| Paper | Title | Page |
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| MOPPC034 | Use of Helical Transport Channels for Bunch Recombination | 205 |
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| Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed. | ||
| MOPPD043 | Novel Muon Beam Facilities for Project X at Fermilab | 457 |
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| Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study. | ||
| MOPPD044 | Optimization of the Target Subsystem for the New g-2 Experiment | 460 |
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| A precision measurement of the muon anomalous magnetic moment, aμ = (g-2)/2, was previously performed at BNL with a result of 2.2 - 2.7 standard deviations above the Standard Model (SM) theoretical calculations. The same experimental apparatus is being planned to run in the new Muon Campus at Fermilab, where the muon beam is expected to have less pion contamination and the extended dataset may provide a possible 7.5σ deviation from the SM, creating a sensitive and complementary benchmark for proposed SM extensions. We report here on a preliminary study of the target subsystem where the apparatus is optimized for pions that have favorable phase space to create polarized daughter muons around the magic momentum of 3.094 GeV/c, which is needed by the downstream g 2 muon ring. | ||
| TUPPD005 | Design Concept for Nu-STORM: an Initial “Very Low-Energy Neutrino Factory” | 1413 |
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Funding: US DOE under contract DE-AC02-07CH11359 We present a design concept for a Nu-source from a STORage ring for Muons - NuSTORM. In this initial design a high-intensity proton beam produces ~5 GeV pions that provide muons that are captured using “stochastic injection” within a ~3.6 GeV racetrack storage ring. In “stochastic injection”, the ~53 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the ~2 GeV/c ring momentum acceptance and are stored for the muon lifetime of ~1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams that can be used for precision measurements of neutrino interactions, and neutrino oscillations or disappearance at L/E=~1 m/MeV. The facility is described and variations are discussed. |
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| TUPPD012 | Complete Muon Cooling Channel Design and Simulations | 1431 |
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| Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another. | ||
| TUPPD013 | Bunch Coalescing in a Helical Channel | 1434 |
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Funding: Supported in part by SBIR Grant 4725 · 09SC02739. A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV. |
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| TUPPD033 | Conceptual Design of a Positron-annihilation System for Generation of Quasi-monochromatic Gamma Rays | 1476 |
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| A conceptual design is presented for a system consisting of the following: an electron accelerator and production target to produce positrons, a dipole magnet and wedge to compress the positron momenta to be nearly monochromatic, a magnetic transport system to focus and direct the positrons to a converter, and a converter in which the positrons annihilate in flight to produce quasi-monochromatic gamma rays. The system represented is designed to produce ~10 MeV gammas, but it can also be designed for other energies. | ||
| TUPPD043 | Resonant Reaction with a Superintense Circulating Beam | 1497 |
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| A system for efficient generation of resonance reaction in the interaction of the circulating ion beam with a thin internal target is considered. Features of this system are high intense space charge compensated circulating ion beam with an intensity greater then a space charge limit in a near integrable nonlinear focusing system. Ionization energy loss is compensated by inductive electric field. Multiple scattering and energy straggling are compensated by electron cooling with a tabular electron beam. In this method it is possible to compensate an energy loss of circulating particles after crossing the target and have a crossing of resonant energy in every passing of target. For sharp resonance reactions and monoenergetic beams a thin target method can increase greatly the energy efficiency. | ||
| TUPPD044 | Conceptual Gas Jet as a Stripping Target for Charge Exchange Injection | 1500 |
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| Stripping targets for charge exchange injection now uses thin carbon or Al2O3 foils. During long time injection for high intense beam accumulation by low current injection a foil life time can be compromised by overheating and alternative stripping targets need be developed. A pulsed supersonic gas jet was used as a stripping target in first realization of charge exchange injection with H− ion energy 1.5 MeV and stationary gas jets are used as internal targets in experiments with super high vacuum. A stripper target thickness is proportional to the injection energy and for energy 1GeV should be ~0.3 mg/cm2 of carbon. The pulsed gas target with such thickness acceptable for long time charge exchange injection can be produced with using of heavy hydrocarbon molecules used in the diffusion or booster vacuum pumps. Formation of the pulsed gas jet stripping targets will be considered. | ||
| TUPPD045 | Efficient Plasma Generation by Positive Circulating Beams | 1503 |
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| Performances of high brightness circulating beams are affected by development of strong “electron-proton” (e-p) instabilities connected with generation of an electron cloud (EC). For suppression of the EC generation it is proposed a coating of vacuum chambers by compounds with low secondary electron emission, which is very complex and expensive for large systems like LHC or RHIC. Threshold beam intensity for EC generation can be increased during the vacuum chamber bombarding by plasma particles generating by EC. Vacuum chamber processing (scrubbing) by EC is conducted by bunched beam with a highest possible intensity and with shortest gaps between bunches. Highly efficient plasma generation can be produced in the coasting circulating beam of positive particles with relative low intensity and energy. With the coasting positive beam the plasma particles are generating by low energy electrons trapped by a positive beam space charge. Dynamics of electrons and ions generation will be estimated and simulated. The rate of plasma generation and surface scrubbing can be increase by decrease of pumping and injection of selected gases. | ||
| THPPR062 | Handling GEM*STER Volatile Radioactive Fission Products | 4115 |
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| A next-generation advanced technology of nuclear power has been developed for many years. One of the promising future reactor designs with accelerator-produced neutrons is GEM*STAR (Green Energy Multiplier*Subcritical Technology for Alternative Reactors) developed by Accelerator Driven Neutron Application (ADNA), which is a subcritical thermal-spectrum reactor operating with molten salt fuel in a graphite matrix. GEM*STAR is able to use natural uranium as well as unreprocessed spent fuel from light-water reactors (LWR), generating as much electricity as the LWR had generated from the same fuel. Since the advanced design of GEM*STAR is quite different from LWR that uses solid nuclear fuel loaded in the Zircaloy, it requires emission control for volatiles emitted from the molten salt fuel, like as radioactive iodine and cesium. The volatiles caught in the helium gas circulating around the core reactor will be trapped in the cryogenic bottles. Numerical simulations to estimate the amount of fission products were performed for the design of confinement of the volatiles. The result of simulation with spent nuclear fuel from LWR is presented. | ||