Hi folks,
I passed on Ed's comments to three folks who worked on UNSW's DEUCE: Robin
Vowels, Keith Titmus & John Webster. Here's a somewhat edited version of their
responses, plus photo.
Cheers,
John Deane
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English Electric DEUCE, eg University of NSW's "UTECOM" - Mushroom Memory
The memory consisted of 12 mercury filled delay lines. These were "folded" with
quartz crystal transmitter and receiver at the top and a pair of acoustic mirrors
at the bottom. See photo 1.
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The delay lines were arranged inside the periphery of an upright cylinder.
The transmitter and receiver driver electronics were arranged in a ring around
the top of the cylinder, so as to be close to the corresponding crystals in the
mercury delay lines. That provided easy access to mercury delay lines, and to the
receivers and transmitters, for maintenance. In the case of the delay lines, for
adjustment of position of the crystal transmitters for length of column and
direction. In the case of the transmitters/receivers, for ease of removal and
testing, connection and disconnection of cables. See photo 2.
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The temperature of the delay lines was maintained by heating the cylinder, under
thermostat control, to about 48 degrees C, within less than +/- 0.25 degrees C.
(those numbers should be checked). The mushroom shape was achieved only when the
lid was put on. It was shaped like an inverted dish so as to prevent heat
escaping. See photo 3.
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So, the cylindrical shape provided the smallest volume to be heated and allowed a
consistent, short distance from the delay lines to their driving electronics.
This was not an unstable shape. The lid was light (made from aluminium?). The
cylinder was the heavy part, and as its base directly beneath the mercury tanks,
was inherently stable.
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