We analyze the temporal variation of the diurnal anisotropy of sub-TeV cosmic ray intensity observed with the Matsushiro (Japan) underground muon detector over two full solar activity cycles in 1985-2008. We find an anisotropy component in the solar diurnal anisotropy superimposed on the Compton-Getting anisotropy due to the earth's orbital motion around the sun. The phase of this additional anisotropy is almost constant at ∼15:00 local solar time corresponding to the direction perpendicular to the average interplanetary magnetic field at the earth's orbit, while the amplitude varies between a maximum (0.043±0.002 %) and minimum (∼0.008±0.002 %) in a clear correlation with the solar activity. We find a significant time lag between the temporal variations of the amplitude and the sunspot number and obtain the best correlation coefficient of +0.74 with the sunspot number delayed for 26 months. We suggest that this anisotropy might be interpreted in terms of the energy change due to the solar-wind induced electric field expected for GCRs crossing the wavy neutral sheet. The average amplitude of the sidereal diurnal variation over the entire period is 0.034±0.003 %, which is roughly one third of the amplitude reported from AS and deep-underground muon experiments monitoring multi-TeV GCR intensity suggesting a significant attenuation of the anisotropy due to the solar modulation. We find, on the other hand, only a weak positive correlation between the sidereal diurnal anisotropy and the solar activity cycle, in which the amplitude in the "active" solar activity epoch is about twice the amplitude in the "quiet" solar activity epoch.This implies that only one fourth of the total attenuation varies in correlation with the solar activity cycle and/or the solar magnetic cycle. We finally examine the temporal variation of the "single-band valley depth" (SBVD) quoted by the Milagro experiment and, by contrast with recent Milagro's report, we find no steady increase in the Matsushiro observations in a 7-year period between 2000 and 2007. We suggest, therefore, that the steady increase of the SBVD reported by the Milagro experiment is not caused by the decreasing solar modulation in the declining phase of the 23rd solar activity cycle.Subject headings: diurnal anisotropy of sub-TeV cosmic ray intensity -solar modulation of the sidereal anisotropy -cosmic ray observation with underground muon detector
(Presented on ; published online )A hybrid thin-film coplanar-line with a slit-patterned CoFeB magnetic film for a RF impedance matching was fabricated, and an effect of the loss reduction by introducing a slit-patterned magnetic film was investigated. The fabricated hybrid thin-film coplanar-line device consisted of the top and bottom 5 µm thick copper conductors, an inner (0.5 µm thick polyimide)/(0.15 µm thick CoFeB)/(0.5 µm thick polyimide) trilayer. A signal line width was 6 µm. Total width of the slit-patterned magnetic film was about 200 µm. The devices with some kinds of the width of the magnetic film stripe were fabricated. As a result, insertion loss per unit line length decreased greatly above 1.5 GHz with decreasing width of the magnetic film. The loss suppression was due to an effect of reducing the in-plane eddy current of the magnetic film. On the other hand, the propagation signal-wavelength of the device increased with decreasing width of the magnetic film, which was due to a decrease of distributed inductance. When applying the device to a quarter-wavelength impedance matching device, the slit-patterned magnetic film was effective for decreasing the insertion loss at high frequencies beyond 1.8 GHz.
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