Measurement of a magnetic-dipole transition probability inXe32+using an electron-beam ion trap

Abstract

The transition probability for the 3d 4 5 D 2 ← 5 D 3 magnetic-dipole transition in Ti-like Xe ͑Xe 32ϩ ) has been measured using an electron-beam ion trap. The unusually weak dependence of the transition energy on nuclear charge Z, and the fact that the transition wavelength remains in the 320-to 400-nm range for 54ϽZϽ92, makes this transition promising as a plasma diagnostic tool. Our measurement of the transition probability yields 465͑30͒ s Ϫ1 , corresponding to a lifetime of 2.15͑14͒ ms, in good agreement with the theoretical value of 2.4 ms. ͓S1050-2947͑97͒07506-9͔

Trapped highly charged ion plasmas

“…Complimentary data, taken under rather different EBIT operating conditions, have been reported in the PhD thesis of M. Tarbutt [44]. Both of these works were predated by some spatial information that was obtained by Serpa et al [50] in connection with the measurement of excited-state atomic lifetimes. In this work, the entire spectrometer table was mounted on sliding rails and was moved perpendicular to the EBIT observation direction by piezoelectric translators, allowing the transverse distribution of light at the entrance slit of the spectrometer to be mapped out.…”

“…The magnetic field was presented as a technical detail needed to adiabatically compress the electron beam to high densities at the trap center. From the onset of our work [7,50], however, we have taken a somewhat different view, which emphasizes the direct effect of the magnetic field on the ion confinement. With this point of view, we first reported an experiment that demonstrated that an EBIT can be used to measure some properties of highly charged ions (excited state lifetimes, for example) more efficiently when the electron beam is turned off [50].…”

“…From the onset of our work [7,50], however, we have taken a somewhat different view, which emphasizes the direct effect of the magnetic field on the ion confinement. With this point of view, we first reported an experiment that demonstrated that an EBIT can be used to measure some properties of highly charged ions (excited state lifetimes, for example) more efficiently when the electron beam is turned off [50]. This work was stimulated by some related work on ion cloud diagnostics at Livermore [53][54][55][56][57].…”

“…The effect of the magnetic field dominates only for large distances from the electron beam. Once the ions of the desired charge state are produced, the electron beam can be used for exciting electronic transitions for spectroscopic studies, or it can be turned off completely, leaving the axial confinement solely to the magnetic field [49,50]. Details of the modeling of ion creation [47] and the trapping dynamics [48] are described elsewhere.…”

Fine‐structure in 3d4 States of Highly Charged Ti‐like Ions

“…The dis crepancy dis ap pears ap par ently in high-Z re gion for the J = 3 2 tran si tion. One and only one avail able mea sure ment for Xe 32+ by Serpa et al14 is also plot ted in the fig ure.…”