Impact of observed hyperfine splitting on X-ray laser gain

Conference · Tue Jan 10 04:00:00 EST 1995 · AIP Conference Proceedings (American Institute of Physics); (United States)

OSTI ID:6615044

Nilsen, J; Koch, J A; Scofield, J H; MacGowan, B J; Moreno, J C; Da Silva, L B ^[1]

---

1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

Line broadening mechanisms play an important role in determining the gain of X-ray laser transitions. Typically Doppler broadening is the primary mechanism which determines the linewidth of these transitions. However, we will present cases where the hyperfine effect is the dominant line broadening mechanism. Studying laser lines, which tend to have gain narrowed linewidths, enables us to observe these dramatic hyperfine effects which would be difficult to observe in opacity or Stark broadened lines. In this work we report the observation of hyperfine splitting on an X-ray laser transition and discuss how hyperfine splitting has a major impact on the laser gain. In our experiments we measure the lineshape of the 3p[r arrow]3s, J=0[r arrow]1 transition in neon-like niobium and zirconium and observe a 28 mA splitting between the two largest hyperfine components in the niobium (Z=41) line at 145.9 A, in good agreement with theory. In zirconium (Z=40), no splitting is observed since the hyperfine effect is proportional to the nuclear moment, and zirconium has zero nuclear moment, as is typical for even-Z elements. The hyperfine effect is shown to effect transitions which have a 2p[sub 1/2] vacancy in the closed neon-like core much more than those with a 2p[sub 3/2] vacancy. A comparison of the neon-like niobium laser spectrum with that of zirconium shows a dramatic reduction in the relative intensity of the niobium laser lines with the 2p[sub 1/2] vacancy. We also report the unusual behavior noticed recently in low-Z neon-like X-ray lasers in which ions with odd Z lase poorly, if at all, relative to ions with even Z. The hyperfine effect is shown to have a substantial impact on the gain of the low-Z ions with odd Z and helps explain their poor performance. [copyright] 1995 [ital American] [ital Institute] [ital of] [ital Physics]

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6615044
• Report Number(s): CONF-9309119--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Journal Volume: 322:1
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
664200 -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
AMPLIFICATION
CHARGED PARTICLES
ELEMENTS
GAIN
HYPERFINE STRUCTURE
IONS
LASERS
LINE BROADENING
METALS
MULTICHARGED IONS
NIOBIUM
STARK EFFECT
TRANSITION ELEMENTS
VANADIUM
X-RAY LASERS
ZIRCONIUM