Progress on development of SPIDER diagnostics

SPIDER experiment, the full size prototype of the beam source for the ITER heating neutral beam injector, has to demonstrate extraction and acceleration to 100 kV of a large negative ion hydrogen or deuterium beam with co-extracted electron fraction e¯ /D¯ <1 and beam uniformity within 10%, for up to one hour beam pulse. Main RF source plasma and beam parameters are measured with different complementary techniques to exploit the combination of their specific features. While SPIDER plant systems are being installed, the different diagnostic systems are in the procurement phase. Their final design will be described with a focus on some key solutions and most original and cost effective implementations, following the conceptual design reported in [1,2]. Thermocouples used to measure the power load distribution in the source and over the beam dump front surface will be efficiently fixed with proven technique and acquired through custom electronics. Spectroscopy needs to use well collimated lines of sight and will employ novel design spectrometers with higher efficiency and resolution and filtered detectors with custom built amplifiers. The electrostatic probes will be operated through electronics specifically developed to cope with the challenging environment of the RF source. The instrumented calorimeter STRIKE will use new CFC tiles, still under development. Two linear cameras, one built in house, have been tested as suitable for optical beam tomography. Most of these components are being prototyped or are under test before final production and installation, which will be completed before start of SPIDER operation.