  A new electron beam-optical procedure is proposed for quasi-cw pumping of
high-pressure large-volume He-Ar laser on 4p[1/2]1 - 4s[3/2]2 argon atom
transition at the wavelength of 912.5 nm. It consists of creation and
maintenance of a necessary density of 4s[3/2]2 metastable state in the gain
medium by a fast electron beam and subsequent optically pumping of the upper
laser level via the classical three-level scheme using a laser diode.
Absorption probing is used to study collisional quenching of Ar* metastable in
electron-beam-excited high-pressure He-Ar mixtures with a low content of argon.
The rate constants for plasma-chemical reactions Ar*+He+Ar-Ar2*+He (3.6 +-
0.4)x10-33 cm6/s, Ar+2He-HeAr*+He (4.4 +- 0.9)x10-36 cm6/s and
Ar*+He-Products+He (2.4 +- 0.3)x10-15 cm3/s are for the first time measured.
