Radon-implanted 214Po and anomalous pulses in sodium iodide detectors for dark matter

214Po is implanted into surfaces exposed to radon. The implantation rate could be sufficient to explain the rate of low-energy events with anomalously fast scintillation pulses that has been observed in sodium iodide crystals used in a search for WIMP dark matter. The rate should be closely coupled in time to the radon concentration.