CHARACTERIZATION OF LASER-PRODUCED PLASMA X-RAY SOURCES FOR USE IN X-RAY RADIOGRAPHY.

The absolute conversion efficiency xi //x from the incident laser light energy to X-ray photons is reported for laser-produced plasmas. Potential X-ray backlighting (radiography) line sources having photon energies from 1. 4 to 8. 6 kev are studied as a function of laser wavelength pulsewidth, and intensity. The laser intensity and pulsewidth range from 10**1**4 to 10**1**6 W/cm**2, 100 ps to 2 ns and include incident wavelengths of 1. 06, 0. 53, and 0. 35 mu m. Authors found that K-shell X-ray line emission xi //x: (1) decreases with increasing X-ray energy, (2) decreases with increasing laser intensity, (3) decreases rapidly with pulselength, and (4) moderately increases with decreasing laser wavelength. On the contrary, for Au M band emission, at a fixed laser intensity and pulsewidth, xi //x significantly increases upon decreasing the laser wavelength from 1. 06 to 0. 35 mu m.