Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Performance of the upgraded ultracold neutron source at Los Alamos
  National Laboratory and its implication for a possible neutron electric
  dipole moment experiment   The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL),
which uses solid deuterium as the UCN converter and is driven by accelerator
spallation neutrons, has been successfully operated for over 10 years,
providing UCN to various experiments, as the first production UCN source based
on the superthermal process. It has recently undergone a major upgrade. This
paper describes the design and performance of the upgraded LANL UCN source.
Measurements of the cold neutron spectrum and UCN density are presented and
compared to Monte Carlo predictions. The source is shown to perform as modeled.
The UCN density measured at the exit of the biological shield was $184(32)$
UCN/cm$^3$, a four-fold increase from the highest previously reported. The
polarized UCN density stored in an external chamber was measured to be $39(7)$
UCN/cm$^3$, which is sufficient to perform an experiment to search for the
nonzero neutron electric dipole moment with a one-standard-deviation
sensitivity of $\sigma(d_n) = 3\times 10^{-27}$ $e\cdot$cm.

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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
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The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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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: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an