A Rn-222 Source for Low-background Liquid Scintillation Detectors M. Johnson, J. Benziger, C. Stoia, F. P. Calaprice, M. Chen, N. Darnton, F. Loeser and R.B. Vogelaar. Nuclear Instruments and Methods – A Volume 414, Issues 2–3, 11 September 1998, Pages