Sodium-22 (Na-22) - doe-hdbk-1106-97

DOE-HDBK-1106-97

SODIUM-22 (Na-22)

Sodium-22 is a positron emitter (positive beta particle/electron) and high-energy gamma emitter.

It also emits an annihilation photon when the positive electron is annihilated with a negative

electron, producing pure energy.

Sodium-22 is detected with a thin-window G-M probe, sodium-iodide scintillation counter, or

liquid scintillation detector.

1. Energy:

Maximum beta energy: 0.546 MeV, average energy 0.182 MeV.

Gamma energy: 1.275 MeV.

Annihilation photon: 0.511 MeV.

2. Maximum beta range in air: 4.7 feet (1.4 m).

3. Unshielded dose rate from 1mCi point source at 1/2 inch (1cm): 11.8 rad/hr.

4. IAEA toxicity classification: High-medium.

5. Physical half-life: 950 days.

6. Effective half-life (Teff): 10.9 days.

7. Critical organ:

Whole body for intake of transportable compounds.

Lungs for inhalation.

Lower large intestine for ingestion.

8. Personnel monitoring: dosimeter and finger rings, uptakes may be determined by

urinalysis.