The total laser energy (3-32 J), temporal history (40 ns full width at half
maximum) and focal energy distribution (3 x 10(13) W/cm(2) peak, 1.5 x 10(
13) W/cm(2) average) for lambda = 1.06 mum Nd:glass laser interactions with
planar Al targets were measured. Laser-produced plasma emissions within th
e 1-3 keV x-ray range were recorded, with limited measurements in the 10-10
00 eV range. Primary emphasis was given to obtaining the dependence of kilo
volt x-ray emission on irradiance (varied by altering the energy on target
or the lens-target spacing). A maximum efficiency for the conversion of inc
ident laser energy to radiation above 1.5 keV was 0.25% into 2 pi sr. Integ
rated x-ray energy radiated over this range of photon energy was found to i
ncrease as the 3.2 power of laser energy at best focus. X-ray emission decr
eased when a prepulse preceded the main pulse by a controlled amount exceed
ing 0.2 mus but <5 mus, with a minimum emission at 0.5 mus separation. Plas
ma temperatures were estimated from x-ray line ratios and continuum slopes:
a value near 230 eV was obtained from free-bound continuum slope for 3 x 1
0(13) W/cm(2) peak irradiance. Temperatures decreased at lower irradiances,
as inferred from x-ray line ratios.