1,627 research outputs found
Extra-large crystal emulsion detectors for future large-scale experiments
Photographic emulsion is a particle tracking device which features the best
spatial resolution among particle detectors. For certain applications, for
example muon radiography, large-scale detectors are required. Therefore, a huge
surface has to be analyzed by means of automated optical microscopes. An
improvement of the readout speed is then a crucial point to make these
applications possible and the availability of a new type of photographic
emulsions featuring crystals of larger size is a way to pursue this program.
This would allow a lower magnification for the microscopes, a consequent larger
field of view resulting in a faster data analysis. In this framework, we
developed new kinds of emulsion detectors with a crystal size of 600-1000 nm,
namely 3-5 times larger than conventional ones, allowing a 25 times faster data
readout. The new photographic emulsions have shown a sufficient sensitivity and
a good signal to noise ratio. The proposed development opens the way to future
large-scale applications of the technology, e.g. 3D imaging of glacier bedrocks
or future neutrino experiments.Comment: Version accepted for publication in JINS
A new application of emulsions to measure the gravitational force on antihydrogen
We propose to build and operate a detector based on the emulsion film
technology for the measurement of the gravitational acceleration on antimatter,
to be performed by the AEgIS experiment (AD6) at CERN. The goal of AEgIS is to
test the weak equivalence principle with a precision of 1% on the gravitational
acceleration g by measuring the vertical position of the anni- hilation vertex
of antihydrogen atoms after their free fall in a horizontal vacuum pipe. With
the emulsion technology developed at the University of Bern we propose to
improve the performance of AEgIS by exploiting the superior position resolution
of emulsion films over other particle de- tectors. The idea is to use a new
type of emulsion films, especially developed for applications in vacuum, to
yield a spatial resolution of the order of one micron in the measurement of the
sag of the antihydrogen atoms in the gravitational field. This is an order of
magnitude better than what was planned in the original AEgIS proposal.Comment: 17 pages, 14 figure
Ретроспективный анализ врождённых пороков развития у плодов и новорожденных в Гродненском областном перинатальном центре за период 2003-2007 год
НОВОРОЖДЕННЫЙ, БОЛЕЗНИПЛОДА ДИСТРЕС
Automatic track recognition for large-angle minimum ionizing particles in nuclear emulsions
We previously developed an automatic track scanning system which enables the
detection of large-angle nuclear fragments in the nuclear emulsion films of the
OPERA experiment. As a next step, we have investigated this system's track
recognition capability for large-angle minimum ionizing particles . This paper shows that, for such tracks, the system has
a detection efficiency of 95 or higher and reports the achieved angular
accuracy of the automatically recognized tracks. This technology is of general
purpose and will likely contribute not only to various analyses in the OPERA
experiment, but also to future experiments, e.g. on low-energy neutrino and
hadron interactions, or to future research on cosmic rays using nuclear
emulsions carried by balloons.Comment: 11 pages, 10 figures, accepted by JINS
Measurement of the muon beam direction and muon flux for the T2K neutrino experiment
The Tokai-to-Kamioka (T2K) neutrino experiment measures neutrino oscillations
by using an almost pure muon neutrino beam produced at the J-PARC accelerator
facility. The T2K muon monitor was installed to measure the direction and
stability of the muon beam which is produced together with the muon neutrino
beam. The systematic error in the muon beam direction measurement was
estimated, using data and MC simulation, to be 0.28 mrad. During beam
operation, the proton beam has been controlled using measurements from the muon
monitor and the direction of the neutrino beam has been tuned to within 0.3
mrad with respect to the designed beam-axis. In order to understand the muon
beam properties,measurement of the absolute muon yield at the muon monitor was
conducted with an emulsion detector. The number of muon tracks was measured to
be cm normalized with protons
on target with 250 kA horn operation. The result is in agreement with the
prediction which is corrected based on hadron production data
Bedrock sculpting under an active alpine glacier revealed from cosmic-ray muon radiography.
Mountain glaciers form landscapes with U-shaped valleys, roche moutonées and overdeepenings through bedrock erosion. However, little evidence for active glacial carving has been provided particularly for areas above the Equilibrium Line Altitude (ELA) where glaciers originate. This is mainly due to our lack of information about the shape of the bedrock underneath active glaciers in highly elevated areas. In the past years, the bedrock morphology underneath active glaciers has been studied by geophysical methods in order to infer the subglacial mechanisms of bedrock erosion. However, these comprise surveys on the glaciers' surface, from where it has been difficult to investigate the lateral boundary between the ice and the bedrock with sufficient resolution. Here we perform a muon-radiographic inspection of the Eiger glacier (Switzerland, European Alps) with the aid of cosmic-ray muon attenuation. We find a reach (600 × 300 m) within the accumulation area where strong lateral glacial erosion has cut nearly vertically into the underlying bedrock. This suggests that the Eiger glacier has profoundly sculpted its bedrock in its accumulation area. This also reveals that the cosmic-ray muon radiography is an ideal technology to reconstruct the shape of the bedrock underneath an active glacier
Chemical constituents and bioactivity of piper sarmentosum: A mini review
Herbs with medicinal potential are important for health and wellness. The main aim of this review article was to disseminate important information regarding the use of Piper sarmentosum as natural medicine. P. sarmentosum have been reported to possess a varying degree of hypoglycemic, antidiabetic and other additional properties. The antioxidant properties of the herbs may be effective in controlling the oxidative damage. The review article highlights the positive role of traditional herbs as alternative medicine
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