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Crespo Group

Max Planck Institute for Nuclear Physics

José Crespo López-Urrutia
José Crespo López-Urrutia.

The Crespo group is dedicated to the research of highly charged ions (HCI), developing methods for their production, trapping, and spectroscopy. In particular, it has initiated the field of laser spectroscopy of HCI with conventional lasers and X-ray lasers. The laboratory comprises three superconducting electron beam ion traps (EBITs), several non-cryogenic EBITs, two cryogenic RF traps for sympathetic ion laser cooling, various X-ray/Soft X-ray/VUV spectrometers, and related instrumentation. A VUV frequency comb for precision frequency measurements at high photon energies is currently under construction. The group has recently pioneered the field sympathetic cooling and crystallization of HCI [Schmoger et al. (2015)], searches for transitions sensitive to time-variation of fundamental constants [Windberger et al. (2015)], and, in the last decade, soft X-ray laser spectroscopy using free-electron lasers [Epp et al. (2007), Bernitt et al. (2012)], photoionization and resonant excitation of HCI with synchrotron radiation [Simon et al. (2010), Rudolph et al. (2013)], and optical laser spectroscopy with HCI [Mäckel et al. (2011)]. It closely collaborates with the German national metrology institute PTB (P. O. Schmidt) in the development of frequency metrology using trapped HCI, and with other experimental and theoretical groups at MPIK and elsewhere in the field of precision science with HCI.


Priv.-Doz. Dr. José Ramon CRESPO LÓPEZ-URRUTIA
Group Website

  • [1] L. Schmoger et al., "Coulomb crystallization of highly charged ions", Science 347, 1233-1236 (2015). [link to article]
  • [2] A. Windberger et al., "Identification of the Predicted 5s−4f Level Crossing Optical Lines with Applications to Metrology and Searches for the Variation of Fundamental Constants", Physical Review Letters 114, 150801 (2015). [link to article]
  • [3] S. W. Epp et al., "Soft X-Ray Laser Spectroscopy on Trapped Highly Charged Ions at FLASH", Physical Review Letters 98, 183001 (2007). [link to article]
  • [4] S. Bernitt et al., "An unexpectedly low oscillator strength as the origin of the Fe XVII emission problem", Nature 492, 225-228 (2012). [link to article]
  • [5] M. C. Simon et al., "Resonant and Near-Threshold Photoionization Cross Sections of Fe14+", Physical Review Letters 105, 183001 (2010). [link to article]
  • [6] J. K. Rudolph et al., "X-Ray Resonant Photoexcitation: Linewidths and Energies of Kα Transitions in Highly Charged Fe Ions", Physical Review Letters 111, 103002 (2013). [link to article]
  • [7] V. Mäckel et al., "Laser Spectroscopy on Forbidden Transitions in Trapped Highly Charged Ar13+ Ions", Physical Review Letters 107, 143002 (2011). [link to article]


Astrophysics EBIT Highly Charged Ions Ion Storage Ring Optical Spectroscopy VUV/EUV Spectroscopy X-Ray Spectroscopy