Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fiber Bragg Grating (FBG) sensors as flatness and mechanical stretching
  sensors   A novel approach which uses Fibre Bragg Grating (FBG) sensors has been
utilised to assess and monitor the flatness of Gaseous Electron Multipliers
(GEM) foils. The setup layout and preliminary results are presented.

32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga