P3.3 Production, Uses And Risks Of Ionising Radiation From Radioactive Sources

Question 1

What are the properties of alpha radiation?

Answer 1

Slow and heavy
Strongly ionising
Not very penetrating
Is a helium nucleus

Question 2

What are the properties of beta radiation?

Answer 2

Light and fast
Moderately ionising
Moderately penetrating
Is an electron

Question 3

What are the properties of gamma radiation?

Answer 3

No mass, very fast
Weakly ionising
Very penetrating
Electromagnetic radiation

Question 4

What is a positron?

Answer 4

The antiparticle of an electron - it is like an electron but has a charge of +1

Question 5

What is neutron radiation?

Answer 5

When a substance emits neutrons. They can be more penetrating than gamma but not ionising directly. If an isotope absorbs a neutron, it can become radioactive

Question 6

What materials are used to stop neutron radiation?

Answer 6

Hydrogen rich materials

Question 7

What happens to isotopes below the stability curve?

Answer 7

They have too few neutrons to be stable, so they emit beta + decay, where a proton gets changed into a neutron.

Question 8

What happens to isotopes above the stability curve?

Answer 8

They have too many neutrons to be stable. They emit beta - decay, where a neutron changes into a proton.

Question 9

When does alpha decay occur?

Answer 9

Alpha decay occurs in elements that are too heavy to be stable, so the proton number decreases by two and the mass number by 4.

Question 10

When does gamma radiation occur?

Answer 10

When an isotope has too much energy. Gamma radiation always accompanies beta or alpha decay, it never occurs on its own.

Question 11

What ate quarks?

Answer 11

Smaller subatomic particles that make up protons and neutrons.

Question 12

What is an up quark?

Answer 12

A quark with a charge of 2/3.

Question 13

What is a down quark?

Answer 13

A quark with a charge of -2/3

Question 14

What quarks is a proton made of?

Answer 14

2 up quarks and a down quark

Question 15

What quarks is a neutron made of?

Answer 15

2 down quarks and an up quark.

Question 16

When a proton changes into a neutron, what happens?

Answer 16

An up quark changes into a down quark and a positron.

Question 17

When a neutron changes into a proton, what happens?

Answer 17

A down quark changes into an up quark and an electron is produced.

Question 18

What are tracers in medicine?

Answer 18

Tracers are radioactive isotopes with short half lives that a patient takes that, in the body, concentrates where a cancerous Tumor is present. It is used in diagnostics.

Question 19

How does PET scanning work?

Answer 19

A positron emitter is given to the patient. It concentrates where cancer is present and emits positrons. These collide with electrons in the body and annihilate, producing two gamma rays that go in opposite directions. These are picked up on by the PET scanner, and the cancer is positioned using triangulation.

Question 20

Why is developing new medical techniques controversial?

Answer 20

We don’t fully understand the long term benefits and side effects.

Question 21

What are the benefits of using radiation in hospitals?

Answer 21

You can diagnose and treat cancer

You can shrink tumours in palliative care.

Question 22

What are the risks of using radiation is hospitals?

Answer 22

Tissue damage
Cell mutation
Getting cancer

Question 23

Why do tracers need to have a short half life?

Answer 23

So that they don’t cause lasting damage to the patient