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OALV design with High-k Photoconductor and High-k Optical Window

LLNL researchers has developed designs to augment WBG/UWBG-based OALVs to improve their power handling capability under CW operational environments.  These designs include:

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Cross Section of the High-Voltage Insulator Joint

The approach is to build a high voltage insulator consisting of two materials:  Poly-Ether-Ether-Ketone (“PEEK”) and Machinable Ceramic (“MACOR”).  PEEK has a high stress tolerance but cannot withstand high temperatures, while MACOR has high heat tolerance but is difficult to machine and can be brittle.  MACOR is used for the plasma-facing surface, while PEEK will handle the stresses and high…

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Segments of transmission line lengths can be switched to open circuit (as shown) or shorted to the ground (not shown)

Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength.  The diamond material is specifically doped with substitutional nitrogen, which act as a source of electrons.  The device architecture allows maximum light entering the aperture.  The top and bottom electrodes are made of ultra wide band gap (UWBG)…

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Annular illumination on photo conductor by Conical Total Internal Reflection “CTIR” endcap

The approach is to use a custom-designed frustrum and attach it to the optical fiber that connects to the PCSS.  Light from the fiber enters the frustrum, spreads out, and enters the PCSS.  Any unabsorbed light re-enters the frustrum and, because of its geometry, reflects back into the PCSS itself with only a negligible fraction escaping from the fiber.  The shape of the novel frustrum is…

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An artist’s concept rendering of a 3.5-meter linear induction accelerator (LIA) with four lines-of-sight toward a patient. The blue elements magnetically focus and direct the LIA’s electron beams.

LLNL’s approach is to use their patented Photoconductive Charge Trapping Apparatus (U.S. Patent No. 11,366,401) as the active switch needed to discharge voltage across a vacuum gap in a particle accelerator, like the one described in their other patent (U.S. Patent No.

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OTV Image

The Optical Transconductance Varistor (OTV, formerly Opticondistor) overcomes depletion region voltage limitations by optically exciting wide bandgap materials in a compact package. A 100μm thick crystal could have the capability approaching 40kV and would replace numerous equivalent junction devices. Thus, unlike present junction transistors or diodes, this wide bandgap device can be stacked…