AVS 60th International Symposium and Exhibition
    Vacuum Technology Tuesday Sessions
       Session VT+EN+TF-TuA

Paper VT+EN+TF-TuA10
Vacuum Environment Processing Studies for the Production of Commercial Thin Film Hydride Targets

Tuesday, October 29, 2013, 5:00 pm, Room 202 C

Session: Vacuum for Industrial Processing
Presenter: J.L. Provo, J. L. Provo, Consulting
Correspondent: Click to Email

An important aspect of understanding industrial processing is to know the characteristics of the materials used in such processes. A study was performed to study the effects of hydriding chamber material on the degree of hydriding for the commercial production of thin film hydride targets for various research universities, used in their accelerators for cancer research, and material studies, for the oil industry for oil well logging, for industrial nuclear waste assay, and for the Federal Aviation Administration (FAA) for contraband studies at ports and airports. It was desired to increase the degree of hydriding of various thin film hydrides and to study the vacuum environment during air- exposure hydriding. For this purpose dynamic residual gas analysis during deuterium gas hydride processing was utilized, employing a special set –up for direct dynamic hydride gas sampling for a process at elevated temperature and full gas pressure. Complete process data for a stainless-steel air fired passivated externally heated pipe type hydriding chamber is given and dynamic residual gas analysis comparisons during hydriding are presented for similar chambers constructed of alumina(99.8%), copper with an interior coating of aluminum, and for a wet hydrogen fired passivated copper-beryllium(1.83%) chamber. Dynamic data with gas in chamber at hydriding temperature showed the presence and growth of water vapor(D2O) and related ion species( H2O⁺, HDO⁺, D2O⁺, and OD⁺ ) during a one hour process time. Extensive hydrogen isotope exchange reactions were seen to be taking place. Mass peaks 12(C⁺), 16(CD2), 17(CHD2⁺), and 18(CD3⁺, OD⁺) grow for approximately the first half hour of a one hour hydriding process and then come to an equilibrium. Mass peaks 19(HDO⁺) and 20(D2O⁺) continue to grow throughout the process cycle. Copper-beryllium(1.83%) passivated hydriding chambers were seen to be the best hydriding chamber material studied to date.