XRF (X-ray fluorescence) is a powerful technique for elemental analysis with a high sensitivity. The resolution is presently limited by the size of the primary excitation X-ray beam. A test-bed for confocal-type XRF has been developed to estimate the ultimate lateral resolution which could be reached in chemical mapping using this technique. A polycapillary lens is used to tightly focus the primary X-ray beam of a low power rhodium X-ray source, while the fluorescence signal is collected by a SDD detector through a cylindrical monocapillary. This system was used to characterize the geometry of the fluorescent zone. Capillary radii ranging from 50 μm down to 5 μm were used to investigate the fluorescence signal maximum level This study allows to estimate the ultimate resolution which could be reached in-lab or on a synchrotron beamline. A new tool combining local XRF and scanning probe microscopy is finally proposed.
In this work, the design of an inexpensive and reliable pyranometer used for measuring broadband solar irradiance is proposed. A BPX43 – 4 phototransistor is used as a light detector, which has the spectral response in the range approximately 450 to 1100 nm. This system is controlled by an Arduino pro mini ATmega328P (5 V, 16 MHz) microcontroller and all components are located inside a FB05 black box. Due to a high level of solar radiation in the different environmental conditions, the pyranometer encountered the voltage saturation. Therefore, a 0.25 mm thick of Teflon is selected for attenuating the sunlight. After investigating against a reference sensor, the transmittance of this attenuator is found to be about 12.5%. Finally, the experimental results from the system are compared with a standard pyranometer performed at Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC, 46.80 °N, 9.83 °E and 1, 610 meters above sea level), Switzerland. The results demonstrate a satisfactory agreement between the global irradiance obtained from our proposed pyranometer and the standard pyranometer.
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