FOCUSED MICROBEAM SINGLE EVENT WITH A SCINTILLATING FOIL TRIGGER AND MAGNETIC BLANKING

The focused proton microbeam of the Laboratori Nazionali di Legnaro – (Italy) has been upgraded to perform the so called "single event physics". For this purpose, we implemented a trigger which recognises the crossing of a single proton and a beam blanking system. The trigger consists of the light signal coming from a scintillating plastic blade and read by a pair of photomultipliers, while the beam deflection is induced by a magnetic raster system, usually employed in elemental mapping. In spite of its slowness, the last device proves suitable, owing the very low particle rate we were able to achieve. Early tests are described here, during which regular matrices of etched nuclear tracks were produced on polymer CR39 foils. Although, as far as efficiency and spot size are concerned, performance is still far from being satisfactory, we believe this procedure for single event studies to be practicable.