Paper | Title | Page |
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TUPAS016 | Collimation System Design for Beam Loss Localization with Slipstacking Injection in the Fermilab Main Injector | 1688 |
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Results of modeling with the STRUCT and MARS15 codes of beam loss localization and related radiation effects are presented for the slipstacking injection to the Fermilab Main Injector. Simulations of proton beam loss are done using multi-turn tracking with realistic accelerator apertures, nonlinear fields in the accelerator magnets and time function of the RF manipulations to explain the results of beam loss measurements. The collimation system consists of one primary and four secondary collimators. It intercepts a beam power of 1.6 kW at a total scraping rate of 5%, with a beam loss rate in the ring outside the collimation region of 1 W/m or less. Based on thorough energy deposition and radiation modeling, a corresponding collimator design was developed that satisfies all the radiation and engineering constraints. | ||
TUPAS040 | Momentum Spread Reduction at Beam Extraction from the Fermilab Booster at Slipstacking Injection to the Main Injector | 1733 |
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In order to reduce the momentum spread of the beam at extraction from the Booster to the Main Injector with slip stacking injection, the bunch rotation at the end of the cycle is applied. However, the fast RF voltage reduction often causes beam loading issues to Booster RF cavities, and the reliability of extracted beam becomes a problem. An alternative solution is investigated - modulating the RF voltage with twice of the synchrotron frequency introduces bunch length oscillation, and the beam is extracted at the time when the bunch length reaches maximum and the momentum spread becomes minimal. | ||
TUPAS041 | Injection Parameters Optimization for the Fermilab Booster | 1736 |
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The maximal capacitance for the Booster to deliver the 8-GeV beam to downstream accelerators is limited by the beam loss. Most of losses happen at injection due to space charge effect being the strongest at the injection energy. Optimizing the RF voltage ramp in the presence of the space charge effect to capture more beam and simultaneously keep small beam emittance has been numerically investigated using 3-D STRUCT code. The results of simulations agree well with the measurements in the machine. Possibilities, such as beam painting and using the second rf harmonic at injection, for further reductions of beam loss in order to reach the maximum beam intensity delivered from the Booster have been investigated. | ||
TUPAS042 | Transition Crossing Simulation at the Fermilab Booster | 1739 |
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The demand in high intensity and low emittance of the beam extracted from the Booster requires a better control over the momentum spread growth and bunch length shortening at transition, in order to prevent beam loss and coupled bunch instability. Since the transition crossing involves both longitudinal and transverse dynamics, the recently modified 3-D STRUCT code provides an opportunity to numerically investigate different transition schemes in the machine environment, and apply the results of simulation to minimize the beam loss and emittance growth operationally. | ||
THPMN100 | Suppression of Muon Backgrounds Generated in the ILC Beam Delivery System | 2945 |
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Particle fluxes generated from the interactions of beam halo with the collimators in the ILC Beam Delivery System (BDS) can exceed tolerable levels for the collider detectors and create hostile radiation environment in the interaction region. Thorough analysis of the BDS model, beam loss patterns, driving geometry factors and physics processes along with verification of the simulation codes were performed for the current ILC BDS layout with 250-GeV electron and positron beams crossing at 14 mrad with a push-pull detector option. Muon flux reduction by distributed toroids (doughnut-type spoilers) in comparison with magnetic iron walls filling the BDS tunnel are calculated and analysed in great detail. Shielding conditions which allow occupancy of the interaction region while the full power beam is on the linac tuneup dump are also studied. | ||
WEOCAB01 | Design of the Beam Delivery System for the International Linear Collider | 1985 |
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The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design. | ||
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THPAN105 | Effects of Space Charge and Magnet Nonlinearities on Beam Dynamics in the Fermilab Booster | 3474 |
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Funding: Work supported by the Universities Research Assoc., Inc., under contract DE-AC02-76CH03000 with the U. S. Dept. of Energy Presently the Fermilab Booster can accomodate about half the maximum proton beam intensity which the Linac can deliver. One of the limitations is related to large vertical tuneshift produced by space-charge forces at injection energy. In the present report we study the nonlinear beam dynamics in the presence of space charge and magnet imperfections and analyze the possibility of space charge compensation with electron lenses. |