The positron source is a vital system of the ILC. The conversion target that yields about 10 14 positrons per second will undergo high peak and cyclic load during ILC operation. In order to ensure stable long term operation of the positron source the candidate material for the conversion target has to be tested. The intense electron beam at the Mainz Microtron (MAMI) provides a good opportunity for such tests. The first results are presented for Ti6Al4V which is the candidate material for the positron conversion target as well as for the exit window to the photon beam absorber.

In order to build a positron source for the ILC, a high energy density irradiation is needed to test the used materials. At the MAMI injector linear accelerator (ILAC) such a radiation can be provided at different electron energies. With a macro pulsed source it is possible to imitate a year-long radiation at the ILC within several hours. Small transverse beam sizes need to be provided with the focusing system and be measured at high beam currents using transition radiation and beam loss measurements on pin holes. MOTIVATION The international linear collider (ILC) is a planned electron-positron-collider with a length of about 31 km and a center of mass energy of 500 GeV. The machine will operate in a pulsed mode with a time structure of 1 ms long bunch trains and a repetition rate of 5 Hz (Fig. 1). In order