Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Charged Particle Detection using a CMOS Active Pixel Sensor   Active Pixel Sensor (APS) technology has shown promise for next-generation
vertex detectors. This paper discusses the design and testing of two
generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20
micro-m. Each array is divided into sub-arrays in which different sensor
structures (4 in the first version and 16 in the second) and/or readout
circuits are employed. Measurements of several of these structures under Fe55
exposure are reported. The sensors have also been irradiated by 55 MeV protons
to test for radiation damage. The radiation increased the noise and reduced the
signal. The noise can be explained by shot noise from the increased leakage
current and the reduction in signal is due to charge being trapped in the epi
layer. Nevertheless, the radiation effect is small for the expected exposures
at RHIC and RHIC II. Finally, we describe our concept for mechanically
supporting a thin silicon wafer in an actual detector.

17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th