ABSTRACT
The visible TV system used in the Korea Superconducting Tokamak Advanced Research device has been equipped with a periscope to minimize the damage on its CCD pixels from neutron radiation. The periscope with more than 2.3 m in overall length has been designed for the visible camera system with its semi-diagonal field of view as wide as 30° and its effective focal length as short as 5.57 mm. The design performance of the periscope includes the modulation transfer function greater than 0.25 at 68 cycles/mm with low distortion. The installed periscope system has confirmed the image qualities as designed and also as comparable as those from its predecessor but with far less probabilities of neutral damages on the camera.
ABSTRACT
We present a general Stokes interferometer/polarimeter suitable for polarimetric imaging the elliptically polarized motional Stark-Zeeman multiplet. We also introduce a fully phase-heterodyne spatial multiplex variant of the system that has been used for imaging of Balmer alpha emission from the heating neutral beam in the KSTAR super-conducting tokamak in Korea. The polarimeter performance is illustrated using various polarization test targets.
ABSTRACT
To monitor the global formation of the initial plasma and damage to the internal structures of the vacuum vessel, an in-vessel visible inspection system has been installed and operated on the Korean superconducting tokamak advanced research (KSTAR) device. It consists of four inspection illuminators and two visible/H-alpha TV cameras. Each illuminator uses four 150 W metal-halide lamps with separate lamp controllers, and programmable progressive scan charge-coupled device cameras with 1004 x 1004 resolution at 48 framess and a resolution of 640 x 480 at 210 framess are used to capture images. In order to provide vessel inspection capability under any operation condition, the lamps and cameras are fully controlled from the main control room and protected by shutters from deposits during plasma operation. In this paper, we describe the design and operation results of the visible inspection system with the images of the KSTAR Ohmic discharges during the first plasma campaign.
ABSTRACT
Visible camera technologies have made remarkable progress in recent years, and the fast camera has proven itself to be a capable imaging diagnostic in studies of specific fusion plasma issues such as the start-up physics, plasma wall interactions, edge-localized modes, and disruptions. For the purpose of favorable visible imaging, a fast framing camera has recently been installed on the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The camera uses a complementary metal-oxide semiconductor detector with a maximum resolution of 1280x1024 at 1000 frames/s (fps) and a minimum resolution of 1280x16 at 64 kfps. A 2-m-long viewport having a novel optical rail system was installed on a tangential port to view the tokamak interior. The system is fully controlled from the main control room and protected by a shutter from deposits. To verify that the camera electronics are safe from the high magnetic field and its rapid time variation, possible influences are considered theoretically and experimentally. In this work, we present the design and installation of the fast camera system on the KSTAR device with discussions on the field variation effect issues.
ABSTRACT
PHACE syndrome is a neurocutaneous syndrome with the following features: posterior fossa malformations of the brain, large facial hemangiomas, arterial anomalies, cardiac anomalies and aortic coarctation, and eye abnormalities. We report a rare case of bilateral internal carotid artery agenesis with transcranial collaterals from the external carotid arteries and agenesis of the vertebrobasilar system in a possible PHACE syndrome. We suggest that the patient had an incomplete phenotypic expression of the PHACE syndrome. Although the phenotypic spectrum is broad and is still largely unexplored, the extent of the cephalic neural crest cells insulted genetically or by other causes at a certain time during the development of the embryo might explain the variable phenotypic expression of PHACE syndrome.
