Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A compact design for velocity-map imaging energetic electrons and ions   We present a compact design for a velocity-map imaging spectrometer for
energetic electrons and ions. The standard geometry by Eppink and Parker [A. T.
J. B. Eppink and D. H. Parker, Rev. Sci. Instrum. 68, 3477 (1997)] is augmented
by just two extended electrodes so as to realize an additional einzel lens. In
this way, for a maximum electrode voltage of 7 kV we experimentally demonstrate
imaging of electrons with energies up to 65 eV. Simulations show that energy
acceptances of <270 and <1,200 eV with an energy resolution of dE / E <5% are
achievable for electrode voltages of <20 kV when using diameters of the
position-sensitive detector of 42 and 78 mm, respectively.

11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin