Table 1 Actual and expected performance of IGLIS on 215Ac.

From: Towards high-resolution laser ionization spectroscopy of the heaviest elements in supersonic gas jet expansion

 

Gas cell

Gas jet (this work)*

Gas jet (projected) †

Ionization volume

 Pressure (mbar)

350 (15)

0.7–1

∼0.05

 Temperature (K)

350 (25)

25–30

∼9

 Jet divergence (deg.)

—

10–11

<1

Linewidth (FWHM)

 Total (MHz)

5,800 (300)

394 (18)

∼100

 Lorentz‡ (MHz)

4,000 (400)

42 (6)

<10

 Gauss§ (MHz)

1,400 (100)

280 (30)

∼100

Selectivity||

8.3 (17)

121 (27)

>3,000

Efficiency (%)

0.42 (13)

0.40 (13)

>10

  1. One s.d. uncertainties in the reported values are given between parentheses.
  2. *Information based on experimental data, except for the ionization volume parameters that are deduced from known equations12 for a nozzle, characterized in fluid-dynamics simulations at Mach number ∼6.
  3. †Predictions and extrapolations of the gas-jet results for working conditions at Mach 10.
  4. ‡Singled-out contribution due to gas collisions and the natural linewidth (∼4 MHz). We obtained the latter from MCDHF calculations of the atomic transition rate (A=2 × 10−5 s−1).
  5. §Singled-out contribution from gas temperature and laser linewidth, and in case of the gas jet data also the jet divergence.
  6. ||Ratio between the 215Ac ion production with lasers on- and off-resonance.
  7. Ratio between the 215Ac ions entering the mass separator to the 215Ac nuclei stopped in the buffer gas.
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