Ivan Puluj in the UK. While Professor Puluj's finding were essentially X-rays, he did not recognise them as such at first, although he demonstrated X-ray pictures of a hand and fingers obtained by using his tube / lamp to his students. This credit later went on to Wilhelm Conrad Röntgen. Once Roentgen visited Professor Puluj's laboratory and the latter presented one of his tubes to Roentgen. Roentgen went home and in his laboratory started to conduct experiments with Puluj's tube. Puluj also continued to do research with his X-ray tubes. On 8 February 1896, just 6 weeks after Röntgen presented his finding
Roentgen (unit) In radiation protection the absorbed dose is the energy absorption which is an indication of likely acute tissue effects occurring at high dose rates, and from low levels of absorbed dose the equivalent dose, representing the stochastic health risk, can be calculated; for which the current SI units used are the gray (Gy) and the sievert (Sv) respectively. The roengten has been redefined over the years. It was last defined by the US National Institute of Standards and Technology (NIST) in 1998 as , with a recommendation that the definition be given in every document where the roentgen is used.