In this work, the Coulomb effects (Coulomb correlations) in pi+pi- pairs produced in p + Ni collisions at 24 GeV=c, are studied using experimental pi+pi- pair distributions in Q, the relative momentum in the pair center-of-mass system (c.m.s.), and its projections Q(L) (longitudinal component) and Q(t) (transverse component) relative to the pair direction in the laboratory system (LS). The major part of the pion pairs ("Coulomb pairs") is produced in the decay of rho, omega and Delta resonances and other short-lived sources. In these pairs, the significant Coulomb interaction occurs at small Q, dominating the pi+pi- interaction in the final state. The minor part of the pairs ("non-Coulomb pairs") is produced if one or both pions arose from long-lived sources like eta, eta ' or from different interactions. In this case, the final state interaction is practically absent. The Q, Q(L), and Q(t) distributions of the Coulomb pairs in the c.m.s. have been simulated assuming they are described by the phase space modified by the known point-like Coulomb correlation function A(C)(Q), corrected for small effects due to the nonpointlike pair production and the strong two-pion interaction. The same distributions of non-Coulomb pairs have been simulated according to the phase space, but without A(C)(Q). In all Q(t) intervals, the experimental Q(L) spectrum shows a peak around Q(L) = 0 caused by the Coulomb final state interaction. The full width at half maximum increases with Q(t) from 3 MeV/c for 0 < Q(t) < 0.25 MeV/c to 11 MeV/c for 4.0 < Q(t) < 5.0 MeV/c. The experimental Q(L) distributions have been fitted with two free parameters: the fraction of Coulomb pairs and the normalization constant. The precision of the description of these distributions is better than 2% in Q(t) intervals 2-3, 3-4, and 4-5 MeV/c and better than 0.5% in the total Q(t) interval 0-5 MeV/c. It is shown that the number of Coulomb pairs in all Q(t) intervals, including the small Q(t) (small opening angles theta in the LS) is calculated with theoretical precision better than 2%. The comparison of the simulated and experimental numbers of Coulomb pairs at small Q(t) allows us to check and correct the detection efficiency for the pairs with small. (0.06 mrad and smaller). It is shown that Coulomb pairs can be used as a new physical tool to check and correct the quality of the simulated events. The special property of the Coulomb pairs is the possibility of checking and correcting the detection efficiency, especially for the pairs with small opening angles.

The DIRAC experiment at CERN investigated in the reaction p(24 GeV/c) + Ni the particle pairs K+K-, pi(+pi)-, and p p over line with relative momentum Q in the pair system less than 100 MeV/c. Because of background influence studies, DIRAC explored three subsamples of K+K- pairs, obtained by subtracting -using the time-of-flight (TOF) technique-the background from initial Q distributions with K+K- sample fractions more than 70%, 50%, and 30%. The corresponding pair distributions in Q and in its longitudinal projection Q(L) were analyzed first in a Coulomb model, which takes into account only the Coulomb final -state interaction (FSI) and assuming pointlike pair production. This Coulomb model analysis leads to a K+K- yield increase of about four at Q(L) = 0.5 MeV/c compared to 100 MeV/c. In order to study contributions from strong interaction, a second more sophisticated model was applied, considering also strong FSI via the resonances f(0)(980) and a(0)(980) and a variable distance r* between the produced K mesons besides Coulomb FSI. This analysis was based on three different parameter sets for the pair production. For the 70% subsample and with the best parameters, 3680 +/- 370 K+K- pairs were found to be compared to 3900 +/- 410 K+K- extracted by means of the Coulomb model. Knowing the efficiency of the TOF cut for background suppression, the total number of detected K+K- pairs was evaluated to be around 40000 +/- 10%, which agrees with the result from the 30% subsample. The K+K- pair number in the 50% subsample differs from the two other values by about three standard deviations, confirming-as discussed in the paper-that experimental data in this subsample is less reliable. In summary, the upgraded DIRAC experiment observed increased K+K- production at small relative momentum Q. The pair distribution in Q is well described by Coulomb FSI, whereas a potential influence from strong interaction in this Q region is insignificant within experimental errors.

This article discusses the advantages of X-ray fluorescence analysis (XRF) techniques for the determination of ash in coal. The quality of coal depends on the amount of ash contained in it. On the other hand, ash causes irreversible environmental damage when using coal as a source of energy. Since coal is considered as the most important source of energy, coal quality is directly related to ash, which correlates with its non-combustible minerals and elements. Some elements such as S (sulfur), Ti (titanium), Ca (calcium), Fe (iron) after burning coal can have an adverse impact on the environment. Thus, we have demonstrated in this study how we can determine the ash content consisting of noncombustible minerals in the composition of coal and, thus, assess the quality of coal using X-ray fluorescence research. It also describes how we can determine coal ash samples using the XRF analyzer 123-1 in online, which is one of the most optimal methods in nuclear physics.

The article studies the elemental composition of the fillers (polytetrafluoroethylene and carbon nanopowder) of the polymer composite depending on various concentrations of fillers and electron irradiation and modified polytetrafluoroethylene (PTFE). The elemental composition of the fillers and their distribution over the depth of the polymer composite and modified polytetrafluoroethylene were studied by X-ray fluorescence analysis (XRFA) and confocal micro-X-ray analysis. X-ray spectra of the polymer composite and modified polytetrafluoroethylene were obtained. It has been established that an increase in the concentration of one component and an irradiation dose leads to a weakening of the intensities of the spectra of the polymer composite and modified polytetrafluoroethylene.

Ponte Academic JournalMar 2019, Volume 75, Issue 3 DETERMINATION OF SULPHUR AND ASH CONTENTS IN THE COAL BY X-RAY FLUORESCENCE METHODAuthor(s): Baimolda D. ,Cechak T., Yerzhenbek B, Tlebaev K.B.J. Ponte - Mar 2019 - Volume 75 - Issue 3 doi: 10.21506/j.ponte.2019.3.8 Abstract:Coal is a very heterogeneous solid originating mainly from plant material. Coal is a major source of energy and its quality also depends on its elemental composition. Some elements present in coal can be environmentally hazardous when the coal is burned. In recent years, in the countries using a coal as the main source of energy the issue in the field of environment and ecology has become much stronger than in previous years. The international community began to demand tough measures in the field of non-proliferation of air pollution from the combustion of coal carbon dioxide and other toxic gases in the air. In this case, along with the determination of physical and chemical properties of coal and coal ash, there are quickly need to identify some hazardous elements as sulphur, titan and ash that is harmful to the environment. To fulfill such demands and needs recent years have seen rapid developments and applications of x-ray fluorescence (XRF) techniques in the coal industry. This study concerns sulphur and ash contents of coal samples from Mongolia and Czech Republic by using XRF, which offers several unique advantages over other analytical methods. Download full text:Check if you have access through your login credentials or your institution Username Password

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π^{+}π^{-} atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1  μm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n_{A}^{L}=436_{-61}^{+157}|_{tot}, the lifetime of the 2p state is found to be τ_{2p}=(0.45_{-0.30}^{+1.08}|_{tot})×10^{-11}  s, not contradicting the corresponding QED 2p state lifetime τ_{2p}^{QED}=1.17×10^{-11}  s. This lifetime value is three orders of magnitude larger than our previously measured value of the π^{+}π^{-} atom ground state lifetime τ=(3.15_{-0.26}^{+0.28}|_{tot})×10^{-15}  s. Further studies of long-lived π^{+}π^{-} atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like π+π− atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm and got broken up in the 2.1 μm thick platinum foil. Analysing the observed number of atomic pairs, nA = 436 +157 −61 ∣∣∣ tot, the lifetime of the 2p state is found to be τ2p = (0.45+1.08 −0.30 ∣∣∣ tot) · 10 −11s, not contradicting the corresponding QED 2p state lifetime τ 2p = 1.17 · 10−11s. This lifetime value is three orders of magnitude larger than our previously measured value of the π+π− atom ground state lifetime τ = (3.15+0.28 −0.26 ∣∣∣ tot) · 10−15s. Further studies of long-lived π+π− atoms will allow to measure energy differences between p and s atomic states and so to determine ππ scattering lengths with the aim to check QCD predictions.

The presence of heavy chemical elements in old pigments is possible to identify in historical paintings using Xray fluorescence analysis (XRF). This is a non-destructive analytical method frequently used in examination of objects that require in situ analysis, where it is necessary to avoid damaging the object by taking samples. Different modalities are available, such as microanalysis, scanning selected areas, or depth profiling techniques. Surface scanning is particularly profitable since 2D element distribution maps are much more understandable than the results of individual analyses. Information on the layered structure of the painting can be also obtained by handheld portable systems. Results presented in our paper combine 2D element distribution maps obtained by scanning analysis, and depth profiling using conventional XRF. The latter is very suitable for objects of art, as it can be evaluated from data measured with portable XRF device. Depth profiling by conventional XRF is based on the differences in X-ray absorption in paint layers.The XRF technique was applied for analysis of panel paintings of the Master of the St George Altarpiece who was active in Prague in the 1470s and 1480s. The results were evaluated by taking micro-samples and performing a material analysis.

The DIRAC spectrometer installed at CERN PS was upgraded in order to study simultaneously A(2 pi) and A(pi K) atoms, namely the bound states of two pi mesons, and of pi and K mesons, respectively. The detector system can now accept a high intensity beam of 2-6 x 10(11) primary protons per second. The electronics and the data-acquisition system can handle a very large amount of data to identify pi, K, p, e and mu, allowing the selection of pi pi and pi K pairs in the offline analysis. The resolution of the longitudinal and transverse components of the relative momentum Q of each meson pair in their center-of-mass system with respect to the direction of the pair was substantially improved. The analysis of their distributions allowed an reliable separation between the meson pairs originating from hadronic atoms and the backgrounds permitting the measurement of the lifetimes of hadronic atoms in the ground state and pi-pi, pi-K s-wave scattering lengths. The upgraded setup also allowed the study of the long-lived excited states of pi pi atoms. (C) 2016 Elsevier B.V. All rights reserved.

Experiment DIRAC at CERN PS detects 349 ± 62 pairs from π−K+ and π+K− atoms and makes observation of exotic atoms consist of pion and kaon. It allows to measure a difference of S-wave pion-kaon scattering length with isospin 1/2 and 3/2: |a01/2−a03/2|. Values of pion-kaon scattering lengths are predicted in a frame of ChPT and LQCD. Therefore investigation of π−K+ and π+K− atoms gives possibility to check these predictions for simplest hadronhadron system with s-quark.

B. Adeva a, L. Afanasyev b, A. Anania c, S. Aogaki d, A. Benelli e, V. Brekhovskikh f, T. Cechak e, M. Chiba g, P. Chliapnikov f, P. Doskarova e, D. Drijard h, A. Dudarev b, M. Duma d, D. Dumitriu d, D. Fluerasu d, A. Gorin f, O. Gorchakov b, K. Gritsay b, C. Guaraldo i, M. Gugiu d, M. Hansroul h, Z. Hons j, S. Horikawa k, Y. Iwashita l, V. Karpukhin b, J. Kluson e, M. Kobayashi m, V. Kruglov b, L. Kruglova b, A. Kulikov b, E. Kulish b, A. Kuptsov b, A. Lamberto c, A. Lanaro n, R. Lednicky o, C. Mariñas a, J. Martincik e, L. Nemenov b,h, M. Nikitin b, K. Okada p, V. Olchevskii b, V. Ovsiannikov q, M. Pentia d, A. Penzo r, M. Plo a, P. Prusa e, G. Rappazzo c, A. Romero Vidal a, A. Ryazantsev f, V. Rykalin f, J. Saborido a, J. Schacher s,∗, A. Sidorov f, J. Smolik e, F. Takeutchi p, L. Tauscher t, T. Trojek e, S. Trusov u, T. Urban e, T. Vrba e, V. Yazkov u, Y. Yoshimura m, M. Zhabitsky b, P. Zrelov b

After observing and investigating the double-exotic (adouble-exotic atom is a bound system, in which both oppositely charged components are unstable particles like mu, pi, K,...) pi(+)pi(-) atom with the ground state lifetime tau of about 3 x10(-15)s, the upgraded DIRAC experiment at the CERN PS accelerator observes for the first time long-lived states of the same atom with lifetimes of about 10(-11)s and more. The number of characteristic pion pairs resulting from the breakup (ionisation) of long-lived pi(+)pi(-) atoms amounts to 436 +/- 61, corresponding to a signal-to-error ratio of better than 7 standard deviations. This observation opens a new possibility to measure energy differences between p and s atomic states and so to determine pi pi scattering lengths. (C) 2015 CERN for the benefit of the DIRAC Collaboration. Published by Elsevier B.V.

This paper provides an overview of analytical methods frequently used to identify terrestrial radionuclides in samples. While radioactivity is normally measured through the ionising radiation produced during the spontaneous decay of unstable atoms, selected radionuclides or their chemical elements can be quantified with instrumental techniques based on stimulated emission or counting of atoms. The advantages and disadvantages of these analytical methods are discussed. Particular attention is paid to X-ray fluorescence analysis of materials containing uranium and thorium. It is also possible to determine the area distributions of these chemical elements in samples with the use of scanning X-ray fluorescence systems.

X-ray fluorescence analysis uses ionizing radiation to study the elemental composition of materials. It is widely used for many purposes, including studies of various cultural and historic relicts and objects of art. This paper summarizes our experience with X-ray fluorescence analysis and attenuated total reflectance Fourier transform infrared spectroscopy in investigating historical photographs by means of portable spectroscopic devices. The results of these measurements provide information about the composition of historical photographs and their toning. They can be used for comparing the processes used in fabricating the photographs, for assessing the quality of the paper and, in many cases, for information about how to repair damaged parts.

Individual monitoring services for external radiation were tested in the Czech Republic. The results of the tests show that they are dosimetry systems authorized and regularly tested in the Czech Republic having outliers for low energy region and angle of 50 degree and greater. With the highest probability, it can be stated that the processing equipment does not determine the angle of exposure reliably. These cases may have caused overestimations of Hp(10) in the special conditions occurring e.g. in interventional radiology and cardiology procedures.

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.

The DIRAC experiment at CERN investigated in the reaction p(24 GeV/c)+Ni the particle pairs K+K−,π+π− and pp̄ with relative momentum Q in the pair system less than 100 MeV/c. Because of background influence studies, DIRAC explored three subsamples of K+K− pairs, obtained by subtracting – using time-of-flight (TOF) technique – background from initial Q distributions with K+K− sample fractions more than 70%, 50% and 30%. The corresponding pair distributions in Q and in its longitudinal projection QL were analyzed first in a Coulomb model, which takes into account only Coulomb final state interaction (FSI) and assuming point-like pair production. This Coulomb model analysis leads to a K+K− yield increase of about four at QL = 0.5 MeV/c compared to 100 MeV/c. In order to study contributions from strong interaction, a second more sophisticated model was applied, considering besides Coulomb FSI also strong FSI via the resonances f0(980) and a0(980) and a variable distance r∗ between the produced K mesons. This analysis was based on three different parameter sets for the pair production. For the 70% subsample and with best parameters, 3680± 370 K+K− pairs was found to be compared to 3900± 410 K+K− extracted by means of the Coulomb model. Knowing the efficiency of the TOF cut for background suppression, the total number of detected K+K− pairs was evaluated to be around 40000± 10%, which agrees with the result from the 30% subsample. The K+K− pair number in the 50% subsample differs from the two other values by about three standard deviations, confirming — as discussed in the paper — that experimental data in this subsample is less reliable. In summary, the upgraded DIRAC experiment observed increased K+K− production at small relative momentum Q. The pair distribution in Q is well described by Coulomb FSI, whereas a potential influence from strong interaction in this Q region is insignificant within experimental errors.

The research and development of new VUV scintillators includes also LuLiF4 single crystals doped by Nd3+. Due to their lower light yield, the Gd3+ codoping is studied as a tool to improve an energy transfer from the host to Nd3+ emission centers and increase the light yield consequently. Emission spectra and decays with respect to the different concentration of Gd and Nd ions are studied and discussed as well.

An overview of absorption and luminescence characteristics of Nd3+ and Gd3+ centers in a LiLuF4 single crystal host is provided. Single crystals doped with the above rare earth ions were prepared by micropulling-down technique in the form of rods a few cm long with a diameter of about 2 mm. Excitation and emission spectra and fast decay kinetics in VUV and UV spectral regions were measured at room temperature. The observed absorption and emission peaks are due to the 5d-4f and 4f-4f optical transitions of Nd3+ and Gd3+ centers. Concentration dependence of the decay kinetics is also discussed. (C) 2012 Elsevier B.V. All rights reserved.

The research and development of new VUV scintillators includes also LuLiF4 single crystals doped by Nd3+. Due to their lower light yield, the Gd3+ codoping is studied as a tool to improve an energy transfer from the host to Nd3+ emission centers and increase the light yield consequently. Emission spectra and decays with respect to the different concentration of Gd and Nd ions are studied and discussed as well.