The dynamical structure factor of solid ~(15)N_2 in the α phase is measured at the IN4 time-of-flight spectrometer at the Institut Laue Langevin, and the potential performance of this substance as a UCN converter is assessed. The cross-section to down-scatter neutrons to ultra-cold-neutron energies is determined as a function of the incident energy, as well as the up-scattering mean free path. The UCN production cross-section is found to be approximately of that of deuterium. However, UCN with energy 181 neV have an up-scattering mean free path of 46 cm at, which is times larger than deuterium. Therefore, a large volume α-~(15)N_2 source may produce an improved UCN density if sufficient isotopic purity can be achieved.
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机译：在Laue Langevin研究所的IN4飞行时间光谱仪上测量了α相中固态〜（15）N_2的动力学结构因子，并评估了该物质作为UCN转换器的潜在性能。根据入射能量以及向上散射的平均自由程确定将中子向下散射为超冷中子能量的横截面。发现UCN的生产横截面约为氘的横截面。但是，能量为181 neV的UCN具有46 cm at的向上散射平均自由程，是氘的几倍。因此，如果可以实现足够的同位素纯度，大体积的α-〜（15）N_2源可能会产生更高的UCN密度。
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