Elucidating metal oxide growth mechanisms is essential for precisely designing and fabricating nanostructured oxides with broad applications in energy and electronics. However, current epitaxial ...oxide growth methods are based on macroscopic empirical knowledge, lacking fundamental guidance at the nanoscale. Using correlated in situ environmental transmission electron microscopy, statistically-validated quantitative analysis, and density functional theory calculations, we show epitaxial Cu
O nano-island growth on Cu is layer-by-layer along Cu
O(110) planes, regardless of substrate orientation, contradicting classical models that predict multi-layer growth parallel to substrate surfaces. Growth kinetics show cubic relationships with time, indicating individual oxide monolayers follow Frank-van der Merwe growth whereas oxide islands follow Stranski-Krastanov growth. Cu sources for island growth transition from step edges to bulk substrates during oxidation, contrasting with classical corrosion theories which assume subsurface sources predominate. Our results resolve alternative epitaxial island growth mechanisms, improving the understanding of oxidation dynamics critical for advanced manufacturing at the nanoscale.
Hadron detection with a dual-readout fiber calorimeter Lee, S.; Cardini, A.; Cascella, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2017, Letnik:
866, Številka:
C
Journal Article
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In this paper, we describe measurements of the response functions of a fiber-based dual-readout calorimeter for pions, protons and multiparticle “jets” with energies in the range from 20 to 180 GeV. ...The calorimeter uses lead as absorber material and has a total mass of 1350 kg. It is complemented by leakage counters made of scintillating plastic, with a total mass of 500 kg. The effects of these leakage counters on the calorimeter performance are studied as well. In a separate section, we investigate and compare different methods to measure the energy resolution of a calorimeter. Using only the signals provided by the calorimeter, we demonstrate that our dual-readout calorimeter, calibrated with electrons, is able to reconstruct the energy of proton and pion beam particles to within a few percent at all energies. The fractional widths of the signal distributions for these particles (σ∕E) scale with the beam energy as 30%∕E, without any additional contributing terms.
Objective:The study was aimed to evaluate the relationship between pharmacy supply, self-reported treatment adherence and HIV viral load in HIV-infected children.Methods:A retrospective (52 weeks) ...cohort study was conducted through the review of the existing databases. Pharmacy supply was classified as “home delivery” when the medications were delivered home and as “in pharmacy pick-up” when they were picked up at the pharmacy. Adherence was assessed through retrospective (3 days recall) self-report. Fisher’s exact model, univariate and multivariate logistic regression analyses were used.Settings:The study collected data on 140 HIV-infected children (<18 years). Adherence, pharmacy supply information and HIV viral loads were obtained from clinical and research databases.Patients:The data from 127 HIV-infected children (60 boys and 67 girls; mean age 9.9 years) were collected.Main Outcome Measures:Complete adherence (100%) was reported in only 24% of patients. With 40% of patients being rarely or never completely adherent, 64% of children achieved undetectable viral loads during the study period.Results:No association between pharmacy supply and self-reported adherence was found (p = 0.605). Self-reported adherence (p = 0.0328) and age (p = 0.025) were the significant predictors of reaching undetectable viral loads. Adolescents (>13 years) were significantly less likely to reach undetectable viral loads than children under 13 years (odds ratio 0.38; 95% CI 0.16 to 0.89).Conclusion:In our study, pharmacy supply was not associated with self-reported adherence. Most importantly, adherence and age were significant predictors of reaching undetectable viral loads.
The RD52 dual-readout calorimeter is a longitudinally unsegmented instrument intended for the detection of both electromagnetically and hadronically interacting particles with unprecedented ...precision. In this paper, the identification of the showering particles and, in particular, the identification of electrons and gamma s with this instrument are investigated. The techniques used for this purpose include differences in the shower development observed with scintillation light and Cherenkov radiation, the radial shower profile of the particles and the time structure (including the starting point) of the calorimeter signals. It turns out that, at 60 GeV, electrons can be correctly identified in 99.8% of the cases, by means of criteria that eliminate 99.8% of the hadrons.
The small-angle performance of a dual-readout fiber calorimeter Cardini, A.; Cascella, M.; Choi, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2016, Letnik:
808, Številka:
C
Journal Article
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The performance of the RD52 dual-readout calorimeter is measured for very small angles of incidence between the 20GeV electron beam particles and the direction of the fibers that form the active ...elements of this calorimeter. The calorimeter response is observed to be independent of the angle of incidence for both the scintillating and the Čerenkov fibers, whereas significant differences are found between the angular dependence of the energy resolution measured with these two types of fibers. The experimental results are on crucial points at variance with the predictions of GEANT4 Monte Carlo simulations.
The RD52 calorimeter uses the dual-readout principle to detect both electromagnetic and hadronic showers, as well as muons. Scintillation and Cherenkov light provide the two signals which, in ...combination, allow for superior hadronic performance. In this paper, we report on detailed, GEANT4 based Monte Carlo simulations of the performance of this instrument. The results of these simulations are compared in great detail to measurements that have been carried out and published by the DREAM Collaboration. This comparison makes it possible to understand subtle details of the shower development in this unusual particle detector. It also allows for predictions of the improvement in the performance that may be expected for larger detectors of this type. These studies also revealed some inadequacies in the GEANT4 simulation packages, especially for hadronic showers, but also for the Cherenkov signals from electromagnetic showers.
A comparison of BGO and BSO crystals used in the dual-readout mode Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2011, Letnik:
640, Številka:
1
Journal Article
Recenzirano
We report on a systematic study of the properties of two high-
Z scintillating crystals, bismuth germanate (BGO) and bismuth silicate (BSO), in view of the possible application of such crystals in ...dual-readout calorimeters. Whereas the light attenuation characteristics of both crystals are about the same, BSO offers a considerably higher Cherenkov light yield, and with a given UV filter the separation between the Cherenkov and scintillation signals is substantially better in this crystal.
Detection of electron showers in dual-readout crystal calorimeters Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2012, Letnik:
686
Journal Article
Recenzirano
Some high-Z scintillating crystals offer the possibility to distinguish the contributions from the scintillation and Čherenkov mechanisms to the generated signals. Among these crystals are BGO and ...PbWO4. We have tested matrices of these crystals as electromagnetic calorimeters and studied the properties of the Čherenkov and scintillation components of the signals generated by high-energy electrons showering in these detectors.
CDF Run II silicon tracking projects Sill, Alan
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2000, Letnik:
447, Številka:
1
Journal Article
Recenzirano
Design features, functionality, and expected performance are reviewed for the silicon charged particle track detectors to be used by the Collider Detector at Fermilab (CDF) during the upcoming Run II ...of the Fermilab Tevatron. The original design has been supplemented by addiition of a new layer of silicon mounted on the beam pipe that improves the vertexing performance of the combined assembly. Progress has been made in many areas of design and construction of the silicon sensors, readout electronics, and associated systems. The resulting detector array should provide substantial improvements in coverage and performance over those of previous CDF silicon vertex detectors.
New crystals for dual-readout calorimetry Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2009, Letnik:
604, Številka:
3
Journal Article
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Lead tungstate crystals doped with small fractions of praesodynium or molybdenum have been tested in beams of high-energy electrons. The goal of these tests was to study the effects of such dopants ...on the capability to separate the signal components deriving from the Cherenkov and scintillation light generated by the beam particles. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.
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