1. Background radiation and Uses of radiation

2. To Know the different sources of background radiation and uses of radiation
Progress
Explain why a certain radioactive isotope is chosen for a particular job.
To justify why a certain radioactive isotope is chosen for a particular job.
To explain what background radiation is.

3. To demonstrate good progress in this lesson
Name
Will…
Explain why a certain radioactive isotope is chosen for a particular job.
To justify why a certain radioactive isotope is chosen for a particular job.
To explain what background radiation is.
The Honley Learning Mindset Advocate for this lesson is…
Matthew – will show resilience by not giving up if he finds something difficult.

4. Engager Complete the following questions:
Compare alpha and beta radiation. [4]
Compare alpha and gamma radiation. [4]
The atomic number of thorium is 90. Use the periodic table to write a balanced decay equation for each of the decay of thorium-229 by alpha decay. [3]
The atomic number of thorium is 90. Use the periodic table to write a balanced decay equation for each of the decay of thorium-231 by beta decay. [3]
Describe and explain the difference between the decay equations in question 3, 4 and the decay equation for an isotope that decays by emitting gamma radiation. [2]

5. Self Marking Answers Check your work:
Both are emitted from the unstable nucleus of an atom. [1]
An alpha particle is a helium nucleus, but a beta particle is a fast moving electron.[1]
An alpha particle has a charge of +2, a beta particle has a charge of –1. [1]
An alpha particle is much more massive than a beta particle. [1]
An alpha particle is a particle; a gamma ray is an electromagnetic wave. [1]
An alpha particle has a charge of +2, gamma rays have no charge. [1]
An alpha particle is massive but gamma rays have no mass. [1]
[1] for top numbers, [1] for bottom numbers, [1] for symbols
The atomic masses and atomic numbers do not change [1] because there is no change to the element when atoms of it decay by gamma radiation. [1]

6. Sources of Background Radiation
What examples can you think of?
What examples can you think of?
Natural
Artificial

7. Natural sources

8. Artificial sources

9. What is Background Radiation?
Background radiation is all around us. We can do little to avoid it. Most background radiation comes from natural sources, while most artificial radiation comes from medical examinations, such as X-ray photographs.

10. How radiation is used
You should research
To diagnose illness
Radioactive tracers in medicine
To treat cancer
Radiotherapy
To find the age of archaeological specimens
Radiocarbon dating
Other non-medical uses
Measuring paper thickness, smoke detectors plus any others
Connector - Uses of radioactive sources you have 15 minutes
You should include:
How the different uses of radiation work.
Labelled diagrams to explain how the radiation is used.
The type of radiation that is used; i.e. alpha, beta or gamma.
Why this type of radiation is used.
The radioisotope that is used; i.e. uranium-235, americium-241
Why is this type of radioisotope used?
Half-life length, why is this important?
Details of the benefits and risks of using radioactivity.
Explanation of how the dangers can be minimised using safety precautions.
During the presentations you are to complete the following table:
Make sure you complete the table clearly as you need to know this information.
You can ask questions at the end if required.
We will evaluate each presentation, think about WWW and EBI.
Name of use
How it works
Radioisotope and type of emission
Why this type of emission is best?
Long or Short Half life? Why is this?
Safety Precautions taken

11. Have you covered the following information
You should include:
How the different uses of radiation work.
Labelled diagrams to explain how the radiation is used.
The type of radiation that is used; i.e. alpha, beta or gamma.
Why this type of radiation is used.
The radioisotope that is used; i.e. uranium-235, americium-241
Why is this type of radioisotope used?
Half-life length, why is this important?
Details of the benefits and risks of using radioactivity.
Explanation of how the dangers can be minimised using safety precautions.

12. Securing Activity - Complete the following tasks:
Explain how medical tracers work. Which types of ionising radiation can be used and why?
What is radiotherapy
Radiation from radioactive sources is used for different purposes. Identify the type of radiation you would use and give a reason for your choice:
Obtaining an image of an internal organ.
Finding out whether a kidney in a patient is blocked.
a) Explain why a radioactive isotope is used in a kidney scan should have a half-life that is not too short and not too long.
b) Evaluate whether this consideration is important for a temporary radioactive implant.
a) Write the ideal properties of a radioactive isotope used as a medical tracer.
b) When a radioactive tracer is used, explain why it is best to use a radioactive isotope that decays into a stable isotope.

13. Self Marking
A radioactive isotope is injected or swallowed and its progress around the body can be followed using an external radiation detector. A computer can produce an image from the detected radiation showing where the radiation is most concentrated. Gamma (or beta) emitters can be used as they can be detected outside the body.
Radiotherapy is the killing of cancer cells using high doses of radiation.
a) beta or gamma, can be detected outside the body.
b) gamma, radioactive source injected into patient to enter organ to be imaged so needs to do least damage whilst in body, gamma radiation passes through body tissue and detected using gamma camera.
a) Too short: radioactive isotope decays too much before scan is completed. Too long: patient exposed to ionising radiation unnecessarily.
b) Too long: after scan radioisotope needs to be stored for a long time until radioactivity is insignificant. Too short: radioactive isotope decays too much before scan is completed.
a) Emits radiation detectable outside the body, non-toxic, short half-life, decays into stable isotope.
b) Stable isotope in body is not dangerous, whereas unstable isotope is harmful as it emits ionising radiation harmful to the body.

14. 6 mark Question

15. Self Marking Up to 5 marks for any of the following points:
Both use radioactive materials
which emit radiation, usually gamma.
In the investigation of organs the source is inside the body, but in the control or destruction of tissue it is outside the body.
So in the investigation of organs the patient is contaminate, but in the control or destruction of tissue the patient is irradiated.
In the investigation of organs the source produces radiation (gamma) that is detected outside the body, but in the control or destruction of tissue the radiation is used to kill cells.
In the investigation of organs the source should have a relatively short half-life but in the control or destruction of tissue the half-life can be longer without affecting the patient.
Additional mark for correct spelling and grammar.

16. Work Sheets to print off

17. Non medical uses of radiation
When a radioactive substance is used, the substance must emit the appropriate type of radiation for that use.
Smoke alarms contain a radioactive isotope that sends out alpha particles into a gap in a circuit in the alarm. The alpha particles ionise the air in the gap so there is a current across the gap.
Why is alpha radiation used?
Automatic thickness monitoring in metal foil production uses a radioactive source that sends out beta radiation. The amount of beta radiation passing through the foil depends on the thickness of the foil. The rollers then adjust the thickness of the metal foil depending on the amount of radiation passing through the foil.
Why is beta radiation used?
A leak in an underground industrial pipe can be found by adding a radioactive tracer, emitting gamma, to the liquid in the pipe. A detector is moved along the ground above where the pipe is buried. The count rate will be found to increase where the pipe is leaking as a larger amount of liquid containing the radioactive tracer will collect there.
Why is gamma radiation used?

18. Medical uses of radioactive sources
Nuclear radiation is used in medicine to help doctors to diagnose internal disorders in patients and to treat disorders to make patients well again.
For each use, a radioactive isotope is needed that emits a specific type of radiation and has a suitable half-life.
Tracers
Radioactive tracers are used to trace the slow of a substance through an organ.
The tracer can be injected or ingested into the body.
An external detector then tracks the progress of the tracer through the body. A computer converts the readings from the detector to a display showing where the strongest readings arte coming from.
What type of radiation should be used? Why? What about the half-life length?

19. Medical uses of radioactive sources
Nuclear radiation is used in medicine to help doctors to diagnose internal disorders in patients and to treat disorders to make patients well again.
For each use, a radioactive isotope is needed that emits a specific type of radiation and has a suitable half-life.
Radiotherapy
Radiotherapy is the treatment of cancer using ionising radiation.
It can be used to control or kill cancer cells.
High doses of radiation will kill living cells, including cancer cells.
The radiation has to be directed carefully at just the right dosage so as to kill the cancer cells without damaging too many normal cells.
Radioactive implants can also be placed next to or inside the tumours.
What type of radiation should be used? Why? What about the half-life length?

20. Evaluating the risk
For every situation, it is worth considering both the benefits and the risks of using radioactive materials.
Tracers can be used to diagnose life-threatening conditions, while the risk of cancer from one use of a tracer is very small.
Whilst prolonged exposure to radiation poses risks and causes many side effects, many people with cancer choose to have radiotherapy as it may get rid of their cancer entirely. For them, the potential benefits outweigh the risks.
Perceived risk is how risky a person thinks something is. Its not the same as the actual risk of a procedure and the perceived risk can vary from person to person.