Slitless VUV spectra of the eclipsed Sun were obtained from a rocket experiment for the first time during the 1970 eclipse. The spatially resolved spectra of a quiescent prominence in the wavelength range 900 A.-2200 A_ consist of emission lines from ions formed in the temperature range 3.5 • 104K-3.2 • 105K. The spectral intensities have been interpreted in terms of physical parameters which indicate a transition zone of sheIMike layers, the inner the cooler and thinner, the outer the hotter and more extended. The transition zone is about 3 km thick for a model thread of 2000 km in diameter.

A longitudinal, discharge-heated copper vapor laser with an internal diameter of 4.2 cm and a length of 150 cm has been constructed. At the charging voltage of 14.5 kV, buffer gas pressure of 20 Torr, pulse repetition rate of 6.5 kHz, and laser tube temperature of 1450 °C; the laser offers an average power of 25 W with excellent stability and requires a minimum amount of maintenance.

Abstraet. An Aerobee 150 was launched into the umbra from Wallops Island at 18:36:15 UT 7 March, 1970, carrying two intensity calibrated EUV Wadsworth grating spectrographs. The experiment was a collaborative venture between groups from A.R.U. Culham, H.C.O., Imperial College and York University, Toronto. This was the first attempt to record stigmatic spectra of the chromosphere and corona in the EUV, analogous to the visible eclipse Flash Spectrum.A wealth of new observational data has demonstrated the importance of a new instrumental and experimental technique for recording the ultraviolet flash spectrum. Lyman-~ limb spectroheliograms reveal complex activity extending high into the corona in contrast to the modest level of activity observed in H~. Preliminary intensity reduction shows that Lyman-~ dominates as the principle radiation loss for these features.

The preionized metal vapor jet of a roomtemperature metal vapor laser Method for the preparation of protective coatings by lowtemperature metal-organic chemical vapor deposition (MOCVD) Rev. Sci.It is found that the appearance of high reverse-voltage spikes on the thyratron anode in the discharge of metal vapor lasers due to high laser impedances can easily be monitored by a dc current meter in series with the bypass inductor of the discharge circuit. Experiments are demonstrated using a copper vapor laser. Results show that the proposed impedance monitor is effective, reliable, and economical. The meter deflection corresponding to acceptable, wellbehaved thyratron operation can be obtained easily by the residual ionization-control method using a clean laser tube. By keeping the deflection within a specified limit, the lifetime of thyratron can greatly be extended.