Design of a large stopping gas cell for

Design of a large stopping gas cell for IGISOL In the ion guide technique, reaction products are stopped in helium as ions and transported as ions to further analysis. Target At the IGISOL in JYFL, the ions are transported with the gas flow alone. This limits the size of gas cell: bigger gas cell is not better, since the ion survival time is limited. Stopping efficiency for the fission products is ≈ 0. 75 %, and their mean extraction time is ≈ 100 ms. In demand: • • Extractor SPIG electrode higher stopping efficiency faster extraction. Possible solution: large stopping gas cell with electric field guidance In this task, • • The capability of the means of faster ion extraction will be studied utilising simulations The site specific constraint at IGISOL (space, radiation, high voltage) will be surveyed Suitable means for IGISOL will be adopted Detailed technical drawings will be produced Beam

Design of a large stopping gas cell for IGISOL Examples of large gas cells with electric field guidance GSI cryogenic gas cell NIMA 770 (2015) 87 Electric field guidance is based on combination of static drifting field, RF field preventing ions colliding on walls, and gas flow near the exit. ACGS (Advanced Cryogenic Gas Stopper) at NSCL NIMB 463 (2020) 378 GSI futuristic gas cell NIMB 376, (2016) 216 ANL CARIBU NIMB 376, (2016) 246

Design of a large stopping gas cell for IGISOL-4 facility area at JYFL

Design of a large stopping gas cell for IGISOL NIMB 397, (2016) 1 Constraints • • • Operated in high voltage Should be fitted in the current space without major revisions Should be removable: fission/MNT are not only reactions used Is cryogenity unavoidable? Should tolerate high radiation levels (neutron induced fission) Progress • • Possible technical solutions have been reviewed and evaluated Decision of the line of the development has not been made Simulations have not been started; MS dead line will not be met. Expected delay 12 months