New plant for fabricating carbon stripper foils by laser plasma ablation deposition

Abstract

Our theory on the optimum strength of carbon stripper foils with respect to heavy ion induced irradiation damage at tandem energies was confirmed when newly developed carbon foils with isotropically distributed nanocrystals were tested. The new preparation method is based on a hot carbon plasma induced by 10 ns light pulses with a power density of up to 30 GW/cm 2 from a Nd:YAG laser. In order to prepare the so-called lpa-foils (carbon stripper foils prepared by laser plasma ablation deposition) in series production a new ultrahigh vacuum box coater was installed. This system offers a working pressure of about 10 −6 Pa and a substrate area of about 1000 cm 2, which means 100–200 stripper foils per charge depending on the size of the stripper frame. A new pulsed Nd: YAG laser with a repetition rate of 50 Hz was installed at the box coater in order to shorten the deposition time. A status report of the adaptation of the lpa-process to the new setup is presented in detail.