BORAL

[Lester Slaback <Lester.Slaback@NIST.GOV>]

General info for those interested:
BORAL is a patented name and material consisting of boron carbide
sandwiched between aluminum.  It comes in various thicknesses so you
basically can select the amount of boron needed for your THERMAL neutron
attenuation.
But you can also get borated aluminum (an actual alloy) that is much more
malleable than BORAL, albeit in lower boron concentrations.  Also available
is a borated rubber compound (great for wrapping around objects) ans a
lithiated rubber compound (no capture gamma like boron has).  The latter
material are available in isotopic enriched versions (for more $$) to make
up for their typically low concentrations of thermal nerutron absorbing
material.

Typically these materials are of interest where fast neutrons are not an
issue (i.e., already removed) or where thermal neutrons are the paramount
issue (e.g., detectors in various reactor experiments).
Disclaimer:  the above are the personal musings of the author, and do not
represent any past, present, or future position of NIST, the U.S. government,
or anyone else who might think that they are in a position of authority. 
Lester Slaback, Jr.  [Lester.Slaback@NIST.GOV] 
NBSR Health Physics 
Center for Neutron Research 
NIST
100 Bureau Dr.  STOP 3543 
Gaithersburg, MD  20899-3543 
301 975-5810 voice
301 921-9847 fax
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