Ladislav Musílek

X-ray fluorescence in investigations of cultural relics and archaeological finds

Some characteristic features of X-ray fluorescence (XRF) analysis make it an ideal method for investigations of cultural relics and archaeological finds. It has therefore become a standard method used in archaeometry. Paintings, frescos, manuscripts, pottery, metalwork, glass, and many other objects are analysed with the aim of recognising their materials, production technologies and origin, and for identifying counterfeits. This paper reviews various techniques used in XRF analyses of works of art, summarises the advantages and limitations of the method, and presents some typical examples of its use. The general review is supplemented by some techniques used and some results achieved at CTU-FNSPE in Prague.

Recognition of pigment layers in illuminated manuscripts by means of Kα/Kβ and Lα/Lβ ratios of characteristic X-rays

X-ray fluorescence analysis with an evaluation of the Kalpha/Kbeta or Lalpha/Lbeta count rate ratios enables a layered structure to be recognized, because the measured ratio of two lines of one element depends on the depth distribution of this element in the analyzed objects. Several specimens consisting of layers of various pigments were analyzed to demonstrate the possibilities of the proposed technique. Then the Lalpha/Lbeta technique was applied in an investigation of cinnabar distribution in mediaeval manuscripts.

X-ray fluorescence analyzers for investigating postmediaeval pottery from Southern Moravia.

This paper deals with an investigation of ceramic archaeological finds with the use of in-situ X-ray fluorescence analysis. Firstly, three configurations of X-ray fluorescence analyzers constructed and used at the Czech Technical University in Prague are described and compared for use in a non-destructive survey of siliceous materials. Detection limits, depth of analysis, the relation of the analyzed area, the homogeneity of the samples, and variations in the element concentrations are discussed. Secondly, many shards of postmediaeval pottery from Southern Moravia are analyzed with X-ray fluorescence analysis and some of them also with electron microprobe analysis. Selected results are described.

Application of X-ray fluorescence in investigations of Bohemian historical manuscripts.

In this work we present the application of X-ray fluorescence analysis (XRFA) in an investigation of the Land Register and the Register of the Court of the Kingdom of Bohemia and the manuscript of the Homiliary of the Opatovice Monastery from the 12th century. Radionuclide sources emitting radiation at an appropriate energy level and an X-ray tube were used to excite the characteristic radiation. A spectrometric Si(Li) detector and a Si-PIN detector with Peltier cooling were used to detect the excited characteristic radiation. Several types of pigments were identified and compositions of inks used within almost 5 centuries in the offices at the Prague Castle were determined.

Analysis of fresco paintings by X-ray fluorescence method

Abstract An XRF technique was used for the analysis of fresco paintings. The analysis of paintings makes it possible to examine pigmented materials. An application of the method is used to illustrate the technique.

X-ray fluorescence in research on Czech cultural monuments

Abstract 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.

The laboratory of quantitative methods in historic monument research at the CTU Prague

Abstract A “Laboratory of Quantitative Methods in Historic Monument Research” has been established at the Department of Dosimetry and Application of Ionizing Radiation of the CTU Prague. Its primary orientation is the investigation of historic architecture, although other objects of art can also be investigated. In the first phase, one investigative method was established for each of the above groups: X-ray fluorescence as the analytic method, thermoluminescence for dating and photogrammetry for surveying. The first results demonstrate the need and usefulness of these methods for investigations in the rich architectural heritage of the Czech Republic.

The use of the Monte Carlo method for the calculation of build-up factors in wide conical gamma-radiation beams

Abstract The values of the build-up factors for the number of photons are presented in this paper. The results were obtained for the number of photons in wide conical gamma-ray beams penetrating through various material slabs. The dependence of the build-up factor on the thickness of the material slabs were computed by the Monte Carlo method.

Empirical formulae for build-up factor calculations in wide conical γ-ray beams

Abstract The work deals with build up factors for the number of photons and for the exposure in wide conical γ-ray beams penetrating through iron slabs. The formulae for calculation of build up factor values and comparison of computed results with the experimental ones are presented.

Analysis of Potassium in Bricks—Determining the Dose Rate from 40K for Thermoluminescence Dating

Thermoluminescence (TL) dating is based on accumulating the natural radiation dose in the material of a dated artefact (brick, pottery, etc.), and comparing the dose accumulated during the lifetime of the object with the dose rate within the sample collected for TL measurement. Determining the dose rate from natural radionuclides in materials is one of the most important and most difficult parts of the technique. The most important radionuclides present are usually nuclides of the uranium and thorium decay series and 40K. An analysis of the total potassium concentration enables us to determine the 40K content effectively, and from this it is possible to calculate the dose rate originating from this radiation source. X‐ray fluorescence (XRF) analysis can be used to determine the potassium concentration in bricks rapidly and efficiently. The procedure for analysing potassium, examples of results of dose rate calculation and possible sources of error are described here.