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Estimates Of Energy Fluence at the Focal Plane In Beams Undergoing Neutralized Drift Compression.

DE2009945561

Publication Date	2008
Personal Author	Barnard, J. J.; Seidl, P. A.; Coleman, J. E.; Ogata, D.; Welch, D. E.
Page Count	5
Abstract	We estimate the energy fluence (energy per unit area) at the focal plane of a beam undergoing neutralized drift compression and neutralized solenoidal final focus, as is being carried out in the Neutralized Drift Compression Experiment (NDCX) at LBNL. In these experiments, in order to reach high beam intensity, the beam is compressed longitudinally by ramping the beam velocity (i.e. introducing a velocity tilt) over the course of the pulse, and the beam is transversely focused in a high field solenoid just before the target. To remove the effects of space charge, the beam drifts in a plasma. The tilt introduces chromatic aberrations, with different slices of the original beam having different radii at the focal plane. The fluence can be calculated by summing the contribution from the various slices. We develop analytic formulae for the energy fluence for beams that have current profiles that are initially constant in time. We compare with envelope and particle-in-cell calculations. The expressions derived are useful for predicting how the fluence scales with accelerator and beam parameters.
Keywords	Beam dynamics Neutron fluence Compression Drift Solenoids Accelerators Plasma Velocity Space charge
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200911
Contract Number	W-7405-ENG-48

Estimates Of Energy Fluence at the Focal Plane In Beams Undergoing Neutralized Drift Compression.

Estimates Of Energy Fluence at the Focal Plane In Beams Undergoing Neutralized Drift Compression.
DE2009945561

Publication Date	2008
Personal Author	Barnard, J. J.; Seidl, P. A.; Coleman, J. E.; Ogata, D.; Welch, D. E.
Page Count	5
Abstract	We estimate the energy fluence (energy per unit area) at the focal plane of a beam undergoing neutralized drift compression and neutralized solenoidal final focus, as is being carried out in the Neutralized Drift Compression Experiment (NDCX) at LBNL. In these experiments, in order to reach high beam intensity, the beam is compressed longitudinally by ramping the beam velocity (i.e. introducing a velocity tilt) over the course of the pulse, and the beam is transversely focused in a high field solenoid just before the target. To remove the effects of space charge, the beam drifts in a plasma. The tilt introduces chromatic aberrations, with different slices of the original beam having different radii at the focal plane. The fluence can be calculated by summing the contribution from the various slices. We develop analytic formulae for the energy fluence for beams that have current profiles that are initially constant in time. We compare with envelope and particle-in-cell calculations. The expressions derived are useful for predicting how the fluence scales with accelerator and beam parameters.
Keywords	Beam dynamics Neutron fluence Compression Drift Solenoids Accelerators Plasma Velocity Space charge
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200911
Contract Number	W-7405-ENG-48