Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Progress Towards A Permanent Octupole Magnetic Ultra-Cold Neutron Trap
  for Lifetime Measurements   The current knowledge of the neutron $\beta$-decay lifetime has come under
scrutiny as of late due to large disagreements between recent precise
measurements. Measurements using magnetically trapped Ultra-Cold Neutrons
(UCNs) offer the possibility of storage without spurious losses which can
provide a reliable value for the neutron lifetime. The progress towards
realizing a neutron lifetime measurement using a Ioffe-type trap made with a
Halbach-type permanent octupole magnet is presented here. The experimental
procedure extracts a gas of UCNs into vacuum, which reduces many known channels
of neutron losses, and detects the neutron decays via in-situ detection of the
produced protons.

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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: math-ph
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg