122318830
Cryomodule tests of four Tesla-like cavities in the Superconducting RF Test Facility at KEK
A 6-m cryomodule including four Tesla-like cavities was developed, and was tested in the Superconducting RF Test Facility phase-I at KEK. The performance as a total superconducting cavity system was checked in the cryomodule tests at 2 K with high rf power. One of the four cavities achieved a stable pulsed operation at $32\text{ }\text{ }\mathrm{MV}/\mathrm{m}$, which is higher than the operating accelerating gradient in the ILC. The maximum accelerating gradient (${E}_{\mathrm{acc},\mathrm{max}﻿}$) obtained in the vertical cw tests was maintained or slightly improved in the cryomodule tests operating in a pulse mode. Compensation of the Lorentz force detuning at $31\text{ }\text{ }\mathrm{MV}/\mathrm{m}$ was successfully demonstrated by a piezo tuner and predetuning.
67849446
PREPARATION STATUS OF CRYOMODULE TESTS OF TESLA-LIKE CAVITIES IN S1-GLOBAL PROJECT AT KEK
S1-Global project for ILC is an international collaboration for cryomodule tests including eight 9-cell sc cavities from DESY, FNAL and KEK. One of two 6-m cryomodules, Cryomodule-A, contains four Tesla-like cavities with slide-jack tuners and STF-II couplers. The cryomodule was assembled and was installed in the STF tunnel for cool-down tests and high power rf tests. The current preparation status is reported.
113679678
PRESENT STATUS OF SUPERCONDUCTING CAVITY SYSTEM FOR CERL INJECTOR LINAC AT KEK
Construction of the compact ERL (cERL) [1] is underway and fabrication of a SC Cavity Injector Cryomodule has been started last year at KEK. Status of R&D and design details are reported.
118396635
Slow-roll Inflation with the Gauss-Bonnet and Chern-Simons Corrections
We study slow-roll inflation with the Gauss-Bonnet and Chern-Simons corrections. We obtain general formulas for the observables: spectral indices, tensor-to-scalar ratio and circular polarization of gravitational waves. The Gauss-Bonnet term violates the consistency relation r = −8nT. Particularly, blue spectrum nT > 0 and scale invariant spectrum |8nT|/r << 1 of tensor modes are possible. These cases require the Gauss-Bonnet coupling function of ξ, ~ 108/MPl. We use examples to show new-inflation-type potential with 10MPl symmetry breaking scale and potential with flat region in 10MPl lead to observationally consistent blue and scale invariant spectra, respectively. Hence, these interesting cases can actually be realized. The Chern-Simons term produce circularly polarized tensor modes. We show an observation of these signals supports existence of the Chern-Simons coupling function of ω, ~ 108/MPl. Thus, with future observations, we can fix or constrain the value of these coupling functions, at the CMB scale.