Dresden 2017 – scientific programme

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 1: New Accelerator Concepts I

AKBP 1.5: Talk

Monday, March 20, 2017, 16:00–16:15, MOL 213

Development and In Situ - Characterization of Ultra-Thin Laser Targets for the Acceleration of Protons and Ions at the DRACO Laser with Ultra-High Pulse Contrast — •Alexander Jahn^{1, 2}, Joshua Gössel^{1, 2}, Stephan Kraft¹, Lieselotte Obst^{1, 2}, Hans-Peter Schlenvoigt¹, Karl Zeil¹, and Ulrich Schramm^{1, 2} — ¹HZDR, Dresden, Germany — ²Technische Universität Dresden, Dresden, Germany

High-intensity laser-plasma ion generation is promising as a compact, low-cost proton source for applications like ion beam therapy. To reach the performance of conventional and already existing systems there is still a lot to optimize. One way to characterize the ion acceleration performance for given laser parameters can be performed using thickness scans and hence the determination of the optical target thickness. We present the development of an ultra-thin foil target system (range of 10--1000 nm) including reliable thickness measurement. These targets will be applied for measurements at 600 TW Draco laser at the HZDR with ultra-high contrast. The foils are made of formvar (aka polyvinyl formal) or polysterene powder which has to be solved and put on a water surface to generate a thin film structure. To measure the thickness of the produced targets a F20 reflectometry system by Filmetrics is established. The reflectometer calculates the thickness of the measured sample out of the reflection spectrum based on the phenomenon of thin-film interference. The main advantage of this technique is the possibility to characterize the target thickness directly before the high power laser shot at the interaction point in the vacuum chamber.