INFN/LNL, Legnaro (PD), Italy
FRIB, East Lansing, Michigan, USA
JLAB, Newport News, Virginia, USA
The superconducting driver and post-accelerator linacs of the FRIB project, the large scale radioactive beam facility under construction at MSU, require the construction of about 400 low-beta Quarter-wave (QWR) and Half-wave resonators (HWR) with four different optimum velocities. 1st and 2nd generation prototypes of β=0.041 and 0.085 QWRs and β=0.53 HWRs have been built and tested, and have more than fulfilled the FRIB and ReA design goals. The present cavity surface preparation at MSU allowed production of low-beta cavities nearly free from field emission. The first two cryostats of β=0.041 QWRs are now in operation in the ReA3 linac. A 3rd generation design of the FRIB resonators allowed to further improve the cavity parameters, reducing the peak magnetic field in operation and increasing the possible operation gradient , with consequent reduction of the number of required resonators. The construction of the cavities for FRIB, which includes three phases for each cavity type (development, pre-production and production runs) has started. Cavity design, construction, treatment and performance will be described and discussed.
Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics.
FRIB, East Lansing, Michigan, USA
JLAB, Newport News, Virginia, USA
Michigan State University is currently testing prototype and production cavities for two accelerator projects. 80.5 MHz β=0.085 quarter wave resonators (QWR) are being produced as part of a cryomodule for ReA3. 322 MHz β=0.53 half wave resonators (HWR) are being prototyped for a driver linac for the Facility for Rare Isotope Beams. This paper will discuss test results and how different cavity preparations effect cavity performs. Also various diagnostics methods have been developed, such as second sound quench location determination, and temperature mapping to determine hot spots from defects and multipacting location.
JLAB, Newport News, Virginia, USA
CEBAF 12GeV upgrade project includes 80 new 7-cell cavities to form 10 cryomodules. Each cavity underwent RF qualification at 2 Kelvin using a high power accelerating gradient test and an HOM survey in JLab’s Vertical Testing Area (VTA) before cavity string assembly. In order to ensure consistently high quality data, updated cavity testing procedures and analysis were implemented and used by a group of 10 VTA operators. For high power tests, a cavity testing procedure was developed and used in conjunction with a LabVIEW program to collect the test data. Additionally while the cavity was at 2K, an HOM survey was performed using a network analyzer and a combination of Excel and Mathematica programs. Data analysis was standardized and an online logbook, Pansophy, was used for data storage and mining. The Pansophy system allowed test results to be easily summarized and searchable across all cavity tests. In this presentation, the CEBAF 12GeV upgrade cavity testing procedure, method for data analysis, and results reporting results will be discussed.
JLAB, Newport News, Virginia, USA
The CEBAF accelerator, a recirculating CW electron accelerator that is currently operating at Jefferson Laboratory, is in the process of having 10 new cryomodules installed to allow for the maximum beam energy to be increased from 6 GeV to 12 GeV. This upgrade required the fabrication, processing and RF qualification of 80, seven cell elliptical SRF cavities, a process that was completed in February 2012. The RF performance achieve in the vertical testing dewars has exceeded the design specification by ~25% and is a testament to the cavity design and processing cycle that has been implemented. This paper will provide a summary of the cavity RF performance in the vertical tests, as well as review the overall cavity processing cycle and duration for the project.
JLAB, Newport News, Virginia, USA
The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is producing ten 100+MV SRF cryomodules (C100) as part of the CEBAF 12 GeV Upgrade Project. Once installed, these cryomodules will become part of an integrated accelerator system upgrade that will result in doubling the energy of the CEBAF machine from 6 to 12 GeV. This paper will present a complete overview of the C100 cryomodule production process. The C100 cryomodule was designed to have the major components procured from private industry and assembled together at Jefferson Lab. In addition to measuring the integrated component performance, the performance of the individual components is verified prior to being released for production and assembly into a cryomodule. Following a comprehensive cold acceptance test of all subsystems, the completed C100 cryomodules are installed and commissioned in the CEBAF machine in preparation of accelerator operations. This overview of the cryomodule production process will include all principal performance measurements, acceptance criterion and up to date status of current activities.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.
JLAB, Newport News, Virginia, USA
The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of ten new 100 MeV cryomodules and RF systems. The superconducting RF cavities are designed to be operated CW at a maximum accelerating gradient of 19.2 MV/m. To support the higher gradients and higher QL (~ 3x107), a new RF system has been developed and is being installed to power and control the cavities. The RF system employs digital control and 13 kW klystrons. Recently, two of these cryomodules and associated RF hardware and software have been installed and commissioned in the CEBAF accelerator. Electrons at currents up to 150 μA have been successfully accelerated and used for nuclear physics experiments. This paper reports on the commissioning and operation of the RF system and cryomodules.