Vacuum outgassing of artificial dielectric ceramics
- Continuous Electron Beam Accelerator Facility, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States)
A special aluminum nitride (AlN)--glassy carbon artificial dielectric ceramic for microwave absorption at low temperature has been developed at the Continuous Electron Beam Accelerator Facility to manufacture the higher order mode (HOM) loads used in the superconducting cavities of the machine. As the HOM loads share the same ultrahigh vacuum as the superconducting cavities, very tight vacuum requirements are imposed on the HOM load's material. Vacuum outgassing rates have been measured and compared for AlN--15% glassy carbon artificial ceramic in fully degassed condition produced by heating to high temperature in a vacuum furnace. In addition, the effect of exposure to air, nitrogen gas, and isopropanol is discussed. A typical outgassing rate at room temperature is 2.5[times]10[sup [minus]11] Torr l/s/cm[sup 2], 24 h after initial pump down. Baking 24 h at 150 [degree]C was sufficient to attain an outgassing rate of less than 4[times]10[sup [minus]12] Torr l/s/cm[sup 2]. However, when the ceramic has a lower bulk density or a higher apparent porosity, the outgassing rates can be two orders of magnitude higher.
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 7084510
- Journal Information:
- Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States) Vol. 12:4; ISSN 0734-2101; ISSN JVTAD6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACCELERATORS
ALUMINIUM COMPOUNDS
ALUMINIUM NITRIDES
CARBON
CAVITY RESONATORS
CEBAF ACCELERATOR
CERAMICS
DEGASSING
DIELECTRIC MATERIALS
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
LINEAR ACCELERATORS
MATERIALS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
PNICTIDES
RESONATORS
SORPTIVE PROPERTIES
SUPERCONDUCTING CAVITY RESONATORS
SUPERCONDUCTING DEVICES
SURFACE PROPERTIES
VACUUM SYSTEMS