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2 2024

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Liquid dosimeter with sensitivity in low-kGy range for the characterization of a new module for EB wastewater treatment

Schaap Lotte Ligaya, Teichmann Tobias, Poremba Andre, Besecke Joana Kira, Schopf Simone, Mattausch Gösta, Hauff Elizabeth von

Nukleonika

2024

Vol. 69, No. 2

75--80

In recent years, the use of low-energy electrons in various ecological and biotechnological applications has become increasingly relevant. One important application is the treatment of wastewater, wherein highly reactive species produced by water irradiation are used to oxidize pollutants. Low-energy electron irradiation has several advantages, such as minimal demands on radiation protection and electron beam (EB) source dimensions. However, to play into the main advantages of this technology and keep it economically viable, it is necessary to keep the absorbed dose as low as possible. This calls for a liquid dosimeter with sensitivity in the single digit kGy range. An extract from natural Hibiscus sabdariffa (Roselle) has been reported to show a radiochromic effect in this dose range. In the present work, Roselle dosimeter solutions were closely investigated and optimized to characterize a new module for EB wastewater treatment. Upon EB irradiation, the dosimeter solution demonstrated a dose-dependent fading in color, making it useful in the 0.3–7.5 kGy dose range.

Dosimetry for low-energy electron beam applications at Fraunhofer FEP

Teichmann Tobias, Schaap Lotte Ligaya, Poremba Andre, Dincklage Lars, Blüthner Ralf, Sommer Marian, Henniger Jürgen, Schopf Simone, König Ulla, Mattausch Gösta

Nukleonika

2024

Vol. 69, No. 2

81--85

Accelerating electrons to achieve chemical and biological effects is a well-established competence of Fraunhofer FEP. Today, there is a large variety of low-energy electron beam applications with a broad range of absorbed doses, e.g. modification of plastics, plasma-chemical syntheses, pollutant removal in wastewaters and exhaust gases, sterilization of medical products, disinfection of seeds, biocompatible functionalization of implants and stimulation of biotechnological processes. This calls for reliable, sensitive, and flexible methods for dosimetry. Radiochromic fi lms are suitable tools to measure electron dose distributions for the characterization and quality control of Fraunhofer FEP’s irradiation facilities. Risø B3 radiochromic film from DTU Health Tech, the dosimeter of choice at FEP, reliably detects doses in the range of 10–100 kGy. However, with new upcoming applications, doses in the single-digit kGy range and even lower come to the fore. Hence, the palette of dosimeters at FEP must be extended. Gafchromic’s HD-V2 fi lm is a welcome complement and widens the accessible dose range down to 10 Gy. Using a UV-VIS spectrophotometer for read-out of the fi lms and custom analysis algorithms further increase the sensitivity of the dosimetric setup. Additionally, dosimeters based on the optically stimulated luminescence (OSL) of beryllium oxide offer a wide dose range and high sensitivity. They were used to measure doses induced by secondary X-ray components to gain more information about a specific radiation field. The work gives an overview of the dosimetric toolbox at Fraunhofer FEP and the efforts to implement new methods of detection for low-dose applications and X-ray dosimetry.