Why we use thoriated tungsten cathodes? COST 529 Eindhoven, 2006.March.31. I.Gaal, L.Bartha.
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Transcript of Why we use thoriated tungsten cathodes? COST 529 Eindhoven, 2006.March.31. I.Gaal, L.Bartha.
Why we use thoriated tungsten cathodes?
COST 529
Eindhoven, 2006.March.31.
I.Gaal, L.Bartha
Electron emission micrographs of thoriated tungsten wire
Fig.1: As drawn, fibrous state. All others: Recrystallised state
All pictures are made at the same surface location. Time sequence: 6-8 sec between each part
Transport of W in halogen lamp
• 220V/650W halogen studio lamp labelled with W185 isotope
• Autoradiogram of filament sections after 10 hours of burning
..
• 220V/1000W halogen lamp labelled with Ta182 annealed
• 1.) 180V, 2 hours • Deposition on
surface• 2.) 220V, 8 hours• Diffusion into the
coil• 3.)Co 60 annealed 220V• Co deposition at the
central part, onto the inner side of the coil
0
0.5
1
1.5
2
2.5
3
0 500 1000 1500 2000
Time (min)
Rat
io o
f T
h t
o W
1400 K1500 K1600 K1700 K
IDC = 2.5 A --->>2.35 A A homérséklet végig állandó maradt. Csak az elektron áramsuruség értékében történt változás.