Staging of laser-based plasma accelerators using tape-based plasma mirrors*

Laser-based plasma accelerators (LPAs) provide the ability to achieve acceleration gradients for electrons and positrons orders of magnitude greater than conventional accelerators. Previous LPA experiments with this setup have demonstrated electron beams accelerated up to 8 GeV. However, the maximum electron energy that can be reached in a single stage is limited by the energy of the drive laser pulse. In order to produce higher energy electron beams with lasers of reasonable size, multiple acceleration stages must be coupled together. In order to maximize acceleration gradient, the laser energy must be coupled into each acceleration stage in as short a distance as possible. This means maximizing the laser fluence on the coupling optic, and due to the damage threshold of conventional optics, a plasma mirror is required. Initial low electron-capture-efficiency staging experiments at the 100MeV-level were performed using a replenishing tape-based plasma mirror. In this talk we will present analysis on the suitability of this technology for driving high efficiency multi-GeV stages. Tape flatness was measured and improved, and a pointing feedback system implemented to allow for efficient laser coupling into LPA stages. This will enable the demonstration of staging with multi-GeV electron acceleration in two acceleration stages, and lay the foundation for higher energy LPAs.