplitude and the ringing of the picked-up voltage. The performance of the designed model is analyzed for fabrication tolerances and orbit variations. Some manufacturing and practical issues are discussed and solutions are offered for improving the results. A full wave simulation with CST PARTICLE STUDIO is performed in order to prove the concept. [1] F. Loehl et. al.,“A Sub 100 fs Electron Bunch Arrival-time Monitor System for FLASH”, THOBFI01, EPAC 2006 [2] F. Loehl et. al.,“A Sub-50 Femtosecond bunch arrival time monitor system for FLASH”, WEPB15, DIPAC 2007
	Poster MOPD33 [27.661 MB]

MOPD34	Analysis of New Pickup Designs for the FLASH and XFEL Bunch Arrival Time Monitor System	pick-up, simulation, laser, electron	125
	A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb DESY, Hamburg, Germany J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by 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)[1], 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 bunch charges of 10-20 pC. The sensitivity of the measurement system is defined by the slope of the pickup signal at the zero crossing and scales close to linear with the bunch charge. The requirements on the time resolution will no longer be fulfilled when operating at decreased bunch charges. Several designs have been developed in CST PARTICLE STUDIO®, each having an increased bandwidth larger than 40 GHz for meeting the requirements when operating at low bunch charges. Furthermore, new post-processing functions for the automatic evaluation of the signal slope and the ringing in the detected voltage signal have been developed and implemented within the CST software for defining optimization goals of the built-in optimizer for determining free design parameters. Results of the new designs are presented and compared with the current BAM pickup. [1] M.K. Bock et.al., "Recent Developments of the Beam Arrival Time Monitor with Femtosecond Resolution at FLASH", WEOCMH02, IPAC 2010
	Poster MOPD34 [3.112 MB]

MOPD37	Simulations of the Coherent Gap Radiation for the Bunch Length Monitor of FERMI@Elettra	simulation, radiation, resonance, electromagnetic-fields	134
	R. Appio, P. Craievich, M. Ferianis, M. Veronese ELETTRA, Basovizza, Italy
	Non-destructive bunch length measurements after the magnetic compression is performed in Fermi@Elettra via the so-called Bunch Length Monitor (BLM) diagnostics. The BLM system is based on the diffraction radiation from a ceramic gap, captured by three millimeter-waves diodes, and the edge radiation from the last bending magnet of the bunch compressors, captured by a pyrodetector. In this paper we report on the study of the coherent radiation from a gap which we performed both applying the analytical theory and by means of simulations of the radiated electromagnetic field (CST Particle Studio). The study started from a simple gap in vacuum; time and frequency domain results were then investigated and compared with analytical theory. Finally in order to study a more realistic system, we investigated the effect of the dielectric and metallic holed shield used to assure the electric continuity.

MOPD51	Progress with the Scintillation Profile Monitor at COSY	proton, synchrotron, power-supply, target	164
	V. Kamerdzhiev, J. Dietrich, F. Klehr, K. Reimers FZJ, Jülich, Germany
	After successful demonstration measurements with the Scintillation Profile Monitor at COSY, a dedicated vacuum chamber with two vacuum windows and supporting vacuum ports was installed in the COSY synchrotron. The chamber is blackened inside to suppress light reflection. Since residual gas pressure is too low to support reliable profile measurements based on beam induced scintillation, a piezo-electric dosing valve was installed allowing fast injections of defined amount of nitrogen. A 32-channel photomultiplier is used to detect light. Beam profile measurements and first operational experience are reported.

MOPD82	Installation for Measurements of Secondary Emission Yield and Electron Cloud Lifetime in Magnetic Field	electron, cryogenics, cathode, simulation	236
	A.A. Krasnov, V.V. Anashin, V.K. Ovchar, V.V. Smaluk, D.P. Sukhanov BINP SB RAS, Novosibirsk, Russia
	An experimental setup for investigations of electron-surface interaction and electron cloud behavior is under commissioning at BINP. The proposed method provides direct measurements of secondary emission yield and electron clouds lifetime in the presence of strong magnetic field. In principle, the experiments can be performed at cryogenic temperatures. The experimental data will help to figure out the process of reflection of low energy electrons from a metal surface and can be useful for improvement of computer codes developed for simulation of electron clouds behavior in a cold beam pipe of particle accelerators. The structure and performance capabilities of the setup are described, first experimental results are presented.

MOPD83	Performance of the Fast Beam Conditions Monitor BCM1F in the CMS Experiment at the LHC	proton, radiation, monitoring, luminosity	239
	M.E. Castro Carballo DESY Zeuthen, Zeuthen, Germany
	In the CMS detector a series of beam condition monitors were installed and are in operation for measuring radiation doses and preventing possible damages to the detector in case of beam losses. The Fast Beam Condition Monitor, BCM1F, is installed inside the pixel volume close to the beam pipe and it consists of two planes of 4 modules each located 1.8 m away from the IP, on both sides. It uses single-crystal CVD diamond sensors and radiation hard front-end electronics, along with an optical transmission of the signal. It was designed for fast flux monitoring, measuring beam halo and collision products on a bunch by bunch basis. Early in November 2009 the LHC restarted running with beams and since then BCM1F has been recording data from beam halo, beam studies, proton-proton and lead-lead collisions. It is an invaluable tool in everyday CMS operation and, due to the high sensitivity to beam conditions, is providing the so called Background (BKGD) 1 to LHC operators. A characterization of the system on the basis of data collected during LHC operation will be presented.
	Poster MOPD83 [1.449 MB]

MOPD92	Review of Recent Upgrades & Modernizations on Diagnostics in the ESRF Storage Ring and Injector	booster, storage-ring, controls, diagnostics	263
	B. Joly, P. Arnoux, D. Robinson, K.B. Scheidt ESRF, Grenoble, France
	Over the last two years a number of upgrades and modernizations have been implemented on diagnostic tools in both the Injector system and the Storage Ring. Brand new diagnostic tools have also been added. In the Injector, a new Transfer Line current monitor has been installed, as well as four new ¼ λ Striplines equipped with Single-Pass Libera electronics. In the Storage Ring, a new Visible Light Mirror (VLM) system has replaced the original system that had been in place for more than 15 years. Also, the acquisition system for the DC Current Transformers has been upgraded with new hardware. Descriptions and results are presented on the improved reliability, sensitivity and resolution of these systems.

TUPD12	The LHC Beam Position System: Performance during 2010 and Outlook for 2011	pick-up, feedback, closed-orbit, injection	323
	E. Calvo Giraldo, J.L. Gonzalez, L.K. Jensen, O.R. Jones, T. Lefèvre, J.-J. Savioz, R.J. Steinhagen, J. Wenninger CERN, Geneva, Switzerland
	This paper presents the performance of the LHC Beam Position System during 2010. The system proved to meet most specifications, was highly reliable and continuously provided 25Hz real-time orbit data with micron level resolution to the automatic global orbit feedback system. However, several issues were observed and they will be discussed in detail, such as the dependence on bunch intensity and the effect of surface electronics temperature variations on the measured position.

TUPD20	Pre-amplifier Impedance Matching for Cryogenic BPMs	cryogenics, impedance, synchrotron, quadrupole	347
	P. Kowina, M. Freimuth, K. Gütlich, W. Kaufmann, H. Rödl, J. Wießmann GSI, Darmstadt, Germany N. Sobel, F. Völklein Hochschule RheinMain, Wiesbaden, Germany
	Beam Position Monitors (BPMs) for the FAIR fast-ramped super conducting synchrotron SIS-100 will be installed inside the cryostats of quadrupole magnets. This contribution focuses on the coupling path between BPM electrodes and low noise amplifiers installed outside the cryostat. Matching transformers (MT) meet well the requirements of reflection free signal transfer through the relative long lines without loading the capacitive BPM by 50 Ohm. Different transformers based on toroidal cores made out of Vitroperm-500F nanocrystalline were tested. The form of windings and circuit geometry were optimized to improve linearity allow for resonance-free transmission over a required frequency range from 0.1 MHz to 80 MHz. The MTs have to be balanced pair wise within 0.1 dB and the geometry of windings has to be mechanically stabilized using e.g. epoxy resin. A choice of different epoxy types and their suitability for cryogenic operation was tested in liquid Nitrogen and liquid Helium.
	Poster TUPD20 [0.655 MB]

TUPD24	Design Status of Beam Position Monitors for the FAIR Proton Linac	linac, proton, simulation, cavity	356
	C.S. Simon, F. Senée CEA/DSM/IRFU, France G. Clemente, P. Forck, W. Kaufmann, P. Kowina GSI, Darmstadt, Germany
	Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

TUPD25	Design of Magnetic BPM and Error Corrections	electron, simulation, shielding, instrumentation	359
	M. Shafiee, E. Ebrahimi, S.A.H. Feghhi Shahid Beheshti University, Evin, Tehran, Iran
	For beam position monitoring (BPM) purposes, two prominent approaches as a physical effect have been applied including electrostatic and magnetic. In electrostatic types, secondary emission from the electrodes can be a problem when strong beam loss occurs, in such a situation, a magnetic BPM may be chosen. For this purpose we made a magnetic BPM including a square shape of ferromagnetic core with winding on each side. In this case study we used it for detecting the position of wire which is including a pulsed current (as an electron bunch) produced by a PROTEK G305 pulse generator. A Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of magnetic BPM. Measurement results have been compared with simulation using CST software and performed error corrections which are presented, with this regard we could measure the wire position with high resolution furthermore we deduced the wire position hasn’t linear relation with induced voltage and needs more physical and mathematical analyzing. This way propose us that we can use magnetic BPMs in this approach and calibrate them before installing on accelerators.
	Poster TUPD25 [0.120 MB]

TUPD32	THz Radiation Diagnostics for Monitoring the Bunch Compression at the SwissFEL Injector Test Facility	radiation, electron, simulation, FEL	374
	C. Gerth, B. Schmidt, S. Wesch DESY, Hamburg, Germany R. Ischebeck, G.L. Orlandi, P. Peier, V. Schlott PSI, Villigen, Switzerland
	At the SwissFEL Injector Test Facility, installation of a magnetic chicane for longitudinal bunch compression is foreseen for the first half of 2011. Bunch compression will be accomplished by operating two S-band accelerating structures on-crest and two S-band structures at off-crest RF phases. An X-band structure for the linearization of the longitudinal phase space will be installed at a later stage. The detection of coherent synchrotron radiation or coherent diffraction radiation in the THz range can be used to monitor the bunch compression process and stabilize the RF phases by a beam-based feedback. In this paper, we study the source characteristics of the edge radiation emitted at the 4th dipole of the bunch compressor as well as the diffraction radiation generated by a metallic foil with a hole. Particle tracking simulations were used to model the bunch compression process for different operation modes. The performance of a bunch compression monitor consisting of focusing mirrors and band pass filters has been evaluated by simulating the THz radiation transport of the optical components.

TUPD33	Coherent Resonant Diffraction Radiation from Inclined Grating as a Tool for Bunch Length Diagnostics	radiation, diagnostics, electron, synchrotron	377
	L.G. Sukhikh, G. Kube DESY, Hamburg, Germany A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia V. Schlott PSI, Villigen, Switzerland
	There exists considerable interest in studying new types of non-invasive bunch length diagnostics for sub-picosecond bunches. In this context coherent Smith-Purcell radiation (CSPR) is a good candidate because the use of grating causes wavelength dispersive radiation emission, i.e. a CSPR based monitor does not require any additional spectrometer. In contrast to existing CSPR monitors a new scheme is proposed with two detectors placed at fixed positions, and a wavelength scan is performed by scanning the tilt angle between grating surface and beam axis. In this scheme the information of both detectors, positioned opposite to each other and perpendicular to the beam axis, can be combined by taking the intensity ratio of the signals from both detectors. The advantage of such diagnostics scheme is that one has not to rely on absolute values of the radiation yield, avoiding the need to know the sensitivity of each detector with high accuracy. In contrast to CSPR which is emitted from a grating oriented parallel to the beam, the effect is termed coherent resonant diffraction radiation when the grating is tilted. In the report we present simulation results and detailed experimental plan.

TUPD39	Observation of Synchrotron Radiation Using Low Noise Block (LNB) at ANKA	radiation, synchrotron, storage-ring, synchrotron-radiation	389
	V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale KIT, Karlsruhe, Germany F. Caspers CERN, Geneva, Switzerland
	Funding: Work supported by the Initiative and Networking Fund of the Helmholtz Association under contact number VH-NG-320 Generally Coherent Synchrotron Radiation (CSR) is emitted for wavelengths longer than or equal the bunch length, so for CSR in the THz-range short bunches are required. There are two types of detectors in this range of the spectrum: slow detectors like a golay cell or pyrometric detectors (used for e.g. imaging, spectroscopy) and fast detectors like superconducting bolometer detector systems and Schottky Barrier diodes (used for e.g. the investigation of dynamic processes in accelerator physics). The hot electron bolometer (HEB) detector system is a member of second group. It is very fast and has broad spectral characteristics, but unfortunately very expensive and have to be cooled using liquid helium. If the broad spectral response is not important, it will be suitably to use a Schottky Barrier diode instead. These detectors are massively cheaper but also slower. As an alternative to a Schottky diode a LNB (Low Noise Block) can be also used. It is usually used in standard TV-SAT-receivers. Due to mass production LNBs became very cheap, moreover they are optimized to detect very low intensity "noise-like" signals. In this paper we present our experience with a LNB at ANKA.

TUPD42	Design and Experiences with the Beam Condition Monitor as Protection System in the CMS Experiment of the LHC	background, monitoring, beam-losses, radiation	398
	M. Guthoff CERN, Geneva, Switzerland
	The Beam Condition Monitor (BCM) is used as protection system. In order to prevent damage to the pixel and tracker detectors it can trigger a beam dump when extremely high beam losses occur. The system consists of BCM1L with 4 diamonds per side at 1.8m away from the interaction point and BCM2 with 4 inner and 8 outer diamonds per side at 14.4m away from the interaction point. As detector material poly-crystalline CVD diamonds are used. The readout electronics is identical to the Beam Loss Monitor (BLM) system of the LHC. With cross calibration measurements a direct comparison between the BLM and the BCM systems is possible. The BCM system is therefore a transparent extension of the BLM system into the CMS cavern. The BCM2 system has been active in the beam abort system since the beginning of collisions at the LHC. Design and performance of the system during the run of the LHC so far will be presented. *on behalf of the CMS BRM group.
	Poster TUPD42 [0.736 MB]

TUPD52	First Measurements with the Test Stand for Optical Beam Tomography	ion, luminosity, beam-transport, photon	422
	C. Wagner, O. Meusel, U. Ratzinger, H. Reichau IAP, Frankfurt am Main, Germany
	A test stand for optical beam tomography was developed. As a new non-destructive beam-diagnostic system for high current ion beams, the test stand will be installed in the low energy beam transport section (LEBT) of the Frankfurt Neutron Source (FRANZ) behind the chopper system. The test stand consists of a rotatable vacuum chamber with a mounted CCD camera. The maximum rotation angle amounts to 270°. In a first phase the optical beam profile measurement and 3D density reconstruction is tested with a time independent 10 keV He beam. The measurements and performance of data processing algorithms are compared with the beam transport simulations. In a later phase the performance with time dependent beams (120 keV, 200 mA) at a repetition rate of 250 kHz and a duty cycle of 2.5% has to be evaluated. An overview of the first phase results is shown.
	Poster TUPD52 [13.501 MB]

TUPD55	Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN	instrumentation, impedance, dipole, electron	431
	D. Egger EPFL, Lausanne, Switzerland A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca CERN, Geneva, Switzerland
	The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.
	Poster TUPD55 [0.959 MB]

TUPD58	Non-interceptive Profile Measurements using an Optical-based Tomography Technique	diagnostics, laser, ion, simulation	437
	C.M. Mateo, G. Adroit, G. Ferrand, A. France, R. Gobin, S. Nyckees, Y. Sauce, F. Senée, O. Tuske CEA/IRFU, Gif-sur-Yvette, France
	Funding: This work is supported by the DITANET Marie Curie European network Most of the charged particle beam shapes do not possess symmetry. In such cases, diagnostic measurement obtained in one direction is not enough to reconstruct the spatial distribution of the beam. The use of intense beams which demands for non-interceptive diagnostic devices posed another challenge in measuring the beam’s spatial distribution. At CEA Saclay and within the DITANET framework, the use of tomography combined with optical diagnostics to develop a non-interceptive transverse profile monitor is under development. This profile monitor is presently tested on the BETSI test bench. In this contribution, a tomography algorithm suited for beam profile measurements is presented. This algorithm is based on the formulation of iterative Algebraic Reconstruction Technique (ART) problem and the Maximum-Likelihood Expectation Maximization (MLEM) for the iteration step. The algorithm is optimized within the limit of using 6 projections only. Several beam shapes are generated and then reconstructed computationally. Actual measurements in the BETSI test bench are also done to verify the tomographic reconstruction process.

TUPD63	Gas Electron Multipliers for the Antiproton Decelerator	electron, antiproton, cathode, high-voltage	449
	S.C. Duarte Pinto, O.R. Jones, L. Ropelewski, J. Spanggaard, G. Tranquille CERN, Geneva, Switzerland
	The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light (~0.4% X₀), and measures horizontal and vertical profiles directly in one plane. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPCs) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another 3 detectors now installed in the ASACUSA beam line. This paper will provide a detailed description of the detector and discuss the initial results obtained.

TUPD64	Test Measurements of a 20 m/s Carbon Wire Beam Scanner	controls, simulation, feedback, acceleration	452
	M. Koujili, J. De Freitas, B. Dehning, J. Emery, J.F. Herranz Alvarez, D. Ramos, M. Sapinski CERN, Geneva, Switzerland Y. Ait Amira UFC, Besançon, France A. Djerdir UTBM, Belfort, France
	This paper presents the design of the actuator for the fast and high accuracy Wire Scanner system. The actuator consists of a rotary brush-less synchronous motor with the permanent magnet rotor installed inside the vacuum chamber and the stator installed outside. The fork, permanent magnet rotor and two angular position sensors are mounted on the same axis and located inside the beam vacuum chamber. The system has to resist a bake-out temperature of 200°C and ionizing radiation up to tenths of kGy/year. Maximum wire travelling speed of 20 m/s and a position measurement accuracy of 4 μm is required. Therefore, the system must avoid generating vibration and electromagnetic interference. A digital feedback controller will allow maximum flexibility for the loop parameters and feeds the 3-phase linear power driver. The performance of the presented design is investigated through simulations and experimental tests.

TUPD65	Four-Dimensional Transverse Emittance Measurement Unit for High Intensity Ion Beams	emittance, ion, rfq, background	455
	S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.R. Lu, Z.X. Yuan, J. Zhao PKU/IHIP, Beijing, People's Republic of China H.T. Ren Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China An X-Y coplaner High Intensity Beam Emittance Measurement Unit named as HIBEMU-4 has been developed recently to measure the emmitance of 2 MeV/40mA D⁺ beam at the RFQ exit of PeKing University Neutron Imaging FaciliTY (PKUNIFTY). HIBEMU-4 is based on the slit-wire method, and has two groups of slits in the orthogonal directions. Equipped with user-oriented software, it is able to provide results as root-mean-square(rms) emittance, boundary emittance, Twiss-parameters and phase diagram. In this paper we will mainly discuss the strengths and limitations of HIBEMU-4 at the aspects of mechanical designing and data processing method. In addition the testing of HIBEMU-4 on 1MeV O+ beam as well as 2 MeV/40mA D⁺ is closely presented, which shows HIBEMU-4 is competent in high intensity beam (HIB) emmitance measurements.

TUPD69	Operational Experience and Improvements of the LHC Beam Current Transformers	feedback, luminosity, proton, diagnostics	467
	P. Odier, D. Belohrad, J-J. Gras, M. Ludwig CERN, Geneva, Switzerland
	During the 2010 run the LHC continuously improved its performance. In particular the bunch charge and number of bunches were significantly increased, which revealed certain limitations of the LHC beam current transformers. The DC current transformers (DCCT), used to measure the circulating beam current, exhibited saturation related to bunch intensity, the number of batches in the machine and their spacing. Two major issues were also discovered on the fast beam current transformers (FBCT) used to measure the individual bunch charges: discrepancies in the measured intensities when compared to the DCCTs measurements and a bunch length dependence on the measured intensity. Further analysis showed that both problems are linked to the beam position dependence of the signal acquired from the toroids used in the FBCTs. This paper presents the observed issues, discusses possible solutions and reports on the results from modification made for the 2011 run.

TUPD93	Diagnostics of RF Breakdowns in High-Gradient Accelerating Structures	collider, plasma, electron, linear-collider	527
	A. Palaia Uppsala University, Uppsala, Sweden V.A. Dolgashev, J.R. Lewandowski, S.P. Weathersby SLAC, Menlo Park, California, USA
	Within the framework of the research on high-gradient accelerating structures for future linear colliders, diagnostics of radio-frequency (RF) breakdowns is of great importance to support the understanding of the vacuum breakdown process. Measurements of RF and electron and ion currents emitted during and after a breakdown can be used to calculate the properties of any objects responsible for such power reflection and charge emission. Possible breakdown models, breakdown localization and a time-scale of the process are here discussed and compared to dedicated measurements. First results are presented.
	Poster TUPD93 [7.029 MB]

WEOC01	Beam Charge Measurements	coupling, impedance, pick-up, linac	564
	D. Belohrad CERN, Geneva, Switzerland
	The measurement of beam charge is fundamental to all particle accelerators. There exist many methods to achieve this, which can broadly be classified into two categories: intercepting measurements, which are destructive for the beam and result in absorption of a significant amount of energy; non-intercepting measurements using electric or magnetic field coupling. In both categories one can find instruments that process the beam signals with high dynamic range, both in amplitude and time. The aim of this article is to present the current state of beam charge measurement technology. Various measurement methods will be described with their uses, advantages, and achievable resolution and accuracy discussed. The technological problems related to their fabrication will also be addressed.
	Slides WEOC01 [5.738 MB]

Paper

Title

Other Keywords

Page

MOOB01

An Aperture Backscatter X-ray Beam Position Monitor at Diamond

photon, polarization, scattering, undulator

6

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

This paper presents the design and first results of a new XBPM developed at Diamond that images the backscatter from an aperture in the Front End to measure the beam centre of mass. This is of particular interest for monitoring the emission from elliptically polarizing undulators where the profile of the beam varies strongly with change of beam polarization. Traditional four-blade Front End XBPMs struggle to resolve a beam centre of mass for EPUs because of this. We have developed an XBPM that observes the backscattered photons from a copper aperture through a pinhole. This solution is capable of operating with the full white beam, and has been designed to fit into the same physical space as the standard front end XBPMs in use at Diamond. This offers the potential to easily replace traditional XBPMs where beneficial and required.

Slides MOOB01 [7.211 MB]

MOOB03

Diamond-based Beam Halo Monitor Equipped with RF Fingers for SACLA

wakefield, simulation, electron, radiation

12

H. Aoyagi, T. Aoki, T. Bizen, K. Fukami, N. Nariyama, S. Suzuki
JASRI/SPring-8, Hyogo-ken, Japan
Y. Asano, T. Itoga, H. Kitamura, T. Tanaka
RIKEN/SPring-8, Hyogo, Japan

Funding: This work is partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (c) 21604017.
The diamond-based beam halo monitor has been developed for SPring-8 Angstrom Compact free electron LAser (SACLA). This monitor is an interlock sensor to protect the undulator magnets against radiation damage. Pulse-mode measurement is adopted to suppress the background noise efficiently. The diamond detectors are dipped into the beam duct in order that the intensity of the beam halo can be measured directly. However, it is important issue to avoid degradation in quality of electron beam for SPring-8 XFEL. We designed new RF fingers with aluminum windows in order to reduce the impedance to the beam. The RF fingers are made of beryllium copper, and having the aluminum windows, which is low-Z material, in front of active areas of the diamond detectors. Therefore, the influence of secondary electrons and bremsstrahlung from the finger material can be suppressed. To evaluate influence on the output signal of the diamond detector by changing the finger material, both the simulation study and the experimental measurement have been carried out. Feasibility tests of this monitor, which is equipped with the RF fingers, have also been demonstrated at the SCSS test accelerator.

Slides MOOB03 [1.353 MB]

MOPD01

Beam Diagnostics for the NSLS-II Booster

pick-up, booster, betatron, controls

29

V.V. Smaluk
BINP, Novosibirsk, Russia
E.A. Bekhtenev, V.P. Cherepanov, G.V. Karpov, V. Kuzminykh, O.I. Meshkov
BINP SB RAS, Novosibirsk, Russia
I. Pinayev, O. Singh, K. Vetter
BNL, Upton, Long Island, New York, USA

For successful commissioning and effective operation of the projected NSLS-II Booster, a set of beam diagnostic instruments has been designed. Fluorescent screens are used for the Booster commissioning and troubleshooting. Closed orbit is measured using electrostatic BPMs with turn-by-turn capability. The circulating current and beam lifetime are measured using a DC current transformer. The fill pattern is monitored by a fast current transformer. Visible synchrotron radiation is registered for observation of the beam image. Betatron tunes are measured using two pairs of striplines, the first pair is for beam excitation and the second one – for beam response measurement. Design and performance of the Booster beam instrumentation are described.

MOPD14

Calibration of the Electrostatic Beam Position Monitors for VEPP-2000

pick-up, electron, optics, positron

68

Yu. A. Rogovsky, I. Nesterenko
BINP SB RAS, Novosibirsk, Russia

The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.

Poster MOPD14 [0.393 MB]

MOPD18

Embedded Collimator Beam Position Monitors

beam-losses, collimation, impedance, proton

80

C.B. Boccard, A. Bertarelli, A. Dallocchio, M. Gasior, L. Gentini, A.A. Nosych
CERN, Geneva, Switzerland

The LHC collimation system is crucial for safe and reliable operation of proton beams with 350 MJ stored energy. Currently the collimator set-up is performed by observing beam losses when approaching the collimator jaws to the beam. For all 100 LHC movable collimators the procedure may take several hours and since it has to be repeated whenever the beam configuration changes significantly, the collimator setup has an important impact on the overall machine operation efficiency. To reduce the collimator setup time by two orders of magnitude the next generation of the LHC collimators will be equipped with button beam position monitors (BPMs) embedded into the collimator jaws. This paper describes the BPM design and presents prototype results obtained with beam in the CERN-SPS.

Poster MOPD18 [1.729 MB]

MOPD19

Button BPM Development for the European XFEL

simulation, cryogenics, linac, cavity

83

D. Lipka, B. Lorbeer, D. Nölle, M. Siemens, S. Vilcins
DESY, Hamburg, Germany

Button beam position monitors will be the main BPM type used to measure the electron beam position at the European XFEL. Two different kinds of buttons are necessary: one type will be installed in the acceleration modules of the cold linac and the other in the warm environment. The electro-magnetic design of the feedthrough for both types of buttons will be discussed. A comparison of the designed and measured RF properties will be presented. In addition to the usual RF properties, also the properties at cryogenic level will play a role. HOM power must not heat up the BPM feedthroughs, in order to keep the cryo load of an overall accelerator module low, and also to prevent damage due to large temperature gradients over the ceramics of the feedthrough. First measurements with beam at FLASH show good agreement of the measured signals with the expectation.

MOPD24

A High-resolution Diode-based Orbit Measurement System – Prototype Results from the LHC

feedback, pick-up, injection, coupling

98

M. Gasior, J. Olexa, R.J. Steinhagen
CERN, Geneva, Switzerland

The prototype of a high resolution beam position monitor (BPM) electronics based on diode peak detectors was tested with LHC beams. In this technique developed at CERN the short beam pulses from each BPM electrode are converted into slowly varying signals by compensated diode peak detectors. The slow signals can be digitised with a laboratory voltmeter or high resolution ADC. As presented in the paper, this technique allows resolutions in the order of 1 ppm of the BPM aperture to be achieved with a measurement rate in the Hz range. Ongoing developments and future prospects for the technique are also discussed.

Poster MOPD24 [2.055 MB]

MOPD27

A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI

pick-up, ion, electron, impedance

107

F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick
GSI, Darmstadt, Germany
Yu.A. Litvinov
MPI-K, Heidelberg, Germany
M.S. Sanjari
IKF, Frankfurt am Main, Germany
J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao
IMP, Lanzhou, People's Republic of China

A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD28

Loss Factor Measurement using Time Correlated Single Photon Counting of Synchrotron Radiation

photon, cavity, storage-ring, synchrotron

110

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

A method to derive the total loss factor from the variation of SR photon arrival times with bunch charge has been developed. A time correlated single photon counting system is used operationally for fill pattern and bunch purity measurements. By fitting the individual peaks in the photon arrival time histogram, their relative timing can be retrieved with ps resolution and reproducibility. For a measurement of the loss factor, a fill pattern comprising a range of different bunch charges is stored and then their timing relative to the RF buckets is charted against charge. Examples of measurements illustrate the variation of loss factor with RF voltage and change in Insertion Device gap.

MOPD30

Bunch Length Measurement for PETRA III Light Source Storage Ring

synchrotron, ion, extraction, radiation

113

H.-C. Schröder, A. Affeldt, H.P. Gausepohl, G. Kube, G. Priebe
DESY, Hamburg, Germany

To fulfill the demand for a very high brilliance synchrotron light source, it is required, that the individual particle bunches, used to create the synchrotron light in special undulator sections, do not exceed certain limits in linear dimension and divergence during the storage time. The bunch length measurement in the visible region of the spectrum is the sole system to measure the longitudinal beam parameter needed for a complete description of the behavior of the PETRAIII positron beam. A detailed description of the dipole magnet visible synchrotron light extraction, the light transport and the analysis by means of a Streak Camera System (SCS) in the context of the PETRAIII storage ring is given. The influence of the custom designed apochromatic refractive optics transport line on the time resolution of the bunch length measurement is discussed and values are given. The final time resolution of the whole system transport optics and Streak camera is shown to be not bigger than 4 ps. Several measurements from PETRAIII runs are presented and results of the bunch length measurements are shown. The typical bunch length measured is about 40 ps.

Poster MOPD30 [6.402 MB]

MOPD33

Pickup Design for a High Resolution Bunch Arrival Time Monitor for FLASH and XFEL

pick-up, simulation, electron, laser

122

A. Angelovski, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb
DESY, Hamburg, Germany
J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Electron Laser in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAM’s) which are part of the optical synchronization system [1-2]. FLASH usually works with bunch charges of 0.2 to 1 nC, but for a variety of future experiments, the system needs to operate with bunch charges in the range of 10 to 20 pC. Below 0.2 nC the sensitivity of such a BAM scales approximately linearly with the bunch charge and therefore the system no longer fulfills the time resolution requirements for these low charges. For the low bunch charge regime operation, the bandwidth has to be increased substantially. This paper shows a new design of a high frequency button pickup that can operate in a frequency band from DC up to 40 GHz. The design criteria of the pickup are the voltage slope steepness at the zero-crossing, the maximum amplitude and the ringing of the picked-up voltage. The performance of the designed model is analyzed for fabrication tolerances and orbit variations. Some manufacturing and practical issues are discussed and solutions are offered for improving the results. A full wave simulation with CST PARTICLE STUDIO is performed in order to prove the concept.
[1] F. Loehl et. al.,“A Sub 100 fs Electron Bunch Arrival-time Monitor System for FLASH”, THOBFI01, EPAC 2006
[2] F. Loehl et. al.,“A Sub-50 Femtosecond bunch arrival time monitor system for FLASH”, WEPB15, DIPAC 2007

Poster MOPD33 [27.661 MB]

MOPD34

Analysis of New Pickup Designs for the FLASH and XFEL Bunch Arrival Time Monitor System

pick-up, simulation, laser, electron

125

A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb
DESY, Hamburg, Germany
J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by 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)[1], 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 bunch charges of 10-20 pC. The sensitivity of the measurement system is defined by the slope of the pickup signal at the zero crossing and scales close to linear with the bunch charge. The requirements on the time resolution will no longer be fulfilled when operating at decreased bunch charges. Several designs have been developed in CST PARTICLE STUDIO®, each having an increased bandwidth larger than 40 GHz for meeting the requirements when operating at low bunch charges. Furthermore, new post-processing functions for the automatic evaluation of the signal slope and the ringing in the detected voltage signal have been developed and implemented within the CST software for defining optimization goals of the built-in optimizer for determining free design parameters. Results of the new designs are presented and compared with the current BAM pickup.
[1] M.K. Bock et.al., "Recent Developments of the Beam Arrival Time Monitor with Femtosecond Resolution at FLASH", WEOCMH02, IPAC 2010

Poster MOPD34 [3.112 MB]

MOPD37

Simulations of the Coherent Gap Radiation for the Bunch Length Monitor of FERMI@Elettra

simulation, radiation, resonance, electromagnetic-fields

134

R. Appio, P. Craievich, M. Ferianis, M. Veronese
ELETTRA, Basovizza, Italy

Non-destructive bunch length measurements after the magnetic compression is performed in Fermi@Elettra via the so-called Bunch Length Monitor (BLM) diagnostics. The BLM system is based on the diffraction radiation from a ceramic gap, captured by three millimeter-waves diodes, and the edge radiation from the last bending magnet of the bunch compressors, captured by a pyrodetector. In this paper we report on the study of the coherent radiation from a gap which we performed both applying the analytical theory and by means of simulations of the radiated electromagnetic field (CST Particle Studio). The study started from a simple gap in vacuum; time and frequency domain results were then investigated and compared with analytical theory. Finally in order to study a more realistic system, we investigated the effect of the dielectric and metallic holed shield used to assure the electric continuity.

MOPD51

Progress with the Scintillation Profile Monitor at COSY

proton, synchrotron, power-supply, target

164

V. Kamerdzhiev, J. Dietrich, F. Klehr, K. Reimers
FZJ, Jülich, Germany

After successful demonstration measurements with the Scintillation Profile Monitor at COSY, a dedicated vacuum chamber with two vacuum windows and supporting vacuum ports was installed in the COSY synchrotron. The chamber is blackened inside to suppress light reflection. Since residual gas pressure is too low to support reliable profile measurements based on beam induced scintillation, a piezo-electric dosing valve was installed allowing fast injections of defined amount of nitrogen. A 32-channel photomultiplier is used to detect light. Beam profile measurements and first operational experience are reported.

MOPD82

Installation for Measurements of Secondary Emission Yield and Electron Cloud Lifetime in Magnetic Field

electron, cryogenics, cathode, simulation

236

A.A. Krasnov, V.V. Anashin, V.K. Ovchar, V.V. Smaluk, D.P. Sukhanov
BINP SB RAS, Novosibirsk, Russia

An experimental setup for investigations of electron-surface interaction and electron cloud behavior is under commissioning at BINP. The proposed method provides direct measurements of secondary emission yield and electron clouds lifetime in the presence of strong magnetic field. In principle, the experiments can be performed at cryogenic temperatures. The experimental data will help to figure out the process of reflection of low energy electrons from a metal surface and can be useful for improvement of computer codes developed for simulation of electron clouds behavior in a cold beam pipe of particle accelerators. The structure and performance capabilities of the setup are described, first experimental results are presented.

MOPD83

Performance of the Fast Beam Conditions Monitor BCM1F in the CMS Experiment at the LHC

proton, radiation, monitoring, luminosity

239

M.E. Castro Carballo
DESY Zeuthen, Zeuthen, Germany

In the CMS detector a series of beam condition monitors were installed and are in operation for measuring radiation doses and preventing possible damages to the detector in case of beam losses. The Fast Beam Condition Monitor, BCM1F, is installed inside the pixel volume close to the beam pipe and it consists of two planes of 4 modules each located 1.8 m away from the IP, on both sides. It uses single-crystal CVD diamond sensors and radiation hard front-end electronics, along with an optical transmission of the signal. It was designed for fast flux monitoring, measuring beam halo and collision products on a bunch by bunch basis. Early in November 2009 the LHC restarted running with beams and since then BCM1F has been recording data from beam halo, beam studies, proton-proton and lead-lead collisions. It is an invaluable tool in everyday CMS operation and, due to the high sensitivity to beam conditions, is providing the so called Background (BKGD) 1 to LHC operators. A characterization of the system on the basis of data collected during LHC operation will be presented.

Poster MOPD83 [1.449 MB]

MOPD92

Review of Recent Upgrades & Modernizations on Diagnostics in the ESRF Storage Ring and Injector

booster, storage-ring, controls, diagnostics

263

B. Joly, P. Arnoux, D. Robinson, K.B. Scheidt
ESRF, Grenoble, France

Over the last two years a number of upgrades and modernizations have been implemented on diagnostic tools in both the Injector system and the Storage Ring. Brand new diagnostic tools have also been added. In the Injector, a new Transfer Line current monitor has been installed, as well as four new ¼ λ Striplines equipped with Single-Pass Libera electronics. In the Storage Ring, a new Visible Light Mirror (VLM) system has replaced the original system that had been in place for more than 15 years. Also, the acquisition system for the DC Current Transformers has been upgraded with new hardware. Descriptions and results are presented on the improved reliability, sensitivity and resolution of these systems.

TUPD12

The LHC Beam Position System: Performance during 2010 and Outlook for 2011

pick-up, feedback, closed-orbit, injection

323

E. Calvo Giraldo, J.L. Gonzalez, L.K. Jensen, O.R. Jones, T. Lefèvre, J.-J. Savioz, R.J. Steinhagen, J. Wenninger
CERN, Geneva, Switzerland

This paper presents the performance of the LHC Beam Position System during 2010. The system proved to meet most specifications, was highly reliable and continuously provided 25Hz real-time orbit data with micron level resolution to the automatic global orbit feedback system. However, several issues were observed and they will be discussed in detail, such as the dependence on bunch intensity and the effect of surface electronics temperature variations on the measured position.

TUPD20

Pre-amplifier Impedance Matching for Cryogenic BPMs

cryogenics, impedance, synchrotron, quadrupole

347

P. Kowina, M. Freimuth, K. Gütlich, W. Kaufmann, H. Rödl, J. Wießmann
GSI, Darmstadt, Germany
N. Sobel, F. Völklein
Hochschule RheinMain, Wiesbaden, Germany

Beam Position Monitors (BPMs) for the FAIR fast-ramped super conducting synchrotron SIS-100 will be installed inside the cryostats of quadrupole magnets. This contribution focuses on the coupling path between BPM electrodes and low noise amplifiers installed outside the cryostat. Matching transformers (MT) meet well the requirements of reflection free signal transfer through the relative long lines without loading the capacitive BPM by 50 Ohm. Different transformers based on toroidal cores made out of Vitroperm-500F nanocrystalline were tested. The form of windings and circuit geometry were optimized to improve linearity allow for resonance-free transmission over a required frequency range from 0.1 MHz to 80 MHz. The MTs have to be balanced pair wise within 0.1 dB and the geometry of windings has to be mechanically stabilized using e.g. epoxy resin. A choice of different epoxy types and their suitability for cryogenic operation was tested in liquid Nitrogen and liquid Helium.

Poster TUPD20 [0.655 MB]

TUPD24

Design Status of Beam Position Monitors for the FAIR Proton Linac

linac, proton, simulation, cavity

356

C.S. Simon, F. Senée
CEA/DSM/IRFU, France
G. Clemente, P. Forck, W. Kaufmann, P. Kowina
GSI, Darmstadt, Germany

Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

TUPD25

Design of Magnetic BPM and Error Corrections

electron, simulation, shielding, instrumentation

359

M. Shafiee, E. Ebrahimi, S.A.H. Feghhi
Shahid Beheshti University, Evin, Tehran, Iran

For beam position monitoring (BPM) purposes, two prominent approaches as a physical effect have been applied including electrostatic and magnetic. In electrostatic types, secondary emission from the electrodes can be a problem when strong beam loss occurs, in such a situation, a magnetic BPM may be chosen. For this purpose we made a magnetic BPM including a square shape of ferromagnetic core with winding on each side. In this case study we used it for detecting the position of wire which is including a pulsed current (as an electron bunch) produced by a PROTEK G305 pulse generator. A Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of magnetic BPM. Measurement results have been compared with simulation using CST software and performed error corrections which are presented, with this regard we could measure the wire position with high resolution furthermore we deduced the wire position hasn’t linear relation with induced voltage and needs more physical and mathematical analyzing. This way propose us that we can use magnetic BPMs in this approach and calibrate them before installing on accelerators.

Poster TUPD25 [0.120 MB]

TUPD32

THz Radiation Diagnostics for Monitoring the Bunch Compression at the SwissFEL Injector Test Facility

radiation, electron, simulation, FEL

374

C. Gerth, B. Schmidt, S. Wesch
DESY, Hamburg, Germany
R. Ischebeck, G.L. Orlandi, P. Peier, V. Schlott
PSI, Villigen, Switzerland

At the SwissFEL Injector Test Facility, installation of a magnetic chicane for longitudinal bunch compression is foreseen for the first half of 2011. Bunch compression will be accomplished by operating two S-band accelerating structures on-crest and two S-band structures at off-crest RF phases. An X-band structure for the linearization of the longitudinal phase space will be installed at a later stage. The detection of coherent synchrotron radiation or coherent diffraction radiation in the THz range can be used to monitor the bunch compression process and stabilize the RF phases by a beam-based feedback. In this paper, we study the source characteristics of the edge radiation emitted at the 4th dipole of the bunch compressor as well as the diffraction radiation generated by a metallic foil with a hole. Particle tracking simulations were used to model the bunch compression process for different operation modes. The performance of a bunch compression monitor consisting of focusing mirrors and band pass filters has been evaluated by simulating the THz radiation transport of the optical components.

TUPD33

Coherent Resonant Diffraction Radiation from Inclined Grating as a Tool for Bunch Length Diagnostics

radiation, diagnostics, electron, synchrotron

377

L.G. Sukhikh, G. Kube
DESY, Hamburg, Germany
A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia
V. Schlott
PSI, Villigen, Switzerland

There exists considerable interest in studying new types of non-invasive bunch length diagnostics for sub-picosecond bunches. In this context coherent Smith-Purcell radiation (CSPR) is a good candidate because the use of grating causes wavelength dispersive radiation emission, i.e. a CSPR based monitor does not require any additional spectrometer. In contrast to existing CSPR monitors a new scheme is proposed with two detectors placed at fixed positions, and a wavelength scan is performed by scanning the tilt angle between grating surface and beam axis. In this scheme the information of both detectors, positioned opposite to each other and perpendicular to the beam axis, can be combined by taking the intensity ratio of the signals from both detectors. The advantage of such diagnostics scheme is that one has not to rely on absolute values of the radiation yield, avoiding the need to know the sensitivity of each detector with high accuracy. In contrast to CSPR which is emitted from a grating oriented parallel to the beam, the effect is termed coherent resonant diffraction radiation when the grating is tilted. In the report we present simulation results and detailed experimental plan.

TUPD39

Observation of Synchrotron Radiation Using Low Noise Block (LNB) at ANKA

radiation, synchrotron, storage-ring, synchrotron-radiation

389

V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale
KIT, Karlsruhe, Germany
F. Caspers
CERN, Geneva, Switzerland

Funding: Work supported by the Initiative and Networking Fund of the Helmholtz Association under contact number VH-NG-320
Generally Coherent Synchrotron Radiation (CSR) is emitted for wavelengths longer than or equal the bunch length, so for CSR in the THz-range short bunches are required. There are two types of detectors in this range of the spectrum: slow detectors like a golay cell or pyrometric detectors (used for e.g. imaging, spectroscopy) and fast detectors like superconducting bolometer detector systems and Schottky Barrier diodes (used for e.g. the investigation of dynamic processes in accelerator physics). The hot electron bolometer (HEB) detector system is a member of second group. It is very fast and has broad spectral characteristics, but unfortunately very expensive and have to be cooled using liquid helium. If the broad spectral response is not important, it will be suitably to use a Schottky Barrier diode instead. These detectors are massively cheaper but also slower. As an alternative to a Schottky diode a LNB (Low Noise Block) can be also used. It is usually used in standard TV-SAT-receivers. Due to mass production LNBs became very cheap, moreover they are optimized to detect very low intensity "noise-like" signals. In this paper we present our experience with a LNB at ANKA.

TUPD42

Design and Experiences with the Beam Condition Monitor as Protection System in the CMS Experiment of the LHC

background, monitoring, beam-losses, radiation

398

M. Guthoff
CERN, Geneva, Switzerland

The Beam Condition Monitor (BCM) is used as protection system. In order to prevent damage to the pixel and tracker detectors it can trigger a beam dump when extremely high beam losses occur. The system consists of BCM1L with 4 diamonds per side at 1.8m away from the interaction point and BCM2 with 4 inner and 8 outer diamonds per side at 14.4m away from the interaction point. As detector material poly-crystalline CVD diamonds are used. The readout electronics is identical to the Beam Loss Monitor (BLM) system of the LHC. With cross calibration measurements a direct comparison between the BLM and the BCM systems is possible. The BCM system is therefore a transparent extension of the BLM system into the CMS cavern. The BCM2 system has been active in the beam abort system since the beginning of collisions at the LHC. Design and performance of the system during the run of the LHC so far will be presented.
*on behalf of the CMS BRM group.

Poster TUPD42 [0.736 MB]

TUPD52

First Measurements with the Test Stand for Optical Beam Tomography

ion, luminosity, beam-transport, photon

422

C. Wagner, O. Meusel, U. Ratzinger, H. Reichau
IAP, Frankfurt am Main, Germany

A test stand for optical beam tomography was developed. As a new non-destructive beam-diagnostic system for high current ion beams, the test stand will be installed in the low energy beam transport section (LEBT) of the Frankfurt Neutron Source (FRANZ) behind the chopper system. The test stand consists of a rotatable vacuum chamber with a mounted CCD camera. The maximum rotation angle amounts to 270°. In a first phase the optical beam profile measurement and 3D density reconstruction is tested with a time independent 10 keV He beam. The measurements and performance of data processing algorithms are compared with the beam transport simulations. In a later phase the performance with time dependent beams (120 keV, 200 mA) at a repetition rate of 250 kHz and a duty cycle of 2.5% has to be evaluated. An overview of the first phase results is shown.

Poster TUPD52 [13.501 MB]

TUPD55

Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN

instrumentation, impedance, dipole, electron

431

D. Egger
EPFL, Lausanne, Switzerland
A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca
CERN, Geneva, Switzerland

The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.

Poster TUPD55 [0.959 MB]

TUPD58

Non-interceptive Profile Measurements using an Optical-based Tomography Technique

diagnostics, laser, ion, simulation

437

C.M. Mateo, G. Adroit, G. Ferrand, A. France, R. Gobin, S. Nyckees, Y. Sauce, F. Senée, O. Tuske
CEA/IRFU, Gif-sur-Yvette, France

Funding: This work is supported by the DITANET Marie Curie European network
Most of the charged particle beam shapes do not possess symmetry. In such cases, diagnostic measurement obtained in one direction is not enough to reconstruct the spatial distribution of the beam. The use of intense beams which demands for non-interceptive diagnostic devices posed another challenge in measuring the beam’s spatial distribution. At CEA Saclay and within the DITANET framework, the use of tomography combined with optical diagnostics to develop a non-interceptive transverse profile monitor is under development. This profile monitor is presently tested on the BETSI test bench. In this contribution, a tomography algorithm suited for beam profile measurements is presented. This algorithm is based on the formulation of iterative Algebraic Reconstruction Technique (ART) problem and the Maximum-Likelihood Expectation Maximization (MLEM) for the iteration step. The algorithm is optimized within the limit of using 6 projections only. Several beam shapes are generated and then reconstructed computationally. Actual measurements in the BETSI test bench are also done to verify the tomographic reconstruction process.

TUPD63

Gas Electron Multipliers for the Antiproton Decelerator

electron, antiproton, cathode, high-voltage

449

S.C. Duarte Pinto, O.R. Jones, L. Ropelewski, J. Spanggaard, G. Tranquille
CERN, Geneva, Switzerland

The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light (~0.4% X₀), and measures horizontal and vertical profiles directly in one plane. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPCs) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another 3 detectors now installed in the ASACUSA beam line. This paper will provide a detailed description of the detector and discuss the initial results obtained.

TUPD64

Test Measurements of a 20 m/s Carbon Wire Beam Scanner

controls, simulation, feedback, acceleration

452

M. Koujili, J. De Freitas, B. Dehning, J. Emery, J.F. Herranz Alvarez, D. Ramos, M. Sapinski
CERN, Geneva, Switzerland
Y. Ait Amira
UFC, Besançon, France
A. Djerdir
UTBM, Belfort, France

This paper presents the design of the actuator for the fast and high accuracy Wire Scanner system. The actuator consists of a rotary brush-less synchronous motor with the permanent magnet rotor installed inside the vacuum chamber and the stator installed outside. The fork, permanent magnet rotor and two angular position sensors are mounted on the same axis and located inside the beam vacuum chamber. The system has to resist a bake-out temperature of 200°C and ionizing radiation up to tenths of kGy/year. Maximum wire travelling speed of 20 m/s and a position measurement accuracy of 4 μm is required. Therefore, the system must avoid generating vibration and electromagnetic interference. A digital feedback controller will allow maximum flexibility for the loop parameters and feeds the 3-phase linear power driver. The performance of the presented design is investigated through simulations and experimental tests.

TUPD65

Four-Dimensional Transverse Emittance Measurement Unit for High Intensity Ion Beams

emittance, ion, rfq, background

455

S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.R. Lu, Z.X. Yuan, J. Zhao
PKU/IHIP, Beijing, People's Republic of China
H.T. Ren
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China
An X-Y coplaner High Intensity Beam Emittance Measurement Unit named as HIBEMU-4 has been developed recently to measure the emmitance of 2 MeV/40mA D⁺ beam at the RFQ exit of PeKing University Neutron Imaging FaciliTY (PKUNIFTY). HIBEMU-4 is based on the slit-wire method, and has two groups of slits in the orthogonal directions. Equipped with user-oriented software, it is able to provide results as root-mean-square(rms) emittance, boundary emittance, Twiss-parameters and phase diagram. In this paper we will mainly discuss the strengths and limitations of HIBEMU-4 at the aspects of mechanical designing and data processing method. In addition the testing of HIBEMU-4 on 1MeV O+ beam as well as 2 MeV/40mA D⁺ is closely presented, which shows HIBEMU-4 is competent in high intensity beam (HIB) emmitance measurements.

TUPD69

Operational Experience and Improvements of the LHC Beam Current Transformers

feedback, luminosity, proton, diagnostics

467

P. Odier, D. Belohrad, J-J. Gras, M. Ludwig
CERN, Geneva, Switzerland

During the 2010 run the LHC continuously improved its performance. In particular the bunch charge and number of bunches were significantly increased, which revealed certain limitations of the LHC beam current transformers. The DC current transformers (DCCT), used to measure the circulating beam current, exhibited saturation related to bunch intensity, the number of batches in the machine and their spacing. Two major issues were also discovered on the fast beam current transformers (FBCT) used to measure the individual bunch charges: discrepancies in the measured intensities when compared to the DCCTs measurements and a bunch length dependence on the measured intensity. Further analysis showed that both problems are linked to the beam position dependence of the signal acquired from the toroids used in the FBCTs. This paper presents the observed issues, discusses possible solutions and reports on the results from modification made for the 2011 run.

TUPD93

Diagnostics of RF Breakdowns in High-Gradient Accelerating Structures

collider, plasma, electron, linear-collider

527

A. Palaia
Uppsala University, Uppsala, Sweden
V.A. Dolgashev, J.R. Lewandowski, S.P. Weathersby
SLAC, Menlo Park, California, USA

Within the framework of the research on high-gradient accelerating structures for future linear colliders, diagnostics of radio-frequency (RF) breakdowns is of great importance to support the understanding of the vacuum breakdown process. Measurements of RF and electron and ion currents emitted during and after a breakdown can be used to calculate the properties of any objects responsible for such power reflection and charge emission. Possible breakdown models, breakdown localization and a time-scale of the process are here discussed and compared to dedicated measurements. First results are presented.

Poster TUPD93 [7.029 MB]

WEOC01

Beam Charge Measurements

coupling, impedance, pick-up, linac

564

D. Belohrad
CERN, Geneva, Switzerland

The measurement of beam charge is fundamental to all particle accelerators. There exist many methods to achieve this, which can broadly be classified into two categories: intercepting measurements, which are destructive for the beam and result in absorption of a significant amount of energy; non-intercepting measurements using electric or magnetic field coupling. In both categories one can find instruments that process the beam signals with high dynamic range, both in amplitude and time. The aim of this article is to present the current state of beam charge measurement technology. Various measurement methods will be described with their uses, advantages, and achievable resolution and accuracy discussed. The technological problems related to their fabrication will also be addressed.

Slides WEOC01 [5.738 MB]