Lookup NU author(s): Dr Charlie McMonagle,
Dr Mike Probert
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
New methods and advanced materials that significantly reduce the background when collecting single-crystal X-ray diffraction data at ultra-low temperatures using a closed-cycle helium refrigerator are presented here. These include a magnetically controlled internal beamstop and a separate internal collimator that together completely remove the scattering contribution to the background from the beryllium vacuum chamber. Additionally, a new radiation shield made from flexible graphite significantly reduces the background and maintains excellent thermal properties. In combination these improvements have led to a sixfold reduction in the average intensity and a 15-fold reduction in peak intensity of the background observed for diffraction experiments conducted with a closed-cycle helium refrigerator. Moreover, access to ultra-low base temperatures, 2.05 K, has been maintained. The design and implementation of these methods are discussed along with a case study of vitamin C to demonstrate the effectiveness of the improvements.
Author(s): McMonagle CJ, Probert MR
Publication type: Article
Publication status: Published
Journal: Journal of Applied Crystallography
Print publication date: 01/04/2019
Acceptance date: 28/02/2019
ISSN (print): 0021-8898
ISSN (electronic): 1600-5767
Notes: Gold Open Access
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