A proton activation diagnostic to measure D–3He reaction yields : Proceedings of the 9th topical conference on high temperature plasma diagnostics

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We are developing activation diagnostics for monitoring energetic charged-particle fluxes in space and laboratory plasmas. More immediately, we plan to use activation to measure the time-integrated proton flux from D–3He fusion reactions in Alcator C-MOD, providing a measure of the time-averaged D–3He fusion rate. We demonstrated the technique's feasibility by inducing significant gamma activity in a titanium sample exposed to D–3He protons created in our Cockcroft–Walton generator. The titanium target received a fluence of 5.5×109 protons at 14.7 MeV (of order what a 3-cm2 target should receive from one shot in Alcator C-MOD) and became activated by the48Ti(p,n)48V reaction. The activity's spectrum from a high-purity germanium (HPGe) detector showed the characteristic 0.984- and 1.312-MeV lines of 48V. The measured activity agreed reasonably well with theory. An absence of activity at those energies before D–3He activation eliminated background or D–D product-induced activity as the gamma source. We intend to repeat the experiment with a chromium target to evaluate that material's diagnostic potential.

Electronic Resource