The
Sprytron
The Sprytron, otherwise known as the Vacuum Krytron, is a device of very
similar performance to the Krytron. Though it generally exhibits a somewhat
lower time delay after triggering. The Sprytron is designed for use in
environments were high levels of radiation are present. The sprytron is a hard
vacuum 'filled' device unlike the krytron which, as noted above contains a low
pressure gas.
The Sprytron has only three leads, (no keep alive), but is otherwise very
similar in outward construction to the Krytron. The reason for the use of a
vacuum filling is almost certainly that there is no medium present for radiation
from the external environment to ionize (such ionization could promote spurious
triggering effects.)
The Sprytron requires a more powerful trigger pulse than the Krytron, as the
device works by forming an arc directly between the trigger and the cathode,
which causes the tube to breakdown (go into conduction) by disrupting the field
between the anode and cathode.
A Sprytron is triggered in a similar fashion to Krytron, but as mentioned
requires a higher energy trigger pulse and therefore a more powerful trigger
transformer etc. EG&G makes trigger transformers optimized for use with
their various tubes, and also make devices named Krytron-Pacs which incorporate
a gas filled krytron and trigger transformer in a single housing.
One final point: It is interesting to note that in application circuits (the two
references below, 1 and 2) the sprytron is always shown directly switching a load (an
Exploding bridge Wire.) and a Krytron is always shown triggering a secondary
device such as a triggered spark gap.
EG&G Catalogues/ Material. (RE: Components)
High Speed Pulse Technology by Frank Frungel -Academic Press. (RE: EBW's, FCG's, components)