Paper | Title | Other Keywords | Page |
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MOCL02 | Harmonically Resonant Cavity as a Bunch Length Monitor | cavity, electron, real-time, vacuum | 24 |
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Funding: US DOE DE-SC0009509 RF cavities have been designed and constructed that simultaneously and exclusively resonate many harmonic TMono modes. These modes are axially symmetric and have their electric field maximum along the cavities bore. A periodic beam passing through a harmonic cavities bore excites these modes whose superposition can be measured at the cavities antenna with a sampling oscilloscope. Processing the detected waveform with the harmonic cavities transfer function yields the Fourier series of the beam, and a near real-time, non-invasive measurement of the beams longitudinal bunch shape and duration. Experiments have been performed on the 130 kV injector at the Thomas Jefferson National Accelerator Facilities Continuous Electron Beam Accelerator Facility. The harmonic cavities sensitivity was near 1 mV/μA and measured beam bunches ranging in width from 45 to 150 picoseconds (FWHM). These measurements were in close agreement with measurements made using an invasive bunch measurement system as well as predictions by a particle tracking simulations. |
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Slides MOCL02 [11.027 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOCL02 | ||
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MOPG13 | MicroTCA.4 Based Optical Frontend Readout Electronics and its Applications | feedback, electronics, operation, electron | 67 |
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In the paper the MicroTCA.4 based optical frontend readout (OFR) electronics and its applications for beam arrival time monitor (BAM) and fast beam based feed-back (BBF) is presented. The idea is to have a possibility to monitor the modulation density of the optical laser pulses by the electron bunches and apply this information for the BBF. The OFR composed of double width fast mezzanine card (FMC) and advanced mezzanine card (AMC) based FMC carrier. The FMC module consists of three optical channel inputs (data and clock), two optical channel outputs (beam arrival time), 250 MSPS ADCs, clock generator module (CGM) with integrated 2.8 GHz voltage control oscillator (VCO). The optical signals are detected with 800 MHz InGaAs photodiodes, conditioned using 2 GHz current-feedback amplifiers, filtered by 3.3 GHz differential amplifiers and next direct sampled with 16-bit 900 MHz of analog bandwidth ADCs. The CGM is used to provide clock outputs for the ADCs and for the FMC carrier with additive output jitter of less than 300 fs rms. The BAM application has been implemented using Virtex 5 FPGA and measured with its performance at Free Electron LASer in Hamburg (FLASH) facility. | |||
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Poster MOPG13 [3.991 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG13 | ||
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MOPG28 | The Brookhaven Linac Isotope Production (BLIP) Facility Raster Scanning System First Year Operation with Beam | target, linac, instrumentation, isotope-production | 105 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Dept. of Energy Brookhaven National Laboratory's BLIP facility produces radioisotopes for the nuclear medicine community and industry, and performs research to develop new radioisotopes desired by nuclear medicine investigators. A raster scanning system was recently completed in December 2015 and fully commissioned in January 2016 to provide improved beam distribution on the targets, allow higher beam intensities, and ultimately increase production yield of the isotopes. The project included the installation of horizontal and vertical dipole magnets driven at 5 kHz with 90 deg phase separation to produce a circular beam raster pattern, a beam interlock system, and several instrumentation devices including multi-wire profile monitors, a laser profile monitor, beam current transformers and a beam position monitor. The first year operational experiences will be presented. |
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Poster MOPG28 [39.944 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG28 | ||
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MOPG35 | Single Pulse Sub-Picocoulomb Charge Measured by a Turbo-ICT in a Laser Plasma Accelerator | background, target, plasma, electron | 119 |
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Funding: The work by the BELLA Center scientists and staff was supported by Office of Science, Office of HEP, US DOE under Contract DE-AC02-05CH11231 and the National Science Foundation. Experiments at the Berkeley Lab Laser Accelerator (BELLA) verified that the Turbo-ICT allows high resolution charge measurements even in the presence of strong background signals. For comparison, a Turbo-ICT and a conventional ICT were installed on the BELLA petawatt beamline, both sharing the same vacuum flanges. We report on measurements performed using a gas-jet and a capillary-discharge based laser plasma accelerator. In both setups the Turbo-ICT was able to resolve sub-picocoulomb charges. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG35 | ||
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MOPG51 | Electron Beam Longitudinal Diagnostic With Sub-Femtosecond Resolution | undulator, electron, diagnostics, cavity | 173 |
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Ultra-short, high brightness electron beams, with applications to next generation light sources or advanced accelerators, require enhanced resolution of the longitudinal bunch properties to study effects such as the micro-bunching instability. In this paper, we describe a diagnostic that has the promise to achieve sub-femtosecond longitudinal resolution. The diagnostic employs a laser-electron beam interaction in an undulator magnet in tandem with a RF bunch deflecting cavity to impose a angular-longitudinal coordinate correlation on the bunch which is resolvable with standard optical systems. The fundamental underlying concepts of the diagnostic have been tested experimentally at the Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) with the high-brightness electron beam and >100GW IR laser operating in the TEM10 mode. The results include a systematic study of the effects of this laser mode, and energy, on the beam angular projection. Initial runs from the x-band deflecting cavity will also be presented here. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG51 | ||
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MOPG52 | Simulation of THz Streak Camera Performance for Femtosecond FEL Pulse Length Measurement | FEL, electron, simulation, photon | 176 |
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Measurement of the temporal duration of FEL pulses is important both for the operators to monitor the performance of the machine and the users performing pump-probe measurements with FEL beam. The light-field streak camera is a promising methods for the photon pulse length measurement that uses the electric field of an IR/THz laser to streak the photoelectrons*. This contribution presents a simulation of the performance of a streak camera using a single-cycle THz pulse**. The simulation recreates the photoionization process and generates electron spectra in presence of the THz field and without it. Using these spectra the photon pulse lengths are calculated and compared to the initial values. Most of the parameters used in the simulation are chosen based on experiments performed earlier.*** This contribution presents the simulation method and the obtained results. It validates the pulse length calculation analysis method and estimates the expected measurement accuracy and precision for the THz streak camera measurement technique. The simulations were done for different FEL pulse lengths ranging from about 1 fs to 40 fs both in soft and hard X-ray range.
*J. Itatani et al, PRL 88,2002 *U. Fruhling et al, N. Phot. 3,2009 **I. Gorgisyan et al, JSR 3,2016 ***P. N. Juranic et al, Opt. Exp. 22,2014 ***P. N. Juranic et al, J. Inst. 9,2014 |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG52 | ||
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MOPG54 | Laser-Based Beam Diagnostics for Accelerators and Light Sources | network, electron, diagnostics, emittance | 183 |
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Funding: This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191. The Laser Applications at Accelerators network (LA≥NET) was selected for funding within the European Union's 7th Framework Programme. During its 4 year duration the project has successfully trained 19 Fellows and organized numerous events that were open to the wider laser and accelerator communities. The network linked research into lasers and accelerators to develop advanced particle sources, new accelerating schemes, and in particular beyond state-of-the-art beam diagnostics. This contribution summarizes the research results in laser-based beam diagnostics for accelerators and light sources. It discusses the achievable resolution of laser-based velocimeters to measure the velocity of particle beams, the resolution limits of bunch shape measurements using electro-optical crystals, position resolution of laser wire scanners, and limits in energy measurements using Compton backscattering at synchrotron light sources. Finally, it also provides a summary of past and future events organized by the network and shows how an interdisciplinary research program can provide comprehensive training to a cohort of early career researchers. |
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Poster MOPG54 [0.698 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG54 | ||
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MOPG57 | Temperature and Humidity Drift Characterization of Passive RF Components for a Two-Tone Calibration Method | detector, injection, radio-frequency, hardware | 194 |
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Femtosecond-level synchronization is required for various systems in modern accelerators especially in fourth generation light sources. In those high precision synchronization systems the phase detection accuracy is crucial. However, synchronization to a low noise electrical source is corrupted by a phase detection error originating in the electrical components and connections due to thermal and humidity-related drifts. In future, we plan to implement calibration methods to mitigate these drifts. Those methods require a calibration signal injection, called second tone, into the system. Intrinsically, the injection circuit remains uncalibrated therefore it needs to be drift-free. We performed drift characterization of a set of RF components, which could serve for implementation of a signal injection circuit, namely selected types of couplers and splitters. We describe the measurement setup and discuss the challenges associated with this kind of measurement. Finally, we provide a qualitative and quantitative evaluation of the measurements results. | |||
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Poster MOPG57 [2.823 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG57 | ||
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MOPG60 | Development, Calibration and Application of New-Generation Dissectors With Picosecond Temporal Resolution | electron, operation, radiation, synchrotron | 205 |
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A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP SB RAS is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations. LI-602 dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the GPI Photoelectronics Department. The results of the measurements of instrument function of the new dissector based on PIF-01/S1, which were carried out in the static mode, showed that temporal resolution of the dissector can be better than 3-4 ps (FWHM). The results of temporal resolution calibration of the new-generation picosecond dissector, carried out at the specialized set-up based on a femtosecond Ti:sapphire laser, and recent results of longitudinal beam profile measurements at BINP accelerators are given in this work. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG60 | ||
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MOPG72 | Diagnostic Test-Beam-Line for the Injector of MESA | emittance, cathode, electron, diagnostics | 244 |
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Funding: Work supported by the German Science Foundation (DFG) under the Cluster of Excellence PRISMA For the planed Mainzer Energy-recovering Superconducting Accelerator (MESA) at the Johannes Gutenberg-University in Mainz a diagnostic test-beam-line has been build up. The beam-line comprises three analyzing stations to investigate space charge caused transverse emittance growth of an 100 keV electron beam. To create the electron bunches two different rf syncronized laser diodes (405 nm & 520 nm) are used. Furthermore, a circular deflecting cavity allows to measure the longitudinal bunch intensity profile. The components and the latest results will be described and an outlook towards further applications will be given. |
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Poster MOPG72 [13.456 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG72 | ||
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TUBL03 | Synchronous Laser-Microwave Network for Attosecond-Resolution Photon Science | timing, network, detector, polarization | 286 |
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Funding: This work was supported by the Center for Free-Electron Laser Science at Deutsches Elektronen-Synchrotron, a research center of the Helmholtz Association in Germany. Next-generation photon-science facilities such as X-ray free-electron lasers (X-FELs)* and intense-laser beamline centers** are emerging world-wide with the goal of generating sub-fs X-ray pulses with unprecedented brightness to capture ultrafast chemical and physical phenomena with sub-atomic spatiotemporal resolution. The only obstacle preventing this long-standing scientific dream to come true is a high- precision timing distribution system*** synchronizing various microwave and optical sub-sources across multi-km distances which is required for seeded X-FELs and attosecond pump-probe experiments. Here, we present, for the first time, a synchronous laser-microwave network that will enable attosecond precision photon science facilities. By developing new ultrafast metrological timing devices and carefully balancing fiber nonlinearities and fundamental noise contributions, we have achieved timing stabilization of a 4.7 km fiber network with 580 attosecond precision over 52 hours. Furthermore, we have realized a complete laser-microwave network incorporating two mode-locked lasers and one microwave source with total 950 attosecond jitter integrated from 1 microsecond to 18 hours. *J. Stohr, LCLS-II Conceptual Design Report. No. SLAC-R-978. (SLAC, 2011). **G. Mourou, T. Tajima, Optics & Photonics News 22, 47 (2011). ***J. Kim, et al., Nat. Photonics 2(12), 733-736 (2008). |
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Slides TUBL03 [11.692 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUBL03 | ||
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TUBL04 | Electro-Optical Methods for Multipurpose Diagnostics | electron, plasma, acceleration, target | 290 |
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Electro-optic sampling (EOS) based temporal diagnostics allows to precisely measure the temporal profile of electron bunches with resolution of about 50 fs in a non-destructive and single-shot way. At SPARC_LAB we adopted the EOS in very different experimental fields. We measured for the first time the longitudinal profile of a train of multiple bunches at THz repetition rate, as the one required for resonant Plasma Wakefield Acceleration (PWFA) in a single-shot and non-intercepting way. By means of the EOS we demonstrated a new hybrid compression scheme that is able to provide ultra-short bunches (<90 fs) with ultra-low (<20 fs) timing-jitter relative to the EOS laser system. Furthermore, we recently developed an EOS system in order to provide temporal and energy measurements in a very noisy and harsh environment: electron beams ejected by the interaction of high-intensity (hundreds TW class) ultra-short (35fs) laser pulses with solid targets by means of the so-called Target Normal Sheath Acceleration (TNSA) method. | |||
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Slides TUBL04 [2.183 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUBL04 | ||
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TUPG31 | The Alignment of Convergent Beamlines at a New Triple Ion Beam Facility | ion, target, experiment, alignment | 403 |
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The Michigan Ion Beam Laboratory (MIBL) at the University of Michigan in Ann Arbor Michigan, USA, has recently upgraded its capabilities from a two accelerator to a three accelerator operation mode. The laboratory, equipped with a 3 MV Tandem, a 400 kV Ion Implanter and a 1.7 MV Tandem has also increased the number of available beamlines from three to seven with two more in the planning stages. The MIBL staff had to overcome multiple challenges during the physical alignment process of the accelerators, beamlines and experimental end-stages. Not only the position of the accelerators changed, but the target chambers were moved into a different room behind a 1 m thick concrete wall. At the same time, one beamline from each accelerator had to converge and connect to a single chamber at a precise angle. This setup allows researchers to conduct simultaneous dual and triple ion beam experiments. This work presents the details of building this new setup, with focus on the alignment process. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG31 | ||
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TUPG53 | Bunch Arrival-Time Monitoring for Laser Particle Accelerators and Thomson Scattering X-Ray Sources | electron, timing, pick-up, detector | 468 |
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The ELBE center of high power radiation sources at Helmholtz-Zentrum Dresden-Rossendorf combines a superconducting CW linear accelerator with Terawatt- and Petawatt-level laser sources. Key experiments rely on precise timing and synchronization between the different radiation pulses. An online single shot monitoring system has been set up in order to measure the timing between the high-power Ti:Sa laser DRACO and electron bunches generated by the conventional SRF accelerator. This turnkey timing system is suitable for timing control of Thomson scattering X-ray sources and external injection of electron bunches into a laser wakefield accelerator. It uses a broadband RF pickup to acquire a probe of the particle bunch's electric field and modulates a fraction of the high power laser pulse in a fast electro-optical modulator. The amplitude modulation gives a direct measure for the timing between both beams. Using this setup a resolution of <200 fs RMS has been demonstrated. The contribution will show the prototype, first measurement results and will discuss future modification in order to improve the resolution of the system. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG53 | ||
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TUPG56 | Design of a Time-resolved Electron Diagnostics Using THz Fields Excited in a Split Ring Resonator at FLUTE | electron, diagnostics, simulation, gun | 475 |
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Time-resolved electron diagnostics with ultra-high temporal resolution is increasingly required by the state-of-the-art accelerators. Strong terahertz (THz) fields, excited in a split ring resonator (SRR), have been recently proposed to streak electron bunches for their temporal characterisation. Thanks to the high amplitude and frequency of the THz field, temporal resolution down to the sub-femtosecond range can be expected. We are planning a proof-of-principle experiment of the SRR time-resolved diagnostics at the accelerator test-facility FLUTE (Ferninfrarot Linac und Test Experiment) at the Karlsruhe Institute of Technology. The design of the experimental chamber has been finished and integrated into the design layout of the FLUTE accelerator. Beam dynamics simulations have been conducted to investigate and optimise the performance of the SRR diagnostics. In this paper, we present the design layout of the experimental setup and discuss the simulation results for the optimised parameters of the accelerator and the SRR structure. | |||
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Poster TUPG56 [6.961 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG56 | ||
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TUPG58 | Measurement of Femtosecond Electron Beam Based on Frequency and Time Domain Schemes | electron, linac, gun, radiation | 483 |
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Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer* is one of candidates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA)** based on time-domain analysis has been investigated. The PCA with enhanced radial polarization characteristics enabled time-domain analysis for electron beam because of radially polarized THz pulse of CTR. In this presentation, measurement of femtosecond electron beam with 35 MeV energy and < 1 nC from a photocathode based linac will be reported. Frequency- and time- domain analysis of THz pulse of CTR by combining the interferometer and PCA will be carried out.
* I. Nozawa, K. Kan et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014). ** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013). |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG58 | ||
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TUPG61 | Stable Transmission of RF Signals and Timing Events With Accuracy at Femtoseconds | timing, electron, feedback, controls | 491 |
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Funding: Supported by the National Natural Science Foundation of China (No. 11305246) and the Youth Innovation Promotion Association CAS (No. 2016238). We present a new design of femtosecond timing system. In the system, RF signal and timing events are transmitted synchronously in one single optical fiber with very high accuracy. Based on the theory of Michelson's interferometer, phase drift is detected with accuracy at femtoseconds. And phase compensation is accomplished in transmitter with two approaches afterwards. Moreover, the traditional event timing system is integrated into the new system to further reduce the jitter of timing triggers. The system could be applied in synchrotron light sources, free electron lasers and colliders, where distribution of highly stable timing information is required. The physics design, simulation analysis and preliminary results are demonstrated in the paper. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG61 | ||
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TUPG77 | Experimental Results of a Compact Laserwire System for Non-Invasive H− Beam Profile Measurements at CERN's Linac4 | linac, detector, electron, optics | 544 |
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Funding: Support from UK STFC, grant ST/N001753/1. A non-invasive laserwire system is being developed for quasi-continuous monitoring of the transverse profile and emittance of the final 160 MeV beam at CERN's LINAC4. As part of these developments, a compact laser-based profile monitor was recently tested during LINAC4 commissioning at beam energies of 50 MeV, 80 MeV and 107 MeV. A laser with a tunable pulse width (1-300 ns) and ~200 W peak power in a surface hutch delivers light via a 75 m LMA transport fibre to the accelerator. Automated scanning optics deliver a free space <150 micron width laserwire to the interaction chamber, where a transverse slice of the hydrogen ion beam is neutralised via photo-detachment. The liberated electrons are deflected by a low field dipole and captured by a sCVD diamond detector, that can be scanned in synchronisation with the laserwire position. The laserwire profile of the LINAC4 beam has been measured at all commissioning energies and is found in very good agreement with interpolated profiles from conventional SEM-grid and wire scanner measurements, positioned up and downstream of the laserwire setup. Improvements based on these prototype tests for the design of the final system are presented. |
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Poster TUPG77 [3.695 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG77 | ||
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WECL01 | Longitudinal Phase Space Diagnostics for Ultrashort Bunches With a Plasma Deflector | plasma, electron, wakefield, injection | 597 |
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We present with simulations a new method to diagnose the longitudinal phase space of ultrashort electron bunches. It harnesses the strong transverse fields of laser-driven wakefields to streak an electron bunch that is injected off-axis with respect to the driver laser. Owed to the short plasma wavelength and the high field amplitude present in a plasma wakefield, a temporal resolution around or below the femtosecond can be achieved with a plasma length of a few millimeters. We will explore the limitations on the time resolution, the calibration, and the influence of error sources such as beam loading and jitters. Amongst the possible applications are experiments aiming at external injection into laser-driven wakefields, or the diagnostics of laser-plasma accelerated beams. | |||
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Slides WECL01 [5.430 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WECL01 | ||
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WEPG09 | Development of a Prototype Electro-Optic Beam Position Monitor at the CERN SPS | pick-up, polarization, proton, optics | 634 |
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Funding: Project funded by UK STFC grant, ST/N001583/1 A novel electro-optic beam position monitor capable of rapidly (<50ps) monitoring transverse intra-bunch perturbations is under development for the HL-LHC project. The EO-BPM relies on the fast optical response of two pairs of electro-optic crystals, whose birefringence is modified by the passing electric field of a 1ns proton bunch. Analytic models of the electric field are compared with electromagnetic simulations. A preliminary opto-mechanical design of the EO-BPM was manufactured and installed at the CERN SPS in 2016. The prototype is equipped with two pairs of 5mm cubic LiNbO3 crystals, mounted in the horizontal and vertical planes. A polarized CW 780nm laser in the counting room transmits light via 160m of PM fibre to the SPS, where delivery optics directs light through a pair of crystals in the accelerator vacuum. The input polarization state to the crystal can be remotely controlled. The modulated light after the crystal is analyzed, fibre-coupled and recorded by a fast photodetector in the counting room. Following the recent installation, we present the detailed setup and report the latest status on commissioning the device in-situ at the CERN SPS. |
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Poster WEPG09 [8.441 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG09 | ||
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WEPG19 | Conceptual Design of LEReC Fast Machine Protection System | gun, electron, vacuum, dipole | 665 |
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The low energy RHIC Electron Cooling (LEReC) accelerator will be running with electron beams of up to 110 kW power with CW operation at 704MHz. Although electron energies are relatively low (< 2.6MeV), at several locations along the LEReC beamline, where the electron beam has small (about 250 um RMS radius) design size, it can potentially hit the vacuum chamber at a normal incident angle. The accelerator must be protected against such a catastrophic scenario by a dedicated machine protection system (MPS). Such an MPS shall be capable of interrupting the beam within a few tens of microseconds. In this paper we describe the current conceptual design of the LEReC MPS. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG19 | ||
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WEPG32 | First Heating with the European XFEL Laser Heater | electron, undulator, interaction-region, resonance | 694 |
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Funding: DESY and Swedish Research council The European XFEL is a 3.4 km long free-electron laser (FEL) which will deliver radiation in the wavelength regime of 0.05 to 4.7 nm. To avoid problems with longitudinal microbunching instabilities a laser heater is implemented. It heats up the electron bunches which will improve the overall brightness level of the FEL. I report the commissioning steps undertaken and the first recorded heating outputs observed in the injector section. |
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Poster WEPG32 [2.322 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG32 | ||
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WEPG44 | Longitudinal Phase Space Measurement at the ELI-NP Compton Gamma Source | linac, electron, brightness, dipole | 732 |
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Virtual bunch length measurement can be carried out by means of ELEGANT code for tracking the bunch particles from RF deflector to the screen. The technique relies on the correlation between the bunch longitudinal coordinate and transverse coordinates induced through a RF deflector. Therefore, the bunch length measurement can be carried out measuring the vertical spot size at the screen, placed after the RF deflector. The deflecting voltage amplitude affects the resolution. Adding a dispersive element, e.g. a magnetic dipole between RF deflector and the screen, the full longitudinal phase space can be measured. In this paper, we discuss some issues relevant for the electron linac of the Compton source at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP). | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG44 | ||
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WEPG45 | Present Status of the Laser Charge Exchange Test Using the 3-MeV Linac in J-PARC | proton, linac, experiment, rfq | 736 |
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The accelerator-driven system (ADS) is discussed as one of the efficient device to transmute long-lived nuclides. For the efficient transmutation of the minor actinide (MA), precise prediction of neutronic performance of ADS is indispensable. The Transmutation Physics Experimental Facility (TEF-P) aimed at obtaining experimental data for the accuracy improvement of neutronics evaluation of MA-loaded ADS. The critical assembly installed in TEF-P operates below 500 watt to prevent the excessive radio activation of assembly. For the separation of low power beam from J-PARC intense proton accelerator, the meticulous low power beam extraction method from high power proton beam is required. The laser charge exchange method (LCE) is originally developed to measure the proton beam profile and can be applied to the beam separation device for TEF-P. The LCE device consists of bright YAG-laser and laser transport system with beam position controllers. We performed the stability tests for laser power and position of exposure by no proton beam condition. The further LCE tests using negative 3-MeV proton linac in J-PARC will be conducted. In this paper, present status of LCE tests is presented. | |||
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Poster WEPG45 [16.240 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG45 | ||
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WEPG46 | KALYPSO: A Mfps Linear Array Detector for Visible to NIR Radiation | detector, diagnostics, electron, real-time | 740 |
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Funding: This work is partially funded by the BMBF contract number: 05K16VKA. The acquisition rate of commercially available line array detectors is a bottleneck for beam diagnostics at high-repetition rate machines like synchrotron lightsources or FELs with a quasi-continuous or macro-pulse operation. In order to remove this bottleneck we have developed KALYPSO, an ultra-fast linear array detector operating at a frame-rate of up to 2.7 Mfps. The KALYPSO detector mounts InGaAs or Si linear array sensors to measure radiation in the near-infrared or visible spectrum. The FPGA-based read-out card can be connected to an external data acquisition system through a high-performance PCI-Express 3.0 data-link, allowing continuous data taking and real-time data analysis. The detector is fully synchronized with the timing system of the accelerator and other diagnostic instruments. The detector is currently installed at several accelerators: ANKA, the European XFEL and TELBE. We present the detector and the results obtained with Electro-Optical Spectral Decoding (EOSD) setups. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG46 | ||
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WEPG47 | Progress on the PITZ TDS | emittance, electron, simulation, space-charge | 744 |
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A transverse deflecting system (TDS) is under commissioning at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). The structure was designed and manufactured by the Institute for Nuclear Research (INR RAS, Moscow, Russia) as prototype for the TDS in the injector part of the European XFEL. Last year the deflection voltage was limited for safety reasons, but after thorough investigations of the waveguide system we are now able to operate the cavity close to design specifications. The PITZ TDS streaks the electron beam vertically, allowing measurements of the longitudinal bunch profile, and, in combination with a subsequent horizontal bending magnet, also of the longitudinal phase space and slice energy spread. Furthermore, several quadrupole magnets and screen stations can be employed for slice emittance measurements using the TDS. This paper describes the progress in commissioning of the hardware, measurement techniques and simulations, and outlines the prospects of reliable slice emittance measurements at 20 MeV/c, where space charge forces complicate the determination of transfer matrices. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG47 | ||
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WEPG48 | A THz Driven Transverse Deflector for Femtosecond Longitudinal Profile Diagnostics | electron, vacuum, diagnostics, acceleration | 748 |
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Progress towards a THz-driven transverse deflecting longitudinal profile diagnostic is presented. The deflector is driven with sub-picosecond quasi-single cycle THz fields generated by non-linear optical rectification. To utilize the large deflection field strength of the source for longitudinal diagnostics it is necessary to maintain the single-cycle field profile of the THz pulse throughout the interaction with the relativistic beam. Our scheme allows for the octave spanning bandwidth of the single-cycle pulses to propagate without dispersion at subluminal velocities matched to co-propagating relativistic electrons, by passing the pulse distortion and group-carrier walk-off limitations of dielectric loaded waveguide structure. The phase velocity is readily tuneable, both above and below the speed of light in a vacuum, and single-cycle propagation of deflecting fields at velocities down to 0.77c have been demonstrated. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG48 | ||
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WEPG49 | A High Resolution Single-Shot Longitudinal Profile Diagnostic Using Electro-Optic Transposition | diagnostics, electron, optics, real-time | 752 |
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Funding: This work was funded by CERN through contract KE1866/DG/CLIC and carried out at STFC Daresbury Laboratory. Electro-Optic Transposition (EOT) is the basis for an improved longitudinal bunch profile diagnostic we are developing in ASTeC as part of the CLIC UK research program. The scheme consists of transposing the Cou-lomb field profile of an electron bunch into the intensity envelope of an optical pulse via the mixing processes that occur between a CW laser probe and Coulomb field in an electro-optic material. This transposed optical pulse can then be amplified and characterised using robust laser techniques ' in this case chirped pulse optical parametric amplification and frequency resolved optical gating, allowing the Coulomb field to be recovered. EOT is an improvement over existing techniques in terms of the achievable resolution which is limited by the EO material response itself, reduced complexity of the laser system required since nanosecond rather than femtosecond lasers are used, and insensitivity of the system to bunch-laser arrival time jitter due to using a nanosecond long probe. We present results showing the retrieval of a THz pulse (Coulomb field stand-in) which confirms the principle behind the EOT system. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG49 | ||
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WEPG52 | Laser Arrival Time Measurement and Correction for the SwissFEL Lasers | timing, gun, FEL, experiment | 763 |
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SwissFEL will ultimately produce sub-fs X-ray pulses. Both the photo-injector laser and the pump lasers used for the experimental end stations therefore have tight requirements for relative arrival time to the machine and the X-rays. The gun laser oscillator delivers excellent jitter performance at ~20fs integrated from 10Hz-10MHz. The Yb:CaF2 regenerative amplifier, with an over 1km total propagation path, calls for active control of the laser arrival time. This is achieved by balanced cross-correlation against the oscillator pulses and a translation stage before amplification. The experimental laser, based on Ti:sapphire laser technology will use a spectrally resolved cross-correlator to determine relative jitter between the optical reference and the laser, with fs resolution. To be able to perform fs resolution pump-probe measurements the laser has to be timed with the X-rays with <10fs accuracy. These systems will be integrated into the machine timing and complemented by electron bunch and X-ray timing tools. Here we present the overall concept and the first results obtained on the existing laser systems. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG52 | ||
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WEPG53 | Unambiguous Electromagnetic Pulse Retrieval Through Frequency Mixing Interference in Frequency Resolved Optical Gating | radiation, electron, diagnostics, framework | 767 |
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We demonstrate a method for full and unambiguous temporal characterization of few-cycle electromagnetic pulses, including retrieval of the carrier envelope phase (CEP), in which the interference between non-linear frequency mixing components is spectrally resolved using Frequency Resolved Optical Gating (FROG). We term this process Real-Domain FROG (ReD-FROG) and demonstrate its capabilities through the complete measurement of the temporal profile of a single-cycle THz pulse. When applied at THz frequencies ReD-FROG overcomes the bandwidth limitations relating probe and test pulses in Electro-Optic (EO) sampling. The approach can however be extended generally to any frequency range and we provide a conceptual demonstration of the CEP retrieval of few-cycle optical field. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG53 | ||
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WEPG55 | Synchronization of ps Electron Bunches and fs Laser Pulses Using a Plasmonics-Enhanced Large-Area Photoconductive Detector | electron, detector, quadrupole, vacuum | 774 |
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Temporal synchronization between short relativistic electron bunches and laser pulses at the ps and sub-ps level is required for accelerator applications like inverse Compton light sources. Photoconductive antennas with THz and sub-THz bandwidth which are gated by fs lasers provide this level of timing resolution. This paper describes the operating principals of the diagnostic along with bench-top experimental results with recently developed plasmonics-enhanced large-area devices. A vacuum chamber with robust electronic noise reduction has been designed for upcoming beam-based experiments. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG55 | ||
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WEPG67 | Non-Invasive Beam Profile Measurement for High Intensity Electron Beams | electron, photon, background, detector | 803 |
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Beam profile measurements of high intensity electron beams below 10 MeV, e.g. in energy recovery linacs or magnetized high energy electron coolers, have to fulfill special demands. Commonly used diagnostic tools like synchrotron radiation and scintillation screens are ineffective or not able to withstand the beam power without being damaged. Non-invasive methods with comparable resolution are needed. Hence, a beam profile measurement system based on beam-induced fluorescence (BIF) was built. This quite simple system images the light generated by the interaction of the beam with the residual gas onto a PMT. A more elaborated system, the Thomson Laser Scanner (TLS) - the non-relativistic version of the Laser Wire Scanner - is proposed as a method for non-invasive measurement of all phase space components, especially in the injector and merger parts of an ERL. Since this measurement suffers from low count rates, special attention has to be given to the background. Beam profile measurements with the BIF system will be presented as well as a comparison with YAG screen measurements. The recent status of the TLS system will be presented. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG67 | ||
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THAL01 | PALM Concepts and Considerations | electron, FEL, photon, free-electron-laser | 848 |
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The Photon Arrival and Length Monitor (PALM), a THz streak camera device developed by PSI for non-destructive hard x-ray measurements of photon pulse length and arrival time versus a pump laser*, was brought to the SACLA XFEL** in Japan in a cross-calibration temporal diagnostics campaign after an initial experiment where only the PALM was being used***. The device was used with 9 keV pink beam and a 9.0 and 8.8 keV two-color mode, successfully measuring the arrival time and pulse lengths for several different FEL operating conditions. The device has shown itself to be very robust and transparent to the FEL beam, with temporal characterization accuracies of 15 fs or better. SwissFEL will employ two such devices at the end stations for use by both operators and experimenters to improve the operation of the FEL and to better interpret experimental data. This report presents the PALM and its uses and capabilities, and discusses the results from the SACLA cross-calibration experiments.
* P. N. Juranic et. al, Journal of Instrumentation (2014) 9. ** T. Ishikawa et. al., Nature Photonics (2012) 6(8). *** P. N. Juranic et. al., Optics Express (2014) 22. |
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Slides THAL01 [85.575 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-THAL01 | ||
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THAL03 | Multi-Laser-Wire Diagnostic for the Beam Profile Measurement of a Negative Hydrogen Ion Beam in the J-PARC LINAC | linac, electron, cavity, ion | 856 |
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In the J-PARC linac, the negative hydrogen ion beam is acceralated to be 400 MeV. Repitition rate will be increased to be from 25 Hz to 50 Hz. The half of 400 MeV beams are injected to the downstream scynchlotoron (RCS) and the other half will be transported to the planned experimental laboratory of the accelerator driven transmutation facility. One of the important issues for the high-current and high-brilliance accelerators is to understand the beam dynamics. The wire scanner monitor is reliably operated in many accelerator facilities around the world. Because the heat loading on a wire is getting increaced in high-current beam tuning, we focused to use a laser wire system. Ionization potential of the negative hydrogen ion is 0.75 eV and one electron is easily detached by a laser beam whose wavelength is adjusted by the Doppler-shift to a large cross-section point. In addition, we propose to use a new multi-laser-wire system. In the new system, we use a pair of concave millors with different diameters to make multi-paths of laser beam, and the beam waists of the laser paths are aligned in principle. In the paper, we propose the multi-laser-wire system and its application. | |||
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Slides THAL03 [1.861 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-THAL03 | ||
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