| 1. |
- Messi, F., et al.
(författare)
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Gamma- and Fast Neutron- Sensitivity of 10B- Based Neutron Detectors at ESS
- 2017
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Ingår i: 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2017 - Conference Proceedings. - 9781538622827
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS), presently under construction in Lund, Sweden, is designed to be the world's brightest neutron source. When it will be in operation, ESS will deliver an instantaneous neutron flux on detectors that will be without precedent. A down side of the high brightness will be the increase of background, especially from gamma-rays and fast-neutrons.Considering that scattering cross-sections of many samples tend to be relatively low and that the gamma- and fast-neutronbackgrounds tend to be considerable high at spallation facilities [Che +14], the signal-to-noise ratio of a measurement needs to be maximised. The sensitivity of a thermal-neutron detector to gamma-rays and to fast-neutrons is a very important characteristic, as it defines the best achievable signal-to-noise ratio for the measurement. It is therefore crucial to measure the gamma- and fast-neutron- sensitivities of all detectors that will be installed on the instruments at ESS.
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| 2. |
- Rana, Rakesh, et al.
(författare)
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Selecting software reliability growth models and improving their predictive accuracy using historical projects data
- 2014
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Ingår i: Journal of Systems and Software. - : Elsevier BV. - 0164-1212 .- 1873-1228. ; 98, s. 59-78
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Tidskriftsartikel (refereegranskat)abstract
- During software development two important decisions organizations have to make are: how to allocate testing resources optimally and when the software is ready for release. SRGMs (software reliability growth models) provide empirical basis for evaluating and predicting reliability of software systems. When using SRGMs for the purpose of optimizing testing resource allocation, the model's ability to accurately predict the expected defect inflow profile is useful. For assessing release readiness, the asymptote accuracy is the most important attribute. Although more than hundred models for software reliability have been proposed and evaluated over time, there exists no clear guide on which models should be used for a given software development process or for a given industrial domain. Using defect inflow profiles from large software projects from Ericsson, Volvo Car Corporation and Saab, we evaluate commonly used SRGMs for their ability to provide empirical basis for making these decisions. We also demonstrate that using defect intensity growth rate from earlier projects increases the accuracy of the predictions. Our results show that Logistic and Gompertz models are the most accurate models; we further observe that classifying a given project based on its expected shape of defect inflow help to select the most appropriate model. (C) 2014 Elsevier Inc. All rights reserved.
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| 3. |
- Tong, M., et al.
(författare)
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An integrated framework for multi-scale multi-physics numerical modelling of interface evolution in welding
- 2012
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Ingår i: IOP Conf. Ser. Mater. Sci. Eng..
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Konferensbidrag (refereegranskat)abstract
- The project Modelling of Interface evolution in advanced Welding (MIntWeld) is a 4-year international research project funded by the European Commission under their FP7 programme. Its main target is to develop a numerical toolbox which can be used to predict the evolution of interfaces during welding. There are various interfaces involving multiple phenomena and different spatial scales, which can be simulated using corresponding numerical modelling methods respectively. The modelling methods include quantum dynamics, molecular dynamics, phase field, phase field crystal, computational fluid dynamics, phase transformation and heat transfer, thermodynamics, continuum mechanics and life and defects prediction. Although each modelling method is based on different physical theories and involves different scales, they are not isolated. Therefore, this project aims to design a common framework which couples each model with the upstream and/or downstream model at the relevant neighbouring length scales. The data exchange framework which underpins the coupling of the models is described, and typical examples addressing the solution to the challenges faced, such as those of data interpolation between one discretisation of the computational domain and another, are discussed. Initial successes from the model-linking efforts of the authors are also presented.
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| 4. |
- Ramos Santesmases, David, et al.
(författare)
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Quasi-3-dimensional simulations and experimental validation of surface leakage currents in high operating temperature type-II superlattice infrared detectors
- 2022
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 132:20, s. 204501-
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Tidskriftsartikel (refereegranskat)abstract
- The surface leakage in InAs/GaSb type-II superlattice (T2SL) is studied experimentally and theoretically for photodiodes with small sizes down to 10 x 10 mu m(2). The dependence of dark current density on mesa size is studied at 110 and 200 K, and surface leakage is shown to impact both generation-recombination (GR) and diffusion dark current mechanisms. A quasi-3-dimensional model to simulate the fabrication process using surface traps on the pixel's sidewall is presented and is used to accurately represent the dark current of large and small pixels with surface leakage in the different temperature regimes. The simulations confirmed that the surface leakage current has a GR and diffusion component at low and high temperature, respectively. Finally, the surface leakage current has been correlated with the change in minority carrier concentration at the surface due to the presence of donor traps.
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