A method for reversing the velocity spread in neutron beams should boost the accuracy of precision experiments
Neutrons offer a combination of properties that make them exquisitely sensitive and versatile sensors. They are charge neutral, which means they do not interact with electric fields, and they possess a magnetic momentum, making them perceptive to magnetic fields. To achieve the highest sensitivity in neutron-based experiments, researchers aim to produce very dense neutron beams. But they also have to ensure that the density does not decrease as the neutrons are transported from source to target. Addressing this latter issue, an international research team including Yoshichika Seki of the RIKEN Nishina Center for Accelerator-Based Science, Wako, Japan, has demonstrated a method for refocusing a neutron beam that has lost its initial density.