D. Banaś

An elemental correlation study in cancerous breast tissue by total reflection x-ray fluorescence

The total reflection x-ray fluorescence method (TRXRF) has been employed to determine of P, S, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Rb, Sr, and Pb concentration in the benign breast tumor tissue from 68 women and in the cancerous breast tissue from 26 women. Concentrations of most of elements show enhancement in cancerous breast tissue. Examined elements compete for binding sites in the cell, change its enzymatic activity, and exert direct or indirect action on the carcinogenic process accelerating the growth of rumors. Inhibition of enzymatic activity caused by variation in trace element concentrations results in immunological breakdown of the body system. An attempt has been made to correlate measured trace element concentrations with the clinical stage of cancer. Physical bases of used analytical method, experimental setup, and the procedure of sample preparation are described.

Trace element load in cancer and normal lung tissue

Abstract Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described.

Some aspects of statistical distribution of trace element concentrations in biomedical samples

Concentrations of trace elements in biomedical samples were studied using X-ray fluorescence (XRF), total reflection X-ray fluorescence (TRXRF) and particle-induced X-ray emission (PIXE) methods. Used analytical methods were compared in terms of their detection limits and applicability for studying the trace elements in large populations of biomedical samples. In a result, the XRF and TRXRF methods were selected to be used for the trace element concentration measurements in the urine and woman full-term placenta samples. The measured trace element concentration distributions were found to be strongly asymmetric and described by the logarithmic–normal distribution. Such a distribution is expected for the random sequential process, which realistically models a level of trace elements in studied biomedical samples. The importance and consequences of this finding are discussed, especially in the context of comparison of the concentration measurements in different populations of biomedical samples.

Application of the high-resolution grazing-emission x-ray fluorescence method for impurities control in semiconductor nanotechnology

We report on the application of synchrotron radiation based high-resolution grazing-emission x-ray fluorescence (GEXRF) method to measure low-level impurities on silicon wafers. The presented high-resolution GEXRF technique leads to direct detection limits of about 1012 atoms/cm2. The latter can be presumably further improved down to 107 atoms/cm2 by combining the synchrotron radiation-based GEXRF method with the vapor phase decomposition preconcentration technique. The capability of the high-resolution GEXRF method to perform surface-sensitive elemental mappings with a lateral resolution of several tens of micrometers was probed.

M-SHELL X-RAY PRODUCTION CROSS SECTIONS FOR PIXE APPLICATIONS

M-shell X-ray production cross sections by protons of energies 0.1–4.0 MeV are reported for the most intense Mαβ(M4,5N6,7), Mγ(M3N4,5) and M3O4,5 M-X ray transitions appearing in PIXE spectra. The cross sections have been measured systematically for selected heavy elements between Ta and Th (Z2=73–90). Measured M-X-ray production cross sections were found to be universal with respect of M-shell scaled velocity ξM. The data are compared with available theoretical calculations of M-shell ionization by charged particles based on the plane-wave Born approximation (PWBA) and the semiclassical approximation (SCA), as well as the ECPSSR theory and relativistic RPWBA-BC which are going beyond the first order treatment. Simple parameterization of experimental proton induced M-X-ray cross sections is proposed for PIXE applications. This parameterization, being accurate within ±5%, can be used for precise determination of heavy metal concentrations by PIXE technique.

Multiple ionization effects in low-resolution X-ray spectra induced by energetic heavy ions

Abstract The method of analysis of the multiple ionization effects in low-resolution X-ray spectra induced by heavy ions is described here. It is shown that, by fitting the X-ray spectra measured by a semiconductor detector with the proposed model, which accounts for the multiple ionization effects, the ionization probabilities can be determined as free fitting parameters. This approach is based on the assumption that the intensity distribution of emitted X-ray satellites is approximately described by the binomial distribution parameterized by the ionization probability at the moment of X-ray emission. In particular, we demonstrate that the excited X-ray satellites, when measured by a low-resolution semiconductor detector, appear as the Gaussian profile, which is shifted and broadened with respect to the diagram line. Moreover, we find that both X-ray line shift and width are expressed in terms of the multiple ionization probabilities, as well as the X-ray energy shifts per vacancy. These observations allowed to develop a novel method of X-ray spectra fitting. Detailed discussion of the approximations used in the present approach is given. The method developed, using the calculated Dirac–Fock X-ray energy shifts per vacancy, was applied to determine the multiple ionization probabilities in M- and N-shell by fitting the measured X-ray spectra for L γ (L→N,O) transitions induced by heavy ions in selected high-Z atoms.

PIXE and XRF analysis of honey samples

Abstract The systematic determination of trace-element concentrations in honey samples was done by the PIXE method using a 2 MeV proton beam and by the total reflection XRF method. The different kinds of honey samples were collected in the period of spring–summer in three places of Poland: in the centre of Warsaw (a highly polluted region) and about 100 km east of Warsaw and 70 km southwest of Warsaw (as regions free from industrial and transport pollution). The measured samples have shown that the concentrations of trace elements are similar in the honey samples from these places.

Precision tests of QED in strong fields: experiments on hydrogen- and helium-like uranium

In this contribution, we present an experimental study carried out at GSI Darmstadt devoted to investigation of quantum electrodynamical (QED) effects for the ground states in hydrogen- and helium-like uranium. In the experiment, X-ray spectra following radiative recombination of free electrons with bare and H-like uranium ions (U92+, U91+) were measured at the electron cooler of the ESR storage ring. Utilizing clean and favorable experimental conditions present at the electron cooler, we were able to obtain very accurate values for the ground-state binding energies from the observed X-ray transitions. When compared with theory, our results provide the most stringent test of bound-state QED for one- and two-electron systems in the strong-field regime.

Analysis of Copper Concentration in Human Serum by Application of Total Reflection X-ray Fluorescence Method

The chemotherapy and photon radiotherapy are the most often applied methods in treatment of the cancer diseases because of their effectiveness and high cure rates. Apart from eligible destruction of the tumour, one of the side effects of these treatment methods is possible modification of main and trace element concentration in different human tissues and fluids. In this paper, the copper (Cu) level in human serum was determined by total reflection X-ray fluorescence method in 142 chemotherapy patients and in 44 healthy persons being a control group. The Cu concentration in the chemotherapy group was found to be on the level 1.78 ± 0.909 mg/L, while in the control group, it was 1.08 ± 0.551 mg/L. Performed measurements allowed for calculation of the parameters of copper concentration distribution (mean value, standard deviation, median) for both analysed groups. The theoretical nature of the concentration distribution was tested and found as a log-normal distribution (control group) and a log-stable distribution (chemotherapy group). The copper concentration distributions for both studied group were statistically compared using Kolmogorov-Smirnov test, and the conclusion was that the distributions are statistically different. Serum Cu levels were significantly higher in the chemotherapy group than in the control group. Taking into account the results for the control group, the copper concentration reference quantile ranges in human serum were obtained. The values of the mean, median and other quantiles determined in this case can be applied in two-group comparison studies. The obtained results can be used as a diagnostic tool for chemotherapy patients.

MULTIPLE IONIZATION OF M- AND N-SHELLS IN HEAVY ATOMS BY O, SI AND S IONS

Abstract Multiple ionization in M- and N-shells in solid Au, Bi, Th and U targets was studied for O, Si and S ions of energies 0.4–2.0 MeV/amu. L γ X-rays measured with semiconductor Si(Li) detector were analysed by using a newly developed method of the simultaneous determination of X-ray energy shifts and line broadening caused by the multiple ionization in outer shells. In this approach both X-ray energy shifts and widths are expressed in terms of ionization probabilities and calculated energy shifts per vacancy, allowing thus the unique fitting of the L γ X-rays and determination of ionization probabilities. Derived ionization probabilities for M- and N-shells exhibit universal scaling predicted by the geometrical model (GM) for the ionization probabilities at the zero impact parameter. The influence of time evolution of the vacancies formed in M- and N-shells by ion impact is discussed.