Ultra-low radioactivity Kapton and copper-Kapton laminates

Understand

Polyimide-based materials, like Kapton, are widely used in flexible cables and circuitry due to their unique electrical and mechanical characteristics.

• This study is aimed at investigating the radiopurity of Kapton for use in ultralow background, rare-event physics applications by measuring the $^{238}$U, $^{232}$Th, and $^{nat}$K levels using inductively coupled plasma mass spectrometry.
• Commercial-off-the-shelf Kapton varieties, measured at approximately 950 and 120 pg/g $^{238}$U and $^{232}$Th (1.2$\times$10$^4$ and 490 $\mu$Bq/kg), respectively, can be a significant background source for many current and next-generation ultralow background detectors.
• This study has found that the dominant contamination is due to the use of dicalcium phosphate (DCP), a nonessential slip additive added during manufacturing.