High Resolution PIXE Research Articles

Foundations and trends of high resolution energy dispersive PIXE (HiRED-PIXE)

High Resolution Particle Induced X-ray Emission, for short HR-PIXE, dates back to 1977 and is, therefore, nearly as old as standard PIXE itself. Until roughly ten years ago, High Resolution PIXE (HR-PIXE) work used only wavelength dispersive spectrometers (WDS). The installation, in 2008, of an X-ray Microcalorimeter Spectrometer, XMS at CTN (ITN at the time) 3MV tandetron, altered this situation and, as can be recognised today, will lead to major changes in PIXE, and open up many possibilities that have been hindered so far. In this work, motives, developments, important breakthrough results obtained until now, and a case study displaying speciation data and complementary information from nuclear magnetic relaxometry, are presented and discussed, showing the full quantitative potential of High Resolution Energy Dispersion PIXE (HiRED-PIXE), in particularly the opening up of the possibility to establish fast and efficient methods for quantitative elemental speciation in unknown samples.

DT2, a PIXE spectra simulation and fitting package

AbstractRecently, a new PIXE code, LibCPIXE, was produced as a variant to the old DATTPIXE package following a simulation‐based approach usually not used in PIXE data handling. This approach required to merge the PIXE data handling code, LibCPIXE to NDF, a well‐known code for handling RBS and other IBA methods data, and showed that complex structures in the samples can dramatically change the observed PIXE yields. A full stepwise process was then undertaken in order to produce a new PIXE data handling code that uses the simulation approach not only to estimate the number of K‐α and L‐α x‐rays emitted by the elements present in structured samples but to fit the entire PIXE energy spectra. This approach is of particular importance for the new high x‐ray energy and high resolution PIXE set‐up being installed at ITN, for the precise interpretation of PIXE spectra from complex targets, and also as a robust basis to relative yield ion energy dependence (RYIED) work discussed elsewhere in this conference. In this communication we present the fitting core for the new DT2 package and discuss its capacity. Copyright © 2008 John Wiley & Sons, Ltd.

CHEMICAL STATE ANALYSIS OF Cr AND Fe BY IN-AIR PIXE USING A CURVED CRYSTAL SPECTROMETER COMBINED WITH A POSITION-SENSITIVE PROPORTIONAL COUNTER

The feasibility of RIKEN high-resolution PIXE system for direct chemical state analysis of 3d transition elements was examined. K β spectra of Cr and Fe from several compounds were measured in air at atmospheric pressure using a crystal spectrometer consisting of a position-sensitive proportional counter and a curved crystal in v. Hamos geometry. Fine structures which reflect the chemical states of Cr and Fe were well recognized with the measuring time of tens minutes.

高速結晶分光PIXEに用いる積層検出器システム

高速結晶分光PIXEに用いる積層検出器システム

IMPROVEMENT IN THE PRECISION AND THE FACILITY OF CHEMICAL SHIFT MEASUREMENTS USING A POSITION-SENSITIVE CRYSTAL SPECTROMETER FOR PIXE

A narrow entrance slit was attached to an in-air high-resolution PIXE system composed of a flat analyzing crystal and a position-sensitive proportional counter. Chemical shift measurements were carried out for Si, P and S Kα1,2 lines from various sample targets. The precision of measurements is much improved compared with that obtained by the position-sensitive crystal spectrometer system without the entrance slit. The new system equipped with the entrance slit does not require exact sample positioning. It is applicable to non-flat targets. Chemical shift measurements are also possible while moving the targets.

DIRECT SPECIATION OF SULFUR IN MARINE SEDIMENT BY HIGH-RESOLUTION PIXE

Chemical shifts of Kα1,2 line of sulfur in marine sediments were measured with in-air high-resolution PIXE in order to examine the possibility of direct speciation of sulfur in such environmental substances. Change of chemical states of sulfur along the depth in the sediments was observed. Oxidation of the sediment samples by air was also examined. Problems to be improved for exact speciation are discussed.

High resolution PIXE using different orders of reflection, Part II

Using high resolution PIXE, the concentration ratio of elements, for which a lower order and a higher order reflection of X-rays are in close vicinity, can be measured without changing the analyzer crystal. An empirical peak-area concentration-ratio calibration curve can be made. The dolomitization degree of limestones has been determined by measuring the third-order Ca and the first-order Mg K α lines. Further element combinations, which can be measured using different reflection orders, are listed. The aspects of analyzer crystal ageing and of the use of heavier projectiles are discussed.

The Mg/Ca ratio determination by high resolution PIXE

Small amounts of Mg in the presence of much Ca can be measured with a PIXE system, using a plane crystal X-ray spectrometer. The dolomitization grade of limestones can be measured with this method. Some possibilities for improving the method are given.