Measurement of spatial gain profiles in multiple pulse driven Ne like Ge lasers

Conference · Sun Jun 01 04:00:00 EDT 1997

OSTI ID:632781

Nilsen, J; Moreno, J C; Barbee, T W; Da Silva, L B

We present the first direct spatial measurement of the two dimensional gain profiles for a Ne-like ion using a slab target illuminated by the multiple pulse technique. To understand the spatial dependence of the gain in Ne-like Ge on the 19.6 nm laser line for plasmas driven by a series of 100 ps pulses 400 ps apart we did a series of Nova experiments backlighting short Ge amplifiers. Two-dimensional, high-resolution, spatial images of the 19.6 nm laser emission from the output aperture of the amplifiers were measured to determine the spatial position of the gain. The amplifier lengths were chosen to be short enough to avoid significant refraction of the beam. In previous imaging experiments which measured the near field output of the Ge laser, the position of the laser output was dominated by refraction effects. To assure good temporal overlap, we used the traveling wave geometry to illuminate both the amplifier and backlighter. The amplifier design included a wire fiducial which provided an absolute spatial reference and avoided the usual difficulty of determining the location of the target surface. We compare the measured gain with simulations done using LASNEX, which calculates the hydrodynamic evolution of the plasma, and XRASER, which uses the temperature and densities from LASNEX to do the gain and kinetics calculations.

• 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: 632781
• Report Number(s): UCRL-JC--125818; CONF-970706--; ON: DE98050260
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COMPUTERIZED SIMULATION
GAIN
IMAGES
PLASMA
PULSE TECHNIQUES
TESTING
X-RAY LASERS