| Paper | Title | Page |
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| FR5RFP013 | Fabrication of Micro-Scale Metallic and Dielectric Accelerator Structures with Sub-Wavelength Features | 4556 |
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The millimeter-scaleμAccelerator Platform (MAP)–essentially a “particle accelerator on a chip”–will ultimately allow for revolutionary medical and industrial applications due to its manageable size and reproducibility. The MAP consists of an electron source and an all-dielectric, laser powered, particle accelerator. The dielectric structure has two slab-symmetric reflecting mirrors with a vacuum gap between them. A periodic coupling mechanism allows laser power to enter transversely through one mirror. This mechanism is analogous to the slots of an optical diffraction grating, with coupling period and vacuum gap equal to the wavelength of the laser (800nm in this study). Work to date has included designing, fabricating and testing a prototype relativistic structure using a patterned gold layer. To go further, we have studied the fabrication techniques and electromagnetic designs of an all-dielectric (non-metallic) structure. Fabrication of the final structure is modeled after Vertical-Cavity Surface-Emitting Lasers (VCSEL) and Distributed Bragg Reflector (DBR) techniques. Preliminary numerical studies of the sub-relativistic structure are also presented. |
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| FR5RFP014 | Testing of Laser-Driven Resonant Accelerating-Structures Possessing Sub-Wavelength Periodic Features | 4559 |
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The Micro-Accelerator Platform, a laser-driven accelerating device measuring less than a millimeter in each dimension, has a variety of applications in industry and medicine. The structure consists of two parallel slabs, with each possessing reflective surfaces and with one having periodic slots which allows transversely incident laser light to enter the gap between the two planes. The resonance of the electric field created in the gap can be measured indirectly through the spectral response of the device. Using a combination of an interferometer and a fiber coupled spectrometer, prototype structures are aligned and measured. With the aid of a nanometer-accuracy positioning device, the bottom slab (a mirror) is aligned with the top slotted-structure. The interferometer and a low power laser are used to position the slabs. A 800nm Titanium-Sapphire oscillator with a bandwidth of greater than 100nm is used for the spectral measurements. The spectra of both transmitted and reflected beams have been measured for a number of structures and are compared to simulation results. Various improvements to the initial measurement system as well as alternative future approaches are discussed. |
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| FR5RFP015 | Testing of a Laser-Powered, Slab-Symmetric Dielectric Structure for Medical and Industrial Applications | 4562 |
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Funding: This project is supported by DOE SBIR Grant DE-FG02-08ER85038. Laser-powered dielectric accelerating structures, which have attracted attention in recent years, trade fabrication challenges and extremely small beam apertures for the promise of high gradients and new bunch formats. The slab-symmetric, periodically-coupledμAccelerator Platform (MAP) is one such dielectric accelerator, and has been under development through a RadiaBeam-UCLA collaboration for several years. Intended applications of the structure include the production of radiation for medical treatments, imaging, and industrial uses. Prototype MAP structures are now being fabricated, and a program has been undertaken to test this device using externally injected electron beams. Plans are underway to install structures in the E163 facility at SLAC. In this paper we describe the testing methods, diagnostics and expectations. Progress and results to date are also presented. |