scholarly journals Numerical Analysis of Radiation Effects on Fiber Optic Sensors

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4111
Author(s):  
Sohel Rana ◽  
Harish Subbaraman ◽  
Austin Fleming ◽  
Nirmala Kandadai
Keyword(s):  
Radiation Effects ◽  
Physical Parameters ◽  
Potential Candidate ◽  
Low Dose Radiation ◽  
Long Period Grating ◽  
Fiber Sensors ◽  
Fabry Perot ◽  
Radiation Induced ◽  
High Doses ◽  
Dose Radiation

Optical fiber sensors (OFS) are a potential candidate for monitoring physical parameters in nuclear environments. However, under an irradiation field the optical response of the OFS is modified via three primary mechanisms: (i) radiation-induced attenuation (RIA), (ii) radiation-induced emission (RIE), and (iii) radiation-induced compaction (RIC). For resonance-based sensors, RIC plays a significant role in modifying their performance characteristics. In this paper, we numerically investigate independently the effects of RIC and RIA on three types of OFS widely considered for radiation environments: fiber Bragg grating (FBG), long-period grating (LPG), and Fabry-Perot (F-P) sensors. In our RIC modeling, experimentally calculated refractive index (RI) changes due to low-dose radiation are extrapolated using a power law to calculate density changes at high doses. The changes in RI and length are subsequently calculated using the Lorentz–Lorenz relation and an established empirical equation, respectively. The effects of both the change in the RI and length contraction on OFS are modeled for both low and high doses using FIMMWAVE, a commercially available vectorial mode solver. An in-depth understanding of how radiation affects OFS may reveal various potential OFS applications in several types of radiation environments, such as nuclear reactors or in space.

scholarly journals Active Compensation of Radiation Effects on Optical Fibers for Sensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8193
Author(s):  
Sohel Rana ◽  
Austin Fleming ◽  
Nirmala Kandadai ◽  
Harish Subbaraman
Keyword(s):  
Optical Fibers ◽  
Radiation Effects ◽  
Accurate Determination ◽  
Radiation Environment ◽  
Physical Parameters ◽  
Air Cavity ◽  
Sensing Applications ◽  
Fabry Perot ◽  
Radiation Induced

Neutron and gamma irradiation is known to compact silica, resulting in macroscopic changes in refractive index (RI) and geometric structure. The change in RI and linear compaction in a radiation environment is caused by three well-known mechanisms: (i) radiation-induced attenuation (RIA), (ii) radiation-induced compaction (RIC), and (iii) radiation-induced emission (RIE). These macroscopic changes induce errors in monitoring physical parameters such as temperature, pressure, and strain in optical fiber-based sensors, which limit their application in radiation environments. We present a cascaded Fabry–Perot interferometer (FPI) technique to measure macroscopic properties, such as radiation-induced change in RI and length compaction in real time to actively account for sensor drift. The proposed cascaded FPI consists of two cavities: the first cavity is an air cavity, and the second is a silica cavity. The length compaction from the air cavity is used to deduce the RI change within the silica cavity. We utilize fast Fourier transform (FFT) algorithm and two bandpass filters for the signal extraction of each cavity. Inclusion of such a simple cascaded FPI structure will enable accurate determination of physical parameters under the test.

scholarly journals Lattice radiation therapy – its concept and impact in the immunomodulation cancer treatment era

2020 ◽  
Vol 66 (6) ◽  
pp. 728-731
Author(s):  
Antonio Cassio Assis Pellizzon
Keyword(s):  
Radiation Oncology ◽  
Dose Ratio ◽  
Low Dose Radiation ◽  
Normal Tissues ◽  
Dosimetric Characteristic ◽  
Radiation Induced ◽  
High Doses ◽  
Higher Doses ◽  
Dose Radiation

SUMMARY Voluminous tumors represent a challenge in radiation oncology, particularly when surgical resection is not possible. Lattice radiotherapy (LTR) is a technique that may provide equivalent or superior clinical response in the management of large tumors while limiting toxicity to adjacent normal tissues. LRT can precisely deliver inhomogeneous high doses of radiation to different areas within the gross tumor volumes (GTV). The dosimetric characteristic of LTR is defined by the ratio of the valley dose (lower doses – cold spots) and the peak doses, also called vertex (higher doses - hot spots), or the valley-to-peak dose ratio. The valley-to-peak ratio thereby quantifies the degree of spatial fractionation. LRT delivers high doses of radiation without exceeding the tolerance of adjacent critical structures. Radiobiological experiments support the role of radiation-induced bystander effects, vascular alterations, and immunologic interactions in areas subject to low dose radiation. The technological advancements continue to expand in Radiation Oncology, bringing new safety opportunities of treatment for bulky lesions.

Low-dose radiation-induced acute pericarditis (AP) in breast cancer patient

2013 ◽  
Vol 18 ◽  
pp. S179-S180 ◽  
Author(s):  
I. Alastuey ◽  
A. Noé ◽  
C. Chiaramello ◽  
S. Montemuiño ◽  
J. Pardo
Keyword(s):  
Breast Cancer ◽  
Cancer Patient ◽  
Breast Cancer Patient ◽  
Low Dose ◽  
Low Dose Radiation ◽  
Acute Pericarditis ◽  
Radiation Induced ◽  
Dose Radiation

scholarly journals Low-Dose Radiation-Induced Senescent Stromal Fibroblasts Render Nearby Breast Cancer Cells Radioresistant

2009 ◽  
Vol 172 (3) ◽  
pp. 306-313 ◽  
Author(s):  
Kelvin K. C. Tsai ◽  
Jeremy Stuart ◽  
Yao-Yu Eric Chuang ◽  
John B. Little ◽  
Zhi-Min Yuan
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Low Dose ◽  
Low Dose Radiation ◽  
Stromal Fibroblasts ◽  
Radiation Induced ◽  
Dose Radiation
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