Congratulations, Christian on all the original research you you are investing in the early history of French semiconductors. The proposition in the article that Westinghouse did independently develop the point-contact transistor is of exceptional importance because it would be the perfect case study on an invention of monumental global significance arising out of similar circumstances on either side of the Atlantic. It is a perfect case study in technical innovation. Therefore just as Michael Riordan has recorded in detail the scientific thinking and actual experiments done that led to the Bell invention in Crystal Fire so too would more amplification of the French history be of huge value.
I know you agree but I am sure you would be assisted if this became more of a national French issue! We need research in the French archives where the original reports are waiting for us!!
Meanwhile, and too far away to be of real value to this cause, I have completed a translation of The Transiston Triode Type P.T.T. 601 which I hope will be of interest to English readers. As we all know no one in France ever challenged the primacy of the Bell invention and this is prefectly clear from the paper. Our readers need to undestand the semantics of "invention" which happens only once and for which Bell get the credit and "independently develop" in France which is entirely possible. Sadly, Sueur's paper does not assist answer this question. But it is of value on a number of fronts:
It gives more details on how the Transistron was constructed....in Section 3...N-type high resistivity germanium was polished and then etched with acid to expose a suitable crystalline surface structure which was then chemically treated to make (or enhance) a P type semiconductor layer. Wire point contacts of bronze, tungsten or molybdenum were then positioned on this surface... And in Section 4...The key to the production Transistrons lies in the preparation of germanium, in the selection of bars where pellets should be cut, in the search for points of contact and optimal adjustment of the spacing of the point contacts. These last two operations are carried out under the microscope and are made easier in the type 601 by the mechanical arrangements that are used...The paper does not explain quite what the significance of the correct positioning of the points was but reference to the Welker and Mataré patent discloses that they were exploiting polycrystaline germanium and positioning the points on either side of grain boundaries. Bell also used polycrystaline germanium early on but did not exploit it in this way. In their hands this material was a problem which they solved by using highly refined doped monocrystaline gernanium. From the point of view of the patent literature the Welker and Mataré invention was an improvement on the prior art of Bell. What we do not know is whether subsequent versions of the Transistron continued with this approach.
Of practical interest to collectors is that there were three versions of the Transistron at around the time of its launch in May 1949:
1. Three adjustable stems
2. One adjustable stem and a window cap
3. One adjustable stem and no window cap
Of these (1) and (2) are described or illustrated in the Sueur article and the third by other accounts of the launch such as Aisberg's Transistron = Transistor+ ? Toute la Radio No 137 and Aberdam's Transistor et Transistron in Ingénieurs et Techniciens No 12. (I am being somewhat ironic suggesting this information is of practical use for collectors since the only known examples of Transistrons of this vintage are at the Deutsches Museum, Munich. But who knows!!! Just as your article has enabled the identification of early Westectal diodes perhaps some early Transistrons still await discovery!)
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