Roentgen (unit) this derivative quantity the roentgen equivalent physical (rep) to distinguish it from the ICR roentgen. The introduction of the roentgen measurement unit, which relied upon measuring the ionisation of air, replaced earlier less accurate practices that relied on timed exposure, film exposure, or fluorescence. This led the way to setting exposure limits,and the National Council on Radiation Protection and Measurements of the United States established the first formal dose limit in 1931 as 0.1 roentgen per day. The International X-ray and Radium Protection Committee, now known as the International Commission on Radiological Protection (ICRP) soon followed with a limit of
Wilhelm Stier - 1999, Professor at the Techical University of Graz, Austria Wilhelm Stier - Familytree - Family member. Wilhelm Stier Wilhelm Stier (born May 8, 1799 in Błonie near Warsaw, died September 19, 1856 in Schöneberg, full name: Friedrich Ludwig Wilhelm Stier) was a German architect and university teacher at the Berlin Bauakademie. Wilhelm Stier was born the son of Christiane Eleonora Stiers 1766 - & Friedrich Ludewik Stier 1765 - 1815 a German postmaster & taxman in the then Prussian province of South Prussia & then Wilhelms family moved to Silesia. Wilhelm Stier was Grand son to Medical Officer /