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The concept of a small-scale, pulsed-proton accelerator based compact ultracold neutron (UCN) source is presented. The essential idea of the compact UCN source is to enclose a volume of superfluid $^{4}\mathrm{He}$ converter with a…

Instrumentation and Detectors · Physics 2021-03-17 Yun Chang Shin , W. Michael Snow , David V. Baxter , Chen-Yu Liu , Dongok Kim , Younggeun Kim , Yannis K. Semertzidis

Proposals exist and efforts are under way to construct pulsed spallation ultra-cold neutron (UCN) sources at accelerator laboratories around the world. At the Paul Scherrer Institut (PSI), Switzerland, and at the Los Alamos National…

Nuclear Experiment · Physics 2007-05-23 Klaus Kirch

Having previously argued that binary neutron star mergers are the principle source of ultrahigh energy cosmic rays~\citep{fBNS-prl25}, we exploit here the highly constrained initial conditions to make quantitative predictions for the cutoff…

High Energy Astrophysical Phenomena · Physics 2025-11-04 Glennys R. Farrar

Recently Umemura, Fukue, & Mineshige (1997) proposed the radiative avalanche fueling to active galactic nuclei; gas accretion is driven by radiation drag exerted by stellar radiation from circumnuclear starburst regions. This mechanism is…

Astrophysics · Physics 2016-08-30 Yoshiaki Taniguchi

The secondary/primary cosmic-ray ratios and the diffuse backgrounds of gamma rays and neutrinos provide us with complementary information about the transport of Galactic cosmic rays~(CRs). We used the recent measurement of the diffuse gamma…

High Energy Astrophysical Phenomena · Physics 2025-06-13 Antonio Ambrosone , Carmelo Evoli , Benedikt Schroer , Pasquale Blasi

The paper reports on a new plasma startup scenario in the Gas Dynamic Trap (GDT) magnetic mirror device. The primary 5 MW neutral beam injection (NBI) plasma heating system fires into a sufficiently dense plasma target ("seed plasma"),…

The IceCube Neutrino Observatory includes a tightly spaced inner array in the deepest ice, called DeepCore, which gives access to low-energy neutrinos with a sizable surrounding cosmic ray muon veto. Designed to be sensitive to neutrinos at…

High Energy Physics - Experiment · Physics 2019-08-13 Chang Hyon Ha

The multipurpose nature of nuclear research reactors has been investigated. This class of reactors has gained momentum within the international community, given the multiple benefits of nuclear technology in medicine, agriculture, industry,…

Traditional neutrino detectors are built deep underground to reduce backgrounds. The neutrino solar orbiting laboratory ($\nu$SOL) collaboration has been developing a concept to improve neutrino measurement not with a larger detector…

Solar and Stellar Astrophysics · Physics 2025-02-07 Jonathan Folkerts

Estimated masses of fissioning and non-fissioning radioactive elements and their respective distributions within the Earth are presented, based upon the fundamental identity of the components of the interior 82% of the Earth, the…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Marvin Herndon , Dennis A. Edgerley

By means of three-dimensional hydrodynamic simulations with a Eulerian PPM code we investigate the formation and the properties of the accretion torus around the stellar mass black hole which originates from the merging of two neutron…

Astrophysics · Physics 2008-11-26 M. Ruffert , H. -Th. Janka

\abridged The nuclei of active galaxies harbor massive young stars, an accreting central black hole, or both. In order to determine the physical conditions that pertain to molecular gas close to the sources of radiation, numerical models…

Astrophysics · Physics 2009-11-11 R. Meijerink , M. Spaans , F. P. Israel

The gamma-ray burst (GRB) model for production of ultra-high-energy cosmic-rays (UHECRs) is based on the hypothesis that GRBs arise from the dissipation of the kinetic energy of relativistic fireballs at cosmological distances. Recent GRB…

Astrophysics · Physics 2009-10-31 E. Waxman

We present models the gas physics and dynamics of the inner 50 pc of the Galaxy. In a first step the gas properties of an isolated clumpy circumnuclear disk were analytically investigated. We took the external UV radiation field, the…

Astrophysics · Physics 2009-11-07 B. Vollmer , W. J. Duschl , R. Zylka

We aim to explain in a unified way the experimental data on ultrahigh energy cosmic rays (UHECR) and neutrinos, using a single source class and obeying limits on the extragalactic diffuse gamma-ray background (EGRB). If UHECRs only interact…

High Energy Astrophysical Phenomena · Physics 2017-10-11 M. Kachelriess , O. Kalashev , S. Ostapchenko , D. V. Semikoz

Context: As more and more data are collected by cosmic ray experiments such as the Pierre Auger Observatory and Telescope Array (TA), the search for the sources of the Ultra High Energy Cosmic Rays (UHECR) continues. Already we have some…

High Energy Astrophysical Phenomena · Physics 2011-12-06 Laurentiu I. Caramete , Oana Tascau , Peter L. Biermann , Todor Stanev

We discuss processes in galactic cosmic ray (GCR) acceleration sites - supernova remnants, compact associations of young massive stars, and superbubbles. Mechanisms of efficient conversion of the mechanical power of the outflows driven by…

High Energy Astrophysical Phenomena · Physics 2012-12-11 A. M. Bykov , D. C. Ellison , P. E. Gladilin , S. M. Osipov

We calculate the structure and short-term evolution of a gamma ray burst central engine in the form of a turbulent torus accreting onto a stellar mass black hole. Our models apply to the short gamma ray burst events, in which a remnant…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Agnieszka Janiuk , Patryk Mioduszewski , Monika Moscibrodzka

Very-high-energy gamma-ray observations of the Galactic center (GC) show extended emission that is strongly correlated with the morphology of the central molecular zone (CMZ). The best explanation for that emission is a hadronic interaction…

High Energy Astrophysical Phenomena · Physics 2023-11-29 Andrés Scherer , Jorge Cuadra , Franz E. Bauer

There is growing observational evidence that gamma-ray bursts (GRBs) are powered by black holes accreting rapidly through a disk. The supernova-like outburst that accompanies some gamma-ray bursts suggest that some long-duration GRBs may be…

Astrophysics · Physics 2009-10-31 Weiqun Zhang , Chris L. Fryer