Infrared imaging diagnostics for INTF ion beam

Abstract

In India, testing facility named INTF [1] (Indian test facility) is being built in Institute for Plasma Research to characterize ITER-Diagnostic Neutral Beam (DNB). INTF is expected to deliver 60A negative hydrogen ion beam current of energy 100keV. The beam will be operated with 5Hzmodulation having 3s ON/20s OFF duty cycle. To characterize the beam parameters several diagnostics are at different stages of design and development. One of them will be a beam dump,made of carbon fiber composite (CFC) plates placed perpendicular to the beam direction at a distance lm approximately. The beam dump needs to handle ∼ 6MW of beam power with peak power density ∼ 38.5MW/m 2 . The diagnostic is based on thermal (infra-red-IR) imaging of the footprint of the 1280 beamlets falling on the beam dump using four IR cameras from the rear side of the dump. The beam dump will be able tomeasure beam uniformity, beamlet divergence. Itmay give information on relative variation of negative ion stripping losses for different beam pulses. The design of this CFC based beam dump needs to address several physics and engineering issues, including some specific inputs frommanufacturers. Themanuscript will describe an overview of the diagnostic system and its designmethodology highlighting those issues and the present status of its development.