Characterization of Lab-on-Fiber-based dosimeters in ultra-high dose radiation fields. (June 2023)

• Record Type: Journal Article
• Authors: Vaiano, Patrizio; Quero, Giuseppe; Fienga, Francesco; Di Meo, Valentina; Casolaro, Pierluigi; Campajola, Luigi; Breglio, Giovanni; Crescitelli, Alessio; Esposito, Emanuela; Cutolo, Antonello; Ravotti, Federico; Buontempo, Salvatore; Consales, Marco; Cusano, Andrea
• Is Part Of: Optics & laser technology. Volume 161(2023)
• Publication Date: 2023-06
• Subjects: Lab-On-Fiber -- X-rays -- PMMA -- Optical fiber -- Dosimetry -- Plasmonics; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2023.109177
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: An innovative Lab-On-Fiber probe for the real-time dose monitoring was developed. The exposure to ∼ 2 MGy X-rays led to a reduction of the PMMA thickness (26–40 %). PMMA compaction was observed for ultra-high doses of X-rays, electrons and protons. The absorbed dose is the main parameter affecting the PMMA relative compaction. Abstract: Next generation High Energy Physics (HEP) accelerators will require new devices and technologies capable of operating in extreme environments characterized by ultra-high radiation doses up to the MGy levels. To this aim, we report on an innovative Lab-On-Fiber (LOF) probe for the real-time dose monitoring. The proposed platform is based on a metallo-dielectric nanostructured grating made of gold and poly(methyl methacrylate) (PMMA) patterned on the termination of single mode fibers. The nanostructure has been judiciously designed to support a plasmonic resonance in the reflection spectrum occurring at near infrared wavelengths. Electron beam lithography was used for the fabrication of two LOF prototypes, which in turn, were exposed to X-rays with a total dose of 2.02 MGy and a dose rate of 88 kGy/h. Reflection spectra acquired during the irradiation revealed a clear dependence of the LOF resonance wavelength and depth on the absorbed dose, confirming the outcomes of our previous proton campaign. Morphological characterization of the irradiated samples showed that the main radiation induced effect is the reduction of the PMMA thickness (ranging between 26 % and 40 %), which in turn strongly affects the resonance behavior. Quantitative morphological measurements have been used to achieve a fair and objective correlation with our numerical modelling. Moreover, we investigated the effect of ultra-high doses of several radiation types, including X-rays, electrons and protons, on the thickness of PMMA nanolayers deposited on planar substrates. Experimental results revealed that the amount of absorbed dose (1.9–16.06 MGy) is the main parameter affecting the PMMA relative compaction (9.5–59.1 %), while the influence of the radiation type, dose rate and initial PMMA thickness can be considered negligible. Overall, these results pave the way to the development of radiation type independent PMMA assisted LOF dosimeters operating at MGy doses for the radiation monitoring in future HEP experiments.