Backtracking as a way to reconstruct Compton scattered gamma-rays

• A method has been developed to reconstruct the tracks of gamma-rays that have undergone Compton scattering in a high-resolution detector system. The development of this method is focussed on applications in nuclear gamma-ray spectroscopy. In nuclear in-beam gamma-ray spectroscopy a number of (position-sensitive) germanium detectors are placed around a target where the nuclei under investigation are produced. The gamma-rays emitted by the nuclei can have energies up to several MeVs. The nuclear reactions in the target can cause emission of up to 25 coincident gamma-rays and sometimes even more. In order to resolve the individual gamma-rays from such events the detector systems currently under development will have such a high granularity that the energy of scattered gamma-ray will be deposited in several different detector segments. Therefore, in order to determine the initial energies and the first interaction positions, the tracks have to be reconstructed. The reconstruction method presented in this paper is based on the observation that the energy deposition of the final photoelectric interaction after scattering usually falls in a narrow energy band. Starting from points in this energy range attempts are made to reconstruct the tracks using the photoelectric and Compton interaction probabilities and the Compton scattering formula. The method has been tested on simulated events with up to 25 coincident gamma-rays of various energies and with different detector position resolutions. Reconstruction efficiencies of up to 84% have been achieved. (C) 1999 Elsevier Science B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Nyckelord

Tracking

Gamma-ray spectroscopy

Germanium

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