Producing parallel x rays with a bent‐crystal monochromator and an x‐ray tube

Abstract

A bent Laue monochromator and a conventional x-ray tube were used to produce a fan beam that was parallel in the plane perpendicular to the plane of the fan. The x-ray fan beam was tunable in energy and had about 12% energy bandwidth at a slice height of 5 mm when tuned to 50 keV. The beam's energy was slightly coupled to the vertical position on the beam's height. The slice height could be varied from 1 to 10 mm. The flux at 50 keV was approximately 2x10(6) photons/mm2/s with a rotating anode tungsten x-ray tube operating at 120 kVp and 100 mA. The narrow energy bandwidth of the beam produced is advantageous over a conventional divergent polychromatic beam for all radiography applications, while the parallelism of the beam enhances its intensity by about threefold and offers some advantages for computed tomography.

Phase-space matching between bent Laue and flat Bragg crystals

“…The vertical line corresponding to = 2 c means that in this case the output beam is a parallel beam with a divergence of 0. When the bending is twice what is required for inverse Cauchois geometry, a bent Laue crystal outputs a parallel beam, as derived theoretically and proven experimentally by Zhong et al (2001). This special case again validates the Dumond diagram.…”

“…is positive when the source point is on the concave side of the crystal (as in Fig. 2) and negative with the source on the convex side (Zhong et al, 2001). The upper sign corresponds to when the source and the center of bending are on the same side of the crystal's lattice plane (as shown in Fig.…”

Investigation of externally activated x-ray fluorescence tomography for use in medical diagnostics

“…However, when a larger relative energy width of the spectrum is acceptable, the intensity of some tube concepts is less than two orders of magnitude smaller than that of a conventional bremsstrahlung CT tube. 6 Generally, the impact of multi-modality imaging scanners like PET-CT or SPECT-CT is continually growing. A combined transmission and fluorescence CT scanner with its inherently registered images could represent a candidate in this arena.…”

Microbeam radiation therapy: a review

“…MRT employs parallel arrays of microscopically thin planar beams of synchrotron-generated X-rays. MRT research is being pursued both at the Brookhaven National Laboratory (BNL), New York, USA, where the method was initiated in the early 1990s (Slatkin et al, 1992(Slatkin et al, , 1995Dilmanian et al, 2001;Zhong et al, 2001) and at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France where the method has been studied since the mid1990s (Laissue et al, , 1998Thomlinson et al, 2000). Normal tissues are more tolerant of such microscopic inhomogeneity of dose than neoplasms, a serendipitous generality that enhances the efficacy of the therapy (Brauer-Krisch et al, 2005;Gueulette et al, 2005).…”