54800032
Development of a three dimensional four mirror optical cavity for laser-Compton scattering
Abstract This paper describes a design and performance of a three-dimensional 4-mirror optical cavity for development of intense photon sources by laser-Compton scattering. We achieved the finesse of 4000 and average power of 2.6 kW in the cavity with the vertical laser beam spot size of 13 ± 1 μ m in σ at the laser–electron interaction point. As a result, we observed 124±1 photons with average energy of 24 MeV per beam crossing, which corresponds to the generation of 2.7×10 8 photons per second.
67793170
GAMMA-RAYS GENERATION WITH 3D 4-MIRROR CAVITY FOR ILC POLARIZED POSITRON SOURCE
We are developing a ILC polarized positron source based on the laser-Compton scattering. We have already performed a photon generation experiment at the KEK-ATF using a Fabry-Perot type 2-mirror laser pulse stacking cavity [1]. The laser pulses are accumulated and their power was enhanced in the Fabry-Perot cavity. In order further improve performance of the laser power enhancement, a new three dimensional 4-mirror cavity is designed. In this article, we report status of the photon generation experiment.
203217954
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.
120531581
A high resolution holographic freon bubble chamber for the Fermilab high energy neutrino experiment
Abstract A high resolution holographic freon bubble chamber has been constructed for a high energy neutrino experiment at Fermilab. The chamber has a volume of 1150 l filled with a heavy liquid (freon) and has high resolution holographic optics. A muon detector system has been installed to measure high energy muons scattered from the neutrino interactions. Some systematic studies have been done to optimize bubble chamber operation with holographic photography. Results of these studies are presented along with a description of the hybrid bubble chamber system.
14721989
Beam Test Of The SDC Double-sided Silicon Strip Detector
A beam test was executed to evaluate the behavior of the first prototype radiation-hard double-sided silicon microstrip sensor for the SDC silicon tracking system. Pions of 4 GeV/c in a test bcamline at KEK illuminated three planes of detectors. Thc signals wcrc amplified, shaped, and discriminated with TEKZ bipolar analog LSI's, and the on-off levels were sampled at l0MHz clock with CMOS digiwl LSI's, asynchronously with beam triggers. The detectors were rotated in null and 1 .O Tesla magnetic fields. The efficiencies were found to be 98-9996. The position resolutions were 12.5pm. where the multi-strip hit fraction was 30-40%. There was no essential difference in the performance of the pand the n-sides. The multi-strip hit fraction showed a clear rotation and magnetic-field dependence. From the angles where the fractions were minimum in the 1T magnetic field, the Hall mobilities of the electrons and holes were obtained to be 1391k43 (clcctrons) and 325f30 (holes) cm2/Vs.
126251426
Experimental study of the rare decays K0(L) ---> mu e, K0(L) ---> e e, and K0(L) ---> mu mu and K0(L) ---> e e e e