The Offline 2 facility at ISOLDE, CERN

Offline 2 is the most recent mass separator beamline at the Isotope Separator On-line DEvice (ISOLDE) infrastructure, dedicated for developments of ion beam production and manipulations. It is a non-radioactive laboratory which has been constructed to mimic the ion beam production and ion beam delivery at the on-line facility at ISOLDE. Here, positive or negative ion beams with kinetic energies of up to 60 keV can be produced and extracted. One of the main features of the Offline 2 beamline is a dedicated Radio-Frequency Quadrupole cooler and buncher (RFQcb) which allows to deliver both continuous ion beams as well as bunched beams. This RFQcb installation serves as a development platform for its twin installation, the ISOLDE cooler (ISCOOL), which is in operation at the ISOLDE on-line facility. To complete the installation, a dedicated laser laboratory has been constructed in an adjacent room to the mass separator with an optical path towards the ion source through a window in the separator magnet. This enables the use and further development of the Resonance Ionization Laser Ion Source (RILIS) towards better beam purification and higher spectral resolution for in-source laser spectroscopy. This new facility will be used for ion source developments, beam optics and beam manipulation studies aiming to improve ion beam quality and the performance of target-ion sources during on-line operation at the ISOLDE facility. In this report, the design and features of the facility are described.