Experimental emittance measurements with an Allison scanner for characterisation of an ISOL based target-ion source system at ALTO-LEB

Studies performed at the ALTO-LEB research platform at IJCLab (Orsay, France) are presented. These investigations are primarily dedicated to the first emittance measurements ever carried out at the facility, with the objective of providing the initial characterisation of the 30 keV stable ion beam delivered by the ALTO-LEB target-ion source. The platform is first described in connection with the experimental objectives, with particular emphasis on the target–ion source and the beam transport lines developed over the past two decades. The main parameters of the emittance measurements performed using an Allison-type scanner are detailed, together with the available beam diagnostics and optical elements. The emittance analysis results are presented. The absolute transverse emittances, measured with the Allison-type scanner at ALTO-LEB, yield ϵ r m s x = 2 . 2 ± 0 . 2 π .mm.mrad and ϵ r m s y = 1 . 6 ± 0 . 1 π .mm.mrad. The robustness of these results is evaluated through beam transport simulations compared with beam profile measurements obtained along the beam lines. Finally, a preliminary characterisation of the beam properties at the target-ion source is attempted using a back-tracing method.