| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1683718 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2007 | 6 Pages |
The extraction efficiency and extraction time of the SHIPTRAP gas-filled stopping cell were measured and chemical processes occurring during extraction of the stopped ions were investigated. The measurements were performed using 219Rn recoil ions from the α-decay of a calibrated point-like 223Ra ion source. The extraction time was measured to be shorter than 10 ms at a helium gas pressure in the gas cell of 40 mbar. Thus, nuclides with half-lives on the order of a few milliseconds are accessible for the various precision experiments planned at SHIPTRAP. Extraction efficiencies of up to 30% were obtained at a helium pressure of 50 mbar. The estimated total efficiency of the gas cell, derived from the product of calculated stopping and measured extraction efficiency, amounts to about 10%. Factors limiting the efficiency are quantitatively understood. Under standard operating conditions, ion–molecule reactions in the gas cell do not seem to limit the efficiency of the gas cell significantly.
