21013020
Conduction Cooling Test of a Splittable Quadrupole for ILC Cryomodules
A superconducting splittable quadrupole magnet was designed at Fermilab for use in ILC-style cryomodules, in which the magnet is to be assembled around the beam tube to avoid contaminating the ultraclean superconducting RF beam volume. This quadrupole was built and first tested in a liquid helium bath environment at Fermilab, where its quench and magnetic performance were characterized. The device is intended to be cooled by conduction when installed in cryomodules, so a separate test was made at KEK where an appropriate conduction cooling test facility exists. We present results of the thermal performance of the magnet in the conduction cooling mode, and discuss its excitation characteristics in this operating mode.
113855195
Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK.
We had been constructing a new facility for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we have installed a deepdrawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the studies on the fabrication of 9-cell cavity for International Linear Collier (ILC) using this facility. The studies are focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We already finished the fabrication of two 9-cell cavities in this facility. This article reports the current status of the studies.
119264611
Relevant gluonic energy scale of spontaneous chiral symmetry breaking from lattice QCD
We analyze which momentum component of the gluon field induces spontaneous chiral symmetry breaking in lattice QCD. After removing the high-momentum or low-momentum component of the gluon field, we calculate the chiral condensate and observe the roles of these momentum components. The chiral condensate is found to be drastically reduced by removing the zero-momentum gluon. The reduction is about 40% of the total in our calculation condition. The nonzero-momentum infrared gluon also has a sizable contribution to the chiral condensate. From the Banks-Casher relation, this result reflects the nontrivial relation between the infrared gluon and the zero-mode quark.
27061707
Lattice QCD in rotating frames.
We formulate lattice QCD in rotating frames to study the physics of QCD matter under rotation. We construct the lattice QCD action with the rotational metric and apply it to the Monte Carlo simulation. As the first application, we calculate the angular momenta of gluons and quarks in the rotating QCD vacuum. This new framework is useful to analyze various rotation-related phenomena in QCD.