The scanning transmission microscope at the NSLS

The scanning transmission soft X-ray microscope (STXM) that has been under development at the National Synchrotron Light Source [H. Rarback et al., Rev. Sci. Instr. 59 (1988) 52] has been substantially ungraded for operation with the X1 undulator [C. Buckley et al., Rev. Sci. Instr. 60 (1989) 2444]. The principal new features are: optical prefocusing, using a visible light interferometer; a dedicated VAXstation 3200 with a more user friendly and flexible software system for image acquisition and analysis; a flow cell that makes it possible not only to keep the specimen wet during exposure, but to change the fluid around the specimen as well; and a more compact proportional counter that is capable of counting rates of several MHz. In conjunction with new zone plates of better resolution and higher efficiency [E.H. Anderson, SPIE 1160 (1989) 2], the microscope is ready for a period of extended use in biological imaging. © 1990.