Chemical properties
Ra-224 is usually in divalent state.
Nuclear properties
Ra-224 decays by ɑ decay with a half-life of 3.6316(23) days. Its decay chain involving Rn-220 (T1/2 = 55.6(1) s), Po-216 (T1/2 = 145(2) ms), Pb-212 (T1/2 = 10.622(7) h), Bi-212 (T1/2= 60.55(6) min), either Po-212 (T1/2 = 0.29 µs) or Tl-208 (T1/2 = 3.053(4) min) leads to stable Pb-208. Including its decay chain, the cumulative ɑ emission is 400% per Ra-224 decay with an average ɑ energy of 6.75 MeV.
Ra-224 and daughters emit γ-rays and X-rays. Notable emissions are from Ra-224 at 241.0 keV (4.10(5)%), Pb-212 at 238.6 keV (43.6(5)%), Bi-212 at 727.3 keV (6.67(9)%) and Tl-208 at 2614.5 keV (99.754(4)%) and 583.2 keV (85.0(3)%).
Production
Ra-224 is produced by high energy proton induced spallation of thorium targets at MEDICIS (CERN) followed by an off-line mass separation in order to get a pure Ra-224 sample. The mass-separated ions are implanted into a NaCl layer.
Distribution
Ra-224 is produced at MEDICIS. Activity will be shipped from there to the users in liquid (0.5 M HCl) or dry form.
Examples of use
| Parameter | Specifications |
|---|---|
| Production route | Th-232(p,spallation) |
| Daughter | Decay chain involving radioactive Rn-220, Po-216, Pb-212, Bi-212, Po-212 or Tl-208 leading to stable Pb-208: cumulative 400% α, 200% β- |
| Half-life | 3.6316 days |
| Processing | Off-line mass separation |
| Primary Container | |
| Product Grade | Research, n.c.a. |
| Physical Form | Liquid or solid |
| Chemical Form | Dissolved in maximum 0.2 mL 0.5 M HCl, implanted in solid NaCl layer or deposited on a glass wool |
| Radioactive Concentration (gamma spectrometry) | n.a. |
| Appearance | See chemical forms available above |
| Radionuclide identification (gamma spectrometry) | 241 keV (Ra-224), 238 keV (Pb-212) |
| Radionuclidic Purity (gamma spectrometry) | >99% (possibility of presence of small Ra-223/Ra-225 fraction) |
| 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 | 100 MBq, few times per year (planning several months in advance) |
| Activity limit for UN2910 (excepted package) shipment | 20 MBq (solid form) or 2 MBq (liquid form) |
| Other information | Other forms of delivery to be discussed |