At MTA Atomki the RBS technique is available in vacuum. The lateral resolution is excellent, down to the micron range. The thickness of a given layer is measured by dedicated RBS analysis, irradiating the sample with a He+ beam and detecting the energy of the backscattered particles. For heritage materials, a typical application is to measure the thickness of gold on gilded objects.
The RBS technique is applied at the Scanning Nuclear Microprobe (Oxford Microbeams) which was built at the 0°beam line of our 5 MV single ended vertical Van de Graaff accelerator. A possible arrangement: An ORTEC-type surface barrier silicon detector (‘‘ULTRA’’ Ion-Implanted, 50 mm2 sensitive area and 25 keV system energy resolution) is used. The detector is placed at a scattering angle of 165° at Cornell geometry.
- I. Balta, L. Csedreki et al. Ion beam analysis of golden threads from Romanian medieval textiles. Nuclear Instruments and Methods in Physics Research B 348 (2015) 285-290.