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2,265 results on '"Preston, T."'

1. Plasma screening in mid-charged ions observed by K-shell line emission

Author

Šmıd, M., Humphries, O., Baehtz, C., Brambrink, E., Burian, T., Cho, M. S., Cowan, T. E., Gaus, L., Gu, M. F., Hájková, V., Juha, L., Konopkova, Z., Le, H. P., Makita, M., Pan, X., Preston, T., Schropp, A., Scott, H. A., Štefanıková, R., Vorberger, J., Wang, W., Zastrau, U., and Falk, K.

Subjects
Physics - Plasma Physics
Abstract

Dense plasma environment affects the electronic structure of ions via variations of the microscopic electrical fields, also known as plasma screening. This effect can be either estimated by simplified analytical models, or by computationally expensive and to date unverified numerical calculations. We have experimentally quantified plasma screening from the energy shifts of the bound-bound transitions in matter driven by the x-ray free electron laser (XFEL). This was enabled by identification of detailed electronic configurations of the observed K{\alpha}, K\b{eta} and K{\gamma} lines. This work paves the way for improving plasma screening models including connected effects like ionization potential depression and continuum lowering, which will advance the understanding of atomic physics in Warm Dense Matter regime.

Published
2024

2. Dielectronic satellite emission from a solid-density Mg plasma: relationship to models of ionisation potential depression

Author

Pérez-Callejo, G., Gawne, T., Preston, T. R., Hollebon, P., Humphries, O. S., Chung, H. -K., Dakovski, G. L., Krzywinski, J., Minitti, M. P., Burian, T., Chalupský, J., Hájková, V., Juha, L., Vozda, V., Zastrau, U., Vinko, S. M., Rose, S. J., and Wark, J. S.

Subjects
High Energy Physics - Experiment, Physics - Plasma Physics
Abstract

We report on experiments where solid-density Mg plasmas are created by heating with the focused output of the Linac Coherent Light Source x-ray free-electron-laser. We study the K-shell emission from the Helium and Lithium-like ions using Bragg crystal spectroscopy. Observation of the dielectronic satellites in Lithium-like ions confirms that the M-shell electrons appear bound for these high charge states. An analysis of the intensity of these satellites indicates that when modelled with an atomic-kinetics code, the ionisation potential depression model employed needs to produce depressions for these ions which lie between those predicted by the well known Stewart-Pyatt and Ecker-Kroll models. These results are largely consistent with recent Density Functional Theory calculations.

Published
2023
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4. Heart transplantation and human immunodeficiency virus–navigating drug-drug interactions: a case report

Author

Thamer A. Almangour, Preston T. Skersick, Amanda Corbett, Jo E. Rodgers, Patricia P. Chang, and Claire E. Farel

Subjects
Heart transplantation, Human immunodeficiency virus, Case report, Immunologic diseases. Allergy, RC581-607
Abstract

Abstract Background Antiretroviral therapy (ART) has led to a decline in human immunodeficiency virus (HIV)-related mortality, but comorbidities, including organ dysfunction, are increasingly the focus of care. Heart transplant (HT) is a very effective therapeutic strategy for end-stage heart failure (HF); however, clinicians may be hesitant due to concerns of complex drug-drug interactions (DDIs) between ART and HT immunosuppressive regimens and the potential impact of ART on long-term HT outcomes. In this report, we describe long-term (76-month) follow-up of a patient with HIV-positive status who underwent orthotopic HT with special emphasis on complex drug interactions. Case presentation A 58-year-old man with HIV-1 developed ischemic cardiomyopathy, progressed to end-stage HF and underwent orthotopic HT. To avoid DDIs with planned immunosuppressive therapies, the ART regimen was modified to consist of lamivudine, tenofovir disoproxil fumarate, rilpivirine, and raltegravir. Following HT, the patient’s immunosuppression consisted of tacrolimus and mycophenolate mofetil. He has had normal cardiac function and no opportunistic infections and was subsequently switched to tenofovir alafenamide, emtricitabine, and bictegravir in combination for convenience. Serial HIV-1 RNA blood levels were constantly below the limit of quantification, and his CD4 count remained above 200 cells/mm3 (30–35%). Several DDIs were identified and addressed; however, his long-term post-HT complications included one episode of asymptomatic acute cellular rejection, adenocarcinoma of the prostate, basal cell carcinoma, cardiac allograft vasculopathy, and peripheral neuropathy. Conclusion The clinical outcome of this case supports the conclusion of previously published reports, summarized here within, demonstrating that HIV-1 positive status should not preclude HT in carefully selected individuals. Both addressing potential DDIs prior to HT and long-term monitoring for routine post-transplant complications and secondary and incidental malignancies are imperative.

Published
2023
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5. Time-resolved XUV Opacity Measurements of Warm-Dense Aluminium

Author

Vinko, S. M., Vozda, V., Andreasson, J., Bajt, S., Bielecki, J., Burian, T., Chalupsky, J., Ciricosta, O., Desjarlais, M. P., Fleckenstein, H., Hajdu, J., Hajkova, V., Hollebon, P., Juha, L., Kasim, M. F., McBride, E. E., Muehlig, K., Preston, T. R., Rackstraw, D. S., Roling, S., Toleikis, S., Wark, J. S., and Zacharias, H.

Subjects
Physics - Plasma Physics, Physics - Computational Physics, Physics - Data Analysis, Statistics and Probability
Abstract

The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order the Fermi energy. Plasma heating and opacity-enhancement is observed on ultrafast time scales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm-dense matter.

Published
2020
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8. Swimming Performance Assessments of Fish Species of Greatest Conservation Need to Inform Future Stream Crossing Designs in Texas

Author

Cameron M. Emadi, Preston T. Bean, and Edward M. Mager

Subjects
swimming performance, metabolism, stream crossing, Ucrit, Biology (General), QH301-705.5, Genetics, QH426-470
Abstract

Conventional structures associated with stream crossings such as bridges and culverts can lead to zones of high-velocity water flow that impede fish passage. Such obstacles are likely to harm native fish populations by impacting migrations critical to their life history strategies, causing habitat fragmentation and extirpation, thereby limiting population growth and distribution. Due to the high rates of human population growth and development occurring in Texas, this is an issue of particular concern for fish designated as species of greatest conservation need (SGCN). This project focused on four SGCN fishes native to the Edwards Plateau Ecoregion, namely the Guadalupe Bass, Guadalupe Roundnose Minnow, Guadalupe Darter, and Plateau Shiner, at both adult (all species) and juvenile (Guadalupe Bass only) life stages. Our primary aim was to aid in the design of future culverts associated with stream crossings (or the modification of existing culverts) so that the water velocities through these structures do not exceed the swimming capacities of our target SGCN fishes. To this end, we assessed their maximum sustained swimming speeds (Ucrit) under a typical range of Edwards Plateau stream temperatures (15, 22.5, and 30 °C) to be used in site-specific calculations of the maximum allowable culvert water velocities (Vf). A secondary objective was to collect physiological endpoints of relevance to the overall swimming performance including the maximum burst swimming speeds (Umax), metabolic rate measurements (i.e., standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS)), cost of transport (COT), and optimal swimming speed (Uopt). Temperature-related effects were observed that can be used to inform site-specific culvert designs. In general, the highest Ucrit values for the tested species were near, or possibly between, 22.5 and 30 °C, while Umax stayed relatively consistent among treatments.

Published
2024
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9. 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

12. Nucleation control of quantum dot synthesis in a microfluidic continuous flow reactor

Author

Eun Byoel Kim, Kyle M. Tomczak, Hashini B. Chandrasiri, Marcell Pálmai, Amirreza Ghaznavi, Dmitry Gritsenko, Jie Xu, and Preston T. Snee

Subjects
microfluidic, cadmium selenide, quantum dot (QD), nucleation, artificial intelligence (AI), Chemical technology, TP1-1185
Abstract

The use of microfluidics in chemical synthesis is topical due to the potential to improve reproducibility and the ability promptly interrogate a wide range of reaction parameters, the latter of which is necessary for the training of artificial intelligence (AI) algorithms. Applying microfluidic techniques to semiconductor nanocrystals, or quantum dots (QDs), is challenging due to the need for a high-temperature nucleation event followed by particle growth at lower temperatures. Such a high-temperature gradient can be realized using complex, segmented microfluidic reactor designs, which represents an engineering approach. Here, an alternative chemical approach is demonstrated using the cluster seed method of nanoparticle synthesis in a simple microfluidic reactor system. This enables quantum dot nucleation at lower temperatures due to the presence of molecular organometallic compounds (NMe4)4[Cd10Se4(SPh)16] and (NMe4)4[Zn10Se4(SPh)16]. This integration of cluster seeding with microfluidics affords a new mechanism to tailor the reaction conditions for optimizing yields and tuning product properties.

Published
2023
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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. G., primary, McGonegle, D., additional, Smith, R. F., additional, Singh, S., additional, Jenkins, T., additional, McWilliams, R. S., additional, Albertazzi, B., additional, Ali, S. J., additional, Antonelli, L., additional, Armstrong, M. R., additional, Baehtz, C., additional, Ball, O. B., additional, Banerjee, S., additional, Belonoshko, A. B., additional, Benuzzi-Mounaix, A., additional, Bolme, C. A., additional, Bouffetier, V., additional, Briggs, R., additional, Buakor, K., additional, Butcher, T., additional, Di Dio Cafiso, S., additional, Cerantola, V., additional, Chantel, J., additional, Di Cicco, A., additional, Clarke, S., additional, Coleman, A. L., additional, Collier, J., additional, Collins, G. W., additional, Comley, A. J., additional, Coppari, F., additional, Cowan, T. E., additional, Cristoforetti, G., additional, Cynn, H., additional, Descamps, A., additional, Dorchies, F., additional, Duff, M. J., additional, Dwivedi, A., additional, Edwards, C., additional, Eggert, J. H., additional, Errandonea, D., additional, Fiquet, G., additional, Galtier, E., additional, Laso Garcia, A., additional, Ginestet, H., additional, Gizzi, L., additional, Gleason, A., additional, Goede, S., additional, Gonzalez, J. M., additional, Harmand, M., additional, Hartley, N. J., additional, Heighway, P. G., additional, Hernandez-Gomez, C., additional, Higginbotham, A., additional, Höppner, H., additional, Husband, R. J., additional, Hutchinson, T. M., additional, Hwang, H., additional, Lazicki, A. E., additional, Keen, D. A., additional, Kim, J., additional, Koester, P., additional, Konopkova, Z., additional, Kraus, D., additional, Krygier, A., additional, Labate, L., additional, Lee, Y., additional, Liermann, H.-P., additional, Mason, P., additional, Masruri, M., additional, Massani, B., additional, McBride, E. E., additional, McGuire, C., additional, McHardy, J. D., additional, Merkel, S., additional, Morard, G., additional, Nagler, B., additional, Nakatsutsumi, M., additional, Nguyen-Cong, K., additional, Norton, A.-M., additional, Oleynik, I. I., additional, Otzen, C., additional, Ozaki, N., additional, Pandolfi, S., additional, Peake, D. J., additional, Pelka, A., additional, Pereira, K. A., additional, Phillips, J. P., additional, Prescher, C., additional, Preston, T. R., additional, Randolph, L., additional, Ranjan, D., additional, Ravasio, A., additional, Redmer, R., additional, Rips, J., additional, Santamaria-Perez, D., additional, Savage, D. J., additional, Schoelmerich, M., additional, Schwinkendorf, J.-P., additional, Smith, J., additional, Sollier, A., additional, Spear, J., additional, Spindloe, C., additional, Stevenson, M., additional, Strohm, C., additional, Suer, T.-A., additional, Tang, M., additional, Toncian, M., additional, Toncian, T., additional, Tracy, S. J., additional, Trapananti, A., additional, Tschentscher, T., additional, Tyldesley, M., additional, Vennari, C. E., additional, Vinci, T., additional, Vogel, S. C., additional, Volz, T. J., additional, Vorberger, J., additional, Walsh, J. P. S., additional, Wark, J. S., additional, Willman, J. T., additional, Wollenweber, L., additional, Zastrau, U., additional, Brambrink, E., additional, Appel, K., additional, and McMahon, M. I., additional

Published
2024
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15. Dielectronic satellite emission from a solid-density Mg plasma: Relationship to models of ionization potential depression

Author

Pérez-Callejo, G., primary, Gawne, T., additional, Preston, T. R., additional, Hollebon, P., additional, Humphries, O. S., additional, Chung, H.-K., additional, Dakovski, G. L., additional, Krzywinski, J., additional, Minitti, M. P., additional, Burian, T., additional, Chalupský, J., additional, Hájková, V., additional, Juha, L., additional, Vozda, V., additional, Zastrau, U., additional, Vinko, S. M., additional, Rose, S. J., additional, and Wark, J. S., additional

Published
2024
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16. Impact of unintentional Sb in the tensile InAs layer of strain-balanced type-II InAs/InAsSb superlattices grown on GaSb by molecular beam epitaxy.

Author

Milosavljevic, Marko S., Webster, Preston T., and Johnson, Shane R.

Subjects
*MOLECULAR beam epitaxy, *SUPERLATTICES, *MOLE fraction, *PHOTOLUMINESCENCE measurement, *QUANTUM dots
Abstract

The impact of unintentional incorporation of Sb in the tensile InAs layer of type-II strain-balanced InAs/InAsSb superlattices is investigated. Several coherently strained midwave and longwave superlattices are grown on (100) GaSb substrates by molecular beam epitaxy and examined using x-ray diffraction and temperature-dependent photoluminescence spectroscopy. The zero-order diffraction angle provides the average Sb mole fraction of the strain-balanced superlattice period. Analysis of the higher order diffraction angles, along with the individual layer growth times and strain, provides the InAs and InAsSb layer thicknesses. Analysis of the photoluminescence measurements provides the ground-state bandgap of the superlattice, which along with simulations of the ground-state energies of the electrons and holes using a Kronig–Penney model, specify how the Sb is distributed between the tensile and compressive layers of the period and ultimately the quantity of unintentional Sb in the InAs layer. The unintentional Sb mole fractions observed in the tensile InAs layers are 1.9% for midwave and 1.2% for longwave. When compared to superlattices with the same period and no Sb in the tensile layer, the presence of unintentional Sb blue-shifts the 77 K temperature cutoff wavelength from 6.3 to 5.3 μm for midwave and from 18.8 to 12.0 μm for longwave. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Operational experience with Adaptive Gain Integrating Pixel Detectors at European XFEL

Author

Sztuk-Dambietz, J., Rovensky, V., Klujev, A., Laurus, T., Trunk, U., Ahmed, K., Meyer, O., Möller, J., Parenti, A., Raab, N., Shayduk, R., Sikorski, M., Ansaldi, G., Bösenberg, U., Luis, L. M., Muenich, A., Preston, T. R., Schmidt, P., Stern, S., Bean, R., Madsen, A., Gelisio, L., Hauf, S., Gessler, P., Wrona, K., Graafsma, Heinz, Turcato, M., Sztuk-Dambietz, J., Rovensky, V., Klujev, A., Laurus, T., Trunk, U., Ahmed, K., Meyer, O., Möller, J., Parenti, A., Raab, N., Shayduk, R., Sikorski, M., Ansaldi, G., Bösenberg, U., Luis, L. M., Muenich, A., Preston, T. R., Schmidt, P., Stern, S., Bean, R., Madsen, A., Gelisio, L., Hauf, S., Gessler, P., Wrona, K., Graafsma, Heinz, and Turcato, M.

Abstract

The European X-ray Free Electron Laser (European XFEL) is a cutting-edge user facility that generates per second up to 27,000 ultra-short, spatially coherent X-ray pulses within an energy range of 0.26 to more than 20 keV. Specialized instrumentation, including various 2D X-ray detectors capable of handling the unique time structure of the beam, is required. The one-megapixel AGIPD (AGIPD1M) detectors, developed for the European XFEL by the AGIPD Consortium, are the primary detectors used for user experiments at the SPB/SFX and MID instruments. The first AGIPD1M detector was installed at SPB/SFX when the facility began operation in 2017, and the second one was installed at MID in November 2018. The AGIPD detector systems require a dedicated infrastructure, well-defined safety systems, and high-level control procedures to ensure stable and safe operation. As of now, the AGIPD1M detectors installed at the SPB/SFX and MID experimental end stations are fully integrated into the European XFEL environment, including mechanical integration, vacuum, power, control, data acquisition, and data processing systems. Specific high-level procedures allow facilitated detector control, and dedicated interlock systems based on Programmable Logic Controllers ensure detector safety in case of power, vacuum, or cooling failure. The first 6 years of operation have clearly demonstrated that the AGIPD1M detectors provide high-quality scientific results. The collected data, along with additional dedicated studies, have also enabled the identification and quantification of issues related to detector performance, ensuring stable operation. Characterization and calibration of detectors are among the most critical and challenging aspects of operation due to their complex nature. A methodology has been developed to enable detector characterization and data correction, both in near real-time (online) and offline mode. The calibration process optimizes detector performance and ensures the highest

Published
2024
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20. Visualizing plasmons and ultrafast kinetic instabilities in laser-driven solids using X-ray scattering

Author

(0009-0007-5067-7326) Ordyna, P., Bähtz, C., (0009-0004-2404-9412) Brambrink, E., (0000-0002-8258-3881) Bussmann, M., (0000-0002-7671-0901) Laso García, A., (0000-0001-6994-2475) Garten, M., (0000-0002-6914-4083) Gaus, L., Göde, S., Grenzer, J., (0000-0002-0051-8542) Gutt, C., Höppner, H., (0000-0003-1184-2097) Huang, L., Hübner, U., (0000-0001-6748-0422) Humphries, O. S., (0009-0005-6873-8292) Edward Marré, B., (0000-0002-9556-0662) Metzkes-Ng, J., (0000-0002-9933-3248) Miethlinger, T., (0000-0003-0868-4745) Nakatsutsumi, M., Öztürk, Ö., (0000-0002-3882-510X) Pan, X., (0009-0001-0047-1051) Paschke-Brühl, F.-L., (0009-0001-3308-5376) Pelka, A., (0000-0003-0931-1350) Prencipe, I., (0000-0003-1228-2263) Preston, T. R., (0000-0001-9587-404X) Randolph, L., (0000-0003-4400-1315) Schlenvoigt, H.-P., Schwinkendorf, J.-P., (0000-0002-7162-7500) Šmíd, M., (0000-0001-5007-1868) Starke, S., (0000-0002-4195-2038) Štefaníková, R., Thiessenhusen, E., (0000-0001-7986-3631) Toncian, T., (0000-0003-3926-409X) Zeil, K., (0000-0003-0390-7671) Schramm, U., (0000-0002-5845-000X) Cowan, T., (0000-0003-4861-5584) Kluge, T., (0009-0007-5067-7326) Ordyna, P., Bähtz, C., (0009-0004-2404-9412) Brambrink, E., (0000-0002-8258-3881) Bussmann, M., (0000-0002-7671-0901) Laso García, A., (0000-0001-6994-2475) Garten, M., (0000-0002-6914-4083) Gaus, L., Göde, S., Grenzer, J., (0000-0002-0051-8542) Gutt, C., Höppner, H., (0000-0003-1184-2097) Huang, L., Hübner, U., (0000-0001-6748-0422) Humphries, O. S., (0009-0005-6873-8292) Edward Marré, B., (0000-0002-9556-0662) Metzkes-Ng, J., (0000-0002-9933-3248) Miethlinger, T., (0000-0003-0868-4745) Nakatsutsumi, M., Öztürk, Ö., (0000-0002-3882-510X) Pan, X., (0009-0001-0047-1051) Paschke-Brühl, F.-L., (0009-0001-3308-5376) Pelka, A., (0000-0003-0931-1350) Prencipe, I., (0000-0003-1228-2263) Preston, T. R., (0000-0001-9587-404X) Randolph, L., (0000-0003-4400-1315) Schlenvoigt, H.-P., Schwinkendorf, J.-P., (0000-0002-7162-7500) Šmíd, M., (0000-0001-5007-1868) Starke, S., (0000-0002-4195-2038) Štefaníková, R., Thiessenhusen, E., (0000-0001-7986-3631) Toncian, T., (0000-0003-3926-409X) Zeil, K., (0000-0003-0390-7671) Schramm, U., (0000-0002-5845-000X) Cowan, T., and (0000-0003-4861-5584) Kluge, T.

Abstract

Ultra-intense lasers that ionize atoms and accelerate electrons in solids to near the speed of light can lead to kinetic instabilities that alter the laser absorption and subsequent electron transport, isochoric heating, and ion acceleration. These instabilities can be difficult to characterize, but X-ray scattering at keV photon energies allows for their visualization with femtosecond temporal resolution on the few nanometer mesoscale. Here, we perform such experiment on laser-driven flat silicon membranes that shows the development of structure with a dominant scale of 60 nm in the plane of the laser axis and laser polarization, and 95 nm in the vertical direction with a growth rate faster than 0.1 fs−1 . Combining the XFEL experiments with simulations provides a complete picture of the structural evolution of ultra-fast laser-induced plasma density development, indicating the excita- tion of plasmons and a filamentation instability. Particle-in-cell simulations confirm that these signals are due to an oblique two-stream filamentation instability. These findings provide new insight into ultra-fast instability and heating processes in solids under extreme conditions at the nanometer level with possible implications for laser particle acceleration, inertial confinement fusion, and laboratory astrophysics.

Published
2024

21. Ultrahigh Resolution X-ray Thomson Scattering Measurements of Electronic Structures

Author

(0000-0001-9998-3606) Gawne, T. D., (0000-0002-9725-9208) Moldabekov, Z., Humphries, O. S., Appel, K., Bähtz, C., Bouffetier, V., Brambrink, E., (0000-0001-9162-262X) Cangi, A., Göde, S., Konôpková, Z., Makita, M., Mishchenko, M., Nakatsutsumi, M., (0000-0003-4211-2484) Ramakrishna, K., Randolph, L., (0000-0002-4561-0158) Schwalbe, S., (0000-0001-5926-9192) Vorberger, J., Wollenweber, L., Zastrau, U., (0000-0001-7293-6615) Dornheim, T., Preston, T. R., (0000-0001-9998-3606) Gawne, T. D., (0000-0002-9725-9208) Moldabekov, Z., Humphries, O. S., Appel, K., Bähtz, C., Bouffetier, V., Brambrink, E., (0000-0001-9162-262X) Cangi, A., Göde, S., Konôpková, Z., Makita, M., Mishchenko, M., Nakatsutsumi, M., (0000-0003-4211-2484) Ramakrishna, K., Randolph, L., (0000-0002-4561-0158) Schwalbe, S., (0000-0001-5926-9192) Vorberger, J., Wollenweber, L., Zastrau, U., (0000-0001-7293-6615) Dornheim, T., and Preston, T. R.

Abstract

Using a novel ultrahigh resolution (\Delta E ~ 0.1eV) setup to measure electronic features in x-ray Thomson scattering (XRTS) experiments at the European XFEL in Germany, we have studied the collective plasmon excitation in aluminium at ambient conditions, which we can measure very accurately even at low momentum transfers. As a result, we can resolve previously reported discrepancies between ab initio time-dependent density functional theory simulations and experimental observations. The demonstrated capability for high-resolution XRTS measurements will be a game changer for the diagnosis of experiments with matter under extreme densities, temperatures, and pressures, and unlock the full potential of state-of-the-art x-ray free electron laser (XFEL) facilities to study planetary interior conditions, to understand inertial confinement fusion applications, and for material science and discovery.

Published
2024

22. X-ray Thomson scattering absolute intensity from the f-sum rule in the imaginary-time domain

Author

(0000-0001-7293-6615) Dornheim, T., Döppner, T., Baczewski, A. D., Tolias, P., (0000-0003-0290-3628) Böhme, M., (0000-0002-9725-9208) Moldabekov, Z., (0000-0002-8641-4794) Ranjan, D., Chapman, D. A., Macdonald, M. J., Preston, T. R., (0000-0002-6350-4180) Kraus, D., (0000-0001-5926-9192) Vorberger, J., (0000-0001-7293-6615) Dornheim, T., Döppner, T., Baczewski, A. D., Tolias, P., (0000-0003-0290-3628) Böhme, M., (0000-0002-9725-9208) Moldabekov, Z., (0000-0002-8641-4794) Ranjan, D., Chapman, D. A., Macdonald, M. J., Preston, T. R., (0000-0002-6350-4180) Kraus, D., and (0000-0001-5926-9192) Vorberger, J.

Abstract

We evaluate the f-sum rule on the dynamic structure factor in the imaginary-time domain as a formally exact and simulation-free means of normalizing X-Ray Thomson Scattering (XRTS) spectra. This circumvents error-prone real-time deconvolution of the source function and facilitates calculating the static structure factor from the properly normalized imaginary-time correlation function. We apply our technique to two distinct sets of experimental data, finding that it is effective for both narrow and broad x-ray sources. This approach could be readily adapted to other scattering spectroscopies.

Published
2024

23. Revealing Non-equilibrium and Relaxation in Laser Heated Matter

Author

(0000-0001-5926-9192) Vorberger, J., Preston, T. R., Medvedev, N., (0000-0003-0290-3628) Böhme, M., (0000-0002-9725-9208) Moldabekov, Z., (0000-0002-6350-4180) Kraus, D., (0000-0001-7293-6615) Dornheim, T., (0000-0001-5926-9192) Vorberger, J., Preston, T. R., Medvedev, N., (0000-0003-0290-3628) Böhme, M., (0000-0002-9725-9208) Moldabekov, Z., (0000-0002-6350-4180) Kraus, D., and (0000-0001-7293-6615) Dornheim, T.

Abstract

Experiments creating extreme states of matter almost invariably create non-equilibrium states. These are very interesting in their own right but need to be understood even if the ultimate goal is to probe high pressure or high temperature equilibrium properties like the equation of state. Here, we report on the capabilities of the newly developed imaginary time correlation function (ITCF) technique [1] to detect and quantify non-equilibrium in pump-probe experiments fielding time resolved x-ray scattering diagnostics. We find a high sensitivity of the ITCF even to a small fraction of non-equilibrium electrons in the Wigner distribution. The behavior of the ITCF technique is such that modern lasers and detectors should be able to trace the non-equilibrium relaxation from tens of femto-seconds to several 10s of picoseconds without the need for a model.

Published
2024

24. Ion emission from warm dense matter produced by irradiation with a soft x-ray free-electron laser

Author

(0000-0002-3888-8370) Krása, J., (0000-0003-3982-9978) Burian, T., (0000-0002-0776-6012) Hájková, V., (0000-0001-6930-1774) Chalupský, J., (0000-0002-1999-811X) Jelínek, Š., (0000-0001-8743-9531) Frantálová, K., (0000-0003-0784-4145) Krupka, M., (0000-0002-5939-4097) Kuglerová, Z., (0000-0001-5754-2431) Kumar Singh, S., (0000-0002-5426-1519) Vozda, V., (0000-0002-8549-0859) Vyšín, L., (0000-0002-7162-7500) Smid, M., (0000-0002-2767-9995) Perez-Martin, P., (0009-0003-3427-3082) Kühlman, M., (0000-0002-4243-0282) Pintor, J., (0000-0002-8222-8038) Cikhardt, J., (0009-0008-0393-6580) Dreimann, M., Eckermann, D., Rosenthal, F., (0000-0003-1016-0975) Vinko, S. M., (0000-0002-2872-7223) Forte, A., (0000-0001-9998-3606) Gawne, T. D., (0000-0002-0104-1424) Campbell, T., Ren, S., (0000-0002-7723-2331) Shi, Y., (0000-0003-1882-3702) Hutchinson, T., (0000-0001-6748-0422) Humphries, O. S., (0000-0003-1228-2263) Preston, T., (0000-0003-1513-9198) Makita, M., (0000-0003-0868-4745) Nakatsutsumi, M., (0000-0002-3882-510X) Pan, X., (0000-0001-9759-1166) Köhler, A., (0000-0003-0713-5824) Harmand, M., (0009-0008-2136-7780) Toleikis, S., (0000-0001-5975-776X) Falk, K., (0000-0003-4189-8753) Juha, L., (0000-0002-3888-8370) Krása, J., (0000-0003-3982-9978) Burian, T., (0000-0002-0776-6012) Hájková, V., (0000-0001-6930-1774) Chalupský, J., (0000-0002-1999-811X) Jelínek, Š., (0000-0001-8743-9531) Frantálová, K., (0000-0003-0784-4145) Krupka, M., (0000-0002-5939-4097) Kuglerová, Z., (0000-0001-5754-2431) Kumar Singh, S., (0000-0002-5426-1519) Vozda, V., (0000-0002-8549-0859) Vyšín, L., (0000-0002-7162-7500) Smid, M., (0000-0002-2767-9995) Perez-Martin, P., (0009-0003-3427-3082) Kühlman, M., (0000-0002-4243-0282) Pintor, J., (0000-0002-8222-8038) Cikhardt, J., (0009-0008-0393-6580) Dreimann, M., Eckermann, D., Rosenthal, F., (0000-0003-1016-0975) Vinko, S. M., (0000-0002-2872-7223) Forte, A., (0000-0001-9998-3606) Gawne, T. D., (0000-0002-0104-1424) Campbell, T., Ren, S., (0000-0002-7723-2331) Shi, Y., (0000-0003-1882-3702) Hutchinson, T., (0000-0001-6748-0422) Humphries, O. S., (0000-0003-1228-2263) Preston, T., (0000-0003-1513-9198) Makita, M., (0000-0003-0868-4745) Nakatsutsumi, M., (0000-0002-3882-510X) Pan, X., (0000-0001-9759-1166) Köhler, A., (0000-0003-0713-5824) Harmand, M., (0009-0008-2136-7780) Toleikis, S., (0000-0001-5975-776X) Falk, K., and (0000-0003-4189-8753) Juha, L.

Abstract

We report on an experiment performed at the FLASH2 free-electron laser (FEL) aimed at producing warm dense matter via soft x-ray isochoric heating. In the experiment, we focus on study of the ions emitted during the soft x-ray ablation process using time-of-flight electron multipliers and a shifted Maxwell–Boltzmann velocity distribution model. We find that most emitted ions are thermal, but that some impurities chemisorbed on the target surface, such as protons, are accelerated by the electrostatic field created in the plasma by escaped electrons. The morphology of the complex crater structure indicates the presence of several ion groups with varying temperatures. We find that the ion sound velocity is controlled by the ion temperature and show how the ion yield depends on the FEL radiation attenuation length in different materials.

Published
2024

25. Evidence of free-bound transitions in warm dense matter

Author

(0000-0001-7293-6615) Dornheim, T., (0000-0003-0290-3628) Böhme, M., (0000-0002-6350-4180) Kraus, D., Preston, T., Döppner, T., (0000-0002-9725-9208) Moldabekov, Z., Baczewski, A., Fletcher, L., (0000-0001-5926-9192) Vorberger, J., (0000-0001-7293-6615) Dornheim, T., (0000-0003-0290-3628) Böhme, M., (0000-0002-6350-4180) Kraus, D., Preston, T., Döppner, T., (0000-0002-9725-9208) Moldabekov, Z., Baczewski, A., Fletcher, L., and (0000-0001-5926-9192) Vorberger, J.

Abstract

Warm dense matter (WDM) is now routinely created and probed in laboratories around the world, providing unprecedented insights into conditions achieved in stellar atmospheres, planetary interiors, and inertial confinement fusion experiments. However, the interpretation of these experiments is often filtered through models with systematic errors that are difficult to quantify. Due to the simultaneous presence of quantum degeneracy and thermal excitation, processes in which free electrons are de-excited into thermally unoccupied bound states transferring momentum and energy to a scattered x-ray photon become viable [1]. Here we show that such free-bound transitions are a particular feature of WDM and vanish in the limits of cold and hot temperatures. The inclusion of these processes into the analysis of recent X-ray Thomson Scattering (XRTS) experiments on WDM at the National Ignition Facility [2] (see the figure below) and the Linac Coherent Light Source [3] significantly improves model fits, indicating that free- bound transitions have been observed without previously being identified. This interpretation is corroborated by agreement with a recently developed model-free thermometry technique [4,5] and presents an important step for precisely characterizing and understanding the complex WDM state of matter.

Published
2024

29. Auger-limited minority carrier lifetime in GeSn/SiGeSn quantum well

Author

Grant, Perry C., primary, Webster, Preston T., additional, Carrasco, Rigo A., additional, Logan, Julie V., additional, Hains, Christopher P., additional, Gajowski, Nathan, additional, Yu, Shui-Qing, additional, Li, Baohua, additional, Morath, Christian P., additional, and Maestas, Diana, additional

Published
2024
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32. Capacitance–voltage modeling of mid-wavelength infrared nBn detectors.

Author

Carrasco, Rigo A., Newell, Alexander T., Alsaad, Zinah M., Logan, Julie V., Duran, Joshua M., Ariyawansa, Gamini, Pinkie, Benjamin, Morath, Christian P., and Webster, Preston T.

Subjects
INFRARED detectors, SCHOTTKY barrier diodes, SEMICONDUCTOR doping, SEMICONDUCTOR junctions, FINITE element method, ELECTRIC capacity, QUANTUM cascade lasers
Abstract

Capacitance–voltage measurements are a powerful technique to determine doping profiles of semiconductor pn junctions and Schottky barrier diodes. The measurements were recently extended to III-V-based mid-wavelength nBn infrared detectors, and absorber doping densities have been extracted using the widely accepted Schottky approximation, where the potential drop across the device is assumed to be across the depleting absorber layer. However, this approach is limited to when the absorber region of the nBn is under high reverse bias and thus is only able to extract the absorber region doping profile. Here, we introduce a semi-analytical model that is capable of extracting barrier dopant polarity, doping concentration, and thickness, as well as contact and absorber layer doping concentrations, all from a capacitance–voltage measurement. Rather than solely considering the potential drop across the depleting layers, it considers the potential drop across the accumulating layer as well. This negative charge accumulation occurs for the contact and absorber layers in the case of reverse and forward biases, respectively. This allows for a single model to be applied to a capacitance–voltage curve at forward and reverse biases and it can provide regions of bias where the absorber transitions from depletion to accumulation. We compare the agreement of the semianalytical model with modeling results from commercially available finite element method software and experimental capacitance–voltage data. Finally, we show that the method is consistent with the Schottky approximation of extracting absorber doping densities at high reverse bias and discuss the model's limitations. [ABSTRACT FROM AUTHOR]

Published
2023
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33. Toward using collective x-ray Thomson scattering to study C-H demixing and hydrogen metallization in warm dense matter conditions

Author

Ranjan, D, Ramakrishna, K, Voigt, K, Humphries, O, Heuser, B, Stevenson, M, Lütgert, J, He, Z, Qu, C, Schumacher, S, May, P, Amouretti, A, Appel, K, Brambrink, E, Cerantola, V, Chekrygina, D, Fletcher, L, Göde, S, Harmand, M, Hartley, N, Hau-Riege, S, Makita, M, Pelka, A, Schuster, A, Šmíd, M, Toncian, T, Zhang, M, Preston, T, Zastrau, U, Vorberger, J, Kraus, D, Ranjan D., Ramakrishna K., Voigt K., Humphries O. S., Heuser B., Stevenson M. G., Lütgert J., He Z., Qu C., Schumacher S., May P. T., Amouretti A., Appel K., Brambrink E., Cerantola V., Chekrygina D., Fletcher L. B., Göde S., Harmand M., Hartley N. J., Hau-Riege S. P., Makita M., Pelka A., Schuster A. K., Šmíd M., Toncian T., Zhang M., Preston T. R., Zastrau U., Vorberger J., Kraus D., Ranjan, D, Ramakrishna, K, Voigt, K, Humphries, O, Heuser, B, Stevenson, M, Lütgert, J, He, Z, Qu, C, Schumacher, S, May, P, Amouretti, A, Appel, K, Brambrink, E, Cerantola, V, Chekrygina, D, Fletcher, L, Göde, S, Harmand, M, Hartley, N, Hau-Riege, S, Makita, M, Pelka, A, Schuster, A, Šmíd, M, Toncian, T, Zhang, M, Preston, T, Zastrau, U, Vorberger, J, Kraus, D, Ranjan D., Ramakrishna K., Voigt K., Humphries O. S., Heuser B., Stevenson M. G., Lütgert J., He Z., Qu C., Schumacher S., May P. T., Amouretti A., Appel K., Brambrink E., Cerantola V., Chekrygina D., Fletcher L. B., Göde S., Harmand M., Hartley N. J., Hau-Riege S. P., Makita M., Pelka A., Schuster A. K., Šmíd M., Toncian T., Zhang M., Preston T. R., Zastrau U., Vorberger J., and Kraus D.

Abstract

The insulator-metal transition in liquid hydrogen is an important phenomenon to understand the interiors of gas giants, such as Jupiter and Saturn, as well as the physical and chemical behavior of materials at high pressures and temperatures. Here, the path toward an experimental approach is detailed based on spectrally resolved x-ray scattering, tailored to observe and characterize hydrogen metallization in dynamically compressed hydrocarbons in the regime of carbon-hydrogen phase separation. With the help of time-dependent density functional theory calculations and scattering spectra from undriven carbon samples collected at the European x-ray Free-Electron Laser Facility (EuXFEL), we demonstrate sufficient data quality for observing C-H demixing and investigating the presence of liquid metallic hydrogen in future experiments using the reprated drive laser systems at EuXFEL.

Published
2023

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

Author

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

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

35. Multi-Horizon Predictive Soil Mapping of Historical Soil Properties Using Remote Sensing Imagery

Author

Preston T. Sorenson, Jeremy Kiss, Angela K. Bedard-Haughn, and Steve Shirtliffe

Subjects
Saskatchewan, predictive soil mapping, bare soil composite imagery, multi-temporal remote sensing, random forest, Science
Abstract

There is increasing demand for more detailed soil maps to support fine-scale land use planning, soil carbon management, and precision agriculture in Saskatchewan. Predictive soil mapping that incorporates a combination of environmental covariates provides a cost-effective tool for generating finer resolution soil maps. This study focused on mapping soil properties for multiple soil horizons in Saskatchewan using historical legacy soil data in combination with remote sensing band indices, bare soil composite imagery, climate data, and terrain attributes. Mapped soil properties included soil organic carbon content (SOC), total nitrogen, cation exchange capacity (CEC), electrical conductivity (EC), inorganic carbon (IOC), sand and clay content, and total profile soil organic carbon stocks. For each of these soil properties, a recursive feature elimination was undertaken to reduce the number of features in the overall model. This process involved iteratively removing features such that random forest out-of-bag error was minimized. Final random forest models were built for each property and evaluated using an independent test dataset. Overall, predictive models were successful for SOC (R2 = 0.71), total nitrogen (R2 = 0.65), CEC (R2 = 0.46), sand content (R2 = 0.44) and clay content (R2 = 0.55). The methods used in this study enable mapping of a greater geographic region of Saskatchewan compared to those previously established that relied solely on bare soil composite imagery.

Published
2022
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36. Swimming Performance Assessments of Fish Species of Greatest Conservation Need to Inform Future Stream Crossing Designs in Texas.

Author

Emadi, Cameron M., Bean, Preston T., and Mager, Edward M.

Subjects
*WILDLIFE conservation, *LIFE history theory, *SWIMMING, *WATER temperature, *FRAGMENTED landscapes, *FISH populations, *FISHWAYS
Abstract

Conventional structures associated with stream crossings such as bridges and culverts can lead to zones of high-velocity water flow that impede fish passage. Such obstacles are likely to harm native fish populations by impacting migrations critical to their life history strategies, causing habitat fragmentation and extirpation, thereby limiting population growth and distribution. Due to the high rates of human population growth and development occurring in Texas, this is an issue of particular concern for fish designated as species of greatest conservation need (SGCN). This project focused on four SGCN fishes native to the Edwards Plateau Ecoregion, namely the Guadalupe Bass, Guadalupe Roundnose Minnow, Guadalupe Darter, and Plateau Shiner, at both adult (all species) and juvenile (Guadalupe Bass only) life stages. Our primary aim was to aid in the design of future culverts associated with stream crossings (or the modification of existing culverts) so that the water velocities through these structures do not exceed the swimming capacities of our target SGCN fishes. To this end, we assessed their maximum sustained swimming speeds (Ucrit) under a typical range of Edwards Plateau stream temperatures (15, 22.5, and 30 °C) to be used in site-specific calculations of the maximum allowable culvert water velocities (Vf). A secondary objective was to collect physiological endpoints of relevance to the overall swimming performance including the maximum burst swimming speeds (Umax), metabolic rate measurements (i.e., standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS)), cost of transport (COT), and optimal swimming speed (Uopt). Temperature-related effects were observed that can be used to inform site-specific culvert designs. In general, the highest Ucrit values for the tested species were near, or possibly between, 22.5 and 30 °C, while Umax stayed relatively consistent among treatments. [ABSTRACT FROM AUTHOR]

Published
2024
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37. Impact of Inpatient Initiation of SGLT2 Inhibitors on Diuretic Requirements in Patients With Heart Failure.

Author

Cavagnini, Megan E., Best, Emily E., Skersick, Preston T., Truitt, Kelsey P., Musick, Kaitlin L., Mangum, Blake R., Hollis, Ian B., and Rodgers, Jo E.

Subjects
KIDNEY physiology, BLOOD sugar analysis, CREATININE, HOSPITAL care, SCIENTIFIC observation, DRUG therapy, HEART failure, DIURETICS, TREATMENT effectiveness, HOSPITALS, RETROSPECTIVE studies, BLOOD urea nitrogen, DESCRIPTIVE statistics, LONGITUDINAL method, SODIUM-glucose cotransporter 2 inhibitors, SODIUM, CARDIOVASCULAR agents
Abstract

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have been shown to improve outcomes in patients with heart failure (HF) and are now included in guideline-directed medical therapy. Trials reporting the change in loop diuretic dose following SGLT2i initiation have indicated conflicting results. There is no clear guidance on whether reducing loop diuretic doses following SGLT2i initiation is appropriate. Objective: The purpose of this study is to assess the impact of SGLT2i initiation on diuretic adjustment in hospitalized patients with known or new HF. Methods: This was a retrospective, single health-system study assessing the change in loop diuretic dose in the 60 days following discharge for patients with HF initiated on SGLT2i therapy during a hospital admission or upon discharge. Secondary outcomes assessed effect on renal function and discontinuation of SGLT2i within the 60 day follow up period. Results: Forty percent of patients required loop diuretic dose adjustment, with 29% requiring a dose reduction within the 60 days following discharge. There was minimal change in serum creatinine or blood urea nitrogen. The SGLT2i was discontinued in 6 patients. Conclusions: After inpatient initiation of SGLT2is, approximately one-third of patients required a reduction in loop diuretic dose within 60 days following hospital discharge. Further study is recommended to confirm if empiric diuretic dose adjustments are appropriate in this HF population. [ABSTRACT FROM AUTHOR]

Published
2024
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40. SkyMapper and the Southern Sky Survey

Author

Keller, S. C., Schmidt, B. P., Bessell, M. S., Conroy, P. G., Francis, P., Granlund, A., Kowald, E., Oates, A. P., Martin-Jones, T., Preston, T., Tisserand, P., Vaccarella, A., and Waterson, M. F.

Subjects
Astrophysics
Abstract

This paper presents the design and science goals for the SkyMapper telescope. SkyMapper is a 1.3m telescope featuring a 5.7 square degree field-of-view Cassegrain imager commissioned for the Australian National University's Research School of Astronomy and Astrophysics. It is located at Siding Spring Observatory, Coonabarabran, NSW, Australia and will see first light in late 2007. The imager possesses 16kx16k 0.5 arcsec pixels. The primary scientific goal of the facility is to perform the Southern Sky Survey, a six colour and multi-epoch (4 hour, 1 day, 1 week, 1 month, 1 year sampling) photometric survey of the southerly 2pi steradians to g~23 mag. The survey will provide photometry to better than 3% global accuracy and astrometry to better than 50 mas. Data will be supplied to the community as part of the Virtual Observatory effort. The survey will take five years to complete.

Published
2007
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44. The Sliding-Aperture Transform and Its Applicability to Deep-Level Transient Spectroscopy

Author

Walter R. Buchwald, Robert E. Peale, Perry C. Grant, Julie V. Logan, Preston T. Webster, and Christian P. Morath

Subjects
DLTS, transient analysis, emission rate, extraction, curve fitting, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

A mathematical method is presented for the extraction of defect parameters from the multiexponential decays generated during deep-level transient spectroscopy experiments. Such transient phenomenon results from the ionization of charge trapped in defects located in the depletion width of a semiconductor diode. From digitized transients acquired at fixed temperatures, this method produces a rate–domain spectral signature associated with all defects in the semiconductor. For signal-to-noise ratio of 1000, defect levels with carrier emission rates differing by as little as 1.5 times may be distinguished.

Published
2022
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45. Gray Luvisols are polygenetic

Author

Miles F. Dyck, Preston T. Sorenson, Justine D.M. Lejoly, and Sylvie A. Quideau

Subjects
Soil Science
Abstract

With respect to the pedosphere, human activities in the last 100 years have been the major driver of soil change. Despite human activities being one of the main soil forming factors recognized by soil scientists (in addition to climate, organisms, parent material, relief, groundwater, and time), the Canadian System of Soil Classification (CSSC) emphasizes soil as a natural body. We argue human agricultural activities are direct and indirect drivers of significant changes to the carbon balance and cycling in A horizons of Gray Luvisolic soils in western Canada, resulting in changes to A horizon carbon stocks, structure, and micromorphology. Evidence from scientific literature, in-field soil profile observations, and the National Pedon Database are presented in support of our argument. We propose a polygenetic, two-stage model of Gray Luvisol soil formation. The first stage is dominated by the climate forcing of the Holocene, resulting in a relatively stable boreal forest ecosystem including perturbations from natural and human-induced wildfire and other disturbances. The second stage is dominated by direct, human-driven disturbances such as cultivation, release of exotic fauna (earthworms), and indirect human-driven disturbances associated with anthropogenic climate change. Further, we propose modest amendments to the CSSC to reflect a polygenetic model of soil genesis in Gray Luvisolic soils that preserve the balance between observation and interpretation inherent in the system.

Published
2023
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46. Changing environmental gradients over forty years alter ecomorphological variation in Guadalupe Bass Micropterus treculii throughout a river basin

Author

Jessica E. Pease, Timothy B. Grabowski, Allison A. Pease, and Preston T. Bean

Subjects
Centrarchidae, ecomorphology, flow alteration, intraspecific trait variation, urbanization, Ecology, QH540-549.5
Abstract

Abstract Understanding the degree of intraspecific variation within and among populations is a key aspect of predicting the capacity of a species to respond to anthropogenic disturbances. However, intraspecific variation is usually assessed at either limited temporal, but broad spatial scales or vice versa, which can make assessing changes in response to long‐term disturbances challenging. We evaluated the relationship between the longitudinal gradient of changing flow regimes and land use/land cover patterns since 1980 and morphological variation of Guadalupe Bass Micropterus treculii throughout the Colorado River Basin of central Texas. The Colorado River Basin in Texas has experienced major alterations to the hydrologic regime due to changing land‐ and water‐use patterns. Historical collections of Guadalupe Bass prior to rapid human‐induced change present the unique opportunity to study the response of populations to varying environmental conditions through space and time. Morphological differentiation of Guadalupe Bass associated with temporal changes in flow regimes and land use/land cover patterns suggests that they are exhibiting intraspecific trait variability, with contemporary individuals showing increased body depth, in response to environmental alteration through time (specifically related to an increase in herbaceous land cover, maximum flows, and the number of low pulses and high pulses). Additionally, individuals from tributaries with increased hydrologic alteration associated with urbanization or agricultural withdrawals tended to have a greater distance between the anal and caudal fin. These results reveal trait variation that may help to buffer populations under conditions of increased urbanization and sprawl, human population growth, and climate risk, all of which impose novel selective pressures, especially on endemic species like Guadalupe Bass. Our results contribute an understanding of the adaptability and capacity of an endemic population to respond to expected future changes based on demographic or climatic projection.

Published
2018
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48. An approach for the measurement of the bulk temperature of single crystal diamond using an X-ray free electron laser

Author

Descamps, A., Ofori-Okai, B. K., Appel, K., Cerantola, V., Comley, A., Eggert, J. H., Fletcher, L. B., Gericke, D. O., Göde, S., Humphries, O., Karnbach, O., Lazicki, A., Loetzsch, R., McGonegle, D., Palmer, C. A. J., Plueckthun, C., Preston, T. R., Redmer, R., Senesky, D. G., Strohm, C., Uschmann, I., White, T. G., Wollenweber, L., Monaco, G., Wark, J. S., Hastings, J. B., Zastrau, U., Gregori, G., Glenzer, S. H., and McBride, E. E.

Published
2020
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49. Predictive soil mapping in the Boreal Plains of Northern Alberta by using multi-temporal remote sensing data and terrain derivatives

Author

Preston T. Sorenson, Jeremy Kiss, Anna Serdetchnaia, Javed Iqbal, and Angela K. Bedard-Haughn

Subjects
Soil Science
Abstract

As Canada's vast Boreal Plains are extensively managed, predictive soil mapping could be used as an effective tool to generate high-resolution soil information for the region to inform sustainable resource management. This study aimed to investigate the use of multi-temporal remote sensing data and terrain derivatives to map soil types in the region. A method of constraining subgroup and great-group soil-type predictions based on the predictions at higher-order levels (great-group and order, respectively) was tested. Sentinel time series median values obtained by using Google Earth Engine were tested in combination with first- and second-order digital elevation model derivatives for use as predictor variables in the predictive models. A recursive feature selection process was implemented to reduce the number of predictor variables used in model training. Soil classes were predicted at the order, great-group, and subgroup levels and two approaches were tested. In the first approach, models were unconstrained based on previous predictions. In the second approach, models were constrained to predict only soil great-group classes that occur within the predicted soil order for a given location and similarly predict only soil subgroup classes that occur within the predicted soil great group for a given location. Determined through independent validation testing, the most probable predicted soil maps had overall accuracies ranging from 42% to 68% and kappa scores ranging from 0.33 to 0.48. Overall, the constrained models had the best performance of the approaches tested.

Published
2022
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