• C. Gabor, H. Klein, O. Meusel, U. Ratzinger
  IAP, Frankfurt-am-Main
• J. Pozimski
  Imperial College of Science and Technology, Department of Physics, London

• M. Re, G.A.P. Cirrone, L. Cosentino, G. Cuttone, P. Finocchiaro, P.A. Lojacono
  INFN/LNS, Catania
• A. Hermanne, H. Thienpont, J. Van Erps, M. Vervaeke, B. Volckaerts, P. Vynck
  VUB, Brussels
• Y.J. Ma
  CIAE, Beijing

• T. Toyama, D.A. Arakawa, Y. Hashimoto, S. Lee, T. Miura, S. Muto
  KEK, Ibaraki
• N. Hayashi, J. Kishiro, R. Toyokawa
  JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

• S.-H. Han, Y.-S. Cho
  KAERI, Daejon

We have developed a gas scattering energy monitor to measure the energy spectrum of the proton beam at the end of 3MeV RFQ and 20MeV DTL for the low energy part of the PEFP(Proton Engineering Frontier Project). The energy monitor is comprised of a Xe scattering chamber, two collimators to reduce the beam intensity, and a surface barrier detector for measuring the proton energy. In order to measure the beam current simultaneously, a faraday cup is incorporated into the energy monitor. The calculated flux attenuation through the 0.2 mm diameter collimator is 3·10^-4 and the energy loss is 28 keV. We report on design details and multiple gas scattering of proton beams in Xe gas by using a SRIM code.

• J.H. Park, J.Y. Huang, W.H. Hwang, Y.W. Parc, S.J. Park
  PAL, Pohang, Kyungbuk
• Y.-S. Cho, B.H. Choi, S.-H. Han
  KAERI, Daejon

A proton linear accelerator is currently the construction at the KAERI (Korea Atomic Research Institute) to the PEFP (Proton Engineering Frontier Project) in Korea. We are accomplished the technique development of beam diagnostic system to be currently the construction. We treat beam diagnostics for the high power proton linear accelerator. Prototype beam position & phase monitor (BPPM) electronics was made and tested successfully in one of the beam diagnostic systems. The beam position monitor pickup electrode is a capacitive type (electrostatic type) which has a button form. Button form electrode, in common use around electron synchrotrons and storage rings, are a variant of the electrode with small button form (e.g., sub mm diameter). However, we are designed button form electrode to measure beam position of proton beam. The BCM (Beam Current Monitor) is developed Tuned CT (Current Transformer) for collaborate with Bergoz Instruments. This paper describes the status of beam diagnostic systems for the PEFP.

• I.H. Yu, D.T. Kim, S.-C. Kim, I.-S. Park, S.J. Park
  PAL, Pohang, Kyungbuk
• Y.-S. Cho
  KAERI, Daejon

The PEFP (Proton Engineering Frontier Project) at the KAERI (Korea Atomic Energy Research Institute) is building a high-power proton linear accelerator aiming to generate 100-MeV proton beams with 20-mA peak current (pulse width and max. repetition rate of 1 ms and 120 Hz respectively). We are developing a prototype digital BPPM (Beam Position and Phase Monitor) for the PEFP linac utilizing the digital technology with field programmable gate array (FPGA). The RF input signals are down converted to 10 MHz and sampled at 40 MHz with 14-bit ADC to produce I and Q data streams. The system is designed to provide a position and phase resolution of 0.1% and 0.1? RMS respectively. The fast digital processing is networked to the EPICS-based control system with an embedded processor (Blackfin). In this paper, the detailed description of the prototype digital beam position and phase monitor will be described with the performance test results.

• B. Ashmanskas, S. U. Hansen, T. Kiper, D.W. Peterson
  Fermilab, Batavia, Illinois

• G.I. Cancelo, E. James, S.A. Wolbers
  Fermilab, Batavia, Illinois

The Beam Position Monitor (BPM) readout system at Fermilab’s Tevatron has been updated and is currently being commissioned. The new BPMs use new analog and digital hardware to achieve better beam position measurement resolution. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. The signals provided by the two ends of the BPM pickups processed by analog band-pass filters and sampled by 14-bit ADCs at 74.3MHz. A crucial part of this work has been the design of digital filters that process the signal. This paper describes the digital processing and estimation techniques used to optimize the beam position measurement. The BPM electronics must operate in narrow-band and wide-band modes to enable measurements of closed-orbit and turn-by-turn positions. The filtering and timing conditions of the signals are tuned accordingly for the operational modes. The analysis and the optimized result for each mode is presented.

• J. Ning, C.-Y. Tan
  Fermilab, Batavia, Illinois

We build an electronical instrument to get the frequency response close to the pattern of transverse beam frequency response. The method is to apply 1)a time delay circuit with ADC, FIFO RAM and DAC; 2)a phase shift circuit which is an all pass filter with adjustable phase shift in the frequency range of 25kHz to 30kHz; in a feedback loop of 3)a commutating filter which is a high Q band pass filter. We can dynamically adjust the center frequency, the side band distance during the testing. With this instrument, some beam instruments can be tested without using the real beam.

• S. Pordes, J.L. Crisp, B.J. Fellenz, R.H. Flora, A. Para, A.V. Tollestrup
  Fermilab, Batavia, Illinois

The time profiles of the bunches in the Tevatron are obtained by sampling the output of a resistive wall current monitor with a 5GS/s, 2GHz bandwidth, Lecroy 6200 oscilloscope. The techniques for removing the effect of cable dispersion and for extending the dynamic range of the data by splitting the signal and using two input channels at different gains are described. The algorithms for taking these data in the time domain and deriving the momentum spread and longitudinal emittance are also given.

• J.-P. Carneiro, S. U. Hansen, A. Ibrahim, V.D. Shiltsev, J. Steimel, R.C. Webber
  Fermilab, Batavia, Illinois

• R.C. Webber
  Fermilab, Batavia, Illinois

Independent position measurement of the counter-circulating proton and antiproton beams in the Tevatron presents a challenge to upgrading the Tevatron Beam Position Monitor (BPM) system. The inherent directionality of the Tevatron BPM pickup design provides 26dB isolation between signals from the two beams. At the present typical 10:1 proton-to-antiproton bunch intensity ratio, this isolation alone is insufficient to support millimeter accuracy antiproton beam position measurements due to interfering proton signals. An accurate and manageable solution to the interfering signal problem is required for antiproton measurements now and, as machine improvements lead to increased antiproton intensity, will facilitate future elimination of antiproton bias on proton beam position measurements. This paper discusses the possibilities and complications of using time separation of the two beam signals at the numerous Tevatron BPM locations and given the dynamic longitudinal conditions of Tevatron operation. Results of measurements results using one such method are presented.

• R.K. Kutschke, J. Steimel, R.C. Webber, S.A. Wolbers
  Fermilab, Batavia, Illinois

• R. Merl, T. Spickermann
  LANL, Los Alamos, New Mexico

Custom instrumentation has been developed at the Los Alamos Neutron Science Center to measure the Proton Storage Ring (PSR) beam energy. The PSR accumulates up to 4x10¹³ protons from the linear accelerator for delivery to a spallation neutron source. The energy of the beam injected into the PSR must be adjusted so that the revolution frequency matches the ring buncher frequency, otherwise a large momentum spread will cause increased losses in high-dispersion areas. Errors in injected beam energy appear as deviations from the ideal revolution frequency. A low-cost, custom, reconfigurable VME module has been adapted to calculate the PSR revolution frequency in real-time. The module connects directly to an analog wall current monitor output and uses analog signal conditioning electronics, an analog to digital converter, field programmable gate arrays, and an embedded floating-point digital signal processor to calculate the revolution frequency. This is an improvement over the previously used method of manually measuring the frequency with an oscilloscope. Accelerator physicists can now simply observe the PSR frequency, which is dependent on beam energy, on a control room display.

LA-UR-04-8661.

• F.M. Bieniosek, S. Eylon, P.K. Roy, S. Yu
  LBNL, Berkeley, California

We have been using alumina scintillators for imaging beams in heavy-ion beam fusion experiments in 2 to 4 transverse dimensions.* The scintillator has limitations on lifetime, linearity, and time response. As a possible replacement for the scintillator, we are studying the technique of imaging the beam on a gas cloud. A gas cloud for imaging the beam may be created on a solid hole plate placed in the path of the beam, or by a localized gas puff. It is possible to image the beam using certain fast-quenching optical spectral lines that closely follow beam current density and are independent of gas density. We describe this technique and show experimental data using a nitrogen line at 394.1 nm. This approach has promise to be a new fast beam current diagnostic on a nanosecond time scale.

*FM Bieniosek, L Prost, W Ghiorso, Beam imaging diagnostics for heavy ion beam fusion experiments, Paper WPPB050, PAC 2003.

• C. Montag, L. Ahrens, P. Thieberger
  BNL, Upton, Long Island, New York

During beam acceleration at the Brookhaven accelerator complex, heavy ions are stripped off their electrons in several steps. Depending on the properties of the stripping foils, this process results in an increased energy spread and therefore longitudinal emittance growth. A tomographic phase space reconstruction technique has been applied to quantify the associated emittance growth for different stripping foil materials.

• T. Satogata, R. Calaga, P. Cameron, P. Cerniglia, J. Cupolo, A.J. Curcio, W.C. Dawson, C. Degen, J. Gullotta, J. Mead, R.J. Michnoff, T. Russo, R. Sikora
  BNL, Upton, Long Island, New York

The RHIC beam position monitor (BPM) system provides independent average orbit and turn-by-turn (TBT) position measurements. In each ring, there are 162 measurement locations per plane (horizontal and vertical) for a total of 648 BPM planes in the RHIC machine. During 2003 and 2004 shutdowns, BPM processing electronics were moved from the RHIC tunnel to controls alcoves to reduce radiation impact, and the analog signal paths of several dozen modules were modified to eliminate gain-switching relays and improve signal stability. This paper presents results of improved system performance, including stability for interaction region and sextupole beam-based alignment efforts. We also summarize performance of improved million-turn TBT acquisition channels for nonlinear dynamics and echo studies.

• M. Hu, R. H. Carcagno, J. Krider, E. Lorman, A. Marchionni, Y.M.P. Pischalnikov, S. Pordes, D. Slimmer, J. Wilson, J.R. Zagel
  Fermilab, Batavia, Illinois

• A. Jansson, M. Bowden, K. Bowie, A. Bross, R. Dysert, T. Fitzpatrick, R. Kwarciany, C. Lundberg, H. Nguyen, C.H. Rivetta, D. Slimmer, L. Valerio, J.R. Zagel
  Fermilab, Batavia, Illinois

Primarily to study emittance blowup during injection and ramping, an ionization profile monitor has been developed for the Tevatron. It is based on a prototype installed in the Main Injector, although with extensive modifications. In particular, the electromagnetic shielding has been improved, the signal path has been cleaned up, and provisions have been made for an internal electron source. Due to the good Tevatron vacuum, a local pressure bump is introduced to increase the primary signal, which is then amplified by a microchannel plate and detected on anode strips. For the DAQ, a custom ASIC developed for the CMS experiment is used. It is a combined charge integrator and digitizer, with a sensitivity of a few fC, and a time-resolution that allows single bunch measurement. Digitization is done in the tunnel to reduce noise. Preparations for detector installation were made during the long 2004 shutdown, with the installation of magnets, vacuum chambers, vacuum pumps and cabling. The actual detector will be installed sometime during the spring fo 2005. This paper describes the design of the detector and associated electronics and presents various bench test results.

• A. Jansson, P. Lebrun, J.T. Volk
  Fermilab, Batavia, Illinois

Early in Run2, there was an effort to compare the different emittance measurements in the Tevatron (flying wires and synchtotron light) and understand the origin of the observed differences. To measure the beta function at a few key locations near the instruments, air-core quadrupoles were installed. By modulating the gradient of these magents and measuring the effect on the tune, the lattice parameters can be extracted. Initially, the results seem to disagree with with other methods. At the time, the lattice was strongly coupled due to a skew component in the main dipoles, caused by sagging of the cryostat. After a large fraction of the superconducting magnets were shimmed to remove a strong skew quadrupole component, the results now agree with expectations, confirming that the beta function is not the major error source of discrepancy in the emittance measurement.

• V.E. Scarpine, C.W. Lindenmeyer, G. R. Tassotto
  Fermilab, Batavia, Illinois
• A.H. Lumpkin
  ANL, Argonne, Illinois

Optical transition radiation (OTR) detectors are being developed at Fermi National Acceleratory Laboratory (FNAL) as part of the collider Run II upgrade program and as part of the NuMI primary beamline. These detectors are designed to measure 150 GeV antiprotons as well as 120 GeV proton beams over a large range of intensities. Design and development of an OTR detector capable of measuring beam in both directions down to beam intensities of ~5·10⁹ particles for nominal beam sizes is presented. Applications of these OTR detectors as an on-line emittance monitor for both antiproton transfers and reverse-injected protons, as a Tevatron injection profile monitor, and as a high-intensity beam profile monitor for NuMI are discussed. In addition, different types of OTR foils are being evaluated for operation over the intensity range of ~5·10⁹ to over 1·10¹³ particles per pulse and these are described.

• R. Thurman-Keup, E. Lorman, T. Meyer, S. Pordes
  Fermilab, Batavia, Illinois
• S. De Santis
  LBNL, Berkeley, California

The beam bunches in the Tevatron are arranged to provide gaps in time for the abort kickers to ramp to full field. The presence of even a small fraction (few 10-4)of the beam in the abort gaps can induce quenches of the superconducting magnets and inflict severe radiation damage on the silicon detectors of the experiments. Techniques for calibrating and measuring the intensity of the beam in the abort gap using synchrotron light and a gated photomultiplier tube are described. Measurements of the evolution and longitudinal profile of the beam in the abort gap are presented.

• R.J. Macek, A. A. Browman
  TechSource, Santa Fe, New Mexico

Simulations have indicated that electron clouds generated by beam-induced multipactor can be trapped in the mirror-like fields of magnetic quadrupoles and thereby contribute significantly to the electron cloud buildup in high intensity accelerators and storage rings. This could be the most important source of electrons driving the two-stream (e-p) instability at the Los Alamos PSR and may also play a significant role in electron cloud effects at some of the new high intensity accelerator projects. We will describe the physics design and optimization of an electron-sweeping detector designed to measure the trapped electrons at various times after the beam pulse has passed. The instrument can also serve as an electro-magnetically shielded detector providing a signal obtained from electrons striking the wall during the passage of beam bunches.

• A.V. Aleksandrov, S. Assadi, S.M. Cousineau, V.V. Danilov, S. Henderson, M.A. Plum
  ORNL, Oak Ridge, Tennessee
• P.V. Logatchev, A.A. Starostenko
  BINP SB RAS, Novosibirsk

The design goal for the SNS ring is to accumulate 2·10¹⁴ protons per 1ms pulse at a 60Hz repetition rate. Achieving the design beam intensity with acceptable losses is a challenging task, which could be tackled more easily if reliable measurements of the beam profile in the ring are available. The high power density of the beam precludes the use of conventional wire scanners or harps and therefore non-interceptive types of profiles measurements are required. The electron beam probe method was suggested for measuring profiles in high power beams. In this method, deflection of a low energy electron beam by the collective field of the high intensity beam is measured. The charge density in the high intensity beam can be restored under certain conditions or estimated by various mathematical techniques. We studied the feasibility of using the electron beam probe for the SNS accumulator ring using computer simulations of the diagnostic setup. A realistic electron gun model and realistic proton beam distributions were used in the simulations. Several profile calculation techniques were explored and the results are reported in this paper.

• C. Deibele
  ORNL, Oak Ridge, Tennessee
• S.S. Kurennoy
  LANL, Los Alamos, New Mexico

The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The 805-MHz coupled-cavity linac (CCL) accelerates an H^- beam from 86 to 186 MeV, while the 805 MHz superconducting-cavity linac (SCL) accelerates the beam to its final energy of 1 GeV. The SNS beam position monitors (BPMs) which are used to measure both position and phase of the beam relative to the master oscillator, have the dual-planed design with four one-end-shorted stripline electrodes. We argue that the BPMs are optimally broadband matched to the cabling and electronics when the geometrical mean of the sum-mode and quadrupole-mode impedances is equal to the external-line impedance, 50 Ohms. The analytical results, MAFIA and HFSS simulations, wire measurements, and beam measurements that support this statement are presented.

• M.P. Stockli, R.F. Welton
  ORNL, Oak Ridge, Tennessee

Ion beam emittances are normally measured as two-dimensional distributions of the beam current fraction within a window dx centered at position coordinate x and a window dx’ centered at trajectory angle x’. Unthresholded rms emittances evaluated from experimental data are very sensitive to noise, bias, and other undesired signals. Undesired signals occur when particles from outside the measured window dx*dx’ contribute to the signal from the particles within the measured window. Increasing the window size increases the desired signal while most undesired contributions remain unchanged. However, the decreasing resolution causes an error in the emittance results, especially in the rms emittance. Using theoretical distributions we will present the tradeoff between resolution and accuracy.

• S. Sato, H. Akikawa, T. Tomisawa, A. Ueno
  JAERI/LINAC, Ibaraki-ken
• Z. Igarashi, M. Ikegami, N. Kamikubota, S. Lee, T. Toyama
  KEK, Ibaraki

• S.E. Kopp, D. Indurthy, Z. Pavlovich, M. Proga, R.M. Zwaska
  The University of Texas at Austin, Austin, Texas
• B.B. Baller, S.C. Childress, R. Ford, D. Harris, C.L.K. Kendziora, C.D. Moore, G. R. Tassotto
  Fermilab, Batavia, Illinois

• B. A. Aminov, M. G. Getta, S. K. Kolesov, N. Pupeter
  CRE, Wuppertal
• A. Geisler, T. Stephani, J. H. Timmer
  ACCEL, Bergisch Gladbach

• E.D. Gazazyan, K.A. Ispirian, A.T. Margaryan
  YerPhI, Yerevan
• D.K. Kalantaryan
  YSU, Yerevan
• E.M. Laziev
  CANDLE, Yerevan

• S.R. Marques, O.R. Bagnato, Bombacini, F.O. Bombacini, M.J. Ferreira, H. J. Onisto
  LNLS, Campinas

• S. Casalbuoni, H. Schlarb, B. Schmidt, B. Steffen
  DESY, Hamburg
• P. Schmüser, A. Winter
  Uni HH, Hamburg

• B. Steffen, S. Casalbuoni, E.-A. Knabbe, H. Schlarb, B. Schmidt
  DESY, Hamburg
• P. Schmüser, A. Winter
  Uni HH, Hamburg

• J.W. Flanagan, H. Fukuma, S. Hiramatsu, T. Mitsuhashi
  KEK, Ibaraki

• H. Ikeda, J.W. Flanagan, H. Fukuma, Y. Funakoshi, S. Hiramatsu, T. Mitsuhashi, K. Ohmi, S. Uehara
  KEK, Ibaraki

• M. Tejima, A. Arinaga, H. Fukuma, S. Hiramatsu, T. Ieiri, I. Ishii, M. Tobiyama
  KEK, Ibaraki

• S.-C. Kim, M.-H. Chun, Y.J. Han, J.Y. Huang, D.T. Kim, W.W. Lee
  PAL, Pohang, Kyungbuk

Electron Linac at the Pohnag Accelerator Laboratory (PAL) has been operated continuously as the full energy injector for storage ring. Linac and storage ring energy has been 2.0 GeV since Dec. 1994, and 2.5 GeV since Oct. 2002. In Aug. 2004, thirteen BPMs are newly installed at BTL(Beam Transport Line) for beam trajectory measurement and feedback. These BPMs consist of 100mm strip-line electrodes in 150mm long chamber, and 500MHz log-ratio signal processing circuits. BPM data acquisition system is developed as EPICS IOC using NI S-series data acquisition board and NI LabView 7.1. BTL BPMs will be used for optic correction and beam energy feedback for PLS beam injection. This paper describes on design, test results, installation and data acquisition system of the PLS BTL BPM.

• C.H. Kuo, K.-T. Hsu, M.-H. Wang
  NSRRC, Hsinchu

• T.C. Tseng, J.-R. Chen, H.C. Ho, C.-K. Kuan, C.J. Lin, S.Y. Perng, D.-J. Wang, J. Wang
  NSRRC, Hsinchu

• R.J. Smith, M. Dufau, B.G. Martlew
  CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
• G. Cox
  CCLRC/DL, Daresbury, Warrington, Cheshire

The installation of a new APPLE/II undulator with user controlled polarisation has necessitated the upgrade of the Electron Beam Position Monitoring (EBPM) detector electronics and position feedback systems. The upgraded installation will utilise commercially available multiplexed detection electronics, coupled with a two phase control system interface replacement. Phase one involves the replacement of the existing G-64 based read-back system with direct analogue connections to the VME beam steering and Feedback system. This allows existing monitoring and feedback software to work with improved update rates (~ 1Hz -> ~ 8Hz). Phase two will see the installation of new high-performance control system front ends and will allow real-time monitoring at up to 100Hz and provide snapshots with resolution of 1-10 KHz.

• M.A. Palmer, D. L. Rubin, J.C. Smith
  Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
• M. Cravey, J. Napalitano
  RPI, Troy, New York
• V. Crede
  Cornell University, Department of Physics, Ithaca, New York
• K.L. Dooley
  Vassar, Poughkeepsie, New York
• H. Vogel
  CMU, Pittsburgh, Pennsylvania

The CLEO-c experiment at the Cornell Electron Storage Ring (CESR) is presently embarking on a multi-year exploration of charm and QCD physics in the 3-5 GeV center-of-mass energy range. In order to facilitate rapid optimization of machine parameters over this energy range, a luminosity monitor based on the measurement of radiative-bhabha photons coming from the CLEO-c interaction point (IP) has been designed and installed in the CESR ring. Key design criteria of the device include: better than 1% statistical measurements of the luminosity with a 1 Hz update rate over the full range of CESR-c operating conditions; bunch-by-bunch measurement capability; a large horizontal aperture to enable measurements under conditions ranging from single-bunch head-on collisions to multi-bunch collisions with a horizontal crossing angle of up to 4~mrad; and, a segmented readout to provide direct information on beam characteristics at the IP. We review the design and performance of this device and discuss its application to machine tuning and performance studies.

• M.A. Palmer, J. Dobbins, C.R. Strohman, E. Tanke
  CESR-LEPP, Ithaca, New York

A key factor in the colliding beam performance of the Cornell Electron Storage Ring (CESR) is the impact of parasitic beam-beam interactions between bunches in the two beams as they follow their electrostatically separated orbits in a single vacuum chamber. In order to better investigate the differential performance of bunches in CESR, instrumentation electronics has been developed to allow acquisition of turn-by-turn data from multiple bunches simultaneously. The electronics consists of a standardized digital board centered around an Analog Devices TigerSHARC family digital signal processor, a communications interface, and an interface to the CESR Precision Timing System. Mated to these components is an analog front end and digitizer board which is customized for the particular diagnostic device of interest. Front ends have been developed for beam position monitor, luminosity monitor, and beam profile monitor applications. We describe the design and characterization of this new hardware.

• S. Seletsky
  Rochester University, Rochester, New York
• A.V. Shemyakin
  Fermilab, Batavia, Illinois

• J.L. Bailey, T.W. Buffington, B.X. Yang
  ANL, Argonne, Illinois

The Linac Coherent Light Source (LCLS), currently under design, requires beam diagnostic instruments between the magnets in the beam undulator section. Ten wire scanners are planned as one of the primary instruments to characterize electron beam properties. The development of these wire scanners presents several design challenges due to the need for high accuracy and resolution of the wire motion (3 microns tolerance, typical) and the high intensity of the beam (3400 A over an area of 30 micron rms radius). In this paper, we present the technical specification and design criteria for the scanners. We will also present the mechanical design of the UHV-compatible drive and its engineering analysis. Lastly, we present the wire card design and discuss associated thermal and mechanical issues originating from the highly intense x-ray and electron beams.

• T. Watanabe, M. Babzien, K. Kusche, V. Yakimenko
  BNL, Upton, Long Island, New York

• I.P. Pinayev, S.L. Kramer, J. Rose, T.V. Shaftan
  BNL, Upton, Long Island, New York

The National Synchrotron Light Source is performing R&D of a new 3 GeV electron storage ring to be used for the facility upgrade. To satisfy the demands for the brightness and stability of the future light source a state-of-the-art diagnostics system is a necessity. We present our preliminary design with focus on the requirements for instrumentation and technical solutions to achieve them.

• T.K. Kroc, T.B. Bolshakov, A.V. Burov, A.V. Shemyakin
  Fermilab, Batavia, Illinois
• S. Seletsky
  Rochester University, Rochester, New York

The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide effective cooling of the antiprotons in the Recycler. A measurement system was developed using movable appertures and steering bumps to measure the beam size in a 20 m long, nearly continuous, solenoid. This paper discusses the required beam parameters, the implimentation of the measurement system and results for our application.

• M.E. Bevins, A.R. Day, P. Degtiarenko, L.A. Dillon-Townes, A. Freyberger, R. Gilman, A. Saha, S. Slachtouski
  Jefferson Lab, Newport News, Virginia

A calorimeter has been proposed to provide 0.5% - 1.0% absolute measurements of beam current in the Hall A end station of the Thomas Jefferson National Accelerator Facility (JLab) CEBAF machine. Silver and copper calorimeters built in the 1960’s achieved precisions of about 1%. Modern powder metallurgy processes have produced high density, high thermal conductivity tungsten-copper composite materials that will minimize beam loss while maintaining a rapid thermal response time. Heat leaks will be minimized by mounting the mass in vacuum on glass ceramic mounts. A conduction cooling scheme utilizes an advanced carbon fiber compliant thermal interface material. Transient finite difference and finite element models were developed to estimate heat leaks and thermal response times.

• S.R. Kauffman, H. Dong, A. Freyberger, L. Kaufman, J. Musson
  Jefferson Lab, Newport News, Virginia

The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high-precision (1 mm), high-bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM-010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The Multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a digital receiver daughter board and digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 4 MHz, and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with a resolution of one mm, 100 kHz output bandwidth, and overall latency of ten microseconds. The results are available in both analog and digital format.

• M.A. Epps, R. Kazimi
  Jefferson Lab, Newport News, Virginia
• P.L. Gueye
  Hampton University, Hampton, Virginia

• J.M. Weber, M.J. Chin, L.R. Doolittle
  LBNL, Berkeley, California
• R. Akre
  SLAC, Menlo Park, California

The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx® ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.

• R.B. Wilcox, J.W.  Staples
  LBNL, Berkeley, California
• R. Holzwarth
  Menlo Systems GmbH, Martinsried

In femtosecond pump/probe experiments using short x-ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error. For the sub-100fs range we use an amplitude modulated CW laser at 1GHz to transmit RF phase information, and control the delay through a 100m fiber by observing the retroreflected signal. Initial results show 40fs peak-to-peak error above 10Hz, and 200fs long term drift, mainly due to amplitude sensitivity in the analog mixers. For the sub-10fs range we will lock two single-frequency lasers separated by several teraHertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes. For attosecond synchronization we propose a stabilized, free space link using bulk lens waveguides and high peak power ultrashort pulses.

• S.E. Korbly, A.S. Kesar, R.A. Marsh, R.J. Temkin
  MIT/PSFC, Cambridge, Massachusetts

Measurements of Coherent Smith-Purcell Radiation (SPR) were performed at the 17 GHz high-gradient accelerator built by Haimson Research Corporation at the MIT Plasma Science and Fusion Center. SPR is a promising radiation source because the radiation intensity is enhanced by the number of grating periods. The radiation produced obeys the SP resonance condition correlating the radiation frequency at each observation angle, allowing SPR to be exploited as a bunch-length measurement. For a 15 MeV 150 mA 125 ns beam in short and long pulse modes, bunch-lengths of 0.6 ps and 1 ps were measured with this method, respectively, with an error of ± 0.1 ps. Frequency measurements were also performed using a double Heterodyne system. Heterodyne measurements revealed frequency-locking, which gave a power level enhancement of 1000 at integer multiples of the Accelerator RF frequency. Frequencies up to 514 GHz were measured with a bandwidth of 25 MHz.

• Y. Fukui, D. Cline, F. Zhou
  UCLA, Los Angeles, California
• A. Aryshev, V. Karataev, T. Muto, M. Tobiyama, J.U. Urakawa
  KEK, Ibaraki
• P.R. Bolton, M.C. Ross
  SLAC, Menlo Park, California
• R. Hamatsu
  TMU, Hatioji-shi,Tokyo
• G.A. Naumenko, A. Potylitsyn, A. Sharafutdinov
  Tomsk Polytechnic University, Physical-Technical Department, Tomsk

• R. Ischebeck, C.D. Barnes, I. Blumenfeld, F.-J. Decker, M.J. Hogan, R.H. Iverson, P. Krejcik, R. Siemann, D.R. Walz
  SLAC, Menlo Park, California
• C.E. Clayton, C. Huang, D.K. Johnson, W. Lu, K.A. Marsh
  UCLA, Los Angeles, California
• S. Deng, E. Oz
  USC, Los Angeles, California
• N.A. Kirby
  Stanford University, Stanford, Califormia

The accelerating field that can be obtained in a beam-driven plasma wakefield accelerator depends on the current of the electron beam that excites the wake. In the E-167 experiment, a peak current above 10kA will be delivered at a particle energy of 28GeV. The bunch has a length of a few ten micrometers and several methods are used to measure its longitudinal profile. Among these, autocorrelation of coherent transition radiation (CTR) is employed. The beam passes a thin metallic foil, where it emits transition radiation. For wavelengths greater than the bunch length, this transition radiation is emitted coherently. This amplifies the long-wavelength part of the spectrum. A scanning Michelson interferometer is used to autocorrelate the CTR. However, this method requires the contribution of many bunches to build an autocorrelation trace. The measurement is influenced by the transmission characteristics of the vacuum window and beam splitter. We present here an analysis of materials, as well as possible layouts for a single shot CTR autocorrelator.

• R. Ischebeck, F.-J. Decker, M.J. Hogan, R.H. Iverson, P. Krejcik, R. Siemann, D.R. Walz
  SLAC, Menlo Park, California
• C.E. Clayton, C. Huang, W. Lu
  UCLA, Los Angeles, California
• S. Deng, E. Oz
  USC, Los Angeles, California
• M. Lincoln
  Stanford University, Stanford, Califormia

In the plasma wakefield acceleration experiment E-167, optical transition radiation is used to measure the transverse profile of the electron bunches before and after the plasma acceleration. The distribution of the electric field from a single electron does not give a point-like distribution on the detector, but has a certain extension. Additionally, the resolution of the imaging system is affected by aberrations. The transverse profile of the bunch is thus convolved with a point spread function (PSF). Algorithms that deconvolve the image can help to improve the resolution. Imaged test patterns are used to determine the modulation transfer function of the lens. From this, the PSF can be reconstructed. The Lucy-Richardson algorithm is used to deconvolute this PSF from test images.

• W.J. Corbett, C. Limborg-Deprey, W.Y. Mok, A. Ringwall
  SLAC, Menlo Park, California

SPEAR 3 is equipped with an x-ray pinhole camera and a visible/UV beam line to evaluate electron beam properties. The pinhole camera has a 30 x 25 micron Ta aperture and 60% image demagnification on a phosphor screen. The image is captured by a National Instruments frame-grabber on a remote computer with a parallel video signal for control room monitoring. The visible/UV beam line features a horizontal ± 0.3 mrad ‘cold finger’ to remove the x-ray core of the beam. The remaining visible/UV light is deflected 18 degrees onto an optical bench where it is focused via refractive Cassegrain optics. The beam is then split into parallel optics for gated- and streak camera measurements. This paper describes the experimental set up and preliminary measurements obtained with both systems.

• W.J. Corbett, J.A. Safranek, A. Terebilo
  SLAC, Menlo Park, California

Horizontal and vertical scraper assemblies have been installed in a standard straight section of SPEAR 3 (beta-x=10.2 m, beta-y=4.8 m, epsx=18 nm-rad, 0.1% coupling). Each scraper has stepper motor accuracy and transductor resolution on the order of 1 micron and a MATLAB/EPICS interface to simplify data acquisition. In this paper we present initial scraper measurements and analysis of the results. Of particular importance are comparison of measured dynamic aperture and momentum acceptance with model and measurement of vertical acceptance for future beam lines.

• P. Muggli
  USC, Los Angeles, California
• C.D. Barnes, M.J. Hogan, P. Krejcik, R. Siemann, D.R. Walz
  SLAC, Menlo Park, California
• R. Ischebeck, H. Schlarb
  DESY, Hamburg

Ultrashort electron bunches are now available at Stanford Linear Accelerator Center and are use mainly to produce short bursts of x-rays in a magnetic undulator and for plasma wakefield acceleration experiments. The shortest bunches have an rms longitudinal width of ˜10 microns, and a peak current of about 30 kA. Methods to measure such short bunch lengths include electro-optic modulation of a short laser pulse in a nonlinear crystal and coherent transition (CTR) autocorrelation. The transition radiation spectrum emitted by the bunches when traversing a 1 micron thin titanium foil is coherent for wavelengths longer that the bunch length and extends into the millimeter wavelength range. A CTR far-infrared autocorrelator was used to measure the bunch length as a function of the accelerator. The results obtained with this autocorrelator are the only measurements of the SLAC ultra-short bunches to date. Experimental results, as well as the limitations of the measurements and the future improvements to the autocorrelator will be presented.

• J. Carter, I.V. Agapov, G.A. Blair, G.E. Boorman, C.D. Driouichi, F. Poirier, M.T. Price
  Royal Holloway, University of London, Surrey
• K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg
  DESY, Hamburg
• S.T. Boogert, S. Malton
  UCL, London
• N. Delerue, D.F. Howell
  OXFORDphysics, Oxford, Oxon
• T.  Kamps
  BESSY GmbH, Berlin

• R.M. Lill, F. Lenkszus, E. Norum, A. Pietryla
  ANL, Argonne, Illinois

The Advanced Photon Source (APS) is a third-generation synchrotron light source in its tenth year of operation. The storage ring employs three different types of beam position monitor (BPM) systems to measure and control beam motion. The monopulse radio frequency (rf) BPM is a broadband (10 MHz) system, which is considered to be the backbone of orbit control. The rf BPM system was designed to measure single-turn and multi-turn beam positions. The rf BPMs are presently suffering from an aging data acquisition system. By replacing only the data acquisition we will revitalize this system for another decade and demonstrate a cost-effective approach to improved beam stability, reliability, and enhanced postmortem capabilities. In this paper we present the design of an eight-channel ADC/digitizer VXI board with a sampling rate of 88 MHz (per channel) and 14-bit resolution coupled with a field-programmable gate array and embedded central processing. We will discuss the upgrade system specifications, design, and prototype test results.

• A.H. Lumpkin, W. Berg, N. Sereno, C. Yao
  ANL, Argonne, Illinois

The development of nonintercepting (NI) diagnostics continues to be of interest at the Advanced Photon Source (APS) as well as elsewhere. In the three rings of the APS facility we use optical synchrotron radiation generated as the electron beam transits the dipole magnetic fields as an NI mechanism to image the beam during top-up operations. However, in the straight transport lines an alternative method is needed. Optical diffraction radiation (ODR) is under investigation to monitor 7-GeV beam trajectory and potentially transverse shape in the booster-to-storage ring (BTS) beamline during top-up operations. We have performed our initial measurements with an Al blade/mirror that served as an optical transition radiation (OTR) monitor when fully inserted into the beam and as an ODR monitor when the beam passed near the edge. In the case of ODR, appreciable signal is emitted by the metal when gamma times the reduced ODR wavelength is comparable to the impact parameter, where gamma is the Lorentz factor. Visible light optics and a standard CCD camera could thus be used for a few-mm impact parameter. We attribute the near-field signal for 1.5- to 3.0-mm impact parameters predominately to the ODR mechanism.

• A.H. Lumpkin, B.X. Yang
  ANL, Argonne, Illinois
• F. Sakamoto
  UTNL, Ibaraki

The Advanced Photon Source (APS) is a hard x-ray user facility based on a 7-GeV storage ring (SR). To accommodate the requests of the diverse user community, the APS normally runs with a 24-singlets fill pattern, a hybrid fill with a singlet and eight septuplets, or a 324-singlet fill pattern. In all cases the total stored beam current is 100 mA, with the lattice providing a natural emittance of about 2.5 nm rad. The first two patterns are used with a top-up mode that involves injection of one pulse of ~2.5 nC every two minutes into the designated SR bucket. Since the partition of bunch current varies for the different fills as well as the loading of the rf cavities, dual-sweep streak camera measurements (Hamamatsu model C5680) have been performed to characterize the average and individual bunch lengths in the fill patterns and the phase slew that occurs within the patterns. The bunch lengths vary from 32 ps (σ) within the septuplet to 50 ps (σ) for the singlet in the hybrid fill. The phase slew is significant in the hybrid fill across the eight septuplets. Example streak images of each pattern will be presented and discussed.

• B.X. Yang, J.L. Bailey, S.J. Stein, D.R. Walters
  ANL, Argonne, Illinois

The Linac Coherent Light Source (LCLS), a free-electron x-ray laser, is under design and construction. Its high intensity electron beam, 3400 A in peak current and 46 TW in peak power, is concentrated in a small area (30 micrometer rms in both horizontal and vertical directions) inside its undulator. Ten optical transition radiation (OTR) imagers are planned between the undulator segments for the characterization of the transverse profiles of the electron beam. In this paper, we present the performance requirements and technical requirements of the OTR imagers. We will discuss in detail the design of the OTR screen, the arrangement and modeling of the imaging optics, and the mechanical design and analysis of the compact camera module. Through a unique optical arrangement, this imager will achieve a fine resolution (12 micrometer rms or better) over the entire field of view (5 mm × 5 mm). The compact camera module will fit in the limited space available with remote focus adjustment. A digital camera will be used to read out the beam images in a programmable region (5 mm × 0.5 mm) at the full beam repetition rate (120 Hz), or over the entire field at a lower rate (15 Hz).

• M. Satoh, K.  Furukawa, T. Suwada
  KEK, Ibaraki

• R.B. Fiorito, A.G. Shkvarunets
  IREAP, College Park, Maryland
• T. Watanabe, V. Yakimenko
  BNL, Upton, Long Island, New York

We have performed a series of experiments using Optical Transition Radiation and Optical Diffraction Radiation Interferometry to measure the two orthogonal (x,y) rms divergences of the Brookhaven National Laboratory’s Advanced Test Facility electron beam operating at an energy of 50 MeV. Measurement of the rms divergences at the (x,y) beam waist conditions, together with corresponding measurements of the rms beam sizes allows a determination of the rms x and y emittances. A comparison of the results using OTRI and ODTRI are presented.

• S.F. Lin, H. Gao, P. Lu, B. Sun, J. Wang
  USTC/NSRL, Hefei, Anhui

Supported by Natural Science Foundation of China (10275062) and CAS Knowledge Innovation Project (KY4206).

• D. Mihalcea, C.L. Bohn
  Northern Illinois University, DeKalb, Illinois
• U. Happek
  UGA, Athens, Georgia
• P. Piot
  Fermilab, Batavia, Illinois

• M. Masaki
  JASRI/SPring-8, Hyogo

• R. Ursic, A. Kosicek
  Instrumentation Technologies, Solkan

• A. Winter
  Uni HH, Hamburg
• N. Ignashin, A. Simonov, S. Sytov
  IHEP Protvino, Protvino, Moscow Region
• E.-A. Knabbe, S. Simrock, B. Steffen
  DESY, Hamburg

• R.A. Richardson, F.W. Chambers, S. Falabella, G. Guethlein, B.A. Raymond, J.T. Weir
  LLNL, Livermore, California

A diagnostic was developed for the determination of temporal history of an X-ray spot. A pair of thin (0.5 mm) slits image the x-ray spot to a fast scintillator which is coupled to a fast detector, thus sampling a slice of the X-Ray spot. Two other scintillator/detectors are used to determine the position of the spot and total forward dose. The slit signal is normalized to the dose and the resulting signal is analyzed to get the spot size. The position information is used to compensate for small changes due to spot motion and misalignment. The time resolution of the diagnostic is about 1 ns and measures spots from 0.5 mm to over 3 mm. The theory and equations used to calculate spot size and position are presented, as well as data. The calculations assume a symmetric, Gaussian spot. The spot data is generated by the ETA II accelerator, a 2kA, 5.5 MeV, 60ns electron beam focused on a Tantalum target. The spot generated is typically about 1 mm FWHM. Comparisons are made to an X-ray pinhole camera which images the XRay spot (in 2D) at four time slices.

• N. Barov, J.S. Kim, A.W. Weidemann
  Far-Tech, Inc., San Diego, California
• R.H. Miller, C.D. Nantista
  SLAC, Menlo Park, California

Linear colliders and FEL facilities need fast, nondestructive beam position and profile monitors to facilitate machine tune-up, and for use with feedback control. FAR-TECH, Inc. is developing a resonant cavity diagnostic to simultaneously measure the dipole, quadrupole and sextupole moments of the beam distribution. Measurements of dipole and quadrupole moments at multiple locations yield information about beam orbit and emittance. The sextupole moment can reveal information about beam asymmetry which is useful in diagnosing beam tail deflections caused by short range dipole wakefields. In addition to the resonance enhancement of a single-cell cavity, use of a multi-cell standign-wave structure further enhances signal strength and improves the resolution of the device. An estimated rms beam size resolution is sub micro-meters and beam position is sub nano-meter.

• N.J. Yu, K.Y. Gong, Q. F. Li, C.-X. Tang, S. Zheng
  TUB, Beijing

• A. Drago, M.E. Biagini, S. Guiducci, C. Milardi, M.A. Preger, C. Vaccarezza, M. Zobov
  INFN/LNF, Frascati (Roma)

• P. Degtiarenko, D.W. Dotson, V.P. Popov
  Jefferson Lab, Newport News, Virginia

The new proposed method of beam position measurement is particularly suitable for monitoring high energy, and high power accelerated beams of charged particles in the vicinity of power beam dumps. Generally, the beam quality in those areas is very poor, and any equipment positioned there must be extremely resistant to radiation damage. We have found that a plate made of Chemical Vapor Deposition (CVD) Silicon Carbide (SiC) has a set of physical properties that make it suitable for such an application. CVD SiC material is a chemically inert, extremely radiation-hard, thermo-resistive semiconductor capable of withstanding working temperatures up to 2000 degrees Kelvin. It has good thermal conductivity comparable to that of Aluminum, which makes it possible to use it in high-current particle beams. High electrical resistivity of the material, and its semiconductor properties allow characterization of the position of a particle beam crossing such a plate by measuring balance of electrical currents at the plate ends. The design of a test device, and first results are presented in the report.