Nuclear energy levels

Question 1

Why is a gamma photon released?

Answer 1

allows the nucleus to release energy

Question 2

WHen is energy needed to be released?

Answer 2

• ‘daughter’ nucleus is formed in an excited state
• energy released when nucleus moves to its lowest energy state
  
  • its ground state
  • usually short lived
• can be done in one step or a few
  
  • shown in an energy level diagram

Question 3

WHat is the techneitium generator used for?

Answer 3

• used in hospital to produce a source which emits gamma radiation only

Question 4

Which isotope is used? WHy is it used?

Answer 4

• 99/43 Tc
• form in an excited state after an alpha or beta emission
• stays in an excited state long enough to be separated from the parent isotope
• said to be in a metastable state

Question 5

How is the metastable state shown and what is the half life of the metastable technetium isotope?

Answer 5

• superscript m
  
  • X^m
• has a half life of 6h

Question 6

Despite the technetium generator being radioactive, how does it effective only release gamma radiation?

Answer 6

• also released beta minus
• has a half life of 500,000 and forms a stable product

Question 7

How is the 99Tc isotope formed?

Answer 7

• beta minus emission from the (90/42) Mo (molybdenum) isotope

Question 8

What is the half life of 99Mo

Answer 8

67 hours

Question 9

What does the technetium generator consist of?

Answer 9

• an ion exchange column, containing:
  
  • ammonium molybdenate exposed to enutron radiation several day earlier
  • make a significant number of Mo nuclei unstable
• when sodium chloride is passed through the column,
  
  • some Cl ions exchange with pertecjmate ions but not with Mo ions
  • some a solution emerges containing 99Tc^m

Question 10

How is the technetium generator used?

Answer 10

• monitoring blood flow through the brain
  
  • sodium pertechnate solution adminstered into veins
• gamma camera
  
  • image internal organs and bones
  • as a stracer