Engineering Design Description of Diagnostic Cassettes for Bay J for KSTAR

This report describes the engineering design of diagnostic cassette and its optical configuration for bay J for KSTAR. Bay J dedicates to a visible optical diagnostic including visible survey spectrometer, Hαgonitor, visible Bremsstrahlung array and visible/Hα TV. This cassette design will be a model case as prototype for some other similar port and can be easily modified to a dedicated diagnostics. This report also describes the principal features of the optical lens design and provides some of the calculations for optical transmission made in defining the main components of the optical design. The lens and optical configuration designed by CODE V ray tracing program. Bay J cassette is very large size capable of people entering inside for installation and maintenance. The cassette is made of stainless steel, its weight estimates around 3 tons, windows used for fused silica glass. The shutter operates remotely by pneumatic valve, and protects the window from plasma and neutron radiation during discharge. The clearance between wall and cassette is 20mm. Bay J is wider port with entrance cassette which includes some diagnostics, visible survey spectrometer, Hα monitor, visible Bremsstrahlung array, visible/Hα TV and the filterscope. Hα monitor consists of 20 viewing channels in toroidal direction and having 2 sets of 10 channels for viewing divertor region in poloidal direction. Visible Bremsstrahlung array shares 20 viewing channels with Hα monitor in toroidal direction. The visible survey spectrometer and filterscope has 10 viewing channels in tangential direction, respectively. This work has been carried out through collaboration with the Princeton Plasma Physics Laboratory (PPPL) and Korea Basic Science Institute (KBSI).