The TRIple PLunger for EXotic beams TRIPLEX for excited-state lifetime measurement studies on rare isotopes

A new device, the TRIple PLunger for EXotic beams (TRIPLEX), has been developed for lifetime measurement studies with rare isotope beams. This plunger device holds up to three metal foils in the beam path and facilitates the recoil distance Doppler-shift technique to measure lifetimes of nuclear excited states in the range of 1 ps to 1 ns. The unique design allows independent movement of the target and the second degrader with respect to a fixed first degrader in between, enabling advanced experimental approaches, such as the differential recoil distance method and the double recoil distance method. The design and control of the device are presented in this paper, together with simulated performances of the new applications. As an example of actual experiments, results from the lifetime measurement of the neutron-rich 17C isotope performed at the National Superconducting Cyclotron Laboratory are shown.