Radionuclide Production and Generators

Question 1

Alpha Decay

Answer 1

Occurs in Heavy nuclei; The atomic number 9Z) is reduced by 2 and the mass (a) is reduced by 4

Question 2

Beta Decay

Answer 2

It occurs in neutron-rich nuclei; The atomic number (Z) of the daughter is one more than the parent; the Mass number (A) is not changed.

Question 3

Positron Decay

Answer 3

Occurs in proton-rich nuclei; proton converted to a neutron; The atomic number (Z) of the daughter is one less than the parent; the mass number (A) is not changed.

Question 4

Electron Capture

Answer 4

Positron alternative; electron is “captured” by the nucleus from an orbital shell and combines with a proton to form a neutron.

Atomic Number (Z) of the daughter is one less than the parent. Mass number (A) does not change.

Question 5

Isomeric Transition

Answer 5

Daughter nuclide may still exist in excited state and have excess energy to dispel after beta, positron or electron capture. Excess can be gamma rays.

Question 6

Radionuclide production methods

Answer 6

Fission (in a reactor)
(n,f); neutron-Inititated
produces 2 “daughters” + more neutron + heat;

Neutron Capture (in a reactor)
(n, y)
Thermal neutron capture—–radioactive isotope of parent that decay by beta emission
Fast neutron——-Transmutation

Cyclotron
Charged particles accelerated in “dees”, bombard target material
variety of products possible.

Question 7

Nuclear Fission

Answer 7

Requires heavy nuclei
Neutron accelerated at nucleus at high speed, nucleus breaks into 2 or more pieces, this releases an extreme amount of heat (heat used by nuclear power)

Some piece broken down into Mo-99, I-131, Xe-133

Question 8

Neutron Capture

Answer 8

another nucleus captures alternative to fission neutron released during fission; excited nucleus that decays by gamma ray emission.

Question 9

Global production of Mo-99

Answer 9

Produced exclusively by fission of U-235
Global suppliers:
Kazakhstan, Canada, Australia, Russia, USA

U-235 supplied from france, South Africa, Canada and Argentina

Global Supply of Tc99
Belgium
Netherland
Czech Republic
Poland
Australia
South Africa

Question 10

Carriers in Radionuclide Preparation

Answer 10

Carrier-free -
only the stated radiotracer is present, without its correspoding nonradioavtive tracer

No-carrier added (NCA)
one where unlabeled tracer or precursor is not added intentionally during radionuclide production (Mo-99 production via fission)

Carrier-added
corresponding nonradioactive tracer is added intentionally (Mo99 production via Mo98 neutron capture)

Question 11

Specific Activity

Answer 11

The number of disintegrations per unit weight of a sample
mCi/mg
Bq/kg
Ci/g
(carrier-free radionuclide) -shorter half life, less amount of material required to produce given activity= higher SA