X-ray fluorescence analysis (XRF) is a widespread and preferred method for a variety of analytical applications. Among other things, due to its non-invasiveness and non-destructiveness, it is an ...excellent method for exploring the valuable objects of our cultural heritage. At the same time, however, the fact that it uses relatively low energy X-rays brings some limitations and problems in interpreting the measurement results, especially if objects with inhomogeneous structure are investigated. The depth in the examined material from which characteristic X-rays are detected is in the order of tens to hundreds of μm, depending on the measured element and composition and density of the material. During the development and use of XRF, several procedures have been developed to estimate whether the examined element is distributed homogeneously in the measured layer or has a depth uneven distribution. The least difficult is the measurement under different angles of excitation and excited radiation impact and emission. More sophisticated options are the simultaneous use of Kα and Kβ lines, or K and L lines. The most comprehensive information can be obtained in the confocal arrangement of the spectrometer, where both incident and emitted radiation are narrowly collimated, and the intersection of the two collimated beams is gradually moved under the surface of the object under investigation. The aim of this review paper is to summarize possible procedures for identifying the inhomogeneous structure of the material and test them in the model case of the thickness standards for the copper layer on the steel.
•The possibilities of XRF analysis of materials with inhomogeneous structure are investigated.•The work compares different methods of identifying inhomogeneities in the depth structure of objects.•The methods are tested on the copper coating standards on the steel substrate.•The results demonstrate the good usability of the methods, but only to depths of several tens of micrometre.
A brief review of application of X-ray fluorescence analysis (XRFA) to fine and applied arts related to Czech cultural heritage is presented. The Department of Dosimetry and Application of Ionising ...Radiation of CTU-FNSPE has used XRFA in collaboration with various Czech institutions dealing with cultural history for many kinds of artefacts, (e.g., Roman and medieval brass, gemstones and noble metals from the sceptre of one of the faculties of the Charles University in Prague, millefiori beads, etc.). In some cases, a combination of various other techniques alongside XRFA was used for enhancing our knowledge of a measured object.
•X-ray fluorescence analysis is a versatile tool for investigations into cultural heritage.•Applications of XRFA in the field of fine and applied arts are briefly reviewed.•The applications are based on investigations of Czech cultural heritage.•Improvements to instrumentation and techniques are mentioned.•Selected results of the investigations are commented in the historical context.
X-ray tubes belong among the most important sources of ionizing radiation and are used in various applications and methods, i.e. investigation of materials, diagnostics in medicine, irradiation, etc. ...For such applications, the exact properties of X-ray sources or their X-ray beams need to be known, as well as when Monte Carlo simulations of experimental setups are considered with the aim of optimization or calibration of X-ray systems. These properties include X-ray spectra, beam profiles, divergence and homogeneity of beams. Properties of low power X-ray tubes with the maximum voltage up to 50 kV were investigated in this study. These devices included a small laboratory X-ray tube with collimated X-ray beam and a microfocus X-ray tube with polycapillary focusing optics. Beam shape features were reconstructed using a silicon pixel detector. The pixel detector was inserted into X-ray beams at different distances from X-ray sources. Beam 2D profiles were obtained and since the pixel detector worked in a single event detection mode, approximate energy of individual photons could be measured as well as their position. In this way, detailed information about the beam properties was obtained.
•X-ray beam parameters are mapped by a pixel detector.•The beam shape and energy distribution of the emitted photons are assessed.•The size of the irradiated point and the quality of the collimators are determined.
Knowledge of the content of natural radionuclides in bricks can be important in some cases in dosimetry and application of ionizing radiation. Dosimetry of naturally occurring radionuclides in matter ...(NORM) in general is one of them, the other one, related to radiation protection, is radon exposure evaluation, and finally, it is needed for the thermoluminescence (TL) dating method. The internal dose rate inside bricks is caused mostly by contributions of the natural radionuclides 238U, 232Th, radionuclides of their decay chains, and 40K. The decay chain of 235U is usually much less important.
The concentrations of 238U, 232Th and 40K were measured by various methods, namely by gamma-ray spectrometry, X-ray fluorescence analysis (XRF), and neutron activation analysis (NAA) which was used as a reference method. These methods were compared from the point of view of accuracy, limit of detection (LOD), amount of sample needed and sample handling, time demands, and instrument availability.
•Contents of naturally occurring radionuclides U, Th and K in bricks were determined.•Homogeneity was tested by neutron activation analysis and X-ray fluorescence analysis.•Distribution of particle size was evaluated after two types of grinding.•X-ray fluorescence appeared to be the least suitable for the determination.•Gamma-ray spectrometry can give results comparable to neutron activation analysis.
X-ray florescence analysis is an excellent non-destructive tool for analysing the elemental composition of materials in a wide range of works of art. The Department of Dosimetry and Application of ...Ionising Radiation at CTU-FNSPE has used radionuclide or X-ray tube excited energy dispersive X-ray fluorescence for many kinds of artefacts, including frescos, paintings, manuscripts, metal sculptures and other objects, ceramics, jewellery, various archaeological finds, etc. The method used is more or less “traditional”, i.e., semiconductor spectrometry of excited X-rays, with some optional choices—capillary optics for collimation of exciting beams and two-dimensional scanning. The “hardware” complex is supplemented by techniques for estimating the depth distribution of measured elements, for suppressing surface effects, for in situ non-contact measurements, etc. Extending the measurable range to lighter elements and decreasing the detection limits is one of the achievements that has been attained by improving the instrumentation and techniques that are used. This paper gives a brief review of works carried out at the Department of Dosimetry and Application of Ionising Radiation at CTU-FNSPE.
► X-ray fluorescence analysis as a non-destructive tool for investigating various artefacts. ► Improving instrumentation and experimental techniques for analysis. ► Extending the measurable range to lighter elements and decreasing the detection limits.
This paper deals with difficulties in making a quantitative evaluation with the use of in-situ X-ray fluorescence analysis. Incorrect sample positioning and some properties of the surface of the ...sample have a negative effect on quantitative analyses. Monte Carlo simulations with the MCNPX code were used for classifying the disturbing effects that must be taken into account in-situ X-ray fluorescence analysis. The relation between the count rate and variations in the geometrical arrangement has been studied. The Monte Carlo calculations provide an interpretation of effects that had been ascertained experimentally and also imply the range of uncertainties in the count rates. The results enable us to find an optimal set-up for a given in-situ measurement.
X-ray fluorescence as a tool for investigating archaeological finds Čechák, T.; Hložek, M.; Musílek, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2007, Letnik:
580, Številka:
1
Journal Article
Recenzirano
X-ray fluorescence analysis (XRFA) is an outstanding method for investigations of various objects of historic and cultural significance, as it is non-destructive, can be used without any sampling of ...the analysed artefacts and, if necessary, measurements can be carried out in situ. The laboratory at CTU FNSPE is equipped for XRFA with radionuclides
55Fe,
238Pu and
241Am and with a small X-ray tube (30
kV) as excitation sources, and with Si(Li) and Si-PIN semiconductor spectrometers for detecting XRF spectra. This paper deals with XRFA of archaeological finds. Practical examples are selected from investigations of ceramic objects from excavations in the Czech Republic.
X-ray fluorescence in investigations of archaeological finds Čechák, T.; Hložek, M.; Musílek, L. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
10/2007, Letnik:
263, Številka:
1
Journal Article
Recenzirano
X-ray fluorescence can be successfully used for analysing the elemental composition of the superficial layers of a measured object, especially for investigating surface coatings, deposits of ...adventitious materials on the surface, etc. An energy dispersive version of X-ray fluorescence analysis is used in our investigations for analysing various historic objects, art works and archaeological finds. Examples of the application of X-ray fluorescence to various archaeological finds from excavations in the Czech Republic are presented – shards of ancient glazed ceramics, moulds for casting metal products, the remains of a human finger with traces of brass, probably from a ring, etc.
The paper describes the use of oak tree (
Quercus robur,
Quercus petraea) bark for determining the distribution of air pollution by heavy metals and other elements in the western part of the Czech ...Republic, known as Bohemia. The samples collected were analysed by instrumental neutron activation analysis (INAA) in IRI TU Delft. To obtain sulphur concentration radionuclide X-ray fluorescence analysis (RXRFA) was applied in CTU-FNSPE. Out of all the determined elements 24 (Al, As, Ce, Co, Cr, Cs, Fe, Hf, Hg, La, Mn, Na, Ni, Rb, S, Sb, Sc, Se, Th, Ti, U, V, W, Zn) were selected as the most important. Then the data were analysed by Monte Carlo-assisted factor analysis (MCAFA) with the aim of resolving and identifying the environmental pollution sources. Some of the factors were interpreted as fly ash, coal combustion, Zn industry, waste incinerator plant, crustal material or metal industry. The geographical distribution patterns of the factors are also available.
X-ray fluorescence in research on Czech cultural monuments Čechák, T.; Gerndt, J.; Kopecká, I. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
2004, 2004-01-00, Letnik:
213
Journal Article
Recenzirano
Radionuclide X-ray fluorescence analysis (RXRFA), as a non-destructive method, relatively simple and allowing measurements to be carried out in situ, is an excellent tool in research on various ...objects of art. A range of artefacts have been investigated by our laboratory, in part for the purposes of history of art and in part as a basis for restoration works – medieval frescoes in some Czech castles and churches, metal sculptures and objects of applied art, paints and inks of old manuscripts, paintings. Some of these are among the most valuable monuments in the Czech cultural heritage. The contribution of the results of the tests to the investigation of their “life story” and, in some cases, to their conservation, is not negligible. Later additions and repairs can be recognised, and materials and technologies that are close to their historic counterparts can be used in restoration work.
