Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum efficiency of technical metal photocathodes under laser
  irradiation of various wavelength   Quantum efficiency studies for various wavelength and various technical metal
surfaces were carried out in a dedicated unbaked vacuum chamber. Copper,
magnesium, aluminium and aluminium-lithium photocathodes were irradiated by two
different high power, high repetition rate, laser systems. We have observed an
emission of electrons for photon energy below the work function of the
material. This is explained by multiple photon absorption at the photocathode.
We have not observed any degradation of the QE for those materials, but an
improvement when irradiating them over a long period of time. This is contrary
to observations made in RF photoguns.

24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph