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
Abraham Roentgen he established a furniture manufactory. Upon his retirement in 1772 his son David took over the business and established his own reputation. Abraham Roentgen died in Herrnhut in Saxony Germany in 1793. Abraham Roentgen Abraham Roentgen (30 January 1711 – 1 March 1793) was a German Ébéniste (cabinetmaker). Roentgen was born in Mülheim am Rhein, Germany. He learned cabinet making from his father. At age 20, he traveled to Den Haag, Rotterdam and Amsterdam, learning from established cabinet makers. He became known for his marquetry work, and worked in London (in the workshop of William Gomm) until 1738. On 18