Thu·Feb 18, 2016Thursday·February 18, 2016

1. 01*

   Design of the SABAT system for underwater detection of dangerous substances

   M. Silarski🇵🇱 · D. Hunik · M. Smolis · S. Tadeja · P. Moskal🇵🇱

   We present status of simulations used to design a novel device for the detection of hazardous substances in the aquatic environment using neutron activation. Unlike the other considered methods based on this technique we propose to use guides for neutron and gamma quanta which speeds up and simplifies identification. First preliminary results show that both the neutron guide and the $\gamma$ ray guide increase the performance of underwater threats detection.

   nucl-exphysics.ins-detActa Phys.Polon.B(2016)·3 citations
2. 02*

   Potential of the J-PET detector for studies of discrete symmetries in decays of positronium atom - a purely leptonic system

   P. Moskal🇵🇱 · D. Alfs🇵🇱 · T. Bednarski🇵🇱 · P. Białas🇵🇱 · E. Czerwiński🇵🇱 · C. Curceanu🇮🇹 · A. Gajos🇵🇱 · B. Głowacz🇵🇱 · M. Gorgol🇵🇱 · B. C. Hiesmayr🇦🇹 · B. Jasińska🇵🇱 · D. Kamińska🇵🇱 and 15 other authors

   The Jagiellonian Positron Emission Tomograph (J-PET) was constructed as a prototype of the cost-effective scanner for the simultaneous metabolic imaging of the whole human body. Being optimized for the detection of photons from the electron-positron annihilation with high time- and high angular-resolution, it constitutes a multi-purpose detector providing new opportunities for studying the decays of positronium atoms. Positronium is the lightest purely leptonic object decaying into photons. As an atom bound by a central potential it is a parity eigenstate, and as an atom built out of an electron and an anti-electron it is an eigenstate of the charge conjugation operator. Therefore, the positronium is a unique laboratory to study discrete symmetries whose precision is limited in principle by the effects due to the weak interactions expected at the level of (~10${}^{-14}$) and photon-photon interactions expected at the level of (~10${}^{-9}$). The J-PET detector enables to perform tests of discrete symmetries in the leptonic sector via the determination of the expectation values of the discrete-symmetries-odd operators, which may be constructed from the spin of ortho-positronium atom and the momenta and polarization vectors of photons originating from its annihilation. In this article we present the potential of the J-PET detector to test the C, CP, T and CPT symmetries in the decays of positronium atoms.

   nucl-exphysics.ins-detActa Phys.Polon.B(2016)·92 citations
3. 03*

   Determination of the 3\gamma fraction from positron annihilation in mesoporous materials for symmetry violation experiment with J-PET scanner

   B. Jasińska🇵🇱 · M. Gorgol🇵🇱 · M. Wiertel · R. Zaleski · D. Alfs🇵🇱 · T. Bednarski🇵🇱 · P. Białas🇵🇱 · E. Czerwiński🇵🇱 · K. Dulski · A. Gajos🇵🇱 · B. Głowacz🇵🇱 · D. Kamińska🇵🇱 and 21 other authors

   Various mesoporous materials were investigated to choose the best material for experiments requiring high yield of long-lived positronium. We found that the fraction of 3\gamma annihilation determined using \gamma-ray energy spectra and positron annihilation lifetime spectra (PAL) changed from 20% to 25%. The 3gamma fraction and o-Ps formation probability in the polymer XAD-4 is found to be the largest. Elemental analysis performed using scanning electron microscop (SEM) equipped with energy-dispersive X-ray spectroscop EDS show high purity of the investigated materials.

   nucl-exphysics.ins-detActa Phys.Polon.B(2016)·50 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.