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Optimization of Positron-Lifetime Measurement Geometry Based on Geant4 Simulation

100%

Saro M., Petriska M., Slugeň V.

Acta Physica Polonica A

2017

vol. 132

issue 5

1634-1636

Proper choice of measuring geometry and experimental setup of nuclear instrumentation modules and photomultipliers is a key element which affects substantial positron lifetime measurement properties: count rate and time resolution. An adequate compromise must be found, when it comes to geometry of measurement. The optimal geometry using three detector layout is inspected in this paper. During our work, we concentrated on the simulation of XP2020Q photomultipliers and the BaF₂ scintillator material. The Geant4 simulation allows to estimate an influence of the measuring geometry on detection efficiency and to choose the most appropriate crystals dimensions and positions. As mentioned in paper of Bečvaŕ et al., slight changes in geometry result in distortion or improvement of measured results. Experimental results already showed, changes of start crystals dimensions can result in significant increase in count rate of three-detector measurement.

Investigation of Trace Element Concentration in Diabetic Rat's Tissues

80%

Kowalska J., Krośniak M., Gryboś R., Kwiatek W.

Acta Physica Polonica A

2009

vol. 115

issue 2

556-560

Diabetes is one of the most frequent diseases in developing countries and thus there is a significant interest in diabetes related studies. It was found that vanadium compounds have glucose-lowering properties in diabetes and therefore it is very important to estimate the vanadium dose in diabetes treatment. On the other hand, the proper estimation of vanadium concentration is important due to side effects that occur in vanadium supplementation. In this study the influence of V(IV) and V(V) compounds with different ligands on the concentration of K, Ca, Mn, Fe, Cu, and Zn in selected rat's tissues was investigated by means of proton induced X-ray emission technique. As a result of the measurements it was found that the concentration of vanadium depends on the organ. The highest value was determined in spleen while the lowest in pancreas. It was also found that the concentration of other elements depends on the presence of vanadium and its concentration. The most meaningful influence of vanadium presence was on iron concentration in spleen, on copper and zinc in kidney, and on manganese in pancreas.

At the Tip of an MeV Beam: Provoking Cells and Performing Tomographic Imaging

51%

Pallon J., Arteaga-Marrero N., Nilsson C., Elfman M., Kristiansson P., Nilsson C., Wegdén M., Olsson M., Åkerström B.

Acta Physica Polonica A

2009

vol. 115

issue 2

501-506

Biological applications of ion beams have recently become a new important research field using single ion hit facilities to study individual living cells and their response to the hit of a counted number of ions. One motivation is the search for a better understanding of the fundamental processes taking place in cells and organs as a result of irradiation. Another comes from the increasing interest in using high energy protons and heavy ions as a modality for radiotherapy of deep seated tumours. In the view of treatment efficiency, study of cell culture behaviour under controlled radiation experiments, and in different chemical environments at single ion hit facilities, is a first step towards a better understanding of the processes. Tomographic techniques are applicable to situations where you need information of the inside of an object but do not want to section it into thin slices or cannot do it. Using focused MeV ion beams for tomography restricts the sample size to the order of 10-100 μm, depending of the initial energy. On the other hand, the ability to focus at a sub-micrometer level makes ion beams well suited for analyses of small sized objects as cells, spores, etc. The scanning transmission ion microscopy mode of tomography gives the mass density and corresponding morphological structure of holes and pores. It can then be used to correct the results from the other mode, particle induced X-ray emission tomography. Here is discussed a porosity analysis of bentonite clay that is planned to form an important buffer zone around canisters filled with spent nuclear reactor fuel waste deposited 500 m underground in Sweden.

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3 Acta Physica Polonica A

1 2017

2 2009

1 Arteaga-Marrero N.

1 Elfman M.

1 Gryboś R.

1 Kowalska J.

1 Kristiansson P.

1 Krośniak M.

1 Kwiatek W.

1 Nilsson C.

1 Olsson M.

1 Pallon J.

1 Petriska M.

1 Saro M.

1 Slugeň V.

1 Wegdén M.

1 Åkerström B.

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Optimization of Positron-Lifetime Measurement Geometry Based on Geant4 Simulation

Investigation of Trace Element Concentration in Diabetic Rat's Tissues

At the Tip of an MeV Beam: Provoking Cells and Performing Tomographic Imaging