Gray (unit) Gray (unit) The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed dose which measures the energy deposited in a unit mass at a certain position, and of the radiation quantity kerma, which is the amount of energy that is transferred from photons to electrons per unit mass at a certain position. The corresponding cgs unit to the gray is the rad (equivalent to
National Energy Research Scientific Computing Center and scientist Thomas Edison, which has a peak performance of 2.57 petaflop/s. Fully installed in 2014, Edison consists of 133,824 compute cores for running scientific applications, 357 terabytes of memory, and 7.56 petabytes of online disk storage with a peak I/O bandwidth of 168 gigabytes (GB) per second. Other systems at NERSC include: NERSC facilities are accessible through the Energy Sciences Network, or ESnet, which is also managed by Lawrence Berkeley National Laboratory for the Department of Energy. NERSC staff are leading a number of special projects to advance computational science while also helping prepare the broader research community for