Optimization of evaporation parameters and fabrication of natural Si target for in-beam gamma ray spectroscopy

The natural Si is hard, brittle crystalline solid with a blue-gray metallic luster. It is composed of three stable isotopes ²⁸Si, ²⁹Si and ³⁰Si having abundance 92.2%, 4.7% and 3.1%, respectively. The primary goal of our experiment is to perform gamma-ray spectroscopy in the mass region A∼40, which is astrophysical important towards the endpoint of nova nucleosynthesis. For this, ¹²C beam is going to be used on ²⁸Si target to populate nuclei by fusion evaporation reaction. As per reaction's optimized yield calculations, ²⁸Si target of thickness ∼400–900 µg/cm² on Gold (Au) backing of thickness 6-7 mg/cm² has been proposed. As natural Si is cost-effective hence can be used for target fabrication trials to optimize evaporation parameters. Also, because of higher abundance of ²⁸Si in Si, later can be used as back-up target. The Si targets were prepared successfully using rolling machine and electron beam coating unit with high vacuum environment and the final experiment will be carried out with Indian National Gamma Array (INGA) and Charge Particle Detector Array (CPDA) setup at IUAC, New Delhi