Chemical properties
In the periodic table astatine is situated at the boundary of halogens and metalloids, i.e. partly behaves like a halogen and partly like a metal. This requires dedicated labelling strategies .
Nuclear properties
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% ɑ emission to stable Pb-207. Moreover, At-211 decays by 41.8% ɑ 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 ɑ emission is 100% per At-211 decay with an average ɑ energy of 6.78 MeV.
At-211 emits X-rays, notably Kα at ≈78 keV (33.1(5)%) and Kβ at ≈90 keV (9.06(5)%). These energies enable SPECT-imaging, preferably with medium energy collimators .
Moreover, At-211 and its daughter Po-211 in equilibrium emit weak γ-rays at 567.7 keV (0.31%), 687.0 keV (0.26%) and 897.8 keV (0.32%).
The mean ɑ 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.
Production
At-211 is produced by ɑ particle irradiation of metallic Bi-209 targets at the cyclotron ARRONAX.
Distribution
The radiochemical separation is performed at ARRONAX (ARRONAX, Nantes, France) and activity will be shipped from there to the users.
Examples of use
| Parameter | Specifications |
|---|---|
| Production route | Bi-209(α,2n) At-211 |
| Daughter | Decays to Po-211 which decays immediately (T1/2=0.5 s) to stable Pb-207 and Bi-207 that is quasi-stable (T1/2=31.6 y): cumulative 100% α, 100% EC |
| Half-life | 7.21 h |
| Processing | Dry extraction |
| Primary Container | 2.5 mL borosilicate glass V-vial with silicon rubber screw cap |
| Product Grade | n.c.a. |
| Physical Form | Solid |
| Chemical Form | Chloroform |
| Radioactive Concentration (gamma spectrometry) | n.a. |
| Appearance | Clear colourless solution |
| Radionuclide identification (gamma spectrometry) | 570 keV, 687 keV and 898 keV gamma lines present |
| Radionuclidic Purity (gamma spectrometry) | At-210/At-211 < 0.5% |
| Chemical purity (ICP-OES) | n.a. |
| Molar activity (ICP-OES) | n.a. |
| Apparent Molar Activity | n.a. |
| Microbiological quality | n.a. |
| Bacterial endotoxin | n.a. |
| pH (pH strips) | n.a. |
| Additional information | |
| Activity available | Tens of MBq on demand |
| Activity limit for UN2910 (excepted package) shipment | 0.5 GBq in dry state or 50 MBq in liquid form |
| Other information |