HYRA gas-filled separator coupled to 4π spin spectrometer at IUAC, New Delhi

The Hybrid Recoil mass Analyzer (HYRA) operated in gas-filled mode has recently been coupled with the TIFR 4π spin spectrometer at IUAC, New Delhi to carry out spin (or angular momentum) distribution of heavy residues from fusion-evaporation reactions and spin gated GDR measurements. The details of the combined facility, initial experiments on evaporation residue (ER) tagged γ-multiplicity and the extraction of average transmission efficiency of HYRA are presented. Initial experimental results are encouraging with negligible background at the focal plane. Comparison of 3 entrance channels leading to the same compound nucleus 200Pb*, at similar excitation energies, reveal that for more symmetric system (studied with the facility elaborated here) the reduction in the normalized ER cross-section, at higher excitation energies, is accompanied by a reduction in average angular momentum. Though the symmetric combination brings in a lot more angular momentum in the entrance channel, effective angular momentum transferred to surviving ERs is smaller