COMPARISON OF NEON-LIKE GERMANIUM INNER-SHELL AND NICKEL-LIKE GADOLINIUM LASING AT 62 ANGSTROM AND 66 ANGSTROM BY PICOSECOND HEATING OF A PREFORMED PLASMA

Simulations are presented to compare the output of the 62 Angstrom inn er shell transition in germanium with the 66 Angstrom traditional J = 0 --> 1 gadolinium transition, using 280 ps pulses with a maximum of 1 00 J energy and a 30 J, 3 ps pulse, of peak intensity 1.5 x 10(15) W c m(-2), focussed onto a 1 cm long, 100 mu m wide slab target. Saturated output appears possible for gadolinium assuming the implementation of a suitable travelling wave pumping scheme. Saturation was achieved in this configuration using two long pulses of peak intensity 8 x 10(12) W cm-2 and the CPA pulse, leading to an output power of similar to 14 MW. Under these pulse restrictions, the germanium inner shell does no t achieve saturation. Simulations indicate that saturation may be achi eved if the CPA pulse intensity is fractionally increased (to similar to 2 x 10(15) W cm(-2)). The output power of germanium is similar to 1 MW, due to a smaller near field area Raytracing for both schemes pred icts a far field deflected angle of similar to 3 mrad. Simulations ind icate the potential of these schemes for successful X-ray lasing at wa velengths of similar to 65 Angstrom. (C) 1998 Elsevier Science B.V. Al l rights reserved.