Ra-224 is usually in divalent state.
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)%).
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.
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
|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-|
|Processing||Off-line mass separation|
|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.|
|pH (pH strips)||n.a.|
|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|