Off-axis electron injection into a cooler Penning trap


The TITAN facility at TRIUMF is a series of ion traps designed for precision mass spectrometry on rare isotopes. The combination of an on-line electron beam ion trap charge breeder with a Penning trap enables measurements with radioactive ions in high charge states. The use of highly charged ions (HCI) can yield a significant gain in mass precision and mass resolving power. However, the benefits of high charge states are mitigated since the charge breeding deteriorates the beam quality. To achieve suitable beam properties and access the full potential of Penning trap mass spectrometry with HCI a cooler Penning trap (CPET) for electron cooling of highly charged radioisotopes is being developed. In this device short-lived HCI will be sympathetically cooled by a co-trapped electron plasma prior to mass measurement. For electron plasma generation electrons are injected from an off-axis electron gun placed in the fringe field of CPET’s solenoid magnet. We report on the development of an electron gun design that is adapted to the operation in lateral magnetic fields and has enabled efficient and robust electron plasma formation in CPET.

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TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada (NRC). This work was partially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI). We would like to thank O. Kester for his continuous support during the simulation stage and for his valuable input on the design of the improved electron gun. We thank TRIUMF’s technical staff, especially M. Good, for the mechanical realization of the electron guns discussed in this article. We further acknowledge helpful advice from K. Blaum.

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Correspondence to S. F. Paul.

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This article is part of the Topical Collection on Proceedings of the 7th International Conference on Trapped Charged Particles and Fundamental Physics (TCP 2018), Traverse City, Michigan, USA, 30 September-5 October 2018

Edited by Ryan Ringle, Stefan Schwarz, Alain Lapierre, Oscar Naviliat-Cuncic, Jaideep Singh and Georg Bollen

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Paul, S.F., Kootte, B., Lascar, D. et al. Off-axis electron injection into a cooler Penning trap. Hyperfine Interact 240, 50 (2019).

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  • Electron cooling
  • Highly charged ions
  • Electron guns
  • Penning traps