Radiation Safety Instruction for F- Praktikum · Radiation Safety Instruction for F- Praktikum . Contents Basics •Radiation •Activity •Dose definitions Radiation exposure •External

Radiation Safety Instruction

Radiation Safety Instruction for F-Praktikum

Contents Basics

•Radiation •Activity •Dose definitions

Radiation exposure •External radiation •Incorporation •Deterministic damages •Stochastic damages

Precautions •Radiation protection areas •ALARA, inverse square law •Shielding


Radiation

λ

β n

mass

ener

gy

electron positron keV – MeV

neutron 0.025eV...GeV

helium nucleus 4...6 MeV

γ α

11

12

13

14

15

16

17

18

f / Hz

-3

-4

-5

-6

-7

-8

-9

/ m

10

10 10

9 10

8 10

10 10

10

10

10

10

10

-10 10

-11 10

-12 10

10

-2 10

-1

0

10

10

10

10

10

10

10

10

19 10

20 10

21 10

“HR3” 89.3 MHz

microwave 2.45 GHz

X-ray tube(150 keV)

60 Co (1.3 MeV Quanta) γ

Visible light Ultraviolet

infrared


Radioactive Radiation at FP _____________________________________________________________________________________________________________

radiation experiment energy ______________________________________________________________________________________________________

β,γ-radiation γ-Spektroskopie

Comptoneffekt

Koinzidenzmethoden Eg < 3 MeV

Aktivierungsanalyse

Höhenstrahlung

neutrons Aktivierungsanalyse En < 3 MeV


Activity

Activity is a measure for the amount of radioactive material It indicates, how many nuclei will decay on average per second. Unit: 1 Becquerel, 1 Bq 1 s-1

no measure for hazard potential 0 200 400 600 800 1000

0.0

0.2

0.4

0.6

0.8

1.0

Zeit in Sekunden

mass in gramm

15 O 4.0 10 nuclei 22

2.3 10 Bq 20

1.4 10 nuclei 20

7.8 10 Bq 17


Dose Definitions

Energy dose DE •"physical quantity" DE = deposited energy per mass of your body, •unit 1 Gray, 1 Gy, 1 J/kg Equivalent dose H •taking into account risk •different kinds of radioactive radiation have a different effect on the human organism •energy dose is multiplied by weight acording to risk •weight has no unit H = wR •DE •unit: 1 Sievert, 1 Sv


Effective Dose / weights

wR radiation

20 alpha particles 20 heavy ions

10 n, 10 keV < E < 100 keV 20 n, 100 keV < E < 2 MeV

5 protons E > 5 MeV 10 n, 2 MeV < E < 20 MeV

5 neutrons, E < 10 keV 1 electrons 1 photons wT tissue

0.12 colon 0.01 skin

0.12 lung 0.05 thyroid gland 0.05 bladder

0.12 bone marrow 0.05 chest 0.20 gonads

effective dose: Eeff = ΣR,T wR • wT • DT,R

DT,R : energy dose in organ or tissue T by radiation component R wT : weight for organ or tissue T ΣwT= 1 wR : weight for radiation component R


Overview Dose Definitions

energy dose deposited energy per mass

of your body

equivalent dose takes into account

different biological effectivness of different kinds of radiation

effective dose takes into account different

sensibility of different organs or tissue

multiplication by weight for radiation

multiplication by weight for

tissue


•not occupationally exposed to radiation: 1 mSv •Praktikum: 1mSv (typical dose per experiment 1-10 µSv) no experiments with radioactivity during pregnancy •occupationally exposed to radiation

•workers category A: 20 mSv ( medical checkup every year )

•workers category B: 6 mSv ( usually no medical checkup )

•under age: 1 mSv •pregnancy : 1 mSv (for unborn child during pregnancy)

•whole working life: 400 mSv

Effective Dose Limits per Year:


Radiation Exposure in Germany

exposure on average per year: about 4.1 mSv •natural sources about 2.1 mSv

•cosmic rays: 0.3 mSv •terrestrial radiation: 0.4 mSv •internal exposure: 1.4 mSv ( 40K , 222Rn, 220Rn)

•man-made sources about 2.0 mSv •medicine 2.0 mSv •industry 0.01 mSv •Tschernobyl 0.01 mSv •test of nuclear wappons 0.005 mSv •travel with airplanes 0.005 mSv •occupation 0.002 mSv •nuclear power plants 0.001 mSv


Different Kinds of Exposure

external radiation

incorporation


Sealt radioactive sources

all radioactive sources in Praktikum are sealt no risk of incorporation do not damage sources


Radiation Exposure

External exposure •natural radioactivity

•cosmic rays ( γ, e-, neutrons, muons, sec. protons ) •terrestrial radiation ( decay chain 232Th, 238U, 235U => inhal. of radon , 40K )

•man-made radiation

•X-rays ( e.g. doctor, cavities, clystrons ) •gamma radiation ( gamma sources, activation ) •beta radiation ( beta sources ) •neutrons ( particle accelerator, neutron source )

monitoring at Praktikum with •electronic dosemeter

TLD Albedo Personendosimeter


Radiation Protection Areas

Strahlenschutzverordnung

Röntgenverordnung

monitored area controlled area exclusion area


Radiation Exposure III

Deterministic Damages •above a certain threshold (250 mSv) a damage certainly occurs •severity of damage depends on dose

examples: reddened skin (burn), changes in blood count, sickness


Radiation Exposure III

Deterministic Damages •above a certain threshold (250 mSv) a damage certainly occurs •severity of damage depends on dose

examples: reddened skin (burn), changes in blood count, sickness after 3 days after 10 days

192Ir-source for 6h in trouser pocket (100Gy)


Radiation Exposure IV

Stochastic Damages •probability for a damage proportional to dose •no threshold •severity of damage independent from dose per 200 mSv exposition the risk to die from cancer increases by 1% examples: leukaemia, cancer


Precausions

rules for expose to radioactivity •avoid unnecessary exposure •ALARA principle "As Low As Reasonably Achievable" •general rules

• maximise distance from source • minimise exposure time • use shielding (do not remove shielding)


Inverse Square Law

point source

1/16 4 times 1/9 3 times 1/4 2 times 1 1 dose distance


Crucial question: distance / exposure time

12

67

1011

89 3

12

45

12

67

1011

89 3

12

45

use tweezers


At Praktikum: instruction by assistant obey instructions wear dosemeter (note dose value) read radiation protection directive

do not eat or drink in rooms with radioactive sources

wash your hands afterwards

Precausions


Thanks for your attention!

Radiation Safety Instruction for F- Praktikum · Radiation Safety Instruction for F- Praktikum . Contents Basics •Radiation •Activity •Dose definitions Radiation exposure •External

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