Experimental Results from the Small Isochronous Ring

EXS, 1975

A separated sector cyclotron post-accelerator , is proposed for the Oak Ridge Heavy Ion Laboratory. The SSC accepts beams from either ORIC or the 25 MV tandem electrostatic accelerator and extends the maximum particle energy to 75 MeV/u for A less than 40 and to at least 10 MeV/u for A greater than 40. The SSC has a field-radius product of 2540 kG-cm, a 4-sector configuration, and azimuthal pole width of 52°. RF acceleration of up to 1 MV per turn is obtained with two resonators in opposite valleys. An RF tuning range of 6 to 14 MHz accommodates acceleration on harmonics 2 through 11. Concentric second harmonic resonators are provided for optimizing phase acceptance.

Conference Record of the 1991 IEEE Particle Accelerator Conference, 1991

colliders are considered as one approach to an asymmetric B-factory. The beam-beam effect in a superconducting linac is different from the beam-beam effect in a storage ring or linear collider[tl.

Physics of Fluids, 1983

2007 IEEE Particle Accelerator Conference (PAC), 2007

J-PARC Main Ring (MR) should provide the beam power up to 0.8MW at the maximum energy of 50GeV. The total beam intensity in this case should be 3.3e14. According to the basic machine parameters the harmonic number of MR is 9, the number of bunches around the ring is 8. The power of the bunch is about 6 kW at the injection energy of 3GeV. At the beginning of the high power operation we expected to get about 2 kW per bunch. Limitation the uncontrolled particle losses for the high-intensity beam accelerators is one of the most serious issue. The MR collimator should cut the tail particles during the injection process and at the beginning of the acceleration. Acceptable power of the lost beam at the scraper is about 500W, which is about 1% from the beam power at the injection energy. In frame of this report we analyze the combined effect of the low-energy space charge and the 'lattice' resonances, caused by the machine imperfection for different machine operation scenario including the collimation system of the 3-50BT beam line between RCS and MR and the MR collimator system. The measured field data for main magnets of MR has been used for this study. The budget of the particle losses during the injection and acceleration processes for the MR operation have been established.

AIP Conference Proceedings, 2006

Electron Ring (UMER) is built as a low-cost testbed for intense beam physics for benefit of larger ion accelerators. The beam intensity is designed to be variable, spanning the entire range from low current operation to highly space-charge-dominated transport. The ring has been closed and multi-turn commissioning has begun. One of the biggest challenges of multi-turn operation of UMER is correctly operating the Y-shaped injection/recirculation section, which is specially designed for UMER multi-turn operation. It is a challenge because the system requires several quadrupoles and dipoles in a very stringent space, resulting in mechanical, electrical, and beam control complexities. Also, the earth's magnetic field and the image charge effects have to be investigated because they are strong enough to impact the beam centroid motion. This thesis presents both simulation and experimental study of the beam centroid motion in the injection region to address above issues.

Proceedings Particle Accelerator Conference

In this paper, we discuss ion effects relevant to future storage rings and linear colliders. We ®rst review the conventional ion effects observed in present storage rings and then discuss how these effects will differ in the next generation of rings and linacs. These future accelerators operate in a new regime because of the high current long bunch trains and the very small transverse beam emittances. Usually, storage rings are designed with ion clearing gaps to prevent ion trapping between bunch trains or beam revolutions. Regardless, ions generated within a single bunch train can have signi®cant effects. The same is true in transport lines and linacs, where typical vacuum pressures are relatively high. Amongst other effects, we address the tune spreads due to the ions and the resulting ®lamentation which can severely limit emittance correction techniques in future linear colliders, the bunch-to-bunch coupling due to the ions which can cause a multi-bunch instability with fast growth rates, and the betatron coupling and beam halo creation which limit the vertical emittance and beam lifetimes.

Space-charge-induced emittance growth and halo generation could lead to unacceptably high beam loss in high intensity rings, such as the SNS [1]. In such accelerators, uncontrolled losses to the walls as small as one part in 10 4 would lead to activation, making maintenance difficult. For this reason it is essential to understand the effects of space charge on beam dynamics, and halo generation in particular, in high intensity rings. We have undertaken the study of space charge dynamics in high intensity rings using a particle tracking approach, with self-consistent evaluation of the space charge forces through a particle-in-cell model. Because of the stringent loss requirements, it is necessary to thoroughly guarantee the reliability of these calculations to high precision through comparison with experiments and through convergence studies. In this paper we present the results of convergence studies in the parameters of the model, namely, the number of macroparticles, the resolutio...

1998

The Heavy Ion Fusion Group at Lawrence Livermore National Laboratory has been developing the world's first ion induction accelerator. This machine has recently been extended to 90 degress, or 10 half-lattice periods(HLP) with full beam transport. As part of this extension, two new diagnostic systems have been fully enabled, the Capacitive Beam Probes(C-probes) and the Gated Beam Imager(GBI). The C-probes

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268), 2001

Results are presented of the first experiments with a 10 keV, 100 mA beam in the matching section for UMER. The section, about 1.5 m long, consists of one short solenoid, six printed-circuit (PC) quadrupoles, a bend PC dipole, a number of steering dipoles, and two sets of Helmholtz coils for balancing the Earth's field. The 2 RMS beam radius as a function of axial distance in the straight part of the beam line is obtained from fluorescent screen pictures. The results are compared with calculations using the K-V envelope equations. The importance of an accurate determination of the initial conditions, i.e. beam envelope size and slope at the entrance plane, as well as the emittance, is emphasized. Furthermore, the role of different types of errors, specially misalignment and quadrupole rotations is discussed.

2021

The Future Circular Collider study program comprises several machine concepts for the future of high-energy particle physics. Among them there is a twin-ring e⁻e⁺ collider capable to run at beam energies between 45.6 and 182.5 GeV, i.e. the energies corresponding to the resonances of the Z, W, H bosons and the top quark. The conceptual design of the two 100-km rings has advanced to what is believed to be a working solution, i.e. capability to deal with low-energy (45.6 GeV) high-current (1390 mA) version as well as the high-energy (182.5 GeV) low-current (5.4 mA) one, with intermediate energy and current steps for the other 2 resonances. The limit for all of the versions is given by the 50 MW/beam allotted to the synchrotron radiation (SR) losses. The paper will outline the main beam/machine parameters, the vacuum requirements, and the choices made concerning the vacuum chamber geometry, material, surface treatments, pumping system, and the related pressure profiles. The location of...

2006

Even though CERN's Large Hadron Collider (LHC) is mainly conceived to accelerate protons, a heavy ion physics program is also foreseen. In order to reach the luminosity required for LHC, the ion accelerator chain needed to be upgraded, and a central part is the new Low Energy Ion Ring (LEIR). Its role is to transform a series of long, low-intensity ion pulses from Linac-3 into short, high-density pulses which will be further accelerated in the PS and SPS rings before injection into LHC. To do so the injected pulses are stacked and phase-space cooled using electron cooling before acceleration to the ejection energy of 72 MeV/u. This note describes the different types of instruments used in the LEIR ring and transfer lines and reports on the first results obtained with O4+ and Pb54+ beams.

IEEE Transactions on Nuclear Science, 1985

DoRtdra the optics monnuriiinciil.il described elsewhere, maclilno experiments ware done at Ilia SLC damping ring to determine aome of Its parameters. The synchrotron radi ation energy lam which glve» the damping rates was meemired by observing the RF-vollage dependence of tire syn chronous phase angle. Tito omittance was obtained from the synchrotron light monitor, scraper measurements and by ex tracting the beam through a doublet and measuring its site for different qnadrunole settings. Current dependent effects such as parasitic mode losses, head tail instabilities, synchrotron and betatron frequency shifts were measured to estimate the impedance. llF-cavlly beam loading and Its compensation were nlao studied and ion collection was investigated. All re sults agree reasonably well with expectations and indicate no limitations to the design performance.

Nuclear Technology and Radiation Protection, 2012

Short-lived exotic nuclei can be produced and separated with the high-energy nuclear beam facility called fragment separator at the Centre for Heavy Ion Research. These nuclides can be injected and stored in the storage ring called experimental storage ring. The lower lifetime limit of the presently existing methods for mass measurements on these nuclides at the experimental storage ring is about a few seconds. We have developed and investigated an isochronous operational mode of the future collector ring, that makes mass measurements feasible for nuclides with lifetimes down to a few microseconds. A mass resolving power of about 150 000 is expected.

Conversion of the isochronous cyclotron U-120M into H−, D− accelerator has extended significantly its utilization. A prompt and reliable setup of cyclotron regimes and tuning of the beam parameters according to a wide range of specific requirements is desirable. For this purpose, a new software has been developed and continually upgraded in last few years. A set of computer codes simulates a detailed numerical analysis of the accelerated beam parameters and trajectories for both positive and negative regimes. The software package is also used for optimization of the beam parameters for extraction by the stripping method. Our experience shows that only the setup of the main coil current and stripping foil position suggested by the code is to be slightly corrected in order to extract the beam to the target position. Several examples demonstrate a good agreement of calculated and monitored beam parameters and its behaviour.

2012

The slow cycling main ring synchrotron (MR) is located the furthest downstream in the J-PARC accelerator cascade. It became available for user operation in 2009 and provides high-intensity 30GeV proton beams for various experiments on particle and nuclear physics. The MR has two beam extraction systems: a fast extraction system for beam delivery to the neutrino beam line of the Tokai-to-Kamioka (T2K) experiment and a slow extraction system for beam delivery to the hadron experimental hall. After a nine-month beam shutdown during the recovery from the Great East Japan Earthquake, the J-PARC facility resumed beam operation in December 2011. The MR delivers a 160–200 kW beam to the T2K experiment and a 3.5–6 kW beam to users