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Specialized Crystal Growth and Material Characterization


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Microelectronics; Advanced Materials OBJECTIVE: Develop advanced Material and process for quality crystal growth to aid mission support effort. DESCRIPTION: The objective of this topic is to develop innovative crystals that are transparent in the vacuum ultraviolet (VUV) region of the electromagnetic spectrum and host thorium dopants at a concentration of 1016-1017 thorium atoms per cubic centimeter. The thorium-doped crystals should be either thorium doped into CaF2 and/or thorium doped into MgF2. The ability to produce both CaF2 and MgF2 crystals is preferred. The crystals must transmit VUV light down (>99% bulk transmission to at least 140 nm which would require very low levels of impurities, such as oxygen). Also exploring other large bandgap crystals and showing their capability is highly encouraged with this request. For this topic, foreign nationals shall be restricted from participating in all phases. Development and demonstration of crystal growth under Phase II will likely involve Controlled Unclassified Information (CUI), which requires application of technical and non-technical controls described in DoDI 5200.48 and NIST SP 800-171. PHASE I: Demonstrate a proof-of-concept that one can grow/develop a crystal that is transparent in VUV region of the electromagnetic spectrum and able to host radioactive dopants. Also, a clear indication of growing low-impurity, VUV crystals i.e. MgF2, CaF2, purification of material as well as show property characterization of the crystal material. Develop a Phase II plan that includes the ability to handle radioactive material in the facility that foresee future crystal development with such dopants. PHASE II: Demonstrate and develop a method to grow crystal from ~1mg of dopant as starting materials for the crystal and less quantity in some cases. Clearly present an example and prototype of crystal with exact amount of dopant in the first 6 months. As part of this phase a method for sectioning and polishing for example (two 3 mm x 3 mm faces of the crystal and one of the 3 mm x 10 mm) must be demonstrated and developed. • Methods for ascertaining the amount of thorium dopant in the crystals must be verified • The ability, now or planned, to handle thorium isotopes in the SBIR facility must be verified • The capability to deliver thorium doped crystals as part of the phase II. • Grow and provide prototype crystals with roughly 3 mm x 3 mm x 10 mm dimensions with surface polish of at least Lambda/4. PHASE III DUAL USE APPLICATIONS: Apply the knowledge gained in Phase II to grow and distribute this specialized quality doped material for DOD and other commercially interested partners of this development. A manufacturing plan to facilitate a smooth transition would be ideal. REFERENCES: 7. Peik, E. & Tamm, C. Nuclear laser spectroscopy of the 3.5 eV transition in 229Th. Euro. Phys. Lett. 61, 181 (2003); 8. Campbell, C. J., Radnaev, A. G. & Kuzmich, A. Wigner crystals of for optical excitation of the nuclear 229Th isomer. Phys. Rev. Lett. 106, 223001 (2011); 9. Rellergert, W. G. et al. Constraining the evolution of the fundamental constants with a solid-state optical frequency reference based on the 229Th nucleus. Phys. Rev. Lett.104, 200802 (2010); 10. Kazakov, G. A. et al. Performance of a 229Thorium solid-state nuclear clock. New J. Phys. 14, 083019 (2012). KEYWORDS: Advanced Materials; Crystal Growth; Radioactive Dopant
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