Radiation Safety Instruction for F- Praktikum · Radiation Safety Instruction for F- Praktikum ....
Transcript of Radiation Safety Instruction for F- Praktikum · Radiation Safety Instruction for F- Praktikum ....
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 Safety Instruction
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
Radiation Safety Instruction
Radioactive Radiation at FP _____________________________________________________________________________________________________________
radiation experiment energy ______________________________________________________________________________________________________
β,γ-radiation γ-Spektroskopie
Comptoneffekt
Koinzidenzmethoden Eg < 3 MeV
Aktivierungsanalyse
Höhenstrahlung
neutrons Aktivierungsanalyse En < 3 MeV
Radiation Safety Instruction
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
Radiation Safety Instruction
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
Radiation Safety Instruction
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
Radiation Safety Instruction
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
Radiation Safety Instruction
•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 Safety Instruction
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
Radiation Safety Instruction
Sealt radioactive sources
all radioactive sources in Praktikum are sealt no risk of incorporation do not damage sources
Radiation Safety Instruction
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 Safety Instruction
Radiation Protection Areas
Strahlenschutzverordnung
Röntgenverordnung
monitored area controlled area exclusion area
Radiation Safety Instruction
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 Safety Instruction
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 Safety Instruction
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
Radiation Safety Instruction
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)
Radiation Safety Instruction
Inverse Square Law
point source
1/16 4 times 1/9 3 times 1/4 2 times 1 1 dose distance
Radiation Safety Instruction
Crucial question: distance / exposure time
12
67
1011
89 3
12
45
12
67
1011
89 3
12
45
use tweezers
Radiation Safety Instruction
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