Hyperfine splittings, prepulse technique, and other new results for collisional excitation neon-like x-ray lasers
The observation of hyperfine splitting on an X-ray laser transition is presented and the impact on the laser gain is discussed. We measure the lineshape of the 3p {yields} 3s(J = 0 {yields} 1) transition in neon-like niobium and zirconium and observe a 28 m{Angstrom} splitting between the two largest hyperfine components in the niobium(Z=41) line at 145.9 {Angstrom}, in good agreement with theory. In zirconium(Z=40), no splitting is predicted or observed since the hyperfine effect is proportional to the nuclear moment and this is present primarily in elements with odd Z. The hyperfine splitting is used to explain why the low-Z ions with odd Z have not lased. We discuss the use of a prepulse technique to achieve lasing in low-Z neon-like ions from Z = 22 to 32 on the 3p {yields} 3s(J = 0 {yields} 1) transition with wavelengths from 326 to 196 {Angstrom}. Using this technique on selenium(Z--34) we show a large enhancement of the J = 0 {yields} 1 transition at 182 {Angstrom} . Using a series of short pulses to drive selenium we observe the 182 {Angstrom} line to completely dominate the spectra. In an effort to reduce the large density gradients associated with hydrodynamic expansion, we discuss the use of low density foams for the laser target and present results which show lasing in zirconium aerogel with an initial density of 20 mg/cm{sup 3}. Finally, we discuss recent double slab experiments with ruthenium(Z--44) targets in which we observe lasing at 117 and 118 {Angstrom} for the first time.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10173502
- Report Number(s):
- UCRL-JC--116926; CONF-940592--6; ON: DE94016443
- Country of Publication:
- United States
- Language:
- English
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