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SCOPE
This specification defines the requirements for brazed or
diffusion bonded beryllium x-ray window assemblies for mammography related
applications using a variety of frame materials and beryllium sheet produced
from ingots cast using vacuum melted input material and is designated IS-50M™.
JOINING METHOD
Beryllium will be joined to customer-designed frames. High Temperature brazed components will be
bakeable to 1,200oF (650oC) and there will be no braze alloy migration more
than 0.060" (1.5mm) into the clear line of sight. Diffusion bonded components will be bakeable
to 840oF (450oC) and will maintain a clear line of sight that matches the frame
aperture. All joints will be vacuum
tight, defined as no detectable leakage when tested with a helium mass
spectrometer leak detector with a sensitivity of 1 x 10-9 atm-cc/sec.
AVAILABILITY
Sheet to
this specification is available only as brazed or diffusion bonded x-ray window
assemblies. The beryllium thickness
range is 0.020" (0.5 mm) up to and including 0.125" (3.2 mm). The window aperture can be rectangular,
circular, or other configurations.
BERYLLIUM
COMPOSITION
The vacuum cast beryllium ingot to make x-ray window
assemblies to this specification shall meet the following chemical limits:
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Be Assay
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99.0%
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Minimum
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Maximum
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Maximum
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Be Oxide
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0.50%
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Lead
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0.002%
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Aluminum
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0.09%
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Magnesium
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0.08%
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Calcium
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0.02%
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Manganese
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0.02%
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Carbon
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0.10%
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Molybdenum
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0.002%
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Chromium
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0.04%
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Nickel
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0.05%
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Cobalt
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0.001%
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Silicon
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0.06%
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Copper
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0.01%
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Silver
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0.0005%
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Iron
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0.15%
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Zinc
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0.02%
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Other metallic
impurities as determined by normal spectro-graphic techniques. Beryllium may be determined by difference
(i.e. 100% - other elements).
Detailed analytical procedures used by BW-Electrofusion
Products are available upon request.
BERYLLIUM MATERIAL
SPECIFICATIONS
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Surface Quality: Material shall be uniform in quality and condition, clean, sound, and
free from foreign materials and from internal and external imperfections
detrimental to fabrication or to performance of parts.
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Surface Finish: The surface finish of standard sheet shall be 63
micro-inches Ra or better. Various thicknesses may be available in different surface
finishes. Please consult
BW-Electrofusion for availability.
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Thickness Tolerances:
0.020" to 0.025" ±
0.002"
0.026" to 0.055" ±
0.003"
0.056" to 0.075" ±
0.004"
0.076" to 0.125" ±
0.006"
Special tolerances on
are available on request. Please consult
Brush Wellman - Electrofusion Products for price and availability.
PACKAGING
Material will be appropriately identified, packaged, and
labeled to comply with applicable government regulations and/or standard
procedures of Brush Wellman - Electrofusion Products.
HEALTH
AND SAFETY
Handling beryllium in solid form poses no
special health risk. Like many
industrial materials, beryllium-containing materials may pose a health risk if
recommended safe handling practices are not followed. Inhalation of airborne beryllium may cause a
serious lung disorder in susceptible individuals. The Occupational Safety and Health
Administration (OSHA) has set mandatory limits on occupational respiratory
exposures. Read and follow the guidance
in the Material Safety Data Sheet (MSDS) before working with this
material. For additional information on
safe handling practices or technical data on beryllium, contact Brush Wellman
Inc. - Electrofusion Products.
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