Oleg A. Rulev

Influence of nitrogen oxides NO and NO2 on singlet delta oxygen production in pulsed discharge

The influence of nitrogen oxides NO and NO2 on the specific input energy (SIE) and the time behaviour of singlet delta oxygen (SDO) luminescence excited by a pulsed e-beam sustained discharge in oxygen were experimentally and theoretically studied. NO and NO2 addition into oxygen results in a small increase and decrease in the SIE, respectively, the latter being connected with a large energy of electron affinity to NO2. The addition of 0.1–0.3% nitrogen oxides was experimentally and theoretically demonstrated to result in a notable enhancement of the SDO lifetime, which is related to a decrease in the atomic oxygen concentration in afterglow. It was experimentally demonstrated that to get a high SDO concentration at the gas pressure 30–60 Torr for a time interval of less than ~0.5 s one needs to add not less than 0.2% nitrogen oxides into oxygen. The temperature dependence of the relaxation constant for SDO quenching by unexcited oxygen was estimated by using experimental data on the time behaviour of SDO luminescence.

Transverse gas flow RF slab discharge generator of singlet delta oxygen for oxygen-iodine laser

Results of experimental and theoretical study of singlet delta oxygen (SDO) production in transverse gas flow RF slab discharge for an electric discharge oxygen-iodine laser are presented. The electric discharge facility operating in both pulse-periodic and CW mode was manufactured: gas flow duct including multi-path cryogenic heat exchanger, dielectric slab channel, and slab electrode system incorporated in the channel for RF discharge ignition. Experiments on SDO production in transverse gas flow RF discharge were carried out. SDO production depending on gas mixture content and pressure, gas flow velocity, and RF discharge power was experimentally studied. It was shown that SDO yield increased with gas pressure decrease, gas flow deceleration and helium dilution of oxygen at the same input power. CW RF discharge was demonstrated to be the most efficient for SDO production as compared to pulse-periodic RF discharge with the same averaged input power. SDO yield was demonstrated to be not less than 10 percent. The model developed was further modified to do simulations of CW and pulse periodic RF discharges. A reasonable agreement between experimental and theoretical data on SDO production in CW and pulse-periodic RF discharges in oxygen is observed.

Singlet delta oxygen production in self-sustained and non-self-sustained slab discharges

Singlet delta oxygen O2(a1Δg) (SDO) production in a slab discharges ignited in oxygen gas mixtures was experimentally studied. An influence of gas mixture content and input electric power on SDO yield was analyzed. In self-sustained RF slab discharge SDO yield of 10±5% was measured by comparison luminescence intensity of SDO going from a chemical generator and SDO generated in electric discharge. SDO yield of 7.2% was measured by intracavity laser spectroscopy method. It was demonstrated that the choice of electrodes material is very important. Experiments on SDO production in slab non-self-sustained discharge with external ionization by repeating high-voltage pulses were carried out. SDO concentration was measured by the method of intracavity laser spectroscopy. The measured concentration of SDO was about 1.5 1016 cm-3, with SDO yield of ~10.6%. A development of electric discharge oxygen-iodine laser with SDO production in long electrodes slab discharge is discussed.

Influence of nitrogen oxides on singlet delta oxygen production in pulsed electric discharge for oxygen-iodine laser

Experimental and theoretical study of influence of nitrogen oxides NO and NO2 admixtures in oxygen containing gas mixture excited by pulsed electron-beam sustained discharge on input energy and time behavior of singlet delta oxygen (SDO) luminescence was carried out. Temperature dependence of the constant of SDO relaxation by unexcited molecular oxygen was estimated.

Singlet delta oxygen production in a slab discharge in oxygen

Singlet delta oxygen O2a1&Dgr;g (SDO) production in a slab discharges ignited in oxygen gas mixtures was experimentally studied. An influence of gas mixture content and input electric power on SDO yield was analyzed. In self-sustained RF slab discharge SDO yield of 10±5 % was measured by comparison luminescence intensity of SDO going from a chemical generator and SDO generated in electric discharge. SDO yield of 7.2 % was measured by intracavity laser spectroscopy method. It was demonstrated that the choice of electrodes material is very important. Experiments on SDO production in slab non-self-sustained discharge with external ionization by repeating high-voltage pulses were carried out. SDO concentration was measured by the method of intracavity laser spectroscopy. The measured concentration of SDO was about 1.5×1016 cm-3, with SDO yield of ~10.6 %. A development of electric discharge oxygen-iodine laser with SDO production in long electrodes slab discharge is discussed.

Gas‐Flow Slab RF Discharge as a Source of Singlet Delta Oxygen for Oxygen Iodine Laser

Results of experimental and theoretical study of singlet delta oxygen (SDO) production in transverse gas flow RF slab discharge for an electric discharge oxygen‐iodine laser are presented. The electric discharge facility operating in both pulse‐periodic and CW mode was manufactured: gas flow duct including multi‐path cryogenic heat exchanger, dielectric slab channel, and slab electrode system incorporated in the channel for RF discharge ignition. Experiments on SDO production in transverse gas flow RF discharge were carried out. SDO production depending on gas mixture content and pressure, gas flow velocity, low‐frequency modulation of RF power and RF discharge power was experimentally studied. It was shown that SDO yield increased with gas pressure decrease, gas flow deceleration and helium dilution of oxygen at the same input power. CW RF discharge was demonstrated to be the most efficient for SDO production at the same averaged input power of RF discharge. SDO yield was demonstrated to be not less than...

Influence of nitrogen oxides NO and NO2 additives on singlet oxygen production in pulsed electron-beam sustained discharge

Influence of nitrogen oxides NO and NO2 on specific input energy (SIE) and time behavior of singlet delta oxygen (SDO) luminescence excited by pulsed e-beam sustained discharge in oxygen was experimentally and theoretically studied. NO and NO2 addition into oxygen results in small increase and decrease of SIE, respectively, the latter being connected with large energy of electron affinity to NO2. The addition of 0.1-0.3% nitrogen oxides was experimentally and theoretically demonstrated to result in notable enhancement of SDO lifetime, which is related to a decrease of atomic oxygen concentration in afterglow. There was experimentally demonstrated that for getting high SDO concentration at gas pressure 30-60 Torr for the time interval less than ~0.5 s one needs to add not less than 0.2% nitrogen oxides into oxygen. Temperature dependence of relaxation constant for SDO quenching by unexcited oxygen was estimated by using experimental data on time behavior of SDO luminescence.

Singlet oxygen in the low-temperature plasma of an electron-beam-sustained discharge

Results are presented from experimental and theoretical studies of the production of singlet delta oxygen in a pulsed electron-beam-sustained discharge ignited in a large (∼18-1) volume at a total gas mixture pressure of up to 210 Torr. The measured yield of singlet oxygen reaches 10.5%. It is found that varying the reduced electric field from ∼2 to ∼11 kV/(cm atm) slightly affects singlet oxygen production. It is shown experimentally that an increase in the gas mixture pressure or the specific input energy reduces the duration of singlet oxygen luminescence. The calculated time evolution of the singlet oxygen concentration is compared with experimental results.

Time behavior of small-signal gain on high vibrational transitions for pulsed CO laser amplifier with gas mixtures CO:He, CO:N2, and CO:O2

Small-signal gain time behavior for cryogenic pulsed e-beam sustained discharge CO laser amplifier on high (V>15) fundamental band vibrational transitions was studied experimentally for different CO containing gas mixtures including ones typical for CO lasers and amplifiers (CO:He and CO:N2), and CO:O2 used for singlet delta oxygen production.

Small-Signal Gain Time Behavior on High Vibrational Transitions (V>15) of Pulsed CO Laser Amplifier

Small-signal gain time behavior for a pulsed e-beam sustained discharge CO laser amplifier operating on fundamental band vibrational transitions V → V-1 from 6 → 5 (λ ~ 5.0 μm) up to 32 → 31 (λ~7.5 μm) was studied both experimentally and theoretically at various parameters of active medium. Special attention was paid to the small-signal gain time behavior on high vibrational transitions (V > 15). As was previously shown by us, multi-quantum theoretical model of vibrational exchange has to be applied for a correct description of a CO laser operating on vibrational transitions V → V-1 with V higher than 15 instead of a single-quantum one. To make easier theoretical interpretation of the experimental results, the binary nitrogen free gas mixture CO:He = 1:4 was used in our experiments. Total gas density and initial gas temperature was 0.12 Amagat and ~100 K, respectively. The complete kinetic model of a CO laser taking into account multi-qauntum vibrational exchange was employed for theoretical description of the small-signal gain time behavior. The theoretical results were compared with the experimental data.