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2. What Even Is Gender?

Author

Briggs, R. A. and George, B. R.

Subjects
ethics, feminism, gender, identity, sex, trans
Abstract

Debates about gender are everywhere. Is it an inner identity, a biological fact, or an oppressive system? Should we respect it or resist it? What Even Is Gender? shifts the conversation in a fresh direction, arguing that these debates rest on a shared mistake: the idea that there is one thing called "gender" that both sides are arguing about. The authors distinguish a range of phenomena that established vocabulary often lumps together. This sheds light on the equivocations and false dichotomies of "gender" talk, and how they deny many of us the tools to make our needs, experiences, and concerns intelligible to others or even to ourselves. The authors develop a conceptual toolkit that helps alleviate the harms that result from the limitations of familiar approaches. They propose a pluralistic concept of "gender feels" that distinguishes among our experiences of diverse facets of gendered life. They develop a flexible approach to gender categories that reflects the value of self-determination. And they suggest that what we need is not one universal language of gender but an awareness of individual variation and a willingness to adjust to changing contexts and circumstances. A bold and thought-provoking approach to thinking about gender, What Even Is Gender? will be of great interest to those in philosophy, gender studies, sociology, and LGBTQIA+ studies.

Published
2023
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3. Phase transition kinetics of superionic H2O ice phases revealed by Megahertz X-ray free-electron laser-heating experiments

Author

Husband, R. J., Liermann, H. P., McHardy, J. D., McWilliams, R. S., Goncharov, A. F., Prakapenka, V. B., Edmund, E., Chariton, S., Konôpková, Z., Strohm, C., Sanchez-Valle, C., Frost, M., Andriambariarijaona, L., Appel, K., Baehtz, C., Ball, O. B., Briggs, R., Buchen, J., Cerantola, V., Choi, J., Coleman, A. L., Cynn, H., Dwivedi, A., Graafsma, H., Hwang, H., Koemets, E., Laurus, T., Lee, Y., Li, X., Marquardt, H., Mondal, A., Nakatsutsumi, M., Ninet, S., Pace, E., Pepin, C., Prescher, C., Stern, S., Sztuk-Dambietz, J., Zastrau, U., and McMahon, M. I.

Published
2024
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4. Single-photon detection in the mid-infrared up to 10 micron wavelength using tungsten silicide superconducting nanowire detectors

Author

Verma, V. B., Korzh, B., Walter, A. B., Lita, A. E., Briggs, R. M., Colangelo, M., Zhai, Y., Wollman, E. E., Beyer, A. D., Allmaras, J. P., Bumble, B., Vora, H., Zhu, D., Schmidt, E., Berggren, K. K., Mirin, R. P., Nam, S. W., and Shaw, M. D.

Subjects
Physics - Instrumentation and Detectors
Abstract

We developed superconducting nanowire single-photon detectors (SNSPDs) based on tungsten silicide (WSi) that show saturated internal detection efficiency up to a wavelength of 10 um. These detectors are promising for applications in the mid-infrared requiring ultra-high gain stability, low dark counts, and high efficiency such as chemical sensing, LIDAR, dark matter searches and exoplanet spectroscopy.

Published
2020
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5. Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European x-ray free electron laser: Quantitative structural analysis of liquid Sn.

Author

Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., and Butcher, T.

Subjects
FREE electron lasers, LIQUID analysis, ENERGY density, X-ray lasers, LASERS, LIQUID density
Abstract

X-ray free electron laser (XFEL) sources coupled to high-power laser systems offer an avenue to study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning of the DiPOLE 100-X laser on the high energy density (HED) instrument at the European XFEL represents the state-of-the-art in combining x-ray diffraction with laser compression, allowing for compressed materials to be probed in unprecedented detail. Here, we report quantitative structural measurements of molten Sn compressed to 85(5) GPa and ∼ 3500 K. The capabilities of the HED instrument enable liquid density measurements with an uncertainty of ∼ 1 % at conditions which are extremely challenging to reach via static compression methods. We discuss best practices for conducting liquid diffraction dynamic compression experiments and the necessary intensity corrections which allow for accurate quantitative analysis. We also provide a polyimide ablation pressure vs input laser energy for the DiPOLE 100-X drive laser which will serve future users of the HED instrument. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Novel experimental setup for megahertz X‐ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X‐ray Free‐Electron Laser (EuXFEL)

Author

Liermann, HP, Konôpková, Z, Appel, K, Prescher, C, Schropp, A, Cerantola, V, Husband, RJ, McHardy, JD, McMahon, MI, McWilliams, RS, Pépin, CM, Mainberger, J, Roeper, M, Berghäuser, A, Damker, H, Talkovski, P, Foese, M, Kujala, N, Ball, OB, Baron, MA, Briggs, R, Bykov, M, Bykova, E, Chantel, J, Coleman, AL, Cynn, H, Dattelbaum, D, Dresselhaus-Marais, LE, Eggert, JH, Ehm, L, Evans, WJ, Fiquet, G, Frost, M, Glazyrin, K, Goncharov, AF, Hwang, H, Jenei, Zs, Kim, J-Y, Langenhorst, F, Lee, Y, Makita, M, Marquardt, H, McBride, EE, Merkel, S, Morard, G, O'Bannon, EF, Otzen, C, Pace, EJ, Pelka, A, Pigott, JS, Prakapenka, VB, Redmer, R, Sanchez-Valle, C, Schoelmerich, M, Speziale, S, Spiekermann, G, Sturtevant, BT, Toleikis, S, Velisavljevic, N, Wilke, M, Yoo, C-S, Baehtz, C, Zastrau, U, and Strohm, C

Subjects
diamond anvil cells, X-ray free-electron lasers, high-precision X-ray diffraction, finite element modeling, Condensed Matter Physics, Optical Physics, Physical Chemistry (incl. Structural), Biophysics
Abstract

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Published
2021

14. Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European x-ray free electron laser: Quantitative structural analysis of liquid Sn

Author

Gorman, M, Mcgonegle, D, Smith, R, Singh, S, Jenkins, T, Mcwilliams, R, Albertazzi, B, Ali, S, Antonelli, L, Armstrong, M, Baehtz, C, Ball, O, Banerjee, S, Belonoshko, A, Benuzzi-Mounaix, A, Bolme, C, Bouffetier, V, Briggs, R, Buakor, K, Butcher, T, Di Dio Cafiso, S, Cerantola, V, Chantel, J, Di Cicco, A, Clarke, S, Coleman, A, Collier, J, Collins, G, Comley, A, Coppari, F, Cowan, T, Cristoforetti, G, Cynn, H, Descamps, A, Dorchies, F, Duff, M, Dwivedi, A, Edwards, C, Eggert, J, Errandonea, D, Fiquet, G, Galtier, E, Laso Garcia, A, Ginestet, H, Gizzi, L, Gleason, A, Goede, S, Gonzalez, J, Harmand, M, Hartley, N, Heighway, P, Hernandez-Gomez, C, Higginbotham, A, Höppner, H, Husband, R, Hutchinson, T, Hwang, H, Lazicki, A, Keen, D, Kim, J, Koester, P, Konopkova, Z, Kraus, D, Krygier, A, Labate, L, Lee, Y, Liermann, H, Mason, P, Masruri, M, Massani, B, Mcbride, E, Mcguire, C, Mchardy, J, Merkel, S, Morard, G, Nagler, B, Nakatsutsumi, M, Nguyen-Cong, K, Norton, A, Oleynik, I, Otzen, C, Ozaki, N, Pandolfi, S, Peake, D, Pelka, A, Pereira, K, Phillips, J, Prescher, C, Preston, T, Randolph, L, Ranjan, D, Ravasio, A, Redmer, R, Rips, J, Santamaria-Perez, D, Savage, D, Schoelmerich, M, Schwinkendorf, J, Smith, J, Sollier, A, Spear, J, Spindloe, C, Stevenson, M, Strohm, C, Suer, T, Tang, M, Toncian, M, Toncian, T, Tracy, S, Trapananti, A, Tschentscher, T, Tyldesley, M, Vennari, C, Vinci, T, Vogel, S, Volz, T, Vorberger, J, Walsh, J, Wark, J, Willman, J, Wollenweber, L, Zastrau, U, Brambrink, E, Appel, K, Mcmahon, M, Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., Butcher, T., Di Dio Cafiso, S., Cerantola, V., Chantel, J., Di Cicco, A., Clarke, S., Coleman, A. L., Collier, J., Collins, G. W., Comley, A. J., Coppari, F., Cowan, T. E., Cristoforetti, G., Cynn, H., Descamps, A., Dorchies, F., Duff, M. J., Dwivedi, A., Edwards, C., Eggert, J. H., Errandonea, D., Fiquet, G., Galtier, E., Laso Garcia, A., Ginestet, H., Gizzi, L., Gleason, A., Goede, S., Gonzalez, J. M., Harmand, M., Hartley, N. J., Heighway, P. G., Hernandez-Gomez, C., Higginbotham, A., Höppner, H., Husband, R. J., Hutchinson, T. M., Hwang, H., Lazicki, A. E., Keen, D. A., Kim, J., Koester, P., Konopkova, Z., Kraus, D., Krygier, A., Labate, L., Lee, Y., Liermann, H. -P., Mason, P., Masruri, M., Massani, B., McBride, E. E., McGuire, C., McHardy, J. D., Merkel, S., Morard, G., Nagler, B., Nakatsutsumi, M., Nguyen-Cong, K., Norton, A. -M., Oleynik, I. I., Otzen, C., Ozaki, N., Pandolfi, S., Peake, D. J., Pelka, A., Pereira, K. A., Phillips, J. P., Prescher, C., Preston, T. R., Randolph, L., Ranjan, D., Ravasio, A., Redmer, R., Rips, J., Santamaria-Perez, D., Savage, D. J., Schoelmerich, M., Schwinkendorf, J. -P., Smith, J., Sollier, A., Spear, J., Spindloe, C., Stevenson, M., Strohm, C., Suer, T. -A., Tang, M., Toncian, M., Toncian, T., Tracy, S. J., Trapananti, A., Tschentscher, T., Tyldesley, M., Vennari, C. E., Vinci, T., Vogel, S. C., Volz, T. J., Vorberger, J., Walsh, J. P. S., Wark, J. S., Willman, J. T., Wollenweber, L., Zastrau, U., Brambrink, E., Appel, K., McMahon, M. I., Gorman, M, Mcgonegle, D, Smith, R, Singh, S, Jenkins, T, Mcwilliams, R, Albertazzi, B, Ali, S, Antonelli, L, Armstrong, M, Baehtz, C, Ball, O, Banerjee, S, Belonoshko, A, Benuzzi-Mounaix, A, Bolme, C, Bouffetier, V, Briggs, R, Buakor, K, Butcher, T, Di Dio Cafiso, S, Cerantola, V, Chantel, J, Di Cicco, A, Clarke, S, Coleman, A, Collier, J, Collins, G, Comley, A, Coppari, F, Cowan, T, Cristoforetti, G, Cynn, H, Descamps, A, Dorchies, F, Duff, M, Dwivedi, A, Edwards, C, Eggert, J, Errandonea, D, Fiquet, G, Galtier, E, Laso Garcia, A, Ginestet, H, Gizzi, L, Gleason, A, Goede, S, Gonzalez, J, Harmand, M, Hartley, N, Heighway, P, Hernandez-Gomez, C, Higginbotham, A, Höppner, H, Husband, R, Hutchinson, T, Hwang, H, Lazicki, A, Keen, D, Kim, J, Koester, P, Konopkova, Z, Kraus, D, Krygier, A, Labate, L, Lee, Y, Liermann, H, Mason, P, Masruri, M, Massani, B, Mcbride, E, Mcguire, C, Mchardy, J, Merkel, S, Morard, G, Nagler, B, Nakatsutsumi, M, Nguyen-Cong, K, Norton, A, Oleynik, I, Otzen, C, Ozaki, N, Pandolfi, S, Peake, D, Pelka, A, Pereira, K, Phillips, J, Prescher, C, Preston, T, Randolph, L, Ranjan, D, Ravasio, A, Redmer, R, Rips, J, Santamaria-Perez, D, Savage, D, Schoelmerich, M, Schwinkendorf, J, Smith, J, Sollier, A, Spear, J, Spindloe, C, Stevenson, M, Strohm, C, Suer, T, Tang, M, Toncian, M, Toncian, T, Tracy, S, Trapananti, A, Tschentscher, T, Tyldesley, M, Vennari, C, Vinci, T, Vogel, S, Volz, T, Vorberger, J, Walsh, J, Wark, J, Willman, J, Wollenweber, L, Zastrau, U, Brambrink, E, Appel, K, Mcmahon, M, Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., Butcher, T., Di Dio Cafiso, S., Cerantola, V., Chantel, J., Di Cicco, A., Clarke, S., Coleman, A. L., Collier, J., Collins, G. W., Comley, A. J., Coppari, F., Cowan, T. E., Cristoforetti, G., Cynn, H., Descamps, A., Dorchies, F., Duff, M. J., Dwivedi, A., Edwards, C., Eggert, J. H., Errandonea, D., Fiquet, G., Galtier, E., Laso Garcia, A., Ginestet, H., Gizzi, L., Gleason, A., Goede, S., Gonzalez, J. M., Harmand, M., Hartley, N. J., Heighway, P. G., Hernandez-Gomez, C., Higginbotham, A., Höppner, H., Husband, R. J., Hutchinson, T. M., Hwang, H., Lazicki, A. E., Keen, D. A., Kim, J., Koester, P., Konopkova, Z., Kraus, D., Krygier, A., Labate, L., Lee, Y., Liermann, H. -P., Mason, P., Masruri, M., Massani, B., McBride, E. E., McGuire, C., McHardy, J. D., Merkel, S., Morard, G., Nagler, B., Nakatsutsumi, M., Nguyen-Cong, K., Norton, A. -M., Oleynik, I. I., Otzen, C., Ozaki, N., Pandolfi, S., Peake, D. J., Pelka, A., Pereira, K. A., Phillips, J. P., Prescher, C., Preston, T. R., Randolph, L., Ranjan, D., Ravasio, A., Redmer, R., Rips, J., Santamaria-Perez, D., Savage, D. J., Schoelmerich, M., Schwinkendorf, J. -P., Smith, J., Sollier, A., Spear, J., Spindloe, C., Stevenson, M., Strohm, C., Suer, T. -A., Tang, M., Toncian, M., Toncian, T., Tracy, S. J., Trapananti, A., Tschentscher, T., Tyldesley, M., Vennari, C. E., Vinci, T., Vogel, S. C., Volz, T. J., Vorberger, J., Walsh, J. P. S., Wark, J. S., Willman, J. T., Wollenweber, L., Zastrau, U., Brambrink, E., Appel, K., and McMahon, M. I.

Abstract

X-ray free electron laser (XFEL) sources coupled to high-power laser systems offer an avenue to study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning of the DiPOLE 100-X laser on the high energy density (HED) instrument at the European XFEL represents the state-of-the-art in combining x-ray diffraction with laser compression, allowing for compressed materials to be probed in unprecedented detail. Here, we report quantitative structural measurements of molten Sn compressed to 85(5) GPa and ∼ 3500 K. The capabilities of the HED instrument enable liquid density measurements with an uncertainty of ∼ 1 % at conditions which are extremely challenging to reach via static compression methods. We discuss best practices for conducting liquid diffraction dynamic compression experiments and the necessary intensity corrections which allow for accurate quantitative analysis. We also provide a polyimide ablation pressure vs input laser energy for the DiPOLE 100-X drive laser which will serve future users of the HED instrument.

Published
2024

15. Phase transition kinetics of superionic H2O ice phases revealed by Megahertz X-ray free-electron laser-heating experiments.

Author

Husband, R. J., Liermann, H. P., McHardy, J. D., McWilliams, R. S., Goncharov, A. F., Prakapenka, V. B., Edmund, E., Chariton, S., Konôpková, Z., Strohm, C., Sanchez-Valle, C., Frost, M., Andriambariarijaona, L., Appel, K., Baehtz, C., Ball, O. B., Briggs, R., Buchen, J., Cerantola, V., and Choi, J.

Subjects
PHASE transitions, FACE centered cubic structure, ICE sheets, LASER pulses, HIGH temperatures, FREE electron lasers, FEMTOSECOND pulses
Abstract

H2O transforms to two forms of superionic (SI) ice at high pressures and temperatures, which contain highly mobile protons within a solid oxygen sublattice. Yet the stability field of both phases remains debated. Here, we present the results of an ultrafast X-ray heating study utilizing MHz pulse trains produced by the European X-ray Free Electron Laser to create high temperature states of H2O, which were probed using X-ray diffraction during dynamic cooling. We confirm an isostructural transition during heating in the 26-69 GPa range, consistent with the formation of SI-bcc. In contrast to prior work, SI-fcc was observed exclusively above ~50 GPa, despite evidence of melting at lower pressures. The absence of SI-fcc in lower pressure runs is attributed to short heating timescales and the pressure-temperature path induced by the pump-probe heating scheme in which H2O was heated above its melting temperature before the observation of quenched crystalline states, based on the earlier theoretical prediction that SI-bcc nucleates more readily from the fluid than SI-fcc. Our results may have implications for the stability of SI phases in ice-rich planets, for example during dynamic freezing, where the preferential crystallization of SI-bcc may result in distinct physical properties across mantle ice layers. The authors perform heating experiments using femtosecond X-ray free electron laser pulses to explore the phase stability of superionic H2O. The absence of a face-centered cubic phase below 50 GPa, where superionic ice forms from the melt, is attributed to the short heating time and may help understanding the stability of superionic phases in ice-rich planets. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Replacing alfalfa hay with a novel alfalfa leaf pellet product (ProLEAF MAX) and/or alfalfa stems (ProFiber Plus) in the diet of developing dairy heifers alters dry matter intake, but does not negatively impact growth or development

Author

Motsinger, L A, primary, Young, A Y, additional, Feuz, R, additional, Larsen, R, additional, Brady, T J, additional, Briggs, R K, additional, Reichhardt, C C, additional, Pratt, C, additional, and Thornton, K J, additional

Published
2024
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17. Dynamic optical spectroscopy and pyrometry of static targets under optical and x-ray laser heating at the European XFEL.

Author

Ball, O. B., Prescher, C., Appel, K., Baehtz, C., Baron, M. A., Briggs, R., Cerantola, V., Chantel, J., Chariton, S., Coleman, A. L., Cynn, H., Damker, H., Dattelbaum, D., Dresselhaus-Marais, L. E., Eggert, J. H., Ehm, L., Evans, W. J., Fiquet, G., Frost, M., and Glazyrin, K.

Subjects
DIAMOND anvil cell, OPTICAL spectroscopy, X-ray lasers, OPTICAL measurements, FREE electron lasers, PYROMETRY, BACKGROUND radiation
Abstract

Experiments accessing extreme conditions at x-ray free electron lasers (XFELs) involve rapidly evolving conditions of temperature. Here, we report time-resolved, direct measurements of temperature using spectral streaked optical pyrometry of x-ray and optical laser-heated states at the High Energy Density instrument of the European XFEL. This collection of typical experiments, coupled with numerical models, outlines the reliability, precision, and meaning of time dependent temperature measurements using optical emission at XFEL sources. Dynamic temperatures above 1500 K are measured continuously from spectrally- and temporally-resolved thermal emission at 450–850 nm, with time resolution down to 10–100 ns for 1–200 μ s streak camera windows, using single shot and integrated modes. Targets include zero-pressure foils free-standing in air and in vacuo, and high-pressure samples compressed in diamond anvil cell multi-layer targets. Radiation sources used are 20-fs hard x-ray laser pulses at 17.8 keV, in single pulses or 2.26 MHz pulse trains of up to 30 pulses, and 250-ns infrared laser single pulses. A range of further possibilities for optical measurements of visible light in x-ray laser experiments using streak optical spectroscopy are also explored, including for the study of x-ray induced optical fluorescence, which often appears as background in thermal radiation measurements. We establish several scenarios where combined emissions from multiple sources are observed and discuss their interpretation. Challenges posed by using x-ray lasers as non-invasive probes of the sample state are addressed. [ABSTRACT FROM AUTHOR]

Published
2023
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18. SIMEX: Simulation of Experiments at Advanced Light Sources

Author

Fortmann-Grote, C, Andreev, A A, Briggs, R, Bussmann, M, Buzmakov, A, Garten, M, Grund, A, Hübl, A, Hauff, S, Joy, A, Jurek, Z, Loh, N D, Rüter, T, Samoylova, L, Santra, R, Schneidmiller, E A, Sharma, A, Wing, M, Yakubov, S, Yoon, C H, Yurkov, M V, Ziaja, B, and Mancuso, A P

Subjects
Physics - Computational Physics, Physics - Instrumentation and Detectors
Abstract

Realistic simulations of experiments at large scale photon facilities, such as optical laser laboratories, synchrotrons, and free electron lasers, are of vital importance for the successful preparation, execution, and analysis of these experiments investigating ever more complex physical systems, e.g. biomolecules, complex materials, and ultra-short lived states of highly excited matter. Traditional photon science modelling takes into account only isolated aspects of an experiment, such as the beam propagation, the photon-matter interaction, or the scattering process, making idealized assumptions about the remaining parts, e.g.\ the source spectrum, temporal structure and coherence properties of the photon beam, or the detector response. In SIMEX, we have implemented a platform for complete start-to-end simulations, following the radiation from the source, through the beam transport optics to the sample or target under investigation, its interaction with and scattering from the sample, and its registration in a photon detector, including a realistic model of the detector response to the radiation. Data analysis tools can be hooked up to the modelling pipeline easily. This allows researchers and facility operators to simulate their experiments and instruments in real life scenarios, identify promising and unattainable regions of the parameter space and ultimately make better use of valuable beamtime. This work is licensed under the Creative Commons Attribution 3.0 Unported License: http://creativecommons.org/licenses/by/3.0/., Comment: Presented at the 11th NOBUGS conference, Copenhagen, on Oct. 17th 2016. 7 pages, 3 figures, 29 references

Published
2016

19. Ramp compression of tantalum to 2.3 terapascals

Author

Gorman, M, primary, Wu, C, additional, Smith, R, additional, Benedict, L, additional, Prisbrey, C, additional, Schill, W, additional, Bonev, S, additional, Long, R, additional, Soderlind, P, additional, Braun, D, additional, Swift, D, additional, Briggs, R, additional, Volz, T, additional, O'Bannon, E, additional, Le Galloudec, K, additional, Ahrendes, L, additional, Jew, J, additional, Monzon, E, additional, Arend, M, additional, Celliers, P, additional, Fratanduono, D, additional, Eggert, J, additional, Ali, S, additional, McNaney, J, additional, Wong, H, additional, Dunn, Z, additional, Le, N, additional, Mercado, G, additional, and Lament, M, additional

Published
2022
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21. Unavoidable decoherence in the quantum control of an unknown state

Author

Kielpinski, D., Briggs, R. A., and Wiseman, H. M.

Subjects
Quantum Physics
Abstract

A common objective for quantum control is to force a quantum system, initially in an unknown state, into a particular target subspace. We show that if the subspace is required to be a decoherence-free subspace of dimension greater than 1, then such control must be decoherent. That is, it will take almost any pure state to a mixed state. We make no assumptions about the control mechanism, but our result implies that for this purpose coherent control offers no advantage, in principle, over the obvious measurement-based feedback protocol., Comment: 3 pages. To be published in Quantum Measurements & Quantum Metrology http://versita.com/qm/

Published
2013
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36. Developing New Future Scenarios for the U.S. Coast Guard's Evergreen Strategic Foresight Program

Author

Tingstad, Abbie, primary, Wilson, Michael, primary, Anania, Katherine, primary, Fischbach, Jordan, primary, Resetar, Susan, primary, Savitz, Scott, primary, Van Abel, Kristin, primary, Briggs, R., primary, Davenport, Aaron, primary, Pezard, Stephanie, primary, Sereyko, Kristin, primary, Theel, Jonathan, primary, Thibault, Marc, primary, and Ulin, Edward, primary

Published
2020
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37. Evolutionary approach for finding the atomic structure of steps on stable crystal surfaces

Author

Briggs, R. M. and Ciobanu, C. V.

Subjects
Condensed Matter - Materials Science
Abstract

The problem addressed here can be concisely formulated as follows: given a stable surface orientation with a known reconstruction and given a direction in the plane of this surface, find the atomic structure of the steps oriented along that direction. We report a robust and generally applicable variable-number genetic algorithm for step structure determination and exemplify it by determining the structure of monatomic steps on Si(114)-$2\times 1$. We show how the location of the step edge with respect to the terrace reconstructions, the step width (number of atoms), and the positions of the atoms in the step region can all be simultaneously determined., Comment: some low resolution figures due to arxiv limits

Published
2007
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38. In situ study of polymorphism and melting of metals and compounds under extreme conditions of high pressure and high temperature

Author

Briggs, R. J. and McMillan, P. F.

Subjects
540
Abstract

This thesis presents the experimental investigation of structure and melting of three important materials under extreme conditions of high pressure and high temperature. The melting points of elements and compounds are of fundamental importance for the study of planetary interiors and for fundamental and applied physics. The high pressure apparatus used in this thesis is the diamond anvil cell, which has been used to reach pressures of up to 137 GPa and temperatures up to 6000-7000 K via laser-heating techniques. The melting point has been determined at high pressure by the first onset of liquid scattering in X-ray diffraction patterns that are collected in situ. At temperatures towards the melting point, important information on the crystalline state of these materials has been extracted. The polymorphism of Sn has been studied into the megabar range (P > 100 GPa) at room temperature. The equation of state of Sn has been determined up to 137 GPa. A previously unreported structural transformation occurs at 32 GPa into a body centered orthorhombic structure (spacegroup Immm). Coexistence of this polymorph with a body centered cubic structure (spacegroup: Im-3m) is observed over a wide pressure range. These new findings for this important element are reported within. The melting relations of Sn have been determined to beyond 1 megabar in pressure and reveal a dip in the melt slope followed by a sudden sharp rise between 40 and 70 GPa. High temperature experiments using resistive-heating and laser-heating in the diamond anvil cell reveal the observation of multiple X-ray diffraction signatures at high temperatures. The results are discussed and overlap with the discoveries from the room temperature investigation of Sn. TaC and MgO are two important refractory materials and have also been investigated using laser-heated diamond anvil cell techniques combined with in situ synchrotron X-ray diffraction. TaC has the highest ambient melting temperature of any binary compound. MgO constitutes approximately 37 % of the Earth’s lower mantle and the melting temperature as a function of pressure can provide us with information on the melting behaviour, phase relations and rheology of the Earth’s lower mantle. The results and their impact on current high pressure research are discussed.

Published
2013

39. The DARHT Phase 2 Linac

Author

Rutkowski, HL, Reginato, LL, Waldron, WL, Chow, KP, Vella, MC, Fawley, WM, Briggs, R, Nelson, S, Wolf, Z, and Birx, D

Subjects
Physics - Accelerator Physics
Abstract

The second phase accelerator for the Dual Axis Hydrodynamic Test facility (DARHT) is designed to provide an electron beam pulse that is 2 microsec long, 2kA, and 20 MeV in particle energy. The injector provides 3.2 MeV so that the linac need only provide 16.8 MeV. The linac is made with two types of induction accelerator cells. The first block of 8 cells have a 14 in. beam pipe compared to 10 in. in the remaining 80 cells. The other principal difference is that the first 8 cells have reduced volt-sec in their induction cores as a result of a larger diameter beam pipe. The cells are designed for very reliable high voltage operation. The insulator is Mycalex. Results from prototype tests are given including results from solenoid measurements. Each cell contains a solenoid for beam transport and a set of x-y correction coils to reduce corkscrew motion. Details of tests to determine RF mode impedances relevant to BBU generation are given. Blocks of cells are separated by "intercells" some of which contain transport solenoids. The intercells provide vacuum pumping stations as well. Issues of alignment and installation are discussed., Comment: 3 pgs, 3 figs

Published
2000

48. Applying systems thinking to unravel the mechanisms underlying orthostatic hypotension related fall risk.

Author

Wang, L., Pronk, A.C., Poelgeest, E.P. van, Briggs, R., Claassen, J.A.H.R., Jansen, Sofie, Klop, M., Lange, F.J. De, Meskers, C.C.G.M., Odekerken, V.J.J., Payne, S.J., Trappenburg, M.C., Thijs, R.D., Uleman, J.F., Hoekstra, A.G., Velde, N. van der, Wang, L., Pronk, A.C., Poelgeest, E.P. van, Briggs, R., Claassen, J.A.H.R., Jansen, Sofie, Klop, M., Lange, F.J. De, Meskers, C.C.G.M., Odekerken, V.J.J., Payne, S.J., Trappenburg, M.C., Thijs, R.D., Uleman, J.F., Hoekstra, A.G., and Velde, N. van der

Abstract

Contains fulltext : 299851.pdf (Publisher’s version ) (Open Access), Orthostatic hypotension (OH) is an established and common cardiovascular risk factor for falls. An in-depth understanding of the various interacting pathophysiological pathways contributing to OH-related falls is essential to guide improvements in diagnostic and treatment opportunities. We applied systems thinking to multidisciplinary map out causal mechanisms and risk factors. For this, we used group model building (GMB) to develop a causal loop diagram (CLD). The GMB was based on the input of experts from multiple domains related to OH and falls and all proposed mechanisms were supported by scientific literature. Our CLD is a conceptual representation of factors involved in OH-related falls, and their interrelatedness. Network analysis and feedback loops were applied to analyze and interpret the CLD, and quantitatively summarize the function and relative importance of the variables. Our CLD contains 50 variables distributed over three intrinsic domains (cerebral, cardiovascular, and musculoskeletal), and an extrinsic domain (e.g., medications). Between the variables, 181 connections and 65 feedback loops were identified. Decreased cerebral blood flow, low blood pressure, impaired baroreflex activity, and physical inactivity were identified as key factors involved in OH-related falls, based on their high centralities. Our CLD reflects the multifactorial pathophysiology of OH-related falls. It enables us to identify key elements, suggesting their potential for new diagnostic and treatment approaches in fall prevention. The interactive online CLD renders it suitable for both research and educational purposes and this CLD is the first step in the development of a computational model for simulating the effects of risk factors on falls., 01 augustus 2023

Published
2023

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