TUPB —  Poster Session 2   (15-Sep-15   16:00—18:00)
Paper Title Page
Development of Hardware of the Fast Orbit Feedback FPGA Controller Unit at the Australian Synchrotron.  
  • N.J. Basten, E. Joseph Vettoor, Y.E. Tan
    SLSA, Clayton, Australia
  • A. Michalczyk
    ASCo, Clayton, Victoria, Australia
  The design and construction of a controller unit for the fast Orbit Feedback system presented in this poster will be implemented on a Virtex-6 Xilinx FPGA platform. The controller will receive data from Libera electron Beam Position Processors, will connect with the control system via Ethernet interface and communicate with power supplies of the external corrector magnets via fibre optic links. The controller will have additional interfaces and ports for future developments of new diagnostic systems. It will also allow for unification of the controls interfaces saving development time in the future.  
poster icon Poster TUPB001 [1.734 MB]  
TUPB002 Fast Orbit Feedback System at SLSA 1
  • Y.E. Tan, N.J. Basten, T.D. Cornall, E. Joseph Vettoor
    SLSA, Clayton, Australia
  • A. Michalczyk
    ASCo, Clayton, Victoria, Australia
  • D.J. Peake
    The University of Melbourne, Melbourne, Victoria, Australia
  Since the end of commissioning of the facility in 2006, implementing topup (completed 2012) and fast orbit feedback have been top priority upgrades to improve the stability of the light source for users. The fast orbit feedback system is currently being implemented and will be commissioned in 2016. The feedback system has a star topology with an FPGA based feedback processor at its core. The system will utilises the existing 98 Libera Electron beam position processors, with Libera Grouping for data aggregation, as the source of postion data at 10 kHz. The corrections are calculated in a Xilinx Vertex 6 FPGA and is transmitted to 14 corrector power supplies in the 14 sectors. These power supplies are six-channel bipolar 1 Ampere and have been developed by a local company. The corrector magnets are tertiary coils on the existing sextupole magnets in the storage ring. This report shall present the design, results of Simulink simulations, the current status of implementation and future plans.  
FPGA for Fast Orbit Feedback at SLSA  
  • E. Joseph Vettoor, A. Michalczyk
    ASCo, Clayton, Victoria, Australia
  • T.D. Cornall, Y.E. Tan
    SLSA, Clayton, Australia
  The controller for the fast Orbit Feedback system will be implemented on a Virtex-6 Xilinx FPGA. The system will acquire the beam positions from Libera electron Beam Position Processors and compute the corrections for the power supplies, of the corrector magnets. The processing will be handled centrally by a single FPGA with a 30us constraint to meet the bandwidth requirements of the system and system will be built in a modular fashion to facilitate the use of developed modules for future FPGA projects.  
TUPB005 Advancements in the Management Measurements & Visualisation of NEC Beam Profile Monitors 1
  • D.T. Button, D.B. Garton, M.C. Mann
    ANSTO, Menai, New South Wales, Australia
  • S. Yan
    NI, Macquarie Park, New South Wales, Australia
  In DC ion beam tandem accelerator facilities commonly Helix Rotating wire Beam Profile Monitors (BPM) are used to monitor the shape and location of the beam. These BPM's are used in combination with a BPM Selection station which activates and conditions signals for display on an Oscilloscope for visualization. At ANSTO we have been developing an alternative system to allow management of concurrent off the shelf NEC BPM's, and to construct a 2D approximation of the particle beam based on programmable hardware and software. This paper will review the current status of the development, and the potential features which can be gained with this technological approach.  
TUPB006 Impedance Optimization of Sirius Stripline Kicker 1
  • H.O.C. Duarte, S.R. Marques
    LNLS, Campinas, Brazil
  Two approaches to design a transverse feedback (TFB) stripline kicker are well known in the accelerators community: one with bare strips in a tapered cavity and other whose shrouded strips are ended with parallel-plate capacitive gaps. This work presents a comparison between both models in terms of electromagnetic performance, proposes alternative solutions for increasing the gap capacitance and analyzes the performance of a hybrid stripline kicker design.  
poster icon Poster TUPB006 [2.369 MB]  
TUPB007 Multifunction Instrument Designs with Low Impedance Structures for Profile, Energy, and Emittance Measurements for LEReC at BNL 1
  • T.A. Miller, M. Blaskiewicz, A.V. Fedotov, D.M. Gassner, D. Kayran, J. Kewisch, M.G. Minty, I. Pinayev, P. Thieberger, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The low energy RHIC electron cooling (LEReC) upgrade project [1], being installed over the next two years will require a low impedance beam line so that the soft 1.6MeV electron beam will not be perturbed by induced electromagnetic fields, especially in the instrumentation chambers. Novel designs of the Profile Monitors, Emittance Slit Scanners and BPMs are presented along with Particle Studio simulations of the electron beam wake-field induced electric potentials. The design of a new instrument incorporating a button beam position monitor (BPM) and YAG screen profile monitor in the same measuring plane is presented as part of a method of measuring beam energy with an accuracy of 10-3.
[1] D. Gassner, et al, TUPF24, proceedings of IBIC2013, Oxford, UK
poster icon Poster TUPB007 [9.428 MB]  
TUPB008 Beam Diagnostics of the LIPAC Injector With a Focus on the Algorithm Developed for Emittance Data Analysis of High Background Including Species Fraction Calculation 1
  • B. Bolzon, N. Chauvin, S. Chel, R. Gobin, F. Senée, M. Valette
    CEA/IRFU, Gif-sur-Yvette, France
  • J. Knaster, Y. Okumura
    IFMIF/EVEDA, Rokkasho, Japan
  • K. Shinto
    Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
  To prove the feasibility of the IFMIF accelerators concept, the EVEDA phase will commission in Japan the LIPAC accelerator, which will deliver a 125 mA/9 MeV CW deuteron beam. LEDA already managed 100 mA in CW at 6.7 MeV in 2000. The different subsystems of LIPAC have been designed and constructed mainly by European labs with the injector developed by CEA-Saclay. This injector must deliver a 140 mA/100 keV CW deuteron beam at 99% D+ ratio, which is produced by a 2.45 GHz ECR ion source. The low energy beam transport line is based on a dual solenoid focusing system to transport the beam and to match it into the RFQ. The normalized RMS target emittance at the RFQ entrance is targeted to be within 0.25π mm·mrad. This article describes the diagnostics installed in the LEBT to measure beam parameters such as intensity, profile, emittance, species fraction and degree of space charge compensation. The article also focuses on the algorithm developed to analyze emittance data of high background from an Allison scanner. Species fractions (D+, D2+, D3+) using mass separation technique were also calculated with the Allison scanner installed between the two solenoids in a first stage.  
poster icon Poster TUPB008 [1.122 MB]  
TUPB009 A New Beam Angle Interlock at Soleil 1
  • N. Hubert, Y.-M. Abiven, L. Cassinari, L. Chapuis, F. Dohou, M.E. El Ajjouri, A. Loulergue, O. Marcouillé, P. Monteiro, L.S. Nadolski, D. Pédeau, P. Rommeluère
    SOLEIL, Gif-sur-Yvette, France
  Anatomix and Nanoscopium beamlines are collecting photons generated by two 5.5 mm gap in-vacuum insertion devices installed in a canted straight section. Simultaneous operation of those two beamlines requires particular precautions in terms of alignment of the electron (and photon) beam in the undulators. With the high stored beam current (500 mA), any mis-steering in the upstream undulator could quickly damage the downstream one. Using the classical beam position interlock to guarantee the undulators protection would have constrained too much the operation due to very restrictive position thresholds. Then the machine protection system has been modified to incorporate a new interlock based on the electron beam angle combining two BPM readings. A description of the system and its performances will be presented.  
TUPB010 Digital Processing of Pick-up Signals for Position and Tune Determination 1
  • R. Singh, P. Forck, P. Kowina, A. Reiter
    GSI, Darmstadt, Germany
  With the advent of fast high resolution Analog to Digital Converters (ADCs) and Field Programmable Gate Arrays (FPGAs), 'all digital systems' for pick-up data processing to calculate position and tune have become commonplace. The flexibility of these digital systems is very advantageous since it permits the change of position determination algorithms based on beam conditions, accelerator operation modes and measurement requirements. This contribution compares the frequently used position determination algorithms in terms of measurement variance, bias, robustness and computational complexity using simple analytical model. The analytical model is compared to the beam data to evaluate its applicability and conclusions on the optimum position estimator are derived.  
TUPB011 Micron-Scale Vertical Beam Size Measurements Based on Transition Radiation Imaging With a Schwarzschild Objective 1
  • G. Kube, S. Bajt
    DESY, Hamburg, Germany
  • I.A. Artyukov
    LPI, Moscow, Russia
  • W. Lauth
    IKP, Mainz, Germany
  • A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
    TPU, Tomsk, Russia
  Funding: The work was partially supported by the Russian Ministry of Education and Science within the program Nauka Grant No. 3.709.2014/K
Transverse beam profile diagnostics in the case of micron-scale beam sizes from modern electron accelerators are a challenging task. Backward transition radiation (BTR) imaging in the visible spectral region which is usually applied is close to the diffraction limit, i.e. the measured beam image is dominated by the point-spread function (PSF) [*, **]. In order to improve the resolution and to measure sub-micron beam sizes, the influence of the PSF should be decreased which depends not only on the wavelength, but also on optical aberrations. This can be realized by imaging in the EUV spectral region using a multilayer Schwarzschild objective which is free of some types of aberrations [***]. A first test experiment devoted to micron-scale beam size measurements has been carried out at the Mainz Microtron MAMI (Germany), using visible BTR and a Schwarzschild objective. This report summarizes first results of PSF dominated imaging with vertical beam sizes in the order of a few microns. Possibilities to extend the use of a Schwarzschild objective in future experiments with EUV BTR will be discussed.
* P. Karataev et al., PRL 107 (2011) 174801.
** G. Kube et al., proc. of IPAC13 (2013) MOPME010.
*** I.A. Artyukov et al, Opt. Eng. 39 (2000) 2163.
TUPB012 Transverse Beam Profile Imaging of Few-Micrometer Beam Sizes Based on a Scintillator Screen 1
  • G. Kube, S. Bajt
    DESY, Hamburg, Germany
  • I.A. Artyukov
    LPI, Moscow, Russia
  • W. Lauth
    IKP, Mainz, Germany
  • A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
    TPU, Tomsk, Russia
  Funding: This work was partly supported by the by the Russian Ministry of Education and Science within the program 'Nauka' Grant No. 3.709.2014/K.
Standard beam profile measurements of high-brightness electron beams based on optical transition radiation (OTR) may be hampered by coherence effects induced by the micro-bunching instability which render a direct beam imaging impossible. As consequence, for modern linac based 4th generation light sources as the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. However, the resolution of a scintillator based monitor is limited due to intrinsic material properties and the observation geometry [*,**]. In this report we present the results of beam size measurements in the order of a few microns using a LYSO:Ce scintillator and discuss the possible achievable resolution.
[*] G. Kube et al., Proc. IPAC'12 (2012) WEOAA02.
[**] B. Walasek-Höhne and G. Kube, Proc. DIPAC'11 (2011) WEOB01.
Simulation of Two-Dimensional PSF-Dominated Beam Profile Images Based on OTR and the Influence of De-Focusing  
  • G. Kube
    DESY, Hamburg, Germany
  • A. Potylitsyn, L.G. Sukhikh
    TPU, Tomsk, Russia
  Funding: This work was partly supported by the by the Russian Ministry of Education and Science within the program 'Nauka' Grant No. 3.709.2014/K.
Transverse beam profile diagnostics in electron accelerators is usually based on direct imaging of a beam spot via visible radiation (transition or synchrotron radiation). In this case, the fundamental resolution limit is determined by radiation diffraction in the optical system. A method to achieve a resolution beyond the diffraction limit is to perform point spread function (PSF) dominated imaging, i.e. the recorded image is dominated by the resolution function of a point source (single electron). With knowledge of the PSF, the true image (beam spot) can be reconstructed. In the case of classical OTR imaging however, the radiation is emitted from a tilted screen surface, and a part of the image will be out of focus. While this de-focusing influence can usually be neglected, it was observed already in the case of sub-micron beam size measurements. This paper presents a model to calculate PSF-dominated beam profile images based on optical transition radiation from a tilted screen surface, taking into account the influence of de-focusing.
TUPB014 Development Status and Performance Studies of the New MicroTCA Based Button and Strip-line BPM Electronics at FLASH 2 1
  • B. Lorbeer, N. Baboi, H.T. Duhme, F. Schmidt-Föhre, K. Wittenburg
    DESY, Hamburg, Germany
  The FLASH (Free Electron Laser in Hamburg) facility at DESY (Deutsches Elektronen-Synchrotron) in Germany has been extended by the new undulator line FLASH2 providing twice as many experimental stations for users in the future. After the acceleration of the electron bunch train up to 1.2GeV in FLASH, a part of the beam can be kicked into FLASH2, while the other is going to the old undulator line of FLASH I. The commissioning phase of FLASH2 started in early 2014 and is continued parasitically during user operation in FLASH1. One key point during first beam commissioning is the availability of standard diagnostic devices such as Beam Position Monitors (BPMs). In the last couple of years new electronics for button and strip-line BPMs have been developed, based on the MTCA.4 standard. This new Low Charge BPM (LCBPM) system is designed to work with bunch charges as small as 100 pC in contrast to the old systems at FLASH initially designed for bunch charges of 1nC and higher. This paper summarizes the performance of the BPM system and discusses the applied methods based on beam based correlation techniques to study the system.  
TUPB015 Development of New Beam Position Monitors at COSY 1
  • F. Hinder, H. Soltner, F. Trinkel
    FZJ, Jülich, Germany
  • H.-J. Krause
    Forschungszentrum Jülich, Peter Gruenberg Institut, Jülich, Germany
  Electric Dipole Moments (EDM) violate parity and time reversal symmetries. Assuming the CPT-theorem, this leads to CP violation, which is needed to explain the matter over antimatter dominance in the Universe. Thus, a non-zero EDM is a hint to new physics beyond the Standard Model. The JEDI collaboration (Jülich Electric Dipole moment Investigations) has started investigations of a direct EDM measurement of protons and deuterons at a storage ring. To measure a tiny EDM signal with high precision, systematic effects have to be controlled to the same level. One way of controlling systematic effects is the use of new Beam Position Monitors. The idea is based on the usage of magnetic pick-ups in a Rogowski coil configuration. The main advantage of the coil design is the high response to a high frequency signal, the particle bunch frequency, and the compactness of the coil itself. In a first step the BPMs will be benchmarked in a laboratory test system. In the next step the calibrated BPMs will be installed and tested at the conventional storage ring COSY (Cooler Synchrotron) at Jülich. At the conference first measurement results and the upcoming developments will be presented.  
poster icon Poster TUPB015 [1.737 MB]  
Upgrade of the Beam Profile Monitoring System in the Injection Beam Line of COSY  
  • K. Reimers, C. Böhme, V. Kamerdzhiev
    FZJ, Jülich, Germany
  • J.L. Conradie, M.A. Crombie, H.W. Mostert
    iThemba LABS, Somerset West, South Africa
  The 183 m long synchrotron and storage ring COSY is fed by the cyclotron Julic. The 95 m long injection beam line (IBL) transports H-/D- ions which are injected into the ring via a multi-turn stripping injection. 8 profile monitoring stations are installed in the IBL. Each station contains two harps having 39 wires at 1mm spacing. Each harp is read out by a multichannel pico-amperemeter electronics designed by iThemba LABS, South Africa, delivering profile data to the COSY control system. The technical details of the upgrade are described and first results are presented.  
TUPB017 Studies for a BPM Upgrade at COSY 1
  • C. Böhme, M. Bai, F. Hinder, V. Kamerdzhiev, F. Trinkel
    FZJ, Jülich, Germany
  For the planned Electric Dipole Moment (EDM) precursor experiment at the COSY synchrotron and storage ring an accurate control of the beam orbit is crucial. The required beam position measurement accuracy demands an upgrade of the BPM readout electronics. The BPM system currently in operation is described. The required performance and the possible upgrade scenarios are discussed.  
TUPB018 Compact and Complete Beam Diagnostic System for HCI at IUAC 1
  • R.V. Hariwal, S. Kedia, R. Mehta
    IUAC, New Delhi, India
  • H.K. Malik
    Indian Institute of Technology, New Delhi, India
  • V.A. Verzilov
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  Funding: University Grants Commission, India
Design efforts result into the fabrication of a compact and complete beam diagnostic system for High Current Injector (HCI) accelerator system at Inter-University Accelerator Centre (IUAC), New Delhi, India. HCI is an upcoming accelerator facility and will be used as an injector to the existing SC-LINAC. It consists of high temperature superconducting Electron Cyclotron Resonance (HTS-ECR) ion source, normal temperature Radio Frequency Quadrupole (RFQ), IH-type Drift Tube Linear (DTL) resonators and low beta superconducting quarter wave resonator cavities to accelerate heavy ions having A/q ≤ 6. The diagnostic system is especially designed and fabricated to get the complete beam information like current, profile, position, transverse and longitudinal emittances, bunch length and energy of incident ion beam at the entrance of DTL resonators. The compactness is preferred to minimize the transverse and longitudinal emittance growth at the entrance of DTL resonators. Various beam parameters of heavy ion beams at different energy have been carried out to validate the design and fabrication of the system. Here, the design, fabrication and various test results are presented.
poster icon Poster TUPB018 [3.739 MB]  
TUPB019 Design and Development of Configurable BPM Readout System for ILSF 1
  • M.Sh. Shafiee, M. Jafarzadeh, J. Rahighi
    ILSF, Tehran, Iran
  • A.H. Feghhi
    Shahid Beheshti University, Tehran, Iran
  A configurable electronic system has been developed for button BPMs readout in the storage ring of Iranian Light Source Facility (ILSF). This system calculates the beam position through the output voltage of BPMs. Output signals of BPMs pass through a 500 MHz and 50ohm front-end for noise filtering and also gain control purposes. Then the signal is digitized based on under sampling method by a 130MHz ADC for further analysis in FPGA. Safe dynamic range of 0dBm to -90 dBm can be covered by this electronic system with white noise measured to be around -110dBm. Trigger for this electronic is 2-10Hz as Slow data acquisition for Slow orbit feedback system and 4-10KHz as Fast data acquisition for fast orbit feedback system. This paper describes the design, analysis, and measurements of the developed electronic system.  
poster icon Poster TUPB019 [1.722 MB]  
TUPB020 Long-Term Stability of the Beam Position Monitors at SPring-8 1
  • T. Fujita, H. Dewa, M. Masaki, S. Matsubara, S. Sasaki, S. Takano
    JASRI/SPring-8, Hyogo-ken, Japan
  • H. Maesaka, Y. Otake
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  At the SPring-8 storage ring, the renewal of BPM electronics in 2006 has improved orbit feedback resolution *. However, a stability issue of the whole BPM system, including the buttons, the cables and the electronics, remains to be settled for long-term stability of the beam orbit. The BPM in the present SPring-8 has gain imbalances among 4 electrode channels, which result in large offsets (~1 mm). The imbalances are routinely corrected in accordance with a beam-based measurement **. But, the offset error increases close to 100 um during the operation, because of the imbalance fluctuations. Major origin of the imbalances is standing waves caused by reflections in BPM cables. As a countermeasure for the imbalance issue, isolators to mitigate the standing waves were equipped. They significantly reduced the imbalances, but not sufficient to completely suppress the imbalance fluctuations. The requirement of stability for the BPM system for the upgrade plan of SPring-8 is going to be more stringent. We started extensive survey to find the sources of fluctuations of the gain imbalances in order to achieve long-term stability of the BPM system applicable to the planned SPring-8 upgrade.
* S. Sasaki, T. Fujita et al., Proc. of the DIAPC 2007, Venice, Italy, (2007) p. 114
** M. Masaki et al., Proc. of the 11th Symp. on Accel. Sci. and Technol., (1997), p.83.
TUPB021 Characterization of the SR Visible Beam Polarization State at SPEAR3 1
  • C.L. Li
    East China University of Science and Technology, Shanghai, People's Republic of China
  • W.J. Corbett
    SLAC, Menlo Park, California, USA
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  Synchrotron radiation has the well-known property of horizontal field polarization in the midplane with increasingly elliptical polarization in the vertical plane. By measuring the beam intensity transmitted through a linear polarizer, it is possible to characterize the beam polarization state, determine the Stokes' parameters and solve for the beam polarization ellipse in the visible portion of the SR spectrum. The results can be compared with Schwinger's equations for synchrotron radiation taking into account the effect of extraction mirrors.  
poster icon Poster TUPB021 [1.493 MB]  
TUPB023 High Position Resolution BPM Readout System with Calibration Pulse Generators for KEK e+/e Linac 1
  • F. Miyahara, K. Furukawa, M. Satoh, Y. Seimiya, T. Suwada
    KEK, Ibaraki, Japan
  • R. Ichimiya
    JAEA, Aomori, Japan
  • H.S. Saotome
    Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
  The KEK e+/e injector linac will be operated in multiple modes for the electron beam injection to 3 independent storage rings, SuperKEKB HER, Photon Factory (PF) Ring and PF-AR, and the positron beam injection into the damping ring and the SuperKEKB LER. The operation modes can be switched every 20 milliseconds. The injector linac is under upgrade for the SuperKEKB, where the required resolution of beam position measurement is less than 10 micrometer. However, the current system based on oscilloscopes for stripline beam position monitors (BPMs) has the position resolution of 50 micrometers approximately. Thus, we have developed a new BPM readout system with narrow band pass filter, 16-bit, 250 MSa/s ADCs and calibration pulse generators. The system is based on VME standard and the beam position is calculated by FPGA on board. The new system has the position resolution of 3 micrometer and wide dynamic range from 0.1 to 10 nC/bunch. The calibration pulse follows every position measurement. The calibration pulse is used for the gain correction and the integrity monitor of the cable connection. We will report details of the system.  
TUPB024 Beam Halo Measurement Utilizing YAG:Ce Screen 1
  • T. Naito, T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  Funding: Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
At the ATF2 project, we are aiming to produce an extremely small beam having a vertical beam size of 37 nm. The beam halo surrounding of beam core will make a background for the beam size measurement using the Laser interferometer beam size monitor. The understanding of beam halo distribution is important for measurement of the beam size at the final focus point of ATF2. In order to measure the beam halo distribution, we developed a beam halo monitor based on fluorescence screen. A YAG:Ce screen, which has 1 mm slit in the center is set in the beam line. The image on fluorescence screen is observed by imaging lens system and CCD camera. In this configuration, the beam in the core will pass through the slit. The beam in the surrounding halo will hit the fluorescence screen, and we can observe the distribution of beam halo. The intensity contrast of beam halo to the beam core is measured by scanning the beam position for the fixed fluorescence screen position. The results of observation of beam halo are presented.
TUPB025 Design of Coded Aperture Optical Elements for SuperKEKB X-ray Beam Size Monitors 1
  • E. Mulyani
    Sokendai, Ibaraki, Japan
  • J.W. Flanagan
    KEK, Ibaraki, Japan
  We describe the design of coded aperture optical elements for the SuperKEKB x-ray beam size monitors. X-ray beam profile monitor are being installed in each ring of SuperKEKB (LER and HER) to provide high resolution bunch-by-bunch, turn-by-turn measurement capability for low emittance tuning, collision tuning and instability measurements. We use two types of optical elements, single-slit (pinhole) and multi-slit optical elements (coded apertures, CA). CA imaging offers greater open aperture than a single pinhole, for greater photon throughput and better statistical resolution for single-shot measurements. X-rays produced by a hard-bend magnet pass through a pinhole or CA optical element onto a detector. The resolution is obtained by calculating the differences between the images recorded by the detector for various simulated beam sizes, for a given number of photons. The CA elements that we have designed for use at SuperKEKB are estimated to provide 1.25-2.25 microns resolution for 10-25 microns of vertical beam sizes at 1 mA bunches. We present the design principle and optimizing process used to optimize the resolution at various beam sizes for SuperKEKB.  
poster icon Poster TUPB025 [6.145 MB]  
Machine Stability Analysis by Pulse Based Data Archiver of the J-PARC RCS  
  • N. Hayashi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  The J-PARC RCS (Rapid-Cycling proton Synchrotron) runs with repetition rate of 25 Hz. The beam intensity of current monitors and beam loss monitors (BLM) data are archived for all pulses and they could be analyzed to study the machine stability. In addition BPM data are also recorded in regularly (2 seconds with every minutes) and particularly in case of the RCS MPS, the last several hundreds BPM data are recorded. We will report a few examples, in the case of magnet feedback problem or vacuum problem, how the BPM or BLM behaves.  
TUPB027 Bunch Length Analysis of Negative Hydrogen Ion Beam in J-PARC Linac 1
  • A. Miura, N. Hayashi
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Fukuoka
    University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
  • Y. Liu
    KEK/JAEA, Ibaraki-Ken, Japan
  • T. Maruta
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Miyao
    KEK, Ibaraki, Japan
  We used bunch shape monitors (BSMs) to measure the longitudinal bunch length of a negative hydrogen ion beam in the J-PARC linac. Because we experienced a vacuum degradation to suspend a beam operation during the BSM operations, BSMs were once dismounted for vacuum conditioning. We installed one BSM again in the beam line with additional vacuum equipment. We stared to measure the 191-MeV beam again to tune the buncher amplitude after checking a functioning BSM by comparing its results with those of a simulation. To evaluate the measurement errors with peak beam current increasing, we observed waveforms with various beam currents. Therefore, the RMS bunch length depends on the peak beam current and the bending at the pulse head grows with the peak beam current. Furthermore, to avoid the thermal stress, we compared the data taken at an off-center beam with the ones taken at an on-center beam, because a target wire will be exposed to a higher peak beam current. In this study, we introduced the peak beam current dependence of the bunch length waveforms, and an effect of on-/off-centering of the wire position. Finally, the new buncher tuning method using one BSM is discussed.  
TUPB030 Measurements of Beam Halo by Wire Scanner Monitor 1
  • H. Jiang
    TUB, Beijing, People's Republic of China
  • P. Li, T.G. Xu
    IHEP, Beijing, People's Republic of China
  A wire scanner is used in the beam halo experiment at the Institute of High Energy Physics (IHEP) to measure the beam halo for the study of beam halo dynamics. The beam energy in the FODO transport line is 3.5 MeV and the peak current is 24 mA. Firstly we get the emittance value for the vertical and the horizontal plane respectively by measuring the matched beam. Then we measure the beam halo of the mismatched beam.  
poster icon Poster TUPB030 [0.344 MB]  
Beam Profile Detector Measurements with a Non-Destructive Ionization Position Monitor (IPM) at IMP  
  • H.M. Xie
    IMP/CAS, Lanzhou, People's Republic of China
  An accelerator-driven subcritical system (ADS) project was launched in China in 2011. The driver linac is designed to produce a 10 mA beam current of high energy protons at 1.5 GeV in continuous wave operation mode. To meet the extremely high power and intense beam requirements of the accelerator, non-destructive monitors for the beam transverse profile are required for this proton linac. Taking advantage of the residual gas as active material, the Ionization Position Monitor (IPM) produces charged ions from the interaction between incident ions and gas molecules for transverse profile measurements. The components of this non-destructive method are a metal electrostatic field plate, aμchannel plate and a phosphor coated screen and CCD camera. The spatial resolution can be optimized to 0.1 mm with a CCD while the time resolution is poorer than with a photodiode as signal collector. The profile detection experiments with the IPM were done in the synchrotron of Heavy Ion Research Facility of Lanzhou (HIRFL), later the IPM will be installed in ADS linac. The experimental results and details will be presented in this paper.  
poster icon Poster TUPB032 [1.280 MB]  
Construction and Measurement of the Emittance System and the Profile System  
  • Z. Xue
    IMP/CAS, Lanzhou, People's Republic of China
  The software part of the Emittance System and the Profile System mainly use NI CRIO equipment. It is made of a Crio chassis (such as 9024), a data acquisition card (for example 9223,9215) and an encoder card (9411). The system uses the electric machinery from Kollmorgen to move the hardware. At the same time, we use NI equipment to provide software control. The probe was designed in-house and constructed by an external company. This system has been used to measure the beam profile at IMP.  
TUPB035 Bunch-by-Bunch Study of the Transient State of Injection at the SSRF 1
  • Z.C. Chen, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
  Funding: National Natural Science Foundation of China (No. 11305253)
High current and stable beams are preferred to a light source, so the suppression of the oscillations due to the frequent injections during top-off operations get the attention at the Shanghai Synchrotron Radiation Facility (SSRF). To evaluate the possibility of further optimizations, a bunch-by-bunch position monitor is used to study the behavior of the injected bunch. The injected part is isolated from the stored one by decomposing the position matrix of all the bunches in the storage ring. Frequency feature, motion lifetime and other characteristic parameters of the injection mode have been compared with those of the stored mode.
poster icon Poster TUPB035 [0.563 MB]  
TUPB036 Progress of Cavity Beam Position Monitor at SXFEL 1
  • L.W. Lai, Z.C. Chen, Y.B. Leng, Y.B. Yan, L.Y. Yu, R.X. Yuan, W.M. Zhou
    SSRF, Shanghai, People's Republic of China
  Shanghai Soft X-ray FEL Test Facility (SXFEL) has started the infrastructure construction in 2015. All beam diagnostic systems are under processing and measurement, including C-band Low-Q cavity BPMs. This paper presents the progress of the cavity BPM system, including design and the measurements on a lab platform. Measurements shown that the cavity BPM frequency is 4.7GHz±8MHz, and the complete test platform verify that the cavity BPM system, which including signal processing electronics can work as expected.
* Work supported by National Natural Science Foundation (No. 11305253, 11375255)
TUPB037 Interferometer Data Analyzing Using the PCA Method at SSRF 1
  • Y.B. Leng, H.J. Chen, J. Chen, Z.C. Chen, Y.B. Yan
    SSRF, Shanghai, People's Republic of China
  An SR interferometer, which was used to monitor the transverse beam size in the SSRF ring, had been implemented and put into operation since 2009. The direct projection and curve fitting was adopted for raw image data processing. Any CCD alignment error could introduce some beam size measurement error in this case. Using primary component analyzing (PCA) method to process raw image data, the horizontal and vertical distribution information can be decoupled and the misalignment information of CCD can be derived. Beam experiment results will be discussed in this paper.  
TUPB041 Development of Capacitive Linear-Cut Beam Position Monitor for Heavy-Ion Synchrotron of KHIMA Project 1
  • J.G. Hwang, S.Y. Noh
    KIRAMS/KHIMA, Seoul, Republic of Korea
  • P. Forck
    GSI, Darmstadt, Germany
  • C. Kim
    PAL, Pohang, Kyungbuk, Republic of Korea
  • T.K. Yang
    KIRAMS, Seoul, Republic of Korea
  particles for the carbon beams and ~ ∼  2.07 × 10zEhNZeHn for the proton beams, the linear-cut beam position monitor is adopted to satisfy the position resolution of 100 μm and accuracy of 200 μm with the linearity within the wide range. In this paper, we show the electromagnetic design of the electrode and surroundings to satisfy the resolution of 100 μm, the criteria for mechanical aspect to satisfy the position accuracy of 200 μm, the measurement results of position accuracy and calibration by using wire test-bench, and the beam-test results with long ( ∼  1.6 μs) electron beam in pohang accelerator laboratory (PAL).  
TUPB043 Development of a Scintillation Screen Monitor for Transverse Ion Beam Profile Measurment at the Khima Project 1
  • S.Y. Noh, S.D. Chang, J.G. Hwang
    KIRAMS/KHIMA, Seoul, Republic of Korea
  • G. Hahn, T.K. Yang
    KIRAMS, Seoul, Republic of Korea
  The scintillation screen monitor measures transverse profile of ion beam in beam transport line. The Korea Heavy Ion Medical Accelerator Project (KHIMA) has developed a scintillation screen monitor in the high energy beam transport (HEBT) line. The images of each beam pulse were recorded by CCD camera and evaluated the beam properties by the LabVIEW-based in-house program in real time. We designed a scintillation screen monitor using phosphor screen, P43. In order to investigate the limits of scintillating screen during beam profile monitoring at low intensity, we designed a remote control device of iris for the incoming light adjustment to the CCD camera. In this paper, we present details of the image processing system using the LabVIEW and the beam profile measurement results from the in-beam test.  
Using Incoherent and Coherent Polarization Radiation as a Diagnostic of the Transverse Beam Size  
  • D.Yu. Sergeeva, A.A. Tishchenko
    MEPhI, Moscow, Russia
  Polarization radiation (diffraction radiation, Smith-Purcell radiation, transition radiation) can be a good diagnostic for sub-micron beam measurements. It is the so-called 'form-factor' of the beam that contains information about beam size. It represents the sum of two parts corresponding to the coherent and incoherent radiation [1]. Contrary to general opinion the incoherent part does not always equal unity [1]. It was mentioned in Ref. [2]. We give a theoretical description of the incoherent and coherent parts of the form-factor both for Gaussian and uniform distribution of ultra-relativistic particles in the bunch [1,3]. We show that the incoherent part depends on the transverse size of the beam, and dependence is not the same for different distributions. The possible role of the incoherent part of the form-factor of the bunch for different parameter is discussed.
1.D.Yu.Sergeeva, A.A.Tishchenko et al., NIM B (2013)
2.J.H. Brownell et al., PRE (1998); G. Doucas et al., PR STAB (2002)
3.D.Yu.Sergeeva et al., Proc. of FEL 2014, TUP013
EUV, X-ray Diffraction and Smith-Purcell Radiation as a Base for Non-Invasive Sub-Micron Beam Diagnostics  
  • A.A. Tishchenko, D.Yu. Sergeeva
    MEPhI, Moscow, Russia
  Developing sub-micron beam diagnostics is a vital problem for modern accelerators and colliders like CLIC, ILC, SLAC, DESY. High energy of the particles leads to requirement of the non-invasive diagnostics; because of small beam size the high resolution is required. The accuracy of resolution is limited to the wavelength because of the diffraction (Rayleigh) limit. All these problems can be solved with help of diagnostics based on incoherent and short-wavelength diffraction radiation (DR). We suggest DR and Smith-Purcell radiation of EUV and X-ray ranges as an instrument for submicron non-invasive beam diagnostics, proceeding from the developed theoretical description [1]. We construct theory of EUV and X-ray DR and SPR from ultra-relativistic beams for both uniform and Gaussian distributions of the particles [2]. The theory contains the case of beam skimming the target [2], which leads to mixing DR and transition radiation; the case of oblique incidence of the beam to the target [3], which leads to the conical effect in spatial distribution of DR and allows counting the divergence of the beam. Also, we describe analytically and analyse the incoherent form-factor of the beam.
1.A.A.Tishchenko et al.,PRE (2004); D.Yu.Sergeeva, A.A.Tishchenko et al., NIM B (2013)
2.D.Yu.Sergeeva, A.A.Tishchenko, Proc.of FEL 2014, TUP013
3.D.Yu.Sergeeva, A.A.Tishchenko et al., PR STAB (2015)
TUPB046 Integration of the Diamond Transverse Multibunch Feedback System at ALBA 1
  • A. Olmos, U. Iriso, J. Moldes, F. Perez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • M.G. Abbott, G. Rehm, I.S. Uzun
    DLS, Oxfordshire, United Kingdom
  A Transverse Multi-Bunch Feedback system (TMBF) has been commissioned at the ALBA storage ring for stabilization of the beam instabilities. The system is based on the Libera Bunch-By-Bunch electronics, controlled using a specific software developed at Diamond Light Source. This system refurbishes the existing FPGA code to include several features for machine studies, like fast and precise tune measurements using a Phase Locked Loop, sequences of grow-damp experiments that allow measuring damping rates on a mode-by-mode basis, and precise bunch cleaning. We describe the TMBF system and the integration of the control software into the ALBA machine. Finally we show examples of beam stabilization and machine studies using this system.  
TUPB047 Electrostatic finite-element code to study geometrical nonlinear effects of BPMs in 2D 1
  • A.A. Nosych, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • J. Olle
    UAB, Barcelona, Spain
  We have developed a 2D finite element-based software for Matlab to study non-resonant effects in BPMs of arbitrary geometry, in particular the geometric nonlinearities. The developed code called BpmLab utilizes an open-source tetrahedral mesh generator DistMesh, combined with a short implementation of FEM with linear basis functions to find the electrostatic field distribution for boundary electric potential excitation. The BPM response as a function of beam position is calculated in a single simulation for all beam positions using the potential ratios, according to the Green's reciprocity theorem. The code offers ways to correct the geometrical nonlinear distortion, either by polynomials or by direct inversion of the electrode signals through numerical optimization. This work is an overview of the BpmLab capabilities to date, including its extensive benchmarking and validation against other methods  
poster icon Poster TUPB047 [8.209 MB]  
TUPB048 Measurements and Calibration of the Stripline BPM for the ELI-NP facility with the Stretched Wire Method 1
  • A.A. Nosych, C. Colldelram, A. Crisol, U. Iriso, A. Olmos
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • F. Cioeta, A. Falone, A. Ghigo, M. Serio, A. Stella
    INFN/LNF, Frascati (Roma), Italy
  • A. Mostacci
    Rome University La Sapienza, Roma, Italy
  A methodology has been developed to perform electrical characterization of the stripline BPMs for the future Gamma Beam System of ELI Nuclear Physics facility in Romania. Several prototype units are extensively benchmarked and the results are presented in this paper. The BPM sensitivity function is determined using a uniquely designed motorized test bench with a stretched wire to measure the BPM response map. Here, the BPM feedthroughs are connected to Libera Brilliance electronics and the wire is fed by continuous wave signal, while the two software-controlled motors provide horizontal and vertical motion of the BPM around the wire. The electrical offset is obtained using S-parameter measurements with a Network Analyzer (via the "Lambertso" method) and is referenced to the mechanical offset.  
poster icon Poster TUPB048 [4.906 MB]  
TUPB049 Limitations and Solutions of Beam Size Measurements via Interferometry at ALBA 1
  • L. Torino, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  The interferometry beamline at ALBA had several limitations which have been overcome over the past years until currently, beam size measurements are successfully performed using this technique. The main limitation has been related to vibrations in the light wavefront transportation along the beamline. Several counter-measures have been taken to overcome these limitations, related both to the software analysis and the mechanical setup, where the conventional double slit system is substituted by a double pinhole in order to obtain more light and a better interferogram. This report describes the current interferometry setup at ALBA, and show some results.  
poster icon Poster TUPB049 [1.073 MB]  
TUPB051 Design of a New Super-heterodyne MicroTCA.4 BPM and LLRF Rear Transition Module (RTM) for the European Spallation 1
  • A. Young
    SLAC, Menlo Park, California, USA
  • H. Hassanzadegan
    ESS, Lund, Sweden
  Funding: Work supported by U.S. Department of Energy under Contract Numbers DE-AC02-06CH11357, DE-AC02-76SF00515, and CRADA 13-219C with the European Spallation Source AB
The 5MW European Spallation Source (ESS) is a long pulsed source based on a high power superconducting LINAC. In order to achieve this high level of performance, the beam position measurement system needs to measure the beam position, phase and intensity in all foreseen beam modes with a pulse rate of 14 Hz, duration of 2.86 ms and amplitude ranging form 5 mA to 62.5 mA. We have designed a general purpose Beam Position Monitor (BPM) front-end electronics that has a dynamic range of 70dB. The front-end uses the MicroTCA (Micro Telecommunication Computing Architecture) for physics platform that consists of a 16-bit 125 MSPS ADC module (SIS8300L/2 from Struck) that uses the Zone 3 A1.1 classification for the RTM. This paper will discuss the design of this new RTM that includes eight channels of super-heterodyne receivers, two channels of DC-coupled inputs to measure klystron voltage and current, one vector modulator that modulates the LLRF output. The RTM communicates with the AMC FPGA using a QSPI interface over the zone 3 connection.
poster icon Poster TUPB051 [4.058 MB]  
TUPB052 Wire Scanners and Vibrations - Models and Measurements 1
  • J. Herranz, B. Dehning, E. Effinger, J. Emery, A. Guerrero, C. Pereira
    CERN, Geneva, Switzerland
  • A. Barjau, J. Herranz
    Universitat Politécnica de Catalunya, Barcelona, Spain
  • J. Herranz
    Proactive Research and Development, Barcelona, Spain
  The new fast wire scanner foreseen to measure small emittance beams throughout the LHC injector chain will have a wire travelling at a speed of up to 20 m.s−1, with a requested wire position measurement accuracy of the order of a few microns. The vibration of the thin carbon wires used has been identified as one of the major error sources on the wire position accuracy. In this project the most challenging and innovative development has been the wire vibrations measurement strategy based on the piezo resistive effect of the wire itself, while the deflection of the fork supporting the wire has been measured by semiconductor strain gauges. Dynamic models of the wire and fork have been created to predict the behaviour of the fork-wire assembly. This model, validated by the measurements, has then been used for optimisation of the wire-fork assembly. The contribution will discuss the measurement setup and the model development as well as their comparison. In addition it will show that this technology can easily be implemented in current operating devices without major modifications. For the first time the piezo resistive effect is used for wire vibrations measurements during the scan.  
poster icon Poster TUPB052 [2.371 MB]  
TUPB053 A High Dynamic Range Diamond Detector Readout System for the CERN Beam Wire Scanners Program 1
  • J.L. Sirvent Blasco, B. Dehning, J. Emery
    CERN, Geneva, Switzerland
  • A. Dieguez
    UB, Barcelona, Spain
  A secondary particle shower acquisition system is under design for the upgrade of CERN's beam wire scanners. The system needs to be capable of performing bunch-by-bunch synchronous measurements with an integration time of 25 ns and to cope with signal variations of up to 6 orders of magnitude. The whole dynamic range should be covered by the acquisition system with a single configuration and should have no tuneable parameters. The secondary particles are detected using a polycrystalline diamond detector with the signal digitization performed nearby with a custom front-end system, designed to resist a total ionising radiation dose up to 1 kGy in 10 years. The digital data transmission, front-end synchronization and control are performed through a bi-directional optical link operating at 4.8 Gbps using CERN's GBT protocol. For the digitization, two radiation tolerant integrator ASICs (ICECAL and QIE10) are under study.  
poster icon Poster TUPB053 [1.319 MB]  
TUPB054 Electromagnetic Field Pre-alignment of the Compact Linear Collider (CLIC) Accelerating Structure with help of Wakefield Monitor Signals 1
  • N. Galindo Munoz, N. Catalán Lasheras, M. Wendt, S. Zorzetti
    CERN, Geneva, Switzerland
  • V.E. Boria
    DCOM-iTEAM-UPV, Valencia, Spain
  • A. Faus-Golfe
    IFIC, Valencia, Spain
  Funding: The PACMAN project is funded by the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 606839
The CLIC project, currently under study at CERN is an electron-positron collider at 3 TeV centre-of-mass energy and luminosity of 2*1034 cm-2s−1. Achieving such luminosity requires a beam dimension of 1 nm in the vertical plane and high beam stability. The TD24 is a traveling wave structure operating at 12 GHz designed to reach 100 MV/m at constant gradient. It consists of two coupling cells and 24 disks. The RF is coupled from cell to cell though an iris of 5.5 mm. To minimize the occurrence of wake-fields and minimize the emittance growth Δεy below 5%, the pre-alignment precision of the electrical centre of the accelerating structure (AS) on its support has to be better than 7 μm. Following, the AS is actively aligned with beam using the wake-field monitor (WFM) signals, with a resolution of 3.5 μm. A test bench for laboratory measurements has been designed and exploits the asymmetry created by RF scattering parameters of an off-centre conductive wire, stretched to locate the electromagnetic centre of the AS. Simulations and preliminary measurement results are presented.
poster icon Poster TUPB054 [2.700 MB]  
TUPB055 Design of a Laser-based Profile Monitor for LINAC4 Commissioning at 50 MeV and 100 MeV 1
  • T. Hofmann, E. Bravin, U. Raich, F. Roncarolo
    CERN, Geneva, Switzerland
  • G.E. Boorman, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
  Funding: Marie Curie Network LA3NET which is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191.
A laser-based profile monitor has been designed for commissioning of CERN's LINAC4 accelerator at 50 MeV and 100 MeV, as part of the development of a non-destructive profile and emittance monitor foreseen for the final 160 MeV beam. The system is based on a low power laser which is scanned through the H beam. Electrons, which are photo-detached from the ions by the laser, are deflected by a steerer magnet and measured by a diamond detector. The custom designed diamond detector is tailored to minimize the disturbance due to the electromagnetic field of the passing main beam. The laser source will be installed in the LINAC4 Klystron gallery located 75 m away from the profile station and an optical fiber will transport the laser to the tunnel. The laser propagation for different pulse length and peak power values was characterized with laboratory tests with such a long fiber. In this paper we describe the overall design, focusing on key elements such as the fiber-based laser transport and the electron detection with the diamond detector.
poster icon Poster TUPB055 [1.647 MB]  
TUPB056 Transverse Rigid Dipole and Intra-Bunch Oscillation Detection Using the Transverse Feedback Beam Position Detection Scheme in SPS and LHC 1
  • W. Höfle, G. Kotzian, D. Valuch
    CERN, Geneva, Switzerland
  The LHC and SPS transverse dampers use beam position electronics with I,Q detection at 400 MHz and 200 MHz, of the sum and difference signals from a strip-line pick-up. Digitization is performed to give synchronous bunch-by-bunch data at the rate of 40 MHz corresponding to the bunch spacing of 25 ns. A performance in the um range is achieved with beams in LHC and has contributed to the high performance of the essential transverse feedback during the LHC run 1. In the present paper we review the systems deployed and their performance as well as the potential of the I,Q detection to also detect intra-bunch motion. The principle is illustrated using data from the LHC scrubbing runs in which intra-bunch motion is expected and has been observed due to electron cloud instabilities. The potential use of this signal to drive a transverse intra-bunch feedback system is outlined.  
TUPB057 Development of a Versatile OTR-ODR Station for Future Linear Colliders. 1
  • R. Kieffer, M. Bergamaschi, 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, J.P. Shanks
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L.M. Bobb
    DLS, Oxfordshire, United Kingdom
  • N. Terunuma
    KEK, Ibaraki, Japan
  In order to study the feasibility of Optical Transition (OTR) and Diffraction (ODR) Radiation based profile measurement for the future electron-positron linear colliders (ILC, CLIC) a new dedicated instrument is under development at CERN to be installed in KEK-ATF2 beam line in fall 2015. To optimize sensitivity to micron and sub-micron beam sizes, we plan to observe ODR/OTR in the visible-UV wavelength range, down to approximately 150 nm. ODR light will be produced by narrow (25-500 μm) slits with non-uniform reflectivity. To improve our knowledge on the complex pattern produced by ODR, a preparatory experiment is being conducted on the CTF3 CALIFES beam line (CERN). This device produces interferences between two OTR screens in the visible optical range with the possibility to control the distance between them, i.e. to probe the shadowing region. The new results of this OTR interference measurement will be presented, together with the latest results from the ODR run in CesrTA (Wilson lab-Cornell).  
TUPB058 A New Orbit System for the CERN Antiproton Decelerator 1
  • R. Marco-Hernandez, M.E. Angoletta, M. Ludwig, J.C. Molendijk, F. Pedersen, R. Ruffieux, J. Sanchez-Quesada, L. Søby
    CERN, Geneva, Switzerland
  This contribution will describe the new orbit system foreseen for the Antiproton Decelerator (AD) located at CERN. The AD decelerates antiprotons from 3.57 GeV/c down to 100 MeV/c, with an intensity ranging from 1×107 to 5×107 particles. The orbit system developed is based on 34 horizontal and 29 vertical electrostatic beam position monitors (BPMs) fitted with existing low noise front-end amplifiers. After amplification, the BPM signals will be digitized and down-mixed to baseband, decimated and filtered before computation to extract the position. The digital acquisition part of the orbit measurement system is based on the VME Switched Serial (VXS) enhancement of the VME64x standard and includes VITA57 standard FPGA Mezzanine Cards (FMC). The system is foreseen to measure complete orbits every 2.5 ms with a resolution of 0.1 mm.  
poster icon Poster TUPB058 [0.952 MB]  
TUPB059 Development of an Ionization Profile Monitor Based on a Pixel Detector for the CERN Proton Synchrotron 1
  • J.W. Storey, D. Bodart, B. Dehning, S. Levasseur, P. Pacholek, A. Rakai, M. Sapinski, G. Schneider, D. Steyart
    CERN, Geneva, Switzerland
  • K. Satou
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  The transverse emittance measurement in the CERN Proton Synchrotron is currently performed using fast rotational wire scanners. These scanners cannot provide continuous bunch-by-bunch measurements and the expected future increase of the beam brightness will lead to an accelerated sublimation of the wire. A novel Ionization Profile Monitor is being constructed to cope with these challenges. The readout of this device will be based on a hybrid silicon pixel detector with a Timepix3 chip. Pixel detectors are sensitive to single electrons therefore eliminating the need for traditional Multi-Channel Plates, which suffer from ageing phenomena. The early digitization of the signal will reduce the susceptibility of the readout system to electromagnetic interference, while the time resolution of the chip allows the required bunch-by-bunch measurement. Due to the small length of the detector a new, simplified ion trap has been designed. Resistive glass plates are used to provide maximum uniformity of the electric field and to simplify construction. The guiding field will be provided by a new, self-compensating magnet. It is foreseen to have the device ready for testing with beam in 2016.  
TUPB060 Development and Test of High Resolution Cavity BPMs for the CLIC Main Beam Linac 1
  • J.R. Towler, T. Lefèvre, M. Wendt
    CERN, Geneva, Switzerland
  • S.T. Boogert, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • B.J. Fellenz
    Fermilab, Batavia, Illinois, USA
  The main beam of the Compact LInear Collider (CLIC) requires the beam trajectory to be measured with 50 nm spatial resolution. It also requires a time resolution capable of making position measurements of the head and tail of the 156 ns long CLIC bunch train, for use in dispersion free steering based on an energy chirp applied along the train. For this purpose, a stainless steel 15 GHz cavity BPM prototype has been manufactured, installed at the CLIC Test Facility (CTF3) and tested with beam. An improved design has been fabricated from copper. We discuss results from the two types of the prototype pickups, both from laboratory tests and from beam tests. We also cover the development of the new downconverter electronics.  
TUPB061 Experience From the Construction of a New Fast Wire Scanner Prototype for the CERN- SPS and its Optimisation for Installation in the CERN-PS Booster 1
  • R. Veness, W. Andreazza, N. Chritin, B. Dehning, J. Emery, D. Gudkov, J. Herranz, P. Magagnin, E. Piselli, S. Samuelsson
    CERN, Geneva, Switzerland
  A new design of wire scanner is under development for the LHC Injector Upgrade project at CERN. A prototype has been designed, built and installed in the SPS accelerator to test the concept in an operational accelerator environment. New technology has been developed and qualified for in-vacuum motor and structural components using 3D metal additive machining. This paper will describe the technology developed for this scanner and the test results to date. This prototype has recently been re-optimised to fit in the limited space available in the PS Booster rings. This design will also be presented.  
poster icon Poster TUPB061 [0.866 MB]  
TUPB062 Status of the PACMAN Project 1
  • H. Mainaud Durand, K. Artoos, M.C.L. Buzio, D. Caiazza, N. Catalán Lasheras, A. Cherif, I.P. Doytchinov, J.-F. Fuchs, A. Gaddi, N. Galindo Munoz, J. Gayde, M. Modena, P. Novotny, S. Russenschuck, C. Sanz, G. Severino, K.W. Solomon, D. Tshilumba, V. Vlachakis, M. Wendt, S. Zorzetti
    CERN, Geneva, Switzerland
  Funding: The PACMAN project is funded by the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 606839
PACMAN, a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale, is an Innovative Doctoral Program, funded by the European Commission, hosted by CERN. The objective is to propose new methods allowing the determination of the reference axis of accelerator components with respect to external alignment targets. A test bench, using real components of the Compact Linear Collider (CLIC) study, will demonstrate the feasibility of the solutions developed with micrometric accuracy. The study concerns the methods developed using a stretched wire to determine the magnetic axis of small aperture magnets, the electrical centre of a 15 GHz RF-BPM or the electro-magnetic axis of an accelerating cavity. Solutions are also carried out to measure the position of the wire with respect to the external alignment targets, using a 3D Coordinate Measuring Machine or portable alternatives based on Frequency Scanning Interferometry or micro-triangulation. Other systems developed are also taken into account: a nano-positioning system to validate the nanometric resolution of the BPM and a dedicated seismic sensor to characterize the environment during the measurements.
poster icon Poster TUPB062 [2.146 MB]  
TUPB063 Stretched-Wire Techniques and Measurements for the Alignment of a 15GHz RF-BPM for CLIC 1
  • S. Zorzetti, N. Galindo Munoz, M. Wendt
    CERN, Geneva, Switzerland
  • L. Fanucci
    Università di Pisa, Pisa, Italy
  Funding: The PACMAN project is funded by the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 606839
For the Compact LInear Collider (CLIC) project at CERN, maintaining low emittance beams, as they are transported along the two independent 10-20 km long main linacs, is crucial. The beam trajectory therefore has to be very well aligned to the magnetic centre of the quadrupole magnets. A series of microwave cavity beam position monitors (BPM) is foreseen to detect the position of the beam along the main linacs to precisely monitor the beam trajectory in the circular beam pipe of only 8 mm diameter. The PACMAN project aims to demonstrate the pre-alignment of the magnetic field of a main CLIC quadrupole with the electro-magnetic centre of a 15 GHz RF-BPM to the required sub-micron accuracy. This paper focuses on stretched-wire measurements of a CLIC Test Facility (CTF) cavity BPM, to locate its electrical centre. Details of two measurement methods are discussed: RF signal excitation of the wire and analysis of RF signal transfer through the slot-coupled waveguides of the cavity, using the stretched wire as a passive target. This contribution will present the theory behind these measurements, their electromagnetic analysis and first, preliminary experimental results.
poster icon Poster TUPB063 [7.351 MB]  
Status of The European XFEL Transverse Intra Bunch Train Feedback System  
  • B. Keil, R. Baldinger, R. Ditter, M. Gloor, W. Koprek, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler, D.M. Treyer
    PSI, Villigen PSI, Switzerland
  Funding: This work was partially funded by the Swiss State Secretariat for Education, Research and Innovation SERI
The European XFEL (E-XFEL) will have a transverse intra bunch train feedback system (IBFB) that is capable of correcting the beam position of individual bunches in the ~650us long bunch train, with a minimal bunch spacing of 222ns. The IBFB measures the beam positions with high-resolution cavity BPMs, and corrects the position of each bunch via stripline kicker magnets driven by class AB solid-state RF power amplifiers. The production of the IBFB BPM pickups is finished, and a pre-series version of the low-latency BPM electronics, including firmware and software, has been successfully tested with beam. After successful production and tests of prototypes, the series production of IBFB kicker magnets and RF power amplifiers is in progress. The IBFB feedback electronics hardware development is mainly finished, while firmware and software development is still in progress. This report summarizes the latest design status and test results of the different IBFB system components.
TUPB065 Status of The SwissFEL BPM System 1
  • B. Keil, R. Baldinger, R. Ditter, D. Engeler, W. Koprek, R. Kramert, A. Malatesta, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler
    PSI, Villigen PSI, Switzerland
  SwissFEL is a 5.8GeV free electron laser facility presently under construction at PSI. The electron beam position will be measured by three types of cavity beam position monitors. For the injector, linac and beam transfer lines, low-Q 3.3GHz cavity BPMs with 38mm and 16mm aperture (CBPM38 and CBPM16) will be used to measure the position and charge of two bunches with 28ns spacing individually. A fast kicker system distributes each bunch to a different undulator line, where 4.9GHz high-Q cavity BPMs with 8mm aperture (CBPM8) are used in the undulator intersections. The production of the CBPM38 pickups is finished, while the CBPM16 production is in progress. For CBPM8, a prototype pickup has been successfully tested, and a 2nd pre-series prototype with reduced dark-current sensitivity is currently in production. The development of the common 3.3GHz CBPM electronics for CBPM38 and CBPM16 is finished, while the CBPM8 electronics is currently in the prototyping phase. This paper gives an overview of the present pickup, electronics, firmware and software design and production status, including test results and methods to control and maintain the quality during series production.  
poster icon Poster TUPB065 [0.682 MB]  
TUPB066 Preliminary Test of the Bunch-by-Bunch Transverse Feedback System for TPS Storage Ring 1
  • Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, H.P. Hsueh, K.H. Hu, C.Y. Liao
    NSRRC, Hsinchu, Taiwan
  Commissioning of the Taiwan Photon Source (TPS) is in progress and divided into two phases. The storage ring equips with two five-cell PETRA RF cavities and without insertion devices installed for Phase-I commission to confirm correctness of everything, to do preliminary vacuum clearing, and wait available of cryogenic system available. After finished the Phase I commissioning in March, 2015, installation of two superconducting RF cavities and 10 sets of insertion devices are ongoing. The commissioning is planned to start around in August. There is a prototype vertical stripline kicker installed in 2014. One horizontal stripline kicker and two vertical stripline kickers were installed in May. Commercial available feedback processor was selected for the feedback system integration. Preliminary feedback loop closed have been tested during Phase-I beam commissioning in early 2015 with prototype vertical kicker. Beam commissioning with new kickers is scheduled when beam stored in Phase-II beam commissioning which will started soon. Final check before beam test is under way.  
TUPB067 Synchrotron Radiation Measurement at Taiwan Photon Source 1
  • C.Y. Liao, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, H.P. Hsueh, K.H. Hu, C.K. Kuan, C.Y. Wu
    NSRRC, Hsinchu, Taiwan
  The synchrotron radiation light produced from a dipole magnet is widely used to characterize beam parameters in synchrotron light source (photon synchrotron). The synchrotron radiation monitor (SRM) systems were implemented for the booster synchrotron and the storage ring at Taiwan Photon Source (TPS). The beam parameters of the booster were recorded during the energy ramping process through the CCD camera and streak camera. The beam size measurement and beam behavior observed of the storage ring were performed by X-ray pinhole camera and streak camera respectability. The results are summarized in this report.  
TUPB068 Commissioning of BPM System for the TPS Project 1
  • P.C. Chiu, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang, C.H. Kuo, D. Lee
    NSRRC, Hsinchu, Taiwan
  Beam position monitor system for TPS (Taiwan Photon Source) project include several different kinds of button BPMs distributed at transfer line and booster synchrotron booster, and the storage ring. All BPM equip with commercial Libera single-pass BPM electronics and Libera Brilliance+ BPM electronics. Commissioning of the TPS accelerator system start in late 2014 for phase I commissioning until the first quarter of 2015. Phase II commissioning equip with SRF and insertion devices is schedule in the 3rd and 4th quarter of 2015. System integration, software supports, tools available for commissioning, functionality and performance of BPM system will be summary in this reports.  
A Design Study on BPMs for TAC-TARLA IR FEL Facility  
  • M. Tural Gundogan, Ö. Yavaş
    Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey
  • A.A. Aksoy, A. Aydin, Ç. Kaya
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC) in Golbasi Campus of Ankara University. TARLA is proposed to generate oscillator mode FEL in 3-250 microns wavelengths range and Bremsstrahlung radiation. It will consist of normal conducting injector system with 250 keV beam energy and two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The electron beam will be in both Continuous wave (CW) and Macro pulse (MP) modes. The bunch charge will be limited by 77pC and the average beam current will be 1 mA. In this study, simulation studies for the design of different types TARLA BPMs (Beam Position Monitors) will be presented. Mechanical and electronic designs, antenna simulations, and the latest testing procedures are determined for Button, Stripline and Cavity type BPMs. Ansoft HFSS and CST Particle Studio simulation tools are used to compare the results. Work supported by Turkish State Planning Organization (Grant No: DPT2006K-120470)  
TUPB070 Beam Characterization Using Laser Self-Mixing 1
  • A.S. Alexandrova, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A.S. Alexandrova, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  Funding: The European Union's Seventh Framework Programme under grant agreement no 289191; HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute Core Grant No.ST/G008248/1
Non-destructive diagnostics of particle beams is highly desirable for essentially any accelerator or storage ring. This concerns the characterization of the primary beam itself, but also for example of atom and molecular jets that are crossed with the primary beam as experimental targets or for diagnostics purposes. A laser-feedback interferometer based on the optical self-mixing effect provides a low-cost, robust, compact and non-invasive sensor for velocity, displacement and density measurements of various targets. This contribution presents results from theoretical and experimental studies into the factors influencing the performance and accuracy of this sensor. Parameters that have been assessed include the target velocity, the size of scattering particles, their density, type and scattering properties.
poster icon Poster TUPB070 [3.385 MB]  
TUPB071 Simulations of the FETS Laser Diagnostic 1
  • A. Kurup, J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • S.M. Gibson, K.O. Kruchinin
    JAI, Egham, Surrey, United Kingdom
  • S.M. Gibson, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  The Front-End Test Stand (FETS) aims to demonstrate clean chopping of a 60mA, 3MeV H ion beam. Such high beam intensities require unconventional emittance and profile measuring devices such as the laserwire system that will be used on FETS. A laser is used to neutralise part of the H ion beam. The main beam is then separated from the stripped beam by using a dipole magnet. This paper presents tracking results of the laser diagnostic lattice using a simulated field map of an existing dipole magnet and investigates the possibility of laser stripping upstream of the dipole.  
High Frequency Electro-Optic Beam Position Monitors for Intra-Bunch Diagnostics at the LHC  
WEDLA02   use link to access more material from this paper's primary paper code  
  • S.M. Gibson, A. Arteche, G.E. Boorman, A. Bosco
    Royal Holloway, University of London, Surrey, United Kingdom
  • P.Y. Darmedru, T. Lefèvre, T.E. Levens
    CERN, Geneva, Switzerland
  At the HL-LHC, proton bunches will be rotated by crab-cavities close to the interaction regions to maximize the luminosity. A method to rapidly monitor the transverse position of particles within each 1ns bunch is required. A novel, compact beam diagnostic to measure the bunch rotation is under development, based on electro-optic crystals, which have sufficient time resolution (<50ps) to monitor intra-bunch perturbations. The electro-optic beam position monitor uses two pairs of crystals, mounted on opposite sides of the beam pipe, whose birefringence is modified by the electric field of passing charged particle beam. The change of birefringence depends on the electric field which itself depends on the beam position, and is measured using polarized laser beams. The electro-optic response of the crystal to the passing bunch has been simulated for HL-LHC bunch scenarios. An electro-optical test stand including a high voltage modulator has been developed to characterize LiTaO3 and LiNiO3 crystals. Tests to validate the different optical configurations will be reviewed. The opto-mechanical design of an electro-optic prototype that will be installed in the CERN SPS will be presented.  
slides icon Slides TUPB072 [46.471 MB]  
TUPB073 Characterising the Signal Processing System for Beam Position Monitors at the Front End Test Stand 1
  • G.E. Boorman, S.M. Gibson, N. Rajaeifar
    Royal Holloway, University of London, Surrey, United Kingdom
  • J.D. Gale
    University of Sussex, Brighton, United Kingdom
  • S. Jolly
    UCL, London, United Kingdom
  • S.R. Lawrie
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • A.P. Letchford
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  A number of beam position monitors are being installed at the Front End Test Stand H ion source at the Rutherford Appleton Laboratory, UK, as part of the 3 MeV medium energy beam transport. The FETS ion source delivers pulses up to 2 ms long at a rate up to 50 Hz and a maximum current of 60 mA, with a 324 MHz micro-bunch structure imposed by the frequency of the FETS RF acceleration cavity. The response of an in-house designed button BPM has been simulated and then characterised on a wire-based test-rig and the results are presented. The output from a custom algorithm running on a commercial PXI-based FPGA signal processing system is evaluated using test signals from both a function generator and the BPM in the test-rig, to verify the speed and precision of the processing algorithm. The processing system can determine the beam position in eight BPMs, with a precision of better than 20 microns, within one microsecond of the signal sampling being completed. Work is ongoing to reduce the processing time to below 300 ns.  
poster icon Poster TUPB073 [0.547 MB]  
TUPB075 Development of a Supersonic Gas Jet Beam Profile Monitor 1
  • H.D. Zhang, A. Jeff, V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Jeff
    CERN, Geneva, Switzerland
  • A. Jeff, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis
    RIKEN, Saitama, Japan
  • V. Tzoganis
    RIKEN Nishina Center, Wako, Japan
  A supersonic gas jet beam profile monitor has been developed by the QUASAR Group at the Cockcroft Institute, UK. It creates a supersonic gas curtain which interacts with the primary beam, and then images the beam cross-section by collecting the generated ions. The gas curtain is inclined at 45 degrees to the beam and functions as a minimally intercepting screen, which allows it to be used in high energy and high power beams without worrying about material damage. An accurate profile measurement requires homogeneous gas density across the curtain, while high resolution measurement requires a very thin jet. In order to characterize the gas curtain density distribution and understand the jet better, a new movable gauge module has been installed in the gas jet test stand. In this contribution, we discuss the monitor design and the characterization of the gas curtain with the newly installed movable gauge module. In addition, we present a new method for the generation of a very narrow pencil jet using deBroglie wave focusing. Such a narrow jet could be used as a non-invasive counterpart to wire scanners in high-intensity beams where the latter cannot be used.  
TUPB077 Installation Status of the Electron Beam Profiler for the Fermilab Main Injector 1
  • R.M. Thurman-Keup, M.L. Alvarez, J. Fitzgerald, C.E. Lundberg, P.S. Prieto, M. Roberts, J.R. Zagel
    Fermilab, Batavia, Illinois, USA
  • W. Blokland
    ORNL, Oak Ridge, Tennessee, USA
  The planned neutrino program at Fermilab requires large proton beam intensities in excess of 2 MW. Measuring the transverse profiles of these high intensity beams is challenging and often depends on non-invasive techniques. One such technique involves measuring the deflection of a probe beam of electrons with a trajectory perpendicular to the proton beam. A device such as this is already in use at the Spallation Neutron Source at ORNL and the installation of a similar device is underway in the Main Injector at Fermilab. The present installation status of the electron beam profiler for the Main Injector will be discussed together with some simulations and test stand results.  
poster icon Poster TUPB077 [2.490 MB]  
TUPB080 Signal Processing Algorithm for Beam Position and Phase Monitors at LANSCE 1
  • R.C. McCrady, H.A. Watkins
    LANL, Los Alamos, New Mexico, USA
  Funding: This work is supported by the United States Department of Energy under contract DE-AC52-06NA2596.
The new beam position and phase monitors at LANSCE measure the phase of the beam relative to a reference signal from the master reference oscillator. Because of the various beam pulse formats used at LANSCE the algorithm needs to be flexible and to work well with short bursts of signals. We have developed an algorithm that provides phase resolution of better than 0.25 degrees with signal bursts one microsecond long, and also allows measurement of bursts as short as 100 nanoseconds. For beam position measurements flexibility took priority over precision; the processing scheme provides precision of less than 0.1 mm. In this paper we will present the principles of the algorithm and results of measurements.
TUPB081 LANSCE 1L Harp Data Acquisition System Upgrade: First Results 1
  • J.D. Sedillo, D. Martinez, J.D. Nguyen
    LANL, Los Alamos, New Mexico, USA
  Funding: U.S. Department of Energy under contract no. DE-AC52-06NA25396
Efforts applied toward the upgrade of the LANSCE 1L harp beam diagnostic data acquisition system have completed with the system's successful deployment in late December 2014. Leveraging the principle of secondary electron emission, the data acquisition system measures the particle beam-induced, negative charge-loss response of a statically-located, harp-style, beam diagnostic sensor. The harp's sense wires span two orthogonal planes, transversely oriented with the beam's direction of travel resulting in two orthogonal profiles. The profile data provided by this beam diagnostic system allows LANSCE operators to measure the particle beam's transverse properties prior to reaching its final destination: the 1L target. Details will be provided with respect to the system's final hardware architecture, the system's theoretical beam response model, and the system's measured beam response.
Performance of the New Fast Wire Scanner at the LCLS  
  • P. Krejcik, M.L. Campell, J.M. D'Ewart, H. Loos
    SLAC, Menlo Park, California, USA
  Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515.
A new fast wire scanner based on a linear DC servo motor acting through dual bellows has been developed at SLAC. After successful beam testing at LCLS we are now replacing all the old style stepping motor driven scanners with the new type. The fast scanner design allows full emittance scans to be completed in seconds rather than minutes as before, facilitating speedier tuning of the accelerator. The low vibration design allows for wire speeds up to 1 m/s, making it also suitable for use in the new LCLS-II machine where high wire speeds are essential to prevent wire breakage from the high power electron beam with a 1 MHz repetition rate. The wire scanner design is presented along with beam measurements demonstrating its performance.
TUPB084 Cherenkov Converter for Large Dynamic Range, High Sensitivity Detectors for Use on Wire-Scanners 1
  • J. Gubeli, P.E. Evtushenko
    JLab, Newport News, Virginia, USA
  We are developing a wire-scanner with a dynamic range of 10+6 or larger. In addition to the large dynamic range (LDR), high sensitivity is very desirable so that measurements can be made with a small amount of beam or small duty cycle beam. This high sensitivity requirement makes photo multiplier tubes (PMT) the preferred detector. Low dark current PMTs have maximum quantum efficiency in the visible wavelength range. We describe a converter where Cherenkov radiation (CR) is used to generate visible photons from electrons and positrons that are present due to wire-beam interaction. Also described is an optical system that collects and couples the CR into an optical fiber that delivers the visible photons to the PMT outside of the accelerator area, reducing background. The directional nature of the CR is used in a way that, when CR in the radiating medium is generated by particles not directed from the wire-beam interaction point to the converter, the CR is not coupled into the optical fiber and therefore does not create background for the wire-scanner measurements. Sensitivities to the refractive index of the radiating medium, alignment and mechanical tolerances are also presented.
*Work supported by US DOE office of Basic Energy Sciences under the early career program; DOE award number FWP#JLAB-BES11-05
poster icon Poster TUPB084 [1.383 MB]  
TUPB085 Multi-Diagnostic Transverse Profile Monitor Chamber for Extreme Ultraviolet Lithography 1
  • T.J. Campese, R.B. Agustsson, M.A. Harrison, B.T. Jacobson, A.Y. Murokh, A.G. Ovodenko, M. Ruelas, H.L. To
    RadiaBeam, Santa Monica, California, USA
  • M.G. Fedurin, I. Pogorelsky, T.V. Shaftan
    BNL, Upton, Long Island, New York, USA
  Funding: DOE SBIR Grant No DE-SC0007703
RadiaBeam Technologies has developed a compact transverse beam profile measurement system for the Extreme Ultraviolet Lithography (EUL) experiment at the Brookhaven National Laboratory-Accelerator Test Facility (BNL-ATF). The EUL experiment requires fine e-beam and laser alignment across multiple passes. To accomplish this, the system consists of four profile monitor diagnostics: Interaction Point (IP), upstream, downstream, and a sub-micron resolution diagnostic 11.5 mm downstream of the IP. Care was taken in the design to minimize footprint, avoid possible diagnostic collisions, and maximize ease of assembly and alignment. This paper will review the requirements for the dimensional and optical constraints and solutions for this experiment.
poster icon Poster TUPB085 [0.571 MB]  
TUPB086 Observation of Ion-induced Instabilities at NSLS2 Storage Ring 1
  • W.X. Cheng, Y. Li, B. Podobedov
    BNL, Upton, Long Island, New York, USA
  NSLS2 storage ring has been commissioned and is open for user operations. At relatively low beam current (~ 25mA) multi-bunch fills, ion-induced instabilities have been observed. For the present user operations, 150mA of total beam current is filled in ~1000 bunches, fast ion is the dominant instability at the NSLS2 storage ring. Although the ion-induced dipole motions can be suppressed using bunch by bunch (BxB) feedback system and it is expected to decrease in severity as the vacuum conditioning progresses further, a thorough understanding and characterization of this effect is still important, especially in preparation to the future 500mA operations. A number of ion instability related studies, mostly parasitic to other machine activities, have been carried out at various fill patterns and beam currents. Preliminary measurement results are reported in this paper.  
Magnet Edge Radiation for Non-Destructive Emittance Measurements  
  • M.G. Fedurin, M. Babzien, O.V. Chubar, C. Swinson
    BNL, Upton, Long Island, New York, USA
  • V. Yakimenko
    SLAC, Menlo Park, California, USA
  A non-destructive emittance measurement technique is presently under development at Brookhaven National Laboratory Accelerator Test Facility (BNL ATF). The properties of magnet edge radiation produced by an electron beam may be used for this purpose. The interference pattern of radiation, produced at two magnet edges, at a certain wavelength depends on transverse beam size. Magnets configuration setup, observation diagnostics and measurement results will be discussed in this report.