An achromatic neutron lens

Neutrons provide exceptional insight into materials, owing to their sensitivity to light elements, isotopic composition, magnetic moments, and high-penetration. However, neutron sources are polychromatic and of low brightness. Neutron optics provides a route to address these limitations by focusing, and to date, various types of neutron optics have been developed based on reflection, refraction, diffraction, and magnetism. Notably, compound refractive lenses and Fresnel zone plates have been demonstrated for imaging, yet their severe chromatic aberration under polychromatic beams has prevented their widespread use and limits progress towards true high-resolution neutron microscopy. Here, we demonstrate an achromatic neutron lens for full-field neutron microscopy. This development overcomes the intrinsic sample-detector distance constraint in pinhole-based radiography. The lens magnification enables the use of efficient detection systems without loss of spatial resolution and establishes a pathway towards high-resolution neutron microscopy. We anticipate the neutron achromat will advance a broad range of neutron methods.