Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Operation and performance of the ATLAS semiconductor tracker   The semiconductor tracker is a silicon microstrip detector forming part of
the inner tracking system of the ATLAS experiment at the LHC. The operation and
performance of the semiconductor tracker during the first years of LHC running
are described. More than 99% of the detector modules were operational during
this period, with an average intrinsic hit efficiency of (99.74 +/- 0.04)%. The
evolution of the noise occupancy is discussed, and measurements of the Lorentz
angle, delta-ray production and energy loss presented. The alignment of the
detector is found to be stable at the few-micron level over long periods of
time. Radiation damage measurements, which include the evolution of detector
leakage currents, are found to be consistent with predictions and are used in
the verification of radiation background simulations.

32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th