The use and characterization of a backilluminated charge-coupled device in investigations of pulsed x-ray and radiation sources

Abstract

Examinations of bremsstrahlung and energetic electron beams from a novel laser plasma source motivate and assist characterization of a backthinned, backilluminated direct detection x-ray charge-coupled device (CCD), a topology that is uncommon in hard x-ray work. Behavior toward pseudomonochromatic ((55)Fe) and multichromatic ((241)Am) sources is briefly reviewed under optimized noise conditions. Results collectively establish the previously unknown functional depth structure. Several modes of usage are illustrated in approximately 4-20 keV x-ray laser plasma source investigations, where the significance of the characterization is briefly discussed. The spectral redistribution associated with this CCD topology is unfavorable, yet appropriate analysis ensures that sufficient spectral information remains for quantitative determination of broadband x-ray flux and spectra in essentially single laser shot measurements. The energy dependence of nascent electron cloud radii in silicon is determined using broadband x-rays from the laser plasma source, turning the narrow depletion depth to advantage. Finally, the characterization is used to quantify recent x-ray spectral explorations of the water jet laser plasma source operating under aspirator vacuum. These results will have key value for establishment of laboratory based ultrafast extended x-ray absorption fine structure experiments using microbolometric detectors.

Revisiting Bragg's X-ray microscope: Scatter based optical transient grating detection of pulsed ionising radiation

“…One contributing aspect is that for non-holographic scatter techniques, only the squared modulus (the intensity) of the complex wavefield is registered by the detector, corresponding to measuring only the moduli of the sample's spatial Fourier components; phase information is lost. Next, ultrafast measurements from short-pulsed X-ray sources [42,43] cannot use time-of-flight techniques for energy-resolution, such as are used in neutron and electron scattering momentum transfer experiments [74][75][76][77][78]. Instead, scattered X-ray photons arrive essentially simultaneously at a detector, for which counterbased approaches are impossible.…”

“…Fast and ultrafast synchronously pulsed X-ray/laser capabilities enable the study of transient molecular structures [38,39], a capability that is rapidly evolving on sub-picosecond timescales, in non-crystalline samples and on a laboratory scale [32,[40][41][42][43]. Atomic spatial resolution is natural using correspondingly short X-rays or matter waves such as electrons or neutrons.…”

Table-Top Ultrafast X-Ray Microcalorimeter Spectrometry for Molecular Structure

“…The novel combination of a pulsed-laser-generated, broadband, hard x-ray source with a photon-measuring cryogenic microcalorimeter array has been motivated previously [10][11][12][13]. It promises spectroscopic ultrafast structural measurements with photon-counting rates that, in the prototype version discussed in this Letter, are comparable to established techniques such as electron-beam slicing at synchrotrons and focusing-crystal geometries [1,14].…”

“…The setup allows simultaneous observation of multiple absorption edges and considerable flexibility for binning during and after the experiment. This demonstration is a critical development in the advancement of inhouse molecular structure analysis, particularly for subpicosecond pump-probe studies in condensed phases [3,[10][11][12]15]. This publication aims to demonstrate the new opportunities and presents, for the first time, a hard x-ray absorption fine-structure spectrum recorded with a highly efficient energy-dispersive detector.…”

“…The jet is operated at water aspirator vacuum pressure ($ 25 torr at 21 C) and enclosed by a target chamber constructed from 8 mm thick aluminum. The flux, spectral, and temporal properties of the x rays emitted at this laser pulse energy were described previously [10,11]. Efforts were made to ensure sufficient temporal contrast when operating the laser, to avoid generation of high-energy electron beams and concomitant reduction of target-generated x-ray flux [16].…”