Impact of observed hyperfine splitting on X-ray laser gain

Conference · Mon Nov 01 04:00:00 EST 1993

OSTI ID:10118165

Nilsen, J; Koch, J A; Scofield, J H; MacGowan, B J; Moreno, J C; Da Silva, L B

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, the authors present cases where the hyperfine effect is the dominant line broadening mechanism. Studying laser lines, which tend to have gain narrowed linewidths, enables one to observe these dramatic hyperfine effects which would be difficult to observe in opacity or Stark broadened lines. In this work the authors 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 the experiments they 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 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. The authors 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 and helps explain their poor performance.

• 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: 10118165
• Report Number(s): UCRL-JC--114568; CONF-9311168--1; ON: DE94005822
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002
661300
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAM OPTICS
DOPPLER BROADENING
GAIN
LASERS AND MASERS
OTHER ASPECTS OF PHYSICAL SCIENCE
X-RAY LASERS