Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Number of photons and brilliance of the radiation from a crystalline
  undulator   The scheme for accurate quantitative treatment of the radiation from a
crystalline undulator in presence of the dechanneling and the photon
attenuation is presented. The number of emitted photons and the brilliance of
electromagnetic radiation generated by ultra-relativistic positrons channeling
in a crystalline undulator are calculated for various crystals, positron
energies and different bending parameters. It is demonstrated that with the use
of high-energy positron beams available at present in modern colliders it is
possible to generate the crystalline undulator radiation with energies from
hundreds of keV up to tens of MeV region. The brilliance of the undulator
radiation within this energy range is comparable to that of conventional light
sources of the third generation but for much lower photon energies.

24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex