X-ray emission from charge exchange of highly-charged ions in atoms and molecules

Jason Greenwood, Ian Williams, S.J. Smith, A. Chutjian

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed at JPL to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections. The ions are produced by the JPL HCI Facility and passed through a neutral-gas target cell. The product charge states are analyzed by a retarding potential difference technique. Results are made absolute by measuring target pressure, and incident and product ion currents. X-rays emitted from the product ions are detected with a Ge solid-state detector having a resolution of approximately 100 eV. X-ray astronomy has taken major steps forward with the recent launch of the high-resolution satellites Chandra and Newton. The cross sections reported herein are essential for the development of the solar wind comet interaction models inspired by these observations.
Original languageEnglish
Pages (from-to)150-152
Number of pages3
JournalPhysica Scripta
Publication statusPublished - 2001

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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