Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Horizontal Emittance Reduction on a Synchrotron Radiation Light Source
  with a Robinson Wiggler   The performance of synchrotron light facilities are strongly influenced by
the photon beam bright- ness, that can be further increased by reducing the
beam emittance. A Robinson Wiggler can be installed in a non-zero dispersion
straight section to reduce the horizontal beam emittance. It is composed of an
array of magnets of alternated polarities, whose both magnetic field and
gradient are of opposite signs. It provides a compact solution to reduce by 50%
the horizontal emittance. How- ever, it increases the energy spread by 40%. The
concept of the Robinson Wiggler (RW) is described here, the first experimental
observation of the Robinson effect in a synchrotron light source on the
transverse and longitudinal beam properties by the means of four existing
undulators is presented and the impact on the photon flux density is studied.

16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
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The categories of this paper are: q-fin