Two VUV-grade BaF2 windows with 0.5 mm-thick and 1 mm-thick respectively were selected to study the transmittance variety with the temperature. The results show that the cutoff wavelength of BaF2 crystals will shift towards the long wave with the increase in temperature. In a certain temperature range, BaF2 crystals can depress 130.4 nm radiation well, and also has a high transmittance at 135.6 nm. Compared with the reported method in which SrF2 crystals can be applied to suppress 130.4 nm stray light by heating, BaF2 crystal can inhibit the 130. 4 nm emission line completely, and thus reduce the power consumption of the device at the same time. This indicates that BaF2 crystals can play an important role in the ionosphere optical remote sensing detection.
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Phys Med Biol
November 2024
Department of Radiology, Stanford University, Stanford, CA, United States of America.
Achieving ultra-precise temporal resolution in ionizing radiation detection is essential, particularly in positron emission tomography, where precise timing enhances signal-to-noise ratios and may enable reconstruction-less imaging. A promising approach involves utilizing ultrafast modulation of the complex refractive index, where sending probe pulses to the detection crystals will result in changes in picoseconds (ps), and thus a sub-10 ps coincidence time resolution can be realized. Towards this goal, here, we aim to first measure the ps changes in probe pulses using an ionizing radiation source with high time resolutionWe used relativistic, ultrafast electrons to induce complex refractive index and use probe pulses in the near-infrared (800 nm) and terahertz (THz, 300m) regimes to test the hypothesized wavelength-squared increase in absorption coefficient in the Drude free-carrier absorption model.
View Article and Find Full Text PDFWe report on the first, to our knowledge, room-temperature continuous-wave laser operation of Tm,Ho-codoped barium and strontium fluoride crystals at ∼2.1 µm. The 3 at.
View Article and Find Full Text PDFACS Omega
September 2024
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States.
Fluoride-ion batteries have several potential advantages over lithium-ion batteries. Materials development is still needed, however, to realize electrolytes with sufficiently high anion conductivity and compatibility with anode and cathode layers. Fluoride compounds are difficult to synthesize directly as single crystals but can be realized from oxide film precursors via topotactic chemistry techniques.
View Article and Find Full Text PDFEJNMMI Phys
July 2024
Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany.
Background: Good timing resolution in medical imaging applications such as TOF-CT or TOF-PET can boost image quality or patient comfort significantly by reducing the influence of background noise. However, the timing resolution of state-of-the-art detectors in CT and PET are limited by their light emission process. Core-valence cross-luminescence is an alternative, but well-known compounds (e.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2024
Faculty of Mechanical and Electrical Engineering, Kunnming University of Science and Technology, 650500 Kunming, China.
Monocrystalline barium fluoride (BaF), known for its exceptional optical properties in the infrared spectrum, exhibits anisotropy that influences surface quality and material removal efficiency during ultraprecision machining. This research explores the impact of anisotropy on the deformation and removal mechanisms of monocrystalline BaF by integrating nanoscratch tests with molecular dynamics (MD) simulations. Nanoscratch tests conducted on variously oriented monocrystalline BaF surfaces using a ramp loading mode facilitated the identification of surface cracks and a systematic description of material removal behaviors.
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