Odstrcil Michal, Lebugle Maxime, Lachat Thierry, Raabe Jörg, Holler Mirko
Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland.
Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, Villigen 5232, Switzerland.
J Synchrotron Radiat. 2019 Mar 1;26(Pt 2):504-509. doi: 10.1107/S160057751801785X. Epub 2019 Jan 25.
Scanning X-ray microscopy such as X-ray ptychography requires accurate and fast positioning of samples in the X-ray beam. Sample stages often have a high mobile mass as they may carry additional mechanics or mirrors for position measurements. The high mobile mass of a piezo stage can introduce vibrations in the setup that will lead to imaging quality deterioration. Sample stages also require a large travel range which results in a slow positioning step response and thus high positioning overhead. Moving lightweight X-ray optics, such as focusing Fresnel zone plates, instead of the sample can improve the situation but it may lead to undesired variations in the illumination probe which may result in reconstruction artifacts. This paper presents a combined approach in which a slow sample stage mechanism covers the long distance range for a large field of view, and a light-weight optics scanner with a small travel range creates a superimposed motion to achieve a fast step response. The step response in the ptychographic tomography instrument used was thereby improved by an order of magnitude, allowing for efficient measurement without loss of imaging quality.
诸如X射线叠层成像术之类的扫描X射线显微镜需要在X射线束中对样品进行精确且快速的定位。样品台通常具有较高的移动质量，因为它们可能会携带用于位置测量的额外机械装置或镜子。压电样品台的高移动质量会在装置中引入振动，这将导致成像质量下降。样品台还需要较大的行程范围，这会导致定位步进响应缓慢，从而导致较高的定位开销。移动轻质X射线光学元件，例如聚焦菲涅耳波带片，而不是移动样品，可以改善这种情况，但这可能会导致照明探针出现不期望的变化，从而可能导致重建伪像。本文提出了一种组合方法，其中一个慢速样品台机构覆盖大视场的长距离范围，而一个行程范围小的轻质光学扫描器产生叠加运动以实现快速步进响应。由此，所使用的叠层断层成像仪器中的步进响应提高了一个数量级，从而能够在不损失成像质量的情况下进行高效测量。
