JET NEUTRAL BEAM INJECTION SYSTEM. CONSTRUCTION AND COMPONENT TESTS
The two neutral injection systems for JET are each determined by 40 MW beam power extracted from eight sources during 10 s pulses. Under the existing spatial restrictions, this has led to a complex beam line system design. The applied manufacturing techniques and the approach to quality assurance will be discussed. The beam sources have been operated at 80 kV, 60 A, 5 s in hydrogen. Plasma source development has increased the H**+ yield to approximately 84 %. Beamlet steering by aperture offset has experimentally been adjusted to the values required for the restricted Tokamak entrance geometry. A beam source has also been operated at 160 kV, 37 A in deuterium. At the Tokamak the 7 m high injector vacuum box has been installed incorporating a fast shutter and a cryopump. This He cooled pump with 40 m**2 entrance area and 45 % pumping efficiency has successfully been tested as well as the flexible cryoliquid transfer lines. The bakeable valve between injector box and Tokamak vacuum (1.1 m x 0.5 m gate cross-section) has been operated with leak rates < 10**-9 mbar-lambda/s. The sub-system commissioning will be completed by short pulse operation of the beam sources with their final power supplies in situ at the Tokamak and, in parallel to this, testing of the beam line system in the Neutral Injection test bed.
Bibliographic Reference: WRITE TO THE PUBLICATIONS OFFICER, JET JOINT UNDERTAKING, ABINGDON, OXON, OX14 3EA (UK), MENTIONING REPORT JET-P(84)07, 1984
Record Number: 1989123036300 / Last updated on: 1987-01-01
Available languages: en