Article
Chemistry, Multidisciplinary
S. Tkachenko, P. Arhipov, I Gerasymov, E. Galenin, A. Shaposhnyk, O. Hryshyna, P. Mateychenko, Y. Boyaryntseva, O. Zelenskaya, K. Lebbou, B. Grynyov, O. Sidletskiy
Summary: The feasibility of growing silicate single crystals from melt using Mo or W crucibles in crystallizers with graphite heaters is evaluated, with examples shown using YSO:Ce and LaGPS:Ce scintillation crystals. The use of cheaper molybdenum (Mo) or tungsten (W) crucibles has enabled the growth of bulk YSO:Ce and LaGPS:Ce crystals for the first time. The optical and scintillation parameters of the obtained crystals are compared to those grown by the conventional Czochralski process in Ir crucibles, and further optimization of technological processes is discussed.
Article
Chemistry, Multidisciplinary
Zhongjun Xue, Lu Chen, Shuwen Zhao, Fan Yang, Ran An, Linwei Wang, Yi-Yang Sun, He Feng, Dongzhou Ding
Summary: By co-doping with aluminum ions (Al3+), the scintillation properties of LYSO:Ce crystals have been improved, resulting in an increased image signal-to-noise ratio and enabling more precise disease diagnosis.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Sudesna Roy, Charles Brecher, Helmut Lingertat, Vinod Sarin
Summary: This study investigates the behavior of lutetium oxyorthosilicate under sintering conditions, revealing its decomposition in highly reducing atmospheres and confirming the results through various analytical techniques.
Article
Optics
Chansun Park, Sangsu Kim, Wonhi Lee, Chanho Kim, Shinhaeng Cho, Jung-Yeol Yeom
Summary: Chemical polishing treatment using anhydrous phosphoric acid improved the light output and energy resolution of Ce-doped GAGG ceramic, making it a cost-effective alternative to mechanical polishing for small or complex shaped scintillators.
Article
Materials Science, Multidisciplinary
Jiajia Cai, Yau-yuen Yeung
Summary: The study reveals the effect of Ca codoping in enhancing the light yield and shortening the decay time of Lu2SiO5:Ce through first-principles calculations. The formation of CaLu-VO complex defects favors the dissociation of CeLu-VO, suppressing the nonradiative decay of Ce via VO and thus increasing the light yield. Additionally, the downward shift of the Fermi level and the combination effect with Ca result in the observation of Ce4+ ions and a decrease in the electron trap depth of VO, leading to accelerated trapping/detrapping rates and shortened decay time. This research provides insights into the mechanisms for tuning properties of optical materials through codoping.
Article
Chemistry, Physical
Valentyn Laguta, Lubomir Havlak, Vladimir Babin, Jan Barta, Jan Pejchal, Martin Nikl
Summary: Lutetium oxyorthosilicate (LSO) and pyrosilicate (LPS) activated by Ce3+ or Pr3+ are effective scintillation materials for X-ray and γ-ray detection. Co-doping with Ca2+ and Al3+ can enhance their performance by promoting the conversion of Ce3+ to Ce4+ and inducing lattice defects.
Article
Optics
M. V. Belov, S. A. Koutovoi, V. A. Kozlov, N. V. Pestovskii, S. Yu. Savinov, A. I. Zagumennyi, Yu. D. Zavartsev, M. V. Zavertyaev
Summary: This study investigates the photoluminescence (PL) of Lu2SiO5 crystal and ceramics with a high concentration of oxygen vacancies. The researchers observed a fairly bright room-temperature ultraviolet PL in both crystal grown from the Lu2Si0.98O4.96 melt and Lu2SiO5 ceramics doped with Ca2+ ions. The spectral and kinetic properties of the observed PL bands in both materials are similar, indicating similar origins of these bands.
JOURNAL OF LUMINESCENCE
(2023)
Article
Physics, Multidisciplinary
M. Belov, Yu D. Zavartsev, M. Zavertyaev, A. Zagumennyi, V. A. Kozlov, S. A. Kutovoi, N. Pestovskii, S. Yu Savinov
Summary: The scintillation parameters of lutetium oxyorthosilicate doped with Ce3+, Y3+, and Ca2+ ions were studied, and the variation in scintillation time due to crystal composition was investigated. This research considers the promising application of this crystalline material in experimental setups of modern accelerator facilities.
BULLETIN OF THE LEBEDEV PHYSICS INSTITUTE
(2022)
Article
Optics
Gurvan Brasse, Remi Soulard, Jean-Louis Doualan, Alain Braud, Abdelmjid Benayad, Patrice Camy
Summary: The study demonstrates the advantages of Tm3+ doping in improving the excitation of Dy3+ ions in CaF2, showing potential for laser applications. Laser modeling results suggest promising laser perspectives around 3 μm, with efficiency levels in the order of 30%, and discuss the saturation of absorption observed in codoped crystals with Dy3+ concentration below 1%.
JOURNAL OF LUMINESCENCE
(2021)
Article
Geosciences, Multidisciplinary
Lei Liu, Y. Jade Morton, Yunxiang Liu
Summary: The convLSTM-L-c model is developed to predict ionospheric irregularities using ROTI maps derived from the global navigation satellite system. The custom-designed loss function improves prediction performance compared to conventional approaches. The model performs well in predicting short-term ionospheric irregularities under geomagnetic active conditions at mid- and high latitudes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Engineering, Aerospace
Dongsheng Zhao, Wang Li, Qianxin Wang, Xin Liu, Chendong Li, Craig M. Hancock, Gethin Wyn Roberts, Kefei Zhang
Summary: A statistical study on the characterization of phase and amplitude scintillation events in the high-latitude region is conducted in this paper. Results show that phase scintillation dominates in most of the high-latitude regions, with stronger intensity in the middle-high latitude region. The duration of scintillation in this region is generally shorter. The occurrence of ionospheric scintillation is influenced by seasonal and diurnal factors as well as space weather parameters such as Ap and IMF.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Geochemistry & Geophysics
Kai Guo, Sreeja Vadakke Veettil, Brian Jerald Weaver, Marcio Aquino
Summary: Ionospheric scintillation involves rapid and random fluctuations in radio frequency signal intensity and phase, especially in high latitudes. This study analyzes GPS scintillation data and proposes a novel approach to mitigate scintillation effects at high latitudes, leading to reduced 3D positioning errors.
JOURNAL OF GEODESY
(2021)
Article
Astronomy & Astrophysics
D. J. Temples, J. McLaughlin, J. Bargemann, D. Baxter, A. Cottle, C. E. Dahl, W. H. Lippincott, A. Monte, J. Phelan
Summary: In this study, a cross-calibration of tritium beta decays and Xe-127 electron-capture decays in a small-scale LXe-TPC was conducted, providing the most precise measurements to date of light and charge yields for the Xe-127 L-shell electron-capture in liquid xenon. A significant discrepancy in the L-shell capture response relative to tritium beta decays was observed, highlighting the importance of taking into account such effects in dark matter searches.
Article
Remote Sensing
J. Sousasantos, M. A. Abdu, E. R. de Paula, A. O. Moraes, L. A. Salles, B. J. Affonso
Summary: The evolution of equatorial plasma bubbles, their symmetric propagation away from the equator over the north/south hemispheres, the asymmetry in vertical plasma drift, and the implications between these phenomena are examples of the results from the conjugate point experiment campaign.
Article
Physics, Particles & Fields
P. Adhikari, R. Ajaj, M. Alpizar-Venegas, P-A Amaudruz, D. J. Auty, M. Batygov, B. Beltran, H. Benmansour, C. E. Bina, J. Bonatt, W. Bonivento, M. G. Boulay, B. Broerman, J. F. Bueno, P. M. Burghardt, A. Butcher, M. Cadeddu, B. Cai, M. Cardenas-Montes, S. Cavuoti, M. Chen, Y. Chen, B. T. Cleveland, J. M. Corning, D. Cranshaw, S. Daugherty, P. DelGobbo, K. Dering, J. DiGioseffo, P. Di Stefano, L. Doria, F. A. Duncan, M. Dunford, E. Ellingwood, A. Erlandson, S. S. Farahani, N. Fatemighomi, G. Fiorillo, S. Florian, T. Flower, R. J. Ford, R. Gagnon, D. Gallacher, P. Garcia Abia, S. Garg, P. Giampa, D. Goeldi, V Golovko, P. Gorel, K. Graham, D. R. Grant, A. Grobov, A. L. Hallin, M. Hamstra, P. J. Harvey, C. Hearns, T. Hugues, A. Ilyasov, A. Joy, B. Jigmeddorj, C. J. Jillings, O. Kamaev, G. Kaur, A. Kemp, I Kochanek, M. Kuzniak, M. Lai, S. Langrock, B. Lehnert, A. Leonhardt, N. Levashko, X. Li, J. Lidgard, T. Lindner, M. Lissia, J. Lock, G. Longo, I Machulin, A. B. McDonald, T. McElroy, T. McGinn, J. B. McLaughlin, R. Mehdiyev, C. Mielnichuk, J. Monroe, P. Nadeau, C. Nantais, C. Ng, A. J. Noble, E. O'Dwyer, G. Oliviero, C. Ouellet, S. Pal, P. Pasuthip, S. J. M. Peeters, M. Perry, V Pesudo, E. Picciau, M-C Piro, T. R. Pollmann, E. T. Rand, C. Rethmeier, F. Retiere, I Rodriguez-Garcia, L. Roszkowski, J. B. Ruhland, E. Sanchez-Garcia, R. Santorelli, D. Sinclair, P. Skensved, B. Smith, N. J. T. Smith, T. Sonley, J. Soukup, R. Stainforth, C. Stone, V Strickland, M. Stringer, B. Sur, J. Tang, E. Vazquez-Jauregui, S. Viel, J. Walding, M. Waqar, M. Ward, S. Westerdale, J. Willis, A. Zuniga-Reyes
Summary: The DEAP-3600 detector searches for scintillation signal from dark matter particles by using pulse-shape discrimination to suppress the background from 39Ar beta decays. Two PSD estimators and algorithms are used to determine the number of detected photons, with the prompt-fraction performing similarly to the log-likelihood-ratio PSD algorithm if detector effects are not biased. An explanation is provided using a model for the information carried by scintillation photons as a function of the time when they are detected.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Optics
Grace Pakeltis, Enzo Rotunno, Siamak Khorassani, David A. Garfinkel, Robyn Collette, Claire A. West, Scott T. Retterer, Juan Carlos Idrobo, David J. Masiello, Philip D. Rack
Summary: This study leverages the high spatial and energy resolution of monochromated aberration-corrected scanning transmission electron microscopy to investigate the hybridization of cyclic assemblies of plasmonic gold nanorods. The experiments and simulations reveal the coupling of long-axis dipole modes into collective magnetic and electric dipole plasmon resonances, with findings on the energy splitting of the magnetic mode and antibonding modes for oligomers with different polygon edges. Optically, it was found that the extinction efficiencies of electric and magnetic modes are maximized in the n=4 arrangement among the oligomers studied.
Article
Chemistry, Physical
Ryan H. Allaire, Lou Kondic, Linda J. Cummings, Philip D. Rack, Miguel Fuentes-Cabrera
Summary: The study shows that when the phase separation length scale is much smaller than the instability length scale, patterned materials break up into nanoparticles, while soluto-capillarity significantly affects the instability when the two length scales are close. Differences in surface energy between materials can lead to material migration and modify the instability.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Javier A. Diez, Alejandro G. Gonzalez, David A. Garfinkel, Philip D. Rack, Joseph T. McKeown, Lou Kondic
Summary: This study investigates the coupled process of phase separation and dewetting of nanoscale metal alloys on solid substrates through experiments and theoretical modeling. Results indicate the crucial role of temperature dependence of material properties in understanding experimental findings.
Article
Nanoscience & Nanotechnology
David A. Garfinkel, Vasudevan Iyer, Robyn Seils, Grace Pakeltis, Marc R. Bourgeois, Andrew W. Rossi, Clay Klein, Benjamin J. Lawrie, David J. Masiello, Philip D. Rack
Summary: Trimer meta-atoms composed of three gold rods were fabricated and their near-field plasmonic responses were characterized. The magnetic and electric modes of the trimer structure could be tuned by changing the length of the rods. The study also found that the intensity of the electric mode increased more than expected, while the magnetic mode showed the expected tilt dependence. This research opens up new possibilities for studying the nanoscale excited-state of other magnetic meta-atom structures.
ACS APPLIED NANO MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
David A. Garfinkel, Nan Tang, Grace Pakeltis, Reece Emery, Ilia N. Ivanov, Dustin A. Gilbert, Philip D. Rack
Summary: The magnetic and optical properties of AuxCo1-x thin films and nanoparticles can be tuned by controlling their chemical composition and morphology. Annealing leads to phase separation and enhances the magnetic properties. The optical properties are greatly influenced by the chemical morphology, where phase separation enhances the quality factor and optical absorption.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Instruments & Instrumentation
Leo Saturday, Chris Luck, Leslie Wilson, Jason D. Fowlkes, Philip D. Rack, Nicholas J. Evans
Summary: This study presents a method to simulate the Spallation Neutron Source and characterize the thermal failure of NCD foils. A test stand with in situ diagnostics is used to track foil sublimation and thinning, and a COMSOL simulation is developed to assess potential changes to the NCD film and predict foil temperatures under different beam conditions.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2022)
Article
Chemistry, Multidisciplinary
Sumeer R. Khanna, Michael G. Stanford, Ivan V. Vlassiouk, Philip D. Rack
Summary: In this study, CuxN1-x alloy thin films were used as catalysts for graphene growth at atmospheric pressure. By adjusting the alloy composition, the growth of graphene was controlled. The results showed that graphene primarily grew as a single layer when the Cu concentration (x) was above 69 at.%.
Article
Chemistry, Multidisciplinary
Matheus Pianassola, Marlena Alexander, Bryan Chakoumakos, Merry Koschan, Charles Melcher, Mariya Zhuravleva
Summary: The effects of composition on the phase formation of multicomponent garnet crystals grown via directional solidification by the micro-pulling-down method are studied. Crystals with large ionic radii have a central opaque region in optical microscopy images, which is responsible for their reduced transparency. Slow pulling rates can suppress the formation of the opaque region in crystals with intermediate ionic radii.
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE CRYSTAL ENGINEERING AND MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
John Lasseter, Philip D. Rack, Steven J. Randolph
Summary: In this study, a method for selectively depositing 3D nanostructures using photothermal transport is reported. The ability to initiate the process on sub-diffraction-limit nanoscale features is demonstrated. Thermal simulations show that the geometric shape and optical and thermal properties of the nanostructures are crucial for controlling the CVD reaction.
ACS APPLIED NANO MATERIALS
(2022)
Article
Instruments & Instrumentation
Leo Saturday, Leslie Wilson, Philip D. Rack, Nicholas J. Evans
Summary: This study compares the performance of nanocrystalline diamond stripper foils with microcrystalline alternatives under thermal load conditions. An electron beam mimic is used to evaluate their power dissipation and thermal durability, and postmortem testing is conducted to determine their physical properties.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2022)
Article
Chemistry, Multidisciplinary
Jason D. Fowlkes, Robert Winkler, Philip D. Rack, Harald Plank
Summary: This article presents an electron dose compensation strategy, called DBEA, to address the structural artifact issue caused by temperature gradient in 3D nanoprinting using focused electron beam-induced deposition. By modulating the electron dose, the deviations caused by temperature variations can be corrected, thus improving the printing accuracy.
Article
Chemistry, Multidisciplinary
John Lasseter, Philip D. D. Rack, Steven J. J. Randolph
Summary: This study demonstrates the selective growth of high-purity gold films onto nanoscale 3D architectures using the Me2Au (acac) precursor and pulsed laser pyrolytic chemical vapor deposition. The high thermal resistance of the nanoscale geometries enables selective deposition. The effects of laser irradiance, pulse width, and precursor pressure on the growth rate were explored, and feature-targeting resolutions of approximately 100 and 5 μm were achieved using diode lasers coupled to multimode (915 nm) and single mode (785 nm) fiber optics, respectively. Finite element thermal modeling was used to rationalize the experimental results.
Article
Education, Special
Jason D. Fowlkes, Robert Winkler, Philip D. Rack, Harald Plank
Summary: 3D nanoprinting using focused electron beam-induced deposition is susceptible to structural distortions caused by temperature gradients. In this study, an electron dose compensation strategy called the Decelerating Beam Exposure Algorithm (DBEA) is proposed to correct for nanowire bending during computer-aided design. The DBEA utilizes an analytical solution derived from 3D nanoprinting simulations to offset undesired heating effects. This compensation strategy has the potential to improve the fidelity of 3D nanoscale printing.
RESEARCH IN AUTISM SPECTRUM DISORDERS
(2023)
Article
Chemistry, Multidisciplinary
Jason D. Fowlkes, Robert Winkler, Philip D. Rack, Harald Plank
Summary: 3D nanoprinting using focused electron beam-induced deposition often results in structural artifacts caused by temperature gradients during the deposition process. Researchers have developed an electron dose compensation strategy to correct for these artifacts and improve the precision of 3D nanoprinting.
Article
Materials Science, Multidisciplinary
Timothy G. Lach, Chinthaka M. Silva, Yufan Zhou, Walker L. Boldman, Philip D. Rack, William J. Weber, Yanwen Zhang
Summary: This study investigates the behavior of two sets of near-equiatomic CoCrCuFeNi thin films under irradiation in different environments. The results demonstrate the influence of composition and environmental exposure on the stability of high entropy alloys under radiation, providing insights into controlling these behaviors.
NPJ MATERIALS DEGRADATION
(2022)
