Search results for "X-ray background"

showing 3 items of 3 documents

17 keV neutrino in a singlet-triplet majoron model

1991

Abstract We investigate the possibility of a cosmologically safe 17 keV neutrino which may have been observed in the decays of tritium, S 35 , and C 14 within a singlet-triplet majoron model. Consideration of the leptonic decay of K + and X rays associated with the radiative decay of massive relic neutrinos severely constrains the scale of the spontaneous lepton number violation. It is argued that the mass density of relic 17 keV neutrinos is constrained as Ω v ⩽ 0.05 h −1 (0.01/ sin 2 θ ) in view of the observed diffuse X ray background.

PhysicsNuclear and High Energy PhysicsParticle physicsPhysics::Instrumentation and DetectorsAstrophysics::High Energy Astrophysical PhenomenaHigh Energy Physics::PhenomenologyDark matterX-ray backgroundAstrophysics::Cosmology and Extragalactic AstrophysicsLepton numberCosmologyNuclear physicsHigh Energy Physics::ExperimentSinglet stateNeutrinoMajoronBosonPhysics Letters B
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CONTRIBUTION OF PSEUDO-FOCUSED SOFT PROTONS TO THE BACKGROUND OF ATHENA

2021

This PhD thesis explores the role of low energy protons, the so-called ‘soft protons', as a component of the background in view of the future ESA's X-ray mission Athena. As a matter of fact, a high level of soft proton flux at the focal plane of Athena can adversely affect the scientific goals of the mission. To prevent this, a correct estimate of the soft proton flux expected at the focal plane of the satellite is fundamental. Such an estimate can be achieved only if the reflectivity of soft protons from the optics is well understood, with efforts on both the experimental and the theoretical sides. To this aim, I applied the model of reflectivity of particles at grazing incidence proposed …

X-ray binariesX-ray binarySettore FIS/05 - Astronomia E AstrofisicaX-ray backgroundX-ray astronomy Inelastic X-ray scattering X-ray optics X-ray pulsar neutron starsoft proton530520
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Preliminary assessment of the ATHENA/WFI non-X-ray background

2017

We present a preliminary assessment of the non-X-ray background for the WFI on board ATHENA conducted at IAAT in the context of the collaborative background and radiation damage working group activities. Our main result is that in the baseline configuration originally assumed for the camera the requirement on the level of non-X-ray background could not be met. In light of the results of Geant4 simulations we propose and discuss a possible optimization of the camera design and pinpoint some open issues to be addressed in the next phase of investigation. One of these concerns the possible contribution to the non-X-ray background from soft protons and ions funneled to the focal plane through t…

Physicsbusiness.industryX-ray backgroundGeant4Astronomy and AstrophysicsContext (language use)ATHENA/WFIAstronomy and Astrophysic01 natural sciences010309 opticsOn boardCardinal pointOpticsSettore FIS/05 - Astronomia E AstrofisicaSpace environmentSpace and Planetary ScienceProton scattering0103 physical sciencesSystems engineeringNon-X-ray backgroundbusiness010303 astronomy & astrophysicsSpace environmentExperimental Astronomy
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