Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A robust floating nanoammeter   A circuit capable of measuring nanoampere currents while floating at voltages
up to at least 25kV is described. The circuit relays its output to ground
potential via an optical fiber. We particularly emphasize the design and
construction techniques which allow robust operation in the presence of high
voltage spikes and discharges.

27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int