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194 results on '"Burian T"'

52. Measurements of continuum lowering in solid-density plasmas created from elements and compounds

Author

Ciricosta, O., primary, Vinko, S. M., additional, Barbrel, B., additional, Rackstraw, D. S., additional, Preston, T. R., additional, Burian, T., additional, Chalupský, J., additional, Cho, B. I., additional, Chung, H. -K., additional, Dakovski, G. L., additional, Engelhorn, K., additional, Hájková, V., additional, Heimann, P., additional, Holmes, M., additional, Juha, L., additional, Krzywinski, J., additional, Lee, R. W., additional, Toleikis, S., additional, Turner, J. J., additional, Zastrau, U., additional, and Wark, J. S., additional

Published
2016
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53. Multiple pulse damage in Mo/Si multilayer optics irradiated by intense short-wavelength FELs

Author

Sobierajski, R., Loch, R.A., Louis, Eric, Klinger, D., Dluizewski, P., Klepka, M., Bijkerk, Frederik, Burian, T., Chalupsky, J., Coppola, N., Dastjani Farahani, S., Galasso, G., Hajkova, V., Harmand, M., Krzywinski, J., Juha, L., Jurek, M., Möller, S., Nagasono, M., Ozkan, C., Pelka, J.B., Saskl, K., Schulz, J., Sovak, P., Toleikis, S., Tiedtke, K., Vysin, L., Wawro, A., Gaudin, J., and XUV Optics

Subjects
METIS-299691
Published
2013

54. A Motion-aware Data Transfers Scheduling for Distributed Virtual Walkthrough Applications

Author

Pribyl, J., Pavel Zemcik, Burian, T., Kudlac, B., Oliviera, Manuel M., and Skala, Václav

Subjects
pohybová funkce, distributed virtual walkthrough, motion function, virtual environments, Markov chain, data transfers, distribuovaný virtuální průchod, přenosy dat, Markovův řetězec, virtuální prostředí
Abstract

Data transfers scheduling is an important part of almost all distributed virtual walkthrough (DVW) applications. Its main purpose is to preserve data transfer efficiency and render quality during scene exploration. The most limiting factors here are network restrictions such as low bandwidth and high latency. Current scheduling algorithms use multi-resolution data representation, priority determination and data prefetching algorithms to minimize these restrictions. Advanced priority determination and data prefetching methods for DVW applications use mathematic description of motion to predict next position of each individual user. These methods depend on the recent motion of a user so that they can accurately predict only near locations. In the case of sudden but regular changes in user motion direction (road networks) or fast moving user, these algorithms are not sufficient to predict future position with required accuracy and at required distances. In this paper we propose a systematic solution to scheduling of data transfer for DVW applications which uses next location prediction methods to compute download priority or additionally prefetch rendered data in advance. Experiments show that compared to motion functions the proposed scheduling scheme can increase data transfer efficiency and rendered image quality during scene exploration.

Published
2013

55. First commissioning results of the KB mirrors at the SCS instrument of the European XFEL

Author

Assoufid, Lahsen, Ohashi, Haruhiko, Asundi, Anand, Mercurio, G., Broers, C., Carley, R., Delitz, J. T., Gerasimova, N., Le Guyarder, L., Mercadier, L., Reich, A., Schlappa, J., Teichmann, M., Yaroslavtsev, A., Cascella, M., Setoodehnia, K., Schneider, M., Pfau, B., Eisebitt, S., Vozda, V., Hájková, V., Vyšín, L., Burian, T., Chalupský, J., Juha, L., Alcock, S. G., Nistea, I., La Civita, D., Sinn, H., Vannoni, M., and Scherz, A.

Published
2019
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56. Damage of multilayer optics under irradiation with multiple femtosecond XUV pulses

Author

Sobierajski, R., Loch, R.A., Klinger, D., Dluzewski, P., Klepka, M., Burian, T., Chalupsky, J., Visin, L., Farahani, S.D., Hajkova, V., Harmand, M., Krzywinski, J., Juha, L., Jurek, M., Möller, S., Nagasono, M., Ozkan, C., Saskl, K., Sinn, H., Sovak, P., Toleikis, S., and Gaudin, J.

Subjects
METIS-298895
Published
2012

57. Ultrafast thermal damage mechanisms in Mo/Si based multilayers for short-wavelength Free Electron Lasers

Author

Loch, R.A., Sobierajski, R., Bostedt, C., Bozek, J., Burian, T., Chalupsky, J., Gaudin, J., Graf, A., Grzonka, J., Hajkova, V., Hau-Riege, S., van Hattum, E.D., Juha, L., Kllinger, D., Krzywinski, J., London, R.A., Louis, Eric, Messerschmidt, M., Moeller, S., Plocinski, T., Wawro, A., Zabierowski, P., Bijkerk, Frederik, and Laser Physics & Nonlinear Optics

Subjects
METIS-294426
Abstract

Multilayer coated optics are promising candidates for optical schemes at XUV & X-ray Free Electron Lasers (FELs), including the (possible) new ZFEL in The Netherlands. However, due to the extremely high photon flux of these FELs, damage of any optical surface is a possible limitation. Therefore, resistivity studies of MoSi multilayers for different wavelengths were carried out at FLASH and LCLS. The results show that the leading damage mechanism is melting of the amorphous silicon layers, followed by Mo atoms diffusion into Si, leading to molybdenum-silicide formation. Although a similar final state of damage was observed, the damage threshold appeared to be strongly wavelength dependent and is related to the absorbed energy density.

Published
2012

58. Imprinting a Focused X-Ray Laser Beam to Measure Its Full Spatial Characteristics

Author

Chalupský, J., primary, Boháček, P., additional, Burian, T., additional, Hájková, V., additional, Hau-Riege, S. P., additional, Heimann, P. A., additional, Juha, L., additional, Messerschmidt, M., additional, Moeller, S. P., additional, Nagler, B., additional, Rowen, M., additional, Schlotter, W. F., additional, Swiggers, M. L., additional, Turner, J. J., additional, and Krzywinski, J., additional

Published
2015
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59. Damage mechanisms in Mo/Si multilayer optics for short-wavelengths FELs

Author

Loch, R. A., Sobierajski, R., Bostedt, C., Bozek, J., Bruijn, S., Burian, T., Castagna, J. C., Chalupsky, J., Feng, Y., Gaudin, J., Graf, A., Hajkova, V., Hattum, E. D., Hau-Riege, S., Robbert van de Kruijs, Klinger, D., Krzywinski, J., Jastrow, U., Juha, L., Eric Louis, Messerschmidt, M., Moeller, S., Tiedtke, K., Frederik Bijkerk, Laser Physics & Nonlinear Optics, and Discrete Mathematics and Mathematical Programming

Subjects
METIS-270310
Published
2010

60. Fluence thresholds for grazing incidence hard x-ray mirrors

Author

Aquila, A., primary, Sobierajski, R., additional, Ozkan, C., additional, Hájková, V., additional, Burian, T., additional, Chalupský, J., additional, Juha, L., additional, Störmer, M., additional, Bajt, S., additional, Klepka, M. T., additional, Dłużewski, P., additional, Morawiec, K., additional, Ohashi, H., additional, Koyama, T., additional, Tono, K., additional, Inubushi, Y., additional, Yabashi, M., additional, Sinn, H., additional, Tschentscher, T., additional, Mancuso, A. P., additional, and Gaudin, J., additional

Published
2015
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61. Investigation of femtosecond collisional ionization rates in a solid-density aluminium plasma

Author

Vinko, S. M., primary, Ciricosta, O., additional, Preston, T. R., additional, Rackstraw, D. S., additional, Brown, C.R.D., additional, Burian, T., additional, Chalupský, J., additional, Cho, B. I., additional, Chung, H.-K., additional, Engelhorn, K., additional, Falcone, R. W., additional, Fiokovinini, R., additional, Hájková, V., additional, Heimann, P. A., additional, Juha, L., additional, Lee, H. J., additional, Lee, R. W., additional, Messerschmidt, M., additional, Nagler, B., additional, Schlotter, W., additional, Turner, J. J., additional, Vysin, L., additional, Zastrau, U., additional, and Wark, J. S., additional

Published
2015
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62. Saturable Absorption of an X-Ray Free-Electron-Laser Heated Solid-Density Aluminum Plasma

Author

Rackstraw, D. S., primary, Ciricosta, O., additional, Vinko, S. M., additional, Barbrel, B., additional, Burian, T., additional, Chalupský, J., additional, Cho, B. I., additional, Chung, H.-K., additional, Dakovski, G. L., additional, Engelhorn, K., additional, Hájková, V., additional, Heimann, P., additional, Holmes, M., additional, Juha, L., additional, Krzywinski, J., additional, Lee, R. W., additional, Toleikis, S., additional, Turner, J. J., additional, Zastrau, U., additional, and Wark, J. S., additional

Published
2015
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63. Single shot damage mechanism of Mo/Si multilayer optics under intense pulsed XUV-exposure

Author

Khorsand, A.R., Sobierajski, R., Louis, E., Bruijn, S., Van Hattum, E.D., Vande Kruijs, R.W.E., Jurek, M., Klinger, D., Pelka, J.B., Juha, L., Burian, T., Chalupsky, J., Cihelka, J., Hajkova, V., Vysin, L., Jastrow, U., Stojanovic, Nenad, Toleikis, S., Wabnitz, H., Tiedtke, K., Sokolowski-Tinten, Klaus, Shymanovich, Uladzimir, Krzywinski, J., Riege Hau, S., London, R., Gleeson, A., Gullikson, E.M., Bijkerk, F., van de Kruijs, R. W. E., Hau-Riege, S., Faculty of Science and Technology, XUV Optics, and Laser Physics & Nonlinear Optics

Subjects
Silicon, Materials science, Ultraviolet Rays, chemistry.chemical_element, law.invention, Optics, Optical microscope, law, Materials Testing, Thin film, Reflectometry, Molybdenum, business.industry, Optical Devices, Membranes, Artificial, Equipment Design, Nanosecond, Physik (inkl. Astronomie), Laser, Atomic and Molecular Physics, and Optics, Equipment Failure Analysis, chemistry, Extreme ultraviolet, business, Ultrashort pulse
Abstract

We investigated single shot damage of Mo/Si multilayer coatings exposed to the intense fs XUV radiation at the Free-electron LASer facility in Hamburg - FLASH. The interaction process was studied in situ by XUV reflectometry, time resolved optical microscopy, and "post-mortem" by interference-polarizing optical microscopy (with Nomarski contrast), atomic force microscopy, and scanning transmission electron microcopy. An ultrafast molybdenum silicide formation due to enhanced atomic diffusion in melted silicon has been determined to be the key process in the damage mechanism. The influence of the energy diffusion on the damage process was estimated. The results are of significance for the design of multilayer optics for a new generation of pulsed (from atto- to nanosecond) XUV sources. (C)2010 Optical Society of America

Published
2010

64. Spot size characterization of focused non-Gaussian beams

Author

Chalupský, J., Krzywinski, J., Juha, L., Hájková, V., Cihelka, J., Burian, T., Vyšín, L., Gaudin, J., Gleeson, A.J., Jurek, M., Khorsand, A.R., Klinger, D., Wabnitz, H., Sobierajski, R., Störmer, M., Tiedtke, K., Toleikis, S., and XUV Optics

Abstract

We present a new technique for the analysis of non-Gaussian laser beams which can not be described by an analytical formula. As a generalization of the beam spot area we apply and extend the definition of so called effective area (Aeff) [1] in order to avoid using the full-width at half maximum (FWHM) parameter which might be misleading for non-Gaussian beams. Furthermore, we demonstrate a practical utilization of our technique for a femtosecond soft x-ray free electron laser. The ablative imprints in poly(methyl methacrylate) - PMMA and amorphous carbon (a-C) are used to characterize the spatial beam profile and to determine the effective area. Two procedures of the effective area determination and their further utilization are presented in this paper

Published
2010

65. Damage of amorphous carbon induced by soft x-ray femtosecond pulses above and below the critical angle

Author

Chalupsky, J., Hajkova, V., Altapova, V., Burian, T., Gleeson, A.J., Juha, L., Jurek, M., Sinn, H.Stoermer, M., Sobierajski, R., Tiedtke, K., Toleikis, S., Tschentscher, T., Vysin, L., Wabnitz, H., and Gaudin, J.

Abstract

We present results of damage studies conducted at the Free Electron LASer in Hamburg (FLASH) facility with 13.5 nm (91.8 eV) and 7 nm (177.1 eV) radiations. The laser beam was focused on a sample of 890-nm-thick amorphous carbon coated on a silicon wafer mimicking a x-ray mirror. The fluence threshold for graphitization was determined for different grazing angles above and below the critical angle. The observed angular dependence of Fth is explained by the variation in absorption depth and reflectivity. Moreover, the absorbed local dose needed for the phase transition leading to graphitization is shown to vary with the radiation wavelength.

Published
2009
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67. Ablation of single-crystalline cesium iodide by extreme ultraviolet capillary-discharge laser

Author

Wild Jan, Pira Peter, Burian Tomas, Vysin Ludek, Juha Libor, Zelinger Zdenek, Danis Stanislav, Nehasil Vaclav, Rafaj Zdenek, Nevrly Vaclav, Dostal Michal, Bitala Petr, Kudrna Pavel, Tichy Milan, and Rocca Jorge J.

Subjects
ablation, csi, desorption, laser, pld, xuv, Science
Abstract

Extreme ultraviolet (XUV) capillary-discharge lasers (CDLs) are a suitable source for the efficient, clean ablation of ionic crystals, which are obviously difficult to ablate with conventional, long-wavelength lasers. In the present study, a single crystal of cesium iodide (CsI) was irradiated by multiple, focused 1.5-ns pulses of 46.9-nm radiation delivered from a compact XUV-CDL device operated at either 2-Hz or 3-Hz repetition rates. The ablation rates were determined from the depth of the craters produced by the accumulation of laser pulses. Langmuir probes were used to diagnose the plasma plume produced by the focused XUV-CDL beam. Both the electron density and electron temperature were sufficiently high to confirm that ablation was the key process in the observed CsI removal. Moreover, a CsI thin film on MgO substrate was prepared by XUV pulsed laser deposition; a fraction of the film was detected by X-ray photoelectron spectroscopy.

Published
2020
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68. X-ray laser-induced ablation of lead compounds

Author

Hajkova, V., Juha, L., Bohacek, P., Burian, T., Chalupsky, J., Vysin, L., Gaudin, J., Heimann, P. A., Hau-Riege, S. P., Jurek, M., Klinger, D., Pelka, J., Sobierajski, R., Krzywinski, J., Messerschmidt, M., Moeller, S. P., Nagler, B., Rowen, M., Schlotter, W. F., Swiggers, M. L., Turner, J. J., Vinko, S. M., Whitcher, T., Wark, J., Matuchova, M., Bajt, S., Chapman, H., Dzelzainis, T., Riley, D., Andreasson, J., Hajdu, J., Iwan, B., Timneanu, N., Saksl, K., Faeustlin, R., Singer, A., Tiedtke, K., Toleikis, S., Vartaniants, I., Wabnitz, H., Hajkova, V., Juha, L., Bohacek, P., Burian, T., Chalupsky, J., Vysin, L., Gaudin, J., Heimann, P. A., Hau-Riege, S. P., Jurek, M., Klinger, D., Pelka, J., Sobierajski, R., Krzywinski, J., Messerschmidt, M., Moeller, S. P., Nagler, B., Rowen, M., Schlotter, W. F., Swiggers, M. L., Turner, J. J., Vinko, S. M., Whitcher, T., Wark, J., Matuchova, M., Bajt, S., Chapman, H., Dzelzainis, T., Riley, D., Andreasson, J., Hajdu, J., Iwan, B., Timneanu, N., Saksl, K., Faeustlin, R., Singer, A., Tiedtke, K., Toleikis, S., Vartaniants, I., and Wabnitz, H.

Abstract

The recent commissioning of a X-ray free-electron laser triggered an extensive research in the area of X-ray ablation of high-Z, high-density materials. Such compounds should be used to shorten an effective attenuation length for obtaining clean ablation imprints required for the focused beam analysis. Compounds of lead (Z=82) represent the materials of first choice. In this contribution, single-shot ablation thresholds are reported for PbWO(4) and PbI(2) exposed to ultra-short pulses of extreme ultraviolet radiation and X-rays at FLASH and LCLS facilities, respectively. Interestingly, the threshold reaches only 0.11 J/cm(2) at 1.55 nm in lead tungstate although a value of 0.4 J/cm(2) is expected according to the wavelength dependence of an attenuation length and the threshold value determined in the XUV spectral region, i.e., 79 mJ/cm(2) at a FEL wavelength of 13.5 nm. Mechanisms of ablation processes are discussed to explain this discrepancy. Lead iodide shows at 1.55 nm significantly lower ablation threshold than tungstate although an attenuation length of the radiation is in both materials quite the same. Lower thermal and radiation stability of PbI(2) is responsible for this finding., Conference on Damage to VUV, EUV, and X-ray Optics III, Prague, CZECH REPUBLIC, APR 18-20, 2011

Published
2011
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69. Electronic Structure of an XUV Photogenerated Solid-Density Aluminum Plasma

Author

Vinko, S. M., Zastrau, U., Mazevet, S., Andreasson, Jakob, Bajt, S., Burian, T., Chalupsky, J., Chapman, H. N., Cihelka, J., Doria, D., Doeppner, T., Duesterer, S., Dzelzainis, T., Faeustlin, R. R., Fortmann, C., Foerster, E., Galtier, E., Glenzer, S. H., Goede, S., Gregori, G., Hajdu, Janos, Hajkova, V., Heimann, P. A., Irsig, R., Juha, L., Jurek, M., Krzywinski, J., Laarmann, T., Lee, H. J., Lee, R. W., Li, B., Meiwes-Broer, K. -H, Mithen, J. P., Nagler, B., Nelson, A. J., Przystawik, A., Redmer, R., Riley, D., Rosmej, F., Sobierajski, R., Tavella, F., Thiele, R., Tiggesbaeumker, J., Toleikis, S., Tschentscher, T., Vysin, L., Whitcher, T. J., White, S., Wark, J. S., Vinko, S. M., Zastrau, U., Mazevet, S., Andreasson, Jakob, Bajt, S., Burian, T., Chalupsky, J., Chapman, H. N., Cihelka, J., Doria, D., Doeppner, T., Duesterer, S., Dzelzainis, T., Faeustlin, R. R., Fortmann, C., Foerster, E., Galtier, E., Glenzer, S. H., Goede, S., Gregori, G., Hajdu, Janos, Hajkova, V., Heimann, P. A., Irsig, R., Juha, L., Jurek, M., Krzywinski, J., Laarmann, T., Lee, H. J., Lee, R. W., Li, B., Meiwes-Broer, K. -H, Mithen, J. P., Nagler, B., Nelson, A. J., Przystawik, A., Redmer, R., Riley, D., Rosmej, F., Sobierajski, R., Tavella, F., Thiele, R., Tiggesbaeumker, J., Toleikis, S., Tschentscher, T., Vysin, L., Whitcher, T. J., White, S., and Wark, J. S.

Abstract

By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.

Published
2010
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70. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

Author

Nelson, A. J., Toleikis, S., Chapman, H., Bajt, S., Krzywinski, J., Chalupsky, J., Juha, L., Cihelka, J., Hajkova, V., Vysin, L., Burian, T., Kozlova, M., Fäustlin, R. R., Nagler, B., Vinko, S. M., Whitcher, T., Dzelzainis, T., Renner, O., Saksl, K., Khorsand, A. R., Heimann, P. A., Sobierajski, R., Klinger, D., Jurek, M., Pelka, J., Iwan, Bianca, Andreasson, Jakob, Timneanu, Nicusor, Fajardo, M., Wark, J. S., Riley, D., Tschentscher, T., Hajdu, Janos, Lee, R. W., Nelson, A. J., Toleikis, S., Chapman, H., Bajt, S., Krzywinski, J., Chalupsky, J., Juha, L., Cihelka, J., Hajkova, V., Vysin, L., Burian, T., Kozlova, M., Fäustlin, R. R., Nagler, B., Vinko, S. M., Whitcher, T., Dzelzainis, T., Renner, O., Saksl, K., Khorsand, A. R., Heimann, P. A., Sobierajski, R., Klinger, D., Jurek, M., Pelka, J., Iwan, Bianca, Andreasson, Jakob, Timneanu, Nicusor, Fajardo, M., Wark, J. S., Riley, D., Tschentscher, T., Hajdu, Janos, and Lee, R. W.

Abstract

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) -PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of <= 1 mu m. Observations were correlated with simulations of best focus to provide further relevant information.

Published
2009
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71. Photon energy dependence of graphitization threshold for diamond irradiated with an intense XUV FEL pulse

Author

Gaudin, J., primary, Medvedev, N., additional, Chalupský, J., additional, Burian, T., additional, Dastjani-Farahani, S., additional, Hájková, V., additional, Harmand, M., additional, Jeschke, H. O., additional, Juha, L., additional, Jurek, M., additional, Klinger, D., additional, Krzywinski, J., additional, Loch, R. A., additional, Moeller, S., additional, Nagasono, M., additional, Ozkan, C., additional, Saksl, K., additional, Sinn, H., additional, Sobierajski, R., additional, Sovák, P., additional, Toleikis, S., additional, Tiedtke, K., additional, Toufarová, M., additional, Tschentscher, T., additional, Vorlíček, V., additional, Vyšín, L., additional, Wabnitz, H., additional, and Ziaja, B., additional

Published
2013
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72. Experimental set-up and procedures for the investigation of XUV free electron laser interactions with solids

Author

Sobierajski, R, primary, Jurek, M, additional, Chalupský, J, additional, Krzywinski, J, additional, Burian, T, additional, Farahani, S Dastjani, additional, Hájková, V, additional, Harmand, M, additional, Juha, L, additional, Klinger, D, additional, Loch, R A, additional, Ozkan, C, additional, Pełka, J B, additional, Sokolowski-Tinten, K, additional, Sinn, H, additional, Toleikis, S, additional, Tiedtke, K, additional, Tschentscher, T, additional, Wabnitz, H, additional, and Gaudin, J, additional

Published
2013
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73. ResonantKαSpectroscopy of Solid-Density Aluminum Plasmas

Author

Cho, B. I., primary, Engelhorn, K., additional, Vinko, S. M., additional, Chung, H.-K., additional, Ciricosta, O., additional, Rackstraw, D. S., additional, Falcone, R. W., additional, Brown, C. R. D., additional, Burian, T., additional, Chalupský, J., additional, Graves, C., additional, Hájková, V., additional, Higginbotham, A., additional, Juha, L., additional, Krzywinski, J., additional, Lee, H. J., additional, Messersmidt, M., additional, Murphy, C., additional, Ping, Y., additional, Rohringer, N., additional, Scherz, A., additional, Schlotter, W., additional, Toleikis, S., additional, Turner, J. J., additional, Vysin, L., additional, Wang, T., additional, Wu, B., additional, Zastrau, U., additional, Zhu, D., additional, Lee, R. W., additional, Nagler, B., additional, Wark, J. S., additional, and Heimann, P. A., additional

Published
2012
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74. Direct Measurements of the Ionization Potential Depression in a Dense Plasma

Author

Ciricosta, O., primary, Vinko, S. M., additional, Chung, H.-K., additional, Cho, B.-I., additional, Brown, C. R. D., additional, Burian, T., additional, Chalupský, J., additional, Engelhorn, K., additional, Falcone, R. W., additional, Graves, C., additional, Hájková, V., additional, Higginbotham, A., additional, Juha, L., additional, Krzywinski, J., additional, Lee, H. J., additional, Messerschmidt, M., additional, Murphy, C. D., additional, Ping, Y., additional, Rackstraw, D. S., additional, Scherz, A., additional, Schlotter, W., additional, Toleikis, S., additional, Turner, J. J., additional, Vysin, L., additional, Wang, T., additional, Wu, B., additional, Zastrau, U., additional, Zhu, D., additional, Lee, R. W., additional, Heimann, P., additional, Nagler, B., additional, and Wark, J. S., additional

Published
2012
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75. Amorphous to crystalline phase transition in carbon induced by intense femtosecond x-ray free-electron laser pulses

Author

Gaudin, J., primary, Peyrusse, O., additional, Chalupský, J., additional, Toufarová, M., additional, Vyšín, L., additional, Hájková, V., additional, Sobierajski, R., additional, Burian, T., additional, Dastjani-Farahani, Sh., additional, Graf, A., additional, Amati, M., additional, Gregoratti, L., additional, Hau-Riege, S. P., additional, Hoffmann, G., additional, Juha, L., additional, Krzywinski, J., additional, London, R. A., additional, Moeller, S., additional, Sinn, H., additional, Schorb, S., additional, Störmer, M., additional, Tschentscher, Th., additional, Vorlíček, V., additional, Vu, H., additional, Bozek, J., additional, and Bostedt, C., additional

Published
2012
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76. XUV spectroscopic characterization of warm dense aluminum plasmas generated by the free-electron-laser FLASH

Author

Zastrau, U., primary, Burian, T., additional, Chalupsky, J., additional, Döppner, T., additional, Dzelzainis, T.W.J., additional, Fäustlin, R.R., additional, Fortmann, C., additional, Galtier, E., additional, Glenzer, S.H., additional, Gregori, G., additional, Juha, L., additional, Lee, H.J., additional, Lee, R.W., additional, Lewis, C.L.S., additional, Medvedev, N., additional, Nagler, B., additional, Nelson, A.J., additional, Riley, D., additional, Rosmej, F.B., additional, Toleikis, S., additional, Tschentscher, T., additional, Uschmann, I., additional, Vinko, S.M., additional, Wark, J.S., additional, Whitcher, T., additional, and Förster, E., additional

Published
2012
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77. X-ray laser-induced ablation of lead compounds

Author

Hájková, V., primary, Juha, L., additional, Boháček, P., additional, Burian, T., additional, Chalupský, J., additional, Vyšín, L., additional, Gaudin, J., additional, Heimann, P. A., additional, Hau-Riege, S. P., additional, Jurek, M., additional, Klinger, D., additional, Pelka, J., additional, Sobierajski, R., additional, Krzywinski, J., additional, Messerschmidt, M., additional, Moeller, S. P., additional, Nagler, B., additional, Rowen, M., additional, Schlotter, W. F., additional, Swiggers, M. L., additional, Turner, J. J., additional, Vinko, S. M., additional, Whitcher, T., additional, Wark, J., additional, Matuchová, M., additional, Bajt, S., additional, Chapman, H., additional, Dzelzainis, T., additional, Riley, D., additional, Andreasson, J., additional, Hajdu, J., additional, Iwan, B., additional, Timneanu, N., additional, Saksl, K., additional, Fäustlin, R., additional, Singer, A., additional, Tiedtke, K., additional, Toleikis, S., additional, Vartaniants, I., additional, and Wabnitz, H., additional

Published
2011
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79. Damage threshold of amorphous carbon mirror for 177eV FEL radiation

Author

Dastjani Farahani, Sh., primary, Chalupsky, Jaromir, additional, Burian, T., additional, Chapman, Henry, additional, Gleeson, A.J., additional, Hajkoya, V., additional, Juha, L., additional, Jurek, M., additional, Klinger, Dorota, additional, Sinn, Harald, additional, Sobierajski, R., additional, Störmer, M., additional, Tiedtke, K., additional, Toleikis, S., additional, Tschentscher, Thomas, additional, Wabnitz, H., additional, and Gaudin, Jerome, additional

Published
2011
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80. Damage mechanisms of MoN/SiN multilayer optics for next-generation pulsed XUV light sources

Author

Sobierajski, R., primary, Bruijn, S., additional, Khorsand, A.R., additional, Louis, E., additional, van de Kruijs, R.W. E., additional, Burian, T., additional, Chalupsky, J., additional, Cihelka, J., additional, Gleeson, A., additional, Grzonka, J., additional, Gullikson, E.M., additional, Hajkova, V., additional, Hau-Riege, S., additional, Juha, L., additional, Jurek, M., additional, Klinger, D., additional, Krzywinski, J., additional, London, R., additional, Pelka, J. B., additional, Płociński, T., additional, Rasiński, M., additional, Tiedtke, K., additional, Toleikis, S., additional, Vysin, L., additional, Wabnitz, H., additional, and Bijkerk, F., additional

Published
2010
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81. Spot size characterization of focused non-Gaussian X-ray laser beams

Author

Chalupský, J., primary, Krzywinski, J., additional, Juha, L., additional, Hájková, V., additional, Cihelka, J., additional, Burian, T., additional, Vyšín, L., additional, Gaudin, J., additional, Gleeson, A., additional, Jurek, M., additional, Khorsand, A. R., additional, Klinger, D., additional, Wabnitz, H., additional, Sobierajski, R., additional, Störmer, M., additional, Tiedtke, K., additional, and Toleikis, S., additional

Published
2010
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82. Interaction of short x-ray pulses with low-Z x-ray optics materials at the LCLS free-electron laser

Author

Hau-Riege, S. P., primary, London, R. A., additional, Graf, A., additional, Baker, S. L., additional, Soufli, R., additional, Sobierajski, R., additional, Burian, T., additional, Chalupsky, J., additional, Juha, L., additional, Gaudin, J., additional, Krzywinski, J., additional, Moeller, S., additional, Messerschmidt, M., additional, Bozek, J., additional, and Bostedt, C., additional

Published
2010
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83. Electronic Structure of an XUV Photogenerated Solid-Density Aluminum Plasma

Author

Vinko, S. M., primary, Zastrau, U., additional, Mazevet, S., additional, Andreasson, J., additional, Bajt, S., additional, Burian, T., additional, Chalupsky, J., additional, Chapman, H. N., additional, Cihelka, J., additional, Doria, D., additional, Döppner, T., additional, Düsterer, S., additional, Dzelzainis, T., additional, Fäustlin, R. R., additional, Fortmann, C., additional, Förster, E., additional, Galtier, E., additional, Glenzer, S. H., additional, Göde, S., additional, Gregori, G., additional, Hajdu, J., additional, Hajkova, V., additional, Heimann, P. A., additional, Irsig, R., additional, Juha, L., additional, Jurek, M., additional, Krzywinski, J., additional, Laarmann, T., additional, Lee, H. J., additional, Lee, R. W., additional, Li, B., additional, Meiwes-Broer, K.-H., additional, Mithen, J. P., additional, Nagler, B., additional, Nelson, A. J., additional, Przystawik, A., additional, Redmer, R., additional, Riley, D., additional, Rosmej, F., additional, Sobierajski, R., additional, Tavella, F., additional, Thiele, R., additional, Tiggesbäumker, J., additional, Toleikis, S., additional, Tschentscher, T., additional, Vysin, L., additional, Whitcher, T. J., additional, White, S., additional, and Wark, J. S., additional

Published
2010
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84. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

Author

Nelson, A. J., primary, Toleikis, S., additional, Chapman, H., additional, Bajt, S., additional, Krzywinski, J., additional, Chalupsky, J., additional, Juha, L., additional, Cihelka, J., additional, Hajkova, V., additional, Vysin, L., additional, Burian, T., additional, Kozlova, M., additional, Fäustlin, R.R., additional, Nagler, B., additional, Vinko, S.M., additional, Whitcher, T., additional, Dzelzainis, T., additional, Renner, O., additional, Saksl, K., additional, Khorsand, A. R., additional, Heimann, P. A., additional, Sobierajski, R., additional, Klinger, D., additional, Jurek, M., additional, Pelka, J., additional, Iwan, B., additional, Andreasson, J., additional, Timneanu, N., additional, Fajardo, M., additional, Wark, J.S., additional, Riley, D., additional, Tschentscher, T., additional, Hajdu, J., additional, and Lee, R. W., additional

Published
2009
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85. Perspective for high energy density studies on x-ray FELs

Author

Lee, R. W., primary, Nagler, B., additional, Zastrau, U., additional, Fäustlin, R., additional, Vinko, S. M., additional, Whitcher, T., additional, Sobierajski, R., additional, Krzywinski, J., additional, Juha, L., additional, Nelson, A. J., additional, Bajt, S., additional, Budil, K., additional, Cauble, R. C., additional, Bornath, T., additional, Burian, T., additional, Chalupsky, J., additional, Chapman, H., additional, Cihelka, J., additional, Döppner, T., additional, Dzelzainis, T., additional, Düsterer, S., additional, Fajardo, M., additional, Förster, E., additional, Fortmann, C., additional, Glenzer, S. H., additional, Göde, S., additional, Gregori, G., additional, Hajkova, V., additional, Heimann, P., additional, Jurek, M., additional, Khattak, F. Y., additional, Khorsand, A. R., additional, Klinger, D., additional, Kozlova, M., additional, Laarmann, T., additional, Lee, H.-J., additional, Meiwes-Broer, K.-H., additional, Mercere, P., additional, Murphy, W. J., additional, Przystawik, A., additional, Redmer, R., additional, Reinholz, H., additional, Riley, D., additional, Röpke, G., additional, Saksl, K., additional, Thiele, R., additional, Tiggesbäumker, J., additional, Toleikis, S., additional, Tschentscher, T., additional, Uschmann, I., additional, Falcone, R. W., additional, Shepherd, R., additional, Hastings, J. B., additional, White, W. E., additional, and Wark, J. S., additional

Published
2009
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86. Perspective for high energy density studies using x-ray free electron lasers

Author

Lee, R. W., primary, Nagler, B., additional, Zastrau, U., additional, Faustlin, R., additional, Vinko, S., additional, Whitcher, T., additional, Sobierajski, R., additional, Krzywinski, J., additional, Juha, L., additional, Nelson, A., additional, Bajt, S., additional, Bornath, T., additional, Burian, T., additional, Chalupsky, J., additional, Chapman, H., additional, Cihelka, J., additional, Doppner, T., additional, Dzelzainis, T., additional, Dusterer, S., additional, Fajardo, M., additional, Forster, E., additional, Fortmann, C., additional, Glenzer, S. H., additional, Gode, S., additional, Gregori, G., additional, Hajkova, V., additional, Heimann, P., additional, Jurek, M., additional, Khattak, F., additional, Khorsand, A. R., additional, Klinger, D., additional, Kozlova, M., additional, Laarmann, T., additional, Lee, H., additional, Meiwes-Broer, K., additional, Mercere, P., additional, Murphy, W. J., additional, Przystawik, A., additional, Redmer, R., additional, Reinholz, H., additional, Riley, D., additional, Ropke, G., additional, Saksl, K., additional, Thiele, R., additional, Tiggesbaumker, J., additional, Toleikis, S., additional, Tschentscher, T., additional, Uschmann, I., additional, and Wark, J. S., additional

Published
2009
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88. Perspective for high energy density studies on x-ray FELs.

Author

Lee, R. W., Nagler, B., Zastrau, U., Fäustlin, R., Vinko, S. M., Whitcher, T., Sobierajski, R., Krzywinski, J., Juha, L., Nelson, A. J., Bajt, S., Budil, K., Cauble, R. C., Bornath, T., Burian, T., Chalupsky, J., Chapman, H., Cihelka, J., Döppner, T., and Dzelzainis, T.

Published
2009
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89. Comparative damage studies in multilayer optics induced by intense short-wavelength pulses from FLSH and LCLS

Author

Loch, R. A., Sobierajski, R., Bostedt, C., Bruijn, S., Burian, T., Chalupsky, J., Feng, Y. C., Gaudin, J., Graf, A., Hattum, E. D., Hau-Riege, S., Juha, L., Khorsand, A. R., Klinger, D., Robbert van de Kruijs, Krzywinski, J., London, R., Eric Louis, Messerschmidt, M., Moeller, S., Schlotter, W., Tiedtke, K., Frederik Bijkerk, and Laser Physics & Nonlinear Optics

Subjects
METIS-277884

90. Investigation of spontaneous magnetic fields, electron and ion emission in laser-produced plasma experiments at PALS

Author

Pisarczyk, T., Gus Kov, S. Yu, Batani, D., Dudzak, R., Zaras-Szydlowska, A., Chodukowski, T., Rusiniak, Z., Jan Dostal, Renner, O., Demchenko, N. N., Singh, S., Korneev, Ph, Burian, T., Makaruk, D., Rosinski, M., Krupka, M., Pfeifer, M., Cikhardt, J., Krasa, J., Cristoforetti, G., Antonelli, L., Kalal, M., Borodziuk, S., Krus, M., Juha, L., Kochetkov, J., Hrebicek, J., Golasowski, J., Baffigi, F., Filippov, E. D., Gizzi, L. A., Volpe, L., Trela, J., Malko, S., Mancelli, D., Martynenko, A. S., Turianska, O., Ospina, V., Tentori, A., and Skala, J.

91. FEL multilayer optics damaged by multiple shot laser beam: experimental results and discussion

Author

Giglia, A., Mahne, N., Bianco, A., Svetina, C., Cucini, R., Vysin, L., Burian, T., Juha, L., and Nannarone, S.

Abstract

The irradiation effects of multiple ultrafast shots of laser beams with estimated fluences of some tens of mJ/cm2on a EUV Mo/Si multilayer have been studied. Irradiation damage has been induced by multiple shots of two different lasers (100 fs 400 nm the first, 1.5 ns 46.9 nm the second). The study has been motivated by the need of multilayer Mo/Si optics for the delay lines of the FEL source FERMI@Elettra, where these mirrors will be used to reflect 100 fs pulses at 13 nm with a fluence of some mJ/cm2. The analysis has been performed by means of different techniques as EUV and soft X-ray reflectivity, XPS, and Standing wave enhanced XPS. Simulations have been carried on by means of an indigenously developed software OPAL (Optical Properties of Anisotropic Layers) for the calculation of the absorbed energy by the stratified medium. AFM and SEM surface images have been also acquired. In the irradiation at 400 nm, we observed a significant change in the multilayer performance at fluences of 100 mJ/cm2and above with a significant reduction of reflectivity. Spectroscopic analysis allowed to correlate the decrease of reflectivity with the degradation of the multilayer stacking, ascribed to Mo-Si intermixing at the Mo/Si interfaces of the first few layers, close to the surface of the mirror. Preliminary tests have been also performed on the sample irradiated at 46.9 nm.

Published
2011
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92. Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument

Author

Sergey Makarov, Mikako Makita, Motoaki Nakatsutsumi, Tatiana Pikuz, Norimasa Ozaki, Thomas R. Preston, Karen Appel, Zuzana Konopkova, Valerio Cerantola, Erik Brambrink, Jan-Patrick Schwinkendorf, Istvan Mohacsi, Tomas Burian, Jaromir Chalupsky, Vera Hajkova, Libor Juha, Vojtech Vozda, Bob Nagler, Ulf Zastrau, Sergey Pikuz, Makarov, S, Makita, M, Nakatsutsumi, M, Pikuz, T, Ozaki, N, Preston, T, Appel, K, Konopkova, Z, Cerantola, V, Brambrink, E, Schwinkendorf, J, Mohacsi, I, Burian, T, Chalupsky, J, Hajkova, V, Juha, L, Vozda, V, Nagler, B, Zastrau, U, and Pikuz, S

Subjects
Nuclear and High Energy Physics, Radiation, X-ray beam characterization, X-ray free-electron laser, lithium fluoride (LiF) detector, Instrumentation, compound refractive lense, focusing system, X-ray focusing
Abstract

The application of fluorescent crystal media in wide-range X-ray detectors provides an opportunity to directly image the spatial distribution of ultra-intense X-ray beams including investigation of the focal spot of free-electron lasers. Here the capabilities of the micro- and nano-focusing X-ray refractive optics available at the High Energy Density instrument of the European XFEL are reported, as measured in situ by means of a LiF fluorescent detector placed into and around the beam caustic. The intensity distribution of the beam focused down to several hundred nanometers was imaged at 9 keV photon energy. A deviation from the parabolic surface in a stack of nanofocusing Be compound refractive lenses (CRLs) was found to affect the resulting intensity distribution within the beam. Comparison of experimental patterns in the far field with patterns calculated for different CRL lens imperfections allowed the overall inhomogeneity in the CRL stack to be estimated. The precise determination of the focal spot size and shape on a sub-micrometer level is essential for a number of high energy density studies requiring either a pin-size backlighting spot or extreme intensities for X-ray heating.

Published
2023

93. Imaging x-ray spectrometer at the high energy density instrument of the European x-ray free electron laser

Author

X. Pan, M. Šmíd, R. Štefaníková, F. Donat, C. Baehtz, T. Burian, V. Cerantola, L. Gaus, O. S. Humphries, V. Hajkova, L. Juha, M. Krupka, M. Kozlová, Z. Konopkova, T. R. Preston, L. Wollenweber, U. Zastrau, K. Falk, Pan, X, Smid, M, Stefanikova, R, Donat, F, Baehtz, C, Burian, T, Cerantola, V, Gaus, L, Humphries, O, Hajkova, V, Juha, L, Krupka, M, Kozlova, M, Konopkova, Z, Preston, T, Wollenweber, L, Zastrau, U, and Falk, K

Subjects
FEL, spectrometer, XES, IXS, XAS, Instrumentation
Abstract

A multipurpose imaging x-ray crystal spectrometer is developed for the high energy density instrument of the European X-ray Free Electron Laser. The spectrometer is designed to measure x rays in the energy range of 4–10 keV, providing high-resolution, spatially resolved spectral measurements. A toroidally bent germanium (Ge) crystal is used, allowing x-ray diffraction from the crystal to image along a one-dimensional spatial profile while spectrally resolving along the other. A detailed geometrical analysis is performed to determine the curvature of the crystal. The theoretical performance of the spectrometer in various configurations is calculated by ray-tracing simulations. The key properties of the spectrometer, including the spectral and spatial resolution, are demonstrated experimentally on different platforms. Experimental results prove that this Ge spectrometer is a powerful tool for spatially resolved measurements of x-ray emission, scattering, or absorption spectra in high energy density physics.

Published
2023
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94. Resonant Ka Spectroscopy of Solid-Density Aluminum Plasmas.

Author

Cho, B. I., Engelhorn, K., Vinko, S. M., Chung, H.-K., Ciricosta, O., Rackstraw, D. S., Falcone, R. W., Brown, C. R. D., Burian, T., Chalupsky, J., Graves, C., Hájková, V., Higginbotham, A., Juha, L., Krzywinskj, J., Lee, H. J., Messersmidt, M., Murphy, C., Ping, Y., and Rohringer, N.

Subjects
*X-rays in industry, *FREE electron lasers, *PHOTONS, *PICOSECOND pulses, *ALUMINUM, *PHYSICAL & theoretical chemistry
Abstract

The x-ray intensities made available by x-ray free electron lasers (FEL) open up new x-ray matter interaction channels not accessible with previous sources. We report here on the resonant generation of Ka emission, that is to say the production of copious Ka radiation by tuning the x-ray FEL pulse to photon energies below that of the K edge of a solid aluminum sample. The sequential absorption of multiple photons in the same atom during the 80 fs pulse, with photons creating L-shell holes and then one resonantly exciting a K-shell electron into one of these holes, opens up a channel for the Ka production, as well as the absorption of further photons. We demonstrate rich spectra of such channels, and investigate the emission produced by tuning the FEL energy to the K-L transitions of those highly charged ions that have transition energies below the K edge of the cold material. The spectra are sensitive to x-ray intensity dependent opacity effects, with ions containing L-shell holes readily reabsorbing the Ka radiation. [ABSTRACT FROM AUTHOR]

Published
2012
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95. Comparison of wavefront sensing and ablation imprinting for FEL focus diagnostics at FLASH2.

Author

Keitel B, Chalupský J, Jelínek Š, Burian T, Dziarzhytski S, Hájková V, Juha L, Kuglerová Z, Kuhlmann M, Mann K, Ruiz-Lopez M, Schäfer B, Vozda V, Wodzinski T, Yurkov MV, and Plönjes E

Abstract

Extreme ultraviolet (EUV) photon beam characterization techniques, Hartmann wavefront sensing and single shot ablation imprinting, were compared along the caustic of a tightly focused free-electron laser (FEL) beam at beamline FL24 of FLASH2, the Free-electron LASer in Hamburg at DESY. The transverse coherence of the EUV FEL was determined by a Young's double pinhole experiment and used in a back-propagation algorithm which includes partial coherence to calculate the beam intensity profiles along the caustic from the wavefront measurements. A very good agreement of the profile structure and size is observed for different wavelengths between the back-propagated profiles, an indirect technique, and ablation imprints. As a result, the Hartmann wavefront sensor including its software MrBeam is a very useful, single shot pulse resolved and fast tool for non-invasive determination of focal spot size and shape and also for beam profiles along the caustic.

Published
2024
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96. Damage threshold of LiF crystal irradiated by femtosecond hard XFEL pulse sequence.

Author

Makarov S, Grigoryev S, Inogamov N, Filippov E, Pikuz T, Ozaki N, Ishino M, Nishikino M, Dinh TH, Kawachi T, Zanaveskin M, Makita M, Nakatsutsumi M, Preston TR, Appel K, Konopkova Z, Cerantola V, Brambrink E, Schwinkendorf JP, Mohacsi I, Vozda V, Hajkova V, Burian T, Chalupsky J, Juha L, Zhakhovsky V, Zastrau U, and Pikuz S

Abstract

Here we demonstrate the results of investigating the damage threshold of a LiF crystal after irradiating it with a sequence of coherent femtosecond pulses using the European X-ray Free Electron Laser (EuXFEL). The laser fluxes on the crystal surface varied in the range ∼ 0.015-13 kJ/cm 2 per pulse when irradiated with a sequence of 1-100 pulses (t pulse ∼ 20 fs, E ph  = 9 keV). Analysis of the surface of the irradiated crystal using different reading systems allowed the damage areas and the topology of the craters formed to be accurately determined. It was found that the ablation threshold decreases with increasing number of X-ray pulses, while the depth of the formed craters increases non-linearly and reaches several hundred nanometers. The obtained results have been compared with data already available in the literature for nano- and picosecond pulses from lasers in the soft X-ray/VUV and optical ranges. A failure model of lithium fluoride is developed and verified with simulation of material damage under single-pulse irradiation. The obtained damage threshold is in reasonably good agreement with the experimentally measured one.

Published
2023
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97. Deep learning for laser beam imprinting.

Author

Chalupský J, Vozda V, Hering J, Kybic J, Burian T, Dziarzhytski S, Frantálová K, Hájková V, Jelínek Š, Juha L, Keitel B, Kuglerová Z, Kuhlmann M, Petryshak B, Ruiz-Lopez M, Vyšín L, Wodzinski T, and Plönjes E

Abstract

Methods of ablation imprints in solid targets are widely used to characterize focused X-ray laser beams due to a remarkable dynamic range and resolving power. A detailed description of intense beam profiles is especially important in high-energy-density physics aiming at nonlinear phenomena. Complex interaction experiments require an enormous number of imprints to be created under all desired conditions making the analysis demanding and requiring a huge amount of human work. Here, for the first time, we present ablation imprinting methods assisted by deep learning approaches. Employing a multi-layer convolutional neural network (U-Net) trained on thousands of manually annotated ablation imprints in poly(methyl methacrylate), we characterize a focused beam of beamline FL24/FLASH2 at the Free-electron laser in Hamburg. The performance of the neural network is subject to a thorough benchmark test and comparison with experienced human analysts. Methods presented in this Paper pave the way towards a virtual analyst automatically processing experimental data from start to end.

Published
2023
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98. Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument.

Author

Makarov S, Makita M, Nakatsutsumi M, Pikuz T, Ozaki N, Preston TR, Appel K, Konopkova Z, Cerantola V, Brambrink E, Schwinkendorf JP, Mohacsi I, Burian T, Chalupsky J, Hajkova V, Juha L, Vozda V, Nagler B, Zastrau U, and Pikuz S

Abstract

The application of fluorescent crystal media in wide-range X-ray detectors provides an opportunity to directly image the spatial distribution of ultra-intense X-ray beams including investigation of the focal spot of free-electron lasers. Here the capabilities of the micro- and nano-focusing X-ray refractive optics available at the High Energy Density instrument of the European XFEL are reported, as measured in situ by means of a LiF fluorescent detector placed into and around the beam caustic. The intensity distribution of the beam focused down to several hundred nanometers was imaged at 9 keV photon energy. A deviation from the parabolic surface in a stack of nanofocusing Be compound refractive lenses (CRLs) was found to affect the resulting intensity distribution within the beam. Comparison of experimental patterns in the far field with patterns calculated for different CRL lens imperfections allowed the overall inhomogeneity in the CRL stack to be estimated. The precise determination of the focal spot size and shape on a sub-micrometer level is essential for a number of high energy density studies requiring either a pin-size backlighting spot or extreme intensities for X-ray heating., (open access.)

Published
2023
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99. Real-time spatial characterization of micrometer-sized X-ray free-electron laser beams focused by bendable mirrors.

Author

Mercurio G, Chalupský J, Nistea IT, Schneider M, Hájková V, Gerasimova N, Carley R, Cascella M, Le Guyader L, Mercadier L, Schlappa J, Setoodehnia K, Teichmann M, Yaroslavtsev A, Burian T, Vozda V, Vyšín L, Wild J, Hickin D, Silenzi A, Stupar M, Torben Delitz J, Broers C, Reich A, Pfau B, Eisebitt S, La Civita D, Sinn H, Vannoni M, Alcock SG, Juha L, and Scherz A

Abstract

A real-time and accurate characterization of the X-ray beam size is essential to enable a large variety of different experiments at free-electron laser facilities. Typically, ablative imprints are employed to determine shape and size of µm-focused X-ray beams. The high accuracy of this state-of-the-art method comes at the expense of the time required to perform an ex-situ image analysis. In contrast, diffraction at a curved grating with suitably varying period and orientation forms a magnified image of the X-ray beam, which can be recorded by a 2D pixelated detector providing beam size and pointing jitter in real time. In this manuscript, we compare results obtained with both techniques, address their advantages and limitations, and demonstrate their excellent agreement. We present an extensive characterization of the FEL beam focused to ≈1 µm by two Kirkpatrick-Baez (KB) mirrors, along with optical metrology slope profiles demonstrating their exceptionally high quality. This work provides a systematic and comprehensive study of the accuracy provided by curved gratings in real-time imaging of X-ray beams at a free-electron laser facility. It is applied here to soft X-rays and can be extended to the hard X-ray range. Furthermore, curved gratings, in combination with a suitable detector, can provide spatial properties of µm-focused X-ray beams at MHz repetition rate.

Published
2022
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100. Characterization of megahertz X-ray laser beams by multishot desorption imprints in PMMA.

Author

Vozda V, Burian T, Hájková V, Juha L, Enkisch H, Faatz B, Hermann M, Jacyna I, Jurek M, Keitel B, Klinger D, Loch R, Louis E, Makhotkin IA, Plönjes E, Saksl K, Siewert F, Sobierajski R, Strobel S, Tiedtke K, Toleikis S, de Vries G, Zelinger Z, and Chalupský J

Abstract

Proper diagnostics of intense free-electron laser (FEL) X-ray pulses is indisputably important for experimental data analysis as well as for the protection of beamline optical elements. New challenges for beam diagnostic methods are introduced by modern FEL facilities capable of delivering powerful pulses at megahertz (MHz) repetition rates. In this paper, we report the first characterization of a defocused MHz 13.5-nm beam generated by the free-electron laser in Hamburg (FLASH) using the method of multi-pulse desorption imprints in poly(methyl methacrylate)(PMMA). The beam fluence profile is reconstructed in a novel and highly accurate way that takes into account the nonlinear response of material removal to total dose delivered by multiple pulses. The algorithm is applied to experimental data of single-shot ablation imprints and multi-shot desorption imprints at both low (10 Hz) and high (1 MHz) repetition rates. Reconstructed response functions show a great agreement with the theoretical desorption response function model.

Published
2020
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