KEYWORDS: Molecules, Chemiluminescence, Molecular energy transfer, Optical resonators, Hydrogen fluoride lasers, Chemical lasers, Hydrogen, Visible radiation, Near infrared, Chemical species
The visible and near infrared spectra of cavity chemiluminescence of a combustion driven HF laser fueled by NF3 were collected and analyzed. The spectral line at 529 nm for the green chemiluminescence was attributed to electronic excited NF molecules in b1∑ state, i.e. NF(b). The diffuse bands from 570 nm to 700 nm were attributed to the N2(B-A) emission. The spectral lines from 850 nm to 1000 nm were attributed to the HF Δυ = 3 emission bands. At the end of every experiment, the spectral line at 874 nm would be observed, which was attributed to the electronic excited NF molecules in a1 Δ state, i.e. NF(a). The NF(a-X) emission was found experimentally to be always avoiding the HFΔυ = 3 emission bands. It was also found experimentally that the NF(b-X) emission always accompanied the HF Δυ = 3 emission bands and their emission intensities had the same trends as a function of experimental time. Whereas the NF(a) molecules was produced in the optical cavity directly by the reaction of H atoms with NF2 molecules in the incomplete combustion effluents, the NF(b) molecules were suggested to be produced mainly by the near resonant energy transfer from vibrational excited HF(v<=2) molecules to NF(a) molecules. In other words, the vibrational excited state HF(v<=2) molecules can be efficiently deactivated by the NF(a) molecules by near resonant V-E energy transfer process. Therefore we concluded that incomplete dissociation of NF3 might be harmful to the HF(v<=2) population.
KEYWORDS: Chemical lasers, Photonic integrated circuits, Pulsed laser operation, Control systems, Logic, Oxygen, Interfaces, Data acquisition, Laser development, Chlorine gas
A user-friendly data acquisition and control system (DACS) for a pulsed chemical oxygen -iodine laser (PCOIL) has been developed. It is implemented by an industrial control computer,a PLC, and a distributed input/output (I/O) module, as well as the valve and transmitter. The system is capable of handling 200 analogue/digital channels for performing various operations such as on-line acquisition, display, safety measures and control of various valves. These operations are controlled either by control switches configured on a PC while not running or by a pre-determined sequence or timings during the run. The system is capable of real-time acquisition and on-line estimation of important diagnostic parameters for optimization of a PCOIL. The DACS system has been programmed using software programmable logic controller (PLC). Using this DACS, more than 200 runs were given performed successfully.
A theoretical model is established to describe the α-RF discharge in slab Oxygen Iodine lasers, according to the
continuity equation of electron density, the electron energy equilibrium equation and the continuity equation of current
density. Assuming a Maxwellian energy distribution, the spatial distributions of electron density and electric field in RF
plasma are obtained by numerical method. The effects of parameters on discharge characteristics have been analyzed.
The results show that the current density has a big effect on the electron density in discharge area. The influences of
excitation frequency on the maximum value of electric field and the thickness of boundary layer are also discussed. And
the spatial distributions of electron energy and excitation efficiency of singlet delta oxygen have been calculated. The
influences of gas mixture on the excitation efficiency of singlet delta oxygen are discussed. It provides references of
parameters for slab discharge in singlet delta oxygen generating.
By means of radio frequency(RF) capacitively coupled discharge, pure CF3I and the mixture of CF3I and various inert gases were used to produce iodine atom for a chemical oxygen-iodine laser. The dependences of atomic iodine concentration on gas pressure and gas flow rate were studied. In the case of RF frequency of 13.56MHz, output power of 500W, gas pressure of 3.5Torr, pure CF3I without any carrier gas ,and CF3I flow rate of 1.2SLM, atomic iodine concentration of 4.0×1014 cm-3 was achieved. The concentration of atomic iodine was of the order of 0.4×1014cm-3 at p=15Torr in the case of the mixture of CF3I and some inert gases, which was lower by one order of magnitude than that of pure CF3I. A kinetics modeling was carried out and demonstrated that CF3 played dominant role in the loss mechanism of atomic iodine.
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