The german nuclear physicist Hans Geiger developed several counters for detecting radiation. All of them could only register alpha — and beta — rays in several different qualities and quantities. One of them was the “point counter” (Spitzenzähler) Geiger designed in 1913. The tubecounter developed by him and his assistant Walter Mueller in 1928 is in matters of function nearly equivalent to his predecessor. But the so called “Elektronenzählrohr” exceeded the point counter because of his sensitivity to detect less radioactive substances and count their beta — and gamma — rays over a large area of about 100 cm2 and more. It is one of the 20th century technical devices which quickly became canonical in the field of radioactivity.
The circumstances which led to the invention are quite clear. Mueller’s task as private assistant at Geiger’s lab at the Christian Albrechts University in Kiel was to check some improvements on the point counters needle. He also applied these changes on the coaxial cylindrical device he constructed for his dissertation. By installing lead und iron plates to screen the measurement he could show, that isolated peaks, previously thought to be artifacts of the device, were actual counts of background gamma - radiation. Some details of the development of the tubecounter are unclear: Mueller and Geiger never mentioned how they installed the vacuum in the first working counters. Other physicists, e.g. Lise Meitner, had great problems to keep it stable and to operate the tubecounters over a longer period.
My research aims to bring some light in the construction process through practical experiences with the replica of an original counter from 1928.