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1.
Kodymová J. Jirásek V. Schmiedberger J. ?palek O. ?ensky M. 《Optics and Spectroscopy》2009,107(5):816-825
Novel methods and device configurations for singlet oxygen and atomic iodine generation were proposed and investigated for
operation of the chemical or discharge oxygen-iodine lasers (COIL/DOIL). A chemical centrifugal spray generator of singlet
oxygen was developed, based on the conventional chlorine-basic hydrogen peroxide chemistry. Results of theoretical and experimental
investigation of the generator parameters are presented and compared with parameters of other generator types. A design of
experimental device for singlet oxygen generation by means of the hybrid DC arc and RF plasma jet is presented. An alternative
method of atomic iodine generation by a radiofrequency discharge decomposition of iodine compounds like CH3I or CF3I is described employing advanced experimental configuration. Some representative experimental results of this investigation
are presented. 相似文献
2.
J. Schmiedberger V. Jirásek J. Kodymová K. Rohlena 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):239-248
A novel concept of discharge oxygen-iodine laser (DOIL) is presented. The supersonic DOIL includes a discharge singlet oxygen
generator (DSOG) and discharge atomic iodine generator (DAIG). The operation of DSOG is based on a fast mixing of hybrid argon
plasma jet of DC electric arc and RF discharge with a neutral molecular oxygen stream. The goal of our effort is achievement
of DOIL oscillations by this new discharge technique, which should provide the singlet oxygen yields exceeding 30% at the
total pressures higher than 10 torr. The DAIG operation is based on a cw/pulse RF discharge dissociation of iodine donors
directly inside a laser iodine injector. This method substitutes the classic dissociation of molecular iodine by energy of
singlet oxygen, which saves its energy for laser generation and so can increase the laser efficiency. The laser power could
be thus enhanced by up to 25% if this method is employed in a chemical oxygen-iodine laser (COIL) operation, and even 3 times
in DOIL without increase in the iodine laser pumping by singlet oxygen. 相似文献
3.
J. Kodymová O. Špalek V. Jirásek M. Čenský G.D. Hager 《Applied Physics A: Materials Science & Processing》2003,77(2):331-336
This article addresses the development of a Chemical Oxygen-Iodine Laser (COIL) with alternative chemical ways of generating
atomic iodine. Injection of atomic iodine as opposed to molecular iodine has the potential to improve the COIL efficiency.
This paper describes two chemical methods for generating iodine atoms based on the gas phase reactions of hydrogen/deuterium
iodide with fluorine or chlorine atoms, which are also produced chemically. Simplified one-dimensional gas dynamic modeling
that describes the stream-wise profiles of species concentrations within both reaction systems is used to gain a theoretical
understanding of both reaction systems under COIL conditions. The modeling results are used for the design of an experimental
device and the interpretation of experimental data. The first experimental investigation studies the production of iodine
atoms produced from reactions of Cl with HI. Atomic iodine yields of 70–100% in nitrogen are obtained, and the gain on the
I(2
P
1/2)–I(2
P
3/2) transition in a flow of singlet oxygen is measured.
Received: 7 October 2002 / Accepted: 8 February 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +420-2/8689-0527, E-mail: kodym@fzu.cz 相似文献
4.
Jarmila Kodymová Otomar Špalek Vít Jirásek Miroslav Čenský 《Czechoslovak Journal of Physics》2004,54(5):561-574
Results of three problems investigated on a Chemical Oxygen-Iodine Laser (COIL) in our laboratory are presented in connection with the advanced COIL development in the world. These problems concern: i) A gain modulation on the laser transition in iodine atom, I(2P1/2) - (2P3/2), by external magnetic field, and its utilization for a COIL output power stabilization, ii) An evaluation of the Einstein A-coefficient of singlet oxygen, O2(1 g), and its utilization in advanced diagnostics for O2(1 g) determination in COIL operation, iii) A chemically driven iodine atom delivery system for advanced COIL. 相似文献
5.
A pulsed chemical oxygen-iodine laser (COIL) using atomic iodine generated by volumetric discharge of CH 3 I is developed and tested. COIL with a gain length of 60 cm is energized by a square pipe-array jet singlet oxygen generator with basic hydrogen peroxide pumping circulations and operated at subsonic gas flow. Maximum output energy of 4.3 J, pulse duration of 50 μs, specific energy extraction from the active medium of 2.0 J/L, and the maximum chemical efficiency of 12.5% are achieved at a chlorine flow rate of 55 mmole/s. 相似文献
6.
单重态氧发生器作为氧碘化学激光的核心部件,为化学激光器提供化学能。通过对工业喷射器及旋风分离器的研究,结合产生单重态氧的化学反应环境,进行了大量模拟及设计改进工作,研制了一种新型喷射型单重态氧发生器,并进行了相关实验研究。喷射型单重态氧发生器利用喷嘴能够产生比传统发生器类型更多的气液表面,获得足够的反应效率,可以大幅度降低发生器液体使用量,从而减小发生器辅助系统,提高体积效率。为满足O2(1)停留时间短及分离效率高的要求,利用气液两相喷射的高初速度以旋风分离器完成气液分离。新型发生器氯气利用率可达97%~99%,其O2(1)产率为40%~50%。 相似文献
7.
N. P. Vagin V. A. Zolotarev P. G. Kryukov V. S. Pazyuk Yu. P. Podmar'kov M. P. Frolov N. N. Yuryshev 《Journal of Russian Laser Research》1992,13(1):60-71
Conclusion It can be concluded from our experiments and calculations that the product CF3O2 of the interaction between the CF3 radical and the O2 molecule quenches the oxygen O2(1) more strongly. At low chlorine admixture density in the singlet-oxygen stream this output energy of the oxygen-iodine laser with CF3I as the atomic iodine donor is lower compared with CH3I. The rate constant of quenching singlet oxygen by CF3O2 molecules is (3–5)·10–11 cm3·sec–1. It would be possible to decrease the influence of CF3O2 by adding to the initial O2
*–O2–CF3I–Ar active mixture some other substance causing the CF3 radicals to enter in a chemical reaction with a shorter characteristic time than that for CF3O2 formation. Of course, neither the initial substance nor the reaction products should quench O2
* noticeably. This role can be possibly assumed by the NO molecule.The influence of the chlorine additive on the output energy of a laser with CH3I and CF3I differs greatly. The choice of the chlorine donor must therefore be determined by the amount of this additive. CH3I is preferable if the chlorine is fully utilized in the singlet-oxygen laser, and CF3I in the opposite case.Quantum Radiophysics Division, Lebdev Physics Institute. Translation of Preprint No. 21 of the Lebedev Physics Institute, Moscow, 1991. 相似文献
8.
N. P. Vagin D. G. Karapetyan A. F. Konoshenko P. G. Kryukov V. S. Pazyuk V. N. Tomashov N. N. Yuryshev 《Journal of Russian Laser Research》1994,15(3):213-242
Results of an experimental investigation of a chemical oxygen-iodine laser (COIL) are presented. We determine the factors
influencing the efficiency of a chemical singlet-oxygen generator (SOG) of the bubbler type operating on the chlorination
of an alkaline solution of oxygen peroxide. We describe SOG constructions. A cw COIL with output power up to 400 W is developed
on the basis of the investigated SOG. The feasibility of a modular construction of high-power COIL is demonstrated. A power-output
level of 1 kW was achieved with a two-section laser. The feasibility is analyzed of COIL operation in a pulsed regime by pulsed
bulk accrual of iodine atoms. We show that in this regime the laser can be operated without a low-temperature trap. An advantage
of such a regime is also the possibility of controlling, in a wide range, the lasing pulse duration. A strong influence of
molecular chlorine on the energy content of the active medium is observed when alkyliodides are used as iodine donors. The
possibilities of using a pulsed COIL for controlled thermonuclear fusion are discussed.
Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva Akademiya Nauk SSSR, Vol. 194, pp. 114–147 (1989). 相似文献
9.
10.
通过采用Cl2流量250mmol/s列管射流式氧发生器的COIL出光实验,得到了激光输出功率随碘副气流相对于氧主气流混合穿透深度的变化规律。实验结果表明,穿透深度对激光功率影响较大,存在最佳穿透深度,约为3.16mm,计算的最佳穿透深度与实验得到的最佳穿透深度基本一致。通过逐步改变供碘系统的碘气流流量,测量激光的输出功率,在实验上证实并找到了COIL的最佳碘流量值,约为4.5mmol/s,这一结果比以往文献所登载的最佳碘流量值要确切。 相似文献
11.
In this work, we studied the output power enhancement of an all gas-phase iodine laser (AGIL) by the addition of hydrocarbon
gases. Enhancement is expected because hydrocarbon gases might scavenge Cl atoms, which are strong quenchers of the upper
state of the laser medium, I(2
P
1/2). In AGILs, suppression of the Cl atom concentration is the key to improving the efficiency of the operation of the laser
because Cl atoms are inherently generated by the self-annihilation of the energy donor, NCl(a1
Δ). We found that the addition of CH4 gave the best results, because of its high scavenging rate constant and inertness to I(2
P
1/2). An enhancement of 10% was observed in the output power when CH4 was added at a flow rate twice that of NCl3. On the other hand, when C2H4 or C2H2 were added at the same flow rate as that of CH4, the output power reduced despite their fast removal rate of Cl atoms. The reason for the reduced output power was that the
unsaturated bonds scavenged not only the Cl atoms but also the H atoms, resulting in a low density of H atoms, and this decelerated
the production of NCl(a1
Δ). The observed laser characteristics could reasonably be explained by numerical model calculations. To our knowledge, this
is the first report of successful output power enhancement of an AGIL using a chemical agent. 相似文献
12.
V. Jirásek J. Schmiedberger M. ?ensky J. Kodymová 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(4):89
The dissociation of molecular iodine in 40 MHz-RF discharge was studied experimentally. This generation of atomic iodine is
aimed at use in oxygen-iodine lasers. The discharge was ignited in a mixture of I2 + buffer gas fast-flowing through the cylindrical chamber and the discharge products were injected into a supersonic flow
of nitrogen. The atomic iodine number density was measured in a low-pressure cavity after mixing with nitrogen and the dissociation
fraction was calculated related to the input I2 flow rate. The dissociation fraction of 46.2% was achieved at 0.22 mmol/s of I2 and 7 mmol/s of Ar and RF power of 500 W. Argon and helium were used as a buffer gas; discharge stability and dissociation
efficiency were better with argon. At the I2 flow rate corresponding to the operation of a 1 kW chemical oxygen-iodine laser, the dissociation fraction was about 20%.
The dissociation efficiency (the fraction of absorbed energy used for the dissociation) significantly decreased with increasing
in the specific energy. At a reasonable I2 flow rate (0.32 mmol/s), the maximum achieved efficiency was 8.5% and the corresponding energy cost was 8.9 eV per dissociating
of one I2 molecule. The input energy of more than 3 kJ per 1 mmol of I2 is needed for dissociating at least 50% of I2. The obtained dependencies on the gas flow rates infer a good chance for scaling-up of the tested RF discharge generator
for the intended application. 相似文献
13.
建立了激光在工作时的动态模型,即假设在单位时间内,激光介质的粒子数全部被泵浦到上能级。引入激光介质重复泵浦次数的概念,根据能量守恒原理,通过分析氧碘化学激光器(COIL)的传能机理,计算了沿气流方向变化的碘原子上能级的弛豫时间及沿气流方向变化的碰撞传能时间,并且计算了碘原子在出光区内被单重态氧反复泵浦的次数及相应的残余单重态氧数目,从而计算出碘原子在出光区的反复泵浦次数,修正了原计算COIL输出功率的公式。理论计算与实验结果均表明:当碘流量过低时,增益小于损耗,激光器不能起振;当增大碘流量时,激光输出功率也逐步增大,反复泵浦次数逐渐减少;当碘流量继续增大时,激光输出功率达到最大,且在一定碘流量变化范围内基本保持稳定;但随着碘流量的进一步增大,激光输出功率却逐步下降。 相似文献
14.
15.
16.
17.
A new regime of chemical oxygen-iodine laser (COIL), high-pressure subsonic mode operation, was demonstrated using a jet-type
singlet oxygen generator (SOG). The laser output power of 342 W with chemical efficiency of 20.9% was obtained at the Cl2 flow rate of 18 mmol/s and the operating pressure of 6.4 Torr in the laser cavity. The specific energy was 3.1 J/l which
was four times higher than our supersonic device, and was comparable to the highest value for the supersonic regime. The experimental
results were in good agreement with the numerical simulation results.
Received: 26 February 1999 / Revised version: 13 July 1999 / Published online: 30 November 1999 相似文献
18.
The He-Ar-Cu+ IR laser operates in a hollow-cathode discharge, typically in a mixture of helium with a few-% Ar. The population inversion
of the Cu+ ion levels, responsible for laser action, is attributed to asymmetric charge transfer between He+ ions and sputtered Cu atoms. The Ar gas is added to promote sputtering of the Cu cathode. In this paper, a hybrid modeling
network consisting of several different models for the various plasma species present in a He-Ar-Cu hollow-cathode discharge
is applied to investigate the effect of Ar concentration in the gas mixture on the discharge behavior, and to find the optimum
He/Ar gas ratio for laser operation. It is found that the densities of electrons, Ar+ ions, Arm
* metastable atoms, sputtered Cu atoms and Cu+ ions increase upon the addition of more Ar gas, whereas the densities of He+ ions, He2
+ ions and Hem
* metastable atoms drop considerably. The product of the calculated Cu atom and He+ ion densities, which determines the production rate of the upper laser levels, and hence probably also the laser output power,
is found to reach a maximum around 1–5 % Ar addition. This calculation result is compared to experimental measurements, and
reasonable agreement has been reached.
Received: 14 October 2002 /
Revised version: 28 November 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +32-3/820-23-76, E-mail: annemie.bogaerts@ua.ac.be 相似文献
19.
O. V. Braginsky A. N. Vasil’eva K. S. Klopovsky A. S. Kovalev D. V. Lopaev T. V. Rakhimova A. T. Rakhimov 《Laser Physics》2006,16(8):1161-1174
To understand and reveal the basic physical factors providing the possibility of scaling of a discharged singlet oxygen generator (DSOG) in an oxygen-iodine laser, the production, and transport kinetics of metastable O2(a 1δg) and O2(b 1σ g + ) molecules, as well as O(3 P) atoms, were investigated in Ar:O2 and He:O2 gas flows excited by a 13.56-MHz discharge in a wide range of pressures (4–40 Torr) and oxygen percentages. It is shown that the densities and transport kinetics of O2(a 1δg), O2(b 1σ g + ), and O(3 P) appear similar for oxygen mixtures with argon and helium in the same conditions independent of discharge mode. Compared to pure O2, the dilution of oxygen with an inert gas allows higher energy inputs per an oxygen molecule to achieved, especially under conditions of the homogeneous discharge mode (α-mode), which gives a higher efficiency of O2(a 1δg) excitation in Ar:O2 and He:O2 mixtures. But the maximum attainable yield of singlet oxygen in Ar:O2 and He:O2 at fixed partial O2 pressure is found to be comparable with the O2(a 1δg) yield in pure oxygen at the same pressure. The reason for this is the increased three-body deactivation of O2(a 1δg) by atomic oxygen in the mixtures because of the greater total pressure. The estimation of the rate constant of O2(a 1δg) three-body quenching by O(3 P) in Ar:O2 and He:O2 mixtures as (1.5 ± 0.5) × 10?32 cm6/s was carried out from the analysis of transport kinetics of singlet and atomic oxygen in the discharge afterglow at high pressures exceeding ~10 Torr. A similar analysis for the lower pressures has revealed that losses both of metastable O2(a 1δg) and O2(b 1σ g + ) molecules, and of O(3 P) atoms on the surface of the discharge tube, are determined by the density of each of the components. The obtained loss probabilities of O2(a 1δg), O2(b 1σ g + ), and O(3 P) on the silica surface show that the surface loss probabilities of all the species can increase noticeably under the discharge exposure. Thus, the key parameters determining the maximal O2(a 1δg) yield in the DSOG are a homogeneous volumetric mode of the discharge, energy input per oxygen molecule in this mode, and a low rate of O2(a 1δg) quenching. Just three-body quenching of O2(a 1δg) by O(3 P) limits the singlet oxygen yield with increasing pressure. The fast removal of atomic oxygen both in discharge and in the earlier afterglow could provide DSOG scaling with pressure. 相似文献
20.
V. N. Lokhman D. D. Ogurok E. A. Ryabov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):59-67
We report about effective ionization of iodine atoms and CF3I molecules under the action of intense XeCl laser radiation (308 nm). The only ion fragment resulting from the irradiation
of the CF3I molecules is the I+ ion. We have studied the influence of the intensity, spectral composition, and polarization of the laser radiation used on
the intensity
of the ion signal and the shape of its time-of-flight peak. Based on the
analysis of the results obtained, we have suggested the mechanism of this
effect. The conclusion drawn is that the ionization of the iodine atoms by
the ordinary XeCl laser with a nonselective cavity results from a three- (2 + 1)-photon REMPI process. This process is in
turn due to the presence of accidental two-photon resonances between various spectral components of the laser radiation and
the corresponding intermediate excited states of the iodine atom. The probability of ionization of the atoms from their ground
state I(2P3/2) by the radiation of the ordinary XeCl laser is more than two orders of magnitude higher than the probability of their ionization
from the metastable state I*(2P1/2). The ionization of the CF3I molecules by the XeCl laser radiation occurs as a result of a four-photon process involving the preliminary one-photon dissociation
of these molecules and the subsequent (2 + 1)-photon REMPI of the resultant neutral iodine atoms. 相似文献