Full Energy Range Research Articles

On the robustness of IceCube\u2019s bound on sterile neutrinos in the presence of non-standard interactions

The mixing parameters of sterile neutrino(s) preferred by the MiniBooNE and LNSD experiments are in strong tension with the exclusion limit from the IceCube experiment. Recently it has been claimed that by considering the non-standard neutrino interactions (NSI) in addition to the sterile neutrino, the IceCube’s limit can be relaxed and the tension can be reconciled; a baroque scenario as it has been called. We will show that this claim is just an artifact originating from the energy cuts of the chosen datasets. Contrary to the claim, by turning on the NSI and fixing the NSI parameters to the proposed values, not only the IceCube’s limit on sterile neutrino cannot be alleviated, but in fact the tension will be aggravated (or at least keeps its strength). To this aim, an analysis of the IceCube’s atmospheric neutrino data in the full energy range is crucial.

High-energy external defibrillation and transcutaneous pacing during MRI: feasibility and safety

BackgroundRapid application of external defibrillation, a crucial first-line therapy for ventricular fibrillation and cardiac arrest, is currently unavailable in the setting of magnetic resonance imaging (MRI), raising concerns about patient safety during MRI tests and MRI-guided procedures, particularly in patients with cardiovascular diseases. The objective of this study was to examine the feasibility and safety of defibrillation/pacing for the entire range of clinically useful shock energies inside the MRI bore and during scans, using defibrillation/pacing outside the magnet as a control.MethodsExperiments were conducted using a commercial defibrillator (LIFEPAK 20, Physio-Control, Redmond, Washington, USA) with a custom high-voltage, twisted-pair cable with two mounted resonant floating radiofrequency traps to reduce emission from the defibrillator and the MRI scanner. A total of 18 high-energy (200-360 J) defibrillation experiments were conducted in six swine on a 1.5 T MRI scanner outside the magnet bore, inside the bore, and during scanning, using adult and pediatric defibrillation pads. Defibrillation was followed by cardiac pacing (with capture) in a subset of two animals. Monitored signals included: high-fidelity temperature (0.01 °C, 10 samples/sec) under the pads and 12-lead electrocardiogram (ECG) using an MRI-compatible ECG system.ResultsDefibrillation/pacing was successful in all experiments. Temperature was higher during defibrillation inside the bore and during scanning compared with outside the bore, but the differences were small (ΔT: 0.5 and 0.7 °C, p = 0.01 and 0.04, respectively). During scans, temperature after defibrillation tended to be higher for pediatric vs. adult pads (p = 0.08). MR-image quality (signal-to-noise ratio) decreased by ~ 10% when the defibrillator was turned on.ConclusionsOur study demonstrates the feasibility and safety of in-bore defibrillation for the full range of defibrillation energies used in clinical practice, as well as of transcutaneous cardiac pacing inside the MRI bore. Methods for Improving MR-image quality in the presence of a working defibrillator require further study.

Prospects for the study of event-by-event fluctuations at MPD/NICA project

One of the main physics goals of the Multi Purpose Detector (MPD) is to investigate hot and dense baryonic matter in heavy ion collisions at NICA energies to search for the possible critical end point (CEP). Since the location of CEP is not clear the entire accessible region of the QCD phase diagram needs to be explored by scanning the full range of available beam energies. In case of CEP existence it can be observed by abnormal fluctuations of various quantities such as net-proton multiplicity. This task requires excellent particle identification (PID) capability over as large as possible phase space volume. The identification of charged hadrons is achieved at the momenta of 0:1 – 3 GeV/c. The results of hadron identification and preliminary possibility estimation of the study of event-by-event fluctuations at MPD will be presented.

Disentangling multiple high-energy emission components in the Vela X pulsar wind nebula with the Fermi Large Area Telescope

Context. Vela X is a pulsar wind nebula in which two relativistic particle populations with distinct spatial and spectral distributions dominate the emission at different wavelengths. An extended 2° × 3° nebula is seen in radio and GeV gamma rays. An elongated cocoon prevails in X-rays and TeV gamma rays. Aims. We use ~9.5 yr of data from the Fermi Large Area Telescope (LAT) to disentangle gamma-ray emission from the two components in the energy range from 10 GeV to 2 TeV, bridging the gap between previous measurements at GeV and TeV energies. Methods. We determine the morphology of emission associated to Vela X separately at energies <100 and >100 GeV, and compare it to the morphology seen at other wavelengths. Then, we derive the spectral energy distribution of the two gamma-ray components over the full energy range. Results. The best overall fit to the LAT data is provided by the combination of the two components derived at energies <100 and >100 GeV. The first component has a soft spectrum, spectral index 2.19 ± 0.16−0.22+0.05, and extends over a region of radius 1.°36±0.°04, consistent with the size of the radio nebula. The second component has a harder spectrum, spectral index 0.9 ± 0.3−0.1+0.3, and is concentrated over an area of radius 0.°63±0.°03, coincident with the X-ray cocoon that had already been established as accounting for the bulk of the emission at TeV energies. Conclusions. The spectrum measured for the low-energy component corroborates previous evidence for a roll-over of the electron spectrum in the extended radio nebula at energies of a few tens of GeV possibly due to diffusive escape. The high-energy component has a very hard spectrum: if the emission is produced by electrons with a power-law spectrum, the electrons must be uncooled, and there is a hint that their spectrum may be harder than predictions by standard models of Fermi acceleration at relativistic shocks.

Photon Energy Dependent Micro-Raman Spectroscopy with a Continuum Laser Source

We present a method for continuous, photon energy dependent micro Raman spectroscopy. A narrow excitation line is selected from a continuum laser by an acousto-optic tunable filter (AOTF) plus an additional monochromator (MC). Automation of laser, AOTF, MC and tunable long pass filters enables us to continuously scan the wavelength over the full visible range while synchronously acquiring Raman spectra over a photon energy range from 1.85 eV to 2.83 eV. We demonstrate the applicability of our method on a well-studied sample, reduced graphene oxide (rGO), where we measure the Raman scattering over the whole visual range and use the photon energy dependence of the D, G and GS band as verification for the method we present here. We complement this set of data with additional results from a Ti:sapphire laser source, covering the 1.75 to 1.41 eV range. From the full photon energy range of 1.41 to 2.83 eV, we noticed a small deviation from linearity for the dispersion of the D band.

Measurement of the iron spectrum in cosmic rays by VERITAS

We present a new measurement of the energy spectrum of iron nuclei in cosmic rays from 20 to 500 TeV. The measurement makes use of a template-based analysis method, which, for the first time, is applied to the energy reconstruction of iron-induced air showers recorded by the VERITAS array of imaging atmospheric Cherenkov telescopes. The event selection makes use of the direct Cherenkov light which is emitted by charged particles before the first interaction, as well as other parameters related to the shape of the recorded air shower images. The measured spectrum is well described by a power law $\frac{\mathrm{d} F}{\mathrm{d} E}=f_0\cdot \left(\frac{E}{E_0}\right)^{-\gamma}$ over the full energy range, with $\gamma = 2.82 \pm 0.30 \mathrm{(stat.)} ^{+0.24}_{-0.27} \mathrm{(syst.)}$ and $f_0 = \left( 4.82 \pm 0.98 \mathrm{(stat.)}^{+2.12}_{-2.70} \mathrm{(syst.)} \right)\cdot 10^{-7}$m$^{-2}$s$^{-1}$sr$^{-1}$TeV$^{-1}$ at $E_0=50$TeV, with no indication of a cutoff or spectral break. The measured differential flux is compatible with previous results, with improved statistical uncertainty at the highest energies.

Measurement and analysis of theAm241neutron capture cross section at the n_TOF facility at CERN

The Am241(n,γ) cross section has been measured at the n_TOF facility at CERN with the n_TOF BaF2 Total Absorption Calorimeter in the energy range between 0.2 eV and 10 keV. Our results are analyzed as resolved resonances up to 700 eV, allowing a more detailed description of the cross section than in the current evaluations, which contain resolved resonances only up to 150–160 eV. The cross section in the unresolved resonance region is perfectly consistent with the predictions based on the average resonance parameters deduced from the resolved resonances, thus obtaining a consistent description of the cross section in the full neutron energy range under study. Below 20 eV, our results are in reasonable agreement with JEFF-3.2 as well as with the most recent direct measurements of the resonance integral, and differ up to 20–30% with other experimental data. Between 20 eV and 1 keV, the disagreement with other experimental data and evaluations gradually decreases, in general, with the neutron energy. Above 1 keV, we find compatible results with previously existing values.8 MoreReceived 31 January 2018DOI:https://doi.org/10.1103/PhysRevC.97.054616Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNeutron physicsNuclear reactorsRadiative capturePropertiesA ≥ 220Nuclear Physics

High-resolution insight into the competitive adsorption of heavy metals on natural sediment by site energy distribution

Investigating competitive adsorption on river/lake sediments is valuable for understanding the fate and transport of heavy metals. Most studies have studied the adsorption isotherms of competitive heavy metals, which mainly comparing the adsorption information on the same concentration. However, intrinsically, the concentration of each heavy metal on competitive adsorption sites is different, while the adsorption energy is identical. Thus, this paper introduced the site energy distribution theory to increase insight into the competitive adsorption of heavy metals (Cu, Cd and Zn). The site energy distributions of each metal with and without other coexisting heavy metals were obtained. It illustrated that site energy distributions provide much more information than adsorption isotherms through screening of the full energy range. The results showed the superior heavy metal in each site energy area and the influence of competitive metals on the site energy distribution of target heavy metal. Site energy distributions can further help in determining the competitive sites and ratios of coexisting metals. In particular, in the high-energy area, which has great environmental significance, the ratios of heavy metals in the competitive adsorption sites obtained for various competitive systems were as follows: slightly more than 3:1 (Cu-Cd), slightly less than 3:1 (Cu-Zn), slightly more than 1:1 (Cd-Zn), and nearly 7:2:2 (Cu-Cd-Zn). The results from this study are helpful to deeply understand competitive adsorption of heavy metals (Cu, Cd, Zn) on sediment. Therefore, this study was effective in presenting a general pattern for future reference in competitive adsorption studies on sediments.

Fγ: A new observable for photon-hadron discrimination in hybrid air shower events

To search for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. We present a new observable, Fγ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. Fγ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known Xmax observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), Fγ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable Fγ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Furthermore, Fγ complements nicely to Xmax such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.

Efficiency calibrations of HPGe detector for PGNAA system

In this paper, the efficiency of a HPGe detector for a PGNAA system has been determined using the full peak energy of a 152Eu source. The efficiency is affected by the detector-source distance for the full energy range. The Monte Carlo method was used to determine the detector’s dead layer thickness. A comparison of the simulated and the experimental data on the spectra and efficiency curve shows a very good agreement. The combined results of an experimental and calculation efficiency curve provide information about the dead layer thickness of 2.1 mm. It was found that the dead layer has the greatest effect on the detection efficiency of the low energy range.

Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

This paper introduces a novel method to account for quantum disorder effects into the classical drift-diffusion model of semiconductor transport through the localization landscape theory. Quantum confinement and quantum tunneling in the disordered system change dramatically the energy barriers acting on the perpendicular transport of heterostructures. In addition they lead to percolative transport through paths of minimal energy in the 2D landscape of disordered energies of multiple 2D quantum wells. This model solves the carrier dynamics with quantum effects self-consistently and provides a computationally much faster solver when compared with the Schr\"odinger equation resolution. The theory also provides a good approximation to the density of states for the disordered system over the full range of energies required to account for transport at room-temperature. The current-voltage characteristics modeled by 3-D simulation of a full nitride-based light-emitting diode (LED) structure with compositional material fluctuations closely match the experimental behavior of high quality blue LEDs. The model allows also a fine analysis of the quantum effects involved in carrier transport through such complex heterostructures. Finally, details of carrier population and recombination in the different quantum wells are given.

Mazinger, a γ-ray spectrometry system of high efficiency and very low background for paloeoclimate applications

The study of changes in climate on the scale of the entire history of Earth requires absolute dating methods that cover the total time period. 230Th and 234U disequilibria, as well as 231Pa and 235U, have shown as good candidates to provide ages older than 50ky. Therefore, they are the basis for a method that allows extending the 14C dating up to 500ky or even further. The wide variety of samples, their high number and the fact that several radionuclides are needed to obtain samples’ chronology make γ spectrometry to be a suitable technique in this task. However, its low efficiency and high background, therefore, high detection limits in comparison with α spectrometry, need to be improved to become a real alternative in samples with very low activity levels. With this purpose, Mazinger, a new γ spectrometry system based on two HPGe detectors, which are surrounded by active and passive shieldings and placed 12m underground, has been set up in the Ionizing Radiation Laboratory of the University of Salamanca.In this work, the Mazinger's performance is studied at the full energy range useful for natural radionuclides. In composite detectors, energy resolution is a consequence of the electronics adjustments, which have to enable the raw spectra to be summed without resolution worsening. Therefore, the method used to set up electronics and add spectra is described. Detector background is also analysed and compared with the one of a single low-background HPGe detector as a function of the different shielding elements, obtaining gross values of order 10−4cps. Efficiency and figure of merit are obtained for the main natural radionuclides in marine sediments belonging to the Mediterranean MD99-2348 core. Special focus is made on the 230Th determination whose results are compared with the ones provided by α spectrometry.Results show that Mazinger´s performance, in terms of figure of merit, is four times better than the one of a low-level background HPGe detector, specially suited to detect natural radionuclides, being comparable to the performance of α spectrometry in the 230Th determination, which is the radionuclide of lower γ intensity, and doing Mazinger a first class in radiometry of natural radionuclides.

Hadron calorimeter (PSD) with new photo-detectors (MPPC) in NA61 experiment at CERN

The Projectile Spectator Detector (PSD) is a segmented hadron calorimeter used in NA61 experiment (CERN) to determine a collision centrality as well as an event plane orientation in nucleus-nucleus collisions. The main goal of the experiment includes studying the onset of de-confinement and searching for the critical point of strongly interacting matter. It is of crucial importance to have a precise characterization of the event class with the PSD for the analysis of event-by-event observables. The PSD has been already used for centrality selection on trigger level in measurements of Be+Be and Ar+Sc reactions at beam energies 13 − 158 AGeV and Pb+Pb reaction at beam energy 30 AGeV. In 2016, the central modules of PSD have been equipped with new Hamamatsu MPPC silicon photo-detectors in order to extend dynamic range for studying Pb+Pb reaction at the full energy range 13 − 158 AGeV. Results of the PSD response on proton and lead beams are presented.

Energy and angular analysis of ejected electrons (6–26 eV) from the autoionization regions of argon at incident electron energies 505 and 2018 eV*

High resolution ejected electron spectroscopy has been used to investigate a large number of Ar autoionizing states producing ejected electrons in the energy range from 6 to 26 eV at impact electron energies of 505 and 2018 eV and ejection angles of 40°, 90° and 130°. The full energy range has been divided into three regions which were analyzed separately. In the first one (6–9 eV) the obtained features are identified as the decay of the Ar2+(1D) at 45.11 eV. In the second one (9–14 eV) all features are identified as due to the decay of excited states formed by the excitation of 3s electrons to ns, np and nd subshells. The most prominent features are those arising from the excitation of 3s to nd(3,1D). In this series the 3s3p 63d(1D) state with FWHM of 0.040 eV is used as the calibration point for all measured spectra. In the third energy region (14–26 eV) a large number of features is observed. Most of them are identified as the decay of excited states of the type 3s3p 5 nl and 3s 23p 4 nl n′l′.

MIMAC low energy electron-recoil discrimination measured with fast neutrons

MIMAC (MIcro-TPC MAtrix of Chambers) is a directional WIMP Dark Matter detector project. Direct dark matter experiments need a high level of electron/recoil discrimination to search for nuclear recoils produced by WIMP-nucleus elastic scattering. In this paper, we proposed an original method for electron event rejection based on a multivariate analysis applied to experimental data acquired using monochromatic neutron fields. This analysis shows that a 105 rejection power is reachable for electron/recoil discrimination. Moreover, the efficiency was estimated by a Monte-Carlo simulation showing that a 105 electron rejection power is reached with a 86.49 ± 0.17% nuclear recoil efficiency considering the full energy range and 94.67 ± 0.19% considering a 5 keV lower threshold.

Perspectives of anisotropic flow measurements at NICA

High-accuracy and high-luminosity measurements of anisotropic flow for various hadron types over full NICA energy range will provide important constraints on the early dynamics of heavy-ion reactions under the conditions where a first-order quark-hadron phase transition may occur. The statistical reach for elliptic flow measurements at NICA is estimated with HYDJET++ heavy-ion event generator.

THE THIRD FERMI GBM GAMMA-RAY BURST CATALOG: THE FIRST SIX YEARS

ABSTRACT Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has triggered and located on average approximately two γ-ray bursts (GRBs) every three days. Here, we present the third of a series of catalogs of GRBs detected by GBM, extending the second catalog by two more years through the middle of 2014 July. The resulting list includes 1405 triggers identified as GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM-detected GRBs. For each GRB, the location and main characteristics of the prompt emission, the duration, peak flux, and fluence are derived. The latter two quantities are calculated for the 50–300 keV energy band where the maximum energy release of GRBs in the instrument reference system is observed, and also for a broader energy band from 10 to 1000 keV, exploiting the full energy range of GBM's low-energy [Nai[Tl)] detectors. Using statistical methods to assess clustering, we find that the hardness and duration of GRBs are better fit by a two-component model with short-hard and long-soft bursts than by a model with three components. Furthermore, information is provided on the settings and modifications of the triggering criteria and exceptional operational conditions during years five and six in the mission. This third catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay.

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Obtaining a full range of surface energies on single wall carbon nanotube samples through photo-initiated chemical vapor deposition

Event Abstract Back to Event Obtaining a full range of surface energies on single wall carbon nanotube samples through photo-initiated chemical vapor deposition Seyedehsan Hosseininasab1, Nathalie Faucheux2, Gervais Soucy2 and Jason R. Tavares1 1 Polytechnique Montreal, Chemical engineering, Canada 2 Université de Sherbrooke, Chemical and Biotechnological Engineering, Canada Introduction: Despite all the distinctive properties of carbon nanotubes (CNTs), their commercial use in biomedical applications is limited by their cytotoxicity [1]. Several factors can explain the CNT cytotoxicity including their dimension, surface hydrophobicity and degree of agglomeration [1],[2]. However, the effect of surface energy on the cytotoxicity of single wall carbon nanotubes (SWCNTs) has to be investigated further. For this purpose, well-characterized SWCNTs bearing similar functionalities with properties ranging from super-hydrophobic to super-hydrophilic must be prepared. In this study, photo-initiated chemical vapor deposition (PICVD) using a syngas precursor [3] was applied to SWCNTs and is presented as a viable technique to fulfill this goal. Materials and Methods: Raw-SWCNTs (R-SWCNTs) were first purified by a multi-step protocol as previously described [4]. Efficiency of purification was assessed by transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). These purified SWCNTs (P-SWCNT) were then dispersed in ethanol via sonication and immediately filtered under vacuum upon a polycarbonate membrane. The resulting “buckypaper” was placed in a vacuum oven to ensure complete ethanol evaporation. The surface of SWCNTs was then treated according to a method developed by Dorval Dion et al (2014) [3]. Briefly, P-SWCNTs were placed inside a UVC-illuminated quartz micro-reactor. After inert gas purging, the syngas precursor (CO and H2) was introduced at various ratios along with H2O2 as a radical photo-initiator (PI). To obtain the desired surface functionality, the process could be implemented under pressure (+15 kPag) or slight vacuum (-15 kPag). Hydrophilic surfaces were typically obtained under slight vacuum, while hydrophobic surfaces were achieved under pressure [3]. The surface energy of the treated P-SWCNTs was determined by applying the Owens-Wendt model [5]. Results and Discussion: TEM was used to both confirm the efficiency of the purification protocol and assess the morphology of P-SWCNTs after treatment. As shown Fig. 1A, the impurities in R-SWCNTs included amorphous and graphitic carbon, as well as catalytic metal nanoparticles, while these impurities in P-SWCNTs were decreased (Fig. 1B) (from 29% to 14% based on TGA results). Surface wetting of SWCNT samples was assessed through sessile drop contact angle measurements. The average contact angle of P-SWCNT samples was 79±2°, while it varied from 0+3° to 165±3° for treated nanotubes (T-SWCNTs) as a function of the molar ratio of H2/CO (Fig. 2). Conclusion: Using PICVD with a syngas precursor, we successfully functionalized P-SWCNTs bearing various oxygen-containing groups with properties ranging from superhydrophilic to superhydrophobic. This PICVD method will be helpful to better determine the effect of surface energy on the cytotoxicity of SWCNTs bearing similar functionalities. Fig. 1. TEM images of A) R-SWCNTs, B) P-SWCNTs. Fig. 2. Blue lozenge) Contact angle measurements of T-SWCNTs obtained by tensiometry in terms of molar ratio of H2/CO, Red Square) Surface energy measurements that have been plotted in terms of molar ratio. This project is supported by FRQNT Foundation

Determination of X-ray excitation spectra in micro X-ray fluorescence spectrometry with capillary optics

The quantitative X-ray fluorescence microanalysis by fundamental parameters requires the knowledge of the energy distribution of the excitation beam. When this beam is produced by capillary optics, its high intensity and anisotropy complicate a direct determination. An alternative is an indirect determination based on measurement of induced X-ray fluorescence in a set of targets. In this work the X-ray excitation spectrum is determined by an iterative deconvolution process of the fundamental parameter expression for the X-ray fluorescence intensities. The method has the advantage that it does not require any assumption about the energy distribution of the X-ray source or the energy dependence of the lens transmission. Numerous XRF targets of pure elements with emission lines covering the full energy range of the X-ray source are employed. The only requirement on the targets is a high homogeneity in its composition. In fact, it does not impose any condition on the sample thickness. The accuracy observed in the validation process implemented with reference materials is similar to that reported with alternative approaches: 5% for main components, 10% for minor elements and 15% for trace elements.