External Microbeam

Personnel Responsible: Carolina Gutierrez Neira

The external microbeam line is used mainly to perform ion beam analysis in art and archaeology research although environmental and material science studies have occasionally been done. The set up of the line combines four detection channels: two X-ray detectors for the PIXE technique, a silicon implanted blind detector, with a helium flow, for RBS, and a gamma detector for PIGE. One of the Si(Li) X-ray detectors is used for the determination of the light elements; a helium stream is applied to optimize the detection in the range of 1.0 – 12 keV. The second one is utilized to measure the trace elements. The particle detector is positioned in Cornell geometry for carrying on RBS analysis. For the PIGE analysis a HPGe detector can be installed temporarily for measuring very light elements like Li, Be, Na, Al or Si.  The line is now provided with a new lanthanum bromide detector which has the same detection efficiency of the HPGe one but is much more compact and can offer a larger solid angle and a resolution which is excellent, amongst the scintillation detectors.

The beam is extracted from the vacuum line through a 0.2 μm thick Si3N4. It is possible to use beams with different size depending of the request of the experiment but in regular operation beams around 50 μm diameter are obtained using the Si3N4 window. The acquisition system allows to acquire simultaneously all spectra (PIXE, RBS and PIGE) as well as complementary information (e.g. images) and to remotely control the sample movement and position.


View of the external beam line setup


Detail of the external microbeam line


Experimental calibration microbeam line


Full-view of the microbeam line