The neutron grid has a plurality of spacers that transmit at least part of the first neutrons that pass through the object, and a plurality of absorbers that absorb at least part of the second neutrons scattered by the object. And a grid portion in which spacers and absorbers are alternately arranged along the first direction and extend along a second direction intersecting the first direction, and the first direction and the second direction. And a pair of cover members that sandwich the grid portion along the intersecting third direction and transmit at least part of the first neutron and at least part of the second neutron. The difference in thermal expansion coefficient between the spacer and the absorber is within ± 9 × 10 −6 / ° C., or the Young's modulus of the spacer is 100 GPa or more.
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