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Your search keyword '"Sterba, Johannes H."' showing total 176 results
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176 results on '"Sterba, Johannes H."'

1. Optical Transmission Enhancement of Ionic Crystals via Superionic Fluoride Transfer: Growing VUV-Transparent Radioactive Crystals

Author

Beeks, Kjeld, Sikorsky, Tomas, Schaden, Fabian, Pressler, Martin, Schneider, Felix, Koch, Björn N., Pronebner, Thomas, Werban, David, Hosseini, Niyusha, Kazakov, Georgy, Welch, Jan, Sterba, Johannes H., Kraus, Florian, and Schumm, Thorsten

Subjects
Condensed Matter - Materials Science, Nuclear Experiment
Abstract

The 8 eV first nuclear excited state in $^{229}$Th is a candidate for implementing an nuclear clock. Doping $^{229}$Th into ionic crystals such as CaF$_2$ is expected to suppress non-radiative decay, enabling nuclear spectroscopy and the realization of a solid-state optical clock. Yet, the inherent radioactivity of $^{229}$Th prohibits the growth of high-quality single crystals with high $^{229}$Th concentration; radiolysis causes fluoride loss, increasing absorption at 8 eV. We overcome this roadblock by annealing $^{229}$Th doped CaF$_2$ at 1250$\unicode{x2103}$ in CF$_4$. The technique presented here allows to adjust the fluoride content without crystal melting, preserving its single-crystal structure. Superionic state annealing ensures rapid fluoride distribution, creating fully transparent and radiation-hard crystals. This approach enables control over the charge state of dopants which can be used in deep UV optics, laser crystals, scintillators, and nuclear clocks., Comment: 5 pages, 5 figures

Published
2023
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4. Growth and characterization of thorium-doped calcium fluoride single crystals

Author

Beeks, Kjeld, Sikorsky, Tomas, Rosecker, Veronika, Pressler, Martin, Schaden, Fabian, Werban, David, Hosseini, Niyusha, Rudischer, Lukas, Schneider, Felix, Berwian, Patrick, Friedrich, Jochen, Hainz, Dieter, Welch, Jan, Sterba, Johannes H., Kazakov, Georgy, and Schumm, Thorsten

Subjects
Condensed Matter - Materials Science, Nuclear Experiment, Physics - Atomic Physics
Abstract

We have grown $^{232}$Th:CaF$_2$ and $^{229}$Th:CaF$_2$ single crystals for investigations on the VUV laser-accessible first nuclear excited state of $^{229}$Th. To reach high doping concentrations despite the extreme scarcity (and radioactivity) of $^{229}$Th, we have scaled down the crystal volume by a factor 100 compared to established commercial or scientific growth processes. We use the vertical gradient freeze method on 3.2 mm diameter seed single crystals with a 2 mm drilled pocket, filled with a co-precipitated CaF$_2$:ThF$_4$:PbF$_2$ powder in order to grow single crystals. Concentrations of $4\cdot10^{19}$ cm$^{-3}$ have been realized with $^{232}$Th with good ($>$10%) VUV transmission. However, the intrinsic radioactivity of $^{229}$Th drives radio-induced dissociation during growth and radiation damage after solidification. Both lead to a degradation of VUV transmission, limiting the $^{229}$Th concentration to $<5\cdot10^{17}$ cm$^{-3}$., Comment: 12 pages, 18 figures

Published
2022

6. Measurement of the $^{229}$Th isomer energy with a magnetic micro-calorimeter

Author

Sikorsky, Tomas, Geist, Jeschua, Hengstler, Daniel, Kempf, Sebastian, Gastaldo, Loredana, Enss, Christian, Mokry, Christoph, Runke, Jörg, Düllmann, Christoph E., Wobrauschek, Peter, Beeks, Kjeld, Rosecker, Veronika, Sterba, Johannes H., Kazakov, Georgy, Schumm, Thorsten, and Fleischmann, Andreas

Subjects
Nuclear Experiment, Nuclear Theory, Physics - Instrumentation and Detectors
Abstract

We present a measurement of the low-energy (0--60$\,$keV) $\gamma$ ray spectrum produced in the $\alpha$-decay of $^{233}$U using a dedicated cryogenic magnetic micro-calorimeter. The energy resolution of $\sim$$10\,$eV, together with exceptional gain linearity, allow us to measure the energy of the low-lying isomeric state in $^{229}$Th using four complementary evaluation schemes. The most accurate scheme determines the $^{229}$Th isomer energy to be $8.10(17)\,$eV, corresponding to 153.1(37)$\,$nm, superseding in precision previous values based on $\gamma$ spectroscopy, and agreeing with a recent measurement based on internal conversion electrons. We also measure branching ratios of the relevant excited states to be $b_{29}=9.3(6)\%$ and $b_{42}=0.3(3)\%$., Comment: 5 pages, 5 figures + supplementary

Published
2020
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14. Optical transmission enhancement of ionic crystals via superionic fluoride transfer: Growing VUV-transparent radioactive crystals

Author

Beeks, Kjeld, primary, Sikorsky, Tomas, additional, Schaden, Fabian, additional, Pressler, Martin, additional, Schneider, Felix, additional, Koch, Björn N., additional, Pronebner, Thomas, additional, Werban, David, additional, Hosseini, Niyusha, additional, Kazakov, Georgy, additional, Welch, Jan, additional, Sterba, Johannes H., additional, Kraus, Florian, additional, and Schumm, Thorsten, additional

Published
2024
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18. Synthesis and preclinical evaluation of BOLD-100 radiolabeled with ruthenium-97 and ruthenium-103

Author

Happl, Barbara, primary, Balber, Theresa, additional, Heffeter, Petra, additional, Denk, Christoph, additional, Welch, Jan M, additional, Koester, Ulli, additional, Alliot, Cyrille, additional, Bonraisin, Anne-Cecile, additional, Brandt, Marie, additional, Haddad, Ferid, additional, Sterba, Johannes H., additional, Kandioller, Wolfgang, additional, Mitterhauser, Markus, additional, Hacker, Marcus, additional, Keppler, Bernhard K, additional, and Mindt, Thomas L., additional

Published
2024
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21. Development of a Novel Passive Monitoring Technique to Showcase the 3D Distribution of Tritiated Water (HTO) Vapor in Indoor Air of a Nuclear Facility

Author

Feng, Bin, primary, Ibesich, Martin, additional, Hainz, Dieter, additional, Waidhofer, Daniel, additional, Veit-Öller, Monika, additional, Trunner, Clemens, additional, Stummer, Thomas, additional, Foster, Michaela, additional, Nemetz, Markus, additional, Welch, Jan M., additional, Villa, Mario, additional, Sterba, Johannes H., additional, Musilek, Andreas, additional, Renz, Franz, additional, and Steinhauser, Georg, additional

Published
2023
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27. Development of a Novel Passive Monitoring Technique to Showcase the 3D Distribution of Tritiated Water (HTO) Vapor in Indoor Air of a Nuclear Facility

Author

Feng, Bin, Ibesich, Martin, Hainz, Dieter, Waidhofer, Daniel, Veit-Öller, Monika, Trunner, Clemens, Stummer, Thomas, Foster, Michaela, Nemetz, Markus, Welch, Jan M., Villa, Mario, Sterba, Johannes H., Musilek, Andreas, Renz, Franz, Steinhauser, Georg, Feng, Bin, Ibesich, Martin, Hainz, Dieter, Waidhofer, Daniel, Veit-Öller, Monika, Trunner, Clemens, Stummer, Thomas, Foster, Michaela, Nemetz, Markus, Welch, Jan M., Villa, Mario, Sterba, Johannes H., Musilek, Andreas, Renz, Franz, and Steinhauser, Georg

Abstract

Tritiated water (HTO), a ubiquitous byproduct of the nuclear industry, is a radioactive contaminant of major concern for environmental authorities. Although understanding spatiotemporal heterogeneity of airborne HTO vapor holds great importance for radiological safety as well as diagnosing a reactor’s status, comprehensive HTO distribution dynamics inside nuclear facilities has not been studied routinely yet due to a lack of appropriate monitoring techniques. For current systems, it is difficult to simultaneously achieve high representativeness, sensitivity, and spatial resolution. Here, we developed a passive monitoring scheme, including a newly designed passive sampler and a tailored analytical protocol for the first comprehensive 3D distribution characterization of HTO inside a nuclear reactor facility. The technique enables linear sampling in any environment at a one-day resolution and simultaneous preparation of hundreds of samples within 1 day. Validation experiments confirmed the method’s good metrological properties and sensitivity to the HTO’s spatial dynamics. The air in TU Wien’s reactor hall exhibits a range of 3H concentrations from 75-946 mBq m-3 in the entire 3D matrix. The HTO release rate estimated by the mass-balance model (3199 ± 306 Bq h-1) matches the theoretical calculation (2947 ± 254 Bq h-1), suggesting evaporation as the dominant HTO source in the hall. The proposed method provides reliable and quality-controlled 3D monitoring at low cost, which can be adopted not only for HTO and may also inspire monitoring schemes of other indoor pollutants.

Published
2023

28. Regional and interregional networks of ancient Eleon during the early 12th century BCE as seen from the petrographic and neutron activation analyses of pottery.

Author

Lis, Bartłomiej, Mommsen, Hans, Sterba, Johannes H., and Van Damme, Trevor

Subjects
POTTERY, CONSUMER preferences
Abstract

In this article, we present the results of application of petrographic and neutron activation analyses to a group of pottery fragments dating to the 12th century BCE deriving from ancient Eleon (Boeotia, Greece) as a means of investigating regional and interregional networks in which the site participated. Production centres in Boeotia and central Euboea provided, as could be expected, the majority of sampled pottery across various shapes. A number of more distant areas, however, such as eastern Attica, the Cyclades, Macedonia, and western Crete, are also documented in the present study, suggesting their products were available to local consumers at ancient Eleon. These results are discussed with reference to consumer preferences and exchange networks operating at that time. Finally, some of the identified petrographic and chemical groups can be securely identified at the macroscopic level, allowing us to arrive at conclusions pertinent to a substantial part of the entire pottery assemblage. [ABSTRACT FROM AUTHOR]

Published
2023
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30. The successful 'recipe' for a long-lasting tradition: Nubian ceramic assemblages from Sai Island (northern Sudan) from prehistory to the New Kingdom

Author

D'Ercole, Giulia, Budka, Julia, Sterba, Johannes H., Garcea, Elena A.A., and Mader, Dieter

Subjects
Anthropological research, Prehistoric archaeology -- Analysis, Petrography -- Analysis, Ceramic industry -- Social aspects, Anthropology/archeology/folklore
Abstract

Sai Island, in the Nile in northern Sudan, has a series of settlement sites spanning the entire period from the eighth millennium BC through to the Eighteenth Dynasty of the Egyptian New Kingdom. This long sequence provides an excellent opportunity to study continuity and discontinuity in long-term pottery traditions. Ceramics from the varying cultural phases of the occupation reflect changing dynamics between broader regional social identities, notably Kerma to the south and Egypt to the north. Combining studies of petrography with trace element composition and chaine operatoire analysis, the authors present the first diachronic study of ceramic manufacture throughout the extended cultural history of Nubia, highlighting the varying manifestations of change and continuity. Keywords: Sudan, Nubia, ceramics, manufacture, continuity, chaine operatoire, petrography, instrumental neutron activation analysis (INAA), Introduction The concept of continuity implies the maintenance of given traits in artefactual assemblages and their reiteration through time. These traits commonly form a tradition or cultural inheritance. According to [...]

Published
2017
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39. Production centers of cooking pots in Iron Age Judah.

Author

Ben‐Shlomo, David, Bouzaglou, Liora, Mommsen, Hans, and Sterba, Johannes H.

Subjects
IRON Age, NUCLEAR activation analysis, COOKING
Abstract

This paper will present and discuss a multifaceted research project dealing with the production of cooking pots during the Iron Age II (ca. 1,000–586 BCE) Judah (modern Israel). In particular the new compositional analysis of 541 cooking vessels from 11 sites in Iron Age Judah will be presented. The study employs petrographic and chemical (NAA) analysis. The results of this ongoing research have already produced interesting information about production centers and movements of cooking pots in Iron Age II Judah. Apparently, the vast majority of the cooking pots sampled were made of a similar type of clay, related to terra rossa soil. This is true also for sites in the northern Negev and Judean Desert, where the type of soil was not available in the region of the sites. Furthermore, many of the cooking pots distributed around Judah were made in Jerusalem according to a well‐located chemical profile (JleB). Other groups may represent Judean Shephelah production centers as the Lachish area as well as production centers in southern Israel or ancient Edom. The implications of the importation patterns of cooking pots by peripheral Judean sites will be discussed. [ABSTRACT FROM AUTHOR]

Published
2023
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40. Radiochemical effects of thermal neutron capture in Cr(tmhd)3: method development.

Author

Pichler, Vanessa, Welch, Jan M., and Sterba, Johannes H.

Subjects
NEUTRON capture, THERMAL neutrons, RADIOCHEMICAL purification, COLUMN chromatography, THIN layer chromatography, NEUTRON irradiation, RECRYSTALLIZATION (Metallurgy)
Abstract

The radiochemical effects of thermal neutron capture in tris(2,2,6,6-tetramethyl-3,5-heptandionato)chromium(III) (Cr(tmhd)3) were investigated. A method was devised to quantify the amount of the induced 51Cr activity recoverable in the original chemical form and to confirm that it is indeed Cr(tmhd)3. The method is based on a combination of chemical separation (column chromatography and recrystallization) and analytical (radio-TLC, HPLC, and gamma spectrometry) techniques. Cr(tmhd)3 samples were irradiated and purified in two steps after irradiation. We found that two of the (three) purification pathways yielded good agreement among final 51Cr activity concentrations. The corresponding samples appeared to be of exceptional radiochemical purity. [ABSTRACT FROM AUTHOR]

Published
2022
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47. Looking for Ephesian workshops: An integrated petrographic, geochemical and chrono- typological approach on Late Hellenistic Ephesos lamps

Author

Fragnoli, Pamela, Ugarković, Marina, Sterba, Johannes H., Sauer, Roman

Subjects
Ephesos . Late Hellenistic mold-made lamps . workshops . craft organization . petrography . NAA
Abstract

In this pilot study, Late Hellenistic mold-made lamps from Ephesos are investigated by combining chrono-morphological and stylistic features with thin-section petrography and neutron activation analysis. Coeval wares of Ephesian production and clay samples collected around the site as well as published data from the Bonn database are considered local reference material. The results point to a network of local/regional workshops sharing facilities and/or a labor force dedicated to distinct tasks. The whole evidence is consistent with the very beginning of a nucleated workshop industry able to optimize the productivity of mold-made wares and fill the demand of an increased regional and supra-regional market. The typological and compositional variability of the latest phases could suggest a gradual transfer of potting activities towards areas providing better-suited clay sources.

Published
2021

48. Peer review versus editorial review and their role in innovative science

Author

Steinhauser, Georg, Adlassnig, Wolfram, Risch, Jesaka Ahau, Anderlini, Serena, Arguriou, Petros, Armendariz, Aaron Zolen, Bains, William, Baker, Clark, Barnes, Martin, Barnett, Jonathan, Baumgartner, Michael, Baumgartner, Thomas, Bendall, Charles A., Bender, Yvonne S., Bichler, Max, Biermann, Teresa, Bini, Ronaldo, Blanco, Eduardo, Bleau, John, Brink, Anthony, Brown, Darin, Burghuber, Christopher, Calne, Roy, Carter, Brian, Castaño, Cesar, Celec, Peter, Celis, Maria Eugenia, Clarke, Nicky, Cockrell, David, Collins, David, Coogan, Brian, Craig, Jennifer, Crilly, Cal, Crowe, David, Csoka, Antonei B., Darwich, Chaza, del Kebos, Topiciprin, DeRinaldi, Michele, Dlamini, Bongani, Drewa, Tomasz, Dwyer, Michael, Eder, Fabienne, de Palma, Raúl Ehrichs, Esmay, Dean, Rött, Catherine Evans, Exley, Christopher, Falkov, Robin, Farber, Celia Ingrid, Fearn, William, Felsmann, Sophie, Flensmark, Jarl, Fletcher, Andrew K., Foster, Michaela, Fountoulakis, Kostas N., Fouratt, Jim, Blanca, Jesus Garcia, Sotelo, Manuel Garrido, Gittler, Florian, Gittler, Georg, Gomez, Juan, Gomez, Juan F., Polar, Maria Grazia Gonzales, Gonzalez, Jossina, Gösselsberger, Christoph, Habermacher, Lynn, Hajek, Michael, Hakala, Faith, Haliburton, Mary-Sue, Hankins, John Robert, Hart, Jason, Hasslberger, Sepp, Hennessey, Donalyn, Herrmann, Andrea, Hersee, Mike, Howard, Connie, Humphries, Suzanne, Isharc, Laeeth, Ivanovski, Petar, Jenuth, Stephen, Jerndal, Jens, Johnson, Christine, Keleta, Yonas, Kenny, Anna, Kidd, Billie, Kohle, Fritz, Kolahi, Jafar, Koller-Peroutka, Marianne, Kostova, Lyubov, Kumar, Arunachalam, Kurosawa, Alejandro, Lance, Tony, Lechermann, Michael, Lendl, Bernhard, Leuchters, Michael, Lewis, Evan, Lieb, Edward, Lloyd, Gloria, Losek, Angelika, Lu, Yao, Maestracci, Saadia, Mangan, Dennis, Mares, Alberto W., Barnett, Juan Mazar, McClain, Valerie, McNair, John Sydney, Michael, Terry, Miller, Lloyd, Monzani, Partizia, Moran, Belen, Morris, Mike, Mößmer, Georg, Mountain, Johny, Phuthe, Onnie Mary Moyo, Muñoz, Marcos, Nakken, Sheri, Wambui, Anne Nduta, Neunteufl, Bettina, Nikolić, Dimitrije, Oberoi, Devesh V., Obmode, Gregory, Ogar, Laura, Ohara, Jo, Rybine, Naion Olej, Owen, Bryan, Owen, Kim Wilson, Parikh, Rakesh, Pearce, Nicholas J. G., Pemmer, Bernhard, Piper, Chris, Prince, Ian, Reid, Terence, Rindermann, Heiner, Risch, Stefan, Robbins, Josh, Roberts, Seth, Romero, Ajeandro, Rothe, Michael Thaddäus, Ruiz, Sergio, Sacher, Juliane, Sackl, Wolfgang, Salletmaier, Markus, Sanand, Jairaj, Sauerzopf, Clemens, Schwarzgruber, Thomas, Scott, David, Seegers, Laura, Seppi, David, Shields, Kyle, Siller-Matula, Jolanta, Singh, Beldeu, Sithole, Sibusio, Six, Florian, Skoyles, John R., Slofstra, Jildou, Sole, Daphne Anne, Sommer, Werner F., Sonko, Mels, Starr-Casanova, Chrislie J., Steakley, Marjorie Elizabeth, Steinhauser, Wolfgang, Steinhoff, Konstantin, Sterba, Johannes H., Steppan, Martin, Stindl, Reinhard, Stokely, Joe, Stokely, Karri, St-Pierre, Gilles, Stratford, James, Streli, Christina, Stryg, Carl, Sullivan, Mike, Summhammer, Johann, Tadesse, Amhayes, Tavares, David, Thompson, Laura, Tomlinson, Alison, Tozer, Jack, Trevisanato, Siro I., Trimmel, Michaela, Turner, Nicole, Vahur, Paul, van der Byl, Jennie, van der Maas, Tine, Varela, Leo, Vega, Carlos A., Vermaak, Shiloh, Villasenor, Alex, Vogel, Matt, von Wintzigerode, Georg, Wagner, Christoph, Weinberger, Manuel, Weinberger, Peter, Wilson, Nick, Wolfe, Jennifer Finocchio, Woodley, Michael A., Young, Ian, Zuraw, Glenn, and Zwiren, Nicole

Published
2012
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