6,502 results on '"Choi, B"'
Search Results
2. The use of botulinum toxin in the acute management of symptomatic complex incisional hernia: a case series
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Stevens, J., Baillie, C., Choi, B., Chapman, A., Kostalas, M., and Ratnasingham, K.
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- 2023
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3. Wide-field Hemodynamic Neuroimaging of Rodents using a Modified openSFDI Build
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Phan, T, Crouzet, C, Kennedy, GT, Durkin, AJ, and Choi, B
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We modified and combined an open-source spatial frequency domain imaging (openSFDI) build with laser speckle imaging (LSI) into a widefield rodent cortical hemodynamic imaging system. Here, we present system specifications and in-vitro phantom measurement results.
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- 2022
4. An Interaction Neyman-Scott Point Process Model for Coronavirus Disease-19
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Park, J., Chang, W., and Choi, B.
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Statistics - Applications ,Statistics - Methodology - Abstract
With rapid transmission, the coronavirus disease 2019 (COVID-19) has led to over 2 million deaths worldwide, posing significant societal challenges. Understanding the spatial patterns of patient visits and detecting the local spreading events are crucial to controlling disease outbreaks. We analyze highly detailed COVID-19 contact tracing data collected from Seoul, which provides a unique opportunity to understand the mechanism of patient visit occurrence. Analyzing contact tracing data is challenging because patient visits show strong clustering patterns while clusters of events may have complex interaction behavior. To account for such behaviors, we develop a novel interaction Neyman-Scott process that regards the observed patient visit events as offsprings generated from a parent spreading event. Inference for such models is complicated since the likelihood involves intractable normalizing functions. To address this issue, we embed an auxiliary variable algorithm into our Markov chain Monte Carlo. We fit our model to several simulated and real data examples under different outbreak scenarios and show that our method can describe spatial patterns of patient visits well. We also provide visualization tools that can inform public health interventions for infectious diseases such as social distancing.
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- 2021
5. A Regression Model for Tool Wear and Breakage Diagnosis
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Kim, S. G., Heo, E. Y., Lee, H. G., Kim, W., Choi, B. B., So, H. W., Kim, D. W., Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Haddar, Mohamed, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Kim, Kyoung-Yun, editor, Monplaisir, Leslie, editor, and Rickli, Jeremy, editor
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- 2023
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6. Visualizing Orbital Content of Electronic Bands in Anisotropic 2D Semiconducting ReSe$_{2}$
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Choi, B. K., Ulstrup, S., Gunasekera, S. M., Kim, J., Lim, S. Y., Moreschini, L., Oh, J. S., Chun, S. -H., Jozwiak, C., Bostwick, A., Rotenberg, E., Cheong, H., Lyo, I. -W., Mucha-Kruczynski, M., and Chang, Y. J.
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Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science - Abstract
Many properties of layered materials change as they are thinned from their bulk forms down to single layers, with examples including indirect-to-direct band gap transition in 2H semiconducting transition metal dichalcogenides as well as thickness-dependent changes in the valence band structure in post-transition metal monochalcogenides and black phosphorus. Here, we use angle-resolved photoemission spectroscopy to study the electronic band structure of monolayer ReSe$_{2}$, a semiconductor with a distorted 1T structure and in-plane anisotropy. By changing the polarization of incoming photons, we demonstrate that for ReSe$_{2}$, in contrast to the 2H materials, the out-of-plane transition metal $d_{z^{2}}$ and chalcogen $p_{z}$ orbitals do not contribute significantly to the top of the valence band which explains the reported weak changes in the electronic structure of this compound as a function of layer number. We estimate a band gap of 1.7 eV in pristine ReSe$_{2}$ using scanning tunneling spectroscopy and explore the implications on the gap following surface-doping with potassium. A lower bound of 1.4 eV is estimated for the gap in the fully doped case, suggesting that doping-dependent many-body effects significantly affect the electronic properties of ReSe$_{2}$. Our results, supported by density functional theory calculations, provide insight into the mechanisms behind polarization-dependent optical properties of rhenium dichalcogenides and highlight their place amongst two-dimensional crystals., Comment: 37 pages (including Supporting Information), 7 figures in the main text
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- 2020
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7. Final closure of the saemangeum tidal dike, South Korea
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Ha, J.W., MSc, D. Eo, Kim, K. O, Deng, and Choi, B. H.
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- 2011
8. Sustainable recycling process for tantalum recovery from printed circuit boards
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Choi, B., Domínguez, B., D'Souza, A., Khadse, H., Kunkel, A., Nagarajan, S., Necke, T., Peche, R., Revello, M., Rossa, J., Sauer, F., Huyer, S., Schulz, O., Vorwerg, S., Walls, C., Wickleder, M., and Beck, G.
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- 2023
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9. The Berkeley sample of Type II supernovae: BVRI light curves and spectroscopy of 55 SNe II
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de Jaeger, T., Zheng, W., Stahl, B. E., Filippenko, A. V., Brink, T. G., Bigley, A., Blanchard, K., Blanchard, P. K., Bradley, J., Cargill, S. K., Casper, C., Cenko, S. B., Channa, S., Choi, B. Y., Clubb, K. I., Cobb, B. E., Cohen, D., de Kouchkovsky, M., Ellison, M., Falcon, E., Fox, O. D., Fuller, K., Ganeshalingam, M., Gould, C., Graham, M. L., Halevi, G., Hayakawa, K. T., Hestenes, J., Hyland, M. P., Jeffers, B., Joubert, N., Kandrashoff, M. T., Kelly, P. L., Kim, H., Kim, M., Kumar, S., Leonard, E. J., Li, G. Z., Lowe, T. B., Lu, P., Mason, M., McAllister, K. J., Mauerhan, J. C., Modjaz, M., Molloy, J., Perley, D. A., Pina, K., Poznanski, D., Ross, T. W., Shivvers, I., Silverman, J. M., Soler, C., Stegman, S., Taylor, S., Tang, K., Wilkins, A., Wang, Xiaofeng, Wang, Xianggao, Yuk, H., Yunus, S., and Zhang, K. D.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
In this work, BV RI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search program obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 days for a total of 5093 photometric points. In average V-band plateau declines with a rate of 1.29 mag (100 days)-1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudoequivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 days post-explosion and has a median ejecta expansion velocity at 50 days post-explosion of 6500 km/s (Halpha line) and a standard dispersion of 2000 km/s. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16 Msol. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators., Comment: 24 pages, 12 figures, accepted for publication in MNRAS
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- 2019
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10. RAMSES II - RAMan Search for Extragalactic Symbiotic Stars. Project concept, commissioning, and early results from the science verification phase
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Angeloni, R., Gonçalves, D. R., Akras, S., Gimeno, G., Diaz, R., Scharwächter, J., Nuñez, N. E., Luna, G. J. M., Lee, H. W., Heo, J. E., Lucy, A. B., Arancibia, M. Jaque, Moreno, C., Chirre, E., Goodsell, S. J., King, P. Soto, Sokoloski, J. L., Choi, B. E., and Ribeiro, M. Dias
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Symbiotic stars (SySts) are long-period interacting binaries composed of a hot compact star, an evolved giant star, and a tangled network of gas and dust nebulae. They represent unique laboratories for studying a variety of important astrophysical problems, and have also been proposed as possible progenitors of SNIa. Presently, we know 257 SySts in the Milky Way and 69 in external galaxies. However, these numbers are still in striking contrast with the predicted population of SySts in our Galaxy. Because of other astrophysical sources that mimic SySt colors, no photometric diagnostic tool has so far demonstrated the power to unambiguously identify a SySt, thus making the recourse to costly spectroscopic follow-up still inescapable. In this paper we present the concept, commissioning, and science verification phases, as well as the first scientific results, of RAMSES II - a Gemini Observatory Instrument Upgrade Project that has provided each GMOS instrument at both Gemini telescopes with a set of narrow-band filters centered on the Raman OVI 6830 A band. Continuum-subtracted images using these new filters clearly revealed known SySts with a range of Raman OVI line strengths, even in crowded fields. RAMSES II observations also produced the first detection of Raman OVI emission from the SySt LMC 1 and confirmed Hen 3-1768 as a new SySt - the first photometric confirmation of a SySt. Via Raman OVI narrow-band imaging, RAMSES II provides the astronomical community with the first purely photometric tool for hunting SySts in the local Universe., Comment: 23 pages, 16 figures, 5 tables, accepted for publication in AJ
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- 2019
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11. Studies of the crystal structure of solid solutions (Sn2)1−x−y(GaAs)x(ZnSe)y, (GaAs)1−x(ZnSe)x grown from liquid phase
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Razzokov, A.Sh., Saidov, A.S., Allabergenov, B., Choi, B., Petrushenko, S.I., and Dukarov, S.V.
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- 2023
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12. Precise asymptotics of weighted sequences and their applications
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Choi, B. J., Ji, U. C., and Shin, D.
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- 2022
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13. Holmium:yttrium‐aluminium‐garnet laser with MOSES technology is more efficient than thulium fibre laser in supine mini‐percutaneous nephrolithotomy.
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Vergamini, Lucas B., Ito, Willian, Choi B, Nicholas, Du, Holly E., Sardiu, Mihaela E., Neff, Donald, Duchene, David A., Molina, Wilson R., and Whiles, Bristol B.
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LASER lithotripsy ,THULIUM ,LASERS ,URINARY calculi ,URINARY diversion ,COMPUTED tomography - Abstract
Objectives: To address the paucity of literature comparing outcomes achieved with utilisation of the high‐power holmium:yttrium‐aluminium‐garnet (Ho:YAG) laser with MOSES technology vs those achieved with the thulium fibre laser (TFL) in mini‐percutaneous nephrolithotomy (PCNL). Methods: A retrospective review was performed of patients undergoing supine mini‐PCNL between August 2021 and May 2023. Exclusion criteria were urinary diversion, simultaneous utilisation of >1 laser platform, use of any other form of fragmentation, and ureteric stones. The Ho:YAG platform (Lumenis Pulse P120H™ with MOSES technology, 120W; Boston Scientific®) and the TFL (Soltive SuperPulsed Thulium Fibre [SPTF], 60W; Olympus®) were compared. Data on stone‐free rate (SFR) were determined by computed tomography performed on the first postoperative day and presented as absence of stone fragments, no fragments larger than 2 mm, or no fragments larger than 4 mm. Results: A total of 100 patients met the inclusion criteria, 51 mini‐PCNLs with the Ho:YAG laser and 49 with the SPTF laser. No significant differences in demographics or stone characteristics were detected between the two groups. The Ho:YAG laser utilised less energy and time, resulting in higher ablation efficiency (P < 0.05) and less total operating time (P < 0.05). Overall, there was no difference in SFR in any category between the Ho:YAG group and the SPTF group (no fragments: relative risk [RR] 0.81, 95% confidence interval [CI] 0.59–1.12, P = 0.21; fragments <2 mm: RR 0.86, 95% CI 0.67–1.10, P = 0.23; fragments <4 mm: RR 0.96, 95% CI 0.80–1.15, P = 0.67). Conclusions: Although we observed an equivalent postoperative SFR, this study supports a shorter operating time and greater intra‐operative laser efficiency with the Ho:YAG laser over the SPTF laser in mini‐PCNL. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Hydrogen in magnetite from asteroid Ryugu.
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Aléon, J., Mostefaoui, S., Bureau, H., Vangu, D., Khodja, H., Nagashima, K., Kawasaki, N., Abe, Y., Alexander, C. M. O'D., Amari, S., Amelin, Y., Bajo, K., Bizzarro, M., Bouvier, A., Carlson, R. W., Chaussidon, M., Choi, B.‐G., Dauphas, N., Davis, A. M., and Di Rocco, T.
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SECONDARY ion mass spectrometry ,MAGNETITE crystals ,WATER harvesting ,MAGNETITE ,SOLAR system - Abstract
In order to gain insights on the conditions of aqueous alteration on asteroid Ryugu and the origin of water in the outer solar system, we developed the measurement of water content in magnetite at the micrometer scale by secondary ion mass spectrometry (NanoSIMS) and determined the H and Si content of coarse‐grained euhedral magnetite grains (polyhedral magnetite) and coarse‐grained fibrous (spherulitic) magnetite from the Ryugu polished section A0058‐C1001. The hydrogen content in magnetite ranges between ~900 and ~3300 wt ppm equivalent water and is correlated with the Si content. Polyhedral magnetite has low and homogenous silicon and water content, whereas fibrous magnetite shows correlated Si and water excesses. These excesses can be explained by the presence of hydrous Si‐rich amorphous nanoinclusions trapped during the precipitation of fibrous magnetite away from equilibrium and testify that fibrous magnetite formed from a hydrous gel with possibly more than 20 wt% water. An attempt to determine the water content in sub‐μm framboids indicates that additional calibration and contamination issues must be addressed before a safe conclusion can be drawn, but hints at elevated water content as well. The high water content in fibrous magnetite, expected to be among the first minerals to crystallize at low water–rock ratio, points to the control of water content by local conditions of magnetite precipitation rather than large‐scale alteration conditions. Systematic lithological variations associated with water‐rich and water‐poor magnetite suggest that the global context of alteration may be better understood if local water concentrations are compared with millimeter‐scale distribution of the various morphologies of magnetite. Finally, the high water content in the magnetite precursor gel indicates that the initial O isotopic composition in alteration water must not have been very different from that of the earliest magnetite crystals. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Nature of self-diffusion in two-dimensional fluids
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Choi, B, Han, KH, Kim, C, Talkner, P, Kidera, A, and Lee, EK
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Fluids & Plasmas ,Physical Sciences - Abstract
© 2017 The Author(s). Published by IOP Publishing Ltd on behalf of Deutsche Physikalische Gesellschaft. Self-diffusion in a two-dimensional simple fluid is investigated by both analytical and numerical means. We investigate the anomalous aspects of self-diffusion in two-dimensional fluids with regards to the mean square displacement, the time-dependent diffusion coefficient, and the velocity autocorrelation function (VACF) using a consistency equation relating these quantities. We numerically confirm the consistency equation by extensive molecular dynamics simulations for finite systems, corroborate earlier results indicating that the kinematic viscosity approaches a finite, non-vanishing value in the thermodynamic limit, and establish the finite size behavior of the diffusion coefficient. We obtain the exact solution of the consistency equation in the thermodynamic limit and use this solution to determine the large time asymptotics of the mean square displacement, the diffusion coefficient, and the VACF. An asymptotic decay law of the VACF resembles the previously known self-consistent form, 1/(t√1nt, however with a rescaled time.
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- 2017
16. Development and Progression of Interstitial Lung Disease in COPDGene
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Rose, J.A., primary, Cutting, C., additional, Tukpah, A.-M.C., additional, Wada, N., additional, Nishino, M., additional, Lynch, D.A., additional, Kalra, S., additional, Moll, M., additional, Choi, B., additional, Washko, G.R., additional, Silverman, E.K., additional, Cho, M.H., additional, Hatabu, H., additional, Putman, R.K., additional, and Hunninghake, G.M., additional
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- 2024
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17. Proteomic Risk Score of Accelerated Decline Lung Function Trajectory and Future Respiratory Morbidity and Mortality
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Liu, G.Y.-H., primary, Perry, A.S., additional, Washko, G.R., additional, Farber-Eger, E., additional, Colangelo, L.A., additional, Sheng, Q., additional, Wells, Q., additional, Huang, X., additional, Thyagarajan, B., additional, Guan, W., additional, Alexandria, S.J., additional, San Jose Estepar, R., additional, Bowler, R.P., additional, Esposito, A.J., additional, Khan, S.S., additional, Shah, R.V., additional, Choi, B., additional, and Kalhan, R., additional
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- 2024
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18. Visual and Quantitative Predictors of Interstitial Lung Abnormality Progression in COPDGene
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Putman, R.K., primary, Choi, B., additional, Rose, J.A., additional, Cutting, C., additional, Tukpah, A.-M.C., additional, San Jose Estepar, R., additional, Hino, T., additional, Hata, A., additional, Nishino, M., additional, Silverman, E.K., additional, Cho, M.H., additional, Washko, G.R., additional, Hatabu, H., additional, and Hunninghake, G.M., additional
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- 2024
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19. Proteomic Signature of Quantitative Interstitial Abnormalities in COPDGene and Cardia Lung Study
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Choi, B., primary, Liu, G.Y.-H., additional, San Jose Estepar, R., additional, Putman, R.K., additional, Hunninghake, G.M., additional, Cho, M.H., additional, Kalhan, R., additional, and Washko, G.R., additional
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- 2024
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20. Job Types Associated With Worse Pulmonary Function and CT Interstitial Changes in the Coronary Artery Risk Development in Young Adults (CARDIA) Lung Study
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Lee, C.T., primary, Strek, M.E., additional, Colangelo, L., additional, Washko, G.R., additional, San Jose Estepar, R., additional, Choi, B., additional, Liu, G.Y.-H., additional, Esposito, A.J., additional, Press, V.G., additional, and Kalhan, R., additional
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- 2024
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21. CT Characteristics of COPD Patients With Impaired Diffusion Capacity; Implications for COPD-pulmonary Hypertension Phenotyping
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Johnson, S.W., primary, Pistenmaa, C.L., additional, Diaz, A.A., additional, Choi, B., additional, Nardelli, P., additional, San Jose Estepar, R., additional, Waxman, A.B., additional, Wan, E., additional, Washko, G.R., additional, and Rahaghi, F.N., additional
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- 2024
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22. Quantitative assessment of graded burn wounds using a commercial and research grade laser speckle imaging (LSI) system
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Ponticorvo, A, Rowland, R, Yang, B, Lertsakdadet, B, Crouzet, C, Bernal, N, Choi, B, and Durkin, AJ
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Burns ,perfusion ,laser speckle imaging - Abstract
Burn wounds are often characterized by injury depth, which then dictates wound management strategy. While most superficial burns and full thickness burns can be diagnosed through visual inspection, clinicians experience difficulty with accurate diagnosis of burns that fall between these extremes. Accurately diagnosing burn severity in a timely manner is critical for starting the appropriate treatment plan at the earliest time points to improve patient outcomes. To address this challenge, research groups have studied the use of commercial laser Doppler imaging (LDI) systems to provide objective characterization of burn-wound severity. Despite initial promising findings, LDI systems are not commonplace in part due to long acquisition times that can suffer from artifacts in moving patients. Commercial LDI systems are being phased out in favor of laser speckle imaging (LSI) systems that can provide similar information with faster acquisition speeds. To better understand the accuracy and usefulness of commercial LSI systems in burn-oriented research, we studied the performance of a commercial LSI system in three different sample systems and compared its results to a research-grade LSI system in the same environments. The first sample system involved laboratory measurements of intralipid (1%) flowing through a tissue simulating phantom, the second preclinical measurements in a controlled burn study in which wounds of graded severity were created on a Yorkshire pig, and the third clinical measurements involving a small sample of clinical patients. In addition to the commercial LSI system, a research grade LSI system that was designed and fabricated in our labs was used to quantitatively compare the performance of both systems and also to better understand the "Perfusion Unit" output of commercial systems.
- Published
- 2017
23. Risks of occupational mental disorders in Korean civil servants (2009–18).
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Choi, B-Y, Min, K-B, Ryoo, S-W, and Min, J-Y
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WORKERS' compensation claims , *CIVIL service , *PHYSICIANS , *MENTAL illness , *ENVIRONMENTAL medicine - Abstract
Background Previous studies have suggested that firefighters, police officers and civil servants in the education sector, particularly in Western countries, are vulnerable to mental stress and disorders; however, evidence for this association in South Korea is lacking. Aims This study aimed to identify whether firefighters, police officers and teachers are at a higher risk for occupational mental health disorders. Methods We used workers' compensation claims from civil servants (2009–18). Our target population comprised 46 209 civil servants (9009 civil servants in administrative and technical positions, 23 107 police officers, 4417 firefighters and 8676 civil servants in the educational sector). Occupational and environmental medicine physicians and medical doctors defined and confirmed mental disorders. We conducted Cox proportional hazards regression analyses to evaluate civil servants' risk of occupational mental health disorders. Results Compared with the civil servants in administrative and technical positions, civil servants in the education sector (hazard ratio [HR] = 2.16; 95% confidence interval [CI]:1.65–2.84) showed a statistically significant increased risk of mental disorders; conversely, firefighters did not (HR = 0.80; 95% CI 0.51–1.27). Police officers had a significantly decreased mental disorder risk compared with civil servants in administrative and technical positions (HR = 0.17; 95% CI 0.11–0.25). Conclusions The risk of occupational mental health disorders was higher in civil servants in the education sector but lower in police officers and firefighters than civil servants in administrative and technical positions. Further studies on civil servants' mental health awareness are required to confirm our results. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Improved tolerability of neratinib in patients with HER2-positive early-stage breast cancer: the CONTROL trial
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Carcas, L., Castrellon, A., Chan, D., Cheong, K., Choi, B., Coleman, M., Conlin, A., Dichmann, R., Ellison, D., Erickson, N., Gore, I., Hansen, V., Huang, D., Hufnagel, D., Kass, F., Kendall, S.D., Kozloff, M., Lawler, W., Nahum, K.D., Pistilli, B., Reyes, E., Seeger, J., Somer, R., Chiu, E. Tan, Thomas, G., Tkaczuk, K., Vaziri, I., Wade, J., Wilkinson, M., Barcenas, C.H., Hurvitz, S.A., Di Palma, J.A., Bose, R., Chien, A.J., Iannotti, N., Marx, G., Brufsky, A., Litvak, A., Ibrahim, E., Alvarez, R.H., Ruiz-Borrego, M., Chan, N., Manalo, Y., Kellum, A., Trudeau, M., Thirlwell, M., Garcia Saenz, J., Hunt, D., Bryce, R., McCulloch, L., Rugo, H.S., Tripathy, D., and Chan, A.
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- 2020
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25. Enhanced Endurance Characteristics in High Performance 16nm Selector Only Memory (SOM)
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Park, I.-M., primary, Lee, K. W., additional, Park, J.-H., additional, Song, S. J., additional, Kim, T. Y., additional, Wu, Z., additional, Lee, W. J., additional, Choi, B. D., additional, Jeong, Y. J., additional, Oh, S. C., additional, Park, K., additional, Kuh, B. J., additional, Song, Y. J., additional, Shin, Y. G., additional, and Song, J. H., additional
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- 2023
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26. Ten-year major clinical outcomes between first- and second-generation Drug-Eluting Stents in unstable angina patients underwent Percutaneous Coronary Intervention
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Rha, S W, primary, Choi, S Y, additional, Choi, B G, additional, Byun, J K, additional, Cha, J, additional, Hyun, S, additional, Park, S, additional, Kim, J B, additional, and Choi, C U, additional
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- 2023
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27. Pre-test probability for coronary artery disease in patients with chest pain based on machine learning techniques
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Rha, S W, primary, Choi, B G, additional, Choi, S Y, additional, Byun, J K, additional, Cha, J, additional, Hyun, S, additional, Park, S, additional, Kim, J B, additional, and Choi, C U, additional
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- 2023
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28. A predictors for 10-year mortality and clinical events in patients with chronic coronary total occlusion lesion
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Kim, K, primary, Choi, B G, additional, and Rha, S W, additional
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- 2023
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29. A long-term prognostic factor for cardiovascular risk in patients with chest pain without diabetes mellitus and significant coronary stenosis
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Rha, S W, primary, Choi, B G, additional, Choi, S Y, additional, Byun, J K, additional, Cha, J, additional, Hyun, S, additional, Park, S, additional, Kim, J B, additional, and Choi, C U, additional
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- 2023
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30. First Operation of an Ungated Diamond Field-Emission Array Cathode in a L-Band Radiofrequency Electron Source
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Piot, P., Brau, C. A., Choi, B. K., Blomberg, B., Gabella, W. E., Ivanov, B., Jarvis, J., Mendenhall, M. H., Mihalcea, D., Panuganti, S., Prieto, P., and Reid, J.
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Physics - Accelerator Physics - Abstract
We report on the first successful operation of a field-emitter-array cathode in a conventional L-band radio-frequency electron source. The cathode consisted of an array of $\sim 10^6$ diamond diamond tips on pyramids. Maximum current on the order of 15~mA were reached and the cathode did not show appreciable signs of fatigue after weeks of operation. The measured Fowler-Nordheim characteristics, transverse beam density, and current stability are discussed. Numerical simulations of the beam dynamics are also presented., Comment: 4 pages, 7 figures; preprint submitted to Applied Physics Letters
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- 2014
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31. Observation and applications of single-electron charge signals in the XENON100 experiment
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Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, A., Brown, E., Bruenner, S., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Itay, R., Kaether, F., Kessler, G., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Messina, M., Molinario, A., Naganoma, J., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Piastra, F., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Physics - Instrumentation and Detectors ,Astrophysics - Instrumentation and Methods for Astrophysics ,High Energy Physics - Experiment - Abstract
The XENON100 dark matter experiment uses liquid xenon in a time projection chamber (TPC) to measure xenon nuclear recoils resulting from the scattering of dark matter Weakly Interacting Massive Particles (WIMPs). In this paper, we report the observation of single-electron charge signals which are not related to WIMP interactions. These signals, which show the excellent sensitivity of the detector to small charge signals, are explained as being due to the photoionization of impurities in the liquid xenon and of the metal components inside the TPC. They are used as a unique calibration source to characterize the detector. We explain how we can infer crucial parameters for the XENON100 experiment: the secondary-scintillation gain, the extraction yield from the liquid to the gas phase and the electron drift velocity., Comment: 16 pages, 8 figures. Accepted for publication in Journal of Physics G: Nuclear and Particle Physics
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- 2013
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32. High-Capacity Capacitor Charging Power Supply for a Pulse Modulator
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Kim, D. S., Lee, B. K., Park, S. S., Choi, B. H., and Lee, S. H.
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- 2020
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33. Utility of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) to non-invasively diagnose burn depth in a porcine model
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Burmeister, DM, Ponticorvo, A, Yang, B, Becerra, SC, Choi, B, Durkin, AJ, and Christy, RJ
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Emergency & Critical Care Medicine ,Clinical Sciences - Abstract
Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter (μs) and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time.
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- 2015
34. Acute discrimination between superficial-partial and deep-partial thickness burns in a preclinical model with laser speckle imaging
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Crouzet, C, Nguyen, JQ, Ponticorvo, A, Bernal, NP, Durkin, AJ, and Choi, B
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Clinical Sciences ,Emergency & Critical Care Medicine - Abstract
A critical need exists for a robust method that enables early discrimination between superficial-partial and deep-partial thickness burn wounds. In this study, we report on the use of laser speckle imaging (LSI), a simple, non-invasive, optical imaging modality, to measure acute blood flow dynamics in a preclinical burn model. We used a heated brass comb to induce burns of varying severity to nine rats and collected raw speckle reflectance images over the course of three hours after burn. We induced a total of 12 superficial-partial and 18 deep-partial thickness burn wounds. At 3 h after burn we observed a 28% and 44% decrease in measured blood flow for superficial-partial and deep-partial thickness burns, respectively, and that these reductions were significantly different (p = 0.00007). This preliminary data suggests the potential role of LSI in the clinical management of burn wounds.
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- 2015
35. Clinical embodiments of laser speckle imaging for real- time blood-flow monitoring
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Choi, B
- Abstract
Laser Speckle Imaging (LSI) is used widely in preclinical studies of blood flow, especially in neurobiology. However, clinical application of LSI remains underexplored. Here, I describe our experiences in developing clinic-friendly embodiments of LSI. © 2015 OSA.
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- 2015
36. Talaporfin sodium-mediated photodynamic therapy alone and in combination with pulsed dye laser on cutaneous vasculature
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Kelly, KM, Moy, WJ, Moy, AJ, Lertsakdadet, BS, Moy, JJ, Nguyen, E, Nguyen, A, Osann, KE, and Choi, B
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Clinical Sciences ,Oncology and Carcinogenesis ,Dermatology & Venereal Diseases - Published
- 2015
37. The neutron background of the XENON100 dark matter experiment
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Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, A., Brown, E., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Kaether, F., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Messina, M., Molinario, A., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., ScottoLavina, L., Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Tziaferi, E., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Instrumentation and Detectors - Abstract
The XENON100 experiment, installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), aims to directly detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off xenon nuclei. This paper presents a study on the nuclear recoil background of the experiment, taking into account neutron backgrounds from ($\alpha$,n) and spontaneous fission reactions due to natural radioactivity in the detector and shield materials, as well as muon-induced neutrons. Based on Monte Carlo simulations and using measured radioactive contaminations of all detector components, we predict the nuclear recoil backgrounds for the WIMP search results published by the XENON100 experiment in 2011 and 2012, 0.11$^{+0.08}_{-0.04}$ events and 0.17$^{+0.12}_{-0.07}$ events, respectively, and conclude that they do not limit the sensitivity of the experiment.
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- 2013
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38. Response of the XENON100 Dark Matter Detector to Nuclear Recoils
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The XENON100 Collaboration, Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, A., Brown, E., Bruenner, S., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Geis, C., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Itay, R., Kaether, F., Kessler, G., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Messina, M., Molinario, A., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., Weinheimer, C., Schuhmacher, H., and Wiegel, B.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
Results from the nuclear recoil calibration of the XENON100 dark matter detector installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), Italy are presented. Data from measurements with an external 241AmBe neutron source are compared with a detailed Monte Carlo simulation which is used to extract the energy dependent charge-yield Qy and relative scintillation efficiency Leff. A very good level of absolute spectral matching is achieved in both observable signal channels - scintillation S1 and ionization S2 - along with agreement in the 2-dimensional particle discrimination space. The results confirm the validity of the derived signal acceptance in earlier reported dark matter searches of the XENON100 experiment., Comment: 10 pages, 10 figures. Matches version accepted by PRD. Contains revised representation of expected WIMP event signature. Conclusions remain unaffected
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- 2013
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39. Limits on spin-dependent WIMP-nucleon cross sections from 225 live days of XENON100 data
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XENON100 collaboration, Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, A., Brown, E., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Kaether, F., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Lellouch, D., Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Messina, M., Molinario, A., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Cosmology and Extragalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology - Abstract
We present new experimental constraints on the elastic, spin-dependent WIMP-nucleon cross section using recent data from the XENON100 experiment, operated in the Laboratori Nazionali del Gran Sasso in Italy. An analysis of 224.6 live days x 34 kg of exposure acquired during 2011 and 2012 revealed no excess signal due to axial-vector WIMP interactions with 129-Xe and 131-Xe nuclei. This leads to the most stringent upper limits on WIMP-neutron cross sections for WIMP masses above 6 GeV, with a minimum cross section of 3.5 x 10^{-40} cm^2 at a WIMP mass of 45 GeV, at 90% confidence level., Comment: 5 pages, 3 figures; corrected caption of figure 3
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- 2013
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40. The distributed Slow Control System of the XENON100 Experiment
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Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Behrens, A., Beltrame, P., Bokeloh, K., Brown, E., Bruno, G. M., Budnik, R., Calloch, M. Le, Cardoso, J. M., Chen, W. -T., Choi, B., Contreras, H., Cussonneau, J. -P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Giboni, K. -L., Goetzke, L., Grignon, C., Gross, E., Hampel, W., McKinsey, D. N., Kish, A., Lamblin, J., Lang, R. F., Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Manzur, A., Undagoitia, T. Marrodán, Massoli, F. V., Mei, Y., Fernandez, A. J. Melgarejo, Meng, Y., Molinario, A., Nativ, E., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Patricio, J. V., Persiani, R., Plante, G., Priel, N., Ribeiro, A. C. C., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Instrumentation and Detectors - Abstract
The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, was designed to search for evidence of dark matter interactions inside a volume of liquid xenon using a dual-phase time projection chamber. This paper describes the Slow Control System (SCS) of the experiment with emphasis on the distributed architecture as well as on its modular and expandable nature. The system software was designed according to the rules of Object-Oriented Programming and coded in Java, thus promoting code reusability and maximum flexibility during commissioning of the experiment. The SCS has been continuously monitoring the XENON100 detector since mid 2008, remotely recording hundreds of parameters on a few dozen instruments in real time, and setting emergency alarms for the most important variables., Comment: 12 pages, 4 figures
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- 2012
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41. Measurement of the Scintillation Yield of Low-Energy Electrons in Liquid Xenon
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Aprile, E., Budnik, R., Choi, B., Contreras, H. A., Giboni, K. -L., Goetzke, L. W., Koglin, J. E., Lang, R. F., Lim, K. E., Fernandez, A. J. Melgarejo, Persiani, R., Plante, G., and Rizzo, A.
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Instrumentation and Detectors - Abstract
We have measured the energy dependence of the liquid xenon (LXe) scintillation yield of electrons with energy between 2.1 and 120.2keV, using the Compton coincidence technique. A LXe scintillation detector with a very high light detection efficiency was irradiated with 137Cs {\gamma} rays and the energy of the Compton-scattered {\gamma} rays was measured with a high-purity germanium (HPGe) detector placed at different scattering angles. The excellent energy resolution of the HPGe detector allows the selection of events with Compton electrons of known energy in the LXe detector. We find that the scintillation yield initially increases as the electron energy decreases from 120 keV to about 60keV but then decreases by about 30% from 60keV to 2keV. The measured scintillation yield was also measured with conversion electrons from the 32.1 keV and 9.4 keV transitions of the 83mKr isomer, used as an internal calibration source. We find that the scintillation yield of the 32.1 keV transition is compatible with that obtained from the Compton coincidence measurement. On the other hand, the yield for the 9.4keV transition is much higher than that measured for a Compton electron of the same energy. We interpret the enhancement in the scintillation yield as due to the enhanced recombination rate in the presence of Xe ions left from the 32.1 keV transition, which precedes the 9.4 keV one by 220 ns, on average., Comment: 14 pages, 8 figures
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- 2012
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42. Comment on 'On the subtleties of searching for dark matter with liquid xenon detectors'
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The XENON Collaboration, Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, E., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Cline, D., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Kaether, F., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Molinario, A., Nativ, E., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Cosmology and Extragalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology - Abstract
In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that XENON100's upper limits on spin-independent WIMP-nucleon cross sections for WIMP masses below 10 GeV "may be understated by one order of magnitude or more". Having performed a similar, though more detailed analysis prior to the submission of our new result (arXiv:1207.5988), we do not confirm these findings. We point out the rationale for not considering the described effect in our final analysis and list several potential problems with his study., Comment: 3 pages, no figures
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- 2012
43. Dark Matter Results from 225 Live Days of XENON100 Data
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XENON100 Collaboration, Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Bauermeister, B., Behrens, A., Beltrame, P., Bokeloh, K., Brown, E., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Cline, D., Colijn, A. P., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Ghag, C., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Kaether, F., Kettling, H., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Fernandez, A. J. Melgarejo, Meng, Y., Molinario, A., Nativ, E., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Cosmology and Extragalactic Astrophysics ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Physics - Instrumentation and Detectors - Abstract
We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) for 13 months during 2011 and 2012. XENON100 features an ultra-low electromagnetic background of (5.3 \pm 0.6) \times 10^-3 events (kg day keVee)^-1 in the energy region of interest. A blind analysis of 224.6 live days \times 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the pre-defined nuclear recoil energy range of 6.6-30.5 keVnr are consistent with the background expectation of (1.0 \pm 0.2) events. A Profile Likelihood analysis using a 6.6-43.3 keVnr energy range sets the most stringent limit on the spin-independent elastic WIMP-nucleon scattering cross section for WIMP masses above 8 GeV/c^2, with a minimum of 2 \times 10^-45 cm^2 at 55 GeV/c^2 and 90% confidence level., Comment: 6 pages, 5 figures. Matches version accepted by PRL. Includes limits up to 10 TeV/c^2, published as supplementary material: http://prl.aps.org/supplemental/PRL/v109/i18/e181301 Please cite high mass limits as "Phys. Rev. Lett. 109, 181301 (2012), online supplementary material."
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- 2012
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44. Measurement of the Quantum Efficiency of Hamamatsu R8520 Photomultipliers at Liquid Xenon Temperature
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Aprile, E., Beck, M., Bokeloh, K., Budnik, R., Choi, B., Contreras, H. A., Giboni, K. -L., Goetzke, L. W., Lang, R. F., Lim, K. E., Fernandez, A. J. Melgarejo, Plante, G., Rizzo, A., Shagin, P., and Weinheimer, C.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Instrumentation and Detectors - Abstract
Vacuum ultraviolet light sensitive photomultiplier tubes directly coupled to liquid xenon are being used to efficiently detect the 178 nm scintillation light in a variety of liquid xenon based particle detectors. Good knowledge of the performance of these photomultipliers under cryogenic conditions is needed to properly characterize these detectors. Here, we report on measurements of the quantum efficiency of Hamamatsu R8520 photomultipliers, used in the XENON Dark Matter Experiments. The quantum efficiency measurements at room temperature agree with the values provided by Hamamatsu. At low temperatures, between 160K and 170K, the quantum efficiency increases by $\sim5-11$% relative to the room temperature values.
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- 2012
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45. Analysis of the XENON100 Dark Matter Search Data
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The XENON100 Collaboration, Aprile, E., Alfonsi, M., Arisaka, K., Arneodo, F., Balan, C., Baudis, L., Behrens, A., Beltrame, P., Bokeloh, K., Brown, E., Bruno, G., Budnik, R., Cardoso, J. M. R., Chen, W. -T., Choi, B., Cline, D. B., Contreras, H., Cussonneau, J. P., Decowski, M. P., Duchovni, E., Fattori, S., Ferella, A. D., Fulgione, W., Gao, F., Garbini, M., Giboni, K. -L., Goetzke, L. W., Grignon, C., Gross, E., Hampel, W., Kish, A., Lamblin, J., Landsman, H., Lang, R. F., Calloch, M. Le, Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Massoli, F. V., Mei, Y., Fernandez, A. J. Melgarejo, Meng, Y., Molinario, A., Nativ, E., Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Priel, N., Rizzo, A., Rosendahl, S., Santos, J. M. F. dos, Sartorelli, G., Schreiner, J., Schumann, M., Lavina, L. Scotto, Scovell, P. R., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Instrumentation and Detectors - Abstract
The XENON100 experiment, situated in the Laboratori Nazionali del Gran Sasso, aims at the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs), based on their interactions with xenon nuclei in an ultra low background dual-phase time projection chamber. This paper describes the general methods developed for the analysis of the XENON100 data. These methods have been used in the 100.9 and 224.6 live days science runs from which results on spin-independent elastic, spin-dependent elastic and inelastic WIMP-nucleon cross-sections have already been reported., Comment: 18 pages, 17 figures, information for the 224.6 live days run included
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- 2012
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46. The XENON100 Dark Matter Experiment
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XENON100 Collaboration, Aprile, E., Arisaka, K., Arneodo, F., Askin, A., Baudis, L., Behrens, A., Brown, E., Cardoso, J. M. R., Choi, B., Cline, D., Fattori, S., Ferella, A. D., Giboni, K. L., Kish, A., Lam, C. W., Lang, R. F., Lim, K. E., Lopes, J. A. M., Undagoitia, T. Marrodan, Mei, Y., Fernandez, A. J. Melgarejo, Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Plante, G., Ribeiro, A. C. C., Santorelli, R., Santos, J. M. F. dos, Schumann, M., Shagin, P., Teymourian, A., Tziaferi, E., Wang, H., and Yamashita, M.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
The XENON100 dark matter experiment uses liquid xenon (LXe) in a time projection chamber (TPC) to search for Xe nuclear recoils resulting from the scattering of dark matter Weakly Interacting Massive Particles (WIMPs). In this paper we present a detailed description of the detector design and present performance results, as established during the commissioning phase and during the first science runs. The active target of XENON100 contains 62 kg of LXe, surrounded by an LXe veto of 99 kg, both instrumented with photomultiplier tubes (PMTs) operating inside the liquid or in Xe gas. The LXe target and veto are contained in a low-radioactivity stainless steel vessel, embedded in a passive radiation shield. The experiment is installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), Italy and has recently published results from a 100 live-days dark matter search. The ultimate design goal of XENON100 is to achieve a spin-independent WIMP-nucleon scattering cross section sensitivity of \sigma = 2x10^-45 cm^2 for a 100 GeV/c^2 WIMP., Comment: 23 pages, 27 figures; version accepted by journal
- Published
- 2011
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47. Implications on Inelastic Dark Matter from 100 Live Days of XENON100 Data
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XENON100 Collaboration, Aprile, E., Arisaka, K., Arneodo, F., Askin, A., Baudis, L., Behrens, A., Bokeloh, K., Brown, E., Bruch, T., Bruno, G., Cardoso, J. M. R., Chen, W. -T., Choi, B., Cline, D., Duchovni, E., Fattori, S., Ferella, A. D., Gao, F., Giboni, K. -L., Gross, E., Kish, A., Lam, C. W., Lamblin, J., Lang, R. F., Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodán, Mei, Y., Fernandez, A. J. Melgarejo, Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Ribeiro, A. C. C., Santorelli, R., Santos, J. M. F. dos, Sartorelli, G., Schumann, M., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
The XENON100 experiment has recently completed a dark matter run with 100.9 live-days of data, taken from January to June 2010. Events in a 48kg fiducial volume in the energy range between 8.4 and 44.6 keVnr have been analyzed. A total of three events have been found in the predefined signal region, compatible with the background prediction of (1.8 \pm 0.6) events. Based on this analysis we present limits on the WIMP-nucleon cross section for inelastic dark matter. With the present data we are able to rule out the explanation for the observed DAMA/LIBRA modulation as being due to inelastic dark matter scattering off iodine at a 90% confidence level., Comment: 3 pages, 3 figures
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- 2011
- Full Text
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48. New Measurement of the Scintillation Efficiency of Low-Energy Nuclear Recoils in Liquid Xenon
- Author
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Plante, G., Aprile, E., Budnik, R., Choi, B., Giboni, K. -L., Goetzke, L. W., Lang, R. F., Lim, K. E., and Fernandez, A. J. Melgarejo
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Nuclear Experiment ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
Particle detectors that use liquid xenon (LXe) as detection medium are among the leading technologies in the search for dark matter weakly interacting massive particles (WIMPs). A key enabling element has been the low-energy detection threshold for recoiling nuclei produced by the interaction of WIMPs in LXe targets. In these detectors, the nuclear recoil energy scale is based on the LXe scintillation signal and thus requires knowledge of the relative scintillation efficiency of nuclear recoils, Leff. The uncertainty in Leff at low energies is the largest systematic uncertainty in the reported results from LXe WIMP searches at low masses. In the context of the XENON Dark Matter project, a new LXe scintillation detector has been designed and built specifically for the measurement of Leff at low energies, with an emphasis on maximizing the scintillation light detection efficiency to obtain the lowest possible energy threshold. We report new measurements of Leff at low energies performed with this detector. Our results suggest a Leff which slowly decreases with energy, from 0.144 +/- 0.009 at 15 keV down to 0.088 +0.014 -0.015 at 3 keV., Comment: 14 pages, 13 figures
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- 2011
- Full Text
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49. Dark Matter Results from 100 Live Days of XENON100 Data
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XENON100 Collaboration, Aprile, E., Arisaka, K., Arneodo, F., Askin, A., Baudis, L., Behrens, A., Bokeloh, K., Brown, E., Bruch, T., Bruno, G., Cardoso, J. M. R., Chen, W. -T., Choi, B., Cline, D., Duchovni, E., Fattori, S., Ferella, A. D., Gao, F., Giboni, K. -L., Gross, E., Kish, A., Lam, C. W., Lamblin, J., Lang, R. F., Levy, C., Lim, K. E., Lin, Q., Lindemann, S., Lindner, M., Lopes, J. A. M., Lung, K., Undagoitia, T. Marrodan, Mei, Y., Fernandez, A. J. Melgarejo, Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Persiani, R., Plante, G., Ribeiro, A. C. C., Santorelli, R., Santos, J. M. F. dos, Sartorelli, G., Schumann, M., Selvi, M., Shagin, P., Simgen, H., Teymourian, A., Thers, D., Vitells, O., Wang, H., Weber, M., and Weinheimer, C.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Experiment - Abstract
We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows to select only the innermost 48 kg as ultra-low background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in a pre-defined signal region with an expected background of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic WIMP-nucleon scattering cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90% confidence level., Comment: 5 pages, 5 figures; matches accepted version
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- 2011
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50. Material screening and selection for XENON100
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XENON100 Collaboration, Aprile, E., Arisaka, K., Arneodo, F., Askin, A., Baudis, L., Behrens, A., Bokeloh, K., Brown, E., Cardoso, J. M. R., Choi, B., Cline, D., Fattori, S., Ferella, A. D., Giboni, K. L., Kish, A., Lam, C. W., Lamblin, J., Lang, R. F., Lim, K. E., Lopes, J. A. M., Undagoitia, T. Marrodan, Mei, Y., Fernandez, A. J. Melgarejo, Ni, K., Oberlack, U., Orrigo, S. E. A., Pantic, E., Plante, G., Ribeiro, A. C. C, Santorelli, R., Santos, J. M. F. dos, Schumann, M., Shagin, P., Teymourian, A., Thers, D., Tziaferi, E., Wang, H., Weinheimer, C., Laubenstein, M., and Nisi, S.
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Physics - Instrumentation and Detectors - Abstract
Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This Dark Matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors (HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been applied for a few low mass plastic samples. Detailed tables with the radioactive contaminations of all screened samples are presented, together with the implications for XENON100., Comment: 8 pages, 1 figure
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- 2011
- Full Text
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