Sodium -22 (Na-22)

DOE-HDBK-1106-97

SODIUM-22 (Na-22)

Instructor's Notes

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, sodiumiodide

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 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.