Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimation of Impact Parameter on event-by-event basis in Nuclear
  Emulsion Detector   Photographic Nuclear Emulsion Detector (PNED) has been in use in nuclear and
particle physics experiments from the begining, often as the major detector
system. However, direct measurement of impact parameter in this detector does
not seem possible due to some limitations. This paper discribe a simple yet
strong method to estimate the impact parameter of events on event-by-event
basis. Though this method is develpoed specifically for the photographic
nuclear emulsion detector, we envision that it should also be applicable to
other multi-target detector systems.

23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th