Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simultaneous laser-driven X-ray and two-photon fluorescence imaging of
  atomizing sprays   In this letter we report for the first time the possibility of visualizing an
atomizing spray by simultaneously recording X-ray absorption and 2- photon
laser-induced fluorescence imaging. This unique illumination/detection scheme
was made possible thanks to the use of soft X-rays emitted from a laser-driven
X-ray source. An 800 mJ laser pulse of 38 fs duration is used to generate an
X-ray beam with up to 4.10^8 photons ranging from 1 to 10 keV; allowing
projection radiography of water jets generated by an automotive port fuel
injector. In addition, a fraction of the laser pulse (approximately 10 mJ)is
employed to form a light sheet and to induce 2-photon fluorescence from a dye
added to the water. The resulting high-contrast fluorescence images provide
fine details of the spray structure, with reduced blur from multiple light
scattering, while the integrated liquid mass is extracted from the X-ray
radiography. The combination of these two highly complementary techniques, both
in the visible and in the soft X-ray regime, is very promising for the future
characterization of challenging spray systems as well as for further
understanding the physics of liquid atomization.

12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol