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The Deep Underground Neutrino Experiment (DUNE) is an international research collaboration aimed at exploring topics related to neutrinos and proton decay, which should start collecting data around 2025. In a recent study featured in Physical Review Letters, a team of researchers at Ohio State University have showed that DUNE has the potential to deliver groundbreaking results and insight about solar neutrinos.

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Semiconductors are the basic building blocks of digital devices. Improvements in semiconductor functionality and performance are likewise enabling next-generation applications of semiconductors for computing, sensing and energy conversion. Yet researchers have long struggled with limitations in their ability to fully understand the electronic charges inside semiconductor devices and advanced semiconductor materials, limiting researchers' ability to drive further advances.

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Consistency test of coincidence-summing calculation methods for extended sources

O.Sima, A.De Vismes Ott, M.S.Dias, P.Dryak, L.Ferreux, D.Gurau,  S.Hurtado, P.Jodlowski, K.Karfopoulos, M.F.Koskinas, M.Laubenstein, Y.K.Lee, M.C.Lépy, A.Luca, M.O.Menezes, D.S.Moreira, J.Nikolič, V.Peyres, P.Saganowski, M.I.Savva, R.Semmler, J.Solc, T.T.Thanh, K.Tyminska, Z.Tyminski, T.Vidmar, I.Vukanac, H.Yucel

Abstract:

An internal consistency test of the calculation of coincidence-summing correction factors FC for volume sources is presented. The test is based on exact equations relating the values of FC calculated for three ideal measurement configurations. The test is applied to a number of 33 sets of FC values sent by 21 teams. Most sets passed the test, but not the results obtained using the quasi-point source approximation; in the latter case the test qualitatively indicated the magnitude of the bias of FC.

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Consistent mean-field description of the 12C+12C optical potential at low energies and the astrophysical S factor

Le Hoang Chien, Dao T. Khoa, Do Cong Cuong, and Nguyen Hoang Phuc

Abstract:

The nuclear mean-field potential built up by the 12C+12C interaction at energies relevant for the carbon burning process is calculated in the double-folding model (DFM) using the realistic ground-state density of 12C and the CDM3Y3 density dependent nucleon-nucleon (NN) interaction, with the rearrangement term properly included. To validate the use of a density dependent NN interaction in the DFM calculation in the low-energy regime, an adiabatic approximation is suggested for the nucleus-nucleus overlap density. The reliability of the nuclear mean-field potential predicted by this low-energy version of the DFM is tested in a detailed optical model analysis of the elastic 12C+12C scattering data at energies below 10 MeV/nucleon. The folded mean-field potential is then used to study the astrophysical S factor of 12C+12C fusion in the barrier penetration model. Without any adjustment of the potential strength, our results reproduce very well the nonresonant behavior of the S factor of 12C+12C fusion over a wide range of energies.

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 Mean-field description of heavy-ion scattering at low energies and fusion

Dao T. Khoa, Le Hoang Chien, Do Cong Cuong, Nguyen Hoang Phuc

Abstract:

The nuclear mean-field potential built up during the 12C + 12C and 16O + 16O collisions at low energies relevant for the carbon- and oxygen-burning processes is constructed within the double-folding model (DFM) using the realistic ground-state densities of 12C and 16O, and CDM3Yn density-dependent nucleon–nucleon (NN) inter- action. The rearrangement term, indicated by the Hugenholtz–van Hove theorem for the single-particle energy in nuclear matter, is properly considered in the DFM calculation. To validate the use of the density-dependent NN interaction at low energies, an adiabatic approximation was suggested for the dinuclear overlap density. The reliability of the nucleus–nucleus potential predicted through this low-energy version of the DFM was tested in the optical model (OM) analysis of the elastic 12 C + 12 C and 16 O + 16O scattering data at energies below 10 MeV/nucleon. These OM results provide a consistently good description of the elastic angular distributions and 90 excitation function. The dinuclear mean-field potential predicted by the DFM is further used to determine the astrophysical S factor of the 12C + 12C and 16O + 16O fusions in the barrier penetration model. Without any adjustment of the potential strength, our results reproduce the non-resonant behavior of the S factor of the 12C + 12C and 16O + 16O fusions very well over a wide range of energies.

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Author: Thu T.C.Nguyen, Binh T.Nguyen, Nhon V.Mai

Purpose

Under geometrical uncertainties, different plan evaluation methods have been suggested but the dose distribution at a specified confidence level being highly desirable is lacking. In this work, we used the DVPH (Dose Volume Population Histogram) tool to evaluate the dose distribution of CTVs and OARs (Organs at Risk) and validate the PTV concept at a certain confidence level.

Methods

The plans were evaluated using PTV DVH and the DVPH approach. The DVPH approach is based on statistical analyzing of multiple CTV DVHs under geometrical errors with corresponding occurring probabilities. The random and systematic geometrical errors, assumed to follow a Gaussian distribution, are simulated by shifting the CT images.

Results

For target doses, the results showed that the minimum dose to PTV does not represent the minimum dose to the CTV. For two prostate cases, the minimum doses reduced from 98% and 95% of prescribed dose from PTV DVH to 89% and 92% of prescribed dose from CTV 90% CL-DVPH (90% Confidence Level-DVPH). This reduction was also seen in head and neck cases, from 95% to 68% and 74% of prescribed dose. For OAR doses, OAR DVHs underestimated the OAR dose receiving.

Conclusions

With the DVPH tool, the results showed that the minimum dose to the PTV is not a representative of the minimum dose to the CTV in IMPT at the 90% confidence level. The OAR DVH does not match any OAR CL-DVPHs.

 

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