DEVELOPMENT OF THE NEUTRON FILTERS FOR JET GAMMA-RAY CAMERAS

S. SOARE¹, M. CURUIA¹, V. KIPTILY², A. MURARI³, P. PRIOR², V. ZOITA⁴, M. ANGHEL¹, G. BONHEURE⁵, M. CONSTANTIN¹, E. DAVID¹, T. EDLINGTON², S. GRIPH², F. LE GUERN⁶, Y. KRIVCHENKOV², S. POPOVICHEV², V. RICCARDO², B. SYME², V. THOMPSON², AND JET EFDA CONTRIBUTORS*

¹Association EURATOM-MEdC, National Institute for Cryogenics and Isotopic Technologies, Rm. Valcea, Romania,e-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
²Association EURATOM-UKAEA/JOC, Culham Science Centre, Abingdon, UK
³Association EURATOM-ENEA, RFX, Padova, Italy
⁴Association EURATOM-MEdC, National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania
⁵Association EURATOM-Belgian State, LPP-ERM/KMS, B 1000 Brussels, Belgium
⁶JET-CSU, Culham Science Centre, Abingdon, UK

ABSTRACT:

The JET gamma-ray camera diagnostics have already provided valuable information on the gamma-ray imaging of fast ion in JET plasmas /1, 2/. The JET Gamma-Ray Cameras (GRC) upgrade project deals with the design of appropriate neutron/gamma-ray filters (“neutron attenuators”). The main design parameter was the neutron attenuation factor. The two design solutions, that have been finally chosen and developed at the level of scheme design, consist of: a) one quasi-crescent shaped neutron attenuator (for the horizontal camera) and b) two quasi-trapezoid shaped neutron attenuators (for the vertical one). Various neutron-attenuating materials have been considered (lithium hydride with natural isotopic composition and 6Li enriched, light and heavy water, polyethylene). Pure light water was finally chosen as the attenuating material for the JET gamma-ray cameras. FEA methods used to evaluate the behaviour of the filter casings under the loadings (internal hydrostatic pressure, torques) have proven the stability of the structure.
KEYWORDS: tokamak, diagnostics, gamma-rays