Development of Phase Contrast X-ray Microscopy

我们建议开发两种新的X射线操作模式 显微镜将利用相位对比成像 厚的水合生物样品，60 nm或更好 分辨率 与当前X射线显微镜相比 相衬显微镜使用吸收对比， 在某些波长下更高的固有对比度的前景 从而减少辐射剂量， 穿透力和景深的厚标本。 一 全息相衬X射线显微镜即将研制成功 其将使用光致抗蚀剂检测器以高空间分辨率记录 分辨率参考波和 通过时发生振幅和相位变化的波 通过样品，将恢复复杂的样品波 通过数字全息图重建。 微分相位 将开发对比X射线显微镜， 菲涅耳波带片形成聚焦X射线点， 扫描样品，并将使用光学杠杆检测器 为了测量折射率梯度以及X射线吸收 在样品中。 将验证这些显微镜的操作 通过成像测试对象，然后他们的操作将是 使用各种水合和未切片的 生物标本

We propose to develop two new operational modes of x-ray microscopes which will make use of phase contrast for imaging thick, hydrated biological specimens with 60 nm or better resolution. Compared to current to current x-ray microscopes which use absorption contrast, phase contrast microscopes offer the promise of higher intrinsic contrast at certain wavelengths and thus reduced radiation dose, plus the possibility of improved penetration and depth of field for thick specimens. A Holographic Phase Contrast X-ray Microscope will be developed which will use a photoresist detector to record with high spatial resolution the interference pattern between a reference wave and a wave which has undergone amplitude and phase changes by passage through the specimen; the complex specimen wave will be recovered by numerical hologram reconstruction. A Differential Phase Contrast X-ray Microscope will be developed which will use a Fresnel zone plate to form a focusses x-ray spot through which a sample is scanned, and which will use an optical lever detector to measure refractive index gradients as well as x-ray absorption in the sample. Operation of these microscopes will be verified by imaging test objects, and then their operation will be demonstrated using a variety of hydrated and unsectioned biological specimens.