Demountable type IG20 Geiger-Muller tube
1968
1968
1950-78
1950-60
1978-95
1960-78
1992
1950-78
1960-78
1953-78
1948-78
1959
1950-1983
1956-1985
1950-1983
1978-95
1978-1995
1996
1995
1948-78
1960-78
1960-70
1950-1980
1960-1981
1951-1978
1978-95
1963
1960
1958-78
1965
Coincidence Unit 1036C: 1957; Geiger-Muller tubes: 1956-1961; Probe Units Type N558: 1955-1961
1950-60