Development and Testing of a 3.9 GHz Third Harmonic Superconducting RF System at Fermilab (original) (raw)

RF design and processing of a power coupler for third harmonic superconducting cavities

2007 IEEE Particle Accelerator Conference (PAC), 2007

The FLASH user facility providing free electron laser radiation is built based on the TTF project at DESY. Fermilab has the responsibility for the design and processing of a third harmonic, 3.9 GHz, superconducting cavity which is powered via a coaxial power coupler. Six power couplers have been manufactured at CPI after successful design of the power coupler including RF simulation, multipacting calculation, and thermal analysis. The power couplers are being tested and processed with high pulsed power in an elaborate test stand at Fermilab now. This paper presents the RF design and processing work of the power coupler.

ELECTRONIC SYSTEM FOR SUPERCONDUCTING RF MODULE AT THE SYNCHROTRON RADIATION RESEARCH CENTER

The electron storage ring at the Synchrotron Radiation Research Center, as a third-generation light source, is routinely operated with a maximum beam current of 200mA with two DOIRS cavities. One major machine upgrade is being undertaken at SRRC. It involves replacing the existing Doris cavities with a single CESR- III superconducting module. A maximum beam current of 500 mA in a high-order-mode under well damped conditions is expected, and will significantly enhance the spectral brightness and stability of beam. Commissioning is scheduled for the spring of 2003. Two SRF modules of the Cornell design will be delivered from ACCEL. The associated electronics protect against the window arcing and cavity quench, and support cryogenic control of cryostat conditions. An existing low level RF system is being modified and expanded for functional integration with the SRF modules. The electronic integration of the SRF modules is reported.

Recent progress in the superconducting RF Program at TRIUMF/ISAC

Physica C: Superconductivity, 2006

The first phase of the ISAC-II superconducting accelerator has recently been commissioned. The heavy ion linac adds 20MV to the 1.5MeV/u beam injected from the ISAC post accelerator. The linac is composed of five cryomodules; each cryomodule housing four 106 MHz quarter wave resonators ( = 0 .057, 0.071) and one 9 T superconducting solenoid all operating at 4K. On-line performance has confirmed cw cavity operation at a peak surface field in excess of 35 MV/m. Performance after 18 months of operation and a full thermal cycle during the annual shutdown shows very little degradation in performance. The second phase of the program will see the installation of a further 20 MV of 141 MHz quarter wave cavities with ( =0.11. Two prototypes of the cavities are now in production. The mechanical drive for the coupling loop of the Phase I cavities is now being modified to improve the motion as part of the Phase II hardware development. TRIUMF is proposing to build a 50MeV electron driver as part of the next five year plan. Consequently plans are now underway to upgrade the SRF lab to support developments at 1.3 GHz. The report will summarize all aspects of the program.

First Operation of a Superconducting RF Electron Test Accelerator at Fermilab

2015

A test accelerator utilizing SRF technology recently accelerated its first electrons to 20 MeV at Fermilab. Foreseen enhancements will make acceleration to 300 MeV possible at a maximum beam power of 80 kW. A summary of commissioning steps and first experiments as well as current beam parameters compared to design is presented. Plans for expansion and the future physics program are also summarized.

Superconducting RF Development at Nuclear Science Centre

Proceedings of the 2005 Particle Accelerator Conference

A Superconducting Linac is being installed as a booster for the 15 UD Pelletron accelerator at Nuclear Science Centre (NSC). The accelerating structure for this linac is a Nb QWR cavity, designed and fabricated as a joint collaboration between NSC and ANL, USA. Initial cavities required for the first linac module were fabricated at ANL. For fabrication of cavities required for future modules a Superconducting Resonator Fabrication Facility has been set up at NSC. Three quarter wave resonator (QWR) cavities have been fabricated using the in-house facility. This facility has been used for repairs on the resonators which sprung leaks. Fabrication of fifteen resonators for the second and third linac modules is under progress. Eight resonators along with a superconducting solenoid has been installed in the first linac cryostat and tested for energy gain with a pulsed beam of 90 MeV Si from the Pelletron. Acceleration of the ions to 96 MeV was measured downstream and beam transmission through the linac was measured to be 1 00%.

RF regulation with superconducting cavities and beam operation using a frequency shifted cavity

2022

The free-electron laser FLASH at DESY and the European XFEL are operated with superconducting radio frequency cavities and supply beam to several user experiments. The switching time between experiments is limited to dozens of microseconds. This contribution will show a regulation with a frequency shifted superconducting cavity to manipulate and change the accelerating properties of electron bunches with 250 kHz.The main challenge of the concept presented in this contribution can be summarized in this statement: finding a way to modulate the energy of individual bunches in a single-source multiple-cavity scheme for a potential CW upgrade of the EuXFEL.

Development of the Superconducting 3.9 GHz Accelerating Cavity at Fermilab

Proceedings of the 2005 Particle Accelerator Conference, 2005

A superconducting third harmonic 3.9 GHz accelerating cavity was proposed to improve the beam quality in the TTF-like photoinjector . Fermilab has developed, built and tested several prototypes, including two copper 9-cell cavities, one niobium 3-cell cavity, and one 9-cell cavity. The helium vessel and frequency tuner for the 9-cell cavity was built and tested as well. In cold tests, we achieved a peak surface magnetic field of ~100mT, well above the 70mT specification. The accelerating gradient was likely limited by thermal breakdown. Studies of the higher order modes in the cavity revealed that the existing cavity design with two HOM couplers will provide sufficient damping of these modes. In this paper we discuss the cavity design, results of the studies and plans for further development.

Production and Test Results of Superconducting 3.9-GHz Accelerating Cavity at Fermilab

IEEE Transactions on Applied Superconductivity, 2007

The 3rd harmonic 3.9 GHz accelerating cavity was proposed to improve beam performances for TTF-FEL facility. In the frame of collaboration Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the International Linear Collider (ILC) accelerator test facility. In this paper we will discuss the status of the cavity and coupler production and the first result of cavity tests. It is hoped that this project will be completed during the first half of 2007 and the cryomodule delivered to DESY in this time span.

Application of rf superconductors to linacs for high-brightness proton beams

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1989

A series of superconducting structures for the acceleration of high-current ion beams is being developed, and two prototype Nb cavities are under construction. These cavities operate in a frequency-velocity range which, for superconducting structures, has been little explored: frequencies of 0.4 GHz to more than 1 GHz, and velocities of 0.1~ to 0.5~. Issues discussed include: need for strong beam loading ( -104), need for strong focusing elements located close to the cavities, minimization of beam impingement and beam instabilities.

Report on Superconducting RF Activities at CERN from 2001 to 2003

2003

The main project on superconducting RF at CERN in the period from 2001 to 2003 has been the 400 MHz SC system for the LHC. Five modules, each containing four single-cell niobium (Nb) sputtered cavities, have been assembled and low-power tested at room temperature and at 4.5 K. Production of the first four power couplers has been delayed but high-power