42 research outputs found
The Design of the Orthogonal Box Cavity
The muon collider and/or the neutrino factory require large accelerating electric field gradients immersed in large (3 to 6 T) solenoidal magnetic fields for ionization cooling of muon beams. Our original vacuum breakdown study demonstrated a loss of achievable peak accelerating gradient in solenoidal magnetic fields by a factor 2 or greater. The Muon Collaboration has developed a theory of a method to suppress high electric field breakdown in vacuum cavities needed for a Muon collider or neutrino factory. It has been shown in our studies and by others that high gradient electric field emitted electrons (dark current) are the primary cause of breakdown. A DC magnetic field orthogonal to the RF electric accelerating field prevents dark current high field emitted electrons from traveling across the accelerating gap and then will prevent breakdown. We have decided to test this theory by building a special cavity in the shape of vacuum box. Figure 1 is a simplified view of the cavity design. The design is based on an 805 MHz WR975 waveguide cavity resonating in the TE{sub 101} mode. For the TE{sub 101} mode the resonant frequency f{sub 0} is given by the relationship f{sub 0} = c[(I/a){sup 2} + (m/b){sup 2} + (n/d){sup 2}]{sup 0.5}/2 where a and d are the lengths of the base sides and b is the height of the box in MKS units and c is the velocity of light
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201 MHz Cavity R&D for MUCOOL and MICE
We describe the design, fabrication, analysis and preliminary testing of the prototype 201 MHz copper cavity for a muon ionization cooling channel. Cavity applications include the Muon Ionization Cooling Experiment (MICE) as well as cooling channels for a neutrino factory or a muon collider. This cavity was developed by the US muon cooling (MUCOOL) collaboration and is being tested in the MUCOOL Test Area (MTA) at Fermilab. To achieve a high accelerating gradient, the cavity beam irises are terminated by a pair of curved, thin beryllium windows. Several fabrication methods developed for the cavity and windows are novel and offer significant cost savings as compared to conventional construction methods. The cavity's thermal and structural performances are simulated with an FEA model. Preliminary high power RF commissioning results will be presented
Status of Muon Collider Research and Development and Future Plans
The status of the research on muon colliders is discussed and plans are
outlined for future theoretical and experimental studies. Besides continued
work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy
collider, many studies are now concentrating on a machine near 0.1 TeV (CoM)
that could be a factory for the s-channel production of Higgs particles. We
discuss the research on the various components in such muon colliders, starting
from the proton accelerator needed to generate pions from a heavy-Z target and
proceeding through the phase rotation and decay ()
channel, muon cooling, acceleration, storage in a collider ring and the
collider detector. We also present theoretical and experimental R & D plans for
the next several years that should lead to a better understanding of the design
and feasibility issues for all of the components. This report is an update of
the progress on the R & D since the Feasibility Study of Muon Colliders
presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A.
Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics
(Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics,
Accelerators and Beam
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The Design of the Orthogonal Box Cavity
The muon collider and/or the neutrino factory require large accelerating electric field gradients immersed in large (3 to 6 T) solenoidal magnetic fields for ionization cooling of muon beams. Our original vacuum breakdown study demonstrated a loss of achievable peak accelerating gradient in solenoidal magnetic fields by a factor 2 or greater. The Muon Collaboration has developed a theory of a method to suppress high electric field breakdown in vacuum cavities needed for a Muon collider or neutrino factory. It has been shown in our studies and by others that high gradient electric field emitted electrons (dark current) are the primary cause of breakdown. A DC magnetic field orthogonal to the RF electric accelerating field prevents dark current high field emitted electrons from traveling across the accelerating gap and then will prevent breakdown. We have decided to test this theory by building a special cavity in the shape of vacuum box. Figure 1 is a simplified view of the cavity design. The design is based on an 805 MHz WR975 waveguide cavity resonating in the TE{sub 101} mode. For the TE{sub 101} mode the resonant frequency f{sub 0} is given by the relationship f{sub 0} = c[(I/a){sup 2} + (m/b){sup 2} + (n/d){sup 2}]{sup 0.5}/2 where a and d are the lengths of the base sides and b is the height of the box in MKS units and c is the velocity of light
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The determination of the 805 MHz side coupled cavity dimensions for the Fermilab Linac upgrade
In order to achieve the proper frequencies and coupling in Side Coupled Accelerator Structures, it is often necessary to model the cavities. In order to reduce the number of modeling steps and hence reduce machine shop time and cost, we have drawn heavily upon previous LAMPF experience and present day numerical calculation programs. Using a few aluminum cavity models at selected machine energies, we have been able to predict the frequency and coupling of our structures with good accuracy. This paper will describe the steps used to determine the cavity dimensions that meet our structure requirements. 6 refs., 6 figs
Ascorbate enhances iron uptake into intestinal cells through formation of a FeCl3-ascorbate complex
It has been well documented that ascorbate enhances iron uptake, with a proposed
mechanism based on reduction to the more absorbable ferrous form. We have
performed a study on the effects of ascorbate on ferric iron uptake in the human
epithelial Caco-2 cell-line. Ascorbate increased uptake in a concentration-
dependent manner with a significant difference between iron uptake and
reduction. Uptake kinetics are characteristic of a non-essential activator and
the formation of an Fe3+-ascorbate complex. This investigation provides evidence
that ascorbate enhances the apical uptake of ferric iron into Caco-2 cells
through the formation of a Fe3+-ascorbate complex. (C) 2010 Elsevier Ltd. All
rights reserved
Untersuchungen über die DNA-Synthese peripherer Lymphozyten bei progredient chronischer Polyarthritis
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MANX, A 6-D Muon Cooling Demonstration Experiment
Most ionization cooling schemes now under consideration are based on using many large flasks of liquid hydrogen energy absorber. One important example is the proposed Muon Ionization Cooling Experiment (MICE), which has recently been approved to run at the Rutherford Appleton Laboratory (RAL). In the work reported here, a potential muon cooling demonstration experiment based on a continuous liquid energy absorber in a helical cooling channel (HCC) is discussed. The original HCC used a gaseous energy absorber for the engineering advantage of combining the energy absorption and RF energy regeneration in hydrogen-filled RF cavities. In the Muon And Neutrino eXperiment (MANX) that is proposed here, a liquid-filled HCC is used without RF energy regeneration to achieve the largest possible cooling rate in six dimensions. In this case, the magnetic fields of the HCC must diminish as the muons lose momentum as they pass through the liquid energy absorber. The length of the MANX device is determined by the maximum momentum of the muon test beam and the maximum practical field that can be sustained at the magnet coils. We have studied a 3 meter-long HCC example that could be inserted between the MICE spectrometers at RAL