Confocal spectroscopy

Scheme of confocal geometry set-up

A series of slits and quadrupole magnets in a nuclear microprobe allow us to focus proton/paricle beam to a micrometer level and we can analyse objects with the so called µ-PIXE method. With the help of deflection magnet we can scan the surface area and at each point where the beam hits the target the spectra is collected. In this way we can obtain 2D images and 2D elemental distribution of samples with micron lateral resolution.
The confocal arrangement is achieved by alignment of the proton microbeam focal plane to the focal point of the polycapillary half-lens that is mounted on the snout of the Si(Li) spectrometer. In this way, the combination of a great lateral resolution obtained with the microbeam and the polycapillary's ability to deduce the signal from the depth allows us to analyse thin films, multilayered samples and particles in special 3D samples.
There are two measurement possibilities in confocal µ-PIXE - sample or beam scanning mode. In sample scanning mode the beam is kept stationary in one point, while the target is moved forward and backwards from the incoming beam - in this way, depth profiles can be extracted from the signal. In the beam scanning mode, we use great lateral scanning capabilities of the microbeam on the stationary target - it is ideal for acceptance volume characterization or even depth profiling. With the combination of both ways, we can analyse three-dimensional objects.

Scheme of confocal modes


[1] A-G. Karydas, D. Sokaras, C. Zarkadas, N. Grlj, P. Pelicon, M. Žitnik, R. Schütz, W. Malzer, B. Kanngießer: 3D Micro-PIXE - a new technique for depth-resolved elemental analysis. J. Anal. At. Spectrom. 22 (2007) 1260
[2] M. Žitnik, P. Pelicon, N. Grlj, A-G. Karydas, D. Sokaras, R. Schütz, B. Kanngießer: Three-dimensional imaging of aerosol particles with scanning proton microprobe in a confocal arrangement. Appl. Phys. Lett. 93 (2008) 094104
[3] D. Sokaras, A-G. Karydas, W. Malzer, R. Schütz, B. Kanngießer, N. Grlj, P. Pelicon, M. Žitnik: Quantitative analysis in confocal µ-PIXE - general concept and layered materials. J. Anal. At. Spectrom. 24 (2009) 611
[4] T. Wolff, I. Mantouvalou, W. Malzer, J. Nissen, D. Berger, I. Zizak, D. Sokaras, A-G. Karydas, N. Grlj, P. Pelicon, R. Schütz, M. Žitnik, B. Kanngießer: Performance of a polycapillary halflens as focusing and collecting optics - a comparision. J. Anal. At. Spectrom. 24 (2009) 669
[5] M. Žitnik, P. Pelicon, K. Bučar, N. Grlj, A-G. Karydas, D. Sokaras, R. Schütz, B. Kanngießer: Element-selective three-dimensional imaging of microparticles with a confocal micro-PIXE arrangement. X-Ray spectrom. (accepted in publication)
[6] M. Žitnik, N. Grlj, P. Vaupetič, P. Pelicon, K. Bučar, D. Sokaras, A-G. Karydas, B. Kanngießer: 3D-reconstruction of an object by means of a confocal Micro-PIXE. J. Anal. At. Spectrom. (accepted in publication)

Contact: Nataša Grlj

Last updated: 01/22/2014