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To precisely measure atomic masses and select neutron-deficient isotopes produced by fusion evaporation reactions, an MRTOF-MS (multi-reflection time-of-flight mass spectrometer) at the SHANS (Spectrometer for Heavy Atom and Nuclear Structure) is being developed. One of the key parts, an RF ion trap system with the aim to provide brilliant ion pulses with a low energy spread and narrow pulse width for ion preparation prior to injection into the MRTOF mass analyzer, has been constructed and commissioned offline successfully. The principle, construction details and test results are reported. Pulsed beams of 39K1+, 85,87Rb1+ and 133Cs1+ ions have been tested and the amplitudes and frequencies of the RF signals, DC voltages, helium gas pressure and time parameters have been scanned. The corresponding time spreads have reached 0.252 µs, 0.394 µs and 0.450 µs, respectively.

With the recent commissioning of a gas-filled recoil separator at Institute of Modern Physics (IMP) in Lanzhou, the decay properties of 271Ds (Z = 110) were studied via the 208Pb(64Ni, n) reaction at a beam energy of 313.3MeV. Based on the separator coupled with a position sensitive silicon strip detector, we carried out the energy-position-time correlation measurements for the implanted nucleus and its subsequent decay ??'s. One ??- decay chain for 271Ds was established. The α energy and decay time of the 271Ds nucleus were measured to be 10.644MeV and 96.8 ms, which are consistent with the values reported in the literature. [ABSTRACT FROM AUTHOR]