Silicon Investigations Vacuum Tube Research and Custom Scientific Equipment Services
Vacuum tube technology has largely been relegated to the
history books. About the only applications where current vacuum tube
technology is still in use are in niche markets where tubes still out perform
solid state devices. Some examples are high power transmitting tubes
(power amplifiers, traveling wave tubes, magnetrons [microwave ovens], high
power switch tubes [thyratrons], and some specialty light sources like deuterium
lamps). There are, however, some cutting edge technologies where vacuum
tube science is being revisited to solve long standing roadblocks.
One such device is known as a vacuum transistor. This novel device
has the potential to operate in the THz (terahertz) frequency range where
conventional silicon semiconductor transistors can't go beyond the low GHz frequency
Another area where advances are being made is in the cathode design. In
traditional tubes, the cathode is heated by a filament to the point where
it emits electrons by thermal emission. This is why tubes draw so much
power, like a conventional light bulb. We are working on materials
that can emit electrons without being heated to incandescence, thus making
them more efficient. One such material is diamond like carbon (DLC),
which is a thin film of diamond deposited on a metallic substrate. DLC
has the potential to emit electrons without the high filament temperature needed for
We have a long history of building custom scientific apparatus for industry
and academia. Some examples of devices we have designed and constructed
are high voltage/current switching tubes (the krytron is one example), custom
light sources for raman spectrography and cryogenically cooled detector assemblies,
just to name a few.
Shown below are some research tubes we have developed to test new cathodes.
Cathode demonstration tube before evacuation.
Tube being evacuated while being heated with a IR laser beam to bake out contaminants.
Tube with low pressure diamond like carbon being grown
on the cathode. The bright spot is where the methane/hydrogen plasma
is depositing diamond like carbon on the cathode.
pumping station used to evacuate tubes and then back fill with the active
gas mixtures, as needed. We can provide tubes fully evacuated or with
custom gas mixes suitable to your needs, including argon, neon, krypton,
xenon, helium, and mixes of gasses. We can also add trace amounts of
mercury to gas filled tubes to promote long cold cathode life span.
Custom glass lathe used for vacuum tube construction and sealing. Both
the headstock and tailstock are driven synchronously to maintain registration
between the two tube parts.
Shown above are the spacer ring and optical filter for a
custom spectral tube prototype. The red filter has 13nm of chromium
coated around the perimeter.
The above image shows the assembled lamp
on the vacuum pumping station. The tube is then evacuated and back filled
with a neon gas mix to a pressure of 2.5 torr.
Above, the tube has been evacuated and
back filled with the neon mix and is running. The red spot projected
out of the top of the tube has the spectral properties needed for the project.
If you have any questions or would like to discuss a potential application
of our technology, please feel free to contact us.
call us at 920-955-3693 or email [email protected]