Testing a solution of the nuclear
waste problem
Does matter change the halflife of unstable nuclei
Debye plasma model
Enhancement factor due to electron screening:
“Clearly, an improved theory is highly desirable to
explain why the simple Debye model appears to work
so well”
It does not work that well
Works ok for cross sections ([1],[2]) but not for half-lifes:
Wang et al. [3] measure 0.7%. Theory predicts 1.4% (ec)
Limata et al. [4] measure 1.2%. Theory predicts 14% (β+)
We measure 0.9%. Theory predicts 62% (α)
For 226Ra theory predicts t½=1600 years → t½=1.3 years
Our experiment
Implant 221Fr (α-unstable) into Au, W, Si and Plastic
No papers published so far
ISOLDE layout
221Fr
decay chain
221Fr
decay chain
Results
Results
Results
Future work

Other nuclei ~ e.g. 224Fr

Other temperatures ~ 4K  factor 8.5 on Ue

Other materials
References
[1] Raiola et al.: J. Phys. G 31 (2005) 1141
[2] Cruz et al.: Phys. Lett. B 624 (2005) 181
[3] Wang et al.: Eur. Phys. J. A 28 (2006) 375
[4] Limata et al.: Eur. Phys. J. A 28 (2006) 251