Flex-Boron Sheet

JC238 Flex Boron

JC238 Flex-Boron is a flexible neutron shielding material useful for shielding irregular shapes as well as for being adhered to large straight or curved vertical surfaces. It can be cut to size with a utility knife and bent in a radius as small as 6.4mm (¼”). It can also be custom moulded to virtually any configuration; a common application being cylinders with lids for shielding detectors.

JC238 Flexi-Boron has a high boron concentration that provides a thermal neutron attenuation factor greater than X250 for the standard 1/8” (3.2 mm) thickness. It will withstand temperatures of up to 205°C (400°F) without loss of physical or nuclear properties and is self-extinguishing when exposed to flame.

Two standard sizes of Flex-Boron are available
JC238A is 305 x 610 mm (12” x 24”)
JC238B is 610 x 914 mm (24” x 36”)
Both are 3.2 mm (1/8”) thick. Other sizes and thicknesses are available
to meet your specific application requirements.

  • High temperature, flexible shielding material
  • Contains 25% boron by weight that is uniformly distributed throughout a silicon elastomer matrix
  • Available in sheet form or custom shapes and sizes
Composition Data
Hydrogen atom density / cm³: 2.7 x 10²²
Hydrogen weight percent 2.76
Boron atom density / cm³: 2.51 x 10²²
Natural boron isotope distribution: 19.6% ¹⁰B and 80.4 % ¹¹B
Boron weight percent: 27.60%
Total Density: 1.64 g/cm³ (102 lbs./ft³)
Radiation Properties
Macroscopic thermal neutron cross section: 18.9 (cm⁻¹)
Gamma resistance: 1 x 10¹⁰ rad
Neutron resistance: 5 x 10¹⁸ n/cm²
Physical Properties
State: Rubbery solid
Colour: Black
Odour: No odour
Machinability: Poor but easy to cut
Thermal Properties
Recommended Temperature Limit: 205°C (400°F)
Percent volatile by volume 0
Chemical Properties
Chemical Name & Synonyms: Flexi-Boron
Trade Name & Synonyms: JC238
Chemical Family: Boron compound with silicone elastomer
Solubility in Water: Negligible
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