Limits for an inverse bremsstrahlung origin of the diffuse Galactic soft gamma-ray emission

RXTE, GINGA, and OSSE observations have revealed an intense low-energy gamma-ray continuum emission from the Galactic plane, which is commonly interpreted as evidence for the possible existence of a strong flux of low-energy cosmic ray electrons. In this paper I discuss the scenario of a hadronic origin of the soft Galactic gamma-ray continuum through inverse bremsstrahlung. A flux of low-energy cosmic rays strong enough to produce the observed spectrum of gamma-rays implies substantial gamma-ray emission at a few MeV through nuclear de-excitation. It is shown that the existing limits on excess 3-7 MeV emission from the Galactic plane, in concert with the constraints from pion-decay gamma-ray emission at higher energies, are in serious conflict with an inverse bremsstrahlung origin of the Galactic soft gamma-ray emission for any physically plausible low-energy cosmic ray spectrum. While in case of energetic heavy nuclei the limits are violated by about an order of magnitude, for a large population of low-energy protons the implied gamma-ray line flux and pion-decay continuum intensity are larger than the existing limits by at least a factor of 2.Comment: 4 pages, accepted for publication in A&

AMS tracking in-orbit performance

AMS-02 is a high precision magnetic spectrometer for cosmic rays in the GeV to TeV energy range. Its tracker consists of nine layers of double-sided silicon microstrip sensors. They are used to locate the trajectories of cosmic rays in the 0.14 T field of a cylindrical magnet, thus measuring their rigidity $p/Z$ and charge sign. In addition, they deliver a high resolution measurement of the absolute charge $|Z|$. The detector has been designed to operate in space with a position resolution of about 10 $\mu$m for each hit and charge identification capabilities up to $Z=26$. In this talk I describe the performance in orbit of this detector component and its impact on the overall performance of the spectrometer.Comment: 24th International Workshop on Vertex Detectors, 1-5 June 2015, Santa Fe, New Mexico, US

Experimentation and Physics at a Future Electron-Positron Linear Collider

I summarise the physics opportunities and experimental challenges at future Linear Colliders, using material from the recent ECFA/DESY workshop on the subject as well as contributions to the series of worldwide studies. For reasons of economy, the discussion is restricted to the European Tesla project and to its electron-positron mode only.Comment: 31 pages, 23 figures, 4 tables Invited talk given at the XXVIII International Meeting on Fundamental Physics, Sanl\'ucar de Barrameda, C\'adiz, Spain, 14-18 February 2000 Better figures at http://home.cern.ch/pohl/tesla.htm