3 edition of Hollow cathode operation at high discharge currents found in the catalog.
Hollow cathode operation at high discharge currents
Verlin Joe Friedly
by Lewis Research Center, National Aeronautics and Space Administration, For sale by the National Technical Information Service in [Cleveland, Ohio], [Springfield, Va
Written in English
|Statement||by Verlin Joe Friedly.|
|Series||NASA CR -- 185238., NASA contractor report -- NASA CR-185238.|
|Contributions||Lewis Research Center.|
|The Physical Object|
A hollow-cathode lamp (HCL) is type of cold cathode lamp used in physics and chemistry as a spectral line source (for example, in atomic absorption spectrometers) and as a frequency tuner for light sources such as HCL takes advantage of the hollow cathode effect, which causes conduction at a lower voltage and with more current than a cold cathode lamp that does not have a hollow cathode. Decreasing the pressure in the hollow cathode discharge, simultaneously ensuring room for the expanding negative glow, allows the discharge to transit, from the hollow cathode type into a high voltage discharge where the cathode cavity is filled with the cathode glow. Such an arrangement seems to be very effective for endoergic charge transfer excitation as it was observed in a He-Cu : K. Rózsa, P. Mezei, P. Apai, M. Jánossy, S. Chinen, F. Howorka, I. Kuen, M. Grindhammer.
hollow cathode discharge mode, and the normal glow dis-charge mode. The cross section of the electrodes and a draw-FIG. 1. Electrode geometries for microhollow cathode discharges. FIG~a! End-on view of microhollow cathode discharges in argon at pressures of Torr for various discharge currents at wavelengths around nm. Abstract The low pressure glow discharges considered in this paper are the hollow cathode (Paschen), and the flat cathode (Grimm). Both discharges have similar voltage - current characteristics which are responsible for their radiation stability.
hollow cathode discharge (HCD) rather than in the hollow cathode arc (HCA) mode. The higher the con-tribution of Ti ions the more the phase is shifted to rutile. The grazing incidence XRD diagram from the anatase TiO film deposited on soda-lime glass is in2 Fig. 4. The M–M rf linear hollow cathode source was tested also in the low power File Size: KB. Microhollow electrode discharges, discharges between thin metal foils with submillimeter gap and submillimeter holes in cathode and anode, show three distinct modes of operation: (a) at low currents the predischarge mode, a glow discharge between the outer faces of the hollow electrodes, (b) at higher current a phase with increased ionization due to ``pendulum`` electrons in the cathode hole.
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Get this from a library. Hollow cathode operation at high discharge currents. [Verlin Joe Friedly; Lewis Research Center.]. measured on axis in the NEXIS hollow cathode at 25 A of discharge current.
The structure of the hollow cathode serves three main functions. First, some fraction of the thruster propellant is injected through the hollow cathode, and the discharge inside the resulting high neutral pressure region generates a cold, high-density plasma.
The principle of the hollow cathode discharge is to wrap the cathode around as much of the discharge volume as possible, thereby increasing the extent of the negative glow region and hence the number of ions formed in the discharge.
Van den Heuvel and Dymanus published an effective design  which has since been copied by many other is shown in Figure 3. Plasma Emission Characteristics From a High Current Hollow Cathode in an Ion Thruster Discharge Chamber John E.
Foster and Michael J. Patterson National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio The presence of energetic ions produced by a hollow cathodes operating at high emission currents (>5A) hasCited by: A high emission current hollow cathode that demonstrated operation at an emission current as high as J sub E = 40 A, and measurements which show the breakdown voltage of individual sections of the.
Hollow cathode discharges: Low and high-pressure operation researchers have applied these microplas mas to other fields, e.g., materials processing such as local et ching or deposit ion [ electrons in the discharge.
The breakdown voltage for a hollow cathode discharge in helium was calculated and compared to that of a glow discharge under similar conditions.
Hollow cathode discharges break down at lower volt- ages and carry order of magnitude higher currents com. Up to pressure times cathode hole diameter (pD) values of approximately 5 Torr cm, and at sub-mA currents, glow discharges (predischarges) are observed with a shape which is determined by the vacuum electric field.
In the same pD range, but at higher currents of up to approximately 4 mA, the discharges are of the hollow cathode discharge by: potential and temperature for different discharge currents and gas flow rates.
This data aids in a basic understanding of the hollow cathode physics and will ultimately assist in determining cathode life. Probing of thermionic hollow cathodes has been performed since they were invented by Lidsky1 in the A source for the continous production of neutral metastable atoms is described.
A hollow cathode discharge tube was used to produce densities of x 10/sup 13/ cm/sup -3/ and column densities of x 10/sup 15/ c cm/sup -2/ in the 4s/sup 2/ /sup 2/D metastable term of neutral copper. operating pressure during no-gas-flow cathode experiments is in the high Torr range.
Temperatures at various locations on a hollow cathode under test are measured using type C and K thermocouples. A typical hollow cathode is shown in Fig A toroidally shaped electrode (keeper) is.
the hollow cathode and flat discharge. A description of the hollow cathode developed at the National Hureau of Standards (NBS) will follow. The techniques used for the introduction of various conductive and non- conductive materials into the discharge will be discussed. The File Size: 2MB.
pD is Torr cm. The upper value of hollow cathode discharge operation is at a pD on the order of 10 Torr cm.4 Typically hollow cathode discharges are operated at sub-Torr pressures and cathode diameters in the centimeter range.
Experiments at higher pressures ~p Torr. in noble gases have been performed by Sturges and Oskam5 with parallel. greatly increased, and the discharge oscillations inherent in plume mode have been linked to cathode erosion and thruster instabilites.2 In order to develop design tools, an initial experimental investigation was conducted using laboratory model cathodes to determine the similarities and differences of low-power hollow cathode operation withFile Size: 2MB.
Troubleshooting and Maintenance of Atomic Absorption Systems: Part 1 - Hollow Cathode Lamps - Duration: Hollow Cathode Discharge II - - Duration: Jonathan Meyer views. The hollow cathode lamp is a type of glow discharge tube that uses a hollow cathode to enhance the emission intensity.
Compared to parallel plate electrodes, using a hollow cathode increases the current density by more than 10 times and this is accompanied by a significant increase in light emission intensity and a lower voltage drop in the lamp. The hollow cathode consists of two parallel aluminum plates and the discharge gas was a mixture of argon and nitrogen within the pressure range of 10 to 50 Pa.
A Helmholtz coil was used to produce a low intensity and uniform B-field along the axis of the discharge, within the range of (0 – 30) T. The discharge voltage was in the range of. A hollow cathode discharge cell has been developed for a variety of sample phases.
To make the experimental apparatus compact, we have adopted DC discharge, and the discharge cell was inexpensively constructed for replacement with commercially available vacuum parts. The most distinctive attribute of the developed cell is the double structure of the : Daisuke Ishikawa, Shuichi Hasegawa.
Selection of a Baseline Hollow Cathode We select a baseline hollow cathode design that has shown potential to reach high currents and long lifetimes. We will use this baseline as a basis for our calculations as well as a benchmark in future work. To select a baseline cathode type, a succinct review is useful to understand how emitters work.
Masamba, B. Smith, R. Krupa, and J. Winefordner, Atomic and ionic fluorescence in an inductively coupled plasma using hollow cathode lamps pulsed at high currents as excitation sources, Appl. Spectrosc.
42 () CrossRef Google ScholarCited by:. 当研究室で開発した「ホローカソードグロー放電チャンバー」 円筒状のカソード両側に穴をあけることで，プラズマの分光診断と静電プローブ.Gas-discharge starting of hollow cathode operation in self-heating mode D R Emlin and N V Gavrilov Institute of Electrophysics of the Ural Branch of the Russian Academy of Sciences, Amundsen St., Yekaterinburg,Russia E-mail: [email protected] Abstract.
The conditions of a gas-discharge starting of the massive metal cathode with remote.A detailed study of the spatial variation of plasma density, temperature, and potential in hollow cathodes using miniature fast scanning probes has been undertaken in order to better understand the cathode operation and to provide benchmark data for the modeling of the cathode performance and life described in a companion paper.
Profiles are obtained throughout the discharge and in the very Cited by: