Atomic Physics at the 5 MV Tandem at Demokritos: the UoC APAPES project

Abstract

University of Crete (UoC) has initiated the research initiative APAPES funded by THALES‡ that has already set up a new experimental station with a beam line dedicated solely on basic atomic physics research. This new experiment utilizing Zero-degree Auger Projectile Spectroscopy (ΖΑPS) is located at the 5 MV TANDEM accelerator of the National Center for Scientific Research (NCSR) “Demokritos” in Athens, and has been put together to perform high resolution studies of electrons emitted during ion-atom collisions. The apparatus consists of a Hemispherical Deflector Analyzer (HDA) combined with a 2-dimensional Position Sensitive Detector (PSD) and a doubly-differentially pumped gas cell containing the gas-target. The goal is to perform a systematic isoelectronic investigation of K-Auger spectra emitted from pre-excited and ground state He-like ions in collisions with gas targets using novel techniques. So far, various Auger electron spectra produced through collisions of mixed state (1s2, 1s2s3S) C4+ ion beam with various gas targets have been recorded. In addition, detailed simulations using SIMION have also explored the optimal lens voltages and the solid angle correction factors for long-lived metastable states. A terminal gas stripper system is scheduled to be installed in the accelerator, extending its range of available charge states and enabling the production of pure ground state as well as mixed state beams with different metastable fractions, a measurement vital to APAPES. Here, we report on the progress made up to date on the APAPES project, the description of the apparatus, updated results and plans for the near future.