Chemical shift measurements of chlorine K X-ray spectra using a high-resolution PIXE system

Abstract A high-efficiency high-resolution wavelength-dispersive spectrograph with a von-Hamos configuration was developed for chemical state identification of elements in environmental samples using PIXE analysis. To evaluate the performance of this system, chlorine K X-ray spectra for NaCl, NH 4 Cl and polyvinylchloride (PVC) targets were measured and compared. Also, to study the applicability to environmental mixed samples, mixtures of NaCl and NH 4 Cl with different mixing ratios were measured. Through observation of Cl Kα 1 X-ray from NaCl, the energy resolution of the system was determined to be 1.1 eV. For the NaCl sample, a Kβ x line was observed at an energy, which is higher than that of the Kβ main peak by 2 eV, whereas no Kβ x emission was observed for the NH 4 Cl sample. The chemical shift of the Kβ main peak for PVC relative to that for NaCl was about 1.2 eV. For NaCl–NH 4 Cl mixture targets, the relative intensity of Kβ x satellite to the Kβ main line provided an indication of mixing ratio. Energies and relative intensity of Cl Kβ X-ray satellites for NaCl and NH 4 Cl samples calculated by a simple molecular-orbital method agreed only qualitatively with the experimental results.