Lithium Polyethylene


JC215 is an effective neutron shield that uses lithium instead of boron as the thermal neutron absorber. 

Thermal neutrons captured by boron produce a 420 keV capture gamma that in some cases may be undesirable. Lithium does not produce a capture gamma, but since lithium has a lower thermal neutron cross-section than boron, your application will require a thicker shield to attain the same shielding factor as for boron loaded polyethylene.

JC215 is available in a wide range of form factors including slabs, bricks, cylinders, and other custom shapes.  It is easily machined using common wood- and metal-working tools.  JCS can not only provide custom machining but can also pour JC215 into custom made moulds to reduce the machining necessary for more complex application-specific shielding forms.

  • Useful for shielding detectors in neutron fields as Lithium does not emit capture gammas when thermal neutrons are absorbed
  • High hydrogen content with 7.5% lithium
  • Shields using enriched lithium 6
  • Available in slabs, cylinders, and other custom shapes
  • Other lithium concentrations on request
Composition Data JC215
Hydrogen atom density / cm3: 5.44 x 10²²
Hydrogen weight percent: 8.59%
Lithium atom density / cm3: 6.96 x 10²¹
Lithium natural isotope distribution: 92.6 % ⁷Li and 7.4 % ⁶Li
Weight percent of all isotopes of lithium: 7.56%
Total Density: 1.06g/cm³ (66.2 lbs./ft³)
Radiation Properties
Macroscopic thermal neutron cross section: 0.51 (cm⁻¹)
Gamma resistance: 5 x 10⁸ rad
Neutron resistance: 2.5 x 10¹⁷ n/ cm²
Physical Properties
State: Bricks, slabs, cylinders
Color: Off white / Yellow
Odor: No odor
Machinability: Excellent
Thermal Properties
Recommended Temperature Limit: 180 °F (82.2 °C)
Chemical Properties
Chemical Name & Synonyms: Lithium Polyethylene
Trade Name & Synonyms: JC215
Chemical Family: Polyolefin’s
Formula: Mixture (CH²)n, Li
Solubility in Water: Negligible
Reactive Acids: Incompatible w/concentrate acids, Releases CO₂
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