Fermilab, Batavia, Illinois
Project X is a concept for an intense 8 GeV proton source that provides beam for the Fermilab Main Injector and an 8 GeV physics program. The source consists of an 8 GeV superconducting linac that injects into the Fermilab Recycler where multiple linac beam pulses are stripped and accumulated. The 8 GeV linac consists of a low energy front end possibly based on superconducting technology and a high energy end composed of ILC-like cryomodules.
Fermilab, Batavia, Illinois
While a beam is being bunched, a coherent synchrotron frequency grows from zero to a maximal value, crossing many synchro-betatron resonances of the bunch motion. If a related driving force is high enough, the beam can get unstable. This phenomenon is important at Fermilab Booster, presumably being driven by dispersion in the cavities. To stabilize the beam, high chromaticities are required.
ORNL, Oak Ridge, Tennessee
Beam phase synchronous oscillations and the damping curves of the SNS linac are investigated with linac models and measured with all the linac beam phase monitors. It provides a useful beam diagnostic solution to detect RF cavity phase and/or field amplitude errors in the linac with many independently phased cavities. And the phase damping curves predicted in the longitudinal model could also be utilized to analyze the longitudinal lattice of the superconducting linac, in which each cavity gradient varies widely from the nominal design and smooth the beam longitudinal focusing is very important to preserve beam emittance.
ORNL, Oak Ridge, Tennessee
The paper describes a usage of the XAL online model for transverse and longitudinal tuning of the SNS linac. Most of the SNS control room physics applications based on the XAL online model which allows synchronizing the model with an accelerator live state and using this model for tuning the machine. Peculiarities of applying of the simplest single particle mode of the model for orbit correction and longitudinal dynamics control of the SNS linac are discussed. The procedure of parameters finding, algorithms, and results are presented.
ORNL, Oak Ridge, Tennessee
Most recent beam dynamic studies of the Spallation Neutron Source linac, including the major beam loss reduction efforts in the normal conducting (nc) linac and in the superconducting linac (SCL), simulations and measurements of the longitudinal beam halos and the longitudinal acceptance at the entrance of the SCL are discussed. Oscillation of beam centroid around the linac synchronous phase and the beam phase adiabatic damping curves in the SNS linac are investigated with the linac longitudinal models and measured with all the linac beam phase monitors.
ANL, Argonne, Illinois
Fermilab, Batavia, Illinois
Superconducting (SC) technology is the only option for CW linacs and is also an attractive option for pulsed linacs. SC cavities are routinely used for proton & H-minus beam acceleration above 185 MeV. Successful development of SC cavities covering the lower velocity range (down to 0.03c) is a very strong basis for the application of SC structures in the front ends of high energy linacs. Lattice design and related high-intensity beam physics issues in a ~400 MeV linac that uses SC cavities will be presented in this talk. In particular, axially-symmetric focusing by SC solenoids provides strong control of beam space charge and a compact focusing lattice. As an example, we discuss the SC front end of the H-minus linac for the High Intesity Neutrino Source (HINS) and Project X.
IAP, Frankfurt am Main
GSI, Darmstadt
The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept is described in detail. A KONUS period consists of a quadrupole triplet or a solenoid lens, a rebuncher section at negative synchronous phase and a multi cell zero degree synchronous particle main acceleration section. This concept is especially effective when applied for accelerator designs using H-mode resonators with ‘slim’ drift tubes which carry no focusing elements. The definition and typical ranges of KONUS lattice parameters are discussed on a general level, as well as on the basis of examples for realized or planned high current accelerators, like the GSI High Current Injector (HSI), the 70 mA, 3-70 MeV Proton Injector for the FAIR Facility and our proposal of a 125 mA D+, 5-40 MeV superconducting CH-DTL section for the International Fusion Materials Irradiation Facility (IFMIF).
GSI, Darmstadt
IAP, Frankfurt am Main
The FAIR facility at GSI requires a dedicated proton injector for the production of secondary high intensity antiproton beams. This 325 MHz, 70 MeV machine will be the fist linac based on CH cavities operated with Konus beam dynamics. Two different options for the beam dynamics layout are under investigation including loss and error studies. Finally different RFQ output distribution are used to evaluate the injection current into the main linac.
Soreq NRC, Yavne
In this study we examine a lattice for the SARAF superconducting (SC) linac at the low velocity β range. The SC Half Wave Resonator cavities in the first cryostat have been optimized for a geometric β=0.09 and hence the β=0.0567 ions coming from the RFQ are mismatched. We developed a semi adiabatic tuning method for the low β side of the SC linac. The guidelines were derived from a study of two linac lattices that were considered for the SARAF 40 MeV proton and deuteron linac, extended up to 60 MeV for the low energy part of the EURISOL driver. Simulations were made using the TRACK and GPT codes. The lattices were tested for energy gain along the linac, emittance growth and acceptance. Further, error runs in GPT using a tail emphasis technique to enhance statistics by focusing on the bunch tail allowed us to examine compatibility of the lattices with hands-on maintenance requirements. We find our study relevant for other linacs that start with SC cavities right after the RFQ, such as SPIRAL2, and maybe IFMIF too, which are designed to start with similar β mismatch at the low β range.
ORNL, Oak Ridge, Tennessee
With the increase of average power of present and future high intensity proton rings and rapid progress of laser technology, laser-assisted stripping become a real alternative for carbon foils that are used for charge-exchange injection. High efficiency laser stripping, achieved experimentally at Spallation Neutron Source in Oak Ridge, TN, paved the way to full scale devices of such type. This paper presents overview of machines and choices of parameters for future powerful accelerators with possible laser stripping use.
KEK, Ibaraki
Beam commissioning of J-PARC Main Ring (MR) has been started in May, 2008. The 3-GeV beams extracted from the rapid cycling synchrotron (RCS) are injected into the MR and captured by rf, and then extracted to a 3-GeV beam dump. In this paper, we present results of the first-stage commissioning run from May to June 2008. After five months shutdown for installation of fast extraction and slow extraction devices, the second-stage commissioning run will be started in December 2008.
University of the Basque Country, Faculty of Science and Technology, Bilbao
Bilbao, Faculty of Science and Technology, Bilbao
Fundación TEKNIKER, Eibar (Gipuzkoa)
Elytt Energy, Madrid
A revised layout for the proton linear accelerator as proposed by the European Spallation Source-Bilbao (Spain) bid to host the installation is here described. The new machine concept aims to incorporate advances which have been registered within the ï¬eld of high power accelerators during the last decade. Particularly relevant are the ongoing works within Magnetic Fusion activities (IFMIF/EVEDA), waste transmutation (EUROTRANS) or radioactive ion beam (EURISOL) and heavy-ion physics (FAIR, SPIRAL2) which have lead to signiï¬cantly shorter accelerators incorporating state-of-the-art technology which mainly replaces decades-old copper drift-tubes, coupled-cavity LINACs or some other accelerating structures employed for energies beyond 50 MeV or so by superconducting cavities (SC) of a wholly new kind. The design of such a new accelerator layout will be critically dependent upon the development and/or adaptation of low β superconducting cavities already developed for some of the referred projects into those adequate for pulsed operation and high duty cycle.
The authors wish to acknowledge extremely fruitful discussions held with scientists from CEA/SACLAY, IPN/ORSAY as well as from the ISIS Spallation Neutron Source.
CERN, Geneva
The construction of a Superconducting Proton Linac is planned at CERN during the next decade. It is foreseen to be constructed in two stages: a low duty cycle, low-power linac (LPSPL) as an injector for a new 50 GeV synchrotron (PS2) replacing the present PS, which could be upgraded to a high-duty cycle, high-power linac (HPSPL), for the needs of future facility(ies) requiring a multi-MW beam power. In this paper we present the criteria which were used to choose the frequency, gradient, and cryogenic temperature of the SPL. Since these questions are common to other proposed high-power proton linacs, we propose a generalization of the arguments. The various design options are discussed as well as their impact on beam dynamics, cavity performance, power consumption, cryogenics, overall efficiency, and cost of the facility.
LANL, Los Alamos, New Mexico
We are developing a compact deuteron-beam accelerator up to the energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IH-PMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.
Fermilab, Batavia, Illinois
The High Intensity Neutrino Source (HINS) program at Fermilab will demonstrate new technologies suitable for the low-energy front-end of a high intensity H- linac based on independently phased superconducting resonators (driven by a single power source). Eighteen β. = 0.21 superconducting single spoke resonators, operating at 325 MHz with an nominal accelerating field of 10 MV/m, comprise the first stage of the linac cold section. For two prototype resonators, we report on the construction phases and the comparison of low gradient RF measurements with calculations. After Buffered Chemical Polishing and High Pressure Rinse at Argonne, one resonator has undergone high gradient RF testing at 2.0° 4.5°Kelvin in the Vertical Test Stand (VTS) at Fermilab. We present measurements from the VTS tests, including BCS resistance and the quality factor as a function of accelerating field. In order to help understand multipacting and field emission, RTD temperature sensors were mounted on the exterior walls of the cavity, and x-ray sensing diodes were mounted near the cavity in the liquid helium bath. The resonator reached an accelerating field of 13.4 MV/m.
Fermilab, Batavia, Illinois
High intense hadron beams of > 2 MW beam power are a key element for the new proposed Neutrino experiments at Fermilab. Therefore a new beam facility, called Project-X, is under discussion. We will present requirements, and first conceptual ideas for beam instrumentation and diagnostics, and the related R&D initiatives taking place in the high intense test accelerators, currently under construction. First results of beam profile measurements using OTR screens and laser wires are shown.
ANL, Argonne, Illinois
CERN, Geneva
The International Program Committee of the Workshop and its Chairman have charged us with the following three questions:
- Recent trends in high-intensity proton/ion beam facilities?
- Critical challenges and key research areas for substantial beam power increases?
- Necessary improvements in theory and simulation tools?