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diagnostics

  
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MO203 Non-Interfering Beam Diagnostic Developments electron, ion, linac, proton 13
 
  • A. Peters, P. Forck
    GSI, Darmstadt
  New high power proton and heavy ion linac projects are a big challenge for beam diagnostic developments. Due to the high inherent beam power mostly all destructive measurement techniques are not applicable. Thus a lot of beam diagnostic developments are under way from enhancements of well-known systems like beam position pick-ups or current transformers to new designs for profile or bunch length measurements using e.g. the interaction of the high power beams with the residual gas in the linacs. The latest progress in this field will be reviewed with descriptions of some remarkable solutions.  
Transparencies
 
MOP21 The Pre-Injector Linac for the Diamond Light Source linac, gun, electron, booster 84
 
  • C. Christou, V. Kempson
    DIAMOND, Chilton, Didcot, Oxon
  • K. Dunkel, C. Piel
    ACCEL, Bergisch Gladbach
  The Diamond Light Source is a new medium-energy high brightness synchrotron light facility which is under construction on the Rutherford Appleton Laboratory site in the U.K. The accelerator facility can be divided into three major components; a 3 GeV 561 m circumference storage ring, a full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the linac design and plans for operation. The linac is supplied by ACCEL Instruments GmbH under a turn-key contract, with Diamond Light Source Ltd. providing linac beam diagnostics, control system hardware and standard vacuum components. Commissioning of the linac will take place in early 2005 and user operation of the facility will commence in 2007.  
 
MOP26 ERLP Gun Commissioning Beamline Design electron, gun, emittance, laser 93
 
  • D.J. Holder, C.K.M. Gerth, F.E. Hannon
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R.J. Smith
    CLRC, Daresbury, Warrington, Cheshire
  The 4GLS project is a novel next-generation solution for a UK national light source. It is based on an energy recovery linac (ERL) operating at high average beam currents up to 100 mA and with compression schemes producing pulses in the 10 - 100 fs range. This challenging accelerator technology, new to Europe, necessitates a significant R&D programme and a major part of this is a low-energy prototype, the ERLP, which is currently under construction at Daresbury Laboratory, in the north-west of England. The first components of ERLP to be built will be the DC photocathode gun and low-energy beam transport and diagnostics. The gun will initially be operated with a diagnostic beamline in order to measure the properties of the high-brightness beams generated as fully as possible. This will allow comparison of its performance with the results of multi-particle tracking codes, prior to its integration into the ERLP machine. The diagnostic beamline will include diagnostics for measuring the transverse and longitudinal properties of the electron beam. This paper will describe the design of this diagnostic beamline and demonstrate through simulation, the expected characteristics and performance achievable from this system.  
 
MOP69 RF Control Modelling Issues for Future Superconducting Accelerators resonance, feedback, linac, beam-loading 180
 
  • A. Hofler, J. R. Delayen
    TJNAF, Newport News, Virginia
  • V. Ayvazyan, A. Brandt, S. Simrock
    DESY, Hamburg
  • T. Czarski
    WUT, Warsaw
  • T. Matsumoto
    KEK, Ibaraki
  The development of superconducting accelerators has reached a high level of maturity following the successes of ATLAS at Argonne, CEBAF at Jefferson Lab, the TESLA Test Facility at DESY and many other operational accelerators. As a result many new accelerators under development (e.g. SNS) or proposed (e.g. RIA) will utilize this technology. Covering all aspects from cw to pulsed rf and/or beam, non-relativistic to relativistic particles, medium and high gradients, light to heavy beam loading, linacs, rings, and ERLs, the demands on the rf control system can be quite different for the various accelerators. For the rf control designer it is therefore essential to understand these issues and be able to predict rf system performance based on realistic rf control models. This paper will describe the features that should be included in such models and present an approach which will drive the development of a generic rf system model.  
 
TUP46 A New Control System for the S-DALINAC electron, alignment, target, beam-losses 372
 
  • M. Brunken, W. Ackermann, A. Araz, U. Bonnes, H.-D. Gräf, M. Hertling, A. Karnaukhov, W.F.O. Müller, O. Patalakha, M. Platz, A. Richter, B. Steiner, O. Titze, B. Truckses, T. Weiland
    TU Darmstadt, Darmstadt
  We will present recent results of the development of a new control system for the superconducting cw electron accelerator S-DALINAC. This system will be based on common industrial standards. Due to the large number of special devices existing to control the beamline, a simple and cheap communication interface is required to replace the current proprietary bus topology. The existing devices will be upgraded by a microcontroller based CAN bus interface as communication path to a control server. The servers themselves may be distributed over the location, giving required applications access to the device parameters through a TCP/IP connection. As application layer protocol for the Client Server communication a special binary protocol and a text protocol based on XML are considered.  
 
TUP61 Beam Analysis Using the IPNS Linac ESEM linac, synchrotron, quadrupole, target 405
 
  • J.C. Dooling, F. R. Brumwell, L. Donley, G.E. McMichael, V. F. Stipp
    ANL, Argonne, Illinois
  The Energy Spread and Energy Monitor (ESEM) is an on-line, non-intrusive diagnostic used to characterize the output beam from the 200 MHz, 50 MeV linac. The energy spread is determined from a 3-size, longitudinal emittance measurement and energy is derived from TOF analysis. Presently, a single particle distribution is used to yield energy and energy-spread results. Effort is on-going to allow for more realistic distributions to be included. Signals are detected on terminated 50 Ω, stripline BPMs. Each BPM is constructed with four striplines: top, bottom, left and right. Until recently, the ESEM signals were taken solely from bottom striplines in four separate BPM locations in the transport line between the linac and synchrotron. We have begun to use the top stripline data to examine, in more detail, beam position and attempt to measure beam size. The electrostatic coupling between the stripline and the beam depends on the capacitance, which in turn is inversely related to the beam-stripline separation. The electrostatic portion of fluctuations in beam motion will be nonlinear, possibly allowing one to infer beam size.  
 
TUP65 RF Tuning Schemes for J-PARC DTL and SDTL linac, simulation, klystron, injection 414
 
  • M. Ikegami
    KEK, Ibaraki
  • Y. Kondo, A. Ueno
    JAERI, Ibaraki-ken
  J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac. In high-current proton linacs, precise tuning of RF amplitude and phase is indispensable to reduce uncontrolled beam loss and beam-quality deterioration. Especially, accurate RF tuning is essential for J-PARC linac, because requirement for the momentum spread is extremely severe to enable effective injection to the succeeding RCS (Rapid Cycling Synchrotron). In this paper, planned tuning schemes for the DTL and SDTL are presented together with the beam diagnostic layout for the tuning.  
 
TUP68 The LANSCE Low Momentum Beam Monitor monitoring, electron 423
 
  • R. Merl
    LANL, Los Alamos, New Mexico
  • F. R. Gallegos, C. Pillai, S. Schaller, F. E. Shelley, A. I. Steck
    LANL/LANSCE, Los Alamos, New Mexico
  • B. J. Sanchez
    ORNL/SNS, Oak Ridge, Tennessee
  A diagnostic has been developed at the Los Alamos Neutron Science Center (LANSCE) for the purpose of identifying low momentum beam tails in the linear accelerator. These tails must be eliminated in order to maintain the transverse and longitudinal beam size. Instead of the currently used phosphor camera system, this instrument consists of a Multi Wire Proportional Chamber (MWPC) front end coupled to an EPICS compliant VME-based electronics package. Low momentum tails are detected with a resolution of 5 mm in the MWPC at a high dispersion point near a bending magnet. While phosphor is typically not sensitive in the nano amp range, the MWPC is sensitive down to about a pico amp. The electronics package processes the signals from each of the MWPC wires to generate an array of beam currents at each of the lower energies. The electronics has an analog front end with a high-speed analog to digital converter for each wire. Data from multiple wires are processed with an embedded digital signal processor and results placed in a set of VME registers. An EPICS application assembles the data from these VME registers into a display of beam current vs. beam energy (momentum) in the LANSCE control room.  
 
TUP74 The Beam Diagnostics System in the J-PARC LINAC linac, beam-losses, quadrupole, radiation 441
 
  • S. Lee, Z. Igarashi, T. Toyama
    KEK, Ibaraki
  • H. Akikawa
    JAERI/LINAC, Ibaraki-ken
  • F. Hiroki, J. Kishiro, S. Sato, M. Tanaka, T. Tomisawa
    JAERI, Ibaraki-ken
  • H. Yoshikawa
    JAERI/FEL, Ibaraki-ken
  Large amount of beam monitors will be installed in J-PARC linac. Electrostatic computations are used to adjust the BPM cross-section parameters to obtain 50 Ω transmission lines. BPMs are designed to control the offset between quadrupole magnet and BPM electrical centers less than 0.1mm. We present a procedure of beam based calibration/alignment (BBC/BBA) method to confirm the displacement of linac BPMs. The fast current transformer (FCT) has response of relative bunch phase <1%. To measure the beam energy at every accelerator tank and injection point of 3 GeV RCS, phase difference of FCT pairs are used, and 10-4 order energy resolutions can be expected. The loss monitor system (BLM) is composed of scintillator and Ar-CH4/CO2 gas filled proportional counter. To prevent the activation and heat load by intense beam loss, fast time response of loss signals is required. Profile measurements can also be used to determine the beam emittance of a matched beam in a periodic focusing lattice. The thin sensing wire scanner (WS) has been designed to obtain a current density distribution of the beam. This paper describes the instruments and R&D result of beam monitors in J-PARC linac.  
 
TUP78 Diagnostics for the Low Level RF Control for the European XFEL monitoring, feedback, laser, radiation 453
 
  • T. Jezynski, P. Pucyk
    WUT, Warsaw
  • S. Simrock
    DESY, Hamburg
  One of the most important aims of the diagnostic system is to provide high reliability. This article describes the concept and the proposal for diagnostic system for Low Level Radio Frequency system for EU-XFEL. It enables immediate location of faults and understanding of their causes, tests the functionality of LLRF system, tests each the electronic board and connections. Diagnostic system tests different system components and compares results from these tests with e.g. from power supplies monitors. Hardware, software and database aspect of diagnostic system is presented. The main part of this paper is devoted to hardware and software specification.  
 
WE103 State of the Art in RF Control feedback, linac, resonance, laser 523
 
  • S. Simrock
    DESY, Hamburg
  Nowadays the designer of a new rf control system has access to a wealth of powerful digital, analog, and rf circuitry. The requirements for the rf control system have changed from only controlling the amplitude and phase of the accelerating field to the required degree to stability. Additional tasks include exception handling and extensive build-in diagnostics while pursuing issues related to reliability, operability, and maintainability. Also operation close to the performance limit must be supported while maximizing the availability of the accelerator. With many accelerator projects in planning or under construction several state-of-the art rf control designs have evolved. This paper will present an overview of this new technology and discuss its performance.  
Transparencies
 
THP49 The RF-Station Interlock for the European X-ray laser klystron, power-supply, monitoring, laser 718
 
  • T. Grevsmühl, S. Choroba, Ph. Duval, O. Hensler, J. Kahl, F.-R. Kaiser, A. Kretzschmann, K. Rehlich, U. Schwendicke, S. Simrock, S. Weisse
    DESY, Hamburg
  • H. Leich, RW. Wenndorff
    DESY Zeuthen, Zeuthen
  The RF-station interlock for the European X-ray laser will be based on a 19"- 3U crate incorporating a controller with the 32-bit RISC NIOS-processor (ALTERA). The main task of the interlock system is to prevent any damage from the components of the RF station and connected cavities. The interlock system must also guarantee a maximum time of operation of the RF stations which implies the implementation of self diagnostics and repair strategies on a module basis. Additional tasks are: collection and temporary storage of status information of the individual channels of the interlock system, transfer of this information to the control system, slow control functions (e.g. HV setting and monitoring) and control of inputs and outputs from and to other subsystems. In this paper we present the implementation using an ALTERA-FPGA running a 32-bit RISC NIOS-processor. Connection to the accelerator main control is provided by Ethernet using BSD-style socket routines based on ALTERA's plugs-library. The layout of the system is presented and first hardware components are shown.  
 
THP60 High-Power RF Distribution System for the 8-Pack Project linear-collider, collider, vacuum, resonance 751
 
  • C.D. Nantista
    SLAC/ARDB, Menlo Park, California
  • D.P. Atkinson
    LLNL, Livermore
  • J.Q. Chan
    SLAC/NLC, Menlo Park, California
  • S.Y. Kazakov
    KEK, Ibaraki
  • D.C. Schultz
    SLAC, Menlo Park, California
  • S.G. Tantawi
    SLAC/ARDA, Menlo Park, California
  The 8-Pack Project at SLAC is a prototype rf system whose goal is to demonstrate the high-power X-band technology developed in the NLC/GLC program. In its first phase, it has reliably produced a 400 ns rf pulse of over 500 MW using a solid-state modulator, four 11.424 GHz klystrons and a dual-moded SLED-II pulse compressor [1]. In Phase 2, the output power of our system has been delivered into the bunker of the NLCTA (Next Linear Collider Test Accelerator) and divided between several accelerating structures, first four and finally eight, for beam acceleration. We describe here the design, cold-test measurements, and processing of this power distribution system. Due to the high power levels and the need for efficiency, overmoded waveguide and components are used. For power transport, the TE 01 mode is used in 7.44 cm and 4.064 cm diameter circular waveguide. Only near the structures is standard WR90 rectangular waveguide employed. Components used to manipulate the rf power include transitional tapers, mode converters, overmoded bends, fractional directional couplers, and hybrids.

[1] S. Tantawi, et al., “Status of High-Power Tests of the Dual-Mode SLED-II System for an X-Band Linear Collider,” FR202, these proceedings.