The paper performs experimental issues from development and optimization of the selective cavity configuration in the electric-discharge DF laser for the lidar intended to monitor air methane. Using the selective resonator principle was shown to provide optimal feedback simultaneously at two selected wavelengths and allow us to form probing pulses consisting of in-time sequence of on- and off-lines. It was demonstrated experimentally that application of such a probing pulse would make it possible to build a simple and positivei-operation emitter-pickup system for lidar, provide the least mass/dimension values and consumed energy, and to enhance to operation safety of the entire complex.
The feature for DF laser ecology applications in its ramified spectrum. The DF laser energy distribution in selective and non-selective modes is investigated. The non-selective and selective outputs were 42.7 and 128 (totally) mJ accordingly.
The paper concerns with calculative and experimental development of a remote electric-discharge DF-laser analyzer for subterranean methane monitoring up to its explosive concentrations. The analyzer is built using a lidar scheme when the probing emission is reflected by artificial or natural object located in a subterranean measurement path. Methane records in the air are made using the differential absorption technique. The required metrological parameters of the analyzer are reached with the multi-frequency laser atmospheric control. A block diagram of the methane analyzer is given together with procedures to probe mine media with many frequencies in the spectral range from 3.6 to 3.8 μm. The lidar model was tested under conditions simulating physical values of the subterranean air: (1) methane air content -- up to 3% vol.; (2) dust content -- about 10 mg/m<sup>3</sup>; (3) probing path length -- about 50 m.
The paper concerns with calculative and experimental development of a remote electric-discharge DF-laser analyzer for subterranean methane monitoring up to its explosive concentrations. The analyzer is built according to lidar scheme when the probing emission is reflected by artificial or natural objects located on a subterranean measurement path. Methane records in the air are made using the differential absorption technique. The required metrological parameters of the analyzer are reached with the multi- frequency laser atmospheric control. The experimental factors of methane absorption in a spectral range from 3.6 to 3.8 micrometers and DF laser energy performance per line in a spectral range from 3.5 to 4.0 micrometers generated with a tunable selective resonator are performed. An excess of a factor 2 to 30 per the per line probing energy of the lidar operating with selective resonator over that with non- selective one is demonstrated. The probing energy of the lidar operating with selective resonator over that with non- selective one is demonstrated. The performed theoretical calculations determine the required power of providing radiation, optical on/off - line combinations of the laser, and measurement accuracy attained on measurement paths from 10 to 100 m long with the allowance for measurement- interfering factors under the conditions of detection of diffusively reflected lidar return form artificial and natural objects. A block diagram of the methane analyzer is given and procedures for multi-frequency probing of the mine medium are performed for a spectral range from 3.6 to 3.8 micrometers .
An applicability analysis of a DF laser in atmospheric remote control of SO<SUB>2</SUB> is performed: experimental absorption factors of SO<SUB>2</SUB> are given at various emission lines of a DF laser; possible errors from the spectral reflectance dependency for topographic objects are considered and the method of their correction is offered.
Chemical reactions are abundant sources of energy varieties concentrated in their excited products. This experimental fact constitutes the basis of the conception stated by Poolany J. C. in 1961, who offered to use exothermic chemical reactions for population inversion. This conception was implemented by Russian scientists A. N. Oraevsky and V. L. Tal'roze in their works. It was they who formulated the major requirements which chemical reactions must meet for effective lasing.
The DF laser's capabilities for monitoring natural gas and petroleum products in pipeline areas are considered. The absorption coefficients of methane, ethane, and propane were determine experimentally for 11 spectral lines in the 3.55- 3.75 micrometers range of the DF laser output. The criteria were formulated for selecting analytic and reference lines suitable for measuring atmospheric hydrocarbons by means of the differential absorption technique. Combinations of analytic and reference lines were chosen according to these criteria. The laboratory mock-up of hydrocarbon analyzer implemented around a DF laser was tested.
A brief review of the investigation results of chemical lasers based on the chain and nonchain reaction of fluorine with hydrogen (deuterium) made in the Russian Federal Nuclear Center (VNIIEF) is presented in this report.