CERN, Geneva
EBG MedAustron, Wr. Neustadt
At CERN, the control of five of the accelerators in the injector chain (i.e. PS, PS Booster, SPS, LEIR and AD) is based upon real-time magnetic measurements in a reference magnet. These systems ("B-trains") include usually a field marker to signal the achievement of a given field value, complemented by one or more pick-up coils to integrate flux changes. Recently, some issues have been raised concerning long-term reliability and possible performance improvements, in terms of both resolution and operational flexibility, for these systems. This paper reports the results of R&D activities launched to address these concerns, namely: the development of a novel ferrite gradient compensator to enable dynamic NMR field marking in the PS' combined function magnets; and the preliminary design of a standardized electronic acquisition and conditioning system aimed at enabling the requested improvements and at facilitating rapid maintenance interventions.
CERN, Geneva
Following the analysis of the September 2008 LHC incident, the assembly process and the quality assurance of the main 13 kA interconnection splices were improved, with new measurement and diagnostics methods introduced. During the 2008-2009 shutdown ~5% of these 10 000 splices were newly assembled with these improvements implemented, but essentially maintaining the original design. It is known today that a limiting factor towards 7 TeV operation is the normal conducting resistance of ~15% of the original main 13 kA interconnection splices, associated to the electrical continuity of the copper stabiliser. A "Splices Task Force" has been set up at CERN to evaluate the need for, develop and test design improvements and prepare the implementation of a consolidation campaign. Important issues of splice design, process choice, resources and time requirements are considered.
CERN, Geneva
RAYSCAN, Meersburg
For the inspection of certain critical elements of the LHC machine a mobile computed tomography system has been developed and built. This instrument has to satisfy stringent space, volume and weight requirements in order to be usable and transportable to any interconnection location in the LHC tunnel. Particular regions of interest in the interconnection zones between adjacent magnets are the plug in modules (PIM), the soldered splices in the superconducting bus-bars and the interior of the quench diode container. This system permits detailed inspection of these regions without needing to break the cryo vacuum. Limited access for the x-ray tube and the detector required the development of a special type of partial tomography, together with suitable reconstruction techniques for 3 D volume generation from radiographic projections. We present the layout of the complete machine and the limited angle tomography as well as a number of radiographic and tomographic inspection results.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
The Marie Curie Initial Training Network DITANET covers the development of advanced beam diagnostic methods for a wide range of existing or future accelerators, both for electrons and ions. The network brings together research centres like CERN or DESY, Universities, and private companies. DITANET currently has 27 partners from Europe and the USA and is committed to training young researchers in this field, performing cutting edge research in beam instrumentation, and exploiting synergies within this community. This contribution presents an overview of the research outcomes within the first two years of DITANET and summarizes the network's training activities.
on behalf of the DITANET Consortium.
Cockcroft Institute, Warrington, Cheshire
INFN/LNS, Catania
The University of Liverpool, Liverpool
Future atomic and nuclear physics experiments put challenging demands on the required beam instrumentation. Low energy (<1 MeV), low intensity (<107 pps) beams will require highly sensitive monitors. This is especially true for the Facility for Low-energy Antiproton and Ion Research (FLAIR) where antiproton beams will be decelerated down to 20 keV and as few as 5·105 particles per second will be slowly extracted for external experiments. In order to investigate the limits of scintillating screens for beam profile monitoring in the low energy, low intensity regime a structured analysis of several screen materials, including CsI:Tl, YAG:Ce and scintillating fibre optic plate (SFOP), has been done under different irradiation conditions with keV proton beams. This contribution will present the experimental setup and summarize the results of this study.
TRIUMF, Vancouver
The ISAC accelerators presently deliver various stable and radioactive CW heavy ion beams to experiments with energies ranging from 2keV/u up to about 4.5 MeV/u ( for A/q = 6 ). Beam intensities also vary enormously being as low as a few hundred ions per second for certain radioactive ion species and as high as 100 enA for stable and pilot beams. Monitoring of beams with currents of less than ~0.5 epA requires a dedicated diagnostics instrumentation which typically makes use of radiation hard single particle detectors. Several such devices have been built and are under development at TRIUMF. Electron multiplier based SEEM monitors, solid state and scintillator detectors with a count rate capability in excess of 106 pps are employed. Device controls are integrated into the EPICS environment and provide standardized, simple and transparent operation. Details of the design, tests and beam measurements will be present.
HIP, University of Helsinki
Comenius University in Bratislava, Faculty of Mathematics Physics and Informatics, Bratislava
Helsinki University, Department of Physics, University of Helsinki
The Super-FRS is a superconducting fragment separator that will be built as part of the FAIR facility. For the slow-extraction part of the beam diagnostics system a total of 32 detectors are needed for beam monitoring and for tracking and characterization of the produced ions. Since GEM-TPC detectors can perform over wide dynamic range without disturbing the beam, they are suitable for this kind of in-beam detection. We have studied the performance of a prototype GEM-TPC. The current status of the prototype detector and the measurement results are shown.
DESY, Hamburg
IKP, Mainz
Luminescent screens are widely used for particle beam diagnostics, especially in transverse profile measurements at hadron machines and low energy electron machines where the intensity of optical transition radiation (OTR) is rather low. The experience from modern linac based light sources showed that OTR diagnostics might fail even for high energetic electron beams because of coherence effects in the OTR emission process. An alternative way to overcome this limitation is to use luminescent screens, especially inorganic scintillators. However, there is only little information about scintillator properties for applications with high energetic electrons. Therefore a test experiment has been performed at the 855 MeV beam of the Mainz Microtron MAMI (University of Mainz, Germany) in order to study the spatial resolution. The results of this experiment will be presented and discussed in view of scintillator material properties and observation geometry.
DESY, Hamburg
BNL, Upton, Long Island, New York
TUD, Dresden
DESY Zeuthen, Zeuthen
PETRA III is the new 3rd generation hard X-ray synchrotron light source at DESY, operating at a beam energy of 6 GeV. Machine commissioning began in April 2009 and user operation starts in 2010. In order to achieve a high brilliance, damping wigglers with a total length of 80 m are installed to reduce the horizontal emittance down to an extremely low value of 1 nm rad. For a precise emittance online control, a dedicated diagnostics beamline was built up to image the beam profile with synchrotron radiation from a bending magnet in the X-ray region. The beamline is equipped with two interchangeable X-ray optical systems, a pinhole optic for standard operation and a high resolution compound refractive lens optic. In addition, the synchrotron radiation angular distribution can be exploited at high photon energies. In this presentation, first experience with the system will be reported.
MPI-K, Heidelberg
Kyoto ICR, Uji, Kyoto
A cryogenic storage ring (CSR) is under construction at MPI für Kernphysik, which will be a unique facility for low velocity phase space cooled ion beams. Among other experiments the cooling and storage of molecular ions in there rotational ground state is planed. To meet this requirement the ring must provide a vacuum with a residual gas density below 10000 molecules/cm3, which will be achieved by cooling the vacuum chamber of the ion beam to 2-10 K. The projected stored beam current will be in the range of 1 nA - 1 μA. The resulting low signal strengths on the beam position pickups, current monitors and Schottky monitor put strong demands on these diagnostics tools. The very low residual gas density of the CSR does not allow using a conventional residual gas monitor to measure the profile of the stored ion beam. Other methods were investigated to measure the profile of a stored ion beam. In the paper an overview of the CSR diagnostics tool and diagnostics procedures will be given.
INFN/LNF, Frascati (Roma)
Università degli Studi di Firenze, Firenze
INOA, Firenze
VIGO System S.A., Ozarow Maz.
At the LNF of INFN an IR array detector with a ns response time has been built and assembled in order to collect the IR image of the e-/e+ sources at DAΦNE. Such detector is made by 32 bilinear pixels with a pixel size of 50x50 μm2 and a response time of 1 ns. The device with its electronic board has been assembled for the installation on the e+ ring of DAΦNE in the framework of an experiment funded by the INFN Vth Committee dedicated to beam diagnostics. A preliminary characterization of few pixels of the array and of the electronics has been carried out at the IR beamline SINBAD at DAΦNE. In particular the detection of the IR source of the e- beam has been observed using four pixels of the array acquiring signals simultaneously with a 4 channels scope at 1GHz and at 4 Gsamples/s. The acquisition of 4 pixels allowed monitoring in real time differences in the bunch signals in the vertical direction. Preliminary analysis of data is presented and discussed. In particular we will outline how the differences in the signals can be correlated to small displacements of the source after the bunch refilling and during a complete shift of DAΦNE and before the refilling of electrons.
RIKEN/SPring-8, Hyogo
JASRI/SPring-8, Hyogo-ken
We report the design, performance, and installation of the beam diagnostic system of XFEL/SPring-8. The electron beam bunches of an XFEL accelerator are compressed from 1 ns to 30 fs by bunch compressors without emittance growth and peak-current fluctuation which directly cause SASE fluctuation. To maintain the stable bunch compression process, the accelerator requires rf caivty beam position monitors (BPM) with 100 nm resolution, OTR screen monitors (SCM) with a few micro-meter resolution, fast beam current monitors (CT) and temporal structure measurement systems with resolution under picosecond. The performance of the developed monitor instruments, such as the BPM, the SCM, and the CT, was tested at the SCSS test accelerator and satisfied with the requirements. To measure the temporal structure of the electron bunch, three type measurement systems, which are a streak camera, an EO sampling measurement, and a transverse deflecting cavity with a resolution of few-tens femtosecond, are being prepared. The streak camera and EO sampling shows the resolution of sub-picosecond. The installation of these beam diagnostic systems is going on smoothly.
KEK, Ibaraki
MELCO SC, Tsukuba
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
To maintain the beam orbit of beam transport line from RCS to MR in J-PARC (3-50BT), 14 beam position monitors (BPMs) were installed. Their signals gathered in the local control building (D01) have been measured by using 14 digitizing oscilloscopes. The data acquisition system have a performance of shot-by-shot measurement.
SESAME, Amman
SESAME machine consists of a 22.5 MeV microtron, 800 MeV booster and a 2.5 GeV storage ring. The electron beam diagnostics will play a major rule during the commisioning and normal operation with different modes of single bunch and multi bunch operations. Furthermore the beam parameteres during injection, acceleration and storing the beam will be measured, monitored and integrated into other subsystems. The major diagnostics components and the general design for booster and storage ring are reported in this paper.
TUB, Beijing
The coherent Smith-Purcell radiation (CSPR) has been demonstrated as an efficient technique for measuring the longitudinal profile of beam bunches. To measure the ultrashort beam bunches, the simulations for the measurements using CSPR are anlyzed with tools of three dimensional particle-in-cell simulations and Kramer-Kronig reconstruction. Different parameters such as rms length of beam bunch and profiles of grating are studied. Furthermore, the measurement device based on a Martin-Puplett Interferometer is introduced, in which noises and attenuation can be reduced.
USTC/NSRL, Hefei, Anhui
GigE Vision (Gigabit Ethernet vision standard) is a new interface standard for the latest vision of cameras with higher performance compared to analogue vision standard and other digital vision standard. In recent years, the market of industrial vision components is evolving towards GigE Vision. This paper presents applications of digital camera comply with GigE Vision standard for the measurement of beam profile and emittance at the storage ring of HLS (Hefei Light Source). These cameras provide low distortion for image transmission over long distance with high image rate. Using the image of beam profile transmitted by GigE Vision digital camera, we calculated the horizontal and vertical center positions, and then we calibrated these center positions by BPM (Beam Position Monitor) system. According to the result of calibration and the pixel size of CCD sensor, transverse sizes of beam profile were calculated, further more the transverse emittance and coupling factor were calculated as well.
SINAP, Shanghai
A new beam profile diagnostic system based on industrial Ethernet has been installed in Shanghai Deep Ultraviolet Free Electron Laser (SDUV-FEL) facility recently. By choosing GigE Vision cameras, the system provides better image quality over a long distance than before. Beam images are captured from the beam profile monitors which are controlled by air cylinders or step motors. In order to fit for the system expansibility and curtail the cables, all devices are operated through the Ethernet and distributed along the FEL facility. The approach to the design of the hardware and software will be described in this paper. Applications and experiment results will be shown in this paper as well.
Saint-Petersburg State University, Saint-Petersburg
LETI, Saint-Petersburg
We describe both analytically and numerically beams radiation in presence of media which can be realized as modern metamaterials. In particular, effects of reversed Cherenkov radiation (RCR)* and reversed Cherenkov-transition radiation (RCTR)** are considered. These phenomena can be used for detection of charged particles and diagnostics of beams. Earlier we noted some useful properties of radiation in the case of the boundary between an ordinary medium and an isotropic left-handed metamaterial (LHM)*. Now we continue to analyze prospects of use of LHM for beam diagnostics. Moreover, we investigate RCR and RCTR in the case of certain anisotropic materials with properties being similar to properties of LHM. The useful features are reversed character of radiation and, particularly, existence of two thresholds for RCTR (lower threshold and upper one). This fact allows selection of particles (or beams) with energy in some predetermined range. The specific radiation patterns (having two or three lobes in anisotropic metamaterial) can be useful for particle energy measurement as well.
* Z.Y. Duan, B.-I. Wu, S. Xi, H.S. Chen., M. Chen, Progress in Electromagn. Research, v.90, p.75 (2009).
** S.N. Galyamin, A.V. Tyukhtin, A. Kanareykin, P. Schoessow, PRL, v.103, p.194802 (2009).
Saint-Petersburg State University, Saint-Petersburg
Euclid TechLabs, LLC, Solon, Ohio
We consider the particles energy measurement method offered in our papers (footnotes). It is based on measurement of the modes frequencies in waveguide loaded with certain material. For this method, the modes frequencies must depend on the particles energy strong enough. Here we discuss the problem of selection of materials for this technique. It is shown that high precision of energy measurement can be reached by use of the system of specific parallel conductors. The approximate analytical approach for obtaining effective permittivity of such structure is developed. It is shown that selection of parameters of the structure allows ruling an effective permittivity characterized by both frequency dispersion and spatial one. The structure is simple enough for production. It allows measuring the particles energy for different predetermined ranges. The other ways of realization of the method are discussed as well. One of them consists in use of thin layer of ordinary dielectric. Selection of the layer thickness and dielectric constant allows obtaining strong enough dependence of frequency on Lorentz-factor in the relatively wide range.
A.V. Tyukhtin, S.P. Antipov, A. Kanareykin, P. Schoessow, PAC07, p.4156;
A.V. Tyukhtin, EPAC08, p.1302;
A.V. Tyukhtin, Technical Physics Letters, v.34, p.884 (2008), v.35, p.263 (2009).
TPU, Tomsk
Tomsk Polytechnic University, Nuclear Physics Institute, Tomsk
A noninvasive technique to determine a sub-mm length of electron bunches (rms < 100 um) based on a measurement of the coherent Cherenkov radiation (CChR) spectrum in THz range is proposed. CChR is generated when electron bunch moves in a vacuum near dielectric target. If the optical properties and geometry of a target are chosen in order to achieve a low absorption with a dispersion allowing expanding the Cherenkov cone, such target may be considered as the «natural Cherenkov prism». We demonstrated a feasibility of using of CsI prism for measurement of a bunch length in the range 50-200 um for Lorentz factor = 100. We also measured CChR power from Teflon target generated by the 6.1 MeV bunched electron beam with bunch rms length 1.2 mm and compared it with coherent diffraction radiation one for identical conditions. CChR seems to be a promising radiation mechanism for a new beam diagnostics technique.
IFIC, Valencia
SLAC, Menlo Park, California
In this paper we describe the design, installation and first calibration tests of a Multi Optical Transition Radiation (OTR) monitor system in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. This system will be a valuable tool for measuring beam sizes and emittances from the ATF Damping Ring (DR). With an optical resolution of about 2 um an original OTR design demonstrated the ability to measure a 5.5um beam size in one beam pulse and to take many fast measurements. This gives the OTR the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter. Furthermore the near by wire scanners will be a definitive test of the OTR as a beam emittance diagnostic device. The muti-OTR system design proposed here is based on the existing OTR1X, located after the septums at the entrance of the EXT line.
CERN, Geneva
EPFL, Lausanne
Uppsala University, Uppsala
The University of Liverpool, Liverpool
The CTF3 facility is being built and commissioned by an international collaboration in order to test the feasibility of the proposed CLIC drive beam generation scheme. Central to this scheme is the use of RF deflectors to inject bunches into a Delay Loop and a Combiner Ring, in order to transform the initial bunch spacing of 1.5 GHz from the linac to a final bunch spacing of 12 GHz. The optimization procedure relies on several steps. The active length of each ring is carefully adjusted to within a few millimeters accuracy using a two‐period undulator. The transverse optics of the machine must be set-up in a way so as to ensure the beam isochronicity. Diagnostics based on optical streak cameras and RF power measurements have been designed to measure the longitudinal behaviour of the beam during the combination. This paper presents their performance and highlights recent measurements.
CERN, Geneva
University of Oslo, Oslo
The CLIC study is based on the so‐called two‐beam acceleration concept and one of the main goals of the CLIC Test Facility 3 is to demonstrate the efficiency of the CLIC RF power production scheme. As part of this facility a Test Beam Line (TBL), presently under commissioning, is a small scale version of a CLIC decelerator. To perform as expected the beam line must show efficient and stable RF power production over 16 consecutive decelerating structures. As the high intensity electron beam is decelerated its energy spread grows by up to 60%. A novel segmented beam dump for time resolved energy measurements has been designed to match the requirements of the TBL. As a complement, a diffusive OTR screen is also installed in the same spectrometer line. The combination of these two devices will provide both a high spatial resolution measurement of both the energy and energy spread and a measurement with a few nanoseconds time response. This paper describes the design of the new segmented dump and presents the results from the first commissioning of the TBL spectrometer line.
PSI, Villigen
ORNL, Oak Ridge, Tennessee
Operation and upgrade of very intense proton beam accelerators like the PSI facility and the SNS spallation source at ORNL is typically constrained by potentially large machine activation. Besides the standard beam diagnostics, beam tomography techniques provide a reconstruction of the beam transverse phase space distribution, giving insights to potential loss sources like irregular tails or halos. Unlike more conventional measurement approaches (pepper pot, slits) beam tomography is a non destructive method that can be performed at high energies and, virtually, at any beam location. Results from the application of the Maximum Entropy Tomography (MENT) algorithm to different beam sections at PSI and SNS will be shown. In these reconstructions the effect of nonlinear forces is made visible in a way not otherwise available through wire scanners alone. These measurements represent a first step towards the design of a beam tomography implementation that can be smoothly employed as a reliable diagnostic tool.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
We present preliminary results of beam diagnostics for the world's first Non-Scaling FFAG Accelerator 'EMMA'. Amongst other means, a single-shot/turn-by-turn BPM system is used, that was first tested on the ALICE injector. The BPM system utilizes a front-end conversion of button pickup signals into flat-top-envelope 700 MHz bursts, time-domain multiplexing (in each plane, signals are made spaced by 13.8 ns), and the manufacture of both synchronous detector and ADC clocks directly from the beam signal. The system performance is discussed; results of beam-based resolution measurement are given. First turn beam trajectories furthest from the Septum and Kicker are presented.
The University of Liverpool, Liverpool
MPI-K, Heidelberg
Cockcroft Institute, Warrington, Cheshire
Supersonic gas-jets have attracted much interest as experimental targets in several fields of science since they combine low internal temperatures with high directionality. Axisymmetric jets have found widespread application, triggering a wealth of studies on their properties, while only a limited number of detailed studies have been done on planar jets. In this paper, the design of a beam profile monitor based on a planar supersonic gas-jet for use in the Ultra-low energy Storage Ring (USR) at the Facility for Antiproton and Ion Research (FAIR) in Germany is described. Optimization of the monitor requires investigation into different characteristic jet parameters. For that purpose extensive simulation work with the Gas Dynamics Tool (GDT) was done. The results of these studies are presented together with a description of a novel nozzle-skimmer configuration and an experimental test stand to benchmark the numerical results.
JAI, Oxford
We report on the possible utilisation of Smith-Purcell radiation to measure the longitudinal profile of 50-femtoseconds electron bunches. This length is typical for the bunches currently produced by Laser Wakefield Acceleration and is at the limit of what is achievable by alternative techniques, such as Electro-Optic sampling.
Diamond, Oxfordshire
University of Oxford, Clarendon Laboratory, Oxford
JAI, Oxford
Single shot emittance measurement is essential to assess the performance of new generation light sources such as linac based X-ray FELs or laser plasma wakefield accelerators. To this aim, we have developed a single shot emittance measurement using at least 3 screens inserted in the beam at the same time, measuring the beam size at different positions in a drift space in one shot. We present here test measurements performed at Diamond in the transfer line from the Booster to the Storage Ring, using thin OTR and also YAG screens. We also compare these measurements with results from the more conventional quadrupole scan method and also measurements using an OTR screen and an assembly of two cameras imaging the beam size and the beam divergence at a point near the waist of the beam. The validity and limits of the new method are discussed in the paper.
RadiaBeam, Marina del Rey
UCLA, Los Angeles, California
For successful operation and beam characterization, fourth generation light sources require the observation of sub-picosecond bunches with femtosecond resolution. In this paper, we report on the design and development of a novel technique to achieve sub-femtosecond temporal resolution of high brightness bunches. The technique involves the coupling of the electron beam to a high power laser in an undulator field, which is optimized to maximize the angular deviation of the bunch. The beam angular components are imaged on a distant screen yielding a sweep across angles in one dimension. The addition of an x-band deflecting cavity downstream of the undulator creates another sweep of the beam, in the perpendicular dimension. The temporal resolution of the bunch is dependent on the seed laser wavelength and the spatial resolution of the screen. Initial calculations show that for a CO2 laser (T~30fs) and a phosphor screen (~50micron spatial resolution), the longitudinal resolution is approximately l/200 of the laser wavelength, or ~150 attoseconds.
RadiaBeam, Marina del Rey
NRL, Washington D.C.
A beam profile monitor utilizing the technological advances in fiber optic manufacturing to obtain micron level resolution is under development at RadiaBeam Technologies. This fiber-optic profiling device would provide a lost cost, turn-key solution with nominal operational supervision and requires minimal beamline real estate. We are currently studying and attempting to mitigate the technical challenges faced by a fiber optic based diagnostic system with a focus on radiation damage to the fibers and its effect on signal integrity. Preliminary irradiation studies and conceptual operation of the system are presented.
RadiaBeam, Marina del Rey
INFN/LNF, Frascati (Roma)
UCLA, Los Angeles, California
BNL, Upton, Long Island, New York
The quest for detailed information concerning ultra-fast beam configurations, phase spaces and high energy operation is a critical task in the world of linear colliders and X-ray FELs. Huge enhancements in diagnostic resolutions are represented by RF deflectors. In this scenario, Radiabeam Technologies has developed an X-band Travelling wave Deflector (XTD) in order to perform longitudinal characterization of the subpicosecond ultra-relativistic electron beams. The device is optimized to obtain a single digit femtosecond resolution using 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory; however, the design can be easily extended to be utilized for diagnostics of GeV-class beams. The XTD design fabrication and tuning results will be discussed, as well as installation and commissioning plans at ATF.
* J. England et al., "X-Band Dipole Mode Deflecting Cavity for the UCLA Neptune Beamline".
** D. Alesini, "RF deflector-based sub-ps beam diagnostics: application to FELs and advanced accelerators".
RadiaBeam, Marina del Rey
BNL, Upton, Long Island, New York
For high average current electron accelerators, such as Energy Recovery Linacs (ERL), the characterization of basic electron beam properties requires non-interceptive diagnostics. One promising non-destructive approach for a high average current beam diagnostic is the laser wire scanner (LWS). RadiaBeam Technologies is developing an inexpensive, stand-alone laser wire scanner system specifically adapted to ERL parameters. The proposed system utilizes distinctive features of ERL beams, such as a relatively long bunch length and ultra-high repetition rate, to maximize photon count while using off the shelf laser technology. The RadiaBeam LWS prototype presently under development will be installed and commissioned at the Brookhaven National Laboratory (BNL) ERL facility. This system's design and projected performance are discussed herein.
RadiaBeam, Marina del Rey
Spectrum Detector, Lake Oswego, Oregon
UGA, Athens, Georgia
PSI, Villigen
This paper reports on the progress of the development of a bunch length diagnostic for high brightness beams. The diagnostic, termed the real time interferometer, is a single shot, autocorrelator that outputs the interferogram of coherent radiation emitted from compressed, high-brightness beams. The device uses all-reflective terahertz optics as well as a highly sensitive pyroelectric-based detector array. For initial testing, coherent transition radiation is used, however, the diagnostic can be used in a non-destructive manner if coherent edge or synchrotron radiation is employed. Current research includes diagnostic design and preliminary tests conducted at the BNL Accelerator Test Facility.
SINAP, Shanghai
Shanghai KEY Laboratory of Cryogenics & Superconducting RF Technology, Shanghai
The digital low level radio frequency (DLLRF) system and the beam trip diagnostic system in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been operational for more than one year. The DLLRF has successfully maintained the amplitude and phase stability of the cavity field in the superconducting cavity even when the beam current in the storage ring reached 300mA at 3.5GeV, and the beam trip diagnostic system has been realized and is helpful for improving the reliability of the RF system.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
I-Tech, Solkan
The Low Level RF (LLRF) control system on EMMA (Electron Model for Many Applications), the world's first Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) accelerator is presently being installed and commissioned at Daresbury Laboratory. The LLRF is required to synchronize with ALICE (Accelerators and Lasers in Combined Experiments) its injector, which operates at 1.3GHz, and to produce an offset frequency as required (+1.5Mhz to -4MHz) to then maintain the phase and amplitude of the 19 copper RF cavities of the EMMA machine. The design and commissioning of the LLRF system is presented.
CERN, Geneva
Phase II collimators will complement the existing system to improve the expected high RF impedance and limited efficiency of Phase I jaws. An international collaborative effort has been launched to identify novel advanced materials responding to the very challenging requirements of the new collimators. Complex numerical calculations simulating extreme conditions and experimental tests are in progress. In parallel, an innovative modular design concept of the jaw assembly is being developed to allow fitting in alternative materials, minimizing the thermally induced deformations, withstanding accidents and tolerate high radiation doses. Phase II jaw assembly is made up of a molybdenum back-stiffener ensuring high geometrical stability and a modular jaw split in threes sectors. Each sector is equipped with a high-efficiency independent cooling circuit. Beam position monitors (BPM) are embedded in the jaws to accelerate setup time and improve beam monitoring. An adjustment system will permit to fine-tune the jaw flatness just before commissioning the system. A full scale collimator prototype is being manufactured by CERN workshops to validate each feature of the new design.
INFN/LASA, Segrate (MI)
The production of Cs2Te photoemissive films used as laser driven electron sources in the high brightness photoinjectors at FLASH and PITZ, is a well established activity at INFN Milano since the '90s. Our total production is of more than 100 photocathodes, with an average QE of 8% (@ 254 nm) for fresh films and an operative lifetime that increased up to some months at FLASH. In the last two years, we have improved the standard diagnostic used during the cathode growth to better understand the material properties of the films. This activity is motivated by the need to improve the photocathode properties, mainly the energy distribution of the photoemitted electrons that influences the thermal emittance. The multiwavelengths diagnostic, i.e. the on-line measurements of the photocurrent and reflectivity from the film during its growth in the 239 nm ~ 436 nm range, has been deeply applied on several cathodes and the potentiality of this technique are discussed in this paper.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
Cockcroft Institute, Warrington, Cheshire
JAI, Oxford
The design of free electron laser (FEL) driver needs careful beam transport design to pass very short bunches through the switchyard/spreader to switch the beam to different FEL lines. The spreader design which allows flexibility in operation has been adapted following the LBNL design*. In order to measure the slice properties of the bunches two beam diagnostics lines are proposed, a straight one for beam commissioning purposes and a branch of the spreader similar to the FEL lines to measure the adverse effects that may arise due to passing the short bunches through the kicker and septum magnets. As a part of machine protection, post linac collimation system collimates the halo particles in transverse and energy planes. The design of the collimation, beam spreader and beam diagnostics lines is discussed.
* Zholents A.A. et al, CBP Tech Note 401, 2009
SLAC, Menlo Park, California
BNL, Upton, Long Island, New York
Life Imaging Technology, Palo Alto, California
As SPEAR3 moves closer to trickle-charge topup injection, the complex phase-space dynamics of the injected beam becomes increasingly important for capture efficiency and machine protection. In the horizontal plane the beam executes ~12mm betatron oscillations and begins to filament within 10's of turns. In the vertical plane the beam is more stable but a premium is placed on flat-orbit injection through the Lambertson septum and the correct optical match. Longitudinally, energy spread in the booster is converted to arrival-time dispersion by the strong R56 component in the transfer line. In this paper, we report on turn-by-turn imaging of the injected beam in both the transverse plane and in the longitudinal direction using a fast-gated ccd and streak camera, respectively.
BNL, Upton, Long Island, New York
The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster synchrotron and associated transport lines. The transport lines need to transport the beam from the linac to the booster and from the booster to the storage ring in a way that provide high injection efficiency. In this paper we discuss progress on specifying and prototyping the NSLS-II transfer lines including diagnostics, magnet specifications, and safety systems. Commissioning plans are also discussed.
JASRI/SPring-8, Hyogo-ken
This presentation will cover the topics of synchrotron radiation monitors for light sources, including transverse beam profile measurement, longitudinal bunch profile measurement, and bunch purity measurement. It will also cover developments of beam diagnostics based on observation of x-rays from a dedicated insertion device.
KEK, Ibaraki
Kanto Information Service (KIS), Accelerator Group, Ibaraki
ACMOS INC., Tokai-mura, Ibaraki
J-PARC, KEK & JAEA, Ibaraki-ken
The beam commissioning of the J-PARC Main Ring started in May, 2008. Data archive system has been developed using Channel Archiver, which is a tool developed and maintained in the EPICS community. Various machine parameters and status information of Main Ring have been recorded. The number of records registered extends 17,000 as of December, 2009. The archive data can be retrieved in a form of graphical representation by Web browser. In addition, the mechanism to provide bit-type information, such as interlock and on/off, in time series format is available. They have been used in daily operation of Main Ring. Addition to them, we are trying to develop a new scheme to record large waveform data of beam diagnostic signals. Status and progress of the archive system will be discussed.
SINAP, Shanghai
Soft IOC is an ideal solution for high level global application of accelerator control and beam diagnostics due to easy online modification and rebooting. SSRF beam diagnostics system employees two soft IOCs to handle global tasks such as BPMs group access, orbit performance analyze and online data reliability analyze, which are hardly performed in bottom level IOC side and OPI side. This paper introduces the current status and future upgrade plan.
NSRRC, Hsinchu
Modbus-TCP is a widely used in industry for a long time and accelerator control system recently. Modbus protocol over Ethernet has advantages for non real-time applications due to its maturity. The TPS (Taiwan Photon Source) project will have many Modbus-TCP enable devices which distributed in utility system and accelerator system. The accelerator control environment of TPS project is an EPICS toolkit based system. Modbus-TCP might adopt for some subsystems. There are several possible Modbus-TCP devices including the prototype power supply for magnet field mapping application equip with Modbus-TCP interface, vacuum system local controller, front-end controller, and some monitoring devices. In this paper, we will summarise preparation efforts to accommodate the Modbus-TCP support in the TPS control system.
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin
In view of increased processing bandwidth at demanding experiments and the need for rapid compensation of noise spikes and new, yet unknown excitations a fast orbit feedback aiming at noise suppression in the 1Hz-50Hz range has become mandatory for the 3rd generation light source BESSY II. As a first step the fast setpoint transmission plus the replacement of all corrector power supplies is foreseen. Later - in combination with top-up operation - orbit stability can be further improved by replacing today's multiplexed analog beam position monitors by parallel processing fast digital units. This paper describes how the pilot installation of a small subset of fast corrector power supplies already allows to tune performance and study the benefits for today's most sensible experiments.
CERN, Geneva
The LHC deploys a comprehensive suite of beam-based feedbacks for safe and reliable machine operation. This contribution summarises the commissioning and early results of the LHC feedback control systems on orbit, tune, chromaticity, and energy. Their performance – strongly linked to the associated beam instrumentation, external beam perturbation sources and optics uncertainties – is evaluated and compared with the feedback design assumptions.
Diamond, Oxfordshire
We present our observations of the medium term and long term stability of the photon beams at Diamond Light Source. Drift of the Electron Beam Position Monitors results in real X-ray beam movements, observed by both Front End X-ray Beam Position Monitors and beamline scintillator screens on some beamlines. We discuss how we are using these diagnostics tools to measure and characterise the drift. Medium term movements related to top-up cycles are seen, believed to be caused by changes to single bunch charge, and the long term drift of the electron beam position over several days and weeks is examined. A slow feedback system using X-ray Beam Position Monitors has been shown to successfully correct this drift. The results of these trials are presented.
ANL, Argonne
The Advanced Photon Source (APS) real-time orbit feedback system is complex and faults are difficult to diagnose. This paper presents a diagnostic method based on fault tree analysis (FTA). The fault tree is created based on more than ten years operating experience of the system. The method is described to analyze the fault tree. The operator interface to the diagnostic tool is discussed.
CERN, Geneva
Cockcroft Institute, Warrington, Cheshire
The Compact Linear Collider (CLIC) is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel two-beam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. A particular attention is given to the two-beam module where the protection from beam losses is particularly challenging and important.
MPI-K, Heidelberg
UMD, College Park, Maryland
Cockcroft Institute, Warrington, Cheshire
Beam halo can have severe effects on the performance of high energy accelerators. It reduces the experimental throughput, may lead to noise in the experiments, or even damaging of accelerator components. In order to understand and ideally control the formation and evolution of beam halo, detailed simulation studies are required. In this contribution halo generation mechanisms and the underlying physical principles are first presented, before the particular case of the CLIC Test Facility (CTF3) is discussed in detail. Analytical, numerical and simulation studies are combined to estimate the relevant sources of halo formation and to study halo propagation in the different CTF3 sections.
KEK, Ibaraki
JAEA/ERL, Ibaraki
ISSP/SRL, Chiba
We are developing the superconducting (SC) cavity for Energy Recovery Linac (ERL) in Japan. In order to survey the electron emission and the heating spot of the cavity inner surface in detail, cavity diagnostics with the rotating mapping system was applied. Two types of sensors, one of which is the carbon resistor and the other is the Si PIN photo diode, were set to detect the temperature rise and electron emission. By rotating the sensor arrays around the cavity axis, a lot of information is obtained all over the cavity surface in detail. This paper reports the results of vertical tests by using this rotating mapping system with Nb 9-cell ERL cavity.
ODU, Norfolk, Virginia
JLAB, Newport News, Virginia
The tomographic reconstruction of local plasma parameters for nonequilibrium plasma sources is a developing approach, which has a great potential in understanding the fundamental processes and phenomena during plasma processing of SRF cavity walls. Any type of SRF cavity presents a plasma rector with limited or distorted symmetry and possible presence of high gradients. Development of the tomographic method for SRF plasma analysis consists of several steps. First, we define the method based on the inversion of the Abel integral equation for a hollow spherical reactor. Second step is application of the method for the actual elliptical cavity shape. Third step consists of study of the effects of various shapes of the driven electrode. Final step consists of testing the observed line-integrated optical emission data. We will show the typical results in each step and the final result will be presented in the form of correlation between local plasma parameter distributions and local etching characteristics.
Karlsruhe Institute of Technology (KIT), Karlsruhe
CERN, Geneva
BNG, Würzburg
STFC/RAL, Chilton, Didcot, Oxon
INFN/LNF, Frascati (Roma)
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
Diamond, Oxfordshire
UMAN, Manchester
Rome University La Sapienza, Roma
MAX-lab, Lund
Max-Planck Institute for Metal Research, Stuttgart
One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source DIAMOND is under discussion. Here we describe the technical design report of this device and the planned measurements with beam.
OXFORDphysics, Oxford, Oxon
JAI, Oxford
We present the results of the development of a high power fibre laser system for the laserwire project to measure very low emittance electron beams. We use the output of a commercial 1uJ, 6.49MHz laser system and amplify it in rod type photonic crystal fibre. This is a novel form of optical fibre which has a large core diameter (70um) but still supports only a single Gaussian spatial mode, essential for focusing the beam to the smallest spot size and achieving the highest resolution. We amplify the seed pulses in a burst mode suitable for use in a linear accelerator, which has the advantage of decreasing the pump power required and thus reducing the running cost and heat loading of the laser system. The amplified pulses have energies of ~ 100uJ in the near infrared and excellent beam quality, as specified in the original design, and are frequency converted to the green to give sub-micron spatial resolution.
SLAC, Menlo Park, California
SLAC National Accelerator Laboratory has built and is currently operating a first generation prototype Marx klystron modulator to meet ILC specifications. Under development is a second generation prototype, aimed at improving overall performance, serviceability, and manufacturability as compared to its predecessor. It is designed around 32 cells, each operating at 3.75 kV and correcting for its own capacitor droop. Due to the uniqueness of this application, high voltage gate drivers needed to be developed for the main 6.5 kV and droop correction 1.7 kV IGBTs. The gate driver provides vital functions such as protection of the IGBT from over-voltage and over-current, detection of gate-emitter open and short circuit conditions, and monitoring of IGBT degradation (based on collector-emitter saturation voltage). Gate drive control, diagnostic processing capabilities, and communication are digitally implemented using an FPGA. This paper details the design of the gate driver circuitry, component selection, and construction layout. In addition, experimental results are included to illustrate the effectiveness of the protection circuit.
KEK, Ibaraki
Vertical test for 1.3GHz 9-cell cavity has been routinely carried out over one year since 2008 in KEK-STF. Temperature mapping (T-mapping) system using 352 carbon resistors was introduced to identify the heating location at thermal quenching of the cavity. T-mapping system in STF identified perfectly the heating location in every vertical test for S1-Global project. As X-ray-mapping system, 142 PIN diodes were used, and the x-ray emission site was detected under heavy field emission. During the vertical test, it is convenient to display the result of T-mapping and X-ray-mapping by online monitor system. For this purpose, the new online monitor system was developed by using EPICS (Experimental Physics and Industrial Control System) and Java script, and introduced in recent several vertical tests. As a data acquisition system, nine data loggers (MW100, YOKOGAWA) are used, and signals from totally 540 channels are stored every 0.1 sec. The online display for T-mapping and X-ray-mapping is updated automatically every 5 seconds. In this report, the summary of T-mapping/X-ray-mapping result and the online monitor system will be described in detail.
SLAC, Menlo Park, California
A Marx-topology klystron modulator is under development for the International Linear Collider (ILC) project*. It is envisioned as a lower cost, smaller footprint, and higher reliability alternative to the present, bouncer-topology, baseline design. The application requires 120 kV (±0.5%), 140 A, 1.6 ms pulses at a rate of 5 Hz. The Marx constructs the high voltage pulse by combining, in series, a number of lower voltage cells. The Marx employs solid state elements; IGBTs and diodes, to control the charge, discharge and isolation of the cells. Active compensation of the output is used to achieve the voltage regulation while minimizing the stored energy. The developmental testing of a first generation prototype, P1, has been completed. This modulator has been integrated into a test stand with a 10 MW L-band klystron, where each is undergoing life testing. Development of a second generation prototype, P2, is underway. The P2 is based on the P1 topology but incorporates an alternative cell configuration to increase redundancy and improve availability. Status updates for both prototypes are presented.
* ILC Reference Design Report, http://www.linearcollider.org/cms/?pid=1000437
IIT, Chicago, Illinois
Fermilab, Batavia
ANL, Argonne
Muon cooling requires high-gradient normal conducting cavities operating in multi-Tesla magnetic fields for muon beam focusing in an ionization cooling channel. Recent experience with an 805-MHz pillbox cavity at the Fermilab MuCool Test Area has shown significant drop in accelerating field performance for the case of parallel electric and magnetic fields. It has been suggested that having the magnetic field perpendicular to the electric field should provide magnetic insulation and suppress breakdown. An 805-MHz Cu rectangular box cavity was built for testing with the fields perpendicular. It was mounted on an adjustable support to vary the angle between the rf electric and external magnetic field. We report on design and operation of the rectangular box cavity.
DESY, Hamburg
Building an accelerator facility brings together civil construction and mechanical engineering, two trades with very different working cultures, practices and tool sets: While construction sites are traditionally paper-based and 2D oriented, the accelerator and its infrastructure are completely modeled in 3D. At the European XFEL, methods and tools known from plant construction were introduced to civil construction to enable efficient collaboration of all trades. Integrated 3D models encompass design models of all technical subsystems. An electronic "XFEL room book" captures requirements and manages assignments of space, infrastructure and equipments in the buildings. The DESY Engineering Data Management System (EDMS) manages and links the information with additional documentation. Electronic workflows coordinate e.g. reviews and change management. 3D models, room book and documentation databases together constitute the so-called "Building Information Model" (BIM). The BIM addresses the entire building lifecycle and is a basis for later facility operation. The poster describes information management procedures, tools and experience in the civil construction of the European XFEL.
INFN/LNL, Legnaro (PD)
Universita' degli Studi di Milano e INFN, Milano
In a Malmberg'Penning trap like ELTRAP an electron beam can be stored or propagated in a space charge dominated condition, due to the low acceleration voltage used; in particular we can test the longitudinal expansion of the electron bunch with several diagnostics, including Thomson scattering. Pulsed electron beams produced by an external photocathode source in the 1'10 keV energy range and with 4 ns length have been measured also by two electrostatic diagnostic systems. A proper software is needed to compensate for the capacitance of the pickup electrodes. Rf can be applied to the sectored electrode to produce a plasma source or to excite or to detect rotational modes; in particular the use of a new 8 sector electrode will allow up to m=3 modes.
ESS Bilbao, Bilbao
Fundación TEKNIKER, Eibar (Gipuzkoa)
Bilbao, Faculty of Science and Technology, Bilbao
University of the Basque Country, Faculty of Science and Technology, Bilbao
STFC/RAL/ISIS, Chilton, Didcot, Oxon
ESS-Bilbao, Zamudio
Imperial College of Science and Technology, Department of Physics, London
Elytt Energy, Madrid
The rationale behind the Bilbao Accelerator Ion Source Test Stand (ITUR) project is to perform a comparison between different kinds of hydrogen ion sources using the same beam diagnostics setup. In particular, a direct comparison will be made in terms of the emittance characteristics of Penning-type sources such as those currently being used in ISIS (UK) and those of microwave type such as CEA-Saclay and INFN. The aim here pursued is to build an Ion Source Test Stand where virtually any type of source can be tested and, thus, compared to the results of other sources under the same gauge. It would then be possible to establish a common ground for effectively comparing different ion sources. The work here presented reports on the first simulations for the H-/H+ extraction system, as well the devices that conform the diagnostic vessel: Faraday Cup, Pepperpot and Retarding Potential Analyzer (RPA), among others.
STFC/RAL, Chilton, Didcot, Oxon
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
BNL, Upton, Long Island, New York
STFC/DL, Daresbury, Warrington, Cheshire
UBC & TRIUMF, Vancouver, British Columbia
Fermilab, Batavia
Brunel University, Middlesex
CERN, Geneva
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
TRIUMF, Vancouver
CEA, Gif-sur-Yvette
Imperial College of Science and Technology, Department of Physics, London
JAI, Oxford
The Electron Model for Many Applications (EMMA) will be the World's first non-scaling FFAG and is under construction at the STFC Daresbury Laboratory in the UK. Construction is due for completion in March 2010 and will be followed by commissioning with beam and a detailed experimental programme to study the functioning of this type of accelerator. This paper will give an overview of the motivation for the project and describe the EMMA design and hardware. The first results from commissioning will be presented in a separate paper.
Fermilab, Batavia
Phase space manipulation techniques within two degrees of freedom are foreseen to enhance the performances of next generation accelerators such as high-energy physics colliders and accelerator based light sources. At the Fermilab A0 photoinjector, a proof-of-principle experiment to demonstrate the exchange of the transverse and longitudinal emittances is ongoing. The emittance exchange beamline consists of a 3.9 GHz normal conducting deflecting mode cavity flanked by two doglegs. Electron bunches with charges of 250 pC and energy of 14.3 MeV are routinely sent through the exchanger. In this paper, we report our latest results on the demonstration of emittance exchange obtained with significantly improved beam diagnostics. We also compare our experimental results with a simple numerical model.
JLAB, Newport News, Virginia
The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab can be described as a series of concatenated beamlines. Methods used to measure the Twiss parameters in closed orbit machines are not applicable in such open ended systems. We are using properly selected sets of real orbits in the accelerator, as one would for numerical analysis. The evolution of these trajectories along the beamline models the behavior of a synthetic beam which deterministically supplements beam profile-based Twiss parameter measurements and optimizes the efficiency of beamline tuning. Examples will be presented alongside a description of the process.