8 results on '"Sokaras, D."'
Search Results
2. Hammerhead, an ultrahigh resolution ePix camera for wavelength-dispersive spectrometers
- Author
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Blaj, G., Bhogadi, D., Chang, C. -E., Doering, D., Kenney, C. J., Kroll, T., Kwiatkowski, M., Segal, J., Sokaras, D., and Haller, G.
- Subjects
Physics - Instrumentation and Detectors - Abstract
Wavelength-dispersive spectrometers (WDS) are often used in synchrotron and FEL applications where high energy resolution (in the order of eV) is important. Increasing WDS energy resolution requires increasing spatial resolution of the detectors in the dispersion direction. The common approaches with strip detectors or small pixel detectors are not ideal. We present a novel approach, with a sensor using rectangular pixels with a high aspect ratio (between strips and pixels, further called "strixels"), and strixel redistribution to match the square pixel arrays of typical ASICs while avoiding the considerable effort of redesigning ASICs. This results in a sensor area of 17.4 mm x 77 mm, with a fine pitch of 25 $\mu$m in the horizontal direction resulting in 3072 columns and 176 rows. The sensors use ePix100 readout ASICs, leveraging their low noise (43 e$^-$, or 180 eV rms). We present results obtained with a Hammerhead ePix100 camera, showing that the small pitch (25 $\mu$m) in the dispersion direction maximizes performance for both high and low photon occupancies, resulting in optimal WDS energy resolution. The low noise level at high photon occupancy allows precise photon counting, while at low occupancy, both the energy and the subpixel position can be reconstructed for every photon, allowing an ultrahigh resolution (in the order of 1 $\mu$m) in the dispersion direction and rejection of scattered beam and harmonics. Using strixel sensors with redistribution and flip-chip bonding to standard ePix readout ASICs results in ultrahigh position resolution ($\sim$1 $\mu$m) and low noise in WDS applications, leveraging the advantages of hybrid pixel detectors (high production yield, good availability, relatively inexpensive) while minimizing development complexity through sharing the ASIC, hardware, software and DAQ development with existing versions of ePix cameras., Comment: 8 pages, 6 figures
- Published
- 2019
- Full Text
- View/download PDF
3. Abbreviated Technical Report: Experimentally Interrogating Detonation Chemistry on Sub-Nanosecond to Nanosecond Timescales
- Author
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Willey, T, primary, Paredes-Mellone, O, additional, Nielsen, M, additional, Sokaras, D, additional, Hammons, J, additional, Ebrahim, A, additional, and Taylor, G, additional
- Published
- 2023
- Full Text
- View/download PDF
4. Probing 5f-state configurations in URu2Si2 with U L3-edge resonant x-ray emission spectroscopy
- Author
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Booth, C. H., Medling, S. A., Tobin, J. G., Baumbach, R. E., Bauer, E. D., Sokaras, D., Nordlund, D., and Weng, T. -C.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Resonant x-ray emission spectroscopy (RXES) was employed at the U L3 absorption edge and the La1 emission line to explore the 5f occupancy, nf, and the degree of 5f orbital delocalization in the hidden order compound URu2Si2. By comparing to suitable reference materials such as UF4, UCd11, and alpha-U, we conclude that the 5f orbital in URu2Si2 is at least partially delocalized with nf = 2.87 +/- 0.08, and does not change with temperature down to 10 K within the estimated error. These results place further constraints on theoretical explanations of the hidden order, especially those requiring a localized f2 ground state., Comment: 11 pages,7 figures
- Published
- 2016
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5. Ultrafast THz Field Control of Electronic and Structural Interactions in Vanadium Dioxide
- Author
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Gray, A. X., Hoffmann, M. C., Jeong, J., Aetukuri, N. P., Zhu, D., Hwang, H. Y., Brandt, N. C., Wen, H., Sternbach, A. J., Bonetti, S., Reid, A. H., Kukreja, R., Graves, C., Wang, T., Granitzka, P., Chen, Z., Higley, D. J., Chase, T., Jal, E., Abreu, E., Liu, M. K., Weng, T. -C., Sokaras, D., Nordlund, D., Chollet, M., Lemke, H., Glownia, J., Trigo, M., Zhu, Y., Ohldag, H., Freeland, J. W., Samant, M. G., Berakdar, J., Averitt, R. D., Nelson, K. A., Parkin, S. S. P., and Dürr, H. A.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Vanadium dioxide, an archetypal correlated-electron material, undergoes an insulator-metal transition near room temperature that exhibits electron-correlation-driven and structurally-driven physics. Using ultrafast optical spectroscopy and x-ray scattering we show that these processes can be disentangled in the time domain. Specifically, following intense sub-picosecond electric-field excitation, a partial collapse of the insulating gap occurs within the first ps. Subsequently, this electronic reconfiguration initiates a change in lattice symmetry taking place on a slower timescale. We identify the kinetic energy increase of electrons tunneling in the strong electric field as the driving force, illustrating a novel method to control electronic interactions in correlated materials on an ultrafast timescale.
- Published
- 2016
- Full Text
- View/download PDF
6. Multiconfigurational nature of 5f orbitals in uranium and plutonium intermetallics
- Author
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Booth, C. H., Jiang, Yu, Wang, D. L., Mitchell, J. N., Tobash, P. H., Bauer, E. D., Wall, M. A., Allen, P. G., Sokaras, D., Nordlund, D., Weng, T. -C., Torrez, M. A., and Sarrao, J. L.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Uranium and plutonium's 5f electrons are tenuously poised between strongly bonding with ligand spd-states and residing close to the nucleus. The unusual properties of these elements and their compounds (eg. the six different allotropes of elemental plutonium) are widely believed to depend on the related attributes of f-orbital occupancy and delocalization, for which a quantitative measure is lacking. By employing resonant x-ray emission spectroscopy (RXES) and x-ray absorption near-edge structure (XANES) spectroscopy and making comparisons to specific heat measurements, we demonstrate the presence of multiconfigurational f-orbital states in the actinide elements U and Pu, and in a wide range of uranium and plutonium intermetallic compounds. These results provide a robust experimental basis for a new framework for understanding the strongly-correlated behavior of actinide materials., Comment: 30 pages, concatenated article and supporting information, 10 figures
- Published
- 2012
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7. Probing the f-state configuration of URu2Si2 with U LIII-edge resonant x-ray absorption spectroscopy
- Author
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Medling, S., primary, Booth, C., additional, Tobin, J., additional, Baumbach, R., additional, Bauer, E., additional, Sokaras, D., additional, Nordlund, D., additional, and Weng, T., additional
- Published
- 2015
- Full Text
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8. New Science Opportunities Enabled by LCLS-II X-Ray Lasers
- Author
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Abbamonte, P., primary, Abild-Pedersen, Frank, additional, Adams, P., additional, Ahmed, M., additional, Albert, F., additional, Mori, R., additional, Anfinrud, P., additional, Aquila, A., additional, Armstrong, M., additional, Arthur, J., additional, Bargar, J., additional, Barty, A., additional, Bergmann, U., additional, Berrah, N., additional, Blaj, G., additional, Bluhm, H., additional, Bolme, C., additional, Bostedt, C., additional, Boutet, S., additional, Brown, G., additional, Bucksbaum, P., additional, Cargnello, M., additional, Carini, G., additional, Cavalleri, A., additional, Cherezov, V., additional, Chiu, W., additional, Chuang, Y., additional, Cocco, D., additional, Coffee, R., additional, Collins, G., additional, Cordones-Hahn, A., additional, Cryan, J., additional, Dakovski, G., additional, Dantus, M., additional, Demirci, H., additional, Denes, P., additional, Devereaux, T., additional, Ding, Y., additional, Doniach, S., additional, Dorner, R., additional, Dunne, M., additional, Durr, H., additional, Egami, T., additional, Eisenberg, D., additional, Emma, P., additional, Fadley, C., additional, Falcone, R., additional, Feng, Y., additional, Fischer, P., additional, Fiuza, F., additional, Fletcher, L., additional, Foucar, L., additional, Frank, M., additional, Fraser, J., additional, Frei, H., additional, Fritz, D., additional, Fromme, P., additional, Fry, A., additional, Fuchs, M., additional, Fuoss, P., additional, Gaffney, K., additional, Gamboa, E., additional, Gessner, O., additional, Ghimire, S., additional, Gleason, A., additional, Glenzer, S., additional, Gorkhover, T., additional, Gray, A., additional, Guehr, M., additional, Guo, J., additional, Hajdu, J., additional, Hansen, S., additional, Hart, P., additional, Hashimoto, M., additional, Hastings, J., additional, Haxton, D., additional, Heimann, P., additional, Heinz, T., additional, Hexemer, A., additional, Hill, J., additional, Himpsel, F., additional, Ho, P., additional, Hogue, B., additional, Huang, Z., additional, Hunter, M., additional, Hura, G., additional, Huse, N., additional, Hussain, Z., additional, Ilchen, M., additional, Jacobsen, C., additional, Kenney, C., additional, Kern, J., additional, Kevan, S., additional, Kim, J., additional, Kim, H., additional, Kirchmann, P., additional, Kirian, R., additional, Kivelson, S., additional, Kliewer, C., additional, Koralek, J., additional, Kovacsova, G., additional, Lanzara, A., additional, LaRue, J., additional, Lee, H., additional, Lee, J., additional, Lee, W., additional, Lee, Y., additional, Lindau, I., additional, Lindenberg, A., additional, Liu, Z., additional, Lu, D., additional, Lundstrom, U., additional, MacDowell, A., additional, Mao, W., additional, Marangos, J., additional, Marcus, G., additional, Martinez, T., additional, McCurdy, W., additional, McDermott, G., additional, McGuffey, C., additional, Minitti, M., additional, Miyabe, S., additional, Moeller, S., additional, Moore, R., additional, Mukamel, S., additional, Nass, K., additional, Natan, A., additional, Nelson, K., additional, Nemsak, S., additional, Neumark, D., additional, Neutze, R., additional, Nilsson, A., additional, Nordlund, D., additional, Norskov, J., additional, Nozawa, S., additional, Ogasawara, H., additional, Ohldag, H., additional, Orville, A., additional, Osborn, D., additional, Osipov, T., additional, Ourmazd, A., additional, Parkinson, D., additional, Pellegrini, C., additional, Phillips, G., additional, Rasing, T., additional, Raubenheimer, T., additional, Recigno, T., additional, Reid, A., additional, Reis, D., additional, Robert, A., additional, Robinson, J., additional, Rolles, D., additional, Rost, J., additional, Roy, S., additional, Rudenko, A., additional, Russell, T., additional, Sandberg, R., additional, Sandhu, A., additional, Sauter, N., additional, Schlichting, I., additional, Schlogl, R., additional, Schlotter, W., additional, Schmidt, M., additional, Schneider, J., additional, Schoenlein, R., additional, Schoeffler, M., additional, Scholl, A., additional, Shen, Z., additional, Shpyrko, O., additional, Silva, T., additional, Sinha, S., additional, Slaughter, D., additional, Sobota, J., additional, Sokaras, D., additional, Sokolowski-Tinten, K., additional, Southworth, S., additional, Spence, J., additional, Stan, C., additional, Stohr, J., additional, Stroud, R., additional, Sundstrom, V., additional, Taatjes, C., additional, Thomas, A., additional, Trigo, M., additional, Tsui, Y., additional, Turner, J., additional, van Buuren, A., additional, Vinko, S., additional, Wakatsuki, S., additional, Wark, J., additional, Weber, P., additional, Weber, T., additional, Wei, M., additional, Weiss, T., additional, Wernet, P., additional, White, W., additional, Willmott, P., additional, Wilson, K., additional, Wurth, W., additional, Yachandra, V., additional, Yano, J., additional, Yarotski, D., additional, Young, L., additional, Zhu, Y., additional, Zhu, D., additional, and Zwart, P., additional
- Published
- 2015
- Full Text
- View/download PDF
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