Confocal micro-beam X-ray fluorescence analysis (confocal micro-XRF) is a non-destructive analytical tool for investigation of sample composition that enables acquiring three-dimensionally resolved information. This work describes a calibration procedure of a laboratory confocal micro-XRF setup, which leads to determination of its characteristic parameters. The calibration is performed using a tabletop confocal micro-XRF spectrometer designed recently at the Czech Technical University in Prague. The calibration procedure performed within this work comprises the essential steps of the setup characterization: excitation spectrum calculation, experimental determination of energy-dependent confocal volume size and integral sensitivity and calculation of the spectrometer sensitivity function. The results of the setup calibration will be used for development of a procedure enabling quantitative evaluation of the measured depth profiles.

• MeSH
• algoritmy MeSH
• fluorescence * MeSH
• kalibrace MeSH
• lidé MeSH
• rentgenové záření MeSH
• spektrometrie rentgenová emisní přístrojové vybavení   metody   normy   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

Investigations by micrometer-scale X-ray fluorescence and X-ray absorption fine structure (micro-XRF and micro-XAFS) recorded in a confocal geometry on a bore core section of a uranium-rich tertiary sediment are performed in order to assess mechanisms leading to immobilization of the uranium during diagenesis. Results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(O); we found no evidence for As(III). The As(O) is observed to be intimately associated with the surface of Fe(II) nodules and likely arsenopyrite. A hypothesis for the mechanism of uranium immobilization is proposed, where arsenopyrite acted as reductant of groundwater-dissolved U(VI), leading to precipitation of less soluble U(IV) and thereby forming As(V).

• MeSH
• absorpční fotometrie metody   MeSH
• arsenikové přípravky analýza   chemie   MeSH
• chemické modely * MeSH
• geologické sedimenty analýza   MeSH
• radioaktivní látky znečišťující půdu analýza   MeSH
• radioaktivní odpad analýza   MeSH
• sloučeniny uranu analýza   chemie   MeSH
• spektrometrie rentgenová emisní metody   MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH