204 research outputs found
Hybrid ECAL: Optimization and Related Developments
Hybrid ECAL is a cost-conscious option of electromagnetic calorimeter (ECAL)
for particle flow calorimetry to be used in a detector of International Linear
Collider (ILC). It is a combination of silicon-tungsten ECAL, which realizes
high granularity and robust measurement of electromagnetic shower, and
scintillator-tungsten ECAL, which gives affordable cost with similar
performance to silicon. Optimization and a data acquisition trial in a test
bench for the hybrid ECAL are described in this article.Comment: 7 pages, 4 figures, Talk presented at the International Workshop on
Future Linear Colliders (LCWS14), Belgrade, Serbia, 6-10 October 201
Precise measurement of HFS of positronium
The ground state hyperfine splitting in positronium, , is sensitive to high order corrections of QED. A new
calculation up to has revealed a discrepancy
between the QED prediction and the experimental results. This discrepancy might
either be due to systematic problems in the previous experiments or to
contributions beyond the Standard Model. We propose an experiment to measure
employing new methods designed to remedy the systematic
errors which may have affected the previous experiments. Our experiment will
provide an independent check of the discrepancy. The measurement is in progress
and a preliminary result of has been obtained. A measurement with a
precision of O(1) ppm is expected within a few years.Comment: 5 pages, 6 figures, contributed to POSMOL 2009, will be published in
J. Phys.: Conf. Serie
Study of silicon sensors for precise timing measurement
Silicon sensors with high time resolution can help particle identification in
the International Linear Collider (ILC). We are studying Low Gain Avalanche
Diodes (LGADs) as a high timing resolution sensor. As a step to develop LGADs,
we are now focusing to characterize Avalanche Photo Diode (APD)s, because the
APDs has the same multiplication structure as LGADs. We studied the
characteristics of APDs with particles from radioisotopes
Measurement of Positronium hyperfine splitting with quantum oscillation
Interference between different energy eigenstates in a quantum system results
in an oscillation with a frequency which is proportional to the difference in
energy between the states. Such an oscillation is observable in polarized
positronium when it is placed in a magnetic field. In order to measure the
hyperfine splitting of positronium, we perform the precise measurement of this
oscillation using a high quality superconducting magnet and fast
photon-detectors. A result of ~GHz is obtained which is consistent with both theoretical
calculations and previous precise measurements.Comment: 4 figures accepted by Phys. Lett.
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