First Measurement of Longitudinal Profile of High-Power and Low-Energy H⁻ Beam by Using Bunch Shape Monitor with Graphite Target
532
R. Kitamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
At J-PARC Linac, bunch shape monitors (BSMs) have been used to measure a longitudinal profile of high power H− beam. Operational principle of the monitor is similar to that of the streak-camera. The BSM inserts a biased-solid target into H− beam to extract and accelerate secondary electrons. These electrons are then modulated with synchronized RF. After passing through dipole B field, a longitudinal profile is converted to a transverse one. For the BSM, a choice of target material is essential to reduce beam loss and to have sufficient tolerance for breakage by the interaction with high power beams. The BSM with graphite target realized the measurement of high-power 3 MeV beam for the first time.
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Experimental Verification and Analysis of Beam Loading Effect Based on Precise Bunch-by-Bunch 3d Position Measurement (remote contribution)
Y.M. Zhou
SSRF, Shanghai, People’s Republic of China
Y.M. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China
Beam loading effect is one of the main bottlenecks of synchrotron radiation light source to further improve performance. The theoretical analysis and numerical simulation of beam loading effect had been done very well, but the corresponding diagnostics tools relatively poor, usually only streak camera is used to observe the synchronous phase distribution and the intensity distribution in bunch train. SSRF developed precise bunch-by-bunch 3D beam position measurement system. Equipped with this system not only steady-state beam parameters (filling pattern, synchronous phase, bunch lifetime), can be accurately measured and recorded, but also transient stage data can be perfectly captured and recorded. Therefore, the beam loading effect can be more comprehensive and accurate experimental verification and analysis. In this paper, the measurement results of synchronous phase, synchronous tune, synchronous oscillation damping time and other parameters with and without third harmonic cavity are introduced and discussed.
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Single-Shot Electro-Optic Detection of Bunch Shapes and THz Pulses: Fundamental Temporal Resolution Limitations and Cures Using the DEOS Strategy
536
C. Szwaj, S. Bielawski, C. Evain, E. Roussel
PhLAM/CERLA, Villeneuve d’Ascq, France
C. Gerth, B. Steffen
DESY, Hamburg, Germany
B. Jalali
UCLA, Los Angeles, California, USA
Funding:ULTRASYNC ANR-DFG project, CPER Photonics for Society, CEMPI LABEX Recording electric field evolutions in single-shot and with sub-picosecond resolution is required in electron bunch diagnostics, and THz applications. A popular strategy consists of transferring the unknown electric field shape onto a chirped laser pulse, which is eventually analyzed. The technique has been investigated and/or been used as routine diagnostics at FELIX, DESY, PSI, Eu-XFEL, KARA, SOLEIL, etc. However fundamental time-resolution limitations have been strongly limiting the potential of these methods. We review recent results on a strategy designed for overcoming this limit: DEOS [1] (Diversity Electro-Optic Sampling). A special experimental design enables to reconstruct numerically the input electric signal with unprecedented temporal resolution. As a result, 200 fs temporal resolution over more than 10 ps recording length could be obtained at European XFEL - a performance that could not be realized using classical spectrally-decoded electro-optic detection. Although DEOS uses a radically novel conceptual approach, its implementation requires few hardware modifications of currently operating chirped pulse electro-optic detection systems. [1] E. Roussel, C. Szwaj, C. Evain, B. Steffen, C. Gerth, B. Jalali and S. Bielawski, Light: Science & Applications 11, 14 (2022). https://www.nature.com/articles/s41377-021-00696-2
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Advancing the Steady State Microbunching Experiment at the MLS With an Enhanced Detection Scheme
A. Kruschinski, J. Feikes
HZB, Berlin, Germany
A. Hoehl, R. Klein, J. Puls
PTB, Berlin, Germany
The Steady State Microbunching (SSMB) Proof-of-Principle experiment at the Metrology Light source (MLS) has shown the viability of the concept and investigates the physics behind the mechanism of microbunching, which is envisioned to provide very high power coherent synchrotron radiation at a storage ring facility. In the initial stages of the experiment, it was not possible to detect the coherent radiation of interest directly. A new detection scheme that overcomes this difficulty using fast optical switches is presented, as well as newest results obtained.
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