X-Ray microscopy in the water window allows imaging with resolutions in the nanometer regime as well as a high natural contrast between carbon and oxygen. Hence, it is possible to examine aqueous biological samples with up to 10 µm thickness in their natural state. Apart from cryo fixation of the specimen, which is usually required in order to avoid radiation damage, extensive sample preparation is not necessary. The use of highly brilliant laboratory X-ray sources has allowed the transfer of this technology, previously limited to synchrotron facilities, into the laboratory. This transfer inures to the benefit of a broader scientific community for applications in various fields such as medicine, biology and environmental sciences.
We introduce the plasma driven laboratory full-field transmission X-ray microscope (LTXM) located at the Berlin Laboratory for innovative X-ray technologies [1]. The half-pitch resolution of ∆x = (31 ± 3) nm is comparable to resolutions achieved at synchrotron facilities. The used wavelength at 2.478 nm is close to the absorption edge of oxygen and thus offers the best contrast within the water window. The large penetration depth and the short exposure times of less than one minute reached by the microscope, make soft X-ray cryo tomography feasible. An overview of first applications, like measurements on cryo-frozen yeast cells and human skin slices, will be given.
References
[1] H. Legall, G. Blobel, H. Stiel, C.Seim et al., “Compact x-ray microscope for the water window based on a high brightness laser plasma source,” Opt.Express, 20(16), 18369-18369 (2012).
This project was funded by the BMBF (#13N8913) and the BMVBS (WTW #03WWBE106).