Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optically transparent solid electrodes for precision Penning traps   We have conceived, built, and operated a cryogenic Penning trap with an
electrically conducting yet optically transparent solid electrode. The trap,
dedicated to spectroscopy and imaging of confined particles under large solid
angles is of 'half-open' design with one open endcap and one closed endcap that
mainly consists of a glass window coated with a highly transparent conductive
layer. This arrangement allows for trapping of externally or internally
produced particles, yields flexible access for optical excitation and efficient
light collection from the trapping region. At the same time, it is electrically
closed and ensures long-term ion confinement under well-defined conditions.
With its superior surface quality and its high as well as homogeneous optical
transmission, the window electrode is an excellent replacement for partially
transmissive electrodes that use holes, slits, metallic meshes and the like.

31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph