Evaporation residue collection efficiencies and position spectra of the Dubna gas-filled recoil separator

The focal-plane position spectra and collection efficiencies of the Dubna gas-filled recoil separator at the U400 cyclotron used to separate evaporation residues of complete fusion reaction products are described. The separator consists of a 23 deg. -dipole magnet and a quadrupole doublet and is filled with hydrogen at a pressure of about 1 Torr. After passing through the time-of-flight system, the separated evaporation residues are collected in a 120 mm·40 mm position-sensitive semiconductor detector at the focal plane. Depending on the asymmetry of the projectile, target combinations, the measured collection efficiencies were 3-45%, with suppression factors exceeding 1015 and 104 for beam and target-like particles, respectively. The ANAMARI code that is used to determine the separator settings is described and its predictions for the evaporation residue position spectra and collection efficiencies are compared with experimental data