RADIOACTIVE Sheryl Hoffmann shoffmannconcordia sa edu au Updated

RADIOACTIVE! Sheryl Hoffmann shoffmann@concordia. sa. edu. au Updated 2020

SUMMARY Legislation ARPNSA Safety Guide Australian Curriculum Theory Practicals for middle school students Practicals for senior school students

SA LEGISLATION Radiation Protection and Control Act 1982 Radiation Protection and Control (Ionising Radiation) Regulations 2015 (SA) § Part 6—Miscellaneous Division 1—Use of ionising radiation in schools 191—Interpretation (1) In this Division— the Code means “the Code of Practice for the Safe Use of Ionizing Radiation in Secondary Schools” (1986) published by the National Health and Medical Research Council,

THE CODE

SA LEGISLATION 192—Use of radioactive substance etc in secondary school to be in accordance with Code (1) The use of a radioactive substance or apparatus in a secondary school must be in accordance with the Code. (2) A person in charge of a secondary school must ensure that at all times there is a person designated to act as the responsible teacher for the purposes of compliance with the Code. (3) If this regulation is not complied with, the person in charge of the school is guilty of an offence.

GUIDELINES

AUSTRALIAN CURRICULUM Science Year 9 Science Understanding / Chemical sciences Content description All matter is made of atoms which are composed of protons, neutrons and electrons; natural radioactivity arises from the decay of nuclei in atoms

AUSTRALIAN CURRICULUM Elaborations • describing and modelling the structure of atoms in terms of the nucleus, protons, neutrons and electrons • comparing the mass and charge of protons, neutrons and electrons • describing in simple terms how alpha and beta particles and gamma radiation are released from unstable atoms

AUSTRALIAN CURRICULUM Achievement Standard By the end of Year 9, students explain chemical processes and natural radioactivity in terms of atoms and energy transfers and describe examples of important chemical reactions.

WHAT IS RADIATION?

IONIZING RADIATION Ionizing radiation has enough energy to cause chemical changes by breaking chemical bonds The energy is absorbed by the surroundings This can cause damage to living tissue

3 KINDS OF IONIZING RADIATION Alpha particles – which include two protons & two neutrons Beta particles – which are essentially electrons Gamma Rays & X-Rays – which are pure energy (photons)

MEASURING RADIATION Two measurements: Activity Exposure

ACTIVITY How much radiation is coming out of something Unit: Becquerel (Bq). The Becquerel counts how many particles or photons (in the case of wave radiation) are emitted per second by a source. 1 Bq = 1 disintegration per second (a very small unit).

EXPOSURE Measures the effects of that radiation on anything that absorbs it Units: Sievert (Sv) & milli. Sievert (m. Sv)

EXPOSURE There are three ways to express radiation exposure: Absorbed dose: the energy 'deposited' in a kilogram of a substance by a radiation source; measured in an international (SI) unit called the Gray (Gy). Equivalent dose: relates the absorbed dose to the biological damage of the type of radiation. The absorbed dose is multiplied by radiation weighting factor (w. R); measured in an international (SI) unit called the Sievert (Sv). Effective dose: the equivalent dose multiplied by tissue weighting factor (w. T) for the different harmful effects of radiation on different types of tissue. If more than one organ has been exposed, the overall effective dose is the sum of all the effective doses of all the exposed organs. The unit of effective dose is the Sievert (Sv).

ACTIVITY & DOSE

EXPOSURE Source of Exposure General Australian background radiation 1. 5 m. Sv per year Natural radiation at sea level in 0. 36 m. Sv per year Australia (cosmic) Chest X-ray 0. 02 m. Sv 7 hour flight 0. 05 m. Sv Domestic airline pilot 2 - 6 m. Sv per year Max occupational exposure allowed 20 m. Sv (full body) Max public exposure allowed 1 m. Sv Standard School demo 0. 01 m. Sv (to teacher’s hand)

ADMINISTRATIVE PROCEDURES 1. Appoint a Radiation Supervisor 2. Local Rules (see Annex 4) 3. Risk Assessment (see Annex 3) 4. Staff Induction 5. Students Age 6. Record Keeping 7. Storage 8. Disposal 9. Spills 10. Inspection & Wipe Test (Annex 5)

WIPE TEST (ANNEX 5) Fold a clean, dry, paper tissue to make a small pad with an area about the size of the window of the radiation detector. Hold the tissue in forceps and gently wipe the pad over the surfaces of the source Hold the radiation detector very close to, but not touching, the wiping surface of the tissue. Count the radioactivity on the tissue for 2 minutes If the count from the tissue is less than 1. 5 times background, the source has passed the wipe test

JUNIOR PRACTICALS 1. WHAT ITEMS ARE RADIOACTIVE? 2. BACKGROUND RADIATION 3. TIME AND RADIATION EXPOSURE 4. DISTANCE AND RADIATION EXPOSURE 5. SHIELDING

RADIATION IN THE HOME

BACKGROUND RADIATION

REDUCE TIME & REDUCE EXPOSURE Is it safe to wear this watch for 8 hours per day?

VASELINE GLASSWARE How long is it safe to sit 3 m from this item?

INVERSE SQUARE LAW Intensity α 1 ----------(distance ) 2

SHIELDING

SHIELDING

SENIOR PRACTICALS Cloud Chamber Smoke Detector Half-life Experiments §Protactinium Generator §Thoron Generator §Balloon §Caesium /Barium Generator

CLOUD CHAMBER

SMOKE DETECTOR

INSIDE A SMOKE DETECTOR

HOW A SMOKE DETECTOR WORKS The alpha particles pass between the two charged metal plates, causing air particles to ionise (split into positive and negative ions). The ions are attracted to the oppositely charged metal plates causing a current to flow. When smoke enters between the plates, some of the alpha particles are absorbed causing less ionisation to take place. This means a smaller than normal current flows so the alarm sounds.

URANIUM DECAY CHAIN

PROTACTINIUM GENERATOR

PASCO ISOTOPE GENERATOR KIT (BARIUM-137 m)

THORON GENERATOR

BALLOON

HALF-LIFE

REFERENCES NSW Chemical Safety in Schools Wikipedia http: //www. ansto. gov. au/ http: //www. arpansa. gov. au/ http: //www. bbc. co. uk/schools/gcsebitesize/science /add_ocr_gateway/radiation/radioisotopesrev 3. shtm l http: //www. pasco. com/prod. Catalog/SN/SN 7995_isotope-generator-kit-barium-137 -m/index. cfm Practical work using low-level radioactive materials available to the public, Ralph Whitcher, SSR June 2011, 92(341) 65

COPY OF THIS POWERPOINT http: //sherylhoffmann. weebly. com/

CREATIVE COMMONS Creative Commons This copyright work is licensed under a Creative Commons Attribution-Noncommercial 3. 0 Australia licence. To view a copy of this licence, visit http: //creativecommons. org/licenses/by-nc/3. 0/au/ In essence, you are free to copy, communicate and adapt the work for non-commercial purposes, as long as you attribute the work to Sheryl Hoffmann and abide by the other licence terms. Contact information: Sheryl Hoffmann Phone: +61 8 8291 9325 Fax: +61 8 8272 1463 Email: shoffmann@conconcordia. sa. edu. au