Energy-spread compensation in a solenoid-based secondary radioactive beam apparatus

Methods for reducing the energy spread in low-energy short-lived secondary radioactive nuclear beams produced in a solenoid-based system are examined. In particular, the use of a tapered energy-loss absorber placed off-focus is studied and a first set of in-beam tests reported. In addition, realistic ion-optical ray-tracing time-of-flight calculations for energy-spread compensation are presented for both short-(3 m) and long-(6 m) flight path options. The advantages and disadvantages of the various techniques are discussed.