1 Radiation Protection
2 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!
3 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.
4 Units - Absorbed Dose D = Absorbed Energy / Mass = Δ W/m [J/kg] = [Gy] o 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 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 x10 9 ion pairs/cm 3 air; 1,6 x10 12 ion pairs/cm 3 water // absorbed energy 8,4x10-6 J/cm 3-1800 ion pairs/cell (size: 1000µm 3 ) // 225 ion pairs/nucleus (25µm 3 ) - 100 ionizations per cell (x-ray, γ- β- radiation) // 10.000 ionizations ( α, neutrons)
5 Biological effects of radiation source: SISS
6 Natural and anthropogenic radiation levels Natural radiation level: External component: - cosmic radiation (8 h transatlantic flight: 0.05mSv) 0.3 msv/a - terrestrial radiation (up to 1.5 msv/a in Black Forest region!): 0.4 msv/a Internal component: incorporated terrestrial nuclides: - Potassium 40 (z. B. milk) 0.3 msv/a - Radon (e.g. one year baby milk prepared with mineral water ->0.3mSv) 1.1 msv/a Source: SISS
7 Anthropogenic radiation level: - medicine (CT abdomen: up to 25mSv; radiography thorax: 0.1mSv) 2 msv/a - professional life 0.15 msv/a - nuclear facilities, research, Tschernobyl <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: 10 6 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
8 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
9 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
10 Locations Dose surveillance ( 35 RöV) through dosimeter and ring-dosimeter at the Siemens diffractometer (N110)!
11 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)
12 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
13 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
14 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 -12790 E26 Ralf.Meyer@wsi.tum.de Sonja Matich -12773 E24, E25, E26 Sonja.Matich2@wsi.tum.de After official hours: fire brigade -12024 oder -112