Description: Gas proportional radiation counting tube.

Caption: This is one of the first of the Maze type of Geiger-Muller counting tubes made with a bubble window. It was probably used to test differing mixes of gases. Early tubes were filled with an argon-alcohol mix. The stopcock was used for pumping down and refilling the tube typically at a pressure of 10-11 cm of mercury. The anode is tungsten and the cathode is in the form of a water based carbon coating called aquadag.

Introduction: Often simply called a Geiger counter, this instrument is named for the designers of the first radiation counter, the German Physicists, Hans Wilhelm Geiger and Walther Muller. R. Maze discovered in 1946 that the metal tube cathodes of the earlier counters could be replaced by thin glass covered with aquadag, a water-based graphite coating. This tube has an external aquadag coating.

Background: This experimental tube was made at Glasgow University by John Lloyd, in the Department of Natural Philosophy in about 1947. John Lloyd invented the bubble window process for counters designed by Samuel Curran.

Reference: Lloyd, John, Travers. "Journal of Scientific Instruments", vol 26, 1949, p. 126

Reference: Curran, Samuel Crowe and Craggs, John Drummond. "Counting Tubes Theory and Applications", 1949

Historical Context: Design of the counting tube - Who: Curran, Samuel Crowe, Professor, later Sir (1912-1998) Physicist and first principal of Glasgow's Strathclyde University

Historical Context: Design of the counting tube by Curran - When: 1947

Historical Context: Design of the counting tube by Curran, Kelvin Building, University of Glasgow - Where: University Avenue, Glasgow, Scotland

Historical Context: Design of the Geiger-Muller counting tube - Who: Muller, Walther, Professor - Who: Geiger, Hans Wilhelm (1882-1945)

Historical Context: Discovery of the photovoltaic effect by Becquerel - When: 1839 - Where: Paris, France - Who: Becquerel, Alexander Edmond (1820-1891) French physicist and chemist

Historical Context: Invention of the bubble window process - Who: Lloyd, John (Jack) Travers (fl.1948-1981)

Historical Context: Invention of the bubble window process by John Lloyd, Kelvin Building, University of Glasgow - Where: University Avenue, Glasgow, Scotland

Historical Context: Invention of the bubble window process by Lloyd - When: 1947

Historical Context: Invention of the counting tube - Who: Rutherford, Ernest, 1st Baron Rutherford of Nelson (1871-1937) New Zealand born physicist

Historical Context: Invention of the counting tube by Rutherford and Geiger - When: 1908 - Where: Manchester, England

Historical Context: Invention of the gas proportional radiation counting tube by Geiger and Muller - When: 1928

Historical Context: Invention of the gas proportional radiation counting tube by Geiger and Muller, Keil University - Where: Germany

Historical Context: Manufacture - Who: Lloyd, John (Jack) Travers (fl.1948-1981)

Historical Context: Manufacture by Jack Lloyd - When: 1947

Historical Context: Manufacture of the tube by John Lloyd, Kelvin Building, University of Glasgow - Where: University Avenue, Glasgow, Scotland

Historical Context: Use of a self quenching polyatomic gas in counting tubes - Who: A. Z. Tost

Historical Context: Use of a self quenching polyatomic gas in counting tubes by Tost - When: 1935 - Where: Germany

Historical Context: Use of aquadag as a cathode by Maze - When: 1946

Historical Context: Use of aquadag coating as a cathode in counting tubes - Who: Professor Roland Maze, French Physicist who independently discovered cosmic rays in 1938

Historical Context: Use of auadag as a cathode by Maze, Paris Ecole Normale Superieure - Where: France