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Goryashko, Vitaliy
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Publications (10 of 42) Show all publications
Mak, A., Shamuilov, G., Salén, P., Dunning, D., Hebling, J., Kida, Y., . . . Goryashko, V. (2019). Attosecond single-cycle undulator light: a review. Reports on progress in physics (Print), 82(2), Article ID 025901.
Open this publication in new window or tab >>Attosecond single-cycle undulator light: a review
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2019 (English)In: Reports on progress in physics (Print), ISSN 0034-4885, E-ISSN 1361-6633, Vol. 82, no 2, article id 025901Article, review/survey (Refereed) Published
Abstract [en]

Research at modern light sources continues to improve our knowledge of the natural world, from the subtle workings of life to matter under extreme conditions. Free-electron lasers, for instance, have enabled the characterization of biomolecular structures with sub-angstrom spatial resolution, and paved the way to controlling the molecular functions. On the other hand, attosecond temporal resolution is necessary to broaden our scope of the ultrafast world. Here we discuss attosecond pulse generation beyond present capabilities. Furthermore, we review three recently proposed methods of generating attosecond x-ray pulses. These novel methods exploit the coherent radiation of microbunched electrons in undulators and the tailoring of the emitted wavefronts. The computed pulse energy outperforms pre-existing technologies by three orders of magnitude. Specifically, our simulations of the proposed Soft X-ray Laser at MAX IV (Lund, Sweden) show that a pulse duration of 50-100 as and a pulse energy up to 5 mu J is feasible with the novel methods. In addition, the methods feature pulse shape control, enable the incorporation of orbital angular momentum, and can be used in combination with modern compact free-electron laser setups.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2019
Keywords
free-electron lasers, mode locking, undulator radiation, UV and x-ray lasers, ultrafast optics, charge migration in molecules, attosecond pump-probe capabilities
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-377103 (URN)10.1088/1361-6633/aafa35 (DOI)000456325700001 ()30572315 (PubMedID)
Funder
Swedish Research Council, 2016-04593The Royal Swedish Academy of Sciences, PH2018-0037
Available from: 2019-02-19 Created: 2019-02-19 Last updated: 2019-02-19Bibliographically approved
Li, H., Jobs, M., Santiago Kern, R., Goryashko, V. A., Hermansson, L., Bhattacharyya, A., . . . Ruber, R. (2019). Characterization of a beta=0.5 double spoke cavity with a fixed power coupler. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 927, 63-69
Open this publication in new window or tab >>Characterization of a beta=0.5 double spoke cavity with a fixed power coupler
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2019 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 927, p. 63-69Article in journal (Refereed) Published
Abstract [en]

ESS, the European Spallation Source, will adopt a single family of double spoke cavities for accelerating the beam from the normal conducting section to the first family of the elliptical superconducting cavities. It will be the first double spoke cavities in the world to be commissioned for a high power proton accelerator. The first double spoke cavity for the ESS project was tested with high power in the HNOSS cryostat at Uppsala University. A pulse-mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involves a double-spoke superconducting cavity, a fixed fundamental power coupler, tuner, a low-level radiofrequency (LLRF) system and a high-power radiofrequency (RF) station. The test represents an important verification milestone before the module assembly. This cavity had unfortunately a high dynamic loss of 12W @ 9 MV/m, where potential causes for such a high value have been studied and corresponding suggestions are listed. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.

Keywords
Double spoke cavity, High power test, Self-excited loop
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-382240 (URN)10.1016/j.nima.2019.02.003 (DOI)000462142700008 ()
Funder
EU, Horizon 2020, 730871
Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-05-16Bibliographically approved
Mak, A., Salén, P. & Goryashko, V. (2019). Compact undulator line for a high-brilliance soft-X-ray free-electron laser at MAX IV. Journal of Synchrotron Radiation, 26, 891-898
Open this publication in new window or tab >>Compact undulator line for a high-brilliance soft-X-ray free-electron laser at MAX IV
2019 (English)In: Journal of Synchrotron Radiation, ISSN 0909-0495, E-ISSN 1600-5775, Vol. 26, p. 891-898Article in journal (Refereed) Published
Abstract [en]

The optimal parameter space for an X-ray free-electron laser (FEL) in the self-amplified spontaneous emission (SASE) operation mode is examined. This study focuses on FEL operation with a shorter undulator period and higher undulator strength made available through recent developments in in-vacuum, cryogenic and superconducting undulators. Progress on short-period undulator technologies is surveyed and FEL output characteristics versus undulator parameters are computed. The study is performed on a case of the planned soft-X-ray FEL at the MAX IV Laboratory in Sweden. An extension of the SASE mode into the harmonic lasing self-seeded mode is also analysed.

Place, publisher, year, edition, pages
INT UNION CRYSTALLOGRAPHY, 2019
Keywords
undulator technologies, X-ray free-electron lasers, high brilliance, self-amplified spontaneous emission, harmonic lasing self-seeding
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-385561 (URN)10.1107/S160057751900290X (DOI)000467526100032 ()31074454 (PubMedID)
Funder
EU, Horizon 2020, 777431Swedish Research Council, 2016-04593Swedish National Infrastructure for Computing (SNIC), SNIC 2017/7-338The Royal Swedish Academy of Sciences, PH2018-0037
Available from: 2019-06-19 Created: 2019-06-19 Last updated: 2019-06-19Bibliographically approved
Mak, A., Salén, P., Goryashko, V. & Clarke, J. (2019). Science Requirements and Performance Specification forthe CompactLight X-Ray Free-Electron Laser.
Open this publication in new window or tab >>Science Requirements and Performance Specification forthe CompactLight X-Ray Free-Electron Laser
2019 (English)Report (Other academic)
Abstract [en]

CompactLight is a consortium funded by the European Union through the Horizon 2020 Research and Innovation Programme under Grant Agreement No. 777431.  This report summarizes science requirements and performance specification for the CompactLight x-ray free-electron laser. 

Publisher
p. 18
Series
FREIA Report ; 2019/01
National Category
Accelerator Physics and Instrumentation
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-374175 (URN)
Funder
EU, Horizon 2020, 777431
Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2019-01-18Bibliographically approved
Goryashko, V., Jobs, M., Hoang, L., Eriksson, J. & Ruber, R. (2018). 12-Way 100 kW Reentrant Cavity-Based Power Combiner With Doorknob Couplers. IEEE Microwave and Wireless Components Letters, 28(2), 111-113
Open this publication in new window or tab >>12-Way 100 kW Reentrant Cavity-Based Power Combiner With Doorknob Couplers
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2018 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 2, p. 111-113Article in journal (Refereed) Published
Abstract [en]

We present radio frequency (RF) and thermal characterization of a compact 12-way power combiner designed for operation at 352 MHz at a power level of 100 kW with 5% duty factor. The combiner is based on a reentrant cavity with 12 input doorknob couplers and one output coupler that is integrated with the post of the cavity and forms doorknob type geometry. We introduce convenient design formulas that allow easy identification of a suitable parameter space, which is then refined with numerical simulations. Low-power RF measurements of a prototype show 0.2% insertion loss and a relative rms amplitude imbalance between the ports of 0.1% and phase imbalance of 0.036 degrees rms. The matching is better than -25 dB over a 3-dB bandwidth around the design frequency. We also tested the combiner up to 200 kW and found the RF loss to be comparable to that of the low-power measurement. In a long test run at 100 kW with 5% duty factor, the combiner temperature stabilized at 10 degrees above ambient.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
High-power handling capability, high-power radio frequency (RF) measurements, power combiner, thermal study
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-349845 (URN)10.1109/LMWC.2017.2780619 (DOI)000425173500007 ()
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-05-03Bibliographically approved
Shamuilov, G., Mak, A., Salén, P. & Goryashko, V. (2018). Analytical model of waveform-controlled single-cycle light pulses from an undulator. Optics Letters, 43(4), 819-822
Open this publication in new window or tab >>Analytical model of waveform-controlled single-cycle light pulses from an undulator
2018 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 43, no 4, p. 819-822Article in journal (Refereed) Published
Abstract [en]

This Letter builds upon a recent concept [Phys. Rev. Lett. 113, 104801 (2014)] for producing ultrashort optical pulses through the coherent radiation of electrons in an undulator. Each pulse contains only a single oscillation cycle, and has a controlled waveform (and hence a stable carrier-envelope phase). While the concept had been demonstrated numerically, this Letter provides an analytical model for the radiation mechanism, thereby revealing three key observations: (i) the correlation between the waveforms of the optical and undulator fields; (ii) the free-space dispersion of transversely confined light; and (iii) the dependence of the optical pulse shape on the undulator field strength.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-349360 (URN)10.1364/OL.43.000819 (DOI)000425123700049 ()29444002 (PubMedID)
Funder
Swedish Research Council, 2016-04593
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-04-26Bibliographically approved
Shamuilov, G., Mak, A., Pepitone, K. & Goryashko, V. (2018). Child-Langmuir law for photoinjectors. Applied Physics Letters, 113(20), Article ID 204103.
Open this publication in new window or tab >>Child-Langmuir law for photoinjectors
2018 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 113, no 20, article id 204103Article in journal (Refereed) Published
Abstract [en]

The space-charge field at the cathode limits the current density extracted from particle sources such as photoinjectors. For a long time, the maximum current has been estimated by using the classical Child-Langmuir law, which is derived with an assumption inconsistent with the conditions of modern laser-driven electron guns. Here, we introduce a theoretical model that accurately accounts for space-charge effects in transversely confined particle beams emerging from photocathodes. The model enables us to (i) determine the maximum current density extractable from the photocathode for an arbitrary cathode radius, (ii) reveal its dependence on the transverse profile of the particle beam, and (iii) predict its upper limit for structured beams such as the ones produced by surface-plasmon resonance-enhanced photocathodes.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-371542 (URN)10.1063/1.5063888 (DOI)000450279900035 ()
Funder
Swedish Research Council, 2016-04593
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Opanasenko, A. M. & Goryashko, V. (2018). Multislice Model Of Electron Bunch For Study Of Ballistic Bunching Of Low Emittance Beams. Problems Of Atomic Science And Technology (3), 73-80
Open this publication in new window or tab >>Multislice Model Of Electron Bunch For Study Of Ballistic Bunching Of Low Emittance Beams
2018 (English)In: Problems Of Atomic Science And Technology, ISSN 1562-6016, no 3, p. 73-80Article in journal (Refereed) Published
Abstract [en]

At ballistic bunching of an electron beam the transverse distribution of space-charge field varies along a bunch greatly. It can lead to emittance growth unless to provide its compensation. To study this problem, a multislice model of a bunch of relativistic charged particles that needs no smallness of energy spread between slices are developed. This removes the limit on the value of the RF field that modulates the slices by velocity before their injection into a drift space. The longitudinal dynamics of each slice is determined by its interaction with the field of the entire bunch averaged over the slice. Transverse beam characteristics are found from a differential equation for root-mean-square envelope of a beam.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-372426 (URN)000451570000016 ()
Funder
Swedish Research Council
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Hoang Duc, L., Bhattacharyya, A., Goryashko, V., Ruber, R., Olsson, J. & Dancila, D. (2018). Time Domain Characterization of High Power Solid State Amplifiers for the Next Generation Linear Accelerators. Microwave and optical technology letters (Print), 60(1), 163-171
Open this publication in new window or tab >>Time Domain Characterization of High Power Solid State Amplifiers for the Next Generation Linear Accelerators
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2018 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 60, no 1, p. 163-171Article in journal (Refereed) Published
Abstract [en]

This paper presents the time domain characterization of high power pulsed solid state amplifiers to be used forlinear accelerator applications. The study comprises nonlinear circuit envelope simulations and time domainenvelope measurements. Measurements and simulations are performed under the pulsed conditions (3.5 mspulse width, 5% duty cycle) specific to the European Spallation Source (ESS) high intensity proton accelerator.We measure the characteristics of pulsed LDMOS based power amplifiers such as: pulse droop along the pulse,efficiency, average envelope pulse amplitude and phase, pulse drain current waveform, pulse drain voltagewaveform, etc. A comparison between the measured results and the simulated results is also presented. Inaddition to the pulse profile characterization, the pulse to pulse (P2P) stability of the presented solid state poweramplifier (SSPA) is investigated as variations of amplitude and phase. The P2P stability simulations areintroduced as a combination of the Monte-Carlo simulations and the nonlinear circuit envelope simulations. Thesimulated results are used for fitting the P2P measurements to give an early insight of causes of instabilities ofthe nonlinear LDMOS models.

Keywords
accelerator, solid state amplifiers, LDMOS, nonlinear circuit envelope, time domain envelope measurements, pulse profile
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-334910 (URN)10.1002/mop.30926 (DOI)000416937700028 ()
Projects
ESS
Available from: 2017-11-29 Created: 2017-11-29 Last updated: 2018-02-28Bibliographically approved
Mak, A., Salén, P. & Goryashko, V. (2018). Undulator Considerations in the Baseline Design of the MAX IV Soft X-Ray Laser.
Open this publication in new window or tab >>Undulator Considerations in the Baseline Design of the MAX IV Soft X-Ray Laser
2018 (English)Report (Other academic)
Abstract [en]

We examine the optimal parameter space for an x-ray free-electron laser (FEL) in the operation mode of self-amplified spontaneous emission (SASE). The study focuses on FEL operation with a shorter undulator period and higher undulator strength made available through recent developments in in-vacuum, cryogenic and superconducting undulators. We survey the progress on short-period undulator technologies and compute the FEL output characteristics versus the undulator parameters. We perform the study on a case of the planned soft-x-ray FEL at the MAX IV Laboratory in Sweden. An extension of the SASE mode into the harmonic lasing self-seeded mode is also analysed.

Publisher
p. 16
Series
FREIA Report ; 2018-4
National Category
Accelerator Physics and Instrumentation
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-357900 (URN)
Funder
Swedish Research Council, 2016-04593The Royal Swedish Academy of Sciences, PH2018- 0037EU, Horizon 2020, 777431
Available from: 2018-08-21 Created: 2018-08-21 Last updated: 2018-08-22Bibliographically approved
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