**5. Conclusions**

nm was detected and the band of 495–460 nm in Kr-Xe was registered for the first time [148]. Two emission systems were observed, in 600–670 and 670–685 nm regions, whenXe was added to Kr flowing afterglow at a pressure of 30 Pa [149]. Kugler [150] obtained similar results for Ar-Xe mixture and discovered new band in Ar-Kr in the region of 605–642 nm. He explained these bands as transitions of neutral heteronuclear molecule formed in the processes of

In 1975, Tanaka et al. [151] have published data on radiation spectra of 10 pair mixtures of inert gases in the region of 100–700 nm. Molecular bands observed in radiation spectra in the discharge were identified as transitions between states of heteronuclear ionic molecules:

pressure in an electric discharge in paired mixtures of inert gases has up to 5 similar bands

Kinetics of Ar-Kr, Ar-Xe, and Kr-Xe mixtures' excitation by low activity 241Am alpha parti‐ cles was studied in [152, 154]. Constants of processes rates in these mixtures were identified;

when excited by 210Po alpha particles with activity of ~0.5 Cu investigated in [153, 155–157] determined the rate constants of processes of formation and destruction of levels of hetero‐ nuclear ionic molecules. In [153] includes first noted high luminescence efficiency of (ArXe)+

(KrXe)+ at pumping by ionizing radiation. Luminescence of Ar-Xe mixture pumped by powerful electron beam was studied in [158], attempts to obtain lasing on transitions of

In [42] was built kinetic model of Ne-Ar mixture relaxation pumped by a hard ionizer with

plasma chemical reactions, calculations show that lasing is only possible at high pressure

0.05–0.25%. In this work were considered the triple (with Kr) instead of the binary mixtures of inert gases, as the authors suggested that the constant of deactivation rate of the lower level

may occur negligible. It was assumed that the lower laser level will be deactivating in the

NeAr Ar Ar Ne <sup>2</sup>

at pumping by an electron beam had yield negative results [155, 158].

regard to the possibility of lasing on transition Ne+

(above 16 atm) and powerful pumping (1 MW/cm3

[151], there are no transitions from levels corresponding to the states of atomic ions 2

153] when excited by ionizing radiation of medium- and high-pressure mixtures.

however, constants' values of a number of processes are underestimated: ~10−15 cm3

N asymptotically correspond to states of M+

; here M, N—atoms of inert gases, and N—a heavier atom. If the plasma of low

/s for three-particle processes. Emission of Ar-Xe and Kr-Xe mixtures

Ar→NeAr<sup>+</sup>

M N MN hν + + ® + (27)

+N, and MN+

. When using typical rates of

), and lasing efficiency should not exceed

+ + +® + (28)

to the

P3/2 [152,

/s for two-

,

metastable atoms of argon.

184 186High Energy and Short Pulse Lasers

where molecular states of M+

particle and ~10−34 cm6

in exchange processes:

processes with Kr atoms:

(ArXe)+

state of M+N+

Nuclear-pumped lasers are of great interest as the way to extract high-quality energy from a nuclear reactor core. Presently achieved pulse power of NPL in quasi-continuous mode exceeds 1 MW. However, the most promising active media on transitions of inert gas atoms have a number of disadvantages: relatively low efficiency, radiation in IRregion, low operating temperature. There is no clarity as to the basic mechanism of upper laser level population: direct excitation by secondary electrons, excitation transfer from buffer gas atoms, electronion recombination of molecular ions (dimers or heteronuclear ions). This area requires further research.

#### **Acknowledgements**

This work has been supported by the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. 0681/GF4). Authoris grateful to staff of the WWR-K reactor and DC-60 accelerator for their assistance in conducting experiments.
