Page 127 - Neutrons for Sciences and Society

Chapter 5: The construction of the reactor and the scientific groups
already come across him in the first chapter since he was the author of the communication in Geneva in 1964 which led to the creation of the ILL. He was soon a key player in the project group, then was recruited by the ILL on 1 January 1970. In these two posts he dealt primarily with the cold source and the neutron guides (which have an in-pile component, and sections outside). These two novel and key features enabled the reactor to outperform
Fig. 5.8: On the left is Paul Ageron(1931-1998), on his right Walter Mampe (1939-1992) and Norman Ramsey (Nobel prize for Physics
1989) who visited regularly after
his retirement and performed many experiments at the ILL with Mampe.
all others. To realise this it was
essential to have a close collaboration between the future users and the project group. With his expertise Paul Ageron was liked and respected by all.
Ageron relied on the low temperature group of the CENG to construct the cold source81. Jean-Marie Astruc, an engineer, was recruited in 1970 to direct the project in the reactor service. Liquid deuterium was chosen because it enabled a large volume (25 litres), sufficient to provide beams for five neutron guides 202
x 33 mm2. In addition the deuterium disrupted the neutron flux much less than liquid hydrogen. The power to be dissipated from the liquid deuterium was about 6 kW, which needed a refrigeration power close to that required for operating the biggest liquid hydrogen bubble-chamber detectors used with large accelerators. Liquifier offers came from the German firm, Linde, and the
81 Described in the publication “La source de neutrons froids pour le réacteur à haut flux franco-allemand de Gre- noble” by Ageron P., Verdier J., Ewald R. and H. D. Harig, Energie Nucléaire (Paris), (1971), 13, p15-21.
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