Development Of Optical Diagnostics Research Articles

Role of the Neutron Calculations in the Development of Optical Diagnostics in ITER

Role of the Neutron Calculations in the Development of Optical Diagnostics in ITER

Measurement of Optical Properties of Human Gums and Dentin in the Spectral Range from 350 to 800 nm

Knowledge of the optical properties of biological tissues is important for the development of optical diagnostics, photodynamic and photothermal therapy of various diseases. However, despite the significant number of works devoted to the determination of the optical properties of tissues, the optical properties of human gums and dentin remain currently poorly understood. In this work, we experimentally studied the optical properties of human gums and dentin in the spectral range from 350 nm to 800 nm. Basing on measured diffuse reflection and total transmission spectra and using the Inverse Adding Doubling (IAD) method, the spectral dependences of absorption and scattering coefficients of the studied tissue samples were calculated.

Engineering aspects of a fully mirrored endoscope

The development of optical diagnostics, like endoscopes, compatible with the ITER environment (metallic plasma facing components, neutron proof optics, etc.) is a challenge, but current tokamaks such as JET provide opportunities to test fully working concepts. This paper describes the engineering aspects of a fully mirrored endoscope that has recently been designed, procured and installed on JET. The system must operate in a very strict environment with high temperature, high magnetic fields up to B=4T and rapid field variations (∂B/∂t∼100T/s) that induce high stresses due to eddy currents in the front mirror assembly. It must be designed to withstand high mechanical loads especially during disruptions, which lead to acceleration of about 7g at 14Hz. For the JET endoscope, when the plasma thermal loading, direct and indirect, was added to the assumed disruption loads, the reserve factor, defined as a ratio of yield strength over summed up von Mises stresses, was close to 1 for the mirror components. To ensure reliable operation, several analyses were performed to evaluate the thermo-mechanical performance of the endoscope and a final validation was obtained from mechanical and thermal tests, before the system's final installation in May 2011. During the tests, stability of the field of view angle variation was kept below 1° despite the high thermal gradient on endoscope head (∂T/∂x∼500K/m). In parallel, to ensure long time operation and to prevent undesirable performance degradation, a shutter system was also implemented in order to reduce impurity deposition on in-vessel mirrors but also to allow in situ transmission calibration. One of the main specifications of the shutter system was high reliability. This was considered as achieved when the prototype was successfully tested to 3000 cycles at a temperature of 300°C.

Optical Diagnostics of Pain Targets during Laparoscopic Surgery

The causes of uterine pain are poorly understood and the development of optical diagnostics provides an opportunity to improve surgical outcomes. One hypothesis is that some conditions manifest with ischemia and others via inflammation with elevated perfusion. Our own preliminary animal models support the concept that different types of pain result in divergent effects on uterine perfusion and oxygenation. The objective of this study is to evaluate the significance of uterine oxygenation/perfusion and feasibility of optical monitoring adapted to laparoscopic cameras.