Depth-resolved dose estimation in cellulose via pyrolysis for low-energy electron-beam processing

Abstract We propose a new method for estimating dose distribution in cellulose-based materials exposed to electron beams. The technique leverages the dose-dependent pyrolysis behavior of cellulose to directly quantify the absorbed dose. Using this method, we successfully estimated the absorbed dose not only in pure cellulose but also in natural cotton fibers and paper-based materials (e.g., laboratory wipes) that contain non-cellulosic impurities. Our thermogravimetry-based approach enables the highly reproducible dose estimation in samples as little as a few milligrams, yielding vertical dose distribution within extremely narrow regions (several tens of micrometers). Because of the fibrous morphology of cellulose-based materials, predicting electron-beam penetration depth in these materials is more difficult than in polymer films. However, the proposed method enables the straightforward determination of the penetration depth corresponding to each acceleration voltage. Therefore, it is expected to become a valuable tool for optimizing irradiation conditions in the production of cellulose-based grafted fibers using low-energy accelerators.