Performance of the ASTERIX III high power iodine laser
For more than 500 shots the 1 TW iodine laser Asterix III has demonstrated high reliability for light-plasma-interaction experiments. Improved laser parameters and new measurements of light pulse properties are reported.
Repetitively pulsed iodine laser with thermal gas flow cycle
The 1.315 mu m atomic iodine laser has been developed for repetitively pulsed operation by the use of a thermally driven fast gas flow and replenishment system. The flow, produced by thermal evaporation and condensation, removes the molecular iodine formed by photolysis which acts as a strong laser quenching agent. An all-glass construction of the laser and flow system gives long life sealed-off operation, and no iodine corrosion problems. Fluorocarbon buffer gases have been evaluated for use in providing flexibility in the operation of temperatures of the flow system in projected larger aperture oscillator systems, and for enhancing energy storage capability by pressure broadening the laser linewidth in Q-switched oscillators and amplifiers.
Recalculation of Mass Defects
THE well-known mass defect curve of the old nuclear scheme calculated with regard to α-particles and protons presented a difficulty with its minimum of binding energy for tin and an increasing portion between tin and lead. On the other hand, the mass defect values against protons give a rather smoothly decreasing curve.1 As has already been pointed out,2 the number of α-particles must be considerably reduced from the point of view of the new scheme, which does not admit any electrons in nuclei, but only neutrons and protons (presumably joined as α-particles). The curve of mass defect against protons and neutrons (perhaps with a single ‘central’ α-particle) is very similar to the old curve against protons, but decreases less rapidly. Clearly the new mass defect values relatively to α-particles, neutrons and protons must lie somewhere between the old values computed relative to protons and α-particles respectively (because the number of α-particles is decreased). We may emphasise that this new mass defect curve shows no increasing portion between tin and lead. For illustration we give two typical values: Old: 50Sn124 = 31α + 12&#38;epsiv;; mass defect = 0.158 (in mass units); 82Pb208 = 52α + 22&#38;epsiv;; mass defect = 0.035. New: 50Sn124= 25α + 24ω (ω = neutron); mass defect = 0.304; 82Pb208 = 41α + 44ω; mass defect = 0.366.