This tube is part of a series of tubes developed for a CSIRO research project that culminated in 1951, in a decade counter that could count from 0 - 9999 pulses (or oscillations). It is an example of the first of the series of tubes made by hand in the CSIRO Electrotechnology laboratory at the University of Sydney to designs developed experimentally by David Hollway. Hollway describes it as being "used to test the principle of setting up stable positions of an electron beam by feeding back the beam current to control the voltages on the deflector plates." A number of the tubes were made and the version that Hollway demonstrated at the 1951 Exhibition of Scientific Instruments in Melbourne had four digits.
This tube and other objects donated by David Hollway represent the first attempt to develop a single vacuum tube electronic counting device that was also fast enough to record the frequency of high speed events such as the signals output from an ionization chamber during experiments in nuclear physics. Although there were several existing electronic counters, having been originally developed by Wynn-Williams in 1931, they consisted of considerable numbers of vacuum tubes of standard design. As Hollway notes: "In 1947, when the counter tube project was proposed, electronic counters were used chiefly for nuclear research and some electronic instruments. Each scale-of-ten required at least four twin triode vacuum tubes, or pentodes and a number of passive components. For each decade, 10 lights, or a meter with a scale marked 0-9, was needed to display the count. A gas-filled counter tube was in production overseas but was limited in speed." [Hollway's notes]
This new design represents an early attempt to integrate the multiple component functions of existing counters into a single electronic device. It used a complex set of components to respond to (count) a sequence of electronic pulses, hold (store) the current count and display it. A carryover signal was also generated to allow a set of the devices to count to at least four digit numbers (0-9999). The display was an additional aspect of the accumulation process in which the currently stored value (from 0-9) was presented as a fluorescent figure on the end of the tube. Previous electronic counters used a meter or a set of separate lights to indicate the current count.
The development process was also significant in its use of simulation techniques and analogue computing to confirm the path of the electron beam under the effect of the deflection components proposed for the device. This simulation process itself resulted in the publication of several important papers. [see below for references]
The project ran from 1947 to 1951 and had garnered interest from overseas; however it was abandoned due to the recent development of transistors for electronics and the recognition that they would soon replace vacuum tubes in high speed electronics.
Regarding the decade counter:
Nature, vol.6, p.856, May 27, 1950.
Electronics, May, 1952, pp.152-154
Australian Journal of Physics, vol.6, no.1, March 1953, pp.96-115.
Regarding the theory and simulation of electron flow:
Australian Journal of Scientific Research, A, vol.5, no.3, 1952, pp.430-436.
Australian Journal of Physics, vol.8, no.1, 1955, pp.74-89.
Proc. Inst. Electrical Engineers, vol.103, part B, no.8, 1956, pp.155-165.
Jnl. British Inst of Radio Engineers, vol.24, no.3, 1952, pp.209-211.