Field-map and Beam Transport Calculations of the Magnetic Separator at ALTO Facility at Orsay

The Institute of Nuclear Physics at Orsay (IPNO) has always been a major player in building accelerators for nuclear physics. The Accelerator Linear Tandem Orsay (ALTO) facility is powered by a 50 MeV/10uA linear electron accelerator dedicated to the production of radioactive beams [1]. The production mode is based on the photo-fission process of a thick UCx target heated up to 2000°C and using the Isotopes Separation On-Line (ISOL) technique [2]. For the ionization of the released fission fragments, three ion source types can be coupled to the target: a Febiad ion source, surface ion source, and laser ion source. The facility can deliver the radioactive ions beams (RIB) to six different experimental setups. The mass of the produced mono-charged Radioactive Ions Beam is selected using a magnetic dipole in order to select a nucleus before its transmission through electrostatic devices up to the experimental setups [3]. This paper is focused on the separator that was built and exploited with success since 43 years. The separator is located closely to the exit of the source of RIB production. We propose to revisit this dipole with a precise field-map calculation and particles transport simulations. These results will be used as a first brick for the understanding and reliability of the transmission along the RIB lines at the ALTO facility.