Ion Induced X-ray Emission Research Articles

Applications of simultaneous ion backscattering and ion-induced X-ray emission

Simultaneous ion backscattering and ion-induced X-ray emission ( E x ⪰ 300 eV ) analyses have been performed using helium ions as probes of the first few hundred nanometers of various materials. These studies serve as a demonstration of the complementary nature of the two types of information obtained. Uncertainties associated with each of the individual techniques were reduced by performing both analyses. The pricipal advantages of simultaneous analyses over sequential analyses have been delineated.

Retention of Ions Implanted at Non-Normal Incidence

ABSTRACTFuture applications of ion implantation require a knowledge of how the retention of implanted ions varies with angle of ion incidence. In this work the retention of 150-keV Ar,Ti,Cr,and Ta ions in AISI-M50 and 52100 bearing steels was measured for incidence angles up to 60° off normal. Fluences between 3×1015 and 3×1017/cm2 were used, typically on 3/8” diameter cylindrical samples. Retention was measured for Ar, Ti, and Cr by ion induced x-ray emission and for Ta by backscattering of He ions. Range and sputtering parameters needed for model calculations were experimentally determined from Ta-implanted thin Fe film samples. Generally, at the low-fluence limit a near-cos θ dependence obtained while at the high-fluence limit a (cos θ)8/3 dependence applied where θ is the angle between the sample normal and the beam direction.

On the possibility of immediate analysis of chlorine and sulfur in air by argon ion induced X-ray emission

Inner shell ionization of elements ranging from Al to Ar by energetic Ar ions occurs with high efficiency as a consequence of electron promotion via quasi-molecular orbitals formed during the ion-atom collision. This allows the selective excitation of characteristics X-ray emission of these elements in various media and their detection at low concentrations. Particularly for the analysis of Cl and S in polluted atmospheres gas-target measurements of the cross sections for X-ray production by 0.5–6 MeV Ar ions have been performed. Optimal experimental conditions and sensitivity limits for the detection of these elements are deduced from the measurements.

Trace element detection by high energy heavy ion induced X-ray emission

Argon ions from the Van de Graaf isochronous cyclotron for heavy ions (VICKSI) at Berlin were used to bombard targets containing various elements, originating from environmental and biological studies or prepared as calibrating standards. Emitted X-rays from various target backings were investigated. Background and detection sensitivity were compared with XRF and PIXE results on the same targets.

Argon ion induced X-ray analysis of silicon and chlorine in cadmium telluride

Argon ion induced X-ray emission has been used for analysis of Si and Cl present at low concentrations in CdTe crystals. The influence of zone melting on the distribution of these elements along the crystal is examined.

Depth profile measurements of copper in silicon by ion-induced x-ray emission

Depth profile measurements of copper in silicon by ion-induced x-ray emission

Trace analysis in cadmium telluride by heavy ion induced x-ray emission and by SIMS

The possibilities of using both selective heavy ion induced X-ray emission and secondary ion mass spectroscopy (SIMS), for the identification of impurities present at low concentrations in cadmium telluride are examined. The relative concentrations of the impurities along CdTe crystals have been determined by exciting the X-ray emission of the elements in several slices with Ar and Kr ions and by comparing the relative characteristic X-ray emission yields. As a consequence of the quasimolecular inner shell ionization mechanism in heavy ion-atom collisions, Ar and Kr ions allow a strong excitation of the main impurities seen by SIMS, namely Si, Cl and Ge, As, with only a minor contribution of Cd and Te. From the changes of the concentrations of the various impurities along the crystal, informations about segregation coefficients and compensation can be obtained.

Application of Ion-Induced X-Ray Emission for the Measurement of Stopping Powers

The method for measuring the stopping power of materials for charged particles using ion-induced x-ray emission is described in detail, and the results for 100-keV protons on yttrium and samarium are presented to exemplify the method. By utilizing a lithium-drifted silicon detector, the thickness and uniformity of the stopping film can be monitored simultaneously with the collection of stopping power data. In addition, it will be shown that the incorporation of a backscattering spectrometer with the ion-induced x-ray system can yield two independent measurements of the energy loss in the stopping film, and at the same time detect impurities that might be present in the film.

Measurement of stopping powers using ion-induced X-ray emission

Stopping powers of 100 keV protons in thin films of Sc, Ni, Cu, and Ge which have been vacuum evaporated on thick substrates are measured by observing the characteristic X-rays generated in the substrate. The condition of the stopping film is monitored simultaneously with the collection of stopping power data by the detection of characteristic X-ray emission from the stopping film.

Trace element analysis by ion induced X-ray emission spectroscopy

Abstract K and L X-ray emission rates for 37 elements and continuous background radiation from a thin carbon matrix produced by bombardment with protons of 1.5, 2, 3, and 4 MeV have been investigated. K-shell ionization cross sections for 25 elements for 2 MeV proton bombardment, minimum detection limits through the periodic system in the ppm range and optimum proton energies for highest sensitivity for a given element have been extracted from these measurements. 16O-ions turn out to be much less sensitive than protons of the same velocity. Two examples of applications to mineralogical and environmental problems are given.

Trace elemental analysis by heavy ion induced x-ray emission

Trace elemental analysis by heavy ion induced x-ray emission

Angular distribution measurements of sputtered atoms with characteristic X-ray emission

Polished polycrystalline metal targets have been bombarded by 130, 300 and 1000 keV Ar +-ions at normal and oblique angles of ion incidence. The sputtered material has been collected on a LN 2-cooled stainless steel ring and the angular distribution has been analysed by ion induced X-ray emission. The target erosion ranged between 1 and 8 μm and has been investigated with a scanning electron microscope. Most of the emission profiles have a Gaussian shape and are almost symmetrical to the target normal even for oblique ion incidence. The angular distributions of Cu and Au show some dose dependence which may be related to the development of surface structures. For oblique ion incidence an anisotropy, which is specific for the target material, is observed. It is caused by the anisotropy of the primary atoms and it might be influenced by resputtering.