Trial of very cold neutron radiography in Kyoto University reactor

A practical very cold neutron (VCN) radiography using a neutron imaging plate was carried out in VCN facility, Kyoto University Reactor (KUR: 5 MW). The neutron flux from the VCN bender with the characteristic wavelength of 4.8 nm gives a good image with 5 min irradiation time when CNS was operated. The macroscopic total cross sections of water were measured by imaging plates. It is Σth=0.87 cm−1 measured in KUR E2 thermal neutron radiography facility and that of VCN is ΣVCN=9.4 cm−1. The resolution of water thickness is less than 0.1 mm for VCN radiography and close to the positional resolution of an imaging plate. VCN radiography can show the change of water quantity in gypsophila during a drying procedure.