Depth Probing Soft X-ray Microprobe (DPSXRM) for High Resolution Probing of Earth’s Microstructural Samples

Abstract:

The Cambrian explosion; occurrence of landslides in very dry weather conditions; rockslides; dead, shriveled-up and crumbled leaves possessing fossil records with the semblance of well preserved, flat leaves; abundance of trilobite tracks in lower and higher rock layers; and sailing stones are enigmas demanding demystifications. These enigmas could be elucidated when data on soil structure, texture and strength are provided by some device with submicrometre accuracy; for these and other reasons, the design of a Depth Probing Soft X-ray Microprobe (DPSXRM), is being proposed; it is expected to deliver soft X-rays, at spatial resolution, ϛ≥600nm and to probe at the depth of 0.5m in 17s.

The microprobe is portable compared to a synchrotron radiation facility (Diamond Light Source has land size of 43,300m²); spatial resolution,ϛ , of the DPSXRM surpasses those of the X-ray Fluorescence microanalysis (10µm), electron microprobe (1-3µm) and ion microprobe (5->30µm); the DPSXRM has allowance for multiple targets.

Vanadium and Manganese membranes are proposed owing to respective 4.952KeV VKα₁ and 5.899KeV MnKα₁ X-rays emitted, which best suits micro-probing of Earth’s microstructural samples.

Compound systems like the Kirk-Patrick and Baez and Wolter optics, aspheric mirrors like elliptical and parabolic optics, small apertures and Abbe sine condition are employed to reduce or remove astigmatism, obliquity, comatic and spherical aberrations—leading to good image quality.

Results show that 5.899KeV MnKα₁ and 4.952KeV VKα₁ soft X-rays will travel a distance of 2.75mm to form circular patches of radii 2.2mm and 2.95mm respectively. Zone plate with nth zone radius of 1.5mm must be positioned 1.5mm and 2mm from the electron gun if circular patches must be formed from 4.952KeV VKα₁ and 5.899KeV MnKα₁ soft X-rays respectively.

The focal lengths of 0.25μm≤ƒ≤1.50μm and 0.04μm≤ƒ≤0.2μm covered by 4.952KeV VKα₁ and 5.899KeV Mn Kα₁ soft X-Rays, will occupy circular patches of area 0.03mm²≤A≤0.2mm² respectively.

The spatial resolution of 244nm≤ϛ≤1460nm is attainable for focal lengths of 38.1nm≤ƒ≤229nm and 32.0.nm≤ƒ≤1460192nm covered by 5.899KeV Mn Kα₁ and 4.952KeV VKα₁ soft X-rays, respectively.