Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: LCLS-II-HE verification cryomodule high gradient performance and quench
  behavior   An 8-cavity, 1.3 GHz, LCLS-II-HE cryomodule was assembled and tested at
Fermilab to verify performance before the start of production. Its cavities
were processed with a novel nitrogen doping treatment to improve gradient
performance. The cryomodule was tested with a modified protocol to process
sporadic quenches, which were observed in LCLS-II production cryomodules and
are attributed to multipacting. Dedicated vertical test experiments support the
attribution to multipacting. The verification cryomodule achieved an
acceleration voltage of 200 MV in continuous wave mode, corresponding to an
average accelerating gradient of 24.1 MV/m, significantly exceeding the
specification of 173 MV. The average Q0 (3.0x10^10) also exceeded its
specification (2.7x10^10). After processing, no field emission was observed up
to the maximum gradient of each cavity. This paper reviews the cryomodule
performance and discusses operational issues and mitigations implemented during
the several month program.

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The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
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The categories of this paper are: econ
25
The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys