Self-focusing, spatially stable, electron beams arising from heating up to 160 0 C and cooling to room temperature pyroelectric LiNbO 3 crystals in dilute gases have been observed for the first time. The current (up to nanoamperes) and energies (up to 170 keV) of these electron beams attained maximum values and then decreased during the cooling phase of the thermal cycle. Cylindrical crystals produced spatially stable beams with typical focal lengths of 22 mm and 1mm spot sizes. Here we present photographic as well as electronic proof of their existence.

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Autoionization of He atoms following double excitation by electrons, protons, C~+ (Q =4-6), and Fo+ (Q =7-9) ions has been studied. The electron-emission yields from the doubly excited 2s ('S), 2s2p('P), and 2p ('P) states were measured at the reduced projectile energy of 1.5MeV/nucleon for observation angles between 10' and 60'. The results indicate excitation to the 2s'('S) and 2p~('D) states increases as approximately Q', while excitation to the 2s2P('P) state varies as approximately Q', where Q is the charge of the projectile. These charge dependences are significantly less than the Q dependence expected in the independent-electron model, suggesting the interaction between the two target electrons is important in creating the doubly excited states.

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A new effect, "gas amplification of electron energy" is reported here; namely when a cylindrical pyroelectric crystal such as (LiNbO 3 ) is contained in a concentric cylindrical chamber and is heated and then allowed to cool in a dilute gas the maximum energy of the resultant focused electron beam more than doubles as the pressure increases from 0.05 to 4 mTorr for seven different gases.