Abstract
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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References
Gumberidze, A., et al.: Quantum electrodynamics in strong electric fields: the ground-state lamb shift in hydrogenlike uranium. Phys. Rev. Lett. 94, 223001 (2005)
Ullmann, J., et al.: High precision hyperfine measurements in bismuth challenge bound-state strong-field QED. Nat. Commun. 8, 15484 (2017)
Werth, G., et al.: Highly charged ions, quantum-electrodynamics, and the electron mass. Int. J. Mass Spectrom. 251, 152–158 (2006)
Blaum, K., Herfurth, F.: Trapped Charged Particles and Fundamental Interactions, vol. 749, p 130. Springer, Heidelberg (2008)
Bergström, I.: SMILETRAP - A penning trap facility for precision mass measurements using highly charged ions. Nucl. Instrum. Methods Phys. Res., Sect. A 487, 3 (2002)
Sturm, S., et al.: High-precision measurement of the atomic mass of the electron. Nature 506, 7489 (2014)
Heiße, F., et al.: High-precision measurement of the proton’s atomic mass. Phys. Rev. Lett. 119, 033001 (2017)
Repp, J., et al.: PENTATRAP: A novel cryogenic multi-penning-trap experiment for high-precision mass measurements on highly charged ions. Appl. Phys. B 107, 4 (2012)
Kwiatkowski, A.A., et al.: Precision mass measurements at TITAN with radioactive ions. Nucl. Instrum. Methods Phys. Res., Sect. B 317, 517–521 (2013)
Ettenauer, S., et al.: First use of high charge states for mass measurements of short-lived nuclides in a penning trap. Phys. Rev. Lett. 107, 12 (2011)
Frekers, D., et al.: Penning-trap Q-value determination of the Ga71(ν,e−)Ge71 reaction using threshold charge breeding of on-line produced isotopes. Phys. Lett. B 722, 4 (2013)
Gallant, A.T., et al.: Highly charged ions in penning traps: a new tool for resolving low-lying isomeric states. Phys. Rev. C 85, 4 (2012)
Ettenauer, S., et al.: Advances in precision, resolution, and separation techniques with radioactive, highly charged ions for penning trap mass measurements. Int. J. Mass Spectrom. 349, 74–80 (2013)
Kellerbauer, A., et al.: Buffer gas cooling of ion beams. Nucl. Instrum. Methods Phys. Res., Sect. A 469, 2 (2001)
Rolston, S.L., Gabrielse, G.: Cooling antiprotons in an ion trap. Hyperfine Interact. 44, 1 (1989)
Bernard, J., et al.: Electron and positron cooling of highly charged ions in a cooler penning trap. Nucl. Instrum. Methods Phys. Res., Sect. A 532(1-2), 224–228 (2004)
Ke, K., et al.: A cooler ion trap for the TITAN on-line trapping facility at TRIUMF. Hyperfine Interact. 173(1), 103–111 (2006)
Herfurth, F., et al.: Highly charged ion s at rest: the HITRAP project at GSI. AIP Conf. Proc. 793(1), 278–292 (2005)
Simon, V.V., et al.: Cooling of short-lived, radioactive, highly charged ions with the TITAN cooler penning trap. Hyperfine Interact. 199(1), 151–159 (2011)
Lapierre, A., et al.: Nucl. Instrum. Methods Phys. Res., Sect. A 624(1), 54–64 (2010)
Brodeur, M.: First Direct Mass Measurement of the Two and Four Neutron Halos 6He and 8He Using the TITAN Penning Trap Mass Spectrometer, PhD thesis, University of British Columbia (2010)
Ball, G.C., Hackman, G., Krücken, R.: The TRIUMF-ISAC facility: two decades of discovery with rare isotope beams. Phys. Scr. 91(9), 093002 (2016)
Malmberg, J.H., Driscoll, C.F.: Long-time containment of a pure electron plasma. Phys. Rev. Lett. 44, 654–657 (1980)
Simon, V.V.: Penning-Trap Mass Spectrometry of Radioactive, Highly Charged Ions: Measurements of Neutron-Rich Rb and Sr Nuclides for Nuclear Astrophysics and the Development of a Novel Penning Trap for Cooling Highly Charged Ions, PhD thesis, Ruprecht-Karls-Universität Heidelberg (2012)
Paul, S.F.: Off-Axis Electron Injection into a Cooler Penning Trap, Master’s thesis, Ruprecht-Karls-Universität Heidelberg (2017)
Li, G.Z., Guan, S., Marshall, A.G.: Sympathetic cooling of trapped negative ions by self-cooled electrons in a fourier transform ion cyclotron resonance mass spectrometer. J. Am. Soc. Mass Spectrom. 8(8), 793–800 (1997)
Kootte, B., et al.: Quantification of the Electron Plasma in TITAN’S Cooler Penning Trap. Int. Workshop on Beam Cooling and Related Topics (COOL’15), pp 39–42. JACOW, Geneva (2016)
Mohamed, T., et al.: Fast electron accumulation and its mechanism in a harmonic trap under ultrahigh vacuum conditions. Phys. Plasmas 18(3), 032507 (2011)
Chowdhury, U.: A Cooler Penning Trap to Cool Highly Charged Radioactive Ions and Mass Measurement of 24 Al, PhD thesis, University of Manitoba (2016)
Tungsten filament cathode specifications, Kimball Physics Online Resource, https://www.kimballphysics.com/cathode-specs-w. Accessed 4 March 2019
Ringle, R.: Int. J. Mass Spectrom. 263(1), 38–44 (2007)
Lascar, D., et al.: Nucl. Instrum. Methods Phys. Res., Sect. A 868(1), 133–138 (2017)
Herrmannsfeldt, W.B.: EGUN - An electron optics and gun design program. SLAC-Report-331 (1988)
Dahl, D.A.: SIMION for the personal computer in reflection. Int. J. Mass Spectrom. 200(1), 3–25 (2000)
Herring, C., Nichols, M.H.: Thermionic emission. Rev. Mod. Phys. 21, 185–270 (1949)
SIMION’s simplex optimizer: Online resource, http://simion.com/info/lua_simionx.SimplexOptimizer.html. Accessed 22 February 2019
Umstattd, R.J.: A simple physical derivation of child–langmuir space-charge-limited emission using vacuum capacitance. Am. J. Phys. 73(2), 160–163 (2005)
Acknowledgements
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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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). https://doi.org/10.1007/s10751-019-1587-6
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DOI: https://doi.org/10.1007/s10751-019-1587-6