X-ray Spectroscopy of Muonic Atoms Isolated in Vacuum with Transition Edge Sensors


High-resolution X-ray spectroscopy of the highly charged muonic atoms/ions isolated in vacuum is an ideal probe to explore quantum electrodynamics under extremely strong electric fields, which is one of the major topic in fundamental atomic physics. A feasibility test measurement with a low-density neon gas target was performed by observing X-rays emitted by muonic neon via the \(5 \rightarrow 4\) transition, \(\sim\) 6.3 keV, using a multi-pixel array of superconducting transition-edge-sensor (TES) microcalorimeters at the J-PARC muon facility. We successfully demonstrated the feasibility of muonic atom X-ray spectroscopy with a gas target at a pressure as low as 0.1 atom using TES array under an intense pulsed muon beam.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3


  1. 1.

    F. Sauter, Z. Phys. 69, 742 (1931)

    ADS  Article  Google Scholar 

  2. 2.

    F. Sauter, Z. Phys. 73, 547 (1931)

    ADS  Article  Google Scholar 

  3. 3.

    W. Heisenberg, H. Euler, Z. Phys. 98, 714 (1936)

    ADS  Article  Google Scholar 

  4. 4.

    J. Schwinger, Phys. Rev. 82, 664 (1951)

    ADS  MathSciNet  Article  Google Scholar 

  5. 5.

    E. Borie, G.A. Rinker, Rev. Mod. Phys. 54(1), 67–118 (1982)

    ADS  Article  Google Scholar 

  6. 6.

    W. Higemoto et al., Quantum Beam Sci. 1(1), 11 (2017)

    ADS  Article  Google Scholar 

  7. 7.

    W.B. Doriese et al., Rev. Sci. Instrum. 88, 053108 (2017)

    ADS  Article  Google Scholar 

  8. 8.

    S. Okada et al., Prog. Theor. Exp. Phys. 2016, 091D01 (2016)

    Article  Google Scholar 

  9. 9.

    T. Hashimoto et al., IEEE Trans. Appl. Supercond. 27(4), 1–5 (2017)

    Article  Google Scholar 

  10. 10.

    T. Hashimoto et al., J. Low. Temp. Phys. (2020). https://doi.org/10.1007/s10909-020-02434-1

    Article  Google Scholar 

  11. 11.

    High Precision Devices (HPD), Inc., Cryostat Model 102 Denali. [Online]. http://www.hpd-online.com

  12. 12.

    W.B. Doriese et al., J. Low. Temp. Phys. 184, 389 (2016)

    ADS  Article  Google Scholar 

Download references


This work was partly supported by the Grants-in-Aid for Scientific Research (KAKENHI) from MEXT and JSPS (No. 18H05458). The authors are grateful to the members in the NIST Quantum Sensors Project. We appreciate the significant contributions by J-PARC, KEK, RIKEN, and those who have backed up the J-PARC MLF 2019A0083 experiment.

Author information



Corresponding author

Correspondence to S. Okada.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Okada, S., Azuma, T., Bennett, D.A. et al. X-ray Spectroscopy of Muonic Atoms Isolated in Vacuum with Transition Edge Sensors. J Low Temp Phys (2020). https://doi.org/10.1007/s10909-020-02476-5

Download citation


  • Transition-edge sensor
  • TES
  • X-ray spectroscopy
  • Muonic atom
  • QED