Experimental study of ECR plasmas in stationary versus turbulent regimes for in-plasma β -decay investigations

A new experimental study of electron cyclotron resonance (ECR) plasmas in stationary versus turbulent regimes was recently carried out in the framework of the PANDORA (plasmas for astrophysics, nuclear decays observation and radiation for archaeometry) project, which aims to measure ss-decays of nuclear astrophysical interest for the first time in laboratory plasmas emulating some stellar-like conditions. The experimental study was finalized to correlate the nuclear activity to the thermodynamic conditions of the plasma environment by means of a multi-diagnostic approach. Advanced analysis methods and non-invasive tools were properly developed, including high-resolution space-resolved X-ray spectroscopy and imaging, which allow unprecedented investigations of thermodynamic plasma properties as well as of plasma structure, confinement and dynamics of losses. Furthermore, an innovative plasma heating mode (two-close-frequency heating) has been investigated, showing to be a powerful method for improving the plasma stability, damping instabilities. In order to correlate plasma properties to nuclear activity, GEANT4 simulations devoted to design a gamma-ray detector array to tag the in-plasma ss-decays by detecting gamma-rays emitted by daughters nuclei were carried out. The sensitivity of the PANDORA setup was specifically investigated in a virtual experiment, for the first PANDORA physics cases: Cs-134, Lu-176, Nb-94. The obtained results allowed to demonstrate that laboratory ECR plasmas in compact traps are suitable and interesting environments for fundamental studies as well as for applications.