AES, Medford, NY, USA
Stony Brook University, Stony Brook, USA
BNL, Upton, Long Island, New York, USA
Advanced Energy Systems, Inc. is under contract to Stony Brook University to design and build a 704 MHz, high current, Superconducting RF (SRF) five cell cavity to be tested at Brookhaven National Laboratory. This cavity is being designed to the requirements of the SPL at CERN while also considering operation with electrons for a potential RHIC upgrade at Brookhaven. The β=1 cavity shape, developed by Brookhaven, is designed to accelerate 40 mA of protons at an accelerating field of 25 MV/m with a Q0 > 8·109 at 2K while providing excellent HOM damping for potential electron applications. 10-CFR-851 states that all pressurized vessels on DOE sites must conform to applicable national consensus codes or, if they do not apply, provide an equivalent level of safety and protection. This paper presents how the 2007 ASME Boiler and Pressure Vessel Code Section VIII, Division 2 requirements can be used to satisfy the DOE pressure safety requirements for a non-code specified material (niobium) pressure vessel.
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
AES, Medford, NY, USA
BNL, Upton, Long Island, New York, USA
Over a dozen CESR-B Type SRF cryomodules have been implemented in advanced accelerators around the world. The cryomodule incorporates a niobium cavity operating in liquid helium at approximately 1.2 bar and at 4.5 K, and therefore, is subjected to a differential pressure of 1.2 bar to the beam vacuum. Over the past few decades niobium RRR values have increased, as manufacturing processes have improved, resulting in higher purity niobium and improved thermal properties. Along with these increases may come a decrease of yield strength, therefore, prior designs such as CESR-B, must be evaluated at the newer strength levels when using the newer high purity niobium. In addition to this the DOE directive 10CFR851 requires all DOE laboratories to provide a level of safety equivalent to that of the ASME Boiler and Pressure Vessel codes. The goal of this work was to analyze the CESR-B Type cavity and compare the results to ASME pressure vessel criteria and where necessary modify the design to meet the code criteria.
AES, Medford, NY, USA
BNL, Upton, Long Island, New York, USA
JLAB, Newport News, Virginia, USA
AES, Medford, NY, USA
ANL, Argonne, USA
TechSource, Santa Fe, New Mexico, USA
The upgrade for the ATLAS facility is designed to increase the efficiency and intensity of beams for the user facility*, **. This will be accomplished with a new CW normal conducting RFQ, which will increase both transverse and longitudinal acceptance of the LINAC. This RFQ must operate over a wide range of power levels to accelerate ion species from protons to uranium. The RFQ design is a split coaxial structure and is made of OFE copper. The geometry of the design must be stable during operation. Engineering studies of the design at different RF power levels were conducted to ensure that the geometry requirements were met. Frequency shift analysis was also completed to determine the effects of high power levels. Thermal stress analysis was completed to show that the structure frequency is repeatable.
*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
ORNL, Oak Ridge, Tennessee, USA
SNS electrical systems have been operational for 4 years. System availability statistics and improvements are presented for ac electrical systems, dc and pulsed power supplies and klystron modulators
ORNL, Oak Ridge, Tennessee, USA
ORNL RAD, Oak Ridge, Tennessee, USA
SLAC, Menlo Park, California, USA
Photonic crystal fibers (PCFs) represent a class of optical fibers which have a wide spectrum of applications in the telecom and sensing industries. Currently, the Advanced Accelerator Research Department at SLAC is developing photonic bandgap particle accelerators, which are photonic crystal structures with a central defect used to accelerate electrons and achieve high longitudinal electric fields. Extremely compact and less costly than the traditional accelerators, these structures can support higher accelerating gradients and will open a new era in high energy physics as well as other fields of science. Based on direct laser acceleration in dielectric materials, the so called photonic band gap accelerators will benefit from mature laser and semiconductor industries.
SLAC, Menlo Park, California, USA
