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Visualization of the Gas-Phase Emitter Effect of Dysprosium in Ceramic Metal Halide Lamps
Michael Westermeier;Oliver Langenscheidt;Jens Reinelt;Juergen Mentel;Peter Awakowicz
The gas-phase emitter effect of dysprosium is demonstrated by high-speed photography, spectroscopic, and pyrometric measurements at a high-pressure mercury lamp doped with Nal/Tll/Dyl3, which is operated in a transparent yttrium-aluminia-garnet tube with an f = 100 Hz switched dc current.Show More
Numerical investigation of different modes of arc attachment at tungsten cathodes in dependence on the electrode geometry
2008 IEEE 35th International Conference on Plasma Science
Year: 2008 | Conference Paper |
Summary form only given. Diffuse and spot-like modes of arc attachment at thermionically emitting cathodes are observed in lamps and reproduced by numerical simulations. Examples of different modes on rod shaped electrodes made of pure tungsten were investigated by measurements in the Bochum model lamp being operated with argon at a pressure of p=0.26 MPa. The corresponding simulations are based o...Show More
Power balance of HID lamp electrodes under HF operation
Jens Reinelt;Michael Westermeier;Peter Awakowicz;Juergen Mentel
2008 IEEE 35th International Conference on Plasma Science
Year: 2008 | Conference Paper |
Operating HID lamps with high frequencies is not yet a commonly used method. It is assumed that the efficacy of the whole lamp system including the lamp driver can be improved with higher operating frequencies as it has already been done for low pressure lamps. Indeed the increasing frequency will lead to changes in the electrode physics which may cause a different lamp behavior Thus the Bochum mo...Show More
The gas-phase emitter effect and the formation of an emitter-spot-attachment in ceramic metal halide lamps
M. Westermeier;O. Langenscheidt;J. Reinelt;P. Awakowicz;J. Mentel
2008 IEEE 35th International Conference on Plasma Science
Year: 2008 | Conference Paper |
Summary form only given. The behavior of electrodes operated with alternating currents in ceramic metal halide lamps containing Hg+NaTlDy-iodide has been investigated experimentally. Transparent YAG lamp tubes have been used to perform phase resolved measurements of the electrode temperature and Dy-densities in dependence on the cold-spot temperature of the salt filling. The electrode temperature ...Show More
To support modelling of the electrodes in high intensity discharge lamps a model lamp was realized for precise caloric and electrical measurements at the electrodes. In this model lamp the properties of electrodes made of pure and modified tungsten were investigated in a current range between 1-10 A in dependence on the electrode geometry. The electrodes were operated in Ar or Xe in a pressure ran...Show More
Summary form only given. This work is part of investigations aiming at "Fundamental Characterization of Thermionic Cathodes". In order to verify and further develop models of the cathode boundary layer, measured values of the cathode fall are of great importance. In this paper a method is introduced with which the cathode fall can be determined from measurements of the local plasma potential in an...Show More
Summary form only as given. Show More
Spectroscopic determination of W I and W II oscillator strengths
IEEE Conference Record - Abstracts. 1997 IEEE International Conference on Plasma Science
Year: 1997 | Conference Paper |
Summary form only given, as follows. Oscillator strengths of 43 W I and 27 W II lines in the wavelength range 240-560 nm have been measured with a wall-stabilized arc. The arc was operated at 10-80 A in argon at atmospheric pressure with an admixture of tungsten hexafluoride. A set of relative W I and W II f-values was determined by a combination of emission and absorption measurements with a spec...Show More
Spectroscopic investigation of arc spot ignition on cold cathodes
IEEE Conference Record - Abstracts. 1997 IEEE International Conference on Plasma Science
Year: 1997 | Conference Paper |
Summary form only given. To investigate the ignition of arc spots on cold cathodes under defined conditions a special experimental set-up was developed. An arc ignited between two horn electrodes in a pure argon gas atmosphere is blown magnetically against a third so called commutation electrode which is negatively biased against the arc plasma. The ignition of arc spots on this cathode was invest...Show More
Investigations of the ignition of arc spots on cold cathodes in a noble gas atmosphere
To investigate the ignition of arc spots on cold cathodes under defined conditions, a special experimental setup was developed. An arc ignited between horn electrodes in a pure argon gas atmosphere is blown magnetically against a third so called commutation electrode, which is negatively biased against the arc plasma. The ignition of arc spots on this cathode was investigated by electrical measure...Show More
Electrical investigation of the interaction of a dense plasma with cold electrodes in air
The magnetic blowing of an arc against a third so-called commutation electrode positioned perpendicularly to the discharge axis allowed the investigation of a reproducible interaction of the plasma with this electrode. Cathodic arc spots were ignited on the commutation electrode with a negative-biased voltage and anodic spots with a positive-biased voltage. The delay times of arc spot ignition on ...Show More
Optical investigation of the interaction of a dense plasma with cold cathodes in air
The magnetic blowing of an arc against a third so-called commutation electrode positioned perpendicularly to the discharge axis allowed a reproducible interaction of the plasma with this electrode to be achieved. Cathodic arc spot ignition was viewed on commutation electrodes made of Cu, Au, and Ni. High-speed photography revealed that arc spot ignition is initiated either by a luminous layer corr...Show More
Analysis of arc spot ignition on cold lamp electrodes
IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting
Year: 1996 | Conference Paper |
Cited by: Papers (2)
The ignition of arc discharges in lamps does not proceed straightforwardly in many cases. The discharge remains in the state of a glow discharge since the formation of an arc spot at the cold cathode does not take place. To investigate the arc spot ignition on cold cathodes under defined conditions, a special experimental setup was developed. An arc ignited between horn electrodes in a clean argon...Show More
Optical investigation of arc spot formation on cold cathodes in noble gas atmosphere
An arc ignited by a high-voltage breakdown in pure argon at atmospheric pressure is blown magnetically against a third so-called commutation electrode (CE) positioned perpendicularly to the arc axis. Cathodic arc spot formation is initiated on this electrode by application of a potential difference between the bulk plasma and the commutation electrode. The first stage of this current transfer is i...Show More
CW radio-frequency excited white-light He-Cd/sup +/ laser
We report on the design and performance of a continuous-wave transverse capacitively coupled radio-frequency excited He-Cd/sup +/ laser, which is capable of simultaneously delivering stable, tens-milliwatt power output at the three primary spectral lines blue: (/spl lambda/=441.6 nm), green (/spl lambda/=533.7 nm and /spl lambda/=537.8 nm), and red (/spl lambda/=635.5 nm and /spl lambda/=636.0 nm)...Show More
First Page of the Article
Show MoreDetermination of the spectrally resolved gain profile of HeSe/sup +/ laser lines from the beat frequency spectrum
Several laser lines are selected from the multiline spectrum of a CW HeSe/sup +/ laser by an intracavity birefringent filter. The different axial modes of a laser line move across the gain profile because of statistical variations of the resonator length. The laser modes are recorded as beat frequencies in the GHz region by a fast photodiode and a spectrum analyzer. Variable losses are inserted in...Show More
Measurement of arc spot formation delay times at cold cathodes in air
The column of a high current arc is magnetically blown against a cathode positioned perpendicularly to the arc axis. A linearly increasing voltage is applied to this electrode. The delay time of the arc spot formation which initiates the arc commutation was measured for smooth electrodes made of Cu, steel, graphite, Mg, and Ce. The cumulative frequency distribution of this delay time was found to ...Show More
Optical investigation of arc spot formation on cold cathodes in air
The column of a high current arc was magnetically blown against a cathode positioned perpendicularly to the arc axis. A linearly increasing voltage was applied to this electrode. It was shown by high-speed photography that the arc spot ignition is initiated by an intensified light emission on the cathode within an area of approximately 40- mu m diam. SEM micrographs from the traces produced during...Show More
Spectroscopic investigation of a low current arc in pure fluorine
A pure fluorine 10-A DC arc has been operated in an Al/sub 2/O/sub 3/ tube of 18 mm diameter at atmospheric pressure. This arc was used to perform radially resolved spectroscopic end-on measurements in the visible and UV-spectral regions. An excitation temperature of 7800 K on the arc axis was determined from the intensity of atomic fluorine lines, and an ion density of 1.7*10/sup 21/ m/sup -3/ wa...Show More
Fluorne Arc of Low-Current Strength and Its Optical Spectrum
A pure fluorine dc arc is operated in an Al2O3 tube. At each end of the tube a pair of tungsten electrodes is connected with the tube via copper cascades. The main tube is fed with a permanent flow of fluorine while the electrodes are protected from the same by separate argon flows. At the constricted red column of a fluorine arc at 10 A the spectrum was recorded end-on. It consists essentially of...Show More
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