STORY ABOUT ELW1 TUBE
Interviev with dr Wiktor Sielanko -about story ELW1 tube

- You are the designer of the Polish counting tube ELW1. When and at what time the tube was developed?

-In 1955, probably in September, we chose subjects of diploma theses. At that time I was a student of electronics in Wroclaw. As a topic of work, I chose a counting tube, a type of vacuum decatron. This was before the creation of the Industrial Institute of Electronics, which was then called the Central Laboratory of Electronics.

- Earlier, a counting vacuum tube (E1T) was developed by Philips?

-Yes, but they did not patent this construction on Poland, which allowed for the development of the polish version of this tube. When I started to work, I got acquainted with the literature available on this subject at the time. Someone even brought a copy of the Philips E1T counting tube from the delegation. The construction of the lamp turned out to be quite difficult, at some point I even wanted to go to Prof. Witold Barwicz and change the title of the work.

-What was the difficulty?

The counting tube has a screen covered with a phosphor, called wilemite, which shines green. The test specimens made were working properly, starting from the number "5". However, before the tube counted up to five luminous signs were not visible. I thought about it for a long time and could not understand what caused it. In the end I understood: The reason was the negative charge of phosphor grains. At low voltages, so at the initial indication of the tube factor of secondary emission of wilemite is below than one. This means that it charges negatively and does not allow the flow of electrons and hence no light. In normal tubes, to avoid this phenomenon, the aquadag (graphite) bubble coated. It was out of the question in a tube calculating this way, because we would get a black, impermeable layer of colloidal graphite. Then, the chemist, Kazimierz Malikowski, came to my aid and suggested using a transparent one and a conductive layer based on tin chloride.

- ELW1 tubes were implemented to producing in the Experimental Workshop on Elekcyjna street.

- Yes, although I did not do it anymore. Then I came to a different position and participated in the development of low noise lamps with current wave for radar. This task brought me a lot of satisfaction when we went to the training ground and tested the developed tube. Airplanes could be seen on radars from over 200 km, when we exchanged the Soviet lamp for us. This testified to the success of the whole undertaking. But this is a completely different story.

- Thank you for the interview.