KEK, Ibaraki
SLAC, Menlo Park, California
Fermilab, Batavia
INFN/LASA, Segrate (MI)
DESY, Hamburg
In an attempt at demonstrating an average field gradient of 31.5 MV/m as per the design accelerating gradient for ILC, a program called S1-Global is in progress as an international research collaboration among KEK, INFN, FNAL, DESY and SLAC. The design of the S1-G cryomodule began at May 2008 by INFN and KEK. The S1-Global cryomodule was designed to contain eight superconducting cavities from FNAL, DESY and KEK, and to be constructed by joining two half-size cryomodules, each 6 m in length. The module containing four cavities from FNAL and DESY was constructed by INFN. Four KEK cavities have been assembled in the 6 m module which KEK fabricated. All major components were transported to KEK from INFN, FNAL and DESY in December 2009. The assembly of the two 6-m cryomodules started from January 2010 in a collaborative work of FNAL, DESY, INFN and KEK. The construction of the S1-G cryomodule will complete in May, and the cool-down of the S1-G cryomodule is scheduled from June 2010 at the KEK-STF. In this paper, the construction and the cold tests of the S1-Global cryomodule in the worldwide research collaboration will be presented.
Fermilab, Batavia
Project X is a proposed high-intensity proton accelerator complex that could provide beam to create a high-intensity neutrino beam, feed protons to kaon- and muon-based precision experiments, and for other applications still under investigation. The present configuration of the proton accelerator foresees a section with 650 MHz beta = 0.6 and beta = 0.9 elliptical cavities. Prototypes of single-cell 650 MHz cavities and five-cell beta = 0.9 650 MHz cavities are being designed and fabricated at Fermilab in the R&D process for Project X. This paper summarizes the design status of the beta = 0.6 and beta = 0.9 single-cell prototype cavities, and also addresses the design effort focused on the five-cell beta = 0.9 cavities.
Fermilab, Batavia
Fermilab is currently focusing its efforts toward the development of Stainless Steel (SS) helium vessels for its 1.3 GHz SRF cavities. The objective is to transition towards the concept of using SS helium vessels to dress the bare SRF cavities, thereby paving way for significant cost reduction and efficient production techniques for future accelerators. The biggest challenge has been to design a reliable interface between the niobium cavity end group and the stainless steel end flange that encloses the helium vessel. Fermilab has been pursuing a brazed joint design to allow this transition. Additional design challenges associated with this transition are ensuring proper cooling of the cavity, compensating for the difference in thermal contraction between the SS helium vessel and niobium cavities, and also modification of the tuning procedure and ensuring the safety and reliability of the blade and piezo tuners. Current efforts on the qualification of the niobium-SS braze joint, finite element simulations of the thermal design aspects, bench testing of actual cavity displacements, and study of the effects on the tuners will be presented.
Fermilab, Batavia
Front end of a CW linac of the Project X contains a H- source, an RFQ, a medium energy transport line with the beam chopper, and a SC low-beta linac that accelerates H- from 2.5 MeV to 160 MeV. SC Single ' spoke Resonators (SSR) will be used in the linac, because Fermilab already successfully developed and tested a SSR for beta 0.21. Two manufactured cavities achieve 2-3 times more than design accelerating gradients. One of these cavities completely dressed, e.g. welded to helium vessel with integrated slow and fast tuners, and tested in CW and pulse regimes. Successful tests of beta=0.21 SSR give us a confidence to use this type of cavity for low beta (0.117) and for high- beta (0.4) as well. Both types of these cavities are under development. In present report the basic constrains, parameters, electromagnetic and mechanical design for all the three SSR cavities, and first test results of beta=0.21 SSR are presented.