Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An ultracold low emittance electron source   Ultracold atom-based electron sources have recently been proposed as an
alternative to the conventional photo-injectors or thermionic electron guns
widely used in modern particle accelerators. The advantages of ultracold
atom-based electron sources lie in the fact that the electrons extracted from
the plasma (created from near threshold photo-ionization of ultracold atoms)
have a very low temperature, i.e. down to tens of Kelvin. Extraction of these
electrons has the potential for producing very low emittance electron bunches.
These features are crucial for the next generation of particle accelerators,
including free electron lasers, plasma-based accelerators and future linear
colliders. The source also has many potential direct applications, including
ultrafast electron diffraction (UED) and electron microscopy, due to its
intrinsically high coherence. In this paper, the basic mechanism of ultracold
electron beam production is discussed and our new research facility for an
ultracold, low emittance electron source is introduced. This source is based on
a novel alternating current Magneto-Optical Trap (the AC-MOT). Detailed
simulations for a proposed extraction system have shown that for a 1 pC bunch
charge, a beam emittance of 0.35 mm mrad is obtainable, with a bunch length of
3 mm and energy spread 1 %.

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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: stat