Effects of spatial nonuniformity of superconducting-tunnel-junction ion detectors on mass spectroscopy

M. Ohkubo*, M. Ukibe, N. Saito, A. Kushino, S. Ichimura, S. Friedrich

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Spatial uniformity of superconducting tunnel junction detectors with a size of 200 μm is improved by increasing Al thickness of the Nb/Al proximized electrodes in an energy range of 5-10 keV. which is in the same order as an acceleration energy in time-of-flight mass spectroscopy (TOF-MS). It has been confirmed in the TOF experiments with Ta ions and Ta clusters that the proximized junction detectors clearly separate different ionic states and multi-hit events in impact energy spectra, and moreover can reveal the difference in ion species or ion-surface collision dynamics. However, a better spatial uniformity is not always good for TOF-MS, possibly because a detector with the thicker Al layers has a lower superconducting energy gap, which results in an improper detector operation because of a temperature rise due to heat radiation, or the states of the detector surfaces are different.

Original languageEnglish
Pages (from-to)932-935
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number2 PART I
Publication statusPublished - 2005 Jun
Externally publishedYes


  • Mass spectroscopy
  • Particle detectors
  • Superconducting radiation detectors
  • Superconductor-insulator-superconductor devices

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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