Enhanced PIXE yields from insulated metal targets

PIXE studies on pure metal targets surrounded by insulating material produced enhanced X-ray yields at comparatively low proton energies. Specially prepared metal discs of selected transition elements were embedded in Macor target holders and irradiated with 700 keV protons. Improved X-ray yields of up to more than 300% were observed. It was found that the enhanced yields were affected by the incident beam current due to a 'leakage' effect. The recorded time-dependent spectra showed similar charge build-up and discharge patterns as those originally obtained for non-conducting samples. A possible mechanism for the enhancement is discussed. (author)