918 research outputs found
Feedback-free optical cavity with self-resonating mechanism
We demonstrated the operation of a high finesse optical cavity without
utilizing an active feedback system to stabilize the resonance. The effective
finesse, which is a finesse including the overall system performance, of the
cavity was measured to be , and the laser power stored in
the cavity was kW, which is approximately 187,000 times greater
than the incident power to the cavity. The stored power was stabilized with a
fluctuation of , and we confirmed continuous cavity operation for more
than two hours. This result has the potential to trigger an innovative
evolution for applications that use optical resonant cavities such as compact
photon sources with laser-Compton scattering or cavity enhanced absorption
spectroscopy.Comment: 5 pages, 7 figure
Comparison of lens- and fiber-coupled CCD detectors for X-ray computed tomography
Lens- and fiber-coupled X-ray detectors with identical CCD chips were compared in their performance in high-resolution computed tomography experiments
Development of an intense positron source using a crystal--amorphous hybrid target for linear colliders
In a conventional positron source driven by a few GeV electron beam, a high
amount of heat is loaded into a positron converter target to generate intense
positrons required by linear colliders, and which would eventually damage the
converter target. A hybrid target, composed of a single crystal target as a
radiator of intense gamma--rays, and an amorphous converter target placed
downstream of the crystal, was proposed as a scheme which could overcome the
problem.This paper describes the development of an intense positron source with
the hybrid target. A series of experiments on positron generation with the
hybrid target has been carried out with a 8--GeV electron beam at the KEKB
linac. We observed that positron yield from the hybrid target increased when
the incident electron beam was aligned to the crystal axis and exceeded the one
from the conventional target with the converter target of the same thickness,
when its thickness is less than about 2 radiation length. The measurements in
the temperature rise of the amorphous converter target was successfully carried
out by use of thermocouples. These results lead to establishment to the
evaluation of the hybrid target as an intense positron source.Comment: 17pages, 10figure
Measurement of Dynamic Properties of Pulse Modulated Induction Thermal Plasmas Using Langmuir Probes
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