Ionization chamber with double input window for measuring X-ray exposure

摘要

A dual entrance window ion chamber (10) is surrounded by a housing (50) with 1st and 2nd openings (54,56) covered by 1st and 2nd X-ray windows (120,122) on opposite sides of the chamber (10). A collector (100) in the chamber between the 2 windows collects electrons for use in measuring X-ray exposure. The 1st window (120) has its construction optimised to provide a relatively flat energy response to X-rays over a 1st energy range whilst the 2nd window (122) is so constructed to provide a flat response over a 2nd and greater energy level.