14956820
A pot of gold at the end of the cosmic “raynbow”?
Abstract We critically review the common belief that ultrahigh energy cosmic rays are protons or atomic nuclei with masses not exceeding that of iron. We find that heavier nuclei are indeed possible, and discuss possible sources and acceleration mechanisms for such primaries. We also show detailed simulations of extensive air showers produced by “superheavy” nuclei, and discuss prospects for their detection in future experiments.
119211412
Electron Capture in a Fully Ionized Plasma
Properties of fully ionized water plasmas are discussed including plasma charge density oscillations and the screening of the Coulomb law especially in the dilute classical Debye regime. A kinetic model with two charged particle scattering events determines the transition rate per unit time for electron capture by a nucleus with the resulting nuclear transmutations. Two corrections to the recent Maiani et al. calculations are made: (i) The Debye screening length is only employed within its proper domain of validity. (ii) The WKB approximation employed by Maiani in the long De Broglie wave length limit is evidently invalid. We replace this incorrect approximation with mathematically rigorous Calogero inequalities in order to discuss the scattering wave functions. Having made these corrections, we find a verification for our previous results based on condensed matter electro-weak quantum field theory for nuclear transmutations in chemical batteries.
122164657
Properties of the avalanche photodiodes for the CMS electromagnetic calorimeter
Abstract The electromagnetic calorimeter of the CMS experiment at CERN's Large Hadron Collider will use 122 400 Avalanche Photodiodes from Hamamatsu Photonics. The design of this APD type is the result of a long R & D program performed by Hamamatsu Photonics and the CMS collaboration. The APD parameters including the behavior under irradiation are discussed in view of our application.
122685808
Opacity of the microwave background radiation to ultrahigh energy cosmic rays
In this work we re-examine the influence of the microwave background radiation on the propagation of extremely high energy cosmic rays. We present a recalculation of the rate of fractional energy loss in the continuous energy loss approximation including the effects of resonances other than the Δ. We also discuss the distortion of the cosmic ray spectrum due to interactions with the relic photons.
119407673
Ultrahigh Energy Cosmic Rays: The state of the art before the Auger Observatory
In this review we discuss the important progress made in recent years towards understanding the experimental data on cosmic rays with energies $\agt 10^{19}$ eV. We begin with a brief survey of the available data, including a description of the energy spectrum, mass composition, and arrival directions. At this point we also give a short overview of experimental techniques. After that, we introduce the fundamentals of acceleration and propagation in order to discuss the conjectured nearby cosmic ray sources. We then turn to theoretical notions of physics beyond the Standard Model where we consider both exotic primaries and exotic physical laws. Particular attention is given to the role that TeV-scale gravity could play in addressing the origin of the highest energy cosmic rays. In the final part of the review we discuss the potential of future cosmic ray experiments for the discovery of tiny black holes that should be produced in the Earth's atmosphere if TeV-scale gravity is realized in Nature.
122969664
Radiation damage studies of multipixel geiger-mode avalanche photodiodes
Abstract Results on the radiation hardness of multipixel Geiger-mode avalanche photodiodes (G-APDs) are presented. Recently developed G-APDs from three manufacturers (Hamamatsu (Japan), CPTA(Russia) and Mikron/Dubna(Russia)) were exposed to 28 MeV positrons with fluences up to 8 × 10 10 positrons / cm 2 at the Paul Scherrer Institute. The effects of this radiation on many G-APD parameters such as gain, photon detection efficiency, dark current and count rate for these devices are shown and discussed.
117183644
FEASIBILITY STUDY OF A 15- TO 70-Mev SEPARATED-ORBIT CYCLOTRON AS A BOOSTER INJECTOR
122452337
THE PLUNGING MAGNET SYSTEM FOR THE NIMROD EXTRACTED PROTON BEAM