IBIC2013 - List of Keywords (CERN)

Paper	Title	Other Keywords	Page
MOPC17	Calibration of a Non-Linear Beam Position Monitor Electronics by Switching Electrode Signals	BPM, beam-position, LHC, SPS	85
	M. Gasior CERN, Geneva, Switzerland
	Button electrode signals from beam position monitors embedded into new LHC collimators will be individually processed with front-end electronics based on compensated diode detectors and digitized with 24-bit audio-range ADCs. This scheme allows sub-micrometre beam orbit resolution to be achieved with simple hardware and no external timing. As the diode detectors only operate in a linear regime with large amplitude signals, offset errors of the electronics cannot be calibrated in the classical way with no input. This paper describes the algorithms developed to calibrate the offset and gain asymmetry of these nonlinear electronic channels. Presented algorithm application examples are based on measurements performed with prototype diode orbit systems installed on the CERN SPS and LHC machines.

MOPC18	Development of a High Dynamic Range Beam Position Measurement System Using Logarithmic Amplifiers for the SPS at CERN	SPS, injection, beam-position, proton	89
	J.L. Gonzalez, T.B. Bogey, C. Deplano, J.-J. Savioz CERN, Geneva, Switzerland
	A new Front-End electronics, based on Logarithmic Amplifiers, is currently being developed for the CERN SPS Multi Orbit POsition System (MOPOS). The aim is to resolve the multi-batch structure of the beams and cope with their large intensity range (> 70 dB). Position and intensity signals are digitized in the Front-End electronics installed in the tunnel. The data are then transmitted over a serial fibre-optic link to a VME Digital Acquisition board located in surface buildings. A first prototype, equipped with a calibration system, has been successfully tested on the SPS under different beam conditions, including single bunch, 25ns and 50ns bunch trains. The system architecture and the first beam measurements are reported in this paper.
	Poster MOPC18 [4.013 MB]

MOPC20	Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics	synchrotron, BPM, CTF3, diagnostics	97
	R.J. Steinhagen CERN, Geneva, Switzerland M.J. Boland SLSA, Clayton, Australia T.G. Lucas, R.P. Rassool The University of Melbourne, Melbourne, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan
	The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators the use of optical diagnostic techniques for this purpose is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependable means to measure signals deriving from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN's CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The used amplification schemes, achieved sensitivities, linearity, and dynamic range of the detector setup are presented.
	Poster MOPC20 [3.065 MB]

MOPC28	The Hardware Implementation of the CERN SPS Ultrafast Feedback Processor Demonstrator	feedback, controls, SPS, FIR	124
	J.E. Dusatko, J.M. Cesaratto, J.D. Fox, J.J. Olsen, C.H. Rivetta SLAC, Menlo Park, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP) An ultrafast 4GSa/s transverse feedback processor has been developed for proof-of-concept studies of feedback control of e-cloud driven and transverse mode coupled intra-bunch instabilities in the CERN SPS. This system consists of a high-speed ADC on the front end and equally fast DAC on the back end. All control and signal processing is implemented in FPGA logic. This system is capable of taking up to 16 sample slices across a single SPS bunch and processing each slice individually within a reconfigurable signal processor. This demonstrator system is a rapidly developed prototype, consisting of both commercial and custom-design components. It can stabilize the motion of a single particle bunch using closed loop feedback. The system can also run open loop as a high-speed arbitrary waveform generator and contains diagnostic features including a special ADC snapshot capture memory. This paper describes the overall system, the feedback processor and focuses on the hardware architecture, design and implementation.
	Poster MOPC28 [1.684 MB]

MOPC35	A Beam-Synchronous Gated Peak-Detector for the LHC Beam Observation System	LHC, longitudinal, injection, synchrotron	147
	T.E. Levens, T. Bohl, U. Wehrle CERN, Geneva, Switzerland
	Measurements of the bunch peak amplitude using the longitudinal wideband wall-current monitor are a vital tool used in the Large Hadron Collider (LHC) beam observation system. These peak-detected measurements can be used to diagnose bunch shape oscillations, for example coherent quadrupole oscillations, that occur at injection and during beam manipulations. Peak-detected Schottky diagnostics can also be used to obtain the synchrotron frequency distribution and other parameters from a bunched beam under stable conditions. For the LHC a beam-synchronous gated peak detector has been developed to allow individual bunches to be monitored without the influence of other bunches circulating in the machine. The requirement for the observation of both low intensity pilot bunches and high intensity bunches for physics requires a detector front-end with a high bandwidth and a large dynamic range while the usage for Schottky measurements requires low noise electronics. This paper will present the design of this detector system as well as initial results obtained during the 2012-2013 LHC run.
	Poster MOPC35 [2.792 MB]

MOPC44	A Gigabit Ethernet Link for an FPGA Based Beam Loss Measurement System	beam-losses, monitoring, instrumentation, LHC	178
	M. Kwiatkowski, M. Alsdorf, B. Dehning, W. Viganò, C. Zamantzas CERN, Geneva, Switzerland
	A new Beam Loss Measurement (BLM) system is under development at the European Organisation for Nuclear Research (CERN) within the LHC Injector Upgrade (LIU) project. The multi-channel system will measure the beam losses from various types of detectors with a high precision and wide dynamic range. Several modes of data acquisition are supported. The data rate in the single-channel mode is 16 Mbps and in the multi-channel mode 128 Mbps. The Gigabit Ethernet link is implemented in an FPGA, which allows both a high throughput and a quick validation of the digital data processing algorithms using standard PCs in the initial stages of the development. Both TCP and UDP protocols were explored. The implementation of the Ethernet link is flexible and proved to be highly reliable, leading to its planned use in other measurement systems developed at CERN. The implementation details of the Ethernet link and the results achieved will be described in this paper.
	Poster MOPC44 [0.833 MB]

MOPF24	Magnetic Materials for Current Transformers	vacuum, impedance, damping, GSI	263
	S. Aguilera, P. Odier, R. Ruffieux CERN, Geneva, Switzerland
	At CERN, the circulating beam current measurement is provided by two types of transformers, the Direct Current Current Transformers (DCCT) and the Fast Beam Current Transformers (FBCT). Each type of transformer requires different magnetic characteristics regarding parameters such as permeability, coercivity and shape of the magnetization curve. Each transformer is built based on toroidal cores of a magnetic material which gives these characteristics. For example, DCCTs consist of three cores, two for the measurement of the DC component and one for the AC component. In order to study the effect of changes in these parameters on the current transformers, several interesting raw materials based on their as-cast properties were selected with the annealing process used to tune their properties for the individual needs of each transformer. First annealing tests show that the magnetization curve, and therefore the permeability, of the material can be modified, opening the possibility for building and studying a variety of transformer cores.
	Poster MOPF24 [1.185 MB]

MOPF25	Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators	antiproton, shielding, longitudinal, cryogenics	267
	M.F. Fernandes, J. Tan CERN, Geneva, Switzerland M.F. Fernandes, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom M.F. Fernandes, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by the EU within the oPAC project under contract 289485. In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results from a comparative analysis of different monitor options, taking into consideration the external electromagnetic sources at the foreseen device locations.
	Poster MOPF25 [1.059 MB]

MOPF29	A Non-Invasive Beam Monitor for Hadron Therapy Beams	proton, target, LHC, vacuum	283
	T. Cybulski, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom T. Cybulski, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Kacperek, B. Marsland, I. Taylor, A. Wray The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
	Funding: Work supported by the EU under contract PITN-GA-2008-215080 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1 Hadron therapy allows for precise dose delivery to the tumour volume only and hence decreases the dose delivered to the nearby organs and healthy tissue. Ideally, the beam would be monitored whilst being delivered to the patient. A novel, real–time and non-interceptive beam monitor for hadron therapy beams has been developed in the QUASAR Group. It is based on the LHCb VErtex LOcator (VELO) detector and couples to the treatment beam’s transverse halo to determine the intensity, position and ultimately the dose of the treatment beam. This contribution presents the design of a stand-alone version of the VELO detector which was developed for the Clatterbridge Cancer Centre (CCC) treatment line. The mechanical and electronic design of the monitor and its data acquisition system are shown, with a focus on the detector positioning and cooling system. Monte Carlo simulations into expected signal distributions are compared against first measurements with the 60 MeV proton beam at CCC.

TUBL3	A Multiband-Instability-Monitor for High-Frequency Intra-Bunch Beam Diagnostics	LHC, SPS, synchrotron, pick-up	327
	R.J. Steinhagen CERN, Geneva, Switzerland M.J. Boland, T.G. Lucas The University of Melbourne, Melbourne, Australia
	To provide the best possible luminosity, even higher beam intensities are needed in the Large Hadron Collider (LHC) and in its injector chain. This is fundamentally limited by self-amplifying beam instabilities, intrinsic to unavoidable imperfections in accelerators. Traditionally, intra-bunch or head-tail particle motion is measured using fast digitizers, which even using state-of-the-art technology are limited in their effective intra-bunch position resolution to few tens of um in the multi-GHz regime. Oscillations at this scale cause partial or total loss of the beam due to the tight transverse constraints imposed by the LHC collimation system. To improve on the present signal processing, a prototype system has been designed, constructed and tested at the CERN Super-Proton-Synchrotron (SPS) and later on LHC. The system splits the signal into multiple equally-spaced narrow frequency bands that are processed and analysed in parallel. Working with narrow-band signals in frequency-domain permits the use of much higher resolution analogue-to-digital-converters that can be used to resolve nm-scale particle motion already during the onset of instabilities.
	Slides TUBL3 [3.165 MB]

TUCL3	Gas Electron Multipliers Versus Multi Wire Proportional Chambers	electron, antiproton, ion, transverse	342
	S.C. Duarte Pinto Delft University of Technology, Opto-electronic Section, Delft, The Netherlands J. Spanggaard CERN, Geneva, Switzerland
	Gas Electron Multiplication technology is finding more and more applications in beam instrumentation and at CERN these detectors have recently been adapted for use in transverse profile measurements at several of our facilities. In the experimental areas of CERN’s Antiproton Decelerator, low energy Gas Electron Multipliers successfully replaced all Multi-Wire Proportional Chambers in 2012 and another detector type has now been developed for high energy applications in the experimental areas of the SPS, totalling a potential of more than a hundred profile detectors to be replaced by GEM detectors of different types. This paper aims to describe the historical evolution of GEM technology by covering the many different applications but with specific focus on its potential to replace Multi-Wire Proportional Chambers for standard transverse profile measurement.
	Slides TUCL3 [3.275 MB]

TUPF02	Secondary Emission Monitor for keV Ion and Antiproton Beams	MCP, antiproton, electron, ion	495
	A.G. Sosa, E. Bravin, A. Jeff CERN, Geneva, Switzerland J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1. Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 10⁷ and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities. Measurements at the AD carried out with the AEgIS collaboration.
	Poster TUPF02 [1.934 MB]

TUPF03	Performance Assessment of Wire-Scanners at CERN	LHC, SPS, laser, synchrotron	499
	G. Baud, B. Dehning, J. Emery, J-J. Gras, A. Guerrero, E.P. Piselli CERN, Geneva, Switzerland
	This article describes the current fast wire-scanner devices installed in circular accelerators at CERN with an emphasis of the error studies carried out during the last two runs. At present the wire-scanners have similar acquisition systems but are varied in terms of mechanics. Several measurement campaigns were performed aimed at establishing optimal operational settings and to identify and assess systematic errors. In several cases the results led to direct performance improvements while in others this helped in defining the requirements for new detectors.
	Poster TUPF03 [1.040 MB]

TUPF15	Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators	laser, linac, emittance, ion	531
	S.M. Gibson, G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.
	Poster TUPF15 [9.196 MB]

TUPF27	An Ultra Low-Noise AC Beam Transformer and Digital Signal Processing System for CERN’s ELENA Ring	diagnostics, pick-up, longitudinal, extraction	571
	M.E. Angoletta, C. Carli, F. Caspers, S. Federmann, J.C. Molendijk, F. Pedersen, J. Sanchez-Quesada CERN, Geneva, Switzerland
	CERN’s Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator. Essential longitudinal diagnostics required for commissioning and operation include the intensity measurement for bunched and debunched beams and the measurement of Dp/p for debunched beams to assess the electron cooling performance. The beam phase information is also needed by the low-level RF system. The baseline system for providing the required beam parameters and signals is based upon two ultra-low-noise AC beam transformers and associated digital signal processing. The AC beam transformers cover different frequency regions and are an adaptation to the ELENA layout of those used in the AD. Two AC beam transformers will also be installed in the extraction lines to provide beam intensity and bunch shape measurements. The digital signal processing will be carried out with the leading-edge hardware family used for ELENA’s low-level RF system. The paper provides an overview of the beam transformer and head amplifier, as well as of the associated digital signal processing.

TUPF28	A Leading-Edge Hardware Family for Diagnostics Applications and Low-Level RF in CERN’s ELENA Ring	controls, antiproton, synchrotron, diagnostics	575
	M.E. Angoletta, A. Blas, M. Jaussi, P.M. Leinonen, T.E. Levens, J.C. Molendijk, J. Sanchez-Quesada, J. Simonin CERN, Geneva, Switzerland
	The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons transferred from the CERN’s Antiproton Decelerator (AD). The requirements for the acquisition and treatment of signals for longitudinal diagnostics are very demanding, owing to the revolution frequency swing as well as to the digital signal processing required. The requirements for the Low-Level RF (LLRF) system are very demanding as well, especially in terms of revolution frequency swing, dynamic range and low noise required by the cavity voltage control and digital signal processing to be performed. Both sets of requirements will be satisfied by using a leading-edge hardware family, developed to cover the LLRF needs of all synchrotrons in the Meyrin site; it will be first deployed in 2014 in the CERN’s PSB and in the medical machine MedAustron. This paper gives an overview of the main building blocks of the hardware family and of the associated firmware and IP cores. The performance of some blocks will also be detailed.

TUPF29	Tune Measurement from Transverse Feedback Signals in LHC	feedback, transverse, LHC, damping	579
	F. Dubouchet, W. Höfle, G. Kotzian, T.E. Levens, D. Valuch CERN, Geneva, Switzerland P. Albuquerque HES-SO//Geneva, Geneva, Switzerland
	We show how bunch-by-bunch position data from the LHC transverse feedback system can be used to determine the transverse tunes. Results from machine development experiments are presented and compared with theoretical predictions. In the absence of external beam excitations the tune is visible in the spectra of the position data with the feedback loop as a dip, while with external excitation a peak is visible. Both options, observation with and without excitation, are demonstrated to be complementary. Periodic excitation and observation of the free oscillation can also be used to determine the damping time of the feedback in addition to the coherent tune. Plans are outlined for hardware upgrades of the LHC transverse feedback system that will enable fast online processing of bunch-by-bunch, turn-by-turn data using Graphical Processing Units (GPU). By using GPUs we gain the ability to compute and store the spectrum of all bunches in real-time and the possibility to reconfigure test and deploy algorithms. This data acquisition and analysis architecture also allows changes to be made without disturbing the operation.
	Poster TUPF29 [1.052 MB]

WEAL3	Diffraction Radiation Test at CesrTA for Non-Intercepting Micron-Scale Beam Size Measurement	target, radiation, electron, CLIC	619
	L.M. Bobb, E. Bravin, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland T. Aumeyr, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom M.G. Billing, J.V. Conway Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L.M. Bobb JAI, Egham, Surrey, United Kingdom
	Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. DR can therefore be used to develop non-invasive diagnostic tools. To achieve the micron-scale resolution required to measure the transverse (vertical) beam size using incoherent DR in CLIC, DR in UV and X-ray spectral-range must be investigated. Experimental validation of such a scheme is ongoing at CesrTA at Cornell University, USA. Here we report on the test using 0.5 mm and 1 mm target apertures on a 2.1 GeV electron beam and 400 nm wavelength.
	Slides WEAL3 [2.893 MB]

WEBL3	Wake Field Monitors in a Multi Purpose X Band Accelerating Structure	alignment, dipole, longitudinal, emittance	634
	M.M. Dehler, S. Bettoni, B. Beutner, G. De Michele PSI, Villigen PSI, Switzerland G. De Michele EPFL, Lausanne, Switzerland G. De Michele CERN, Geneva, Switzerland
	In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. These feature integrated wake field monitors (WFMs), which are used to measure the alignment (offset and tilt) between structure and beam. One structure has recently been installed in the SwissFEL Injector Test facility (SITF) at PSI. The WFM front end electronics will be developed within the EuCard2 framework, so for the measurements described in this paper we used the raw WFM signals. We compare these measurements to the theoretical results obtained via an equivalent circuit model used in the design and numerical calculations. The beam tests show that by minimizing the WFM signals, the emittance dilution given by the transverse wakes, crucial because of the small aperture of the structure, is minimized as well.
	Slides WEBL3 [1.668 MB]

WEPC05	The ELENA Beam Diagnostics Systems	antiproton, electron, pick-up, proton	664
	G. Tranquille CERN, Geneva, Switzerland
	The Extra Low ENergy Antiproton ring (ELENA) to be built at CERN is aimed at substantially increasing the number of antiprotons to the low energy antiproton physics community. It will be a small machine which will decelerate low intensity beams (<4x10⁷) from 5.3 MeV to 100 keV and will be equipped with an electron cooler to avoid beam losses during the deceleration and to significantly reduce beam phase space at extraction. To measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and all the way to the experiments, many systems will be needed to ensure that the desired beam characteristics are obtained. Particular attention needs to be paid to the performance of the electron cooler which depends on reliable instrumentation in order to efficiently cool the antiprotons. This contribution will present the different monitors that have been proposed to measure the various beam parameters as well as some of the developments going on to further improve the ELENA diagnostics.
	Poster WEPC05 [1.767 MB]

WEPC11	Radiation Resistance Testing of Commercial Components for the New SPS Beam Position Measurement System	radiation, SPS, beam-position, BPM	686
	C. Deplano, J. Albertone, T.B. Bogey, J.L. Gonzalez, J.-J. Savioz CERN, Geneva, Switzerland
	A new Front-End (FE) electronics is under development for the SPS Multi Orbit POsition System (MOPOS). To cover the large dynamic range of beam intensities (70dB) to be measured in the SPS, the beam position monitor signals are processed using logarithmic amplifiers. They are then digitized locally and transmitted via optical fibers over long distances (up to 1km) to VME acquisition boards located in surface buildings. The FE board is designed to be located in the SPS tunnel, where it must cope with a radiation dose rate of up to 100 Gy per year. Analogue components, such as Logarithmic Amplifiers, ADC-Drivers and Voltage regulators, have been tested at PSI for radiation hardness, while several families of bidirectional SFP, both single-fiber and double-fiber, have been tested at both PSI and CNRAD. This paper gives a description of the overall system architecture and presents the results of the radiation hardness tests in detail.
	Poster WEPC11 [3.299 MB]

WEPC44	Operation of Silicon, Diamond and Liquid Helium Detectors in the Range of Room Temperature to 1.9 Kelvin and After an Irradiation Dose of Several Mega Gray	DIAMOND, proton, LHC, beam-losses	791
	C. Kurfuerst, M.R. Bartosik, B. Dehning, T. Eisel, M. Sapinski CERN, Geneva, Switzerland V. Eremin IOFFE, St. Petersburg, Russia
	At the triplet magnets close to the interaction regions of the LHC, the current Beam Loss Monitoring system is sensitive to the debris from the collision points. For future beams with higher energy and intensity, the expected increase in luminosity and associated increase of the debris from interaction products is expected to compete with any quench-provoking beam losses from the primary proton beams. In order to distinguish between the two, it is proposed to locate the detectors as close as possible to the superconducting coil. The detectors therefore have to be located inside the cold mass of the superconducting magnets in superfluid helium at 1.9 K. Past measurements have shown that in a liquid helium chamber, diamond and silicon detectors are promising candidates for cryogenic beam loss monitors. This contribution will show the results from new high irradiation beam measurements at both room temperature and 1.9 Kelvin to reveal the radiation tolerance of these different detectors.

WEPF07	Profile Grid Monitor and First Measurement Results at the MedAustron Accelerator	controls, feedback, ion, beam-transport	822
	M. Repovz, A. Gyorgy, A. Kerschbaum, F. Osmic, S.M. Schwarz EBG MedAustron, Wr. Neustadt, Austria G. Burtin CERN, Geneva, Switzerland
	MedAustron is an ion beam therapy center located in Wiener Neustadt, Austria. The design is based on CERN’s Proton-Ion Medical Machine Study and the project is currently in the installation and commissioning phase. This paper summarizes the design, production and commissioning of MedAustron’s beam profile grid monitor. This monitor measures the beam profile in the low and medium energy beam transfer line where the beam dimensions can be as large as 100 mm. Reasonable position resolution is achieved with a harp consisting of 64 wires per plane and a pitch of up to 1.7 mm. Special effort was needed to produce such harps and bring the signal cables out of the vacuum. As the readout electronics has to cope with DC as well as pulsed beam all 128 wires are acquired simultaneously. This is achieved by integrating the charge during the “flat-top” of the beam pulse and storing it for serial transmission to the back end electronics for conversion. The high accuracy requires calibration of offset and amplification errors for every single channel. A NI PXI FPGA card controls the readout chain. The code for controlling the readout, including the graphical interface, is written in NI LabView.

WEPF09	Profile and Emittance Measurements at the CERN LINAC-4 3 MeV Test Stand	emittance, linac, transverse, rfq	826
	F. Zocca, E. Bravin, M. Duraffourg, G.J. Focker, D. Gerard, U. Raich, F. Roncarolo CERN, Geneva, Switzerland
	A new 160 MeV H⁻ Linac named Linac-4 will be built at CERN to replace the old 50 MeV proton Linac. The ion source, the 3 MeV RFQ and the medium energy transport (MEBT) hosting a chopper, have been commissioned in a dedicated test stand. Wire grids and wire scanners were used to measure the transverse beam profile and a slit/grid emittance meter was installed on a temporary test bench plugged at the RFQ and MEBT exit in different stages. The emittance meter slit was also used as a scanning scraper able to reconstruct the transverse profile by measuring the transmission with a downstream current transformer. On the same measurement bench, a spectrometer in conjunction with a wire grid allowed measuring the energy spread of the particles. This paper summarizes the measurement results that allowed characterizing the 3 MeV beam and discusses the present understanding of monitor performance.

WEPF10	Wire Scanner Design for the European Spallation Source	linac, ESS, proton, diagnostics	830
	B. Cheymol, A. Jansson, T.J. Shea ESS, Lund, Sweden
	The European Spallation Source (ESS), to be built in the south of Sweden, will use a 2 GeV superconducting LINAC to produce the world's most powerful neutron source with a beam power of 5 MW. The beam power is a challenge for interceptive beam diagnostics like wire scanner, the thermal load on intercepting devices implies to reduce the beam power in order to preserve the device integrity. For nominal operation, non-disturbing techniques for profile measurements are planned, while for the commissioning phase, accurate measurements and cross checking, wire scanners will be used. This paper describes the preliminary design of the wire scanner system in the normal conducing LINAC as well as in the superconducting LINAC.

WEPF28	Longitudinal Beam Diagnostic from a Distributed Electrostatic Pick-Up in CERN’s ELENA Ring	longitudinal, pick-up, antiproton, diagnostics	883
	M.E. Angoletta, F. Caspers, S. Federmann, J.C. Molendijk, P.J. Pascal Jean, F. Pedersen, J. Sanchez-Quesada, L. Søby, M.A. Timmins CERN, Geneva, Switzerland
	The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Required longitudinal diagnostics include the intensity measurement for bunched and debunched beam and the measurement of Dp/p for a debunched beam to assess the electron cooling performance. A novel method for the calculation of these parameters is proposed for ELENA, where signals from the twenty electrostatic pick-ups (PU) used for orbit measurements will be combined to improve the signal-to-noise ratio. This requires that the signals be digitally down-converted, rotated and digitally summed so that the many electrostatic PUs will function as a single, distributed PU from to the processing system viewpoint. This method includes some challenges and will not be used as the baseline longitudinal diagnostics for the initial ELENA operation. This paper gives an overview of the hardware and digital signal processing involved, as well as of the challenges that will have to be faced.

WEPF29	The LHC Fast Beam Current Change Monitor	LHC, injection, FIR, beam-losses	887
	D. Belohrad, J.M. Belleman, L.K. Jensen, M. Krupa, A. Topaloudis CERN, Geneva, Switzerland
	The modularity of the Large Hadron Collider’s (LHC) machine protection system (MPS) allows for the integration of several beam diagnostic instruments. These instruments have not necessarily been designed to have protection functionality, but MPS can still use them to increase the redundancy and reliability of the machine. The LHC fast beam current change monitor (FBCCM) is an example. It is based on analogue signals from fast beam current transformers (FBCT) used nominally to measure the LHC bunch intensities. The FBCCM calculates the magnitude of the beam signal provided by the FBCT, looks for a change over specific time intervals, and triggers a beam dump interlock if losses exceed an energy-dependent threshold. The first prototype of the FBCCM was installed in the LHC during the 2012-2013 run. The aim of this article is to present the FBCCM system and the results obtained, analyse its current performance and provide an outlook for the final system which is expected to be operational after the long LHC shutdown.

WEPF31	A FESA DAQ for Fast Current Transformer in SIS 18	synchrotron, longitudinal, SIS, pick-up	894
	O. Chorniy, H. Bräuning, T. Hoffmann, H. Reeg, A. Reiter GSI, Darmstadt, Germany
	This contribution presents the development of the data acquisition (DAQ) system for the readout of fast beam current transformers (FCT) as installed in the GSI synchrotron SIS18 and as foreseen in several FAIR ring accelerators. Fast current transformers are reliable devices that offer a large analogue bandwidth and can therefore monitor bunch structures with high resolution. At appropriate sampling rates continuous measurements throughout repeated machine cycles lead to a large amount of raw data. The analysis of those raw data may range from simple bunch parameter calculations to complex longitudinal phase space reconstructions. Consequently, a new DAQ system must be carefully designed to allow for flexible acquisition modes or to allow for data reduction methods in special applications. The aims of the development are discussed and the status of the new DAQ is presented.
	Poster WEPF31 [2.307 MB]

THBL2	The White Rabbit Project	controls, CDR, diagnostics, radio-frequency	936
	J. Serrano, M. Cattin, G. Daniluk, E. Gousiou, M.M. Lipiński, E. Van der Bij, T. Włostowski CERN, Geneva, Switzerland
	White Rabbit (WR) is a multi-laboratory, multi-company collaboration for the development of a new Ethernet-based technology which ensures sub-nanosecond synchronisation and deterministic data transfer. The project uses an open source paradigm for the development of its hardware, gateware and software components. This article provides an introduction to the technical choices and an explanation of the basic principles underlying WR. It then describes some possible applications and the current status of the project. Finally, it provides insight on current developments and future plans.
	Slides THBL2 [5.516 MB]

Paper

Title

Other Keywords

Page

MOPC17

Calibration of a Non-Linear Beam Position Monitor Electronics by Switching Electrode Signals

BPM, beam-position, LHC, SPS

85

M. Gasior
CERN, Geneva, Switzerland

Button electrode signals from beam position monitors embedded into new LHC collimators will be individually processed with front-end electronics based on compensated diode detectors and digitized with 24-bit audio-range ADCs. This scheme allows sub-micrometre beam orbit resolution to be achieved with simple hardware and no external timing. As the diode detectors only operate in a linear regime with large amplitude signals, offset errors of the electronics cannot be calibrated in the classical way with no input. This paper describes the algorithms developed to calibrate the offset and gain asymmetry of these nonlinear electronic channels. Presented algorithm application examples are based on measurements performed with prototype diode orbit systems installed on the CERN SPS and LHC machines.

MOPC18

Development of a High Dynamic Range Beam Position Measurement System Using Logarithmic Amplifiers for the SPS at CERN

SPS, injection, beam-position, proton

89

J.L. Gonzalez, T.B. Bogey, C. Deplano, J.-J. Savioz
CERN, Geneva, Switzerland

A new Front-End electronics, based on Logarithmic Amplifiers, is currently being developed for the CERN SPS Multi Orbit POsition System (MOPOS). The aim is to resolve the multi-batch structure of the beams and cope with their large intensity range (> 70 dB). Position and intensity signals are digitized in the Front-End electronics installed in the tunnel. The data are then transmitted over a serial fibre-optic link to a VME Digital Acquisition board located in surface buildings. A first prototype, equipped with a calibration system, has been successfully tested on the SPS under different beam conditions, including single bunch, 25ns and 50ns bunch trains. The system architecture and the first beam measurements are reported in this paper.

Poster MOPC18 [4.013 MB]

MOPC20

Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics

synchrotron, BPM, CTF3, diagnostics

97

R.J. Steinhagen
CERN, Geneva, Switzerland
M.J. Boland
SLSA, Clayton, Australia
T.G. Lucas, R.P. Rassool
The University of Melbourne, Melbourne, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan

The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators the use of optical diagnostic techniques for this purpose is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependable means to measure signals deriving from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN's CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The used amplification schemes, achieved sensitivities, linearity, and dynamic range of the detector setup are presented.

Poster MOPC20 [3.065 MB]

MOPC28

The Hardware Implementation of the CERN SPS Ultrafast Feedback Processor Demonstrator

feedback, controls, SPS, FIR

124

J.E. Dusatko, J.M. Cesaratto, J.D. Fox, J.J. Olsen, C.H. Rivetta
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
An ultrafast 4GSa/s transverse feedback processor has been developed for proof-of-concept studies of feedback control of e-cloud driven and transverse mode coupled intra-bunch instabilities in the CERN SPS. This system consists of a high-speed ADC on the front end and equally fast DAC on the back end. All control and signal processing is implemented in FPGA logic. This system is capable of taking up to 16 sample slices across a single SPS bunch and processing each slice individually within a reconfigurable signal processor. This demonstrator system is a rapidly developed prototype, consisting of both commercial and custom-design components. It can stabilize the motion of a single particle bunch using closed loop feedback. The system can also run open loop as a high-speed arbitrary waveform generator and contains diagnostic features including a special ADC snapshot capture memory. This paper describes the overall system, the feedback processor and focuses on the hardware architecture, design and implementation.

Poster MOPC28 [1.684 MB]

MOPC35

A Beam-Synchronous Gated Peak-Detector for the LHC Beam Observation System

LHC, longitudinal, injection, synchrotron

147

T.E. Levens, T. Bohl, U. Wehrle
CERN, Geneva, Switzerland

Measurements of the bunch peak amplitude using the longitudinal wideband wall-current monitor are a vital tool used in the Large Hadron Collider (LHC) beam observation system. These peak-detected measurements can be used to diagnose bunch shape oscillations, for example coherent quadrupole oscillations, that occur at injection and during beam manipulations. Peak-detected Schottky diagnostics can also be used to obtain the synchrotron frequency distribution and other parameters from a bunched beam under stable conditions. For the LHC a beam-synchronous gated peak detector has been developed to allow individual bunches to be monitored without the influence of other bunches circulating in the machine. The requirement for the observation of both low intensity pilot bunches and high intensity bunches for physics requires a detector front-end with a high bandwidth and a large dynamic range while the usage for Schottky measurements requires low noise electronics. This paper will present the design of this detector system as well as initial results obtained during the 2012-2013 LHC run.

Poster MOPC35 [2.792 MB]

MOPC44

A Gigabit Ethernet Link for an FPGA Based Beam Loss Measurement System

beam-losses, monitoring, instrumentation, LHC

178

M. Kwiatkowski, M. Alsdorf, B. Dehning, W. Viganò, C. Zamantzas
CERN, Geneva, Switzerland

A new Beam Loss Measurement (BLM) system is under development at the European Organisation for Nuclear Research (CERN) within the LHC Injector Upgrade (LIU) project. The multi-channel system will measure the beam losses from various types of detectors with a high precision and wide dynamic range. Several modes of data acquisition are supported. The data rate in the single-channel mode is 16 Mbps and in the multi-channel mode 128 Mbps. The Gigabit Ethernet link is implemented in an FPGA, which allows both a high throughput and a quick validation of the digital data processing algorithms using standard PCs in the initial stages of the development. Both TCP and UDP protocols were explored. The implementation of the Ethernet link is flexible and proved to be highly reliable, leading to its planned use in other measurement systems developed at CERN. The implementation details of the Ethernet link and the results achieved will be described in this paper.

Poster MOPC44 [0.833 MB]

MOPF24

Magnetic Materials for Current Transformers

vacuum, impedance, damping, GSI

263

S. Aguilera, P. Odier, R. Ruffieux
CERN, Geneva, Switzerland

At CERN, the circulating beam current measurement is provided by two types of transformers, the Direct Current Current Transformers (DCCT) and the Fast Beam Current Transformers (FBCT). Each type of transformer requires different magnetic characteristics regarding parameters such as permeability, coercivity and shape of the magnetization curve. Each transformer is built based on toroidal cores of a magnetic material which gives these characteristics. For example, DCCTs consist of three cores, two for the measurement of the DC component and one for the AC component. In order to study the effect of changes in these parameters on the current transformers, several interesting raw materials based on their as-cast properties were selected with the annealing process used to tune their properties for the individual needs of each transformer. First annealing tests show that the magnetization curve, and therefore the permeability, of the material can be modified, opening the possibility for building and studying a variety of transformer cores.

Poster MOPF24 [1.185 MB]

MOPF25

Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators

antiproton, shielding, longitudinal, cryogenics

267

M.F. Fernandes, J. Tan
CERN, Geneva, Switzerland
M.F. Fernandes, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M.F. Fernandes, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by the EU within the oPAC project under contract 289485.
In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results from a comparative analysis of different monitor options, taking into consideration the external electromagnetic sources at the foreseen device locations.

Poster MOPF25 [1.059 MB]

MOPF29

A Non-Invasive Beam Monitor for Hadron Therapy Beams

proton, target, LHC, vacuum

283

T. Cybulski, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T. Cybulski, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Kacperek, B. Marsland, I. Taylor, A. Wray
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom

Funding: Work supported by the EU under contract PITN-GA-2008-215080 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1
Hadron therapy allows for precise dose delivery to the tumour volume only and hence decreases the dose delivered to the nearby organs and healthy tissue. Ideally, the beam would be monitored whilst being delivered to the patient. A novel, real–time and non-interceptive beam monitor for hadron therapy beams has been developed in the QUASAR Group. It is based on the LHCb VErtex LOcator (VELO) detector and couples to the treatment beam’s transverse halo to determine the intensity, position and ultimately the dose of the treatment beam. This contribution presents the design of a stand-alone version of the VELO detector which was developed for the Clatterbridge Cancer Centre (CCC) treatment line. The mechanical and electronic design of the monitor and its data acquisition system are shown, with a focus on the detector positioning and cooling system. Monte Carlo simulations into expected signal distributions are compared against first measurements with the 60 MeV proton beam at CCC.

TUBL3

A Multiband-Instability-Monitor for High-Frequency Intra-Bunch Beam Diagnostics

LHC, SPS, synchrotron, pick-up

327

R.J. Steinhagen
CERN, Geneva, Switzerland
M.J. Boland, T.G. Lucas
The University of Melbourne, Melbourne, Australia

To provide the best possible luminosity, even higher beam intensities are needed in the Large Hadron Collider (LHC) and in its injector chain. This is fundamentally limited by self-amplifying beam instabilities, intrinsic to unavoidable imperfections in accelerators. Traditionally, intra-bunch or head-tail particle motion is measured using fast digitizers, which even using state-of-the-art technology are limited in their effective intra-bunch position resolution to few tens of um in the multi-GHz regime. Oscillations at this scale cause partial or total loss of the beam due to the tight transverse constraints imposed by the LHC collimation system. To improve on the present signal processing, a prototype system has been designed, constructed and tested at the CERN Super-Proton-Synchrotron (SPS) and later on LHC. The system splits the signal into multiple equally-spaced narrow frequency bands that are processed and analysed in parallel. Working with narrow-band signals in frequency-domain permits the use of much higher resolution analogue-to-digital-converters that can be used to resolve nm-scale particle motion already during the onset of instabilities.

Slides TUBL3 [3.165 MB]

TUCL3

Gas Electron Multipliers Versus Multi Wire Proportional Chambers

electron, antiproton, ion, transverse

342

S.C. Duarte Pinto
Delft University of Technology, Opto-electronic Section, Delft, The Netherlands
J. Spanggaard
CERN, Geneva, Switzerland

Gas Electron Multiplication technology is finding more and more applications in beam instrumentation and at CERN these detectors have recently been adapted for use in transverse profile measurements at several of our facilities. In the experimental areas of CERN’s Antiproton Decelerator, low energy Gas Electron Multipliers successfully replaced all Multi-Wire Proportional Chambers in 2012 and another detector type has now been developed for high energy applications in the experimental areas of the SPS, totalling a potential of more than a hundred profile detectors to be replaced by GEM detectors of different types. This paper aims to describe the historical evolution of GEM technology by covering the many different applications but with specific focus on its potential to replace Multi-Wire Proportional Chambers for standard transverse profile measurement.

Slides TUCL3 [3.275 MB]

TUPF02

Secondary Emission Monitor for keV Ion and Antiproton Beams

MCP, antiproton, electron, ion

495

A.G. Sosa, E. Bravin, A. Jeff
CERN, Geneva, Switzerland
J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 10⁷ and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN*. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.
* Measurements at the AD carried out with the AEgIS collaboration.

Poster TUPF02 [1.934 MB]

TUPF03

Performance Assessment of Wire-Scanners at CERN

LHC, SPS, laser, synchrotron

499

G. Baud, B. Dehning, J. Emery, J-J. Gras, A. Guerrero, E.P. Piselli
CERN, Geneva, Switzerland

This article describes the current fast wire-scanner devices installed in circular accelerators at CERN with an emphasis of the error studies carried out during the last two runs. At present the wire-scanners have similar acquisition systems but are varied in terms of mechanics. Several measurement campaigns were performed aimed at establishing optimal operational settings and to identify and assess systematic errors. In several cases the results led to direct performance improvements while in others this helped in defining the requirements for new detectors.

Poster TUPF03 [1.040 MB]

TUPF15

Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators

laser, linac, emittance, ion

531

S.M. Gibson, G.E. Boorman, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.

Poster TUPF15 [9.196 MB]

TUPF27

An Ultra Low-Noise AC Beam Transformer and Digital Signal Processing System for CERN’s ELENA Ring

diagnostics, pick-up, longitudinal, extraction

571

M.E. Angoletta, C. Carli, F. Caspers, S. Federmann, J.C. Molendijk, F. Pedersen, J. Sanchez-Quesada
CERN, Geneva, Switzerland

CERN’s Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator. Essential longitudinal diagnostics required for commissioning and operation include the intensity measurement for bunched and debunched beams and the measurement of Dp/p for debunched beams to assess the electron cooling performance. The beam phase information is also needed by the low-level RF system. The baseline system for providing the required beam parameters and signals is based upon two ultra-low-noise AC beam transformers and associated digital signal processing. The AC beam transformers cover different frequency regions and are an adaptation to the ELENA layout of those used in the AD. Two AC beam transformers will also be installed in the extraction lines to provide beam intensity and bunch shape measurements. The digital signal processing will be carried out with the leading-edge hardware family used for ELENA’s low-level RF system. The paper provides an overview of the beam transformer and head amplifier, as well as of the associated digital signal processing.

TUPF28

A Leading-Edge Hardware Family for Diagnostics Applications and Low-Level RF in CERN’s ELENA Ring

controls, antiproton, synchrotron, diagnostics

575

M.E. Angoletta, A. Blas, M. Jaussi, P.M. Leinonen, T.E. Levens, J.C. Molendijk, J. Sanchez-Quesada, J. Simonin
CERN, Geneva, Switzerland

The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons transferred from the CERN’s Antiproton Decelerator (AD). The requirements for the acquisition and treatment of signals for longitudinal diagnostics are very demanding, owing to the revolution frequency swing as well as to the digital signal processing required. The requirements for the Low-Level RF (LLRF) system are very demanding as well, especially in terms of revolution frequency swing, dynamic range and low noise required by the cavity voltage control and digital signal processing to be performed. Both sets of requirements will be satisfied by using a leading-edge hardware family, developed to cover the LLRF needs of all synchrotrons in the Meyrin site; it will be first deployed in 2014 in the CERN’s PSB and in the medical machine MedAustron. This paper gives an overview of the main building blocks of the hardware family and of the associated firmware and IP cores. The performance of some blocks will also be detailed.

TUPF29

Tune Measurement from Transverse Feedback Signals in LHC

feedback, transverse, LHC, damping

579

F. Dubouchet, W. Höfle, G. Kotzian, T.E. Levens, D. Valuch
CERN, Geneva, Switzerland
P. Albuquerque
HES-SO//Geneva, Geneva, Switzerland

We show how bunch-by-bunch position data from the LHC transverse feedback system can be used to determine the transverse tunes. Results from machine development experiments are presented and compared with theoretical predictions. In the absence of external beam excitations the tune is visible in the spectra of the position data with the feedback loop as a dip, while with external excitation a peak is visible. Both options, observation with and without excitation, are demonstrated to be complementary. Periodic excitation and observation of the free oscillation can also be used to determine the damping time of the feedback in addition to the coherent tune. Plans are outlined for hardware upgrades of the LHC transverse feedback system that will enable fast online processing of bunch-by-bunch, turn-by-turn data using Graphical Processing Units (GPU). By using GPUs we gain the ability to compute and store the spectrum of all bunches in real-time and the possibility to reconfigure test and deploy algorithms. This data acquisition and analysis architecture also allows changes to be made without disturbing the operation.

Poster TUPF29 [1.052 MB]

WEAL3

Diffraction Radiation Test at CesrTA for Non-Intercepting Micron-Scale Beam Size Measurement

target, radiation, electron, CLIC

619

L.M. Bobb, E. Bravin, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
T. Aumeyr, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
M.G. Billing, J.V. Conway
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L.M. Bobb
JAI, Egham, Surrey, United Kingdom

Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. DR can therefore be used to develop non-invasive diagnostic tools. To achieve the micron-scale resolution required to measure the transverse (vertical) beam size using incoherent DR in CLIC, DR in UV and X-ray spectral-range must be investigated. Experimental validation of such a scheme is ongoing at CesrTA at Cornell University, USA. Here we report on the test using 0.5 mm and 1 mm target apertures on a 2.1 GeV electron beam and 400 nm wavelength.

Slides WEAL3 [2.893 MB]

WEBL3

Wake Field Monitors in a Multi Purpose X Band Accelerating Structure

alignment, dipole, longitudinal, emittance

634

M.M. Dehler, S. Bettoni, B. Beutner, G. De Michele
PSI, Villigen PSI, Switzerland
G. De Michele
EPFL, Lausanne, Switzerland
G. De Michele
CERN, Geneva, Switzerland

In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. These feature integrated wake field monitors (WFMs), which are used to measure the alignment (offset and tilt) between structure and beam. One structure has recently been installed in the SwissFEL Injector Test facility (SITF) at PSI. The WFM front end electronics will be developed within the EuCard2 framework, so for the measurements described in this paper we used the raw WFM signals. We compare these measurements to the theoretical results obtained via an equivalent circuit model used in the design and numerical calculations. The beam tests show that by minimizing the WFM signals, the emittance dilution given by the transverse wakes, crucial because of the small aperture of the structure, is minimized as well.

Slides WEBL3 [1.668 MB]

WEPC05

The ELENA Beam Diagnostics Systems

antiproton, electron, pick-up, proton

664

G. Tranquille
CERN, Geneva, Switzerland

The Extra Low ENergy Antiproton ring (ELENA) to be built at CERN is aimed at substantially increasing the number of antiprotons to the low energy antiproton physics community. It will be a small machine which will decelerate low intensity beams (<4x10⁷) from 5.3 MeV to 100 keV and will be equipped with an electron cooler to avoid beam losses during the deceleration and to significantly reduce beam phase space at extraction. To measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and all the way to the experiments, many systems will be needed to ensure that the desired beam characteristics are obtained. Particular attention needs to be paid to the performance of the electron cooler which depends on reliable instrumentation in order to efficiently cool the antiprotons. This contribution will present the different monitors that have been proposed to measure the various beam parameters as well as some of the developments going on to further improve the ELENA diagnostics.

Poster WEPC05 [1.767 MB]

WEPC11

Radiation Resistance Testing of Commercial Components for the New SPS Beam Position Measurement System

radiation, SPS, beam-position, BPM

686

C. Deplano, J. Albertone, T.B. Bogey, J.L. Gonzalez, J.-J. Savioz
CERN, Geneva, Switzerland

A new Front-End (FE) electronics is under development for the SPS Multi Orbit POsition System (MOPOS). To cover the large dynamic range of beam intensities (70dB) to be measured in the SPS, the beam position monitor signals are processed using logarithmic amplifiers. They are then digitized locally and transmitted via optical fibers over long distances (up to 1km) to VME acquisition boards located in surface buildings. The FE board is designed to be located in the SPS tunnel, where it must cope with a radiation dose rate of up to 100 Gy per year. Analogue components, such as Logarithmic Amplifiers, ADC-Drivers and Voltage regulators, have been tested at PSI for radiation hardness, while several families of bidirectional SFP, both single-fiber and double-fiber, have been tested at both PSI and CNRAD. This paper gives a description of the overall system architecture and presents the results of the radiation hardness tests in detail.

Poster WEPC11 [3.299 MB]

WEPC44

Operation of Silicon, Diamond and Liquid Helium Detectors in the Range of Room Temperature to 1.9 Kelvin and After an Irradiation Dose of Several Mega Gray

DIAMOND, proton, LHC, beam-losses

791

C. Kurfuerst, M.R. Bartosik, B. Dehning, T. Eisel, M. Sapinski
CERN, Geneva, Switzerland
V. Eremin
IOFFE, St. Petersburg, Russia

At the triplet magnets close to the interaction regions of the LHC, the current Beam Loss Monitoring system is sensitive to the debris from the collision points. For future beams with higher energy and intensity, the expected increase in luminosity and associated increase of the debris from interaction products is expected to compete with any quench-provoking beam losses from the primary proton beams. In order to distinguish between the two, it is proposed to locate the detectors as close as possible to the superconducting coil. The detectors therefore have to be located inside the cold mass of the superconducting magnets in superfluid helium at 1.9 K. Past measurements have shown that in a liquid helium chamber, diamond and silicon detectors are promising candidates for cryogenic beam loss monitors. This contribution will show the results from new high irradiation beam measurements at both room temperature and 1.9 Kelvin to reveal the radiation tolerance of these different detectors.

WEPF07

Profile Grid Monitor and First Measurement Results at the MedAustron Accelerator

controls, feedback, ion, beam-transport

822

M. Repovz, A. Gyorgy, A. Kerschbaum, F. Osmic, S.M. Schwarz
EBG MedAustron, Wr. Neustadt, Austria
G. Burtin
CERN, Geneva, Switzerland

MedAustron is an ion beam therapy center located in Wiener Neustadt, Austria. The design is based on CERN’s Proton-Ion Medical Machine Study and the project is currently in the installation and commissioning phase. This paper summarizes the design, production and commissioning of MedAustron’s beam profile grid monitor. This monitor measures the beam profile in the low and medium energy beam transfer line where the beam dimensions can be as large as 100 mm. Reasonable position resolution is achieved with a harp consisting of 64 wires per plane and a pitch of up to 1.7 mm. Special effort was needed to produce such harps and bring the signal cables out of the vacuum. As the readout electronics has to cope with DC as well as pulsed beam all 128 wires are acquired simultaneously. This is achieved by integrating the charge during the “flat-top” of the beam pulse and storing it for serial transmission to the back end electronics for conversion. The high accuracy requires calibration of offset and amplification errors for every single channel. A NI PXI FPGA card controls the readout chain. The code for controlling the readout, including the graphical interface, is written in NI LabView.

WEPF09

Profile and Emittance Measurements at the CERN LINAC-4 3 MeV Test Stand

emittance, linac, transverse, rfq

826

F. Zocca, E. Bravin, M. Duraffourg, G.J. Focker, D. Gerard, U. Raich, F. Roncarolo
CERN, Geneva, Switzerland

A new 160 MeV H⁻ Linac named Linac-4 will be built at CERN to replace the old 50 MeV proton Linac. The ion source, the 3 MeV RFQ and the medium energy transport (MEBT) hosting a chopper, have been commissioned in a dedicated test stand. Wire grids and wire scanners were used to measure the transverse beam profile and a slit/grid emittance meter was installed on a temporary test bench plugged at the RFQ and MEBT exit in different stages. The emittance meter slit was also used as a scanning scraper able to reconstruct the transverse profile by measuring the transmission with a downstream current transformer. On the same measurement bench, a spectrometer in conjunction with a wire grid allowed measuring the energy spread of the particles. This paper summarizes the measurement results that allowed characterizing the 3 MeV beam and discusses the present understanding of monitor performance.

WEPF10

Wire Scanner Design for the European Spallation Source

linac, ESS, proton, diagnostics

830

B. Cheymol, A. Jansson, T.J. Shea
ESS, Lund, Sweden

The European Spallation Source (ESS), to be built in the south of Sweden, will use a 2 GeV superconducting LINAC to produce the world's most powerful neutron source with a beam power of 5 MW. The beam power is a challenge for interceptive beam diagnostics like wire scanner, the thermal load on intercepting devices implies to reduce the beam power in order to preserve the device integrity. For nominal operation, non-disturbing techniques for profile measurements are planned, while for the commissioning phase, accurate measurements and cross checking, wire scanners will be used. This paper describes the preliminary design of the wire scanner system in the normal conducing LINAC as well as in the superconducting LINAC.

WEPF28

Longitudinal Beam Diagnostic from a Distributed Electrostatic Pick-Up in CERN’s ELENA Ring

longitudinal, pick-up, antiproton, diagnostics

883

M.E. Angoletta, F. Caspers, S. Federmann, J.C. Molendijk, P.J. Pascal Jean, F. Pedersen, J. Sanchez-Quesada, L. Søby, M.A. Timmins
CERN, Geneva, Switzerland

The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Required longitudinal diagnostics include the intensity measurement for bunched and debunched beam and the measurement of Dp/p for a debunched beam to assess the electron cooling performance. A novel method for the calculation of these parameters is proposed for ELENA, where signals from the twenty electrostatic pick-ups (PU) used for orbit measurements will be combined to improve the signal-to-noise ratio. This requires that the signals be digitally down-converted, rotated and digitally summed so that the many electrostatic PUs will function as a single, distributed PU from to the processing system viewpoint. This method includes some challenges and will not be used as the baseline longitudinal diagnostics for the initial ELENA operation. This paper gives an overview of the hardware and digital signal processing involved, as well as of the challenges that will have to be faced.

WEPF29

The LHC Fast Beam Current Change Monitor

LHC, injection, FIR, beam-losses

887

D. Belohrad, J.M. Belleman, L.K. Jensen, M. Krupa, A. Topaloudis
CERN, Geneva, Switzerland

The modularity of the Large Hadron Collider’s (LHC) machine protection system (MPS) allows for the integration of several beam diagnostic instruments. These instruments have not necessarily been designed to have protection functionality, but MPS can still use them to increase the redundancy and reliability of the machine. The LHC fast beam current change monitor (FBCCM) is an example. It is based on analogue signals from fast beam current transformers (FBCT) used nominally to measure the LHC bunch intensities. The FBCCM calculates the magnitude of the beam signal provided by the FBCT, looks for a change over specific time intervals, and triggers a beam dump interlock if losses exceed an energy-dependent threshold. The first prototype of the FBCCM was installed in the LHC during the 2012-2013 run. The aim of this article is to present the FBCCM system and the results obtained, analyse its current performance and provide an outlook for the final system which is expected to be operational after the long LHC shutdown.

WEPF31

A FESA DAQ for Fast Current Transformer in SIS 18

synchrotron, longitudinal, SIS, pick-up

894

O. Chorniy, H. Bräuning, T. Hoffmann, H. Reeg, A. Reiter
GSI, Darmstadt, Germany

This contribution presents the development of the data acquisition (DAQ) system for the readout of fast beam current transformers (FCT) as installed in the GSI synchrotron SIS18 and as foreseen in several FAIR ring accelerators. Fast current transformers are reliable devices that offer a large analogue bandwidth and can therefore monitor bunch structures with high resolution. At appropriate sampling rates continuous measurements throughout repeated machine cycles lead to a large amount of raw data. The analysis of those raw data may range from simple bunch parameter calculations to complex longitudinal phase space reconstructions. Consequently, a new DAQ system must be carefully designed to allow for flexible acquisition modes or to allow for data reduction methods in special applications. The aims of the development are discussed and the status of the new DAQ is presented.

Poster WEPF31 [2.307 MB]

THBL2

The White Rabbit Project

controls, CDR, diagnostics, radio-frequency

936

J. Serrano, M. Cattin, G. Daniluk, E. Gousiou, M.M. Lipiński, E. Van der Bij, T. Włostowski
CERN, Geneva, Switzerland

White Rabbit (WR) is a multi-laboratory, multi-company collaboration for the development of a new Ethernet-based technology which ensures sub-nanosecond synchronisation and deterministic data transfer. The project uses an open source paradigm for the development of its hardware, gateware and software components. This article provides an introduction to the technical choices and an explanation of the basic principles underlying WR. It then describes some possible applications and the current status of the project. Finally, it provides insight on current developments and future plans.

Slides THBL2 [5.516 MB]