Large water Cherenkov detectors have been successfully used for decades in high- and low-energy particle physics. Nevertheless, detecting neutrons remains a challenge for such detectors since a neutron capture on a hydrogen atom doesn't release a sufficient amount of gamma energy to be observed efficiently. The use of gadolinium in the form of soluble salts has been explored extensively to remedy this issue, as gadolinium exhibits both a very large neutron capture cross section and a subsequent high-energy gamma cascade. However, in order for large gadolinium-loaded detectors to operate stably over long time periods, water optical transparency must be maintained by in situ purification. New methods have been developed involving band-pass molecular filtering. While these methods are very successful, they are expensive and consume considerable power and space as they seek to minimize loss of gadolinium while removing other impurities. For smaller detectors where some gadolinium loss can be tolerated, a less expensive way to do this is very desirable. In this paper, we describe the design, development and testing of a system used to purify the gadolinium-loaded water in the 26-ton ANNIE neutrino detector.

中文翻译：

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钆水用离子交换树脂的研制

几十年来，大型水切伦科夫探测器已成功用于高能和低能粒子物理学。然而，探测中子对于此类探测器来说仍然是一个挑战，因为氢原子上的中子捕获不会释放足够数量的伽马能量以进行有效观察。已经广泛探索使用可溶性盐形式的钆来解决这个问题，因为钆表现出非常大的中子捕获截面和随后的高能伽马级联。然而，为了使载有钆的大型探测器长时间稳定运行，必须通过原位净化来保持水的光学透明度。已经开发了涉及带通分子滤波的新方法。虽然这些方法非常成功，它们价格昂贵且消耗大量能量和空间，因为它们试图在去除其他杂质的同时最大限度地减少钆的损失。对于可以容忍一些钆损失的较小探测器，非常需要一种较便宜的方法来做到这一点。在本文中，我们描述了用于净化 26 吨 ANNIE 中微子探测器中钆水的系统的设计、开发和测试。