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RESEARCH PRODUCT

Studying exotic nuclides close to the N = Z line at the HIGISOL facility

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The ion guide [1, 2] for heavy-ion fusion-evaporation reactions (HIGISOL) which was developed by Beraud et al. [3] has been implemented at the IGISOL facility in Jyvaskyla [4]. This system was modified over the past 5 years. Figure 1 shows the present set-up. The HIGISOL takes advantage of the different angular distributions of primary beam and reaction products: the primary beam is stopped in front of the stopping chamber and the reaction products enter the stopping chamber through a thin foil passing the beam stop. This so called “shadow” method removes the plasma effect since the primary beam is not ionising the stopping gas. In order to improve ion optical properties, mainly to reduce the energy spread, the normal skimmer system was replaced by a sextupole ion guide, SPIG. The mass resolving power (MRP) for a 219Rn ion beam was measured to be 1100, independent of the helium pressure and SPIG DC voltage level relative to the stopping chamber [6]. The MRP measured earlier with the skimmer was 250 for 219Xe [4].