The STELLA Apparatus for Particle-Gamma Coincidence Fusion Measurements with Nanosecond Timing

TL;DR

The STELLA apparatus enables precise measurement of extremely low cross-section heavy-ion fusion reactions at sub-barrier energies using advanced coincidence detection and nanosecond timing techniques.

Contribution

This work introduces the STELLA experimental station with innovative features like a rotating target and nanosecond timing for improved sub-barrier fusion measurements.

Findings

Achieved detection of fusion cross sections as low as tens of picobarn.

Demonstrated effective separation of proton and alpha particles using nanosecond timing.

Enabled high beam intensities with a rotating target mechanism.

Abstract

The STELLA (STELlar LAboratory) experimental station for the measurement of deep sub-barrier light heavy-ion fusion cross sections has been installed at the Androm\`{e}de accelerator at the Institut de Physique Nucl\'{e}aire, Orsay (France). The setup is designed for the direct experimental determination of heavy-ion fusion cross sections as low as tens of picobarn. The detection concept is based on the coincident measurement of emitted gamma rays with the UK FATIMA (FAst TIMing Array) and evaporated charged particles using a silicon detector array. Key developments relevant to reaching the extreme sub-barrier fusion region are a rotating target mechanism to sustain beam intensities above 10$\mu$A, an ultra-high vacuum to prevent carbon built-up and gamma charged-particle timing in the order of nanoseconds sufficient to separate proton and alpha particles.