<title>Comparison of laser-generated plasma x-ray sources for contact microscopy</title>

Abstract

Soft X-ray contact microscopy (SXCM) is a technique which can image the ultrastructure of living biological specimens at a resolution considerably better than light microscopy (LM). Laser generated plasmas are ideal soft X-ray sources for contact microscopy, since they are capable of providing an intense source of X-rays within the water window region (280-530eV) on a nanosecond timescale. This allows the image to be recorded before the onset of radiation damage and avoids a blurring of the image due to specimen movement. The first experiments used large national laser facilities for X-ray production, although it has become clear that for SXCM to become accessible to the lifescience community, smaller, laboratory scale laser systems are required.Two such laser systems have been developed for the generation of water window X-rays. A small beam line of the large Nd:GLASS laser "Vulcan" at the Rutherford Appleton Laboratory (RAL), UK, has been set up, giving approximately 6-8J on target at a wavelength of 1 .O6zm. In addition, a smaller discharge pumped KrF excimer laser, based at the Clarendon Laboratory, University of Oxford, UK, has been built, giving approximately 2J at a wavelength of 249nm. A comparison of the X-ray emission from plasma generated by the two laser systems using various target materials has been made and evaluated with respect to their application to SXCM.

X‐ray contact microscopy using an excimer laser plasma source with different target materials and laser pulse durations

“…Penumbral blurring arises because of the finite source size (diameter F) and the distance between the specimen and resist (d 1 ). The (Cotton et al, 1993).…”

“…It possesses two flagella (with an approximate diameter of 300 nm) apically inserted, showing positive and negative phototactic movements, and it reproduces by vegetative division and sexual conjugation. These specimens have previously been imaged by SXCM (Cotton et al, 1993).…”

“…1. Absorption in the water window of water and carbon, 1 mm in thickness (Cotton et al, 1993). resolution limit due to penumbral blurring is given by…”

Chemical Microscopy

“…See also: References B1, B4,E10,E15,E17,E26,E31,E34,E38,E39,F3,F20,J1,J3,J7,K36,K75,K96,L10,L33,L34,L39,Q5,T6,V2,AA24,AA26,EE11,EE32,HH4,HH5,HH6,LL2,LL11,LL14.…”

High-resolution X-ray imaging by polycapillary optics and lithium fluoride detectors combination

“…Introduction. -X-ray imaging techniques play a crucial role in understanding the microscopic world: the impressive improvements in all three key elements, X-ray sources, optics and detectors, which form the basis of this technology, make it a powerful tool in life science [1] and biology [2], as well as in materials science, industrial and medical applications.…”