1,791 research outputs found
Performance of Geant4 in simulating semiconductor particle detector response in the energy range below 1 MeV
Geant4 simulations play a crucial role in the analysis and interpretation of
experiments providing low energy precision tests of the Standard Model. This
paper focuses on the accuracy of the description of the electron processes in
the energy range between 100 and 1000 keV. The effect of the different
simulation parameters and multiple scattering models on the backscattering
coefficients is investigated. Simulations of the response of HPGe and
passivated implanted planar Si detectors to \beta{} particles are compared to
experimental results. An overall good agreement is found between Geant4
simulations and experimental data
The strong and the hungry: Bias in capture methods for mountain hares (Lepus timidus).
Estimating density, age and sex structure of wild populations is a key objective in wildlife management. Live trapping is
frequently used to collect data on populations of small and medium-sized mammals. Ideally, sampling mammal
populations by live capturing of individuals provides a random and representative sample of the target population.
Trapping data may, however, be biased. We used live-capture data from mountain hares Lepus timidus in Scotland to
assess sampling bias between two different capture methods.Wecaptured hares using baited cage traps and long nets on
five study areas in the Scottish Highlands. After controlling for the effects of body size, individuals caught in traps were
lighter than individuals caught using long nets, suggesting that the body condition of hares differed between the capture
methods. This tendency may reflect an increased risk-taking of individuals in poorer body condition and less aversion to
entering traps in order to benefit from eating bait. Overall, we caught more adult hares than juveniles and more female
hares than males. Our results show that estimates of density and population structure of mountain hares using livecapture
data could be affected by the capture method used. We suggest that live-capture studies employ more than one
capture method and test for heterogeneity in capture probability to minimise potential bias and achieve reliable
estimates of population parameters
Habitat effects on hoarding plasticity in the Eurasian red squirrel (Sciurus vulgaris).
Hoarding patterns can be classified into two general types: scatter-hoarding and larder-hoarding, but there are intermediate types. Various factors affect hoarding patterns. Animals hoarding identical seeds in different habitats may use different hoarding patterns to adapt to habitat variation.
We used a sample-plot investigation method to study cache features and recovery rate of seeds of Arolla pine (Pinus cembra) by Eurasian red squirrels (Sciurus vulgaris) in 2009 and 2010 in two subalpine forests with different tree-species composition in the Italian Alps. Hoarding patterns
of red squirrels varied among habitats: the typical scatter-hoarding pattern with most caches including 2-6 seeds is found in spruce (Picea abies) dominated forest, while a combination of few large caches (10 seeds) and many small caches (less than 10 seeds) is found in Arolla pine dominated forest. Consequently, average number of seeds/cache was higher in the latter habitat. Among five microhabitats, shrubs, grass, moss, fallen leaves, and stone, Eurasian red squirrels preferred
fallen leaves and moss as hoarding substrate. Cache recovery investigation indicated that recovery rate was 62% in spruce forest and only 21% in Arolla pine forest. A lower availability of suitable
hoarding microhabitat resulted in changes in hoarding patterns of red squirrels in Pinus cembra dominated forest. We suggest that the main factor influencing differences in recovery rate was a higher cone production per tree in Pinus cembra forest
First detection and energy measurement of recoil ions following beta decay in a Penning trap with the WITCH experiment
The WITCH experiment (Weak Interaction Trap for CHarged particles) will
search for exotic interactions by investigating the beta-neutrino angular
correlation via the measurement of the recoil energy spectrum after beta decay.
As a first step the recoil ions from the beta-minus decay of 124In stored in a
Penning trap have been detected. The evidence for the detection of recoil ions
is shown and the properties of the ion cloud that forms the radioactive source
for the experiment in the Penning trap are presented.Comment: 9 pages, 6 figures (9 figure files), submitted to European Physical
Journal
Monte Carlo simulation of ICRF discharge initiation in ITER
Discharges produced and sustained by ion cyclotron range of frequency (ICRF) waves in absence of plasma current will be used on ITER for (ion cyclotron-) wall conditioning (ICWC). The here presented simulations aim at ensuring that the ITER ICRH& CD system can be safely employed for ICWC and at finding optimal parameters to initiate the plasma.
The 1D Monte Carlo code RFdinity1D3V was developed to simulate ICRF discharge initiation. The code traces the electron motion along one toroidal magnetic field line, accelerated by the RF field in front of the ICRF antenna. Electron collisions in the calculations are handled by a Monte Carlo procedure taking into account their energies and the related electron collision cross sections for collisions with H-2, H-2(+) and H+. The code also includes Coulomb collisions between electrons and ions (e - e; e - H-2(+); e - H+).
We study the electron multiplication rate as a function of the RF discharge parameters (i) antenna input power (0.1-5MW), and (ii) the neutral pressure (H-2) for two antenna phasing (monopole [0000]-phasing and small dipole [0 pi 0 pi]-phasing). Furthermore, we investigate the electron multiplication rate dependency on the distance from the antenna straps. This radial dependency results from the decreasing electric amplitude and field smoothening with increasing distance from the antenna straps.
The numerical plasma breakdown definition used in the code corresponds to the moment when a critical electron density nec for the low hybrid resonance (omega = omega(LHR)) is reached. This numerical definition was previously found in qualitative agreement with experimental breakdown times obtained from the literature and from experiments on the ASDEX Upgrade and TEXTOR
The MuPix Telescope: A Thin, high Rate Tracking Telescope
The MuPix Telescope is a particle tracking telescope, optimized for tracking
low momentum particles and high rates. It is based on the novel High-Voltage
Monolithic Active Pixel Sensors (HV-MAPS), designed for the Mu3e tracking
detector. The telescope represents a first application of the HV-MAPS
technology and also serves as test bed of the Mu3e readout chain. The telescope
consists of up to eight layers of the newest prototypes, the MuPix7 sensors,
which send data self-triggered via fast serial links to FPGAs, where the data
is time-ordered and sent to the PC. A particle hit rate of 1 MHz per layer
could be processed. Online tracking is performed with a subset of the incoming
data. The general concept of the telescope, chip architecture, readout concept
and online reconstruction are described. The performance of the sensor and of
the telescope during test beam measurements are presented.Comment: Proceedings TWEPP 2016, 8 pages, 7 figure
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