| Paper | Title | Page |
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| THPAN094 | Design Study of a Transverse-to-Longitudinal Emittance Exchange Proof-of-principle Experiment | 3441 |
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Funding: Dr. Sun's work is supported by U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. Transverse-to-longitudinal emittance exchange can be achieved through certain arrangements of dipole magnets and dipole mode rf cavity. Theory on such schemes has been developed in the past several years. In this paper we report our numerical simulations on the emittance exchange using particle tracking codes. Photoelectron beams with energy less than 20 MeV are used, as our purpose of simulations is to study the feasibility of performing such emittance exchange at existing facilities of beam energy at this level. Parametric studies of the dipole magnets and cavity strengths, as well as initial beam parameters, are presented. |
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| FRPMN117 | Pepper-pot Based Emittance Measurements of the AWA Photoinjector | 4393 |
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| The Argonne Wakefield Accelerator (AWA) RF photocathode gun is a 1.5 cell, L-band, RF photocathode gun operating at 80 MV/m, with an emittance compensating solenoid, and a magnesium photocathode and generates an 8 MeV, 1 nC - 100 nC beam. In this paper, we report on a parametric set of measurements to characterize the transverse trace space of the 1 nC electron beam directly out of the gun. The entire experiment is simulated with PARMELA, from the photocathode, through the pepper pot, and to the imaging screen. The transverse trace-space is sampled with a 2-D pepper pot which allows for simultaneous, single-shot measurements, of both the x and y distributions. A series of pepper pots were available during the experiment to increase the dynamic range of emittance measurements. Realistic particle distributions are used for the simulations and are derived from actual laser profiles, which were captured from a virtual cathode and generated with MATLAB-based particle generator. We report both the second moment (emittance) and the detailed phase space distribution over a gun launch phase range of approximately 50 degrees. | ||
| FRPMS037 | Impact of Transverse Irregularities at the Photocathode on High-Charge Electron Bunches | 4027 |
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| Electron beam properties in photoinjectors are strongly dependent on the initial conditions, e.g., non-uniformities in the drive-laser pulse and/or the photocathode surface. We explore the impact of well-defined transverse perturbation modes on the evolution of the electron beam phase space, and paying special attention to how certain types of perturbations mix. Numerical simulations performed with IMPACT-T (both the standard version and a new wavelet-based version) are presented along with experimental results aimed at validating the simulation codes. The experiments are conducted at the Argonne Wakefield Accelerator facility. |