BNL, Upton, Long Island, New York
Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
IMP, Lanzhou
The vacuum system of HIRFL is a large and complex system. HIRFL consists of two ECR ion sources, a sector focus cyclotron (SFC), a separate sector cyclotron (SSC) and a multipurpose cooling storage ring system which has a main ring (CSRm) and an experiment ring (CSRe). Several beam lines connect these accelerators together and transmit various heavy ion beams to more than 10 experiment terminals. According to the requirements of the ion acceleration and ion lifetime, the working pressure in each accelerator is different. SFC is nearly 50 years old. After upgrade, the working pressure in SFC is improved from 10E-6mbar to 10E-8mbar. The pressure in SSC which was built in 1980s reaches the same level. The cooling storage ring system with a length of 500m came into operation in 2007. The average pressure in CSRm and CSRe is 5E-12mbar and 8E-12mbar respectively. Different designs were adopt for vacuum system of dozens beam lines to meet various experiment terminals requirement. For instance, some shockproof measures have to be taken for the heavy ion microbeam facility. A clean and large throughput differential pumping system was built for the Gas-filled Recoil Separator and so on.
PPPL, Princeton, New Jersey
HCL, Cambridge, Massachusetts
PU, Princeton, New Jersey
Funding: Research supported by the U.S. Department of Energy.
The evaluation of ion-atom charge-changing cross sections is needed for many accelerator applications. A classical trajectory Monte Carlo (CTMC) simulation has been used to calculate ionization and charge exchange cross sections. For benchmarking purposes, an extensive study has been performed for the simple case of hydrogen and helium targets in collisions with various ions. Despite the fact that the simulations only account for classical mechanics effects, the calculated values are comparable to the experimental results for projectile velocities in the region corresponding to the maximum cross section. Shortcomings of the CTMC method for multi-electron target atoms are also discussed.
ANL, Argonne
GANIL, Caen
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
We have developed and tested an X-ray based Bunch Length Detector (XBLD) for application in ion accelerators. X-rays produced as a result of ion beam interactions with matter are used to generate photoelectrons. The photoelectrons are analyzed by an rf deflector synchronized with the master oscillator, similar to the BLDs based on secondary electrons. The expected time resolution is several picoseconds. The proposed XBLD is particularly useful for the measurement of cw heavy-ion beams passing through a stripper foil or film in a high-power driver accelerator. The results of the XBLD commissioning and beam bunch profile measurements at the ANL heavy-ion cw ATLAS accelerator will be presented.
GSI, Darmstadt
Laboratoire de Physique des Gaz et des Plasmas, Universite Paris-Sud, Orsay
IPCP, Chernogolovka, Moscow region
TU Darmstadt, Darmstadt
Universidad de Castilla-La Mancha, Ciudad Real
Studies of High Energy Density (HED) states in matter is one of the recently proposed important applications of intense particle beams. GSI Darmstadt is worldwide famous due to its unique accelerator facilities. Construction of the new accelerator FAIR, will enhance these capabilities many fold. During the past years, extensive theoretical work has been carried out to propose future HED physics experiments that could be carried out at FAIR. It is expected that the new heavy ion synchrotron, SIS100, will deliver a uranium beam with 1012 uranium ions that will be delivered in a single bunch, 50 – 100 ns long. Circular, elliptic and annular focal spots can be generated that will allow one to perform different type of HED physics experiments. This work has shown that using a special technique, named HIHEX, one may access those areas of the phase diagram that have never been accessed before. Using another experimental configuration, LAPLAS , it will be possible to generate physical conditions that are expected to exist in the interiors of the giant planets. Material properties under dynamic conditions can also be studied using a third experimental set up.
GSI, Darmstadt
In order to achieve the goals of the FAIR project, the heavy ion beam intensities have to be increased by two orders of magnitude. Space charge limits and significant beam loss in stripper stages disable a continuation of the present high charge state operation. However, in the energy range of SIS18 and SIS100, the chosen intermediate charge state for uranium 28+, is lower than the equilibrium charge state. Thus ionisation processes due to collisions with rest gas atoms become the main issue with respect to potential beam loss. Therefore, the SIS100 design concept is focused on the goal to minimization the beam-rest gas interaction and consequently the beam loss by charge change: SIS100 is the first synchrotron which has been optimised for the acceleration of intermediate charge state heavy ion operation. Ionisation beam loss, desorption processes and pressure stabilization were the driving issues for the chosen system layout and for several technological approaches. Beside focusing the SIS100 design on this specific issue an extended upgrade program is actually being realized to accommodate SIS18 for the intermediate charge state booster operation.
Nagaoka University of Technology, Nagaoka, Niigata
University of the Thai Chamber of Commerce, Bangkok
TIT, Yokohama
KEK, Ibaraki
The KEK digital accelerator (KEKDA), which is an injector-free induction synchrotron capable of accelerating any ions with their possible charge state, is under construction*. This machine is an interesting device as a driver to explore a Warm Dense Matter (WDM) state. The irradiation onto a target at a small focal spot (< a few mm) with a short pulse duration (< 100 nsec) is required to create an interesting WDM state. The target temperature based on an equation-of-state fitted from SESAME table data is estimated as a function of the focal spot size and the ion number per bunch. Final focusing of an ion beam bunch extracted from KEKDA is realized through a half mini-beta system. For this purpose, the beamline has been carefully designed. Beam parameters, such as Twiss parameter, and the guiding magnet parameters will be given together with the drawing of the beamline.
*T. Adachi et al., “Modification of the KEK PS-Booster as a Digital Accelerator”, in this conference.
PPPL, Princeton, New Jersey
Funding: Research supported by the U. S. Department of Energy.
This paper presents a survey of the present theoretical understanding based on advanced analytical and numerical studies of collective interactions and instabilities for intense one-component ion beams, and for intense ion beams propagating through background plasma. The topics include: discussion of the condition for quiescent beam propagation over long distances; the electrostatic Harris instability and the transverse electromagnetic Weibel instability in highly anisotropic, one-component ion beams; and the dipole-mode, electron-ion two-stream instability (electron cloud instability) driven by an unwanted component of background electrons. For an intense ion beam propagating through a charge-neutralizing background plasma, the topics include: the electrostatic electron-ion two-stream instability; the multispecies electromagnetic Weibel instability; and the effects of a velocity tilt on reducing two-stream instability growth rates. Operating regimes are identified where the possible deleterious effects of collective processes on beam quality are minimized.
PPPL, Princeton, New Jersey
LBNL, Berkeley, California
Funding: Research Supported by US Department of Energy.
Plasma are a source of unbound electrons for charge netralizing intense heavy ion beams to focus them to a small spot size and compress their axial length. To produce long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients have been developed. The source utilizes the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic material. High voltage (~8kV) is applied between the drift tube and the front surface of the ceramics. A BaTiO3 source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma in the 5x1010 cm-3 density range. The source has been integrated into the NDCX device for charge neutralization and beam compression experiments. Initial beam compression experiment yielded current compression ratios ~ 120. Recently, an additional 1 meter long source was fabricated to produce a 2 meter source for NDCX compression experiments. Present research is developing higher density sources to support beam compression experiments for high density physics applications.
JAEA, Ibaraki-ken
RIST, Ibaraki
NSCL, East Lansing, Michigan
Funding: The funding information for R.M. Ronningen is U.S. Department of Energy Grant Number DE-FG02-08ER41548.
The Particle and Heavy Ion Transport Code (PHITS)* has been typically used to predict radiation levels around high-energy (above 100 MeV/u) heavy-ion accelerator facilities. However, predictions of radiation levels around low-energy (around 10 MeV/u) heavy-ion facilities are also desirable, but the reliability of PHITS at low energies has not been investigated. In this work, neutron energy spectra from 10 MeV/u 12C and 16O ions incident on C and Cu targets have been calculated using the quantum molecular dynamics (QMD) model coupled to the generalized evaporation model (GEM) in PHITS. In particular, the influence of the “switching time”, defined as the time when the QMD calculation is stopped and the calculation switches to the GEM model, was studied. The calculated neutron energy spectra obtained using a value of 100 fm/c for the switching time agree well with the experimental data. We have also used PHITS to simulate an experimental study by Ohnesorge et al.**, by calculating neutron dose equivalent rates, for 3-16 MeV/u 12C, 16O and 20Ne beams incident on Fe, Ni and Cu targets. The calculated neutron dose equivalent rates agree well with the data.
*H. Iwase, K. Niita and T. Nakamura, J. Nucl. Sci. Technol. 39, 1142 (2002).
**W.F. Ohnesorge, H.M.Butler, C.B.Fulmer and S.W.Mosko, Health Physics 39, 633 (1980).
IMP, Lanzhou
CSR is a new ion cooler-storage-ring system in China IMP, it consists of a main ring (CSRm) and an experimental ring (CSRe). The two existing cyclotrons of the Heavy Ion Research Facility in Lanzhou (HIRFL) are used as its injector system. The heavy ion beams from the cyclotrons are injected first into CSRm for accumulation with e-cooling and acceleration, finally extracted fast to CSRe for internal-target experiments and mass measurements of radioactive ion beams (RIBs), or extracted slowly for external-target experiments or cancer therapy. In 2005 the CSR construction was completed and the commissioning finished in the past three years. It includes stripping injection (STI), electron-cooling with hollow electron beam, C-beam stacking with the combination of STI and e-cooling, wide energy-range acceleration from 7 MeV/u to {10}00 MeV/u with the RF harmonic-number changing, multiple multi-turn injection (MMI) and beam accumulation with MMI and e-cooling for heavy-ion beams of Ar, Kr and Xe, fast and slow extraction from CSRm, the commissioning of CSRe with two lattice modes, and a RIB mass-spectrometer test with the isochronous mode in CSRe by the time-of-flight method.
POSTECH, Pohang, Kyungbuk
Funding: Work supported by MEST and PAL.
Recently the Korean government successfully completed a large-scale facility, called the KSTAR, a fully superconducting tokamak after joining in the ITER project. It made renewed interests in large-scale scientific facilities to promote basic and applied research capabilities. The next projects include a space project and particle accelerators. The immediate one in accelerator program is the PLS-upgrade, and its budget is now in the congress for FY2009. The others are in the middle of consensus making process: a heavy ion accelerator for rare isotopes and a new synchrotron light source other than the PLS-upgrade and the ongoing proton linac program. This paper will give an overview of the status and prospects of major particle accelerator initiatives in Korea. The paper will also include descriptions of the significant contributions undertaken by Korea through collaborations with major international facilities using particle accelerators. Finally, the paper will outline how industry, government and universities in Korea are collaborating on particle accelerator R&D.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
RHIC BPM system average orbit was originally calculated by averaging positions of 10000 consecutive turns for a single selected bunch. Known perturbations in RHIC particle trajectories, with multiple frequencies around 10 Hz, contribute to observed average orbit fluctuations. In 2006, the number of turns for average orbit calculations was made programmable; this was used to explore averaging over single periods near 10 Hz. Although this has provided an average orbit signal quality improvement, an average over many periods would further improve the accuracy of the measured closed orbit. A new continuous average orbit calculation is currently under development and planned for use in the 2009 RHIC run. This paper will discuss the algorithm, performance with a simulated beam signal, and beam measurements.
BNL, Upton, Long Island, New York
A gas fluorescence beam profile monitor has been realized at the relativistic heavy ion collider (RHIC) using the polarized atomic hydrogen gas jet. RHIC proton beam profiles in the vertical plane are obtained as well as measurements of the width of the gas jet in the beam direction. For gold ion beams, the fluorescence cross section is sufficiently large so that profiles can be obtained from the residual gas alone, albeit with long light integration times and lower number of Au ions than protons. We estimate the fluorescence cross-section of 100 GeV protons and Au ions on hydrogen gas to be 6.6x10-21 cm2 ~1.7x10-16 cm2, respectively*. We calculate the beam emittance to provide an independent measurement of the RHIC beam. This optical beam diagnostic technique, utilizing the beam induced fluorescence from injected or residual gas, represents a step towards the realization of a simple and truly noninvasive beam monitor for high-energy particle beams together with a wall-current-monitor system and/or a low light level optical temporal measurement system, a 3-dimensional particle beam profile system can be envisioned providing routine diagnosis of high-energy particle beams.
*T. Tsang, et. al., Rev. Sci. Instrum. 79, 105103 (2008).
BNL, Upton, Long Island, New York
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
IAP, Frankfurt am Main
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A new 4 rod RFQ fabricated by IAP, Frankfurt, is being commissioned at Brookhaven National Laboratory. The RFQ will accelerate intense heavy ion beams provided by an Electron Beam Ion Source (EBIS) up to 300 keV/u. The RFQ will accelerate a range of Q/M from 1 to 1/6, and the accelerated beam will be finally delivered to RHIC and NSRL. The first beam test is planned to use beams from the BNL Test EBIS. The detailed test results will be presented.
GSI, Darmstadt
The GSI UNILAC serving as a high duty factor heavy ion linac is in operation since nearly 35 years. An upgrade program dedicated to FAIR will be finished until 2011. For the FAIR project the synchrotron SIS 18 has to be filled up to the space charge limit. After re-commissioning of the UNILAC the replacement of the main DTL is foreseen. A new 4 MV/m 108 MHz IH-LINAC provides a high intensity 5 MeV/u U4+-beam. The existing gas stripper section is reused to perform a beam intensity of 24 emA in charge state 42+. The existing UNLAC-tunnel may house a high efficient linac structure. A superconducting or normal conducting 324 MHz-CH-linac (crossbar H-structure) is under consideration as well as rf-resonators of half wave or quarter wave type. The new high energy linac should be able to boost the beam energy up to 30 MeV/u. A further upgrade option is a second 100 m-linac (324 MHz) to enhance the beam energy to up to 100 MeV/u (U41+), sufficient to feed the FAIR 100 Tm synchrotron in direct line. The paper will report on the ongoing conceptual layout of a new UNILAC-concept.