NSUF 22-4378: Radiation-induced Attenuation and Nonlinear Optical Properties of Fused Silica and Single-crystal Sapphire
Linear optical transmission will be measured using an existing broadband measurement system at ORNL and cross-checked with the mobile post-irradiation examination system provided by the University of Michigan (UM). The mobile system provided by UM will be used to measure the nonlinear refraction and absorption using the nanosecond Z-Scan technique. The UM system has been recently developed as a part of an active NSUF-supported R&D program and successfully operated at the Ohio State University’s NSUF facility. For the measurement of samples that experience significant activation, the UM system will be temporarily deployed at the NSUF facility at ORNL. Dimensional measurements will be performed on all samples to determine radiation-induced dimensional changes, which cause drift in some fiber optic-based sensors that rely on dimensional changes in the fiber materials to measure temperature or strain. Dilatometry will also be performed on half of the optical samples to provide in-situ measurements of radiation-induced dimensional changes at various annealing temperatures and further inform models for predicting radiation-induced drift in fiber optic sensors composed of these materials. The remaining optical samples will be subjected to isochronal annealing followed by optical transmission measurements to determine the effect of post-irradiation annealing on the optical properties. We will require 9 months to make the measurements, all on irradiated samples. For α-Al2O3, which could enable higher temperature operation, existing results show high radiation-induced attenuation (RIA) that increases significantly with increasing temperature, which contrasts with previous in-situ measurements performed at low neutron flux (~1011 to 1012 n/cm2/s) and fluence (~1016 n/cm2). This RTE will reveal dimensional changes when samples are irradiated to much higher neutron fluence. The scientific outcome of these experiments will be trifold. Firstly, it will be determined whether RIA and signal drift in a-SiO2 reach equilibrium and remain tolerable, enabling the continuation of R&D for the in-pile application of fiber optic sensors. Secondly, the RIA increase in α- Al2O3 irradiated to a higher neutron fluence (~1022 n/cm2), will answer the question of whether the α- Al2O3 can be used as an optical material for high temperature, high dose applications. Finally, the radiation-induced changes of nonlinear optical properties of these materials will be unveiled. This is important not only from the standpoint of improved fundamental understanding and validation of the existing models but also for sensor applications that require propagation of high-peak-power laser radiation.
Additional Info
| Field | Value |
|---|---|
| Abstract | Linear optical transmission will be measured using an existing broadband measurement system at ORNL and cross-checked with the mobile post-irradiation examination system provided by the University of Michigan (UM). The mobile system provided by UM will be used to measure the nonlinear refraction and absorption using the nanosecond Z-Scan technique. The UM system has been recently developed as a part of an active NSUF-supported R&D program and successfully operated at the Ohio State University’s NSUF facility. For the measurement of samples that experience significant activation, the UM system will be temporarily deployed at the NSUF facility at ORNL. Dimensional measurements will be performed on all samples to determine radiation-induced dimensional changes, which cause drift in some fiber optic-based sensors that rely on dimensional changes in the fiber materials to measure temperature or strain. Dilatometry will also be performed on half of the optical samples to provide in-situ measurements of radiation-induced dimensional changes at various annealing temperatures and further inform models for predicting radiation-induced drift in fiber optic sensors composed of these materials. The remaining optical samples will be subjected to isochronal annealing followed by optical transmission measurements to determine the effect of post-irradiation annealing on the optical properties. We will require 9 months to make the measurements, all on irradiated samples. For α-Al2O3, which could enable higher temperature operation, existing results show high radiation-induced attenuation (RIA) that increases significantly with increasing temperature, which contrasts with previous in-situ measurements performed at low neutron flux (~1011 to 1012 n/cm2/s) and fluence (~1016 n/cm2). This RTE will reveal dimensional changes when samples are irradiated to much higher neutron fluence. The scientific outcome of these experiments will be trifold. Firstly, it will be determined whether RIA and signal drift in a-SiO2 reach equilibrium and remain tolerable, enabling the continuation of R&D for the in-pile application of fiber optic sensors. Secondly, the RIA increase in α- Al2O3 irradiated to a higher neutron fluence (~1022 n/cm2), will answer the question of whether the α- Al2O3 can be used as an optical material for high temperature, high dose applications. Finally, the radiation-induced changes of nonlinear optical properties of these materials will be unveiled. This is important not only from the standpoint of improved fundamental understanding and validation of the existing models but also for sensor applications that require propagation of high-peak-power laser radiation. |
| Award Announced Date | 2022-06-14T07:27:41.97 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kory Linton |
| Irradiation Facility | None |
| PI | Milos Burger |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4378 |