Design and Construction of a Fast Ion Loss Faraday Cup Array Diagnostic for JET
Authors: D.S. Darrow, S. Bäumel, F.E. Cecil, V. Kiptily, R. Ellis, L. Pedrick, and A. Werner
Date of PPPL Report: April 2004
Presented at: the 15th APS High Temperature Plasma Diagnostics Conference,19 - 22 April 2004, San Diego, CA. Proceedings to be published in the Review of Scientific Instruments.
A thin foil Faraday cup array is being built to measure the loss of 3.5 MeV alpha particles and MeV ion cyclotron heating (ICH) tail ions on JET. It will consist of nine detectors spread over five different poloidal locations and three radial positions. They will measure the poloidal distribution and radial scrape off of the losses. The detectors will be comprised of four layers of thin (2.5 micron) Ni foil, giving some resolution of the lost particle energy distribution as different ranges of energies will stop in different layers of the detector. One detector will utilize eight thinner (1.0 micron) foils to obtain a better resolved energy distribution. These detectors will accept particles incident up to 45° from the normal to the foils.