Fermilab, Batavia, USA
Northern Illinois University, DeKalb, Illinois, USA
A superconducting RF accelerator test facility is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beamlines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 810 MeV electron beam with ILC beam intensity. Expansion plans of the facility are underway that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. In addition to testing accelerator components, this facility will be used to test RF power equipment, instrumentation, LLRF and controls systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.
BNL, Upton, Long Island, New York, USA
JLAB, Newport News, Virginia, USA
AES, Medford, NY, USA
The Brookhaven National Laboratory (BNL) 5-cell, 703 MHz superconducting RF accelerating cavity has been installed in the high-current energy recovery linac (ERL) experiment. This experiment will function as a proving ground for the development of high-current machines in general and is particularly targeted at beam development for an electron-ion collider (eRHIC). The cavity performed well in vertical tests, demonstrating gradients of 20 MV/m and a Q0 of 1010. Here we will present its performance in the horizontal tests, and discuss technical issues involved in its implementation in the ERL.
Fermilab, Batavia, USA
The commissioning of two cryomodule components is underway at Fermilab’s Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule #1 (CM1) and Capture Cavity II (CC2) which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.
Fermilab, Batavia, USA
The low-beta section of the linac being considered for Project X at Fermilab contains several styles of 325 MHz superconducting single spoke cavities and solenoid based focusing lenses, all operating at 2 K. Each type of cavity and focusing lens will eventually be incorporated into the design of cryomodules unique to various sections of the linac front end. This paper describes the design of a multiple-cavity and solenoid cryomodule being developed to test the function of each of the main cryomodule systems – cryogenic systems and instrumentation, cavity and lens positioning and alignment, conduction-cooled current leads, magnetic shielding, cold-to-warm beam tube transitions, interfaces to interconnecting equipment and adjacent modules, as well as evaluation of overall assembly procedures.
SLAC, Menlo Park, California, USA
We have been developing an X-band cryogenic RF material testing system since 2005. By measuring the Q of a hemispherical cavity with the material sample at is flat interchangeable bottom, the system is capable to characterize the surface resistance of different materials at the temperature of 3-300K, as well as the quenching RF magnetic field of the superconducting samples at different temperatures. Using a SLAC X-band 50 MW klystron, the system can measure the quenching H-field of up to 300mT under current setup, with the possibility of further enhancement by changing the RF distribution configuration.
Meyer Tool & MFG, Oak Lawn, Illinois, USA
NSRRC, Hsinchu, Taiwan
NSRRC, Hsinchu, Taiwan
NSRRC, Hsinchu, Taiwan
ANL, Argonne, USA
Short-period superconducting undulators (SCUs) are presently being developed for the Advanced Photon Source. Field measurements of the SCUs will be performed at 4.2 K and near 300 K, so temperature-dependent calibration of the Hall probes is necessary. The sensitivity of the Hall probes has been measured at temperatures from 5 K to 320 K over a magnetic field range of ␣1.5 T. It was found that the sensitivity increased as the temperature decreased from 300 K to about 150 K. A specially designed probe assembly, with three Hall sensors for measuring both the horizontal and vertical field components, has been calibrated. The techniques for doing the calibration and the measurement results at various temperatures will be presented.
BNL, Upton, Long Island, New York, USA
A 56 MHz Superconducting RF Cavity is being constructed for the RHIC collider. This cavity is a quarter wave resonator that will be operated at 4.4K. The cavity requires an extreme quiet environment to maintain its operating frequency. The cavity besides being engineered for a mechanically quiet system, also requires a quiet cryogenic system. Liquid helium is taken from RHIC's main helium 3.5 atm, 4.9K supply header to supply this sub-system and the boil-off is return to a separate local compressor system nearby. To acoustically separate the cryogenics' delivery and return lines, a condenser/boiler heat exchanger is used to re-liquefy the helium vapor generated by the cavity. A system description and operating parameters is given about the cryogen delivery sub-system.
BNL, Upton, Long Island, New York, USA
A small cryogenic system and warm helium vacuum pumping system provides cooling to the Energy Recovery Linac's (ERL) cryomodules, a 5-cell cavity and an SRF gun, and a large Vertical Test Dewar. The system consist of a model 1660S PSI (KPS) plant, a 4000 liter storage dewar, subcooler, wet expander, 50 g/s main helium compressor and 170 m3 storage tank. A system description and operating plan is given of the cryogenic plant and cryomodules
BNL, Upton, Long Island, New York, USA
A vertical facility has been constructed to test SRF cavities and can be utilized for other use. The liquid helium volume for the large vertical dewar is approximate 84 inches tall by 40 inches diameter with a working clear inner diameter of 38 inch with the inner cold magnetic shield system installed. For radiation enclosure, the test dewar is situated inside a concrete block structure. The structure is above ground and is accessible from the top, and has a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth is also available for testing of smaller cavities in 2 smaller dewars.
BNL, Upton, Long Island, New York, USA
In order to cool the superconducting magnets in RHIC, its helium refrigerator distributes 4.5 K helium throughout the tunnel via a series of distribution and return lines. The worst case for failure would be a release from the magnet distribution line, which operates at 3.5 to 4.5 atmospheres and contains the energized magnet bus. Should the bus insulation system fail or an electrical connection open, there is the potential for releasing up to 70 MJoules of stored energy. Studies were done to determine release rate of the helium and the resultant reduction in O2 concentration in the RHIC tunnel and service buildings. Equipment and components were also reviewed for reliability and the effects of 10 years of operations. Modifications were made to reduce the likelihood of failure and to reduce the amount of helium gas that could be released into tunnels and service buildings while personnel are present. This paper describes the issues reviewed, the steps taken, and remaining work to be done to reduce the hazards.
ANL, Argonne, USA
BINP SB RAS, Novosibirsk, Russia
Short-period superconducting undulators are being developed as part of the Advanced Photon Source (APS) upgrade program. The first test device is in fabrication. Before installation into the storage ring, the magnetic performance of the undulators will be characterized. The magnetic measurement facility routinely used for measuring and tuning conventional undulators cannot be employed for superconducting devices, so a new measurement system is being designed and built. The system is mechanically mounted on the undulator cryostat and uses a heated tube in the cold undulator bore to guide a Hall probe or measuring coils. A specially designed three-Hall sensor assembly allows measurement of the vertical and horizontal components of the magnetic field and the determination of the height of the magnetic midplane. A set of measuring coils is mounted on carbon-fiber tubes that can be translated and rotated in the undulator bore to measure the field integrals and their multipole components. The design of the measurement system and its construction status is described in this paper.
AES, Medford, NY, USA
ANL, Argonne, USA
An energy upgrade to the heavy-ion accelerator ATLAS at Argonne Lab is progressing*,**. The plans include replacing split-ring cavities with high performance quarter wave resonators. The new 72.75 MHz resonators are designed for optimum ion velocity β=.077 and a record high accelerating voltage of 2.5 MV by modifying the top geometry and reducing the peak surface fields. This new cavity has a longer center conductor than the 109 MHz cavities previously built by ANL with AES assistance, this and the other geometry changes add new engineering requirements to the design. This paper presents the engineering studies that were performed to resolve new issues. These studies include determining structural frequencies of the center conductor and stiffening methods, resonator frequency sensitivity to helium pressure fluctuations, and determining stress levels due to pressure and slow tuning. Evaluation of fast piezoelectric tuner frequency shift to tuner load was also performed and the local cavity shape was optimized based on these results.
* P.N. Ostroumov, et.al, “A New Atlas Efficiency and Intensity Upgrade Project,” SRF2009, tuppo016
** P.N. Ostroumov, et.al., “Efficiency and Intensity Upgrade of the Atlas Facility,” LINAC 2010, MOP045
Tech-X, Boulder, Colorado, USA
JLAB, Newport News, Virginia, USA
Nuclear physics accelerators are powered by microwaves which must travel in waveguides between room-temperature sources and the cryogenic accelerator structures. The ohmic heat load from the microwaves is affected by the temperature-dependent surface resistance and in turn affects the cryogenic thermal conduction problem. Integrated EM & thermal analysis of this difficult non-linear problem is now possible with the VORPAL finite-difference time-domain simulation tool. We highlight thermal benchmarking work with a complex HOM feed-through geometry, done in collaboration with researchers at the Thomas Jefferson National Accelerator Laboratory, and discuss upcoming design studies with this emerging tool. This work is part of an effort to generalize the VORPAL framework to include generalized PDE capabilities, for wider multi-physics capabilities in the accelerator, vacuum electronics, plasma processing and fusion R&D fields, and we will also discuss user interface and algorithmic upgrades which facilitate this emerging multiphysics capability.
NSRRC, Hsinchu, Taiwan
BNL, Upton, Long Island, New York, USA
There are 60 12×150A current leads distributed in 6 RHIC service buildings; each current lead delivers power supply current from room temperature to cryogenic temperature in RHIC. Due to the humid environment, condensation frequently occurs and ice was quickly formed during operation, especially during an extensive storage period. This condition generated warnings and alarms that personal had to respond to, in order to provide temporary solutions, to keep the machine operational. A temperature control system was designed to avoid such occasions. We will discuss design, implementation and some results of this design in this paper.
NSRRC, Hsinchu, Taiwan
SSRF, Shanghai, People's Republic of China
BNL, Upton, Long Island, New York, USA
Both In-Vacuum Undulators (IVU) and Cryogenic Permanent Magnet Undulators (CPMU), each important to third generation light sources, are best characterized in their operating environment. To create a precise Hall probe map of an IVU/CPMU (IVU hereafter), an In-Vacuum Magnetic Measurement (IVMM) System is proposed. Point-by-point measurement of field and trajectory error at operating conditions informs corrective tuning. A novel design concept for a universal IVMM System has been developed and explored. The IVMM seals to the rectangular UHV-flange of the IVU and shares its common vacuum space. Moreover, a modular design permits a range of IVU of varying magnetic length to be mapped with a single IVMM System, and is thus cost effective when multiple IVU of different configuration are planned. Here we review aspects of the modular IVMM design concept.