At-211 decays with 7.214(7) h half-life. It decays by 58.2% electron capture to short-lived Po-211 (T1/2 = 0.516(3) s) that decays in turn with 100% alpha emission to stable Pb-207. Moreover, At-211 decays by 41.8% alpha emission to quasi-stable Bi-207 (T1/2=31.6 years; only 26 Bq Bi-207 per 1 MBq of At-211 after decay of the latter) that decays in turn to stable Pb-207. Including its short-lived Po-211 daughter, the cumulative alpha emission is 100% per At-211 decay with an average alpha energy of 6.78 MeV.
Moreover, At-211 and its daughter Po-211 in equilibrium emit weak gamma-rays at 567.7 keV (0.31%), 687.0 keV (0.26%) and 897.8 keV (0.32%).
The mean alpha energy per decay is 6785 keV, the mean recoil energy (of Bi-207 or Pb-207 recoils respectively) is 131 keV, the mean electron energy per decay is 3 keV, and the mean photon energy per decay is 43 keV.
At-211 is produced by alpha particle irradiation of metallic Bi-209 targets at the cyclotron ARRONAX.
The radiochemical separation is performed at ARRONAX (ARRONAX, Nantes, France) and activity will be shipped from there to the users.
Examples of use
|Daughter||Po-211 which decays immediately (T1/2=0.5 s) to stable Pb-207 (stable) and Bi-207 that is quasi-stable (T1/2=31.6 y).|
|Branching Ratio/Decay||41.8 % α, then EC at 100%|
58.2% EC, then α at 100%
|Radionuclidic Purity||At-210/At-211 < 0.5%|
|Identification||569.7 keV, 687.0 keV and 897.8 keV gamma lines present|
|Appearance||Clear and colourless solution|
|Activity available||Tens of MBq|
|Grade||Preclinical grade, n.c.a.|
|Other information||Transport to be discussed.|