Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility

Schietinger, T.; Hauff, Andreas; Pal, T.; Krempaská, R.; Arsov, V.; Divall, E. J.; Raguin, Jean-Yves; Kaiser, M.; Pollet, P.; Janousch, M.; Higgs, Colin; Schär, M.; Chrin, J.; Citterio, A.; Divall, M.; Armstrong, D.; Calvi, M.; Loch, Cigdem Ozkan; Marcellini, F.; Scherrer,; Chevtsov, P.; Schmidt, Th.; Milas, Natalia; Ganter, R.; Anic̈ić, D.; Zennaro, R.; Vicario, C.; Prat, Eduard; Smit, Bennie; Lippuner, Thomas; Treyer, Daniel; Lehner, S.; Baldinger, R.; Orlandi, Gian Luca; Kim, Y.; Dach, M.; Hämmerli, F.; Stadler, Markus; Korhonen, T.; Bertrand, Alexander; Ischebeck, R.; Brands, Helge; Hugentobler, W.; Dehler, M.; Ditter, R.; Rohrer, Martin; Dax, A.; Schilcher, T.; Braun, Hans-Heinrich; Frei, Franziska; Baldinger, M.; Falone, Antonio; Peier, Peter; Tron, W.; Sturzenegger, W.; Menzel, Ralf; Ritt, S.; Reiche, S.; Janser, G.; Mair, S.; Guetg, Marc; Trisorio, A.; Stingelin, L.; Bitterli, Kurt; Bopp, M.; Fitze, H.; Schlott, V.; Aiba, M.; Řežaeizadeh, Amin; Brönnimann, M.; Brunnenkant, I.; Craievich, P.; Portmann, Werner; Lutz, H.F.; Schebacher, L.; Marinković, Goran; Kalt, Roger; Hauri, Christoph P.; Zimoch, D.; Wiegand, P.; Laznovsky, M.; Bettoni, S.; Schulz, Lothar; Pimpec, F. Le; Steffen, B.; Hunziker, S.; Löhl, Florian; Keil, Boris; Ivanisenko, Y.; Geiselhart, C.; Pedrozzi, M.; Koprek, Waldemar; Heiniger, M.; Zimoch, Elke; Beutner, Bolko; Kalantari, B.

doi:10.1103/physrevaccelbeams.19.100702

Cited by 48 publications

(30 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on an rf vector-modulator [26], it allows a timing delay from 80 fs up to several tens of nanoseconds. For superperiod synchronization, the FO repetition rate is compared to a 55.5 MHz rf signal derived from the MO at the FEL facility, which is transferred via a separate, non-stabilized fiber link [27].…”

Section: B Table-top Laser and Synchronizationmentioning

confidence: 99%

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Kiessling

Colson

Gewinner

et al. 2018

Phys. Rev. Accel. Beams

View full text Add to dashboard Cite

We experimentally demonstrate a single-shot arrival time monitor for short picosecond infrared freeelectron laser (IR FEL) pulses based on balanced optical cross-correlation with a synchronized fs table-top laser. Employing this timing tool at the Fritz Haber Institute IR FEL, we observe a shot-to-shot timing jitter of only 100 fs and minute-scale timing drifts of a few picoseconds, the latter being strictly correlated with the electron beam energy of the accelerator. We acquire sum-frequency cross-correlation data with micropulse resolution, providing full access to the IR FEL pulse shape evolution within the macropulse. These measurements provide unprecedented insights into the occurrence of limit-cycle oscillations of the FEL intensity as a consequence of subpulse formation. Our experimental results are complemented by fourdimensional simulations of the nonlinear pulse dynamics in a low-gain FEL oscillator based on MaxwellLorentz theory.

show abstract

Section: B Table-top Laser and Synchronizationmentioning

confidence: 99%

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Kiessling

Colson

Gewinner

et al. 2018

Phys. Rev. Accel. Beams

View full text Add to dashboard Cite

show abstract

“…SwissFEL is a X-ray FEL facility [15][16][17] in operation at Paul Scherrer Institut. Driven by a rf linac -a S-band injector and a C-band accelerator -in the beam energy range 2.1 − 5.8 GeV, SwissFEL is presently producing tunable and coherent hard X-ray pulses in the wavelength region 0.7 − 0.1 nm (ARAMIS undulator line) and, by 2021, will also generate soft X-ray radiation in the wavelength region 7 − 0.7 nm (ATHOS undulator line).…”

Section: Experimental Set-up and Resultsmentioning

confidence: 99%

Nanofabricated free-standing wire scanners for beam diagnostics with submicrometer resolution

Orlandi

Dávid²,

Guzenko³

et al. 2020

Phys. Rev. Accel. Beams

Self Cite

View full text Add to dashboard Cite

Diagnostics of the beam transverse profile with ever more demanding spatial resolution is required by the progress on novel particle accelerators -such as laser and plasma driven accelerators -and by the stringent beam specifications of the new generation of X-ray facilities. In a linac driven Free-Electron-Laser (FEL), the spatial resolution constraint joins with the further requirement for the diagnostics to be minimally invasive in order to protect radiation sensitive components -such as the undulators -and to preserve the lasing mechanism. As for high resolution measurements of the beam transverse profile in a FEL, wire-scanners (WS) are the top-ranked diagnostics. Nevertheless, conventional WS consisting of a metallic wire (beam-probe) stretched onto a frame (fork) can provide at best a rms spatial resolution at the micrometer scale along with an equivalent surface of impact on the electron beam. In order to improve the spatial resolution of a WS beyond the micrometer scale along with the transparency to the lasing, PSI and FERMI are independently pursuing the technique of the nano-lithography to fabricate a free-standing and sub-micrometer wide WS beam-probe fully integrated into a fork. Free-standing WS with a geometrical resolution of about 250 nm have been successfully tested at SwissFEL where low charge electron beams with a vertical size of 400 − 500 nm have been characterized. Further experimental tests carried out at SwissFEL at the nominal beam charge of 200 pC confirmed the resilience to the heat-loading of the nano-fabricated WS. In this work, details on the nano-fabrication of free-standing WS as well as results of the electron-beam characterization are presented.

show abstract

“…Its accelerating frequency matches the target frequency, the peak electric field on the cavity surface is slightly lower than for CAVITY #1, i.e., F 3 is slightly better, but the shunt impedance is not as high, i.e., F 2 is not as good, though it is still better than the corresponding value for ELETTRA 2D. Since ELETTRA 2D is only an axisymmetric approximation, the longitudinal growth rate is above the threshold b, defined in (7), for three of its HOMs. The value of F 4 is zero for CAVITY #2, and, coincidentally, also for CAVITY #1, even though it was not an objective in the optimization.…”

Section: Generation 200mentioning

confidence: 90%

Multi-objective shape optimization of radio frequency cavities using an evolutionary algorithm

Kranjčević

Adelmann

Arbenz

et al. 2019

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

Radio frequency (RF) cavities are commonly used to accelerate charged particle beams. The shape of the RF cavity determines the resonant electromagnetic fields and frequencies, which need to satisfy a variety of requirements for a stable and efficient acceleration of the beam. For example, the accelerating frequency has to match a given target frequency, the shunt impedance usually has to be maximized, and the interaction of higher order modes with the beam minimized. In this paper we formulate such problems as constrained multi-objective shape optimization problems, use a massively parallel implementation of an evolutionary algorithm to find an approximation of the Pareto front, and employ a penalty method to deal with the constraint on the accelerating frequency. Considering vacuated axisymmetric RF cavities, we parameterize and mesh their cross section and then solve time-harmonic Maxwell's equations with perfectly electrically conducting boundary conditions using a fast 2D Maxwell eigensolver. The specific problem we focus on is the hypothetical problem of optimizing the shape of the main RF cavity of the planned upgrade of the Swiss Synchrotron Light Source (SLS), called SLS-2. We consider different objectives and geometry types and show the obtained results, i.e., the computed Pareto front approximations and the RF cavity shapes with desired properties. Finally, we compare these newfound cavity shapes with the current cavity of SLS.cavities with resonant frequencies of 70 MHz power the cyclotron of the PROSCAN facility for cancer treatment. In the storage ring of the Swiss Synchrotron Light Source (SLS), four 500 MHz ELETTRA-type [5] cavities compensate for the energy loss due to synchrotron radiation and focus the electron bunches in longitudinal direction. A pair of passive superconducting cavities with operation frequency at the third harmonic provide bunch lengthening and Landau damping [6]. The newest accelerator at PSI is the SwissFEL facility [7], with pulsed RF cavities at operation frequencies of 3, 5.7 and 12 GHz. Compared to other PSI facilities, where standing wave cavities are used, most of the cavities of the SwissFEL LINAC are of the traveling wave cavity type. Other than for beam acceleration, RF cavities are also used for beam diagnostics, like beam current and position monitors [8,9], for bunch rotation in deflecting cavities [10], or in power amplifiers of accelerators, like klystrons, or filters.PSI is currently elaborating an upgrade proposal for SLS, called SLS-2 [11], for dramatically improved synchrotron light quality. This process is triggered by the development of distributed vacuum pumping, which allowed a reduction of the vacuum chamber dimensions, larger number and more compact magnets, and advancements in high precision machining. It is foreseen to reuse the existing main cavities, extended by a new type of absorber for the most troubling beam excited higher order modes (HOMs).In order to efficiently accelerate the beam, the RF cavity has to be optimized and engineered to satis...

show abstract

Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility

Cited by 48 publications

References 97 publications

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Nanofabricated free-standing wire scanners for beam diagnostics with submicrometer resolution

Multi-objective shape optimization of radio frequency cavities using an evolutionary algorithm

Contact Info

Product

Resources

About