Ceramic Discharge Tube Research Articles

The Sodium Transport in Polycrystalline Alumina

In this work we present the investigations on the determination of the mechanism of sodium loss in High Pressure Sodium (HPS) lamps. The transport through the ceramic arc tube consists of several steps (solution in the ceramics, diffusion through the ceramics, leaving the bulk phase, evaporation from the surface). Among the listed processes the mechanism of the diffusion was investigated by model-experiments. A ceramic arc tube was applied as a reactor chamber, in which polycrystalline ceramic plates were heated at 600-1100°C in controlled Na and Xe atmosphere. The sodium diffusion profiles developed by the heat-treatment were measured by XPS and SIMS and from the measurements we tried to draw a conclusion about the mechanism of sodium diffusion through the ceramic discharge tube. The ceramic discharge tube were measured by X- ray diffraction, too. We found traces of some Na-O-Al compound.

The Sodium Loss and Transport through the Walls of the Ceramic Discharge Tube of High Pressure Sodium Lamps

In this work we present the investigations on the blackening of the outer jacket of the High Pressure Sodium (HPS) lamps. For this purpose ceramic arc tubes and their glass outer jackets taken from lamps burned for different times (0h-10000h) were examined by X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectroscopy (SIMS) in order to determine the composition of the deposit on the internal wall of glass outer jacket. In the case of the several thousand hours burned lamps the outer bulb was found to be covered by aluminium, which comes to a black deposit on the glass surface. XPS identified Al on the glass surface can be found in two different chemical state (elemental Al, Al2O3). The assumed evaporation of aluminium-oxide ceramic tube might be described by a dissociative mechanism of the alumina evaporation. This papers described the possible mechanism of the alumina evaporation. Na was also found in the black deposit, whose cause of this in the case of the several thousand hours burned lamps is probably related to the sodium transport through the walls of the arc tube

Evaluation of High-Frequency Sinusoidal Waveform Superposed With Third Harmonic for Stable Operation of Metal Halide Lamps

In this paper, a novel topology to supply metal halide (MH) lamps using sinusoidal waveform with superposed third harmonic is proposed. By employing this technique, the lamp is supplied with an approximated square waveform, but it reduces the harmonic content and, therefore, electromagnetic interference and radio-frequency interference. The proposed topology is analyzed and designed for a 35-W MH lamp with ceramic discharge tube. Experimental results prove that lamp operation is stable at operating frequencies where acoustic resonances were previously observed when supplied with purely sinusoidal waveforms. In conclusion, the proposed technique could be a feasible solution for stable operation of MH lamps.

一般照明用150Wセラミック発光管メタルハライドランプの検討

一般照明用150Wセラミック発光管メタルハライドランプの検討

A high efficiency ion source for Kr and Xe isotopic measurements

We report tests performed on a microwave plasma ion source to determine its suitability for high sensitivity Kr and Xe isotopic analysis. The source consists of a 1.3 cm o.d. × 15 cm long ceramic discharge tube with excitation provided by a 2.45 GHz λ/4 cavity. We have developed a technique to generate ⩾ 2 × 10 −11 A of Xe ions directly from air, with an ionization efficiency of 2%. Measurements of the isotopic compositions of Kr and Xe in air samples agree with the atmospheric values to within 0.5%. This result implies good ion beam stability and lack of serious isobaric interferences. The memory effect when alternating between Xe samples with extremely different isotopic compositions is at the 1% level. The microwave ion source appears very promising for isotopic analysis.

A compact nitrogen laser for long-term stable operation

The design of a compact transversely excited nitrogen laser with transverse turbulent gas flow is discussed. Its rectangular beam (7*16 mm2) makes it suitable for dye-laser pumping. The differential efficiency is eta d<or=1.10/00. All parts are made of long-term stable and resistant materials. The main characteristics are: a ceramic discharge tube, W-Cu electrodes, thyratron switching with low jitter and ceramic storage condensers. A new interpretation of the reduction of the laser output with increasing repetition rate is given.

Measurement of the stimulated emission cross section in a waveguide CO2laser

An experimental method is described for determining the stimulated emission cross section σ of a gas laser. The method was used to measure σ for the 00°1–10°0 vibrational transition of the CO2 molecule in a compact waveguide laser having a beryllia ceramic discharge tube. The determination of σ was based on an experimental measurement of the luminescence drop at 4.3 μ wavelength, and of the laser output power at 10.6 μ wavelength. The value of σ0 measured at zero photon flux density in the waveguide resonator, for a gas mixture Xe–CO2–N2–He at a pressure of 6.65 kPa, was 1.84×10−18 cm2. The effective value of the upper active-level lifetime of the CO2 molecule was also determined.

Short ceramic waveguide CO2–laser amplifier

A study was made of a 4-cm long BeO ceramic discharge tube having a 1×1 mm square-section discharge channel. Measurements were made of the dependences of the gain on the pump intensity and on the gas pressure, for gas mixtures having different compositions and percentage content of CO2. An analytical expression was obtained for determining the gas temperature which takes into account the pump parameters and the thermal conductivities of the gas mixture and of the tube material.

The Laboratory production of solar iron lines in the vacuum Ultraviolet

The Scylla plasma which is contained in a ceramic discharge tube has been purposely contaminated with known impurities. The spectrum of the discharge with Fe (CO)5 added shows most of the solar lines in the 150–220 Å region. Some of these strong lines may be produced by iron in intermediate stages of ionization (Fe X to Fe XIV).

X-Ray Crystal Spectroscopy of a Theta-Pinch Plasma in the Region 15-25Å

A new synthetic crystal, potassium acid phthalate (KAP), has a spacing between crystal planes, $2d=26.6$ \AA{}. The use of this crystal in a Bragg crystal spectrometer has permitted measurement of the Scylla I x-ray spectrum from 15 to 25 \AA{}, a region inaccessible with the beryl crystal previously used. The principal features of the observed spectrum in this region are the lines of O vii and O viii arising from oxygen contamination of the discharge by material from the ceramic discharge tube. Six lines of the resonance series of O vii are observed, including both $1{s}^{2}^{1}S_{0}\ensuremath{-}1s2p^{1}P_{1}$ and $1{s}^{2}^{1}S_{0}\ensuremath{-}1s2p^{3}P_{1}$. The first members of the Lyman series of O viii are also observed. Measurements of Doppler widths of the lines of O vii and O viii yield an oxygen-ion Doppler temperature of 9.3\ifmmode\pm\else\textpm\fi{}2.8 keV. These measurements, when combined with those previously made on other ion species, show that the ions of the plasma are not in collisional equilibrium.