Advertisement

A VUV detection system for the direct photonic identification of the first excited isomeric state of 229Th

  • Benedict Seiferle
  • Lars von der Wense
  • Mustapha Laatiaoui
  • Peter G. Thirolf
Regular Article

Abstract

With an expected energy of 7.6(5) eV, 229Th possesses the lowest excited nuclear state in the landscape of all presently known nuclei. The energy corresponds to a wavelength of about 160 nm and would conceptually allow for an optical laser excitation of a nuclear transition. We report on a VUV optical detection system that was designed for the direct detection of the isomeric ground-state transition of 229Th. 229(m)Th ions originating from a 233U α-recoil source are collected on a micro electrode that is placed in the focus of an annular parabolic mirror. The latter is used to parallelize the UV fluorescence that may emerge from the isomeric ground-state transition of 229Th. The parallelized light is then focused by a second annular parabolic mirror onto a CsI-coated position-sensitive MCP detector behind the mirror exit. To achieve a high signal-to-background ratio, a small spot size on the MCP detector needs to be achieved. Besides extensive ray-tracing simulations of the optical setup, we present a procedure for its alignment, as well as test measurements using a D2 lamp, where a focal-spot size of ≈100 μm has been achieved. Assuming a purely photonic decay, a signal-to-background ratio of ≈7000:1 could be achieved.

Graphical abstract

Keywords

Optical Phenomena and Photonics 

References

  1. 1.
    L.A. Kroger, C.W. Reich, Nucl. Phys. A 259, 29 (1976)ADSCrossRefGoogle Scholar
  2. 2.
    C.W. Reich, R.G. Helmer, Phys. Rev. Lett. 64, 271 (1990)ADSCrossRefGoogle Scholar
  3. 3.
    C.W. Reich, R.G. Helmer, Phys. Rev. C 49, 1845 (1994)ADSCrossRefGoogle Scholar
  4. 4.
    B.R. Beck et al., Phys. Rev. Lett. 98, 142501 (2007)ADSCrossRefGoogle Scholar
  5. 5.
    B.R. Beck et al., Proc. of the 12th Int. Conf. on Nucl. Reaction Mechanisms, Varenna, 2009, edited by F. Cerutti, A. Ferrari, LLNL-PROC-415170 (2009)Google Scholar
  6. 6.
    G.M. Irwin, K.H. Kim, Phys. Rev. Lett. 79, 6 (1997)CrossRefGoogle Scholar
  7. 7.
    D.S. Richardson et al., Phys. Rev. Lett. 80, 15 (1998)Google Scholar
  8. 8.
    S.B. Utter et al., Phys. Rev. Lett. 82, 3 (1999)CrossRefGoogle Scholar
  9. 9.
    R.W. Shaw et al., Phys. Rev. Lett. 82, 6 (1999)CrossRefGoogle Scholar
  10. 10.
    E. Browne et al., Phys. Rev. C 64, 014311 (2001)ADSCrossRefGoogle Scholar
  11. 11.
    Barci et al., Phys. Rev. C 64, 034329 (2003)ADSCrossRefGoogle Scholar
  12. 12.
    T. Mitsugashira et al., J. Radioanal. Nucl. Ch. 255, 63 (2003)CrossRefGoogle Scholar
  13. 13.
    H. Kikunaga et al., Radiochim. Acta 93, 507 (2005)CrossRefGoogle Scholar
  14. 14.
    I. D. Moore et al., Argonne National Laboratory Physics Division Report, PHY-10990-ME-2004 (2004)Google Scholar
  15. 15.
    Z.O. Guimaraes, O. Helene, Phys. Rev. C 71, 044303 (2005)ADSCrossRefGoogle Scholar
  16. 16.
    Y. Kasamatsu et al., Research Report of Laboratory of Nuclear Science, Tohuko University, 38, 32 (2005)Google Scholar
  17. 17.
    K. Zimmermann, Ph.D. thesis, University Hannover, Germany, 2010Google Scholar
  18. 18.
    E.L. Swanberg, Ph.D. thesis, University of California, Berkeley, 2012Google Scholar
  19. 19.
    X. Zhao et al., Phys. Rev. Lett. 109, 160801 (2012)ADSCrossRefGoogle Scholar
  20. 20.
    E. Peik et al., Phys. Rev. Lett. 111, 018901 (2013)ADSCrossRefGoogle Scholar
  21. 21.
    E. Ruchowska et al., Phys. Rev. C 73, 044326 (2006)ADSCrossRefGoogle Scholar
  22. 22.
    E. Peik, Ch. Tamm, Europhys. Lett. 61, 181 (2003)ADSCrossRefGoogle Scholar
  23. 23.
    G.A. Kazakov et al., New J. Phys. 14, 083019 (2012)ADSCrossRefGoogle Scholar
  24. 24.
    C.J. Campbell et al., Phys. Rev. Lett. 108, 120802 (2012)ADSCrossRefGoogle Scholar
  25. 25.
    E. Litvinova et al., Phys. Rev. C 79, 064303 (2009)ADSCrossRefGoogle Scholar
  26. 26.
    V.V. Flambaum et al., Europhys. Lett. 85, 50005 (2009)ADSCrossRefGoogle Scholar
  27. 27.
    V.V. Flambaum, Phys. Rev. Lett. 97, 092502 (2006)ADSCrossRefGoogle Scholar
  28. 28.
    T. Rosenbund et al., Science 319, 1808 (2008)ADSCrossRefGoogle Scholar
  29. 29.
    E.V. Tkalya, Phys. Rev. Lett. 106, 162501 (2011)ADSCrossRefGoogle Scholar
  30. 30.
    V. Barci et al., Phys. Rev. C 68, 034329 (2003)ADSCrossRefGoogle Scholar
  31. 31.
    E. Haettner, Ph.D. thesis, University Giessen, Germany, 2011Google Scholar
  32. 32.
    L.v.d. Wense et al., Eur. Phys. J. A 51, 29 (2015)ADSCrossRefGoogle Scholar
  33. 33.
    F.F. Karpeshin et al., Phys. Rev. C 76, 054313 (2007)ADSCrossRefGoogle Scholar
  34. 34.
    W.F. Meggers et al., Natl. Bur. Stand. (U.S.), Monogr. 145 (1975)Google Scholar
  35. 35.
    R. Steinkopf et al., Proc. of SPIE, edited by A. Duparré, R. Geyl (SPIE, Bellingham, WA, 2008), Vol. 7102Google Scholar
  36. 36.
    P. Maier-Komor et al., Nucl. Instrum. Meth. A 480, 65 (2002)ADSCrossRefGoogle Scholar
  37. 37.
    L.v.d. Wense et al., J. Instrum. 8, P03005 (2013)CrossRefGoogle Scholar
  38. 38.
    D.A. Dahl, Int. J. Mass spectrom. 200, 3 (2000)ADSCrossRefGoogle Scholar

Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Benedict Seiferle
    • 1
  • Lars von der Wense
    • 1
  • Mustapha Laatiaoui
    • 2
    • 3
  • Peter G. Thirolf
    • 1
  1. 1.Ludwig-Maximilians-Universität MünchenGarchingGermany
  2. 2.GSI Helmholtzzentrum für Schwerionenforschung GmbHDarmstadtGermany
  3. 3.Helmholtz Institut MainzMainzGermany

Personalised recommendations