IBIC2016 - List of Keywords (gun)

Paper	Title	Other Keywords	Page
MOBL02	First Experience with the Standard Diagnostics at the European XFEL Injector	diagnostics, operation, electron, electronics	14
	D. Lipka, A. Affeldt, A. Awwad, N. Baboi, B. Barret, B. Beutner, F. Brinker, W. Decking, A. Delfs, M. Drewitsch, O. Frank, C. Gerth, V. Gharibyan, O. Hensler, M. Hoeptner, M. Holz, K.K. Knaack, F. Krivan, I. Krouptchenkov, J. Kruse, G. Kube, B. Lemcke, T. Lensch, J. Liebing, T. Limberg, B. Lorbeer, J. Lund-Nielsen, S.M. Meykopff, B. Michalek, J. Neugebauer, Re. Neumann, Ru. Neumann, D. Nölle, M. Pelzer, G. Petrosyan, Z. Pisarov, P. Pototzki, G. Priebe, K.R. Rehlich, D. Renner, V. Rybnikov, G. Schlesselmann, F. Schmidt-Föhre, M. Scholz, L. Shi, P.A. Smirnov, H. Sokolinski, C. Stechmann, M. Steckel, R. Susen, H. Tiessen, S. Vilcins, T. Wamsat, N. Wentowski, M. Werner, Ch. Wiebers, J. Wilgen, K. Wittenburg, R. Zahn, A. Ziegler DESY, Hamburg, Germany R. Baldinger, R. Ditter, B. Keil, W. Koprek, R. Kramert, G. Marinkovic, M. Roggli, M. Stadler, D.M. Treyer PSI, Villigen PSI, Switzerland A. Ignatenko DESY Zeuthen, Zeuthen, Germany A. Kaukher XFEL. EU, Hamburg, Germany O. Napoly, C. Simon CEA/DSM/IRFU, France
	The injector of the European XFEL is in operation since December 2015. It includes, beside the gun and the accelerating section, containing 1.3 and a 3.9 GHz accelerating module, a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems are installed in the injector. Therefore the operation of the injector is served to validate and prove the diagnostics characteristics for the complete European XFEL. Most of the standard diagnostics has been available for the start of beam operation and showed the evidence of first beam along the beam line. In the following months the diagnostics has been optimized and used for improvements of beam quality. First operational experiences and results from the standard beam diagnostics in the injector of the European XFEL will be reported in this contribution.
	Slides MOBL02 [5.844 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOBL02
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MOPG38	Characterization and Simulations of Electron Beams Produced From Linac-Based Intense THz Radiation Source	electron, linac, cathode, radiation	131
	N. Chaisueb, S. Rimjaem, J. Saisut Chiang Mai University, Chiang Mai, Thailand N. Kangrang Chiang Mai University, PBP Research Facility, Chiang Mai, Thailand
	Electron beams with a maximum energy of 2.5 MeV and a macropulse current of 1 A are produced from a thermionic RF-gun of the linear accelerator system at Chiang Mai University, Thailand. An RF rectangular waveguide and a side coupling cavity of the RF gun introduce asymmetric field distribution inside the gun cavities. To investigate the effect of the asymmetric field distribution on electron beam production and acceleration, measurements and simulations of the electron beam properties were performed. In this study we use well calibrated current transformers, alpha magnet energy slits, and a Michelson interferometer to measure the electron pulse current, the beam energy, and the bunch length, respectively. This paper presents the measurement data of the electron beam properties at various location along the beam transport line and compares the results with the beam dynamic simulations by using the particle tracking program ELEGANT. Moreover, the RF field feature and the cathode power were optimized in order to achieve the high qualities of the electron beam produced from the RF gun. This result implies and correlates to the electron back-bombardment effect inside the gun cavities. * This work has been supported by the Thailand Center of Excellence in Physics, Faculty of science, Chiang Mai University, and the Science Achievement Scholarship of Thailand (SAST).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG38
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MOPG53	Electron Beam Probe Diagnostic for BESSY II Storage Ring	electron, diagnostics, synchrotron, simulation	179
	D. Malyutin, A.N. Matveenko HZB, Berlin, Germany
	A low energy electron beam can be used to characterize the high energy ultra-relativistic bunches. This technique allows one to obtain the bunch transverse profiles as well as the bunch length within a non-destructive single shot measurement. In this paper the bunch length measurement technique based on the interaction of the low energy electron beam with an ultra-relativistic bunch is described. Results of numerical simulations of measurements related to BESSY II are presented. A possible setup of such diagnostic system for BESSY II and in future for BESSY VSR is proposed.
	Poster MOPG53 [0.868 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG53
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TUPG35	LEReC Instrumentation Design & Construction	electron, ion, injection, emittance	417
	T.A. Miller, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, J.M. Fite, D.M. Gassner, R.L. Hulsart, D. Kayran, J. Kewisch, C. Liu, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, P. Oddo, M.C. Paniccia, I. Pinayev, S. Seletskiy, K.S. Smith, Z. Sorrell, P. Thieberger, J.E. Tuozzolo, D. Weiss, A. Zaltsman BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy RHIC will be run at low ion beam center-of-mass energies of 7.7 - 20 GeV/nucleon, much lower than the typical operations at 100 GeV/nucleon. The primary motivation is to explore the existence and location of the critical point on the QCD phase diagram. An electron accelerator is being constructed to provide Low Energy RHIC electron Cooling (LEReC) to cool both the blue & yellow RHIC ion beams by co-propagating a 10 - 50 mA electron beam of 1.6 - 2.6 MeV. This cooling facility will include a 400 keV DC gun, SRF booster cavity and a beam transport with multiple phase adjusting RF cavities to bring the beam to one ring to allow electron-ion co-propagation for ~21 m, then through a 180° U-turn electron transport so that the same electron beam can similarly cool the other counter-rotating ion beam, and finally to a beam dump. The injector commissioning is planned to start in early 2017 and full LEReC commissioning planned to start in early 2018. The instrumentation systems that will be described include current transformers, BPMs, profile monitors, multi-slit and single slit scanning emittance stations, time-of-flight and magnetic energy measurements, and beam halo & loss monitors.
	Poster TUPG35 [14.455 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG35
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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, laser	475
	M. Yan, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, M. Schedler, T. Schmelzer, M. Schuh, M. Schwarz, B. Smit KIT, Karlsruhe, Germany M.M. Dehler, N. Hiller, R. Ischebeck, V. Schlott PSI, Villigen PSI, Switzerland T. Feurer, M. Hayati Universität Bern, Institute of Applied Physics, Bern, Switzerland
	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.
	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, laser, linac, radiation	483
	K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	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).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG58
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TUPG64	Bunch Length Measurement Based on Interferometric Technique by Observing Coherent Transition Radiation	electron, radiation, linac, detector	498
	I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Generation and diagnosis of ultrashort electron bunches are one of the main topics of accelerator physics and applications in related scientific fields. In this study, ultrashort electron bunches with bunch lengths of femtoseconds and bunch charges of picocoulombs were generated from a laser photocathode RF gun linac and an achromatic arc-type bunch compressor. Observing coherent transition radiation (CTR) emitted from the electron bunches using a Michelson interferometer, the interferograms of CTR were measured experimentally. The bunch lengths were diagnosed by performing a model-based analysis of the interferograms of CTR.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG64
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WEPG19	Conceptual Design of LEReC Fast Machine Protection System	laser, electron, vacuum, dipole	665
	S. Seletskiy, Z. Altinbas, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, L.R. Hammons, J. Hock, P. Inacker, J.P. Jamilkowski, D. Kayran, K. Mernick, T.A. Miller, M.G. Minty, M.C. Paniccia, I. Pinayev, K.S. Smith, P. Thieberger, J.E. Tuozzolo, W. Xu, Z. Zhao BNL, Upton, Long Island, New York, USA
	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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WEPG33	The Measurement and Controlling System of Beam Current for Weak Current Accelerator	electron, target, detector, controls	697
	J.H. Yue, Y. Li, Z.J. Ma, Y. Xie, L. Yu IHEP, Beijing, People's Republic of China
	For some detectors' calibration, a very weak electron current provided by accelerator is necessary. In order to control the beam current to the detector, 8 movable slits in which the position resolution of the stoppers is better than 5μm are installed along the accelerator. For the weak current measurement, 9 movable current monitors based on scintillator are installed along the beam line. These monitors can measure the very weak current, even to several electrons. The monitors can be pulled away the beam axis when the electron beam goes to the downstream.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG33
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WEPG52	Laser Arrival Time Measurement and Correction for the SwissFEL Lasers	laser, timing, FEL, experiment	763
	M.C. Divall, C.P. Hauri, S. Hunziker, A. Romann, A. Trisorio PSI, Villigen PSI, Switzerland
	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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Paper

Title

Other Keywords

Page

MOBL02

First Experience with the Standard Diagnostics at the European XFEL Injector

diagnostics, operation, electron, electronics

14

D. Lipka, A. Affeldt, A. Awwad, N. Baboi, B. Barret, B. Beutner, F. Brinker, W. Decking, A. Delfs, M. Drewitsch, O. Frank, C. Gerth, V. Gharibyan, O. Hensler, M. Hoeptner, M. Holz, K.K. Knaack, F. Krivan, I. Krouptchenkov, J. Kruse, G. Kube, B. Lemcke, T. Lensch, J. Liebing, T. Limberg, B. Lorbeer, J. Lund-Nielsen, S.M. Meykopff, B. Michalek, J. Neugebauer, Re. Neumann, Ru. Neumann, D. Nölle, M. Pelzer, G. Petrosyan, Z. Pisarov, P. Pototzki, G. Priebe, K.R. Rehlich, D. Renner, V. Rybnikov, G. Schlesselmann, F. Schmidt-Föhre, M. Scholz, L. Shi, P.A. Smirnov, H. Sokolinski, C. Stechmann, M. Steckel, R. Susen, H. Tiessen, S. Vilcins, T. Wamsat, N. Wentowski, M. Werner, Ch. Wiebers, J. Wilgen, K. Wittenburg, R. Zahn, A. Ziegler
DESY, Hamburg, Germany
R. Baldinger, R. Ditter, B. Keil, W. Koprek, R. Kramert, G. Marinkovic, M. Roggli, M. Stadler, D.M. Treyer
PSI, Villigen PSI, Switzerland
A. Ignatenko
DESY Zeuthen, Zeuthen, Germany
A. Kaukher
XFEL. EU, Hamburg, Germany
O. Napoly, C. Simon
CEA/DSM/IRFU, France

The injector of the European XFEL is in operation since December 2015. It includes, beside the gun and the accelerating section, containing 1.3 and a 3.9 GHz accelerating module, a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems are installed in the injector. Therefore the operation of the injector is served to validate and prove the diagnostics characteristics for the complete European XFEL. Most of the standard diagnostics has been available for the start of beam operation and showed the evidence of first beam along the beam line. In the following months the diagnostics has been optimized and used for improvements of beam quality. First operational experiences and results from the standard beam diagnostics in the injector of the European XFEL will be reported in this contribution.

Slides MOBL02 [5.844 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOBL02

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MOPG38

Characterization and Simulations of Electron Beams Produced From Linac-Based Intense THz Radiation Source

electron, linac, cathode, radiation

131

N. Chaisueb, S. Rimjaem, J. Saisut
Chiang Mai University, Chiang Mai, Thailand
N. Kangrang
Chiang Mai University, PBP Research Facility, Chiang Mai, Thailand

Electron beams with a maximum energy of 2.5 MeV and a macropulse current of 1 A are produced from a thermionic RF-gun of the linear accelerator system at Chiang Mai University, Thailand. An RF rectangular waveguide and a side coupling cavity of the RF gun introduce asymmetric field distribution inside the gun cavities. To investigate the effect of the asymmetric field distribution on electron beam production and acceleration, measurements and simulations of the electron beam properties were performed. In this study we use well calibrated current transformers, alpha magnet energy slits, and a Michelson interferometer to measure the electron pulse current, the beam energy, and the bunch length, respectively. This paper presents the measurement data of the electron beam properties at various location along the beam transport line and compares the results with the beam dynamic simulations by using the particle tracking program ELEGANT. Moreover, the RF field feature and the cathode power were optimized in order to achieve the high qualities of the electron beam produced from the RF gun. This result implies and correlates to the electron back-bombardment effect inside the gun cavities.
* This work has been supported by the Thailand Center of Excellence in Physics, Faculty of science, Chiang Mai University, and the Science Achievement Scholarship of Thailand (SAST).

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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG38

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MOPG53

Electron Beam Probe Diagnostic for BESSY II Storage Ring

electron, diagnostics, synchrotron, simulation

179

D. Malyutin, A.N. Matveenko
HZB, Berlin, Germany

A low energy electron beam can be used to characterize the high energy ultra-relativistic bunches. This technique allows one to obtain the bunch transverse profiles as well as the bunch length within a non-destructive single shot measurement. In this paper the bunch length measurement technique based on the interaction of the low energy electron beam with an ultra-relativistic bunch is described. Results of numerical simulations of measurements related to BESSY II are presented. A possible setup of such diagnostic system for BESSY II and in future for BESSY VSR is proposed.

Poster MOPG53 [0.868 MB]

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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG53

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TUPG35

LEReC Instrumentation Design & Construction

electron, ion, injection, emittance

417

T.A. Miller, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, J.M. Fite, D.M. Gassner, R.L. Hulsart, D. Kayran, J. Kewisch, C. Liu, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, P. Oddo, M.C. Paniccia, I. Pinayev, S. Seletskiy, K.S. Smith, Z. Sorrell, P. Thieberger, J.E. Tuozzolo, D. Weiss, A. Zaltsman
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
RHIC will be run at low ion beam center-of-mass energies of 7.7 - 20 GeV/nucleon, much lower than the typical operations at 100 GeV/nucleon. The primary motivation is to explore the existence and location of the critical point on the QCD phase diagram. An electron accelerator is being constructed to provide Low Energy RHIC electron Cooling (LEReC) to cool both the blue & yellow RHIC ion beams by co-propagating a 10 - 50 mA electron beam of 1.6 - 2.6 MeV. This cooling facility will include a 400 keV DC gun, SRF booster cavity and a beam transport with multiple phase adjusting RF cavities to bring the beam to one ring to allow electron-ion co-propagation for ~21 m, then through a 180° U-turn electron transport so that the same electron beam can similarly cool the other counter-rotating ion beam, and finally to a beam dump. The injector commissioning is planned to start in early 2017 and full LEReC commissioning planned to start in early 2018. The instrumentation systems that will be described include current transformers, BPMs, profile monitors, multi-slit and single slit scanning emittance stations, time-of-flight and magnetic energy measurements, and beam halo & loss monitors.

Poster TUPG35 [14.455 MB]

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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG35

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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, laser

475

M. Yan, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, M. Schedler, T. Schmelzer, M. Schuh, M. Schwarz, B. Smit
KIT, Karlsruhe, Germany
M.M. Dehler, N. Hiller, R. Ischebeck, V. Schlott
PSI, Villigen PSI, Switzerland
T. Feurer, M. Hayati
Universität Bern, Institute of Applied Physics, Bern, Switzerland

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.

Poster TUPG56 [6.961 MB]

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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, laser, linac, radiation

483

K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

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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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG58

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TUPG64

Bunch Length Measurement Based on Interferometric Technique by Observing Coherent Transition Radiation

electron, radiation, linac, detector

498

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Generation and diagnosis of ultrashort electron bunches are one of the main topics of accelerator physics and applications in related scientific fields. In this study, ultrashort electron bunches with bunch lengths of femtoseconds and bunch charges of picocoulombs were generated from a laser photocathode RF gun linac and an achromatic arc-type bunch compressor. Observing coherent transition radiation (CTR) emitted from the electron bunches using a Michelson interferometer, the interferograms of CTR were measured experimentally. The bunch lengths were diagnosed by performing a model-based analysis of the interferograms of CTR.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG64

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WEPG19

Conceptual Design of LEReC Fast Machine Protection System

laser, electron, vacuum, dipole

665

S. Seletskiy, Z. Altinbas, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, L.R. Hammons, J. Hock, P. Inacker, J.P. Jamilkowski, D. Kayran, K. Mernick, T.A. Miller, M.G. Minty, M.C. Paniccia, I. Pinayev, K.S. Smith, P. Thieberger, J.E. Tuozzolo, W. Xu, Z. Zhao
BNL, Upton, Long Island, New York, USA

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.

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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG19

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WEPG33

The Measurement and Controlling System of Beam Current for Weak Current Accelerator

electron, target, detector, controls

697

J.H. Yue, Y. Li, Z.J. Ma, Y. Xie, L. Yu
IHEP, Beijing, People's Republic of China

For some detectors' calibration, a very weak electron current provided by accelerator is necessary. In order to control the beam current to the detector, 8 movable slits in which the position resolution of the stoppers is better than 5μm are installed along the accelerator. For the weak current measurement, 9 movable current monitors based on scintillator are installed along the beam line. These monitors can measure the very weak current, even to several electrons. The monitors can be pulled away the beam axis when the electron beam goes to the downstream.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG33

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WEPG52

Laser Arrival Time Measurement and Correction for the SwissFEL Lasers

laser, timing, FEL, experiment

763

M.C. Divall, C.P. Hauri, S. Hunziker, A. Romann, A. Trisorio
PSI, Villigen PSI, Switzerland

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.

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reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG52

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