IPN, Orsay
GANIL, Caen
LPSC, Grenoble
The SPIRAL2 project, installed in GANIL for Radioactive Ion Beam physics purposes requires the manufacturing of a multi beam driver. This driver is based on a superconducting Linac featuring two 88 MHz Quarter Wave Resonator families. IPN Orsay is in charge of the study and the assembly of the 7 high energy (beta = 0.12) cryomodules. Each cryomodule is composed of two QWRs, specified to operate at 4.2 K with a nominal accelerating gradient of 6.5 MV/m. A first qualifying cryomodule has been manufactured and tested at the beginning of 2008 in order to validate the resonator and the cryostat design before launching the serial production of the 6 remaining cryomodules. The paper presents the main results of this test and the cryomodule design in its final version.
Kyoto ICR, Uji, Kyoto
KEK, Ibaraki
Inspections of superconducting rf cavities seem essential in achieving high achieving gradient. The inspection of interior surface of a superconducting rf cavity with high enough resolution to find defects more than several tens microns is achieved by our high resolution camera system. This system revealed undiscovered defects at just inner sides of the locations predicted by passband-mode and thermometry measurements. This system will help to improve cavity fabrication processs and their yield. This system will be delivered world wide for that purpose. We are planning to widen our activity in this field: developments of new termometry system with easy installation and less cabling and high sensitivity Eddy Current Surface Inspection system for bare niobium sheets. The detailed systems and some preliminary data obtained from the systems will be presented.
CLASSE, Ithaca, New York
Funding: Work is supported by the National Science Foundation grant PHY 0131508.
Two high power 1300 MHz rf systems have been developed for the Cornell University ERL Injector. The first system, based on a 16 kWCW IOT transmitter, is to provide rf power to a buncher cavity. The second system employs five 120 kWCW klystrons to feed 2-cell superconducting cavities of the injector cryomodule. The sixth, spare klystron is used to power a deflecting cavity in a pulsed mode for beam diagnostics. A digital LLRF control stem was designed and implemented for precise regulation of the cavities' field amplitudes and phases. All components of these systems have been recently installed and commissioned. The first operational experience with the systems is discussed.
DESY, Hamburg
JLAB, Newport News, Virginia
Funding: This manuscript has been partially authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The technology of forming multi-cell seamless niobium cavities has been developed at DESY within the European CARE (Coordinated Accelerator Research in Europe) program. Three cell units have been manufactured successfully and a 9-cell cavity has recently been completed from three sub-sections and will be tested in the near future. Meanwhile, we have equipped two 3-cell units – one center unit of a 9-cell cavity and one end-unit – with niobium beam pipes, have tuned these units and carried out cryogenic rf tests after standard bcp surface treatments had been applied to these cavities. In addition, we will take temperature maps with Jlab's two-cell thermometry system; since in cavities fabricated by 'standard' methods such as deep drawing of half cells and electron beam welding cavity performance limitations have often been found at or near equator welds. It will be of particular interest to compare the seamless cavity quench locations to those from standard cavities. This contribution will report about the cryogenic test results and the T-mapping findings.
DESY, Hamburg
The rf stations for the FLASH linear accelerator at DESY provide rf power up to more than 5 MW, 1.3 ms and 10 Hz at 1.3 GHz for forty-eight superconducting cavities grouped into six cryogenic modules and for one normal conducting rf gun. A WR650 waveguide distribution system distributes the power generated by five active rf stations using 5 MW single beam and a 10 MW multibeam klystron to the cavities and the gun. Since FLASH is based on the Tesla Test Facility, TTF, a number of different distribution layouts for the different modules and the gun have been developed and used over the years in terms of type of components and distribution scheme. This paper presents the layout and summarizes the experience with the existing waveguide distribution system.
