IEEE Standards on Gas-Filled Radiation Counter Tubes: Methods of Testing, 1952

In setting up test procedures for radiation counter tubes, it is necessary to consider not only the test circuits but also the physical arrangements of test, such as nature of source, distance between source and counter, scattering by objects near the source or counter, shielding of the counter against unwanted radiations, and the background due to cosmic rays and general contamination. The relative importance of these various factors will depend on the type of counter under test