Polarized XRF Spectrometer with a 40-mW X-Ray Tube

A three-dimensional polarized X-ray fluorescence (XRF) spectrometer was assembled with a low-power X-ray tube of 40 milliwatts, and a sample of stainless steel was measured with an acrylic polarizer. Based on the Schr?dinger’s wave picture of Compton scattering, the dependence of the de Broglie wavelength and the scattering angle of a recoil electron on the incident X-ray energy were calculated. When the incident X-rays were scattered at an angle of 90°, the de Broglie of the recoil electron always went away at an angle of 45° with the incident X-rays and the de Broglie wavelength varied for any wavelength of the incident X-rays, i.e. we could select the scattering angle of the recoil electron to be 45°according to the incident X-ray energy and it could then be regarded as 45° Bragg diffraction that could produce highly polarized X-rays. The polarization measurement of scattered X-rays from an acrylic and lead plates substantiated that Compton scattered X-rays from the acrylic plate had higher degree of polarization than the elastically scattered X-rays from the lead plate. Highly polarized Compton scattered X-rays from the light-element polarizer led to the background reduction and the changes of the characteristic X-ray intensity in XRF spectra measured by our laboratory-made spectrometer.Трехмерный рентгеновский флуоресцентный спектрометр с поляризатором (РФА) был собран с использованием маломощной рентгеновской трубки. Размер спектрометра составлял 25 см в длину, ширина и высота по 10 см. Расстояние от рентгеновской трубки до поляризатора составляло 10 мм, между образцом и детектором ? 10 мм. Камера образцов не вакуумировалась. Образец устанавливали на дно акрилового блока. Рентгеновское излучение падало на поляризатор под углом 45? , и после отражения направлялось на образец под углом в 45? . Использовали рентгеновскую трубку с вольфрамовым анодом фирмы Moxtek (номинальная мощность 4 Вт, максимальное напряжение 50 кВ). В качестве поляризатора использовали акриловую (C5H2 O8 )n пластину площадью 80 мм2 и толщиной 30 мм. Излучение регистрировали детектором SDD (RES-Lab, Osaka) площадью 100 мм2 , толщина кремниевого кристалла составляла 450 мкм. Толщина бериллиевого окна ? 8 мкм. Холодильник Пельтье понижал температуру детектора до -30 ° С. Образец из нержавеющей стали измеряли c акриловым поляризатором. На основе волновой теории Шредингера комптоновского рассеяния рассчитана зависимость длины волны де Бройля и угла рассеяния электрона отдачи в зависимости от энергии падающего рентгеновского излучения. Измерение поляризации рассеянного рентгеновского излучения подтвердило, что некогерентно рассеянное на акриловой пластинке рентгеновское излучение имело более высокую степень поляризации, чем когерентно рассеянное рентгеновское излучение от свинцовой пластины. Высокополяризованное некогерентно рассеянное рентгеновское излучение от поляризатора из элемента с малым атомным номером привело к уменьшению фона и изменению интенсивности характеристического рентгеновского излучения в РФА спектрах, измеренных нашим лабораторным спектрометром

POLARIZED XRF SPECTROMETER WITH A 40-mW X-RAY TUBE

A three-dimensional polarized X-ray fluorescence (XRF) spectrometer was assembled with a low-power X-ray tube of 40 milliwatts, and a sample of stainless steel was measured with an acrylic polarizer. Based on the Schrödinger’s wave picture of Compton scattering, the dependence of the de Broglie wavelength and the scattering angle of a recoil electron on the incident X-ray energy were calculated. When the incident X-rays were scattered at an angle of 90°, the de Broglie of the recoil electron always went away at an angle of 45° with the incident X-rays and the de Broglie wavelength varied for any wavelength of the incident X-rays, i.e. we could select the scattering angle of the recoil electron to be 45°according to the incident X-ray energy and it could then be regarded as 45° Bragg diffraction that could produce highly polarized X-rays. The polarization measurement of scattered X-rays from an acrylic and lead plates substantiated that Compton scattered X-rays from the acrylic plate had higher degree of polarization than the elastically scattered X-rays from the lead plate. Highly polarized Compton scattered X-rays from the light-element polarizer led to the background reduction and the changes of the characteristic X-ray intensity in XRF spectra measured by our laboratory-made spectrometer.Key words: polarized X-ray fluorescence  spectrometer, stainless steel, acrylic polarizer, Compton scattering, background.DOI: http://dx.doi.org/10.15826/analitika.2018.22.2.010A three-dimensional polarized X-ray fluorescence (XRF) spectrometer was assembled with a low-power X-ray tube of 40 milliwatts, and a sample of stainless steel was measured with an acrylic polarizer. Based on the Schrödinger’s wave picture of Compton scattering, the dependence of the de Broglie wavelength and the scattering angle of a recoil electron on the incident X-ray energy were calculated. When the incident X-rays were scattered at an angle of 90°, the de Broglie of the recoil electron always went away at an angle of 45° with the incident X-rays and the de Broglie wavelength varied for any wavelength of the incident X-rays, i.e. we could select the scattering angle of the recoil electron to be 45°according to the incident X-ray energy and it could then be regarded as 45° Bragg diffraction that could produce highly polarized X-rays. The polarization measurement of scattered X-rays from an acrylic and lead plates substantiated that Compton scattered X-rays from the acrylic plate had higher degree of polarization than the elastically scattered X-rays from the lead plate. Highly polarized Compton scattered X-rays from the light-element polarizer led to the background reduction and the changes of the characteristic X-ray intensity in XRF spectra measured by our laboratory-made spectrometer.Key words: polarized X-ray fluorescence  spectrometer, stainless steel, acrylic polarizer, Compton scattering, background.DOI: http://dx.doi.org/10.15826/analitika.2018.22.2.01

High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p–n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM. We also demonstrated that the same device operates as a high-speed and high-efficiency Ge photodetector with the Franz-Keldysh (F-K) and avalanche-multiplication effects. These results demonstrate that the Ge/Si stacked structure is promising for both high-performance optical modulators and photodetectors integrated on Si platforms

Real-world management of treatment-naïve diabetic macular oedema : 2-year visual outcome focusing on the starting year of intervention from STREAT-DMO study

Background/aims To investigate the yearly change of real-world outcomes for best corrected visual acuity (BCVA) after 2-year clinical intervention for treatment-naïve diabetic macular oedema (DMO). Methods Retrospective analysis of aggregated, longitudinal medical records obtained from 27 retina specialised institutions in Japan from Survey of Treatment for DMO database. A total of 2049 treatment-naïve centre involving DMO eyes of which the initial intervention started between 2010 and 2015, and had been followed for 2 years, were eligible. As interventions, antivascular endothelial growth factor (VEGF) agents, local corticosteroids, macular photocoagulation and vitrectomy were defined. In each eye, baseline and final BCVA, the number of each intervention for 2 years was extracted. Each eye was classified by starting year of interventional treatment. Results Although baseline BCVA did not change by year, 2-year improvement of BCVA had been increased, and reached to +6.5 letters in the latest term. There is little difference among starting year about proportions of eyes which BCVA gained >15 letters, in contrast to those which lost >15 letters were decreased by year. The proportion of eyes receiving anti-VEGF therapy was dramatically increased, while those receiving the other therapies were gradually decreased. The proportion of eyes which maintained socially good vision of BCVA>20/40 has been increased and reached to 59.0% in the latest term. Conclusion For recent years, treatment patterns for DMO have been gradually but certainly changed; as a result, better visual gain, suppression of worsened eyes and better final BCVA have been obtained. Anti-VEGF therapy has become the first-line therapy and its injection frequency has been increasing

Real-world management of treatment-naïve diabetic macular oedema in Japan : two-year visual outcomes with and without anti-VEGF therapy in the STREAT-DME study

Background/Aims To investigate real-world outcomes for best-corrected visual acuity (BCVA) after 2-year clinical intervention for treatment-naïve, centr-involving diabetic macular oedema (DME). Methods Retrospective analysis of longitudinal medical records obtained from 27 institutions specialising in retinal diseases in Japan. A total of 2049 eyes with treatment-naïve DME commencing intervention between 2010 and 2015 who were followed for 2 years were eligible. Interventions for DME included anti-vascular endothelial growth factor (VEGF) therapy, local corticosteroid therapy, macular photocoagulation and vitrectomy. Baseline and final BCVA (logMAR) were assessed. Eyes were classified by the treatment pattern, depending on whether anti-VEGF therapy was used, into an anti-VEGF monotherapy group (group A), a combination therapy group (group B) and a group without anti-VEGF therapy (group C). Results The mean 2-year improvement of BCVA was −0.04±0.40 and final BCVA of >20/40 was obtained in 46.3% of eyes. Based on the treatment pattern, there were 427 eyes (20.9%) in group A, 807 eyes (39.4%) in group B and 815 eyes (39.8%) in group C. Mean improvement of BCVA was −0.09±0.39, –0.02±0.40 and −0.05±0.39, and the percentage of eyes with final BCVA of >20/40 was 49.4%, 38.9%, and 52.0%, respectively. Conclusion Following 2-year real-world management of treatment-naïve DME in Japan, BCVA improved by 2 letters. Eyes treated by anti-VEGF monotherapy showed a better visual prognosis than eyes receiving combination therapy. Despite treatment for DME being selected by specialists in consideration of medical and social factors, a satisfactory visual prognosis was not obtained, but final BCVA remained >20/40 in half of all eyes

Multimode interference coupler for mode division multiplexed systems

Multimode interference (MMI) coupler for multimode system is proposed based on Si waveguide platform. Each mode is separated and injected into the mNxmN MMI coupler with m being the number of modes and N is the multiplication number of input image. </p

Enhancement of Glutamine Utilization in Bacillus subtilis through the GlnK-GlnL Two-Component Regulatory System

During DNA microarray analysis, we discovered that the GlnK-GlnL (formerly YcbA-YcbB) two-component system positively regulates the expression of the glsA-glnT (formerly ybgJ-ybgH) operon in response to glutamine in the culture medium on Northern analysis. As a result of gel retardation and DNase I footprinting analyses, we found that the GlnL protein interacts with a region (bases −13 to −56; +1 is the transcription initiation base determined on primer extension analysis of glsA-glnT) in which a direct repeat, TTTTGTN4TTTTGT, is present. Furthermore, the glsA and glnT genes were biochemically verified to encode glutaminase and glutamine transporter, respectively