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We have investigated experimentally the propagation of relativistic electron beam through an array of parallel conducting wires. Theory and particle simulation predict such an array will provide both charge and current neutralizat...
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We have investigated experimentally the propagation of relativistic electron beam through an array of parallel conducting wires. Theory and particle simulation predict such an array will provide both charge and current neutralization, allowing beam transport above the drift tube limit. We injected a 60 ns, 17kA (120 A/cm(sup 2)) pulse of 1.4 MeV electrons into an array of 1 m long wires spaced 1 cm apart, filling a hexagon 15 cm across. Arrays have been tested with 12 mil diameter copper wire, 3 mil stainless steel wire, and 12 mil copper wires terminating on an insulated, segmented beam dump. (dot B) probes and streak camera data show that 67% of the current is transported in the case of the stainless steel array. The copper wire array transported electrons for 20 ns only. The beam is injected with a 250 mrad divergence, and the transported beam has a divergence of less than 100 mrad. Follow-up experiments are to use thinner wires to improve the propagation and divergence of the beam. 3 refs., 9 figs., 1 tab.
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The fundamentals of ion optics are presented, beginning with the basic non-relativistic equations of motion, and the conditions under which the paraxial equations hold. The relativistically correct equations are then presented. Th...
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The fundamentals of ion optics are presented, beginning with the basic non-relativistic equations of motion, and the conditions under which the paraxial equations hold. The relativistically correct equations are then presented. The basic focussing properties of dipoles and quadrupoles are described as well as the operation of the quadrupole doublet and triplet. The matrix formulation of optics is developed and used to derive a number of basic results such as imaging relations, principal planes, dispersion and achromatism. The concepts of emittance, acceptance, brightness and phase space are introduced and illustrated by examples. A waist in phase space is defined, and its relationship to a focus is discussed. Both the 'Sigma matrix and Twiss formulations' for phase-space transformations are presented and their inter-relationship shown. Liouville's Theorem is also discussed along with conditions for its validity. Examples of the action of a lens and a drift space on the beam phase space are given to illustrate the power of these concepts and develop some familiarity with them on the part of the reader. (Atomindex citation 16:042312)
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During the past years, significant progress has been made in understanding the beam transverse emittance blow-up and its preservation. However, it is difficult to explain what was observed in an existing machine or to predict what...
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During the past years, significant progress has been made in understanding the beam transverse emittance blow-up and its preservation. However, it is difficult to explain what was observed in an existing machine or to predict what will happen in a machine under design. There are a number of such examples given in this report.
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Three-dimensional (3-d) radiation transport simulations have been performed todefine the shielding requirements of a generic neutron beam line and generic T(sub 0), E(sub 0) and bandwidth choppers for the Spallation Neutron Source...
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Three-dimensional (3-d) radiation transport simulations have been performed todefine the shielding requirements of a generic neutron beam line and generic T(sub 0), E(sub 0) and bandwidth choppers for the Spallation Neutron Source (SNS). In these analyses, the beam line and chopper models were located between 5 m and 10 m from the moderator face, at their closest likely positions relative to the moderator. From these calculations the maximum required shielding is determined for each chopper.
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We consider a technique to determine the initial beam conditions of the DARHT II accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a funct...
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We consider a technique to determine the initial beam conditions of the DARHT II accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit beam radius, tilt, and emittance. We find that systematic errors cancel and so are not a problem in unfolding the initial beam conditions. Random uncorrelated shot to shot errors can be managed by one of three strategies: (1) make the transport system optically de-magnifying; (2) average over many individual shots; or (3) make the random uncorrelated shot to shot errors sufficiently small. The high power of the DARHT II beam requires that the beam transport system leading to a radius measuring apparatus be optically magnifying. This means that the shot to shot random errors must either be made small less than about 1%, or that we average each of the three beam radius determinations over many individual shots.
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We analyze the stability issues of the 3 TeV low-field collider. Some relevant properties of the collider are listed in Table 1. In the table, the rms bunch length of (sigma)(sub l)=0.50 m and bunch area of A=1.50 eV-s at injectio...
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We analyze the stability issues of the 3 TeV low-field collider. Some relevant properties of the collider are listed in Table 1. In the table, the rms bunch length of (sigma)(sub l)=0.50 m and bunch area of A=1.50 eV-s at injection are extraction values from the Main Injector. At extraction of this 3 TeV ring, we assume the bunch area to be the same, but the rf voltage has been cranked up to V(sub rf) 4.00 MV.
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摘要 :
We analyze the stability issues of the 3 TeV low-field collider. Some relevant properties of the collider are listed in Table 1. In the table, the rms bunch length of (sigma)(sub l)=0.50 m and bunch area of A=1.50 eV-s at injectio...
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We analyze the stability issues of the 3 TeV low-field collider. Some relevant properties of the collider are listed in Table 1. In the table, the rms bunch length of (sigma)(sub l)=0.50 m and bunch area of A=1.50 eV-s at injection are extraction values from the Main Injector. At extraction of this 3 TeV ring, we assume the bunch area to be the same, but the rf voltage has been cranked up to V(sub rf) 4.00 MV.
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The paper details the 1996 design effort for the IFMIF HEBT. Following a brief overview, it lists the primary requirements for the beam at the target, describes the design approach and design tools used, introduces the beamline mo...
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The paper details the 1996 design effort for the IFMIF HEBT. Following a brief overview, it lists the primary requirements for the beam at the target, describes the design approach and design tools used, introduces the beamline modules, gives the results achieved with the design at this stage, points out possible improvements and gives the names and computer locations of the TRACE3-D and PARMILA files that sum up the design work. The design does not fully meet specifications in regards to the flatness of the distribution at the target. With further work, including if necessary some backup options, the flatness specifications may be realized. It is not proposed that the specifications, namely flatness to (+-)5% and higher-intensity ridges that are no more than 15% above average, be changed at this time. The design also does not meet the requirement that the modules of all beamlines should operate at the same settings. However, the goal of using identical components and operational procedures has been met and only minor returning is needed to produce very similar beam distributions from all beamlines. Significant further work is required in the following areas: TRACE3-D designs and PARMILA runs must be made for the beams coming from accelerators No. 3 and No. 4. Transport of 30-MeV and 35-MeV beams to the targets and beam dump must be studied. Comprehensive error studies must be made. These must result in tolerance specifications and may require design iterations. Detailed interfacing with target-spot instrumentation is required. This instrumentation must be able to check all aspects of the specifications.
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