The magnetic field effect of K X-ray fluorescence parameters of elements in the range 39 ≤ Z ≤ 48

In this work, the fluorescence parameters (the fluorescence cross section (σ), the fluorescence yield (ω), and vacancy transfer probability (η)) of the fifth period elements, which have great potential to be developed as a technology, are investigated by taking advantage of interactions between atoms and radiation. For this process, the samples were excited via 241Am source without magnetic field and in the external magnetic field. The radiation emitted from targets was collected by an Si(Li) detector and energy channels were located on a computer program by means of a multi-channel analyzer. The data on the computer program were analyzed for calculations. The discrepancies have been observed between the experimental results and the theoretical results calculated without magnetic field. It was determined that results changed with the magnetic field (B = 0.4 and 0.8 T) and the variation of the X-ray fluorescence (XRF) parameters with the magnetic field for diamagnetic Ag and Cd is lower than for paramagnetic elements.

Remote Detection of the Fluorescence Spectrum of Natural Pollens Floating in the Atmosphere Using a Laser-Induced-Fluorescence Spectrum (LIFS) Lidar

A mobile laser-induced fluorescence spectrum (LIFS) lidar was developed for monitoring pollens floating in the atmosphere. The fluorescence spectrum of pollens excited at 355 nm was measured with a fluorescence spectrometer and the results suggested that in general they had peaks at around 460 nm and the ranges were 400–600 nm. A fluorescence spectrum database of 25 different pollens was made with the 355 nm excitation. Based on these results, we developed a LIFS lidar that had features in pollen species identification and daytime operation. The former was achieved by the database and the latter was possible by introducing a synchronous-delay detection to a gated CCD spectrometer in an operation time of 200 ns. Fluorescence detection of pollens floating in the atmosphere was performed using the LIFS lidar in a field where cedars grow in the spring and ragweed in the autumn. The LIFS lidar system successfully detected fluorescence spectrums of the pollens at a distance of approximately 20 m away. We discussed the performance of the LIFS lidar by estimating the number of cedar pollens using a lidar equation, introducing a fluorescence cross section of cedar pollens and a sensitivity of the CCD spectrometer that was measured by ourselves.

Synthesis and photophysical properties of doubly porphyrin-substituted cyanine dye

New porphyrin-(cyanine dye) composites, in which two porphyrins are bridged by a cyanine dye through triple bonds, were synthesized. In the UV-vis absorption spectra of the composites, the Soret band and Q-band were red-shifted to 436 and 575–640 nm, respectively. The absorption originating from the cyanine dye portion was also red-shifted from 710 nm to 764 nm, suggesting the expansion of πconjugation over the porphyrin and cyanine dye parts. Fluorescence studies suggested that energy transfer from the porphyrin portion to the cyanine dye moiety occurred. The fluorescence intensity decreased with increasing dielectric constants of solvents, suggesting intramolecular photoinduced electron transfer from the porphyrin to the cyanine dye parts. The effective two-photon absorption (2PA) cross-section values were measured using a nanosecond open aperture Z-scan method. The maximum effective 2PA cross-section and two-photon excited fluorescence cross-section values were 33,000 GM and 4,800 GM, respectively, at 860 nm in toluene/pyridine (95:5).

Angular variations of K and L X-ray fluorescence cross sections for some lanthanides

Kα, Kβ, Lα, and Lβ X-ray fluorescence cross sections for lanthanides in the atomic range 62 ≤ Z ≤ 68 (Sm, Eu, Gd Tb, Dy, Ho, and Er) were simultaneously measured by 59.54 keV incident photon energy at five angles ranging from 120° to 160°. The measurements were performed using an Am-241 radioisotope as the photon source and a Si(Li) detector. The Lα X-ray fluorescence cross section (σLα) was found to decrease with increasing emission angle and showed an anisotropic distribution of Lα X-rays. Kα, Kβ, and Lβ X-ray fluorescence cross sections (σKα, σKβ, and σLβ) were observed to be angle-independent and showed an isotropic distribution of Kα, Kβ, and Lβ X-rays. The Kα and Kβ X-rays originate from filling of the K shell (J = 1/2) vacancies, Lβ X-rays from filling of the L1 and L2 (J = 1/2) subshell vacancies, and Lα X-rays from filling of the L3 subshell (J = 3/2) vacancy. The fluorescent X-rays originating from the vacancy states with J = 1/2 are isotropic and unpolarized, but fluorescent X-rays originating from the vacancy states with J > 1/2 are anisotropic and polarized. Thus, the atomic inner shells vacancy states with J > 1/2 are aligned whereas vacancy states with J = 1/2 are not aligned. Lα fluorescence X-rays have an anisotropic distribution, while Kα, Kβ, and Lβ fluorescence X-rays have isotropic distribution. Furthermore, the IKβ/IKα, ILα/IKα}, ILβ/IKα, and ILβ/ILα intensity ratios for the elements under investigation were determined. The experimental cross sections and intensity ratios for Kα, Kβ, Lα, and Lβ fluorescence X-rays were also determined, and these experimental values were compared with our calculated theoretical values.PACS Nos.: 32.30.Rj, 32.80.Cy