| 1. |
- Aaron, F. D., et al.
(författare)
-
Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
-
Tidskriftsartikel (refereegranskat)abstract
- A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy root s = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q(2) < 200 GeV2 in photon virtuality, 0.00035 < x(P) < 0.09 in proton fractional momentum loss, 0.09 < vertical bar t vertical bar < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/x(P), where x is the Bjorken scaling variable.
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| 2. |
- Abramowicz, H., et al.
(författare)
-
Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA
- 2013
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:2
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 <= Q(2) <= 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) <= x <= 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.
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| 3. |
- Aaron, F. D., et al.
(författare)
-
Measurement of D*(+/-) meson production and determination of F-2(c(c)over-bar) at low Q(2) in deep-inelastic scattering at HERA
- 2011
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:10
-
Tidskriftsartikel (refereegranskat)abstract
- Inclusive production of D* mesons in deep-inelastic ep scattering at HERA is studied in the range 5 < Q(2) < 100 GeV2 of the photon virtuality and 0.02 < y < 0.7 of the inelasticity of the scattering process. The observed phase space for the D* meson is (pT) (D*) > 1.25 GeV and |eta( D*)| < 1.8. The data sample corresponds to an integrated luminosity of 348 pb(-1) collected with the H1 detector. Single and double differential cross sections are measured and the charm contribution F-2(c (c) over bar) to the proton structure function F-2 is determined. The results are compared to perturbative QCD predictions at next-to-leading order implementing different schemes for the charm mass treatment and with Monte Carlo models based on leading order matrix elements with parton showers.
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| 4. |
- Aaron, F. D., et al.
(författare)
-
Measurement of dijet production in diffractive deep-inelastic scattering with a leading proton at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:4
-
Tidskriftsartikel (refereegranskat)abstract
- The cross section of diffractive deep-inelastic scattering ep -> eXp is measured, where the system X contains at least two jets and the leading final state proton is detected in the H1 Forward Proton Spectrometer. The measurement is performed for fractional proton longitudinal momentum loss x(P) < 0.1 and covers the range 0.1 < vertical bar t vertical bar < 0.7 GeV2 in squared four-momentum transfer at the proton vertex and 4 < Q(2) < 110 GeV2 in photon virtuality. The differential cross sections extrapolated to vertical bar t vertical bar < 1 GeV2 are in agreement with next-to-leading order QCD predictions based on diffractive parton distribution functions extracted from measurements of inclusive and dijet cross sections in diffractive deep-inelastic scattering. The data are also compared with leading order Monte Carlo models.
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| 5. |
- Aaron, F. D., et al.
(författare)
-
Measurement of photon production in the very forward direction in deep-inelastic scattering at HERA
- 2011
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:10
-
Tidskriftsartikel (refereegranskat)abstract
- The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb(-1). The analysis covers the range of negative four momentum transfer squared at the positron vertex 6 < Q(2) < 100 GeV2 and inelasticity 0.05 < y < 0.6. Cross sections are measured for the most energetic photon with pseudorapidity eta > 7.9 as a function of its transverse momentum p(T)(lead) and longitudinal momentum fraction of the incoming proton x(L)(lead). In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x(L)(sum) L of all photons in the pseudorapidity range. > 7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays.
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| 6. |
- Aaron, F. D., et al.
(författare)
-
Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:3
-
Tidskriftsartikel (refereegranskat)abstract
- Deep-inelastic positron-proton scattering events at low photon virtuality, Q(2), with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples, differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Delta phi, between the forward jet and the scattered positron in bins of the rapidity distance, Y, between them. The data are compared to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations in order to test the sensitivity to QCD evolution mechanisms.
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| 7. |
- Aaron, F. D., et al.
(författare)
-
Measurement of the diffractive longitudinal structure function F(L)(D) at HERA
- 2011
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:12
-
Tidskriftsartikel (refereegranskat)abstract
- First measurements are presented of the diffractive cross section sigma(ep) -> eXY at centre-of-mass energies root s of 225 and 252 GeV, together with a precise new measurement at root s of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at root s of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function F(L)(D) in the range of photon virtualities 4.0 <= Q(2) <= 44.0 GeV(2) and fractional proton longitudinal momentum loss 5 x 10(-4) <= x(P) <= 3 x 10(-3). The measured F(L)(D) is compared with leading twist predictions based on diffractive parton densities extracted in NLO QCD fits to previous measurements of diffractive Deep-Inelastic Scattering and with a model which additionally includes a higher twist contribution derived from a colour dipole approach. The ratio of the diffractive cross section induced by longitudinally polarised photons to that for transversely polarised photons is extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.
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| 8. |
- Aaron, F. D., et al.
(författare)
-
Measurement of the inclusive e(+/-) p scattering cross section at high inelasticity y and of the structure function F-L
- 2011
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:3
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement is presented of the inclusive neutral current e(+/-) p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies E-p of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV2 < Q(2) < 120 GeV2, small values of Bjorken x, 2.9 . 10(-5) < x < 0.01, and extends to high inelasticity up to y = 0.85. The structure function F-L is measured by combining the new results with previously published H1 data at E-p = 920 GeV and E-p = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q(2) and low x kinematic domain.
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| 9. |
- Aaron, F. D., et al.
(författare)
-
Search for contact interactions in e(+/-)p collisions at HERA H1 Collaboration
- 2011
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 705:1-2, s. 52-58
-
Tidskriftsartikel (refereegranskat)abstract
- A search for physics beyond the Standard Model in neutral current deep inelastic scattering at high negative four-momentum transfer squared Q(2) is performed in e(+/-)p collisions at HERA. The differential cross section d sigma/dQ(2), measured using the full H1 data sample corresponding to an integrated luminosity of 446 pb(-1), is compared to the Standard Model prediction. No significant deviation is observed. Limits on various models predicting new phenomena at high Q(2) are derived. For general four-fermion eeqq contact interaction models, lower limits on the compositeness scale A are set in the range 3.6 TeV to 7.2 TeV. Leptoquarks with masses M-LQ and couplings lambda are constrained to M-LQ/lambda > 0.41-1.86 TeV and limits on squarks in R-parity violating supersymmetric models are derived. A lower limit on the gravitational scale in 4 + n dimensions of M-S > 0.9 TeV is established for low-scale quantum gravity effects in models with large extra dimensions. For the light quark radius an upper bound of R-q < 0.65 . 10(-18) m is determined. (C) 2011 Elsevier B.V. All rights reserved.
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| 10. |
- Abdellaoui, G., et al.
(författare)
-
Meteor studies in the framework of the JEM-EUSO program
- 2017
-
Ingår i: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 143, s. 245-255
-
Tidskriftsartikel (refereegranskat)abstract
- We summarize the state of the art of a program of UV observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large FOV and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the ISS itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA.
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| 11. |
- Aaron, F. D., et al.
(författare)
-
Inclusive deep inelastic scattering at high Q(2) with longitudinally polarised lepton beams at HERA
- 2012
-
Ingår i: Journal of High Energy Physics. - 1029-8479. ; :9
-
Tidskriftsartikel (refereegranskat)abstract
- Inclusive e(+/-)p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of root s = 319 GeV with a total integrated luminosity of 333.7 pb(-1) shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q(2), between 60 and 50 000GeV(2), and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF(3)(gamma Z). A measurement of the neutral current parity violating structure function F-2(gamma Z) is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.
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| 12. |
- Aaron, F. D., et al.
(författare)
-
Inclusive measurement of diffractive deep-inelastic scattering at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:7
-
Tidskriftsartikel (refereegranskat)abstract
- The diffractive process ep -> eXY, where Y denotes a proton or its low mass excitation with M-Y < 1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3 <= Q(2) <= 1600 GeV2, the square of the fourmomentum transfer at the proton vertex vertical bar t vertical bar < 1.0 GeV2 and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x(P) < 0.05. Triple differential cross sections are measured as a function of x(P), Q(2) and beta = x/x(P) where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested.
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| 13. |
- Aaron, F. D., et al.
(författare)
-
Measurement of beauty photoproduction near threshold using di-electron events with the H1 detector at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
-
Tidskriftsartikel (refereegranskat)abstract
- The cross section for ep -> eb (b) over barX in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b (b) over bar -> eeX' is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q(2) <= 1 GeV2, the inelasticity 0.05 <= y <= 0.65 and the pseudorapidity of the b-quarks vertical bar eta(b)vertical bar, vertical bar eta((b) over bar)vertical bar <= 2. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks < P-T(b)> down to the threshold. The results are compared to next-to-leading-order QCD predictions.
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| 14. |
- Aaron, F. D., et al.
(författare)
-
Measurement of inclusive and dijet D* meson cross sections in photoproduction at HERA
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:5
-
Tidskriftsartikel (refereegranskat)abstract
- The inclusive photoproduction of D* mesons and of D*-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q(2) < 2 GeV2 and photon-proton centre-of-mass energies of 100< W-gamma p < 285 GeV. Inclusive D* meson differential cross sections are measured for central rapidities vertical bar eta(D*)vertical bar < 1.5 and transverse momenta p(T) (D*) > 1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum p(T) (jet) > 3.5 GeV each, one containing the D* meson. Differential cross sections for D*-tagged dijet production and for correlations between the jets are measured in the range vertical bar eta(D*)vertical bar < 1.5 and p(T) (D*) > 2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations.
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| 15. |
- Abdellaoui, G., et al.
(författare)
-
First observations of speed of light tracks by a fluorescence detector looking down on the atmosphere
- 2018
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25(th) of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.
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| 16. |
- Alexa, C., et al.
(författare)
-
Elastic and proton-dissociative photoproduction of J/psi mesons at HERA
- 2013
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:6
-
Tidskriftsartikel (refereegranskat)abstract
- Cross sections for elastic and proton-dissociative photoproduction of J/psi mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies root s approximate to 318 GeV and root s approximate to 225 GeV, corresponding to integrated luminosities of L = 130 pb(-1) and L = 10.8 pb(-1), respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25 < W-gamma p < 110 GeV. Differential cross sections d sigma/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range vertical bar t vertical bar < 1.2 GeV2 for the elastic process and vertical bar t vertical bar < 8 GeV2 for proton dissociation. The results are compared to other measurements. The W-gamma p and t-dependences are parametrised using phenomenological fits.
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| 17. |
- Alexa, C., et al.
(författare)
-
Measurement of charged particle spectra in deep-inelastic ep scattering at HERA
- 2013
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:4
-
Tidskriftsartikel (refereegranskat)abstract
- Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q(2) < 100 GeV2, and small values of Bjorken-x, 10(-4) < x < 10(-2). The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity (n(*)) and transverse momentum (p(T)(*)) in the range 0 < n(*) < 5 and 0 < p(T)(*) < 10 GeV in bins of x and Q(2). The data are compared to predictions from different Monte Carlo generators implementing various options for hadronisation and parton evolutions.
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| 18. |
- Aaron, F. D., et al.
(författare)
-
Determination of the integrated luminosity at HERA using elastic QED Compton events
- 2012
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep -> e gamma p. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.
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| 19. |
- Aaron, F. D., et al.
(författare)
-
Search for lepton flavour violation at HERA
- 2011
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 701:1, s. 20-30
-
Tidskriftsartikel (refereegranskat)abstract
- A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep -> mu X and ep -> tau X is performed by the H1 experiment at HERA. The full data sample taken at a centre-of-mass energy root s = 319 GeV is used for the analysis, corresponding to an integrated luminosity of 245 pb(-1) of e(+)p and 166 pb(-1) of e(-)p collision data. No evidence for the production of such leptoquarks is observed in the H1 data. Leptoquarks produced in e(+/-)p collisions with a coupling strength of lambda = 0.3 and decaying with the same coupling strength to a muon-quark pair or a tau-quark pair are excluded at 95% confidence level up to leptoquark masses of 712 GeV and 479 GeV, respectively. (C) 2011 Elsevier B.V. All rights reserved.
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| 20. |
- Aaron, F. D., et al.
(författare)
-
Search for first generation leptoquarks in ep collisions at HERA
- 2011
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 704:5, s. 388-396
-
Tidskriftsartikel (refereegranskat)abstract
- A search for first generation scalar and vector leptoquarks produced in ep collisions is performed by the H1 experiment at HERA. The full H1 data sample is used in the analysis, corresponding to an integrated luminosity of 446 pb(-1). No evidence for the production of leptoquarks is observed in final states with a large transverse momentum electron or with large missing transverse momentum, and constraints on leptoquark models are derived. For leptoquark couplings of electromagnetic strength lambda = 0.3, first generation leptoquarks with masses up to 800 GeV are excluded at 95% confidence level. (C) 2011 Elsevier B.V. All rights reserved.
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| 21. |
- Ariga, T., et al.
(författare)
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Measuring GBAR with emulsion detector
- 2014
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Ingår i: International Journal of Modern Physics, Conference Series. - : World Scientific. - 2010-1945. ; 30
-
Tidskriftsartikel (refereegranskat)
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| 22. |
- Aghion, S., et al.
(författare)
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A moiré deflectometer for antimatter
- 2014
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics—the moiré deflectometer—for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.
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| 23. |
- Barrillon, P., et al.
(författare)
-
The EUSO@TurLab project in the framework of the JEM-EUSO program
- 2023
-
Ingår i: Experimental astronomy. - : Springer Nature. - 0922-6435 .- 1572-9508. ; 55:2, s. 569-602
-
Tidskriftsartikel (refereegranskat)abstract
- The EUSO@TurLab project aims at performing experiments to reproduce Earth UV emissions as seen from a low Earth orbit by the planned missions of the JEM-EUSO program. It makes use of the TurLab facility, which is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located at the Physics Department of the University of Turin. All the experiments are designed and performed based on simulations of the expected response of the detectors to be flown in space. In April 2016 the TUS detector and more recently in October 2019 the Mini-EUSO experiment, both part of the JEM-EUSO program, have been placed in orbit to map the UV Earth emissions. It is, therefore, now possible to compare the replicas performed at TurLab with the actual images detected in space to understand the level of fidelity in terms of reproduction of the expected signals. We show that the laboratory tests reproduce at the order of magnitude level the measurements from space in terms of spatial extension and time duration of the emitted UV light, as well as the intensity in terms of expected counts per pixel per unit time when atmospheric transient events, diffuse nightlow background light, and artificial light sources are considered. Therefore, TurLab is found to be a very useful facility for testing the acquisition logic of the detectors of the present and future missions of the JEM-EUSO program and beyond in order to reproduce atmospheric signals in the laboratory.
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| 24. |
- Alwall, J., et al.
(författare)
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A standard format for Les Houches Event Files
- 2007
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Ingår i: Computer Physics Communications. - : Elsevier BV. - 0010-4655. ; 176:4, s. 300-304
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Tidskriftsartikel (refereegranskat)abstract
- A standard file format is proposed to store process and event information, primarily output from partoti-level event generators for further use by general-purpose ones. The information content is identical with what was already defined by the Les Houches Accord five years ago, but then in terms of Fortran commonblocks. This information is embedded in a minimal XML-style structure, for clarity and to simplify parsing.
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| 25. |
- Bisconti, F, et al.
(författare)
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Mini-EUSO engineering model : Tests in open-sky condition
- 2019
-
Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a UV telescope that will look downwards to the Earth’s atmosphere onboard the International Space Station. With the design of the ultra-high energy cosmic ray fluorescence detectors belonging to the JEM-EUSO program, it will make the first UV map of the Earth by observing atmospheric phenomena such as transient luminous events, sprites and lightning, as well as meteors and bioluminescence from earth. Diffused light from laser shots from the ground, which mimic the fluorescence light emitted by Nitrogen molecules when extensive air showers pass through the atmosphere, can be used to verify the capability of this kind of detector to observe ultra-high energy cosmic rays. To validate the electronics and the trigger algorithms developed for Mini-EUSO, a scaled down version of the telescope with 1:9 of the original focal surface and a lens of 2.5 cm diameter has been built. Tests of the Mini-EUSO engineering model have been made in laboratory and in open sky condition. In this paper, we report results of observations of the night sky, which include the detection of stars, meteors, a planet and a rocket body reflecting the sunlight. Interesting results of the observation of city lights are also reported.
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| 26. |
- Casolino, M, et al.
(författare)
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Mini-EUSO experiment to study UV emission of terrestrial and astrophysical origin onboard of the International Space Station
- 2019
-
Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO will observe the Earth in the UV range (300 - 400 nm) offering the opportunity to study a variety of atmospheric events such as Transient Luminous Events (TLEs), meteors and marine bioluminescence. Furthermore it aims to search for Ultra High Energy Cosmic Rays (UHECR) above 1021 eV and Strange Quark Matter (SQM). The detector is expected to be launched to the International Space Station in August 2019 and look at the Earth in nadir mode from the UV-transparent window of the Zvezda module of the International Space Station. The instrument comprises a compact telescope with a large field of view (44?), based on an optical system employing two Fresnel lenses for light collection. The light is focused onto an array of 36 multi-anode photomultiplier tubes (MAPMT), for a total of 2304 pixels and the resulting signal is converted into digital, processed and stored via the electronics subsystems on-board. In addition to the main detector, Mini-EUSO contains two ancillary cameras[4] for complementary measurements in the near infrared (1500 - 1600 nm) and visible (400 - 780 nm) range and also a 8 × 8 SiPM imaging array.
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| 27. |
- Marcelli, L., et al.
(författare)
-
Integration, qualification, and launch of the Mini-EUSO telescope on board the ISS
- 2023
-
Ingår i: Rendiconti Lincei SCIENZE FISICHE E NATURALI. - : Springer Nature. - 2037-4631 .- 1720-0776. ; 34:1, s. 23-35
-
Tidskriftsartikel (refereegranskat)abstract
- Mini-EUSO is a high-sensitivity imaging telescope that observes the Earth from the ISS in the near ultraviolet band (290÷ 430 nm), through the nadir-facing, UV-transparent window in the Russian Zvezda module. The instrument, launched in 2019, has a field of view of 44∘, a spatial resolution on the Earth’s surface of 6.3 km and a temporal sampling rate of 2.5 microseconds. Thanks to its triggering and on-board processing, the telescope is capable of detecting UV emissions of cosmic, atmospheric, and terrestrial origin on different time scales, from a few microseconds up to tens of milliseconds. The optics is composed of two Fresnel lenses focusing light onto an array of 36 Hamamatsu Multi-Anode PhotoMultiplier Tubes, for a total of 2304 pixels. The telescope also contains two cameras in the near-infrared and visible, an 8-by-8 array of Silicon-PhotoMultipliers and a series of UV sensors to manage night-day transitions. The scientific objectives range from the observation of atmospheric phenomena [lightning, Transient Luminous Events (TLEs), ELVES], the study of meteoroids, the search of interstellar meteoroids and strange quark matter, mapping of the Earth’s nocturnal emissions in the ultraviolet range, and the search of cosmic rays with energy above 1021 eV. The instrument has been integrated and qualified in 2019, with the final tests in Baikonur prior to its launch. Operations involve periodic installation in the Zvezda module of the station with observations during the crew night time, with periodic downlink of data samples, with the full data being sent to the ground via pouches containing the data disks. Mission planning involves the selection of the optimal orbits to maximize the scientific return of the instrument. In this work, we will describe the various phases of construction, testing, and qualification prior to the launch and the in-flight operations of the instrument on board the ISS.
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| 28. |
- Miyamoto, H, et al.
(författare)
-
Space debris detection and tracking with the techniques of cosmic ray physics
- 2019
-
Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Space Debris (SD) consist of non-operational artificial objects orbiting around the Earth, which could possibly damage space vehicles, such as the International Space Station (ISS) or other manned spacecrafts. The vast majority of such objects are cm-sized, not catalogued and usually the tracking data are not precise enough. Here we present the feasibility study of SD detection and tracking with techniques usually employed in cosmic-ray physics. For this purpose, we have evaluated the possibility of using Mini-EUSO, a space-borne fluorescence telescope to be deployed on the ISS, to track SD illuminated by the Sun. By means of ESAF (EUSO Simulation and analysis Framework) simulation and by developing the trigger algorithms, we estimated the minimum size and maximum distances of detectable SD. We then studied the number of possible SD detections using an ESA software called MASTER (Meteoroid and SD Terrestrial Environment Reference). With the Mini-EUSO Engineering Model (Mini-EUSO EM), we performed some measurements to estimate the reflectance of the most common SD materials and to demonstrate the ability of Mini-EUSO to detect SD events. We also performed some tests in open-sky conditions, identifying and tracking fast-moving objects. In particular, the detection of a rocket body allowed us to confirm the simulation outcomes predictions and the expected performance of the detector.
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| 29. |
- Miyamoto, H., et al.
(författare)
-
The Euso@turlab : Test of mini-EUSO engineering model
- 2019
-
Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- The TurLab facility is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located in the Physics Department of the University of Turin. Originally, it was mainly built to study systems of different scales where rotation plays a key role in the fluid behavior such as in atmospheric and oceanic flows. In the past few years the TurLab facility has been used to perform experiments related to the observation of Extreme Energy Cosmic Rays (EECRs) from space using the fluorescence technique. For example, in the case of the JEM-EUSO mission, where the diffuse night brightness and artificial light sources can vary significantly in time and space inside the Field of View of the telescope. The Focal Surface of Mini-EUSO Engineering Model (Mini-EUSO EM) with the level 1 (L1) and 2 (L2) trigger logics implemented in the Photo-Detector Module (PDM) has been tested at TurLab. Tests related to the possibility of using an EUSO-like detector for other type of applications such as Space Debris (SD) monitoring and imaging detector have also been pursued. The tests and results obtained within the EUSO@TurLab Project on these different topics are presented.
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| 30. |
- Bisconti, F., et al.
(författare)
-
Pre-flight qualification tests of the Mini-EUSO telescope engineering model
- 2022
-
Ingår i: Experimental astronomy. - : Springer Nature. - 0922-6435 .- 1572-9508. ; 53:1, s. 133-158
-
Tidskriftsartikel (refereegranskat)abstract
- Mini-EUSO is part of the JEM-EUSO program and operates on board the International Space Station (ISS). It is a UV-telescope with single-photon counting capability looking at nighttime downwards to the Earth through a nadir-facing UV-transparent window. As part of the pre-flight tests, the Mini-EUSO engineering model, a telescope with 1/9 of the original focal surface and a lens of 2.5 cm diameter, has been built and tested. Tests of the Mini-EUSO engineering model have been made in laboratory and in open-sky conditions. Laboratory tests have been performed at the TurLab facility, located at the Physics Department of the University of Turin, equipped with a rotating tank containing different types of materials and light sources. In this way, the configuration for the observation of the Earth from space was emulated, including the Mini-EUSO trigger schemes. In addition to the qualification and calibration tests, the Mini-EUSO engineering model has also been used to evaluate the possibility of using a JEM-EUSO-type detector for applications such as observation of space debris. Furthermore, observations in open-sky conditions allowed the studies of natural light sources such as stars, meteors, planets, and artificial light sources such as airplanes, satellites reflecting the sunlight, and city lights. Most of these targets could be detected also with Mini-EUSO. In this paper, the tests in laboratory and in open-sky conditions are reported, as well as the obtained results. In addition, the contribution that such tests provided to foresee and improve the performance of Mini-EUSO on board the ISS is discussed.
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| 31. |
- Bykova, E., et al.
(författare)
-
Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts
- 2018
-
Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Paulings rule, are connected through common faces. Our results suggest that possible silicate liquids in Earths lower mantle may have complex structures making them more compressible than previously supposed.
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| 32. |
- Cambié, G., et al.
(författare)
-
Integration and qualification of the Mini-EUSO telescope on board the ISS
- 2022
-
Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a compact telescope (37 × 37 × 62 cm3) currently hosted on board the International Space Station. Mini-EUSO is devoted primarily to study Ultra High Energy Cosmic Rays (UHECR) above 1021 eV but also to search for Strange Quark Matter (SQM), to observe Transient Luminous Event (TLE) in upper atmosphere, meteoroids, sea bioluminescence and space debris tracking. Mini-EUSO consist of a main optical system, the Photo Detector Module (PDM), sensitive to UV spectrum (300 ÷ 400 nm) and several ancillary sensors comprising a visible (400 ÷ 780 nm) and NIR (1500 ÷ 1600 nm) cameras and a 8 × 8 channels Multi-Pixel Photon Counter Silicon PhotoMultiplier (MPPC SiPM) array which will increase the Tecnological Readyness Level of this ultrafast imaging sensor. Mini-EUSO belongs to a novel set of missions committed to evaluate, for the first time, the capability of observing Cosmic Rays from a space-based The instrumentation, space-qualified tests will be shown.
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| 33. |
- Casolino, M., et al.
(författare)
-
Science of Mini-EUSO detector on board the International Space Station
- 2017
-
Ingår i: Proceedings of Science. - Trieste, Italy : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- The Mini-EUSO space experiment ("UV atmosphere" in Russian Space Program) is a telescope designed to perform observations of night-time Earth in the UV spectrum. The instrument comprises a compact telescope with a large field of view (44°x44°), based on an optical system employing two 25 cm diameter Fresnel lenses (focal length ∼ 30 cm) for increased light collection. Mini-EUSO will study different scientific phenomena ranging from strange quark matter and Ultra High Energy Cosmic Rays (UHECRs) to bioluminescence and atmospheric physics. It will also create the first night-time map of the Earth in UV light. The mission will raise the technology readiness level (TRL) of the future JEM-EUSO missions to observe UHECRs from space. The Mini-EUSO measurements will be performed from the ISS through a UV transparent window in the Russian Zvezda Service Module. Launch is foreseen between Autumn 2017 and beginning 2018 in the framework of the next manned ASI (Italian Space Agency) flight and observations are supposed to continue with Russian cosmonauts for several years.
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| 34. |
- Kowal, Paul, et al.
(författare)
-
Data resource profile : the World Health Organization Study on global AGEing and adult health (SAGE)
- 2012
-
Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 41:6, s. 1639-1649
-
Tidskriftsartikel (refereegranskat)abstract
- Population ageing is rapidly becoming a global issue and will have a major impact on health policies and programmes. The World Health Organization's Study on global AGEing and adult health (SAGE) aims to address the gap in reliable data and scientific knowledge on ageing and health in low- and middle-income countries. SAGE is a longitudinal study with nationally representative samples of persons aged 50+ years in China, Ghana, India, Mexico, Russia and South Africa, with a smaller sample of adults aged 18-49 years in each country for comparisons. Instruments are compatible with other large high-income country longitudinal ageing studies. Wave 1 was conducted during 2007-2010 and included a total of 34 124 respondents aged 50+ and 8340 aged 18-49. In four countries, a subsample consisting of 8160 respondents participated in Wave 1 and the 2002/04 World Health Survey (referred to as SAGE Wave 0). Wave 2 data collection will start in 2012/13, following up all Wave 1 respondents. Wave 3 is planned for 2014/15. SAGE is committed to the public release of study instruments, protocols and meta- and micro-data: access is provided upon completion of a Users Agreement available through WHO's SAGE website (www.who.int/healthinfo/systems/sage) and WHO's archive using the National Data Archive application (http://apps.who.int/healthinfo/systems/surveydata).
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| 35. |
- Marcelli, L., et al.
(författare)
-
The Mini-EUSO telescope on board the ISS: in-flight operations and performances
- 2022
-
Ingår i: Proceedings International Conference on Technology and Instrumentation in Particle Physics, TIPP 2021. - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a high sensitivity imaging telescope that observes the Earth from the ISS in the ultraviolet band (2904÷430 nm), through the UV-transparent window in the Russian Zvezda module. The instrument, launched in 2019 as part of the ESA mission Beyond, has a field of view of 44°, a spatial resolution on the Earth surface of 6.3 km and a temporal resolution of 2.5 microseconds. The telescope detects UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few microseconds upwards. Mini-EUSO main detector optics is composed of two Fresnel lenses focusing light onto an array of 36 Hamamatsu multi-anode photomultiplier tubes, for a total of 2304 pixels. The telescope also contains: two ancillary cameras to complement measurements in the near infrared and visible ranges, an array of Silicon-PhotoMultipliers and UV sensors to manage night-day transitions. In this work we will describe the in-flight operations and performances of the various instruments in the first months after launch.
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| 36. |
- Mikkelsen, Tarjei S, et al.
(författare)
-
Genome of the marsupial Monodelphis domestica reveals innovation in non-coding sequences
- 2007
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7141, s. 167-177
-
Tidskriftsartikel (refereegranskat)abstract
- We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.
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| 37. |
- Aladov, V ,A., et al.
(författare)
-
A study of thermal regime in the high-power LED arrays
- 2018
-
Ingår i: St. Petersburg Polytechnical University Journal: Physics and Mathematics. - : Polytechnical Univ Publishing House. - 2405-7223. ; 11:3, s. 39-51
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal resistance and temperature distribution for high-power AlGaInN LED chip-on-board arrays were measured by different methods and tools. The p-n junction temperature was determined through measuring a temperature-dependent forward voltage drop on the p-n junction, at a low measuring current after applying a high heating current. Furthermore, the infrared thermal imaging technique was employed to obtain the temperature map for the test object. A steady-state 3D computational model of the experimental setup was created including temperature-dependent power dissipation in the LED chips. Simulations of the heat transfer in the LED array were performed to further investigate temperature gradients observed in the measurements. Simulations revealed possible thermal deformation of the assembly as the reason for the hot spot formation. The bending of the assembly was confirmed by surface curvature measurements.
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| 38. |
|
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| 39. |
- Balafendie, R., et al.
(författare)
-
Wire metamaterial use for dark matter detection
- 2022
-
Ingår i: 2022 16th International Congress on Artificial Materials for Novel Wave Phenomena, Metamaterials 2022. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 46-48
-
Konferensbidrag (refereegranskat)abstract
- In this work we present our insights into the electromagnetic properties of a resonator recently suggested for the search of axions - a hypothetical candidate to particles of dark matter. A wire medium loaded resonator called a plasma haloscope when used to search for dark matter consists of a metal box filled with a dense array of parallel wires electrically connected to top and bottom walls. We show that the resonator quality Q at the frequency of our interest drops versus the growth of the resonator volume V until it is dominated by resistive losses in the wires. However, we find that in spite of these losses even at room temperature the metal like copper offer the quality factors in the thousands, an order of magnitude higher than the quality originally assumed by the authors of the concept. We have also found a way to tune the resonant frequency so that to better match the phases of the resonator eigenmode to that of the axion. It is achieved by mechanical movement of wires in relation to each other that allows up to 30% change in the resonance frequency. Finally, we discuss how to further improve the wire medium resonators for detection of axions.
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| 40. |
- Belov, A., et al.
(författare)
-
Mini-EUSO photodetector module data processing system
- 2017
-
Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a UV telescope which is developed by the JEM-EUSO collaboration to be placed on board the International Space Station (ISS) to carry out measurements of UV atmosphere airglow and transient luminous events (TLEs) in a wide field of view (>40°) and high temporal resolution (2.5 μs). Mini-EUSO is developed to be a space qualified pathfinder of future JEMEUSO missions. Optical system of the detector consists of two Fresnel lenses of 25 cm diameter. The focal surface is composed of 36 produced by Hamamatsu multi anode photomultiplier tubes (MAPMT), each with 64 pixels. The output signal of all 2304 pixels is digitized and then passed to the data processing system that was specially developed for the experiment and is being discussed in this work. Data processing system is based on produced by Xilinx ZYNQ chip that contains both programmable part (FPGA) and processor. Such combination in a single chip gives a big advantage for processing a data gathered from focal surface including fast multi-level trigger algorithms, data buffering, MAPMTs high voltage control algorithms, interfaces with front-end electronics and with the separate central processor unit for data storage. The multi-level trigger was developed for the mini-EUSO instrument to perform measurements in various time scales (temporal resolutions 2.5 μs, 320 μs, 40 ms). This trigger was successfully implemented and tested.
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| 41. |
- Belov, A., et al.
(författare)
-
The integration and testing of the Mini-EUSO multi-level trigger system
- 2017
-
Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177.
-
Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. The main goal of the mission is to map the Earth in the UV, thus increasing the technological readiness level of future EUSO experiments and to lay the groundwork for the detection of Extreme Energy Cosmic Rays (EECRs) from space (Ebisuzaki et al., 2014). Due to its high time resolution of 2.5 μs, Mini-EUSO is capable of detecting a wide range of UV phenomena in the Earth’s atmosphere. In order to maximise the scientific return of the mission, it is necessary to implement a multi-level trigger logic for data selection over different timescales. This logic is key to the success of the mission and thus must be thoroughly tested and carefully integrated into the data processing system prior to the launch. This article introduces the motivation behind the trigger design and details the integration and testing of the logic.
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| 42. |
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| 43. |
- Belov, M P, et al.
(författare)
-
Ab initio lattice dynamics of CoH and NiH
- 2011
-
Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 509, s. S857-S859
-
Tidskriftsartikel (refereegranskat)abstract
- Ground state parameters and lattice dynamics of CoH and NiH phases are studied by means of the state-of-the-art ab initio pseudopotentials methods. Calculated ground state parameters and phonon DOS are in rather good agreement with available experimental data. No phase transformation for CoH and NiH was found in a wide pressure and temperature range.
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| 44. |
- Belov, M P, et al.
(författare)
-
Hydrogen in the approximant i-TiZrHf: The energy state, charge, and diffusion
- 2010
-
Ingår i: PHYSICS OF THE SOLID STATE. - : Springer Science Business Media. - 1063-7834. ; 52:6, s. 1111-1114
-
Tidskriftsartikel (refereegranskat)abstract
- The energy of hydrogen dissolution in different tetrahedral pores of a 1/1 approximant of the icosahedral TiZrHf quasicrystal has been determined in terms of the density functional theory and ab initio pseudopotentials. At low and high degrees of loading of TiZrHf with hydrogen, the charges of atoms involved in the system and the Mayer bond order have been calculated for all possible M-M and M-H pairs. The diffusion coefficient of a single hydrogen atom in the system under study has been estimated numerically.
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| 45. |
- Belov, M. P., et al.
(författare)
-
Temperature-dependent lattice dynamics of antiferromagnetic and ferromagnetic phases of FeRh
- 2020
-
Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:13
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated lattice dynamics of antiferromagnetic and ferromagnetic phases of cubic (B2) FeRh at various temperatures from first principles using the temperature-dependent effective potential method. We have shown that already at low temperature the cubic structure of the antiferromagnetic phase becomes dynamically stable, which eliminates the contradiction between experimental observations and previous theoretical results showing its dynamical instability at temperature T = 0 K. In addition, we have observed a significant difference in the temperature dependence of lattice vibrations of the ferromagnetic and antiferromagnetic phases. The phonon spectrum of the FM phase softens much stronger than that of the AFM phase, which provides additional contribution to the increase of vibrational entropy of the FM phase at high temperatures. The calculated difference between the vibrational entropies of the FM and AFM phases at a metamagnetic transition temperature (350 K) is 16 J/kg/K. This value is comparable with the experimental value of the total entropy change. We therefore conclude that the lattice dynamics plays a decisive role in the metamagnetic phase transition in FeRh and its remarkable magnetocaloric properties.
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| 46. |
- Belov, Vladimir, et al.
(författare)
-
Multi-site benchmark classification of major depressive disorder using machine learning on cortical and subcortical measures
- 2024
-
Ingår i: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- Machine learning (ML) techniques have gained popularity in the neuroimaging field due to their potential for classifying neuropsychiatric disorders. However, the diagnostic predictive power of the existing algorithms has been limited by small sample sizes, lack of representativeness, data leakage, and/or overfitting. Here, we overcome these limitations with the largest multi-site sample size to date (N = 5365) to provide a generalizable ML classification benchmark of major depressive disorder (MDD) using shallow linear and non-linear models. Leveraging brain measures from standardized ENIGMA analysis pipelines in FreeSurfer, we were able to classify MDD versus healthy controls (HC) with a balanced accuracy of around 62%. But after harmonizing the data, e.g., using ComBat, the balanced accuracy dropped to approximately 52%. Accuracy results close to random chance levels were also observed in stratified groups according to age of onset, antidepressant use, number of episodes and sex. Future studies incorporating higher dimensional brain imaging/phenotype features, and/or using more advanced machine and deep learning methods may yield more encouraging prospects.
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| 47. |
- Capel, Francesca, et al.
(författare)
-
Mini-EUSO : A high resolution detector for the study of terrestrial and cosmic UV emission from the International Space Station
- 2017
-
Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948.
-
Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will map the earth in the UV range (300-400. nm) with a spatial resolution of 6.11. km and a temporal resolution of 2.5. μs, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation. The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration.
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| 48. |
- Dubrovinsky, Leonid, et al.
(författare)
-
Materials synthesis at terapascal static pressures
- 2022
-
Ingår i: Nature. - London, United Kingdom : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 605:7909, s. 274-278
-
Tidskriftsartikel (refereegranskat)abstract
- Theoretical modelling predicts very unusual structures and properties of materials at extreme pressure and temperature conditions(1,2). Hitherto, their synthesis and investigation above 200 gigapascals have been hindered both by the technical complexity of ultrahigh-pressure experiments and by the absence of relevant in situ methods of materials analysis. Here we report on a methodology developed to enable experiments at static compression in the terapascal regime with laser heating. We apply this method to realize pressures of about 600 and 900 gigapascals in a laser-heated double-stage diamond anvil cell(3), producing a rhenium-nitrogen alloy and achieving the synthesis of rhenium nitride Re7N3-which, as our theoretical analysis shows, is only stable under extreme compression. Full chemical and structural characterization of the materials, realized using synchrotron single-crystal X-ray diffraction on microcrystals in situ, demonstrates the capabilities of the methodology to extend high-pressure crystallography to the terapascal regime.
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| 49. |
- Fallqvist, Amie, et al.
(författare)
-
Resolving the debated atomic structure of the metastable cubic SiNx tissue phase in nanocomposites with TiN
- 2018
-
Ingår i: Physical Review Materials. - : American Physical Society. - 2475-9953. ; 2:9
-
Tidskriftsartikel (refereegranskat)abstract
- The TiN/SiNx nanocomposite and nanolaminate systems are the archetype for super if not ultrahard materials. Yet, the nature of the SiNx tissue phase is debated. Here, we show by atomically resolved electron microscopy methods that SiNx is epitaxially stabilized in a NaCl structure on the adjacent TiN(001) surfaces. Additionally, electron energy loss spectroscopy, supported by first-principles density functional theory calculations infer that SiNx hosts Si vacancies.
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| 50. |
- Fausti, F., et al.
(författare)
-
A multi-level triggering system for the Mini-EUSO UV telescope
- 2017
-
Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- As a pathfinder for the JEM-EUSO mission, Mini-EUSO is a 25cm diameter telescope which is going to be launched and positioned inside the International Space Station (ISS) in 2018. The main scientific goal of this mission is the achievement of a state-of-the-art UV map of the Earth from a 400 Km altitude, with ∼ 6 km of pixel spatial resolution, collecting data though a multi-level triggering system. The signal is collected with Multi-Anode Photo Multiplier Tubes (MAPMTs) and digitized by means of custom chips. The raw data moves then to a central system, the Zynq Board, where the trigger operates a data selection dividing different classes of events characterized by specific time scales. The acquired UV map will be used as discrimination threshold for the Extreme Energy Cosmic-Ray detection.
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