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
The Invention of the Jewish People The Invention of the Jewish People The Invention of the Jewish People (, literally "When and How Was the Jewish People Invented?") is a study of the historiography of the Jewish people by Shlomo Sand, Professor of History at Tel Aviv University. It has generated a heated controversy. The book was in the best-seller list in Israel for nineteen weeks. An English translation of the book was published by Verso Books in October 2009. The book has also been translated into German, Italian, Spanish, Portuguese, Arabic, French and Russian, and as of late 2009 further translations were underway. "The Invention