| Paper | Title | Page |
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| TUPTS090 | Experimental Results of Dense Array Diamond Field Emitters in RF Gun | 2134 |
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| We present experimental emission results from arrays of diamond field emitter tips operating in an RF gun at the Argonne Cathode Test-stand. Results from various arrays will be presented with different spacing between array elements. Very high charge densities were produced at various field gradients. The maximum field gradient for a particular geometry was discovered and break-down effects will be presented. Cathode lifetime was preliminarily studied. Further experiments are being planned and work on the cathode design optimization to produce higher quality beams will be discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS090 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| MOPRB067 | High-gradient Single Cycle Terahertz Accelerating Structures | 731 |
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| Recently, gradients on the order of 1 GV/m level have been obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we propose arrays of parabolic focusing micro-mirrors with common central. These novel structures could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of several millimeters long, multi-cell structure which has been testing with electron beam. We also propose using of structures where necessary GV/m E-fields are excited by a drive bunch travelling in the corrugated waveguide. The radiated by drive bunch sequence of short range delayed wakes are guided in this case by metallic disks and reflected back being focused exactly at time when the witness bunch arrives. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB067 | |
| About • | paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| WEPRB072 | Ultra-High Gradient Short RF Pulse Gun | 2987 |
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Funding: DOE SBIR DE-SC0018709 High brightness beams enable novel applications like x-ray free electron lasers and ultrafast electron microscopes. High brightness beams essentially consist of a large number of electrons in a small phase space volume, i.e. a high peak current. When such beams are generated from the cathode, there is a strong space charge force, which elongates the bunch and reduces its brightness. An optimal solution is to raise the accelerating voltage in the gun. However, the maximum gradient is limited by the effects of RF breakdown. The probability of RF breakdown is reduced as the RF pulse length decreases. We present a development of an electron photoinjector operating with short RF pulse, 10 ns scale. We have designed an X-band gun including the RF design, beam quality optimization, and engineering. The gun will be fed by 10 ns, 300 MW RF pulse generated at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. We also manufactured an aluminum prototype and measured its microwave properties, most importantly, fill time. The proposed high brightness beam source can be used as the main beam in wakefield accelerators. It will find commercial applications in ultrafast electron diffraction and microscopy systems. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB072 | |
| About • | paper received ※ 21 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019 | |
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| WEPRB073 | CW Room Temperature Accelerating Structures | 2990 |
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| To this day CW linear electron accelerators were based only on expensive and bulky (embedded in a cryostat) superconducting accelerating structures. CW regime can in principle be realized with normal conducting structures provided the shunt impedance is high. Such structures can be designed using dielectrics (ultra-pure ceramics in C-band and diamond in mm-waves) with ultra-low loss tangent (~10-6). The use of dielectrics allows to concentrate the electromagnetic energy density in the dielectric region and thus minimize fields and ohmic loss on metallic walls. The thermal loss in dielectric can be relatively low given the loss tangent is small. We report here the design of structures with shunt impedance on the order of 104 MOhm/m, which is several orders of magnitude higher than shut impedance in copper structures in GHz and THz range. High shunt impedance makes it possible to accelerate electrons to 1 MeV using kW-level CW RF sources like magnetrons in C-band and gyrotrons in THz range. Such CW accelerators will find applications in sterilization, food irradiation, industrial radiography and cargo inspection. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB073 | |
| About • | paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |