Fabrication of thin carbon-backed target of 185Re by evaporation technique and self supporting target of 170Er by cold rolling technique for the study of nuclear reaction dynamics

Abstract

Thin, durable and uniform self-supporting isotopic targets of ¹⁷⁰Er and ¹⁸⁵Re targets with carbon backing have been fabricated by using cold-rolling and high vacuum evaporative deposition techniques respectively at Inter University Accelerator Centre (IUAC) target laboratory, New Delhi. For the fabrication of ¹⁸⁵Re, e-Gun (electron-Gun) evaporation technique was used. The thickness obtained for ¹⁷⁰Er was around 2.1 mg/cm² and for ¹⁸⁵Re, it was 200 $\mu$g/cm² with a carbon backing of 50 $\mu$g/cm². Using characterization techniques such as energy dispersive X-ray spectroscopy (EDX), Rutherford backscattering spectroscopy (RBS), $\alpha$ energy loss technique, and X-ray diffraction, the thickness and elemental composition of the targets were analyzed. These measurements essentially exhibited no contamination, indicating their excellent purity and durability. Both the targets were used in nuclear experiment performed at NAND (National Array of Neutron Detectors) facility, IUAC, New Delhi to study the nuclear reaction dynamics. For such kind of study, one needs pure targets without any contamination to ensure that the neutron data is coming only from the reaction of interest. For mass distribution measurements, thin target (100–200 $\mu$g/cm²) is the requirement.