Even though conventional X-ray polarizers with multiple-reflection channel-cut structures perform well, they suffer from the disadvantage that the polarized beam is non-stationary as the energy is scanned. In this paper the possibility of using a thin Bragg reflector as a polarizing filter is investigated, so that the transmitted beam (rather than the Bragg-reflected beam) is used. Consequently, the position and direction of the transmitted beam are unchanged as the energy is changed, or even when the polarization direction to be filtered out is changed. Theoretical considerations as well as experimental results on the performance characteristics of the proposed transmission-type X-ray linear polarizer are presented. A polarization ratio, defined as I(H)/I(V), higher than 10(5) was obtained.
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http://dx.doi.org/10.1107/S0909049597019560 | DOI Listing |
Biomed Phys Eng Express
September 2024
Department of Medical Imaging and Radiological Sciences, Tzu-Chi University, Hualien, Taiwan.
Med Phys
December 2023
Medical Physics and Radiation Measurements Laboratory, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC.
Purpose: Transmission-target x-ray tubes generate more x-rays than reflection thick-target x-ray tubes. A transmission x-ray tube combined with radiosensitizers has a better radiation enhancement effect. This study investigated the feasibility of using a transmission x-ray tube with radiosensitizers in clinical radiotherapy and its effect on radiation dose enhancement.
View Article and Find Full Text PDFRev Sci Instrum
November 2022
Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
The Imaging Spectroscopy Snout (ISS) used at the National Ignition Facility is able to simultaneously collect neutron pinhole images, 1D spatially resolved x-ray spectra, and time resolved x-ray pinhole images. To measure the x-ray spectra, the ISS can be equipped with up to four different transmission crystals, each offering different energy ranges from ∼7.5 to ∼12 keV and different resolutions.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2023
School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China.
Near-infrared organic photodetectors (NIR-OPDs) are significant technologies in emerging biomedicine applications for uniquely wearable, noninvasive, low-cost advantages. However, biosignals are weak and changing rapidly so practical biodetection and bioimaging are still challenging for NIR-OPDs. Herein, high-performance NIR-OPDs with synchronous optical output are realized by recombining anode-injected electrons with photogenerated holes on emitters.
View Article and Find Full Text PDFMaintaining a high spatial resolution in photoacoustic microscopy (PAM) of deep tissues is difficult due to large aberration in an objective lens with high numerical aperture and photoacoustic wave attenuation. To address the issue, we integrate transmission-type adaptive optics (AO) in high-resolution PAM with a low-frequency ultrasound transducer (UT), which increases the photoacoustic wave detection efficiency. AO improves lateral resolution and depth discrimination in PAM, even for low-frequency ultrasound waves by focusing a beam spot in deep tissues.
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