A combined small- and wide-angle x-ray scattering detector for measurements on reactive systems

Abstract

A detector with high dynamic range designed for combined small- and wide-angle x-ray scattering experiments has been developed. It allows measurements on single events and reactive systems, such as particle formation in flames and evaporation of levitating drops. The detector consists of 26 channels covering a region from 0.5° to 60° and it provides continuous monitoring of the sampled signal without readout dead time. The time resolution for fast single events is about 40 μs and for substances undergoing slower dynamics, the time resolution is set to 0.1 or 1 s with hours of continuous sampling. The detector has been used to measure soot particle formation in a flame, burning magnesium and evaporation of a toluene drop in a levitator. The results show that the detector can be used for many different applications with good outcomes and large potential.

Distinguishing Gas-Phase and Nanoparticle Contributions to Small-Angle X-ray Scattering in Reacting Aerosol Flows

“…Although there is a significant body of work describing the use of SAXS to measure particle sizes in flames, ,,− most of these studies have focused on measuring size distributions of mature particles that have formed aggregates tens of nanometers in size. Previous studies have attempted to isolate the particle signal by making SAXS measurements outside the flame or with the flame turned off − or at locations in the flame where contributions from particles are assumed to be minimal − and subtracting this signal from that of the regions of the flame where particle concentrations are significant.…”

In-situ neutron imaging of hydrogenous fuels in combustion generated porous carbons under dynamic and steady state pressure conditions

“…It can also have positive aspects in that it may play an important role for clean energy conversion in combustion due to its material properties such as low density and fractal structure. In connection to our investigations on ethylene atmospheric pressure flames and soot condensation on metal plates utilizing in-situ X-ray scattering diagnostics [6][7][8][9], we obtained fractal-like (carbon) low-density soot materials (below 100 mg cm -3 ) [6,7]. This material showed considerable "thermal elasticity" with a density that changed by 30% between 300 and 600 K, approximately.…”

Soot-particle core-shell and fractal structures from small-angle X-ray scattering measurements in a flame

“…There have been many studies in which SAXS was used to measure particle sizes in flames [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] and in explosion-detonation fronts [45][46][47]. In such studies, a collimated beam of monochromatic hard X-ray photons is passed through the flame or detonation front, and forwardscattered photons are collected as a function of scattering angle on a position-sensitive detector downstream of the flame.…”