113 research outputs found
Spatial methods for event reconstruction in CLEAN
In CLEAN (Cryogenic Low Energy Astrophysics with Noble gases), a proposed
neutrino and dark matter detector, background discrimination is possible if one
can determine the location of an ionizing radiation event with high accuracy.
We simulate ionizing radiation events that produce multiple scintillation
photons within a spherical detection volume filled with liquid neon. We
estimate the radial location of a particular ionizing radiation event based on
the observed count data corresponding to that event. The count data are
collected by detectors mounted at the spherical boundary of the detection
volume. We neglect absorption, but account for Rayleigh scattering. To account
for wavelength-shifting of the scintillation light, we assume that photons are
absorbed and re-emitted at the detectors. Here, we develop spatial Maximum
Likelihood methods for event reconstruction, and study their performance in
computer simulation experiments. We also study a method based on the centroid
of the observed count data. We calibrate our estimates based on training data
Demonstration of photomultiplier tube operation at 29 K
We describe measurements of gain, dark current, and quantum efficiency
obtained while cooling a Hamamatsu R5912-02-MOD photomultiplier tube from room
temperature to 29 K. We found that the PMT operated normally down to 29 K, with
a reduced gain and quantum efficiency at the lowest temperatures. Furthermore,
we found that the dark count rate increased as the temperature decreased. We
conclude that these PMTs appear to be adequate for the requirements of the
CLEAN experiment.Comment: 3 pages, 5 figure
Dark Matter in the Coming Decade: Complementary Paths to Discovery and Beyond
In this report we summarize the many dark matter searches currently being
pursued through four complementary approaches: direct detection, indirect
detection, collider experiments, and astrophysical probes. The essential
features of broad classes of experiments are described, each with their own
strengths and weaknesses. The complementarity of the different dark matter
searches is discussed qualitatively and illustrated quantitatively in two
simple theoretical frameworks. Our primary conclusion is that the diversity of
possible dark matter candidates requires a balanced program drawing from all
four approaches.Comment: Report prepared for the Community Summer Study (Snowmass) 2013, on
behalf of Cosmic Frontier Working Groups 1-4 (CF1: WIMP Dark Matter Direct
Detection, CF2: WIMP Dark Matter Indirect Detection, CF3: Non-WIMP Dark
Matter, and CF4: Dark Matter Complementarity); published versio
Measurement of scintillation efficiency for nuclear recoils in liquid argon
The scintillation light yield of liquid argon from nuclear recoils relative to electronic recoils has been measured as a function of recoil energy from 10 keVr up to 250 keVr at zero electric field. The scintillation efficiency, defined as the ratio of the nuclear recoil scintillation response to the electronic recoil response, is 0.25±0.01+0.01 (correlated) above 20 keVr. © 2012 American Physical Society
Estimating the effects of the container revolution on world trade
Many historical accounts have asserted that containerization triggered complementary technological and organizational changes that revolutionized global freight transport. We are the first to suggest an identification strategy for estimating the effects of the container revolution on world trade. Our empirical strategy exploits time and cross-sectional variation in countries’ first adoption of container facilities and combines it with product-level variation in containerizability and container usage. Applying our container variables on a large panel of product level trade flows for the period 1962-1990, our estimates suggest economically large concurrent and cumulative effects of containerization and lend support for the view of containerization being a driver of 20th century economic globalization
Dark sectors 2016 Workshop: community report
This report, based on the Dark Sectors workshop at SLAC in April 2016,
summarizes the scientific importance of searches for dark sector dark matter
and forces at masses beneath the weak-scale, the status of this broad
international field, the important milestones motivating future exploration,
and promising experimental opportunities to reach these milestones over the
next 5-10 years
US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report
This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in
Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference
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