학술논문
Doppler and sympathetic cooling for the investigation of short-lived radioactive ions
Document Type
Author
Sels, S.; Maier, F. M.; Au, M.; Fischer, P.; Kanitz, C.; Lagaki, V.; Lechner, S.; Leistenschneider, E.; Leimbach, David, 1992; Lykiardopoulou, E. M.; Kwiatkowski, A. A.; Manovitz, T.; Vila Gracia, Y. N.; Neyens, G.; Plattner, P.; Rothe, S.; Schweikhard, L.; Vilen, M.; Wolf, R. N.; Malbrunot-Ettenauer, S.
Source
Physical Review Research. 4(3)
Subject
Language
English
ISSN
2643-1564
Abstract
At radioactive ion beam (RIB) facilities, ions of short-lived radionuclides are cooled and bunched in buffer-gas-filled Paul traps to improve the ion-beam quality for subsequent experiments. To deliver even colder ions, beneficial to RIB experiments' sensitivity or accuracy, we employ Doppler and sympathetic cooling in a Paul trap cooler-buncher. The improved emittance of Mg+, K+, and O2+ ion beams is demonstrated by a reduced time-of-flight spread of the extracted ion bunches with respect to room-temperature buffer-gas cooling. Cooling externally-produced hot ions with energies of at least 7 eV down to a few Kelvin is achieved in a timescale of O(100 ms) by combining a low-pressure helium background gas with laser cooling. This is sufficiently short to cool short-lived radioactive ions. As an example of this technique's use for RIB research, the mass-resolving power in a multireflection time-of-flight mass spectrometer is shown to increase by up to a factor of 4.6 with respect to buffer-gas cooling. Simulations show good agreement with the experimental results and guide further improvements and applications. These results open a path to a significant emittance improvement and, thus, unprecedented ion-beam qualities at RIB facilities, achievable with standard equipment readily available. The same method provides opportunities for future high-precision experiments with radioactive cold trapped ions.