Page 187 - Neutrons for Sciences and Society

Chapter 7 - Maturity
was launched by Jules Horowitz who knew how to convince the other partners to finance it. The arrival of the British had greatly increased demand on various instruments. It was hence necessary to build new instruments and further optimise the existing
ones. The choices were made in consultation with the Scientific Council, which finalised its recommendation in the meeting of 18 March 1978. The new infrastructure included a new Central Computer (DEC1091, after a protracted 18 month multi-national tender operation), and total replacement of the CARINE system by individual mini-computers for each instrument.
More important was the replacement of the cold source with a new design106 which has led to an increase in flux by a factor of about 1.6 (Fig. 7.4). It was also possible to add a vertical beam tube exiting at the control-room level of the reactor, creating a new experimental zone. This vertical beam tube served to increase greatly the source of ultra-cold neutrons. Then, in December 1981, the Steering Committee approved the construction of a second cold source. This was installed in a horizontal beam tube, and was foreseen to have three neutron guide tubes which would terminate in a second hall adjacent to the reactor building. The new source was operational in 1987 with a new beam tube constructed using zircaloy to have a longer life under irradiation.
106 Paul Ageron conceived the new design which consisted of introducing a cavity filled with deuterium gas into the sphere containing the liquid deuterium. This conserved the dimensions of the source feeding the guides. Calculations predicted an increase in the flux of cold neutrons which was confirmed in practice.
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