7,116 research outputs found
A Tracking Fiber Detector based on Silicon Photomultipliers for the Kaos Spectrometer
A tracking detector based on two meters long scintillating fibers read out by
silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at
the Mainz Microtron MAMI. Results from a prototype setup using 2 mm square
fibers and large area SiPM readout are presented. The detection efficiency of
such a combination was measured to be between 83 and 100% depending on the
threshold on the SiPM amplitude. A Monte Carlo simulation based on a physical
model was employed in order to extract the photon detection efficiency of the
SiPM devices.Comment: Contributed to 2008 IEEE Nuclear Science Symposium, 19-25 October
2008, Dresden, German
Detector developments for the hypernuclear programme at PANDA
The technical design of the PANDA experiment at the future FAIR facility next
to GSI is progressing. At the proposed anti-proton storage ring the
spectroscopy of double Lambda hypernuclei is one of the four main topics which
will be addressed by the Collaboration. The hypernuclear experiments require
(i) a dedicated internal target, (ii) an active secondary target of alternating
silicon and absorber material layers, (iii) high purity germanium (HPGe)
detectors, and (iv) a good particle identification system for low momentum
kaons. All systems need to operate in the presence of a high magnetic field and
a large hadronic background. The status of the detector developments for this
programme is summarized.Comment: Contributed to 2008 IEEE Nuclear Science Symposium, 19-25 October
2008, Dresden, German
The Genesis 12–19 (G1219) Study: A Twin and Sibling Study of Gene–Environment Interplay and Adolescent Development in the UK
The Genesis 12–19 (G1219) Study is an ongoing longitudinal study of a sample of UK twin pairs, non-twin sibling pairs, and their parents. G1219 was initially designed to examine the role of gene–environment interplay in adolescent depression. However, since then data have continued to be collected from both parents and their offspring into young adulthood. This has allowed for longitudinal analyses of depression and has enabled researchers to investigate multiple phenotypes and to ask questions about intermediate mechanisms. The study has primarily focused on emotional development, particularly depression and anxiety, which have been assessed at multiple levels of analysis (symptoms, cognitions, and relevant environmental experiences). G1219 has also included assessment of a broader range of psychological phenotypes ranging from antisocial behaviors and substance use to sleep difficulties, in addition to multiple aspects of the environment. DNA has also been collected. The first wave of data collection began in the year 1999 and the fifth wave of data collection will be complete before the end of 2012. In this article, we describe the sample, data collection, and measures used. We also summarize some of the key findings to date
Development of sports vision public information pamphlets
The purpose of this project was to develop a comprehensive/ understandable pamphlet on Sports Vision targeted to the general public. Adequate information in the area of Sports Vision was not available. The project consists of two parts. An informational pamphlet addressing the pertinent areas of Sports Vision in general and sport specific inserts to accompany the pamphlet. The inserts completed are for baseball/softball and tennis/racquet sports
Characterisation of radiation damage in silicon photomultipliers with a Monte Carlo model
Measured response functions and low photon yield spectra of silicon
photomultipliers (SiPM) were compared to multi-photoelectron pulse-height
distributions generated by a Monte Carlo model. Characteristic parameters for
SiPM were derived. The devices were irradiated with 14 MeV electrons at the
Mainz microtron MAMI. It is shown that the first noticeable damage consists of
an increase in the rate of dark pulses and the loss of uniformity in the pixel
gains. Higher radiation doses reduced also the photon detection efficiency. The
results are especially relevant for applications of SiPM in fibre detectors at
high luminosity experiments.Comment: submitted to Nucl. Instr. and Meth.
Effect of sting size on the wake of a sphere at subcritical Reynolds numbers
Vortex shedding and turbulent motion in the wake of a sphere that is supported using
a streamwise-aligned cylindrical sting are investigated at a subcritical Reynolds number of
Re=3800, using high speed particle image velocimetry. The mechanism by which the presence of a sting of increasing diameter relative to the diameter of the sphere influences the wake, in terms of both the small-scale shear instability and the larger wake instability, is
explored and brie
y compared with the two-dimensional analog of the splitter plate introduced into a cylinder wake. The difficulties associated with obtaining converged statistics,
along with the effect of free stream turbulence and sphere vibrations are detailed. An
understanding of the mechanism by which the blockage, or interference, arising from the
presence of the sting influences cross-wake communication and downstream development
is a necessary precursor to studies of active control of the wake using surface actuation on
a sting-mounted sphere
Interaction of laser generated ultrasonic waves with wedge-shaped samples
Wedge-shaped samples can be used as a model of acoustic interactions with samples ranging from ocean wedges, to angled defects such as rolling contact fatigue, to thickness measurements of samples with non-parallel faces. We present work on laser generated ultrasonic waves on metal samples; one can measure the dominant Rayleigh-wave mode, but longitudinal and shear waves are also generated. We present calculations, models, and measurements giving the dependence of the arrival times and amplitudes of these modes on the wedge apex angle and the separation of generation and detection points, and hence give a measure of the wedge characteristics
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