The influence of residual atmosphere in magnetron to its output parameters

2004 ◽  
Author(s):  
G.I. Churyumov ◽  
T.I. Frolova ◽  
A.V. Gritsunov ◽  
O.M. Nikitenko ◽  
V.N. Zin'kovski
Keyword(s):  
Residual Atmosphere

Modelling of the residual atmosphere in vacuum devices with internal adhesive joints

Vacuum ◽  
2021 ◽  
Vol 184 ◽  
pp. 109964
Author(s):  
Boris S. Lunin ◽  
Valery A. Kreisberg ◽  
Robert A. Zakharyan ◽  
Mikhail A. Basarab
Keyword(s):  
Adhesive Joints ◽  
Residual Atmosphere

Nonevaporable Getters: Properties and Applications

MRS Bulletin ◽  
1990 ◽  
Vol 15 (7) ◽  
pp. 50-52
Author(s):  
F. Mazza ◽  
C. Boffito
Keyword(s):  
Surface Science ◽  
High Energy Physics ◽  
Diffusion Processes ◽  
Infrared Detector ◽  
High Energy ◽  
Main Role ◽  
Advanced Technologies ◽  
Vacuum Device ◽  
Residual Atmosphere ◽  
Traveling Wave Tubes

Many advanced technologies, such as surface science, semiconductor processing and high energy physics, call for vacuum levels of the order of 10−11 mbar and lower. These pressures can not be reached without a careful choice of materials, treatments, and evacuation means for the vacuum device involved. Non-evaporable getters (NEGs) are increasingly being recognized as an interesting and powerful solution for many vacuum problems. NEGs have been used extensively in sealed-off devices such as microwave tubes, traveling wave tubes, x-ray tubes, lamps, and infrared detector dewars, in which their main role is to assure the desired vacuum level throughout the life of the sealed device. The getter material can be considered as a chemical pump which removes the active gases in the residual atmosphere of the vacuum device by forming stable chemical compounds.The choice of materials, treatments, and structures of nonevaporable getter materials is critical for the optimization of the sorption and diffusion processes which are the basis of the NEG pumping mechanism. The effectiveness of this pumping mechanism at very low pressures, and the cleanliness and simplicity of operation have made this pumping approach ideal, in combination with other pumping technologies, for reaching the extreme high vacuums today's advanced technologies require. This article will explain the mechanism of the gettering process, describing materials, treatments, and structures used in standard vacuum practice, and will review some of the most typical and interesting applications.

The adhesion of evaporated metal films on glass

1961 ◽  
Vol 261 (1307) ◽  
pp. 516-531 ◽  
Keyword(s):  
Oxide Layer ◽  
Metal Films ◽  
Film Structure ◽  
Good Adhesion ◽  
Microscope Examination ◽  
Initial Adhesion ◽  
Residual Atmosphere ◽  
Glass Interface ◽  
Intermediate Oxide ◽  
Poor Adhesion

The adhesion of films of a large number of metals deposited by vacuum techniques on to a glass surface have been examined. It has been found that the affinity of the metal for oxygen plays an important role in determining the adhesion and the results appear to confirm the theory that the formation of an intermediate oxide layer at the metal/glass interface is necessary for good adhesion. There has been some doubt as to how this intermediate oxide layer is formed and the present investigation has shown that the nature and pressure of the residual atmosphere during deposition determines the extent of the formation of the oxide layer during deposition and therefore the initial adhesion of the films. However, variations in adhesion with time have been observed with films of a number of metals and it would appear that if the formation of the oxide layer is not complete during deposition then diffusion of gas to the metal/glass interface can continue the formation of the oxide layer after deposition thus accounting for the variation in adhesion with time. Since the film structure would determine the rate and extent of the diffusion of gas to the interface, it can be an important factor affecting the adhesion. Electron-microscope examination of a number of the films has been made and confirms the importance of the film structure. Furthermore, certain anomalies such as the poor adhesion of films of the low melting point metals and aluminium can be explained on the basis of film structure.

scholarly journals Sudden changes in the intensity of high energy X-rays from Sco X-1

1970 ◽  
Vol 37 ◽  
pp. 104-106
Author(s):  
P. C. Agrawal ◽  
S. Biswas ◽  
G. S. Gokhale ◽  
V. S. Iyengar ◽  
P. K. Kunte ◽  
...  
Keyword(s):  
Counting Rate ◽  
High Energy ◽  
Field Of View ◽  
X Rays ◽  
Background Counting Rate ◽  
X Ray ◽  
The North ◽  
Residual Atmosphere ◽  
Flux Gate ◽  
Background Counting

In this note we wish to report briefly the observation of sudden changes in the intensity of Sco X-1 by a factor of about 3 recorded in the energy interval 29.9–52.3 keV on December 22, 1968 between 04 h 27 m and 05 h 53 m UT. The observation was made with an X-ray telescope flown in a balloon from Hyderabad, India. The balloon was launched at 0200 hr UT and reached the ceiling of 7.5 g/cm2 of residual atmosphere at 0435 hr UT. The X-ray telescope consisted of a NaI(T1) crystal with an area of 97.3 cm2 and thickness 4 mm, surrounded by both active and passive collimators. The telescope was mounted on an oriented platform which was programmed to look in four specified directions successively, of azimuths, Φ=0°, 110°, 180° and 310° (Φ=0° being North and Φ=90°, West), spending about 4 min in each direction during a cycle of period of about 16 min. The axis of the telescope was inclined at an angle of 32° with respect to the zenith. A pair of crossed flux gate magnetometers provided information every 8.2 sec on the azimuth of the telescope. The pulse heights from the X-ray detector were sorted into several channels extending from 10 to 120 keV. An Am241 source came into the field of view of the telescope once in 15 min for about 30 sec to provide in-flight calibration of the detector. The meridian transit of Sco X-1 was at 0454 hr UT. Just before the balloon reached the ceiling Sco X-1 was in the field of view of the telescope for 3 min and 41 sec. After the balloon reached ceiling, Sco X-1 was in the field of view of the telescope on five occasions between 0443 and 0553 hr UT. During the last observation, however, the balloon had lost altitude by about 1 g/cm2. The excess counts due to Sco X-1 were obtained by subtracting the counting rates corresponding to the North direction which did not include any known X-ray sources. The observation on Sco X-1 in the 1st cycle was made while the balloon was still ascending and consequently the interposed grammage was changing from 10.5 to 9.7 g/cm2. However, for the energy range under consideration, the change in the background counting rate was not significant and there cannot be any doubt regarding the genuineness of the excess counts recorded.

Microstructure of TiC Layers on Iron and Carbon Steel Formed By Elevated-Temperature Ion Implantation

1985 ◽  
Vol 43 ◽  
pp. 286-287
Author(s):  
J. A. Sprague
Keyword(s):  
Elevated Temperature ◽  
Carbon Steel ◽  
Room Temperature ◽  
Carbon Steels ◽  
Target Chamber ◽  
Low Friction ◽  
Surface Layers ◽  
Active Elements ◽  
Residual Atmosphere ◽  
Sufficient Concentration

In several previous investigations, it has been shown that the implantation of carbon-active elements such as Ti, Hf, Ta, and Nb into Fe or steel specimens can produce low-friction, wear-resistant surface layers, provided that the implanted element is chemically bound to a sufficient concentration of carbon. For the case of room-temperature implants, the source of the carbon can be either a directly implanted layer or carbon that is adsorbed from the residual atmosphere of the target chamber. For these room-temperature implants, the surface layers consist of an amorphous Fe-Ti-C alloy. In more recent work, it was observed that the implantation of 5 x 1017 Ti/cm2 at 190 keV into Fe or carbon steels at temperatures between 600 and 800°C produced a near-stoichiometric crystalline TiC layer, approximately 60 nm thick, which was continuously graded in composition into the substrate. For pure Fe, the source of the carbon was shown to be the residual atmosphere, while for steels containing greater than 0.1 wt.% C, the source was the C in the alloy.

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