Four-circle diffractometer with three-axis energy analysis
A neutron radiograph film recorded at the ILL in 2005 on NEUTROGRAPH shows the progressive dilution of helium-3 into helium-4 inside a capillary which is at the heart of ultra-low temperature space cryostats. Such an in situ observations is possible only using neutrons where there is a marked isotopic effect for helium (helium-4 is transparent, helium-3 is opaque to neutrons).
Ref.: M. Enderle, S. Pujol, A. Hillenbach (Institut Laue-Langevin), A. Benoit (CRTBT CNRS) (2005) communication privée.