Roentgen (unit) absorbed dose in a wide range of matter. When measuring absorbed dose in a human due to external exposure, the SI unit the gray, or the related non-SI rad are used. From these can be developed the dose equivalents to consider biological effects from differing radiation types and target materials. These are equivalent dose, and effective dose for which the SI unit sievert or the non-SI rem are used. The following table shows radiation quantities in SI and non-SI units: Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays
David Roentgen soared far above him. As an adroit devisor of mechanism he fully earned a reputation which former generations rated more highly than the modern critic, with his facilities for comparison, is prepared to accept. On the mechanical side he produced, with the help of Kintzing, many long-cased and other clocks with ingenious indicating and registering apparatus. Roentgen delighted in architectural forms, and his marquetry more often than not represents those scenes from classical mythology which were the dear delight of the 18th century." He is well represented at the V&A Museum in London, and other collections. David Roentgen David Roentgen