Positronium Formation and Decay in Organic Scintillators for Neutrino Detection


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The detection of electron anti-neutrinos is generally carried out by searching for the coincidence of the reaction products, neutron and positron, in liquid scintillators. However, in these last a positron may form positronium (Ps) with an electron of the medium; efficiency of the process may be high. Furthermore, the triplet ground state sublevel (o-Ps) has lifetimes of a few ns. These features introduce distortions in the time distribution of the emitted photons, which is essential for position reconstruction and pulse shape discrimination algorithms in anti-neutrino experiments. This drawback can be favorably exploited by using o-Ps as a probe to detect anti-neutrinos in the scintillator. We report results of positron annihilation lifetime measurements in some organic liquid scintillators used for neutrino experiments. The o-Ps induced distortion of the scintillation photon emission time distribution may enhance the anti-neutrino detection.



Edited by:

Jozef Krištiak, Jan Kuriplach and Pradeep K. Pujari




G. Consolati et al., "Positronium Formation and Decay in Organic Scintillators for Neutrino Detection", Materials Science Forum, Vol. 733, pp. 306-309, 2013

Online since:

November 2012




[1] F. Ardellier et al., arXiv: hep-ex/0606025.

[2] Xin-Heng Guo et al., arXiv: hep-ex/0701029.

[3] K. K. Joo et al., Nucl. Phys. Proc. Suppl. 168 (2007), 125.

[4] G. Alimonti et al., Nucl. Instrum. Methods Phys. Res. Sect. A 600 (2009), 568.

[5] S. Abe et al., Phys. Rev. Lett. 100 (2008), 221803.

[6] P.G. Coleman, in: Principles and Applications of Positron and Positronium Chemistry , edited Y.C. Jean, P.E. Mallon and D.M. Schrader, Worls Scientific, New Jersey (2003), pp.37-72.

[7] I. K. MacKenzie, in: Positron Solid-State Physics, edited by W. Brandt and A. Dupasquier, North-Holland, Amsterdam (1983), p.214.

[8] J. Kansy, Nucl. Instrum. Methods Phys. Res. Sect. A 374 (1996), 235.

[9] O. Ju. Smirnov, Instrum. Exp. Tech. 46 (2003), 327.

[10] F. Elisei et al., Nucl. Instrum. Methods Phys Res. Sect. A 400 (1997), 53.