PMMA melting under proton beam exposure

Experiments on 50 μm thin PMMA sheets have been performed using a homogeneous 2 MeV proton beam of 5 mm diameter. The irradiations have been carried out at the Debrecen nuclear microprobe facility. For the characterization of the samples DIC microscopy and Twyman-Green interferometry have been used. It was found that the samples melted at a beam intensity dependent critical dose. Numerical calculations including heat transport and heat radiation corroborated the experimental results.