An external milli-beam for archaeometric applications on the AGLAE IBA facility of the Louvre museum

External beam lines have been built on numerous IBA facilities for the analysis of works of art to avoid sampling and vacuum potentially detrimental to the integrity of such precious objects. On the other hand, growing interest lies on microprobe systems which provide a high lateral resolution but which usually work under vacuum. Until recently, the AGLAE facility was equipped with separate external beam and microprobe lines. The need of a better spatial resolution in the external beam mode has led us to combine them into a single system which exhibits numerous advantages and allows the analysis of small heterogeneities like inclusions in gemstones or tiny components of composite samples. The triplet of quadrupole lenses bought from Oxford is used to focus the beam. By using a 0.75 mu m thick Al foil as the exit window, blowing a helium flow around the beam spot and reducing the window-sample distance below 3 mm, a beam size of about 30 mu m can be reached. The experimental setup includes two Si(Li), a HPGe and a Si surface barrier detectors for the simultaneous implementation of PIXE, NRA and RES. The full description of this device is given as well as a few applications to highlight its capability. (C) 1998 Published by Elsevier Science B.V.