The objective of this work was to determine experimentally the efficiency of a solid state 6LiD converter to transform thermal neutrons to ~14-MeV fusion neutrons, using the ex-perimental channel (60-mm diameter) of the IWW-2M reactor at SF NIKIET, Zarechny, Russia.

Measurements were taken using zirconium activation indicators (90Zr (n, 2n) 89Zr) having a threshold energy of Ethr @ 12 MeV and a copper thermal neutron monitor (63Cu(n,g)64Cu).

The 6LiD converter experimental device included diagnostic and background cells. The diagnostic cell was fabricated as a sealed stainless steel triple-layer sample consisting of two flat 6LiD converting layers and an intermediate zirconium layer. The background cell sub-stituted 6LiH layers for the 6LiD layers of the diagnostic cell. It was possible to separately measure neutrons arising from the D(T,n)4He and the 6Li(T,n)8Be reactions.

The experimental device was placed in the IWW-2M reactor experimental channel and irradiated for 20 minutes at the full reactor power of 15 MW. The thermal neutron flux at the center of this experimental channel, when empty, is @3.2 x10¹⁴n/cm²s. The variation in the flux resulting from the introduction of the converter into the channel was calculated by the Monte Carlo method and was accounted for when the conversion factor, K, was calculated.

The measured value of the 14-MeV fusion neutron flux generated by the D(T,n)4He reaction at the point where the zirconium indicator was placed was j=3.6 x 10¹⁰ n/cm²×s. The 6LiD layer conversion factor was determined to be KDT»5.1 x10^-4, and the conversion factor of the experimental device as a whole was K0DT»1.2 x10^-4. Thus, a fluence of fusion neutrons of @5 x10¹⁶ n/cm² for a 500-hour cycle at the reactor capacity of 15 MW could be obtained in the IWW-2M reactor.

ąWork supported by the International Science and Technology Center (Project #019-94).