The performance of the cryogenic buffer-gas stopping cell of SHIPTRAP

[摘要] Direct high-precision mass spectrometry of the heaviest elements with SHIPTRAP, at GSI in Darmstadt, Germany, requires high efficiency to deal with the low production rates of such exotic nuclides. A second-generation gas stopping cell, operating at cryogenic temperatures, was developed and recently integrated into the relocated system to boost the overall efficiency. Offline measurements using Ra-223 and (225)AC recoil-ion sources placed inside the gas volume were performed to characterize the gas stopping cell with respect to purity and extraction efficiency. In addition, a first online test using the fusion-evaporation residue No-254 was performed, resulting in a combined stopping and extraction efficiency of 33(5)%. An extraction time of 55(44)ms was achieved. The overall efficiency of SHIPTRAP for fusion-evaporation reaction products was increased by an order of magnitude to 6(1)%. This will pave the way for direct mass spectrometry of heavier and more exotic nuclei, eventually in the region of superheavy elements with proton numbers Z >= 104.

[发布日期] 2020-01-15

[效力级别]  Proceedings Paper

[关键词] Cryogenic gas stopping cell;Stopping and extraction efficiency;Extraction time;Penning traps;Mass spectrometry;Fusion-evaporation reaction products;Transfermlum elements nobelium