Fermilab, Batavia, Illinois
Understanding the behavior of high-intensity beams in the Fermilab Main Injector is crucial for the future physics program at the lab. Simulations of the Main Injector including collective effects are a crucial part of this understanding. We are building up a set of integrated simulations of collective effects using the Synergia accelerator simulation framework. As a step in this work we present simulations of space-charge effects combined with impedance effect in the Main Injector.
Fermilab, Batavia, Illinois
Obit Response Matrix (ORM) Fit method has been successfully used to calibrate linear optics at Recycler Ring at Fermilab. The linear model of the Recycler optics ring has been significantly improved. Based on the build-up model, lattice measurement of the Recycler ring has been done several times, each after some magnets move and the tunes change. Large beta-wave(~20%) has been found in horizontal plane after the working point was moved from (0.424,0.434) to (0.456, 0.467) for the reason of lowering the beam instabilities. The source of the beta-wave, and the correction will be presented in this paper. In addition, we found an easy way to extend the tuning range in the recycler lattice. A new application program for adjusting the tunes operationally was introduced and the measured results will be presented.
IUCF, Bloomington, Indiana
ORNL, Oak Ridge, Tennessee
SLAC, Menlo Park, California
Recently, discrepancies between model-based and observed linear optics, such as the tune and the closed orbit, have been observed in the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Accurate accelerator modeling is very important for machine control during the ongoing power ramp up. The Orbit Response Matrix (ORM) method is applied here to find and correct errors in the linear optics of the SNS ring. With the closed orbit data (4472 data points), we are able to calibrate the strength of the steering magnets, the BPM gain factors, and 6 quadrupole power supplies. Current results and remaining challenges will be presented and discussed.
BNL, Upton, Long Island, New York
NSCL, East Lansing, Michigan
CERN, Geneva
Isochronous cyclotrons, rings for precise nuclear mass spectrometry, and some isochronous-optics light sources with extremely short bunches are operated or proposed to be operated in the isochronous or almost isochronous regime. Also, many hadron synchrotrons run in the isochronous regime for a short period of time each acceleration cycle during transition crossing. The longitudinal motion is “frozen” in the isochronous regime that leads to accumulation of the integral of the longitudinal space charge force. In low-gamma hadron machines, this can cause a fast growth of the beam energy spread even at modest beam intensities. In this paper, I discuss specifics of space charge in the isochronous regime and present experimental results obtained in the Small Isochronous Ring, developed at Michigan State University specifically for studies of space charge in the isochronous regime.
ANL, Argonne, Illinois
Matrix-based beam optics codes such as TRACE-3D are often used for small scale optimizations such as beam matching which involves a limited number of parameters. The limitation of such codes is further amplified for high-intensity and multiple charge state beams as their predictions start to deviate from the more realistic 3D particle tracking codes. For these reasons we have started developing large scale optimization tools for beam tracking codes. The large scale nature comes first from the possibility of optimizing a large number of parameters and second from the minimum number of particles to track especially for space charge dominated beams. The ultimate goal of these developments is not only to optimize the design of an accelerator but also to be able to use a beam dynamics code to operate it once built. A selected set of optimization options will be presented and discussed along with specific applications. We'll also emphasize the need for parallel computing to speed-up the optimization process.
CERN, Geneva
UPC, Barcelona
A 50 GeV proton synchrotron machine to replace the current PS (PS2) is foreseen in the framework of the LHC complex upgrade. For high intensity beams, losses constitute a great concern in terms of hands-on maintenance and radioactivation. To minimize the uncontrolled losses all around the ring a collimation system is required. Lattice design and collimation studies are carried out in parallel in order to optimize the cleaning efficiency. To this end the robustness of the system is tested for different lattice configurations against orbit errors and optics distortions.
CERN, Geneva
The PS2, foreseen as a replacement of the CERN PS, is designed as a racetrack shaped machine with two long straight sections (LSS) for injection/extraction and RF, respectively. Two injection and three extraction systems are required, and in the present study are designed to fit in either a six-cell FODO or a seven-cell DOFO insertion, with a central triplet in order to fit the complete H- injection in one long drift. This study covers the optimisation of the LSS optics and the arrangement and characteristics of the various insertion elements. The main focus lies on the H- injection embedded in the triplet cell with the design of the chicane and painting bump according to the limits of Lorentz-stripping, excited H0 behaviour and the focusing effects of the chicane dipoles on the overall optics.
CERN, Geneva
The Large Hadron Collider (LHC) will collide two protons beam with an energy of 7 TeV each. The stored energy and intensity exceeds the quench level of the superconducting magnets and the damage level of the machine components by far. Therefore a robust and reliable collimation system is required which controls the losses to the superconducting magnets below the quench limit and to protect the accelerator components from damage in the event of beam loss. The layout and design of the LHC collimation system is presented and the expected system performance is shown. The calculated losses around the ring were provided as input for energy deposition studies in the cleaning insertions itself but also close to experimental insertions. In addition the results from studies on proton losses originating from p-p interaction in the experiments are shown.
CERN, Geneva
BNL, Upton, Long Island, New York
In view of the CERN Proton Synchrotron replacement with a new ring (PS2), a detailed optics design is undertaken following several options, which cross or avoid transition. The different lattices are compared with respect to their linear optics flexibility, acceptance and chromatic properties. The effect of magnet misalignments in the beam orbit and linear optics functions are reviewed and correction schemes are proposed. Finally, the different lattice options are compared with respect to single particle non-linear dynamics.