LANL, Los Alamos, New Mexico
Given the increased concern over reliable, emission-free power, nuclear power has experienced a resurgence of interest. A sub-critical accelerator driven system (ADS) can drive systems that have either safety constraints (waste transmutation) or reduced fissile content (thorium reactor). The goals of an ADS are some or all of the following: 1) to significantly reduce the generation or impacts due to the minor actinides on the packing density and long-term radiotoxicity in the repository design, 2) preserve/use the energy-rich component of used nuclear fuel, and 3) reduce proliferation risk. ADS systems have been actively studied in Europe and Asia over the past two decades and renewed interest is occurring in the U.S. This talk will cover some of the history, possible applicable fuel cycle scenarios, and general issues to be considered in implementing ADS systems.
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
This review will cover in the time available as many as possible of the high intensity hadron accelerator projects worldwide. The range will be from spallation neutron sources to machines for neutrino physics and will include existing and proposed accelerators. The aim will be to explore parameter ranges, identify areas of commonality and highlight how experience in one project can be used to help solve challenges in others.
ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source has been operational for over three years, characterized by a rapid power ramp-up over the first two years and operation at a beam power of about one MW for the past year. Equipment reliability is a major concern at a user facility like SNS, and beam power has been limited primarily by equipment robustness to date. Beam loss is also a major concern, and is the primary driver in beam tuning. Many beam loss reductions are found empirically, and are not well understood. SNS is operating at the MW level with uncontrolled beam loss below the 1 W/m level, as required for hands on maintenance, and has not limited the operational beam power to date.
KEK, Ibaraki
The J-PARC facility consists of linac, 3 GeV RCS (Rapid Cycling Synchrotron), 50 GeV MR (Main Ring synchrotron, 30 GeV at the present) and three experimental facilities, the MLF (Material and Life science experimental Facility), the hadron experimental facility and the neutrino beam line. The RCS has started 120 kW beam delivery to the MLF (Material and Life science experimental Facility) since November 2009. The MR delivers 50 kW beam to the neutrino beam line by fast extraction and a few kW beam to the hadron facility by slow extraction. In this paper, status of the high intensity operation of the J-PARC accelerators is presented. Beam dynamics studies and our practical experience at the high power beam are discussed. In addition, future plans and strategies to increase the beam intensity are also presented briefly.
CERN, Geneva
The unprecedented design intensities of the LHC require several important advances in beam collimation. With its more than 100 collimators, acting on various planes and beams, the LHC collimation system is the biggest and most performing such system ever designed and constructed. The solution for LHC collimation is explained, the technical components are introduced and the initial performance is presented. Residual beam leakage from the system is analyzed and compared to simulations. It is shown that the observed leakage is in agreement with prior predictions. Measurements are presented which show that collimation efficiencies of better than 99.98 % have been measured with the 3.5 TeV proton beams of the LHC.
GSI, Darmstadt
Increasing the intensity of heavy ion beams in synchrotrons, especially in the low and intermediate energy range, requires a reduction of the charge state. With an increase of two orders of magnitude compared to the present intensity levels at GSI, the FAIR project is aiming for the highest heavy ion beam intensities world wide. Space charge limits and significant beam loss in stripper stages disable a continuation of the present high charge state operation. The presently achieved level of heavy ion beam intensities is in the order of 109 heavy ions per cycle. The FAIR intensities of 1011 heavy ions per cycle can only be reached by acceleration of U28+-ions instead of U73+-ions. Meanwhile, after partially completing the upgrade program of SIS18, the number of U28+-ions accelerated to the SIS100 injection energy, could be increased by a factor of 70. The specific challenge of the intermediate charge state operation is the high cross section for ionization in combination with gas desorption processes and the dynamic vacuum pressure. The achieved progress in minimizing the ionization beam loss underlines that the chosen technical strategies described in this report are appropriate.
IHEP Beijing, Beijing
CSNS (China Spallation Neutron Source) is a project under construction, which will be a unique facility in China for multi-disciplinary research using neutron scattering techniques. The CSNS accelerator complex is designed to deliver proton beams of 100 kW at Phase One, and progressively upgraded to 200 kW at Phase Two and 500 kW at Phase Three. The upgrading path in beam power is via the increase in linac energy and more accumulated particles in the RCS (Rapid Cycling Synchrotron). Beam losses are key in designing and operating the accelerator complex. Emittance growth, RF trapping loss, and injection/extraction are the major loss sources. The measures to reduce the loss rate and the collimation methods in the accelerators are presented in the talk. Some beam loading effects to the RF systems in the linac and in the RCS, and the uniformization of the beam spot at the spallation target by non-linear magnets are also mentioned.
LBNL, Berkeley, California
A Joint Task Force on Future Applications of Laser Acceleration, has been formed to develop a roadmap for laser technology for future accelerators. The taskforce is operating under the umbrella of ICFA (International Committee for Future Accelerators) and ICUIL (International Committee on Ultra-High Intensity Lasers). A first workshop was organized by the Task Force on April 8-10 (2010) at GSI (Darmstadt), with invited experts on high power laser technology as well as accelerator technology. The main topics were the laser performance needed for accelerator technology to support the most challenging present and future accelerator needs, as well as questions of laser architecture, laser material and optical components. Accelerator and light source representatives outlined the top level laser requirements for potential laser-based accelerator applications, i.e. colliders, light sources and medical applications. An overview of the outcome of this workshop will be presented, including a discussion on laser requirements for acceleration of electrons and ions.