A method comprising irradiating a layer of lignocellulosic material with a series of doses of radiation, using more than one electron beam device, to deliver to the lignocellulosic material a total dose of radiation of at least 10 Mrad at a dose rate of from about 1 Mrad/s to 10 Mrad/s； cooling the irradiated lignocellulosic material using a heat exchange system comprising one or more heat exchangers after irradiating with each electron beam device； and hydrolyzing the irradiated and cooled material with an enzyme or microorganism to produce sugars, wherein during irradiating substantially none of the lignocellulosic material is wetted with a liquid.
