Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Design of a High-bunch-charge 112-MHz Superconducting RF Photoemission
  Electron Source   High-bunch-charge photoemission electron-sources operating in a continuous
wave (CW) mode are required for many advanced applications of particle
accelerators, such as electron coolers for hadron beams, electron-ion
colliders, and free-electron lasers (FELs). Superconducting RF (SRF) has
several advantages over other electron-gun technologies in CW mode as it offers
higher acceleration rate and potentially can generate higher bunch charges and
average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed
at Brookhaven National Laboratory (BNL) to produce high-brightness and
high-bunch-charge bunches for the Coherent electron Cooling Proof-of-Principle
(CeC PoP) experiment. The gun utilizes a quarter-wave resonator (QWR) geometry
for assuring beam dynamics, and uses high quantum efficiency (QE) multi-alkali
photocathodes for generating electrons.

18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
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The categories of this paper are: eess
5
The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg