1. Nuclear Reactions

2. Artificial Radioactivity
In 1934 Irene and Jean Joliot-Curie transmuted aluminum to phosphorus.
Alpha bombardment
Unstable state of P-31
The remaining sample continued to emit positrons.
P-30 is radioactive
Half-life 2.5 min
Artificial radioisotope

3. Conservation Laws Nuclear reactions follow conservation laws.
Conservation of energy, linear momentum, angular momentum
Conservation of charge
Conservation of mass number
Conservation of charge is equivalent to proton count plus electrons and positrons.
Za + ZX = ZY + Zb
Conservation of mass number is equivalent to a count of protons plus neutrons.
Aa + AX = AY + Ab
Conservation of energy uses relativistic mass energy.

4. Reaction Energy
The conservation of energy requires a table of mass energies for individual isotopes.
Not elemental mass
Use atomic mass units and convert to MeV to get energy.
1 u = MeV/c2
Add kinetic energy as needed
Q value is mass difference

5. Exothermic A reaction with a positive Q releases energy.
No additional kinetic energy for input
The energy released becomes kinetic energy for the daughters.
Production of carbon-14 is exothermic.
Mn =
MN14 =
Mp =
MC14 =
The mass difference gives Q.
Q = MeV

6. Endothermic A reaction with a negative Q requires energy.
Must come from initial kinetic energy
There is a threshold kinetic energy for production.
Production of carbon-14 is exothermic.
Mp =
MO18 =
Mp =
Mn18 =
The mass difference gives Q.
Q = MeV

7. Medical Isotopes next Radioisotopes are important medical tools.
Isotopes can be used for imaging internal organs.
Scintigraphs
SPECT
PET
Energy deposition can be used for treatment.
Tumor treatment
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