1,855 research outputs found
Axes determination for segmented true-coaxial HPGe detectors
A fast method to determine the crystallographic axes of segmented
true-coaxial high-purity germanium detectors is presented. It is based on the
analysis of segment-occupancy patterns obtained by irradiation with radioactive
sources. The measured patterns are compared to predictions for different axes
orientations. The predictions require a simulation of the trajectories of the
charge carriers taking the transverse anisotropy of their drift into account.Comment: 18 pages, 1 table, 31 figures; included background contribution to
the occupancy patterns and systematic uncertainties, results slightly change
Identification of photons in double beta-decay experiments using segmented germanium detectors - studies with a GERDA Phase II prototype detector
The sensitivity of experiments searching for neutrinoless double beta-decay
of germanium was so far limited by the background induced by external
gamma-radiation. Segmented germanium detectors can be used to identify photons
and thus reduce this background component.
The GERmanium Detector Array, GERDA, will use highly segmented germanium
detectors in its second phase. The identification of photonic events is
investigated using a prototype detector. The results are compared with Monte
Carlo data.Comment: 20 pages, 7 figures, to be submitted to NIM-
Pulse shape simulation for segmented true-coaxial HPGe detectors
A new package to simulate the formation of electrical pulses in segmented
true-coaxial high purity germanium detectors is presented. The computation of
the electric field and weighting potentials inside the detector as well as of
the trajectories of the charge carriers is described. In addition, the
treatment of bandwidth limitations and noise are discussed. Comparison of
simulated to measured pulses, obtained from an 18-fold segmented detector
operated inside a cryogenic test facility, are presented.Comment: 20 pages, 16 figure
Abundance analysis of Am binaries and search for tidally driven abundance anomalies - III. HD116657, HD138213, HD155375, HD159560, HD196544 and HD204188
We continue here the systematic abundance analysis of a sample of Am binaries
in order to search for possible abundance anomalies driven by tidal interaction
in these binary systems. New CCD observations in two spectral regions
(6400-6500, 6660-6760 AA) of HD116657, HD138213, HD155375, HD159560, HD196544
and HD204188 were obtained. Synthetic spectrum analysis was carried out and
basic stellar properties, effective temperatures, gravities, projected
rotational velocities, masses, ages and abundances of several elements were
determined. We conclude that all six stars are Am stars. These stars were put
into the context of other Am binaries with 10 < Porb < 200 days and their
abundance anomalies discussed in the context of possible tidal effects. There
is clear anti-correlation of the Am peculiarities with v sin i. However, there
seems to be also a correlation with the eccentricity and may be with the
orbital period. The dependence on the temperature, age, mass, and
microturbulence was studied as well. The projected rotational velocities
obtained by us were compared to those of Royer et al. (2002) and Abt & Morrell
(1995).Comment: 11 pages, 3 tables, 12 figures. Accepted for publication in Monthly
Notices of the Royal Astronomical Societ
Investigation into the limits of perturbation theory at low Q^2 using HERA deep inelastic scattering data
A phenomenological study of the final combined HERA data on inclusive deep
inelastic scattering (DIS) has been performed. The data are presented and
investigated for a kinematic range extending from values of the four-momentum
transfer, , above 10 GeV down to the lowest values observable at
HERA of = 0.045 GeV and Bjorken , = 6
10. The data are well described by fits based on perturbative quantum
chromodynamics (QCD) using collinear factorisation and evolution of the parton
densities encompassed in the DGLAP formalism from the highest down to
of a few GeV. The Regge formalism can describe the data up to 0.65 GeV. The complete data set can be described by a new fit
using the ALLM parameterisation. The region between the Regge and the
perturbative QCD regimes is of particular interest.Comment: 38 pages, 13 figure
Characterization of the first true coaxial 18-fold segmented n-type prototype detector for the GERDA project
The first true coaxial 18-fold segmented n-type HPGe prototype detector
produced by Canberra-France for the GERDA neutrinoless double beta-decay
project was tested both at Canberra-France and at the Max-Planck-Institut fuer
Physik in Munich. The main characteristics of the detector are given and
measurements concerning detector properties are described. A novel method to
establish contacts between the crystal and a Kapton cable is presented.Comment: 21 pages, 16 Figures, to be submitted to NIM
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