Radiation Protection

Strahlenschutzbelehrung – Allgemeiner Teil Radiation Protection
1 Strahlenschutzbelehrung – Allgemeiner Teil Why radiation protection?
- Ionizing radiation (>5eV -> UV; X-rays;α,β,γ-radiation)has physical, chemical and
biological effects -> human tissue (70% water!) and genetic material can be damaged or
destroyed.
source SISS; radiation damage after alignment of a diffractometer
Risk potential must be taken seriously, especially because we don´t have any “natural”
senses to detect radiation!
2 Strahlenschutzbelehrung – Allgemeiner Teil In order to protect human beings and the environment -> legislative body enacted the
“Atomic Law”
o Nuclear energy (U235, U238, Th232)
o All other forms of radiation ->
 Radiation protection ordinance: artificial and natural radioactivity; irradiated nuclear
fuel; operation of equipment to produce ionizing radiation and sources of stray
radiation >1MeV (->plasma equipment; ion accelerators, etc.)
 X-ray ordinance: x-ray apparatus or source of stray radiation with an energy
between 5keV – 1MeV.
3 Strahlenschutzbelehrung – Allgemeiner Teil Units
- Absorbed Dose D = Absorbed Energy / Mass = Δ W/m [J/kg] = [Gy]
-
o
Organ Dose (Sv): depends on what kind of radiation:
 q = 1 photons (all energies -> γ-, x-rays); electrons (-> β-radiation)
 q = 10 neutrons (2-20MeV); 20 (100keV-2MeV)
 q = 20 α-radiation
o
Effektive Dose (Sv): depends on sensitivity of irradiated organ:
 W = 0.12 bone marrow, intestine, lungs, stomach
 W = 0.04 thyroid
 W = 0.01 bones, skin, liver
Equivalent Dose = Q × N × D; [J/kg] = [Sv] (ICRU standardized soft tissue)
Q = weighting factor ( w R radiation, w T tissue); N = 1 (for external radiation; incorporated: governmentally defined);
- Body Dose = collective term for Organ Dose and Effective Dose
- Personal Dose = Equivalent Dose, measured with ministerial dosimeter
- Local Dose = Equivalent Dose, measured at a certain place
- Local dose rate (ODL) = Local Dose / Time [Sv/h]
e. g. 10mSv in matter causes:
- 2,0 x109 ion pairs/cm3 air; 1,6 x1012 ion pairs/cm3 water // absorbed energy 8,4x10-6 J/cm3
- 1800 ion pairs/cell (size: 1000µm3) // 225 ion pairs/nucleus (25µm3)
- 100 ionizations per cell (x-ray, γ- β- radiation) // 10.000 ionizations ( α, neutrons)
4 Strahlenschutzbelehrung – Allgemeiner Teil Biological effects of radiation
source: SISS
5 Strahlenschutzbelehrung – Allgemeiner Teil Natural and anthropogenic radiation levels
Natural radiation level:
External component: - cosmic radiation (8 h transatlantic flight: 0.05mSv)
- terrestrial radiation (up to 1.5 mSv/a in Black Forest region!):
0.3 mSv/a
0.4 mSv/a
Internal component: incorporated terrestrial nuclides:
- Potassium40 (z. B. milk)
- Radon (e.g. one year baby milk prepared with mineral water ->0.3mSv)
Source: SISS
0.3 mSv/a
1.1 mSv/a
6 Strahlenschutzbelehrung – Allgemeiner Teil Anthropogenic radiation level:
- medicine (CT abdomen: up to 25mSv; radiography thorax: 0.1mSv)
- professional life
- nuclear facilities, research, Tschernobyl
2 mSv/a
0.15 mSv/a
<0.01 mSv/a
source: SISS
 Average level of radiation: natural sources: 2.1 mSv/a; anthropogenic sources: 2.1 mSv/a
 Lethal dose for human beings: 4000 mSv (sheep: 1000mSv ; wasp: 106 mSv )
 Comparable death risks - equivalent to one thorax radiography = eat 100 grilled steaks = live for two days
in New York = smoke one cigarette = live for 150 years close (<30km) to a nuclear power plant
7 Strahlenschutzbelehrung – Allgemeiner Teil Characterization of radiation protection areas
source: SISS
 People who are professionally exposed to radiation may accumulate 20mSv/a (= 20mSv in just one day,
rest of the year nothing = 1mSv within 20 days, rest of the year nothing; or…).
 Women of child-bearing-age: max. 2 mSv in a month (never 20mSv in just one day!)
 Professional lifetime dose: 400mSv
8 Strahlenschutzbelehrung – Allgemeiner Teil X-ray apparatus at the WSI
-
Source of stray radiation: equipment which produces x-rays, but the originating radiation is NOT used (SEM, RHEED;
e-beam evaporation etc.). Their operation DOESN´T require permission (-> mind indication labels), if:
 U<30kV // ODL < 1µSv/h
 U<30kV // design approval
 U>40kV // ODL < 1µSv/h (-> TV)
o in many laboratories; even if they don´t require permission, they have to be reported to the radiation
protection officer (SSB)
- X-ray apparatus:
o E 25:
 N104: Diffractometer – inherent protection: cage covers the source of radiation and the sample
completely (during sample alignment and operation); ODL <7.5µS/h; two separate safety
arrangements; design approval. Radiation level <0.1µSv/h
 N202: XPS: operates only in vacuum; Ar-ion-source. Radiation level <0.15µSv/h
o E 26:
 N110: Diffractometer Siemens: NO inherent protection – alignment only possible with open
path of rays -> always use dosimeter, ring-dosimeter (even if you are 100% sure that the
shutter is closed!!!), lead-glove, close-off the back part of the lab N 110 with provided plate!!!
Radiation level: up to 100µSv/h
 N110: Diffractometer Stoe: inherent protection. Radiation level <0.1µSv/h
9 Strahlenschutzbelehrung – Allgemeiner Teil Locations
Dose surveillance (§35 RöV) through dosimeter and ring-dosimeter at the Siemens diffractometer
(N110)!
10 Strahlenschutzbelehrung – Allgemeiner Teil General rules
- Each x-ray apparatus and source of stray radiation must be labeled as such and may only be used by
appropriately trained personnel.
- These persons must read up on the x-ray ordinance themselves (www.siss.tu-muenchen.de; respectively
see copy next to the x-ray apparatus)
- Persons under age 18 and pregnant women are not allowed to operate or remain close to any x-ray
apparatus
- When working with radiation eating, drinking and smoking is forbidden (general lab rule)
11 Strahlenschutzbelehrung – Allgemeiner Teil The 4-A-Rule
- Abstand halten
keep your distance
- Aufenthaltszeit minimieren
minimize time of exposure
- Abschirmung verwenden
use protection – gloves, dosimeter…
- Aktivität (Intensität) verringern
minimize activiy / intensity
- (Andere machen lassen)…
let others do it – sometimes they are more experienced and can
do the work more safely
12 Strahlenschutzbelehrung – Allgemeiner Teil Rules that should never be forgotten
- No radioactivity at the WSI !
- Rebuilding or reconstruction of an x-ray apparatus / source of stray radiation (especially
security installations) is strictly forbidden! Always contact SSB
- If necessary – wear protective clothing and dosimeter!
- If accidental irradiation should occur – always contact SSB immediately!
- XPS and especially diffractometer (E26 – Siemens) may not be operated if no SSB is present
at the WSI (or reachable within 15 min).
- Pregnancies are to be reported immediately (SSB)
- Each relocation and / or new acquisition of equipment that produces ionizing radiation has
to be reported to the SSB
13 Strahlenschutzbelehrung – Allgemeiner Teil Who can I contact?
Radiation protection supervisor (§ 13 RöV):
Kanzler der TU München
Chief representative
„Sicherheit und Strahlenschutz (SISS)“:
Dr. Heinz G. Daake
(Tel: -14688)
Radiation protection enigneer (TUM):
Peter Sabath (SISS)
(Tel: -14680)
Company medical officer:
Dr. Lueg-Müller
(Tel: -14000)
At the WSI:
Radiation protection supervisor = managing director: Prof. Stutzmann or Prof. Abstreiter
Radiation protection officer:
Name / chair
phone.
mail
____________________________________________________________________________
Ralf Meyer
E26
Sonja Matich
E24, E25, E26
-12790
[email protected]
-12773
After official hours: fire brigade -12024 oder -112
[email protected]
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