Radioactive Decay Speedup at T= K-5: Electron-Capture Decay Rate of Be-7 Encapsulated in C-60

Jun 22, 2007
4 pages
Published in:
  • Phys.Rev.Lett. 98 (2007) 252501,
  • Phys.Rev.Lett. 101 (2008) 219901 (erratum)

Citations per year

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Abstract: (APS)
The electron-capture (EC) decay rate of Be7 in C60 at the temperature of liquid helium (T=5  K) was measured and compared with the rate in Be metal at T=293  K. We found that the half-life of Be7 in endohedral C60 (Be7@C60) at a temperature close to T=5  K is 52.47±0.04  d, a value that is 0.34% faster than that at T=293  K. In this environment, the half-life of Be7 is nearly 1.5% faster than that inside Be metal at room temperature (T=293  K). We then interpreted our observations in terms of calculations of the electron density at the Be7 nucleus position inside the C60; further, we estimate theoretically the temperature dependence (at T=0  K and 293 K) of the electron density at the Be nucleus position in the stable center inside C60. The theoretical estimates were almost in agreement with the experimental observations.
  • 27.20.+n
  • 23.40.Hc
  • 21.10.Tg
  • 36.40.Cg