Step 4. Remove sample and standard from tubes and place in separate plastic containers to measure gamma rays.

Step 5. Obtain gamma-ray spectrum for sodium-24 in both sample and standard.

Step 6. Use standard to calculate 1.37 MeV gamma rays counted per minute per gram of sodium (c/m/gNa).

c/m/gNa =

counts/minute measured in 1.37 peak (shaded area above)
grams of sodium known to be in standard (step 1.)

Step 7. Use c/m/gNa and 1.37 MeV gamma rays counted per minute in sample to calculate grams of sodium in sample.

grams Na in sample =