{"type": "FeatureCollection", "features": [{"id": "10.1117/12.2624440", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:18:07Z", "type": "Journal Article", "created": "2022-05-19", "title": "Perfluorinated polymer fibre Bragg grating sensors for distributed low-dose clinical X-ray measurements", "description": "Optical fibres have played an important role in the advancement of real-time dosimetry in clinical applications in recent years. Significant work has been done to increase precision and accuracy in detecting radiation doses during treatment, to avoid the negative effect that can ensue from irradiating healthy tissue around the tumour. The drive to develop distributed measurement in optical fibres has been limited to the slow scanning speed systems from optical time domain reflectometry (OTDR), however for radiotherapy dosimetry, with often short radiation pulse durations, fibre Bragg grating (FBG) interrogation is a better alternative because of the fast-scanning speed. The work presented here includes the preliminary results in the characterisation of CYTOP FBGs on exposure to X-ray radiation emitted from a clinical linear accelerator (linac) machine. A blue shifted linear response of the Bragg wavelength with sensitivity of 6.655 pm/Gy, 6.519 pm/Gy and 7.153 pm/Gy at the three main peaks (1522 nm, 1542 and 1561 nm), was recorded for a 9 Gy of radiation at a dose rate of 1.758 Gy/min with an amplitude fluctuation within the duration of radiation. The response demonstrates the potential for its use in low dose radiation dosimetry, providing for quasi-distributed sensing in radiotherapy.", "keywords": ["0211 other engineering and technologies", "fibre optics dosimetry", "02 engineering and technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "X-ray", "Fibre Bragg grating", "Optical fibres", "Radiation Monitoring", "Dosimetry", "fibre Bragg grating sensors", "0202 electrical engineering", " electronic engineering", " information engineering", "fibre optics sensors", "Engineering and Technology", "CYTOP", "low-dose clinical X-ray measurements"]}, "links": [{"href": "https://doi.org/10.1117/12.2624440"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Micro-Structured%20and%20Specialty%20Optical%20Fibres%20VII", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2624440", "name": "item", "description": "10.1117/12.2624440", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2624440"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-19T00:00:00Z"}}, {"id": "10.1117/12.2624501", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:18:07Z", "type": "Journal Article", "created": "2022-05-19", "title": "Pre-strain effects on CYTOP fibre Bragg grating temperature sensors", "description": "Cyclic transparent optical polymer (CYTOP) based fibre Bragg grating (FBG) sensors are of high interest recently due to their lower optical loss compared with the sensors fabricated in other polymeric materials, such as poly(methyl methacrylate). Numerous scientific reports have shown that polymer based FBGs are usually preferred over their silica counterparts due to their enhanced sensitivity to stress and pressure, and their affinity to humidity. Temperature monitoring with polymer FBGs is also extensively demonstrated, but with inconsistent results and non-linear responses, since most of the polymer optical fibres have a negative thermo-optic coefficient and positive thermal expansion coefficient that work to cancel out each other to some extent, resulting in mixed temperature sensitivities. In this work, an optical fibre with a CYTOP core and a Xylex cladding is used to investigate fibre pre-strain effects on the temperature sensitivity of FBG sensors. The sensors were placed in an environmental chamber with controlled temperature and relative humidity, and their response to temperature was evaluated under various fibre pre-strain values. Without any applied fibre strain, the thermal expansion coefficient slightly prevails over the thermo-optic effect, as a result the Bragg wavelength shifts in longer wavelengths. Under sufficient fibre strain, the thermal expansion coefficient is eliminated, and the temperature sensitivity is greatly enhanced, shifting the Bragg wavelength to shorter wavelengths. This paper demonstrates the possibility to have an array of Bragg grating sensors, some being temperature insensitive and some highly temperature sensitive along the same fibre.", "keywords": ["polymer optical fibre", "optical polymer", "fibre Bragg grating sensors", "0103 physical sciences", "Bragg gratings", "Engineering and Technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "01 natural sciences", "temperature sensing"], "contacts": [{"organization": "Pospori, Andreas, Ioannou, Andreas, Kalli, Kyriacos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1117/12.2624501"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Micro-Structured%20and%20Specialty%20Optical%20Fibres%20VII", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2624501", "name": "item", "description": "10.1117/12.2624501", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2624501"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-19T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=fibre+Bragg+grating+sensors&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=fibre+Bragg+grating+sensors&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=fibre+Bragg+grating+sensors&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=fibre+Bragg+grating+sensors&offset=2", "hreflang": "en-US"}], "numberMatched": 2, "numberReturned": 2, "distributedFeatures": [], "timeStamp": "2026-09-22T22:54:26.479231Z"}