Phosphorus in cryospheric microinvertebrates: a first insight into glacier and non-glacier tardigrades and rotifers by particle induced X-ray emission (PIXE)

Editorial

Standardisation of the ion beam facility at Chandigarh cyclotron for simultaneous PIXE and PESA analysis

The Second International Conference on Particle Induced X-ray Emission (PIXE) and its analytical applications was held in Lund, Sweden, June 9-12, 1980. About a hundred papers were presented, including seven invited talks (PIXE and particle scattering, microbeam analysis (2), applications to aerosols (2) and biological samples (2)). The main impression left by the conference was that both the PIXE method and its applications are in a phase of fast development. Considerable effort has successfully been devoted to optimizing the basic PIXE technique. Also the great advantage of simultaneously getting information about lighter elements and sample mass was reported to have been successfully employed in routine analyses. PIXE, which was initially considered to be a method mainly for thin samples, has also been shown to be competitive for a variety of thick samples. Consequently there were several papers dealing with problems characteristic of thick sample analysis. In this context, external beam analysis was also thoroughly discussed. Charged particle microprobes seem to be very attractive and several investigators reported progress on microprobe development and very interesting results of applied work. It is gratifying to note the increasing interest shown by non-physisists in using PIXE. These activities have greatly contributed to the fact that PIXE has now in a few areas left the phase of feasibility tests. E.g. an imposing amount of data from aerosol studies was presented.

Urbanization and industrial growth have deteriorated air quality and are major cause to air pollution. Air pollution through fine and ultra-fine particles is a serious threat to human health. The source of air pollution must be known quantitatively by elemental characterization, in order to design the appropriate air quality management. The suitable methods for analysis the airborne particulate matter such as nuclear analytical techniques are hardly needed to solve the air pollution problem. The objectives of this study are to apply the nuclear analytical techniques to airborne particulate samples collected in Bandung, to assess the accuracy and to ensure the reliable of analytical results through the comparison of instrumental neutron activation analysis (INAA) and particles induced X-ray emission (PIXE). Particle samples in the PM 2.5 and PM 2.5-10 ranges have been collected in Bandung twice a week for 24 hours using a Gent stacked filter unit. The result showed that generally there was a systematic difference between INAA and PIXE results, which the values obtained by PIXE were lower than values determined by INAA. INAA is generally more sensitive and reliable than PIXE for Na, Al, Cl, V, Mn, Fe, Br and I, therefore INAA data are preffered, while PIXE usually gives better precision than INAA for Mg, K, Ca, Ti and Zn. Nevertheless, both techniques provide reliable results and complement to each other. INAA is still a prospective method, while PIXE with the special capabilities is a promising tool that could contribute and complement the lack of NAA in determination of lead, sulphur and silicon. The combination of INAA and PIXE can advantageously be used in air pollution studies to extend the number of important elements measured as key elements in source apportionment. Received: 20 November 2010; Revised: 09 August 2011; Accepted: 15 August 2011

In March 1999, electrostatic accelerator, Tandetron (Model 4117MC, High Voltage Engineering Europe Co.) was installed in the Electrostatic Accelerator Building for PIXE (Particle Induced X-ray Emission) analysis. The accelerating voltage is 0.4 to 1.7MV, and the maximum beam current is 5μA at 3.4MeV. This system has three beam ports for different types of PIXE analysis: normal, micro-beam and in-air. The first beam port is used for normal PIXE. Since two types of X-ray detecting device, Si ( Li ) and CdZnTe detectors, are available here, elements from Na ( Z =11) to U ( Z =92) are detectable. Fifteen samples can semi automatically be measured at one time using a proton beam of optical beam size from 0.5 to 2.0 mm at 100 nA beam current. A quadrupole triplet magnet (Model OM2000, Oxford Micro beams, Ltd.) attached to the second beam port produces a proton micro-beam of square shape less than 1μ m ×1μ m . Micro-beam scanning PIXE analysis is carried out with this beam at 50pA current and scanning area up to 2.0mm square. The in-air PIXE analysis is performed using the third beam port. The operation of this machine has been scheduled to start from April 2000 and is controlled by Division of Technology and Safety. Some results preliminarily obtained are also shorn.

The production of particle induced X-ray emission (PIXE) is an important physical effect that is not yet accurately modelled in Geant4. After providing a brief overview of Geant4 implementations of PIXE up to now, we describe our current effort for improving the Geant4 implementation of PIXE. This research and development activity is part of a larger effort addressing more general aspects of particle transport in Geant4. We illustrate the status of our work by applying a prototype implementation of Geant4 PIXE to a study of the passive shielding of the X-ray detectors of the German eROSITA telescope on the upcoming Russian Spectrum-X-Gamma space mission.

Whole blood from patients undergoing Coronary Artery Bypass Grafting (CABG) operations was separated into leukocyte subfractions of polymorphonuclearcytes (PMN) and peripheral blood mononuclear cells (PBMC). Blood samples were collected and analyzed at various timepoints to determine the elemental composition to provide a better understanding of recovery mechanisms and to indicate complications that may occur post-operatively. Proton induced X-ray emission (PIXE) analysis and Rutherford backscattering spectrometry (RBS) using the University of Surrey microprobe was employed to determine the concentrations of a range of elements. Accurate two-dimensional PIXE analysis however, requires knowledge of the sample matrix composition. These samples, on the other hand, showed varying thickness, lacked matrix homogeneity and displayed non-uniform trace element distribution. This paper discusses the results and problems associated with routine PIXE analysis and demonstrates the potential ability of ion beam analysis (IBA) depth profiling software, previously unused in PIXE analysis, to model a RBS spectrum of inhomogeneous, multi-layered samples prior to performing PIXE analysis.

Size-resolved aerosol monitoring for PM10, PM2.5, and PM1.0 was performed to qualify and quantify the elements and ions by using proton induced X-ray emission (PIXE), inductively coupled plasma optical emission spectrometry (ICP-OES), and ion chromatography (IC) analysis. Time-resolved aerosol samplings based on 2-hour and 14-hour intervals were carried out during daytime and nighttime, respectively. Physical and chemical properties of size-resolved aerosols were investigated to characterize air quality in the national park area of Gyeongju, Korea. The PIXE and ICPOES methods made elemental mass of Al, Si, S, K, Ca, Ti, Cr, Fe, Sr, and Pb. And ions of Na+, NH4+, Ca2+, Cl−, NO3−, and SO42− were analyzed by the IC method. The mass concentrations of Si, S, Ti, and Pb determined by PIXE showed relatively good correlation with those determined by ICP-OES. But Fe and Sr had worse correlations with an average R2 of 0.4703 and 0.4825, respectively. The PIXE method was a good alternative to measure chemical species of Al, Si, S, K, Ca, Ti, Cr, and Pb for size-resolved aerosols except Fe and Sr in this study. The average relative errors of sizeresolved elements for 2-hour and 14-hour interval collections were 10.1±5.7% (0.1–28.3%) and 9.9±7.7% (1.3–38.4%). Ammonium sulfates (AS), mineral dust (MD), and sea salt (SS) aerosols were reconstructed from the elements determined by PIXE and ICP-OES and ions obtained by IC. The mass concentration of MD was calculated with crustal elements of Al, Si, Ca, Ti, and Fe, which are associated with soil erosion. The average relative error of MD was the lowest value of 0.8% in the PM10 regime and the highest value of 10.0% in the PM1.0 regime. The average relative errors of AS for PM10, PM2.5, and PM1.0 determined by PIXE, ICP-OES, and IC showed relatively lower values of 0.8–5.7%, 1.7–5.9%, and 3.3–8.3%, respectively. The average mass concentrations of AS, MD, and SS of PM10, PM2.5, and PM1.0 except submicron SS determined by PIXE were comparable to those determined by ICP-OES and IC within the acceptable relative errors.

Analysis of atmospheric aerosols by PIXE: the importance of real time and complementary measurements

PIXE and RIXRF comparison for applications to biological sample analysis

In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on or inside SiC is discussed. Optimization of PIXE acquisition parameters was performed using as reference, a thin Al film (2.5 nm) thermally evaporated onto silicon carbide substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.02 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 µm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9x1020 at/cm3 in good agreement with SIMS measurements, and the LOD was estimated to be 6x1018 at/cm3.

On the accuracy of element concentrations and masses of micron sized samples determined with the Heidelberg proton microprobe

Proton induced X-ray emission (PIXE) and atomic absorption spectroscopy (AAS) were used for vanadium determination in animal tissues. The vanadium concentration levels were determined in blood, kidneys and livers taken from rats. Two groups of the animals were treated with different diets. The diet for the first group was supplemented with vanadium compounds while the diet for the second one was assumed to be a “normal” diet. The second group was treated as control. In order to achieve the best minimum detectable limit (MDL)1 the samples were subject to a special sample preparation procedure. Blood and kidneys were mineralized with an APDC compound. The mineralization process was performed according to the procedure described previously.2 The application of PIXE3 is very useful for different types of samples. PIXE measurements were performed with a proton beam at the Institute of Nuclear Physics in Cracow, Poland while the AAS measurements were done at the Institute of Molecular Biology, Jagiellonian University, Poland. The concentration levels of vanadium in blood and kidneys are compared and discussed. There were no significant statistical differences between results of vanadium concentration levels determined by the abovementioned techniques. The PIXE technique had the advantage over the AAS technique of giving a broad spectrum of trace elements analyzed in a single measurement. Therefore with the help of sample preparation procedure the application of the PIXE method seems to be suitable for such analyzes.

Limited angle STIM and PIXE tomography of single cells

Trace elemental analysis of Indian natural moonstone gems by PIXE and XRD techniques