Ultrabright multikilovolt coherent tunable x-ray source at lambda similar to 2.71-2.93 angstrom

摘要

Detailed molecular structural information of the living state is of enormous significance to the medical and biological communities. Since hydrated biologically active structures are small delicate complex three-dimensional (3D) entities, it is essential to. have molecular scale spatial resolution, high contrast, distortionless, direct 3D modalities of visualization. of naturally functioning specimens in order to faithfully reveal their full molecular architectures. An x-ray holographic microscope equipped with an x-ray laser as the illuminator would be uniquely. capable of providing these images. A quantitative interlocking concordance of physical evidence, that includes (a) the observation of strong enhancement of selected spectral components of several Xeq+ hollow-atom transition arrays (q = 31, 32, 34, 35, 36, 37) radiated axially from confined plasma channels, (b) the measurement of line narrowing that, is spectrally correlated with the amplified transitions, (c) evidence for spectral hole-burning in the spontaneous emission, a manifestation of saturated amplification, that corresponds spectrally with the amplified lines, and (d) the detection of an intense narrow (deltatheta(x) similar to 0.2 mrad) directed beam of radiation, (1) experimentally demonstrates in the lambda congruent to 2.71-2.93 Angstrom range ((h) over bar omega(x) congruent to 4230-4570 eV) the operation of a new concept capable of producing the ideal conditions for amplification of multikilovolt x-rays and (2) proves the feasibility of a compact x-ray illuminator that can cost-effectively achieve the mission of biological x-ray microholography. The measurements also (a) establish the property of tunability in the quantum energy over a substantial fraction of the spectral region exhibiting amplification (Delta(h) over bar omega(x) similar to 345 eV) and (beta) demonstrate the coherence of the x-ray output through the observation of a canonical spatial mode pattern. An analysis of the physical scaling revealed by these results indicates that the capability of the x-ray source potentially includes. single-molecule microimaging, the key for the. in situ structural analysis of membrane proteins, a cardinal class of drug targets. An estimate of the peak brightness achieved in these initial experiments gives a value of similar to10(31)-10(32) photons s(-1) mm(-2) mrad(-2)/(0.1% bandwidth), a magnitude that is similar to10(7)-10(8)-fold higher than presently available synchrotron technology. [References: 39]