Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light-sheet imaging for the recording of transverse absolute density
  distributions of gas-phase particle-beams from nanoparticle injectors   Imaging biological molecules in the gas-phase requires novel sample delivery
methods, which generally have to be characterized and optimized to produce
high-density particle beams. A non-destructive characterization method of the
transverse particle beam profile is presented. It enables the characterization
of the particle beam in parallel to the collection of, for instance,
x-ray-diffraction patterns. As a rather simple experimental method, it requires
the generation of a small laser-light sheet using a cylindrical telescope and a
microscope. The working principle of this technique was demonstrated for the
characterization of the fluid-dynamic-focusing behavior of 220 nm polystyrene
beads as prototypical nanoparticles. The particle flux was determined and the
velocity distribution was calibrated using Mie-scattering calculations.

13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom