3.6M north10.pdf - Dean-O's Toy Box
3.6M north10.pdf - Dean-O's Toy Box
3.6M north10.pdf - Dean-O's Toy Box
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Cathode Pulsers: Hard-Tube Modulators (10) 187<br />
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Shapeof sourceplasma<br />
Carrnaicanode insulator<br />
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arm! :magnets<br />
rid<br />
~ Hydrc@n.sarvoir<br />
l.- Mo~anum (cold)cathode<br />
Figure 10-29. Cross-section view of Crossatron odoff control switch.<br />
on. A negative pulse applied to the same grid will turn it off, much in the same<br />
fashion as a gate-turn-off (GTO) thyristor. The amount of current that can be<br />
gated off is unlikely to be as much as that which can be gated on, unless the grid<br />
construction of the tube is deliberately altered to optimize turn-off instead of<br />
turn-on.<br />
The ability of the device to emulate full-control+r at least 2/3 control, if one<br />
considers intrapulse-current-amplitude control as being worth l/3-derives horn<br />
the action of the crossed magnetic and electric fields. Figure 10-29 shows the<br />
cross section of a typical Crossatron. Its design is coaxial-cylindrical. It has an<br />
internal anode, its current flow is radial, and it has a cold molybdenum cathode<br />
and two grids. A continuous voltage is applied to the “source” grid, which<br />
stimulates a continuous “source” plasma. The magnets, which surround the<br />
tube, are radially magnetized. They produce alternating north and south poles<br />
that progress vertically up the tube and a magnetic field that matches the shape<br />
of the source plasma. A positive-going trigger pulse applied to the control grid<br />
attracts plasma into the region between control grid and anode and initiates full<br />
conduction between cathode and anode. A negative-going pulse applied to the<br />
control grid will reverse the process.