Investigation of UV optical fibers under synchrotron irradiation

Abstract

Abstract:The focus of the present paper deals, for the first time, with commercial UV optical fibers, characterizing their behaviour as they are subjected to very high flux wiggler generated synchrotron radiation. Five distinct types of UV optical fibers, produced by three manufactures, were exposed to total doses between 5 Gy and 2000 Gy. The exposure to synchrotron radiation was performed in two campaigns. The tests were run off-line and considered the dependence of the radiation induced attenuation (RIA) as function of the total dose. The recovery of the radiation induced colour centres was studied at room temperature and after heating the samples up to 560 K. As a première, we also investigated through THz imaging and spectroscopy the irradiated optical fiber samples. Under these conditions, three of the optical fibers proved to be radiation resistant. The two optical fibers sensitive to synchrotron radiation exhibited a linear variation of the optical absorption at the wavelengths of λ = 229 nm, λ = 248 nm, and λ = 265 nm, for total doses between 60 Gy and 2000 Gy. These two samples showed also an increase of the optical absorption in the UV spectral range when heated to 560 K. The optical fibers sensitive to synchrotron radiation can potentially be used for on-line radiation dosimetry. ©2014 Optical Society of America

Fully Dehydroxylated Silica Generated from Hydrosilane: Surface Defects and Reactivity

“…Figure a shows the UV–vis spectrum of 1 – 900 , which exhibits two distinct maxima at 220 and 248 nm, consistent with π–π* or n−π* transitions (details in Figure b). − Exposure to air for 15 s decreases: (a) the intensity of the two peaks likely due to the reaction of the respective centers with oxygen and water and (b) the signal intensity in the region between 400 and 600 nm. The first site with an absorption maximum at 251 nm resembles oxygen-deficient centers of the second type (ODC II), which are typically associated with silylene sites. ,− The second peak has parameters with values between those typical of E’ sites and ODC­(II), and can, therefore, be associated either with paramagnetic silicon defects or with distorted silylenes. ,, Part of the broad shoulder might originate from another transition belonging to ODC­(II), expected at 393 nm; however, the formation of a similar shoulder is also observed in the spectra of irradiated silicas. , The spectrum of 1 – 700 looks very similar to 1 – 900 , suggesting the presence of similar defects, while spectra of 1 – 150 and 1 – 500 do not show any absorption bands (Figure S5).…”

Medical physics aspects of the synchrotron radiation therapies: Microbeam radiation therapy (MRT) and synchrotron stereotactic radiotherapy (SSRT)

“…Under these conditions, three of the optical fibers proved to be radiation hardened, while two of them were sensitive to synchrotron radiation exposure. All the optical fibers showed a recovery of the optical absorption after storage for 10 days at room temperature [46]. A special setup was developed to monitor the dynamics of the color centers in the UV spectral range (Fig.…”

A radiation–temperature coupling model of the optical fiber attenuation spectrum in the Ge/P co-doped fiber

“…[4,5] The RIA in optical fibers has been extensively studied. [6][7][8][9][10][11] During the past decades and a number of papers have treated the modeling of RIA with the irradiation dose at a single wavelength during irradiation and recovery after irradiation. The power-law model, the stretched saturating exponential model, and the saturating exponentials model have been proposed by different authors.…”