TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The method further comprises: conveying the biomass material through the first opening, positioning the biomass material under the secondary single-type window foil and irradiating the biomass material; conveying the treated biomass material out of the treatment enclosure through the second opening; and purging the treatment enclosure with an inert gas or a reactive gas. The biomass (444) is treated with 10-200 (preferably 30-35) Mrad of radiation. Preferred Components: The starting biomass material is cellulosic material, lignocellulosic material or starchy material. The biomass is paper, paper products, paper waste, wood, particle board, sawdust, agricultural waste, sewage, silage, grasses, wheat straw, rice hulls, bagasse, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs, corn stover, alfalfa, hay, coconut hair, seaweed and/or algae.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: At least one of the windows is in the form of a metallic foil. The multiple window foils comprise a system of gas cooled window foils in which a primary single-type window foil communicates with a high vacuum side of a scanning horn of an electron beam accelerator and a secondary single-type window foil is positioned on an atmospheric side of the scanning horn. The system of gas cooled window foils define a gap between the primary and secondary window and a first flow path provides cooling to the primary window foil and a second flow path provides cooling to the secondary window foil. The system of gas cooled window foils further comprises, both the primary window foil and the secondary window foil are part of the scanning horn of the electron beam accelerator, where at least one inlet (516), which allows a cooling gas to enter the gap defined between the primary and the secondary window and at least one outlet (514), to extract cooling gases from the gap defined between the primary and secondary window. The cooling chamber comprises four walls and the interior volume is rectangular prism in shape. The system further comprises a treatment enclosure with a cover surface, where the enclosure is positioned on a side of the secondary single-type window foil opposite the electron beam accelerator. The secondary single-type window foil is mounted on the cover surface and is integral to the treatment enclosure. The cover surface is perpendicular to the electron beam accelerator. The treatment enclosure has a first opening. The treatment enclosure comprises a second opening. The primary single-type window foil is made from an element consisting of titanium, scandium, vanadium, chromium, nickel, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, hafnium, tantalum, tungsten, rhenium, platinum, iridium, and/or their alloys. The secondary single-type window foil is made from an element consisting of titanium, scandium, vanadium, chromium, nickel, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, hafnium, tantalum, tungsten, rhenium, platinum, iridium, beryllium, aluminum, silicon, and/or their alloys. The primary single-type window foil and the secondary single-type window foil are made of the same element or different elements, and/or alloys. The primary single-type window foil or the secondary single-type window foil or both are made from a low energy (Z) element. The primary single-type window foil is made from a high Z element and the secondary single-type window foil is made from a low Z element. The primary single-type window foil is 10-50 (preferably 20-30) mu m thick. The secondary single-type window foil is 5-30 (preferably 10-20) mu m thick. The primary single-type window foils are the same thickness or different thicknesses. The electron beam comprises electrons having an energy of 0.5-10 (preferably 1) MeV. The electron beam has a beam current of at least 50 mA, preferably 150 mA. The method further comprises a beam stop. The electron beam comprises electrons having an energy of 1 MeV, and the spacing between the primary single-type window foil and the secondary single-type window foil is less than 30 (preferably 10) cm, or the electron beam comprises electrons having an energy of 5 MeV, and the spacing between the primary single-type window foil and the secondary single-type window foil is less than 75 (preferably 20) cm. The beam stop is moveable to absorb different amounts of the electron beam. The beam stop absorbs at least 20%, preferably 80% of the incident electrons. EXAMPLE - No suitable example given.