Low temperature closed cycle refrigerator for neutron and x-ray scattering

该提案旨在资助一种适合于新材料的中子和X射线散射研究的低温闭合循环制冷机。 它将在300 K至1.7 K的温度范围内为单晶和多晶样品提供复杂的样品环境，并能够在较长时间内将温度稳定在0.005 K水平。 该装置的一个定义特征是，它可以安装在麦克马斯特核反应堆的麦克马斯特对准衍射仪的欧拉支架中，也可以安装在麦克马斯特大学的四圆X射线衍射仪中，这样就可以在相同的材料上进行互补的中子和X射线衍射研究。 这将是加拿大唯一一个如此装备的低温样品环境设备，它将使新材料的磁性和化学结构以及相图的复杂研究成为可能。 它的温度控制也将允许进行复杂的临界散射研究。 该仪器还将纳入至少两所大学的研究生和高年级本科生的培训和课程。

This proposal seeks to fund a low temperature closed cycle refrigerator appropriate for neutron and x-ray scattering studies of novel materials. It will provide sophisticated sample environment for single crystal and polycrystal samples over the temperature range from 300 K to 1.7 K and be able to stabilize temperature to the 0.005 K level for extended periods of time. One of this apparatus' defining features is that it will be mountable in both an Eulerian cradle of the McMaster Alignment Diffractometer at the McMaster Nuclear Reactor, and within a four-circle x-ray diffractometer at McMaster University, such that complementary neutron and x-ray diffraction studies can be carried out on the same material. It will be the only such low temperature sample environment apparatus in Canada so equipped, and it will enable sophisticated studies of magnetic and chemical structure and phase diagrams in new materials. Its temperature control will also allow sophisticated critical scattering studies to be carried out. This apparatus will also be incorporated into training and courses for graduate and senior undergraduate students at at least two universities.