P2 - Nuclear Radiation & Uses of Nuclear Radiation

Question 1

What happens when an unstable nucleus decays?

Answer 1

When an unstable nucleus decays it gives off one or more kinds of nuclear radiation.

Question 2

What are the three types of nuclear radiation given off?

Answer 2

The three types of radiation are: Alpha, beta and gamma.

Question 3

What do these three kinds of radiation all cause?

Answer 3

All three kinds of radiation cause ionization.

Question 4

What happens when the three types of radiation ionize an atom?

Answer 4

They will cause the atoms to gain or lose electrons, turning the atoms into ions.

Question 5

How are positive and negative Ions formed?

Answer 5

Positive Ions are formed when the atoms lose electrons.

Negative Ions are formed when the atoms gain electrons.

Question 6

What is initiation?

Answer 6

Ionization can result in the initiation of chemical reactions between atoms.

Question 7

What can high doses of radiation do to your body?

Answer 7

High doses of radiation can completely kill your cells.

Question 8

How does radiation cause cancer?

Answer 8

When radiation enters human cells it can ionize molecules and damage DNA, this will result in a mutation in the cells causing them to multiply uncontrollably resulting in cancer.

Question 9

What correlation does ionization power have with penetration power?

Answer 9

The greater penetrating it is, the less ionizing it is.

Question 10

What are some characteristics of Alpha Particles?

Answer 10

Alpha particles are relatively, big heavy and slow moving, they consist of 2 protons and 2 neutrons.

Question 11

How penetrating are alpha particles, and how ionizing are they ?

Answer 11

Alpha Particles aren’t very penetrating because their size, they are stopped quickly, alpha can be stopped by paper or skin.
- Alpha particles are also strongly ionizing, they bash into many atoms and knock electrons before they slow down/stop.

Question 12

What are some characteristics of Beta particles?

Answer 12

Beta particles are electrons

• Beta particles are small and move fast
• They can penetrate moderately, further than alpha particles before colliding.
• They are moderately Ionizing
• They can be stopped by a thin sheet of metal, or a few millimeters of aluminium

Question 13

What are some characteristics of Gamma Particles?

Answer 13

Gamma rays are very high frequency Electromagnetic waves.

• They have no mass and no charge
• They can penetrate a long way into materials without colliding, however this means they are weakly ionizing, they tend to pass through materials rather than collide with atoms, however they eventually hit something and do damage.
• They can be stopped by using very thick concrete or a few centimeters of lead.

Question 14

How are Gamma rays produced?

Answer 14

After spitting out an Alpha or a beta particle the nucleus may need to get rid of some extra energy, it does this by emitting a gamma ray, a type of EM radiation.

Question 15

What are some ways to tell what kind of radiation you are dealing with?

Answer 15

You can tell which kind of radiation you’re dealing with by what blocks it, for example:
Placing a piece paper between the radiation source and a Geiger counter and checking the amount of radiation detected, if no radiation is detected then it is an alpha source.

Question 16

What is the most popular application of alpha radiation?

Answer 16

Alpha radiation is used in smoke detectors.

Question 17

How does alpha radiation work in smoke detectors?

Answer 17

Smoke detectors have a weak source of alpha radiation close to two electrodes.

• The radiation ionizes the air and a current flows between the electrodes.
• If there is a fire the smoke will absorb the radiation, therefore the current will stop and the alarm will sound.

Question 18

What is the most popular applications of beta radiation?

Answer 18

Beta radiation is used in Tracers and thickness Gauges for paper.

Question 19

How does beta radiation work as a tracer?

Answer 19

The radioactive source is injected into the patient, or swallowed, the progress is followed around the body using an external radiation detector, the computer converts the reading to a TV display showing where the strongest reading is coming from, these “tracers” can show if the body see working properly.

Question 20

Why do doctors use beta or gamma over alpha?

Answer 20

Doctors use beta or gamma emitters as tracers because this radiation passes out of the body, they must choose things that are only radioactive for a few hours.

Question 21

How is beta radiation used in thickness control?

Answer 21

The radiation is passed through the material, which could be paper or cardboard, the detector on the other side will detect the amount of radiation passing through.
When the amount of detected radiation goes down it means the paper is coming out too thick, the control unit pinches the rollers up to make it thinner, if the reading goes up the papers too thin so the control unit opens the rollers out slightly.

Question 22

Why do you use Beta for measuring paper thickness?

Answer 22

The radioactive substance must not decay away too quickly, otherwise the strength would gradually fall and the control unit would keep pinching up the rollers trying to compensate.
- The beta source is used because the cardboard or paper will partially block the radiation, if the radiation all goes through, or if it doesn’t pass through at all, the reading wont change at all as the thickness changes.

Question 23

How can Gamma radiation be used to treat cancers?

Answer 23

High doses of gamma rays will kill all living cells so they can be used to treat cancers.

Question 24

Why do gamma rays have to be directed carefully?

Answer 24

Gamma rays have to be directed carefully at the cancer and at the right dosage so it only kills the cancer cells without damaging too many normal cells.

Question 25

How are gamma rays used to sterilize medical instruments?

Answer 25

Gamma rays can sterilize medical instruments by killing all the microbes on the tools.

Question 26

What advantage is there to using gamma rays over boiling the instruments for sterilization?

Answer 26

Using Gamma Rays for sterilization is better than boiling the instruments because the instruments can be damaged by high temperatures.
The Gamma rays are also a strongly radioactive source that lasts a long time, so it doesn’t require replacing too often.

Question 27

What else can Gamma rays be used for besides sterilizing equipment or treating cancers?

Answer 27

Gamma radiation can be used to do non-destructive testing.

Question 28

What is an example of non destructive testing using Gamma rays?

Answer 28

Airline companies can check the turbine planes of their jet engines by directing gamma rays at them, if too much radiation gets through the blade to the detector on the other side, they know the blade’s cracked or there is a fault in the welding.