Roentgen (unit) Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays. It is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air. In 1928 it was the first international measurement quantity for ionising radiation to be defined for radiation protection, and was an easily replicated method of measuring air ionization directly by using an ion chamber. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays. Although relatively easy to measure, it had
David Roentgen Gotha, exhibited at Callenberg Castle in Coburg, north Bavaria. In 2012 Wolfam Koepp of the Metropolitan Museum of Art discovered a particular type of Roentgen table with removable legs for easier transport. Was this table the earliest form of flatpack? A team from the Victoria and Albert Museum investigated further and confirmed Koepp's process and conclusions in March 2014, shedding new light on the inventor of flat-pack / ready-to-assemble furniture. Until then, Gillis Lundgren held that title from 1951 for IKEA. Its blame has now been traced back 200 years before the pretender. David Roentgen not only mastered intrigue but