PowerPointPrsentation

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General Radiation Protection Instructions

• Content
• Basics
• radiation
• activity
• dose
• Radiation exposure
• external exposures
• incorporation
• deterministic harm
• stochastic harm
• Protection measures, personal safeguards
• arrangements in workplaces
• ALARA, inverse square law
• shielding
• contaminations
• Video operation of the GSI access control system
• Contact

Torsten Radon Tel. 2400 Fax. 2109 email
T.Radon_at_gsi.de
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Radiation "transport of energy"
Photon
b
a
N
n / Hz
Electron Positron keV MeV
Neutron at GSI 0.025eV...2GeV
Helium nucleus 4...6 MeV
Energy
Mass
l / m
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Activity
Activity is a measure for the quantity of a
radioactive substance It is the number of
atomic nuclei of a substance decaying per
second Unit 1 Becquerel, 1 Bq 1 s-1
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Dose
Matter is mutated by ionising radiation A
quantitative measure for these mutations is given
by dose terms Dose values provide assessments
of hazards Which dose term applies for which
question?
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Terms of Dose

• absorbed dose DE
• DE dE/dm, energy per mass,
• unit 1 Gray, 1 J/kg, 1 Gy
• equivalent dose H
• used to describe a risk for the human body
• takes into account the effect of different kinds
• of radiation on the human body
• absorbed dose is multiplied by a weighting-factor
• H q DE
• unit 1 Sievert, 1 Sv

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Effective dose / weighting factors
effective dose Eeff SR,T wR wT DT,R
(also used for risk assessment)
DT,R absorbed dose in body part or tissue T by
external radiation of type R wT tissue
weighting factor for body part or tissue T
SwT 1 wR radiation weighting factor for type
of radiation R
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Occupationally exposed people

• Annual dose limits for effective dose
• limit for members of the public 1 mSv
• occupational radiation exposure
• Category A 20 mSv (
  annual medical examination, before start )
• Category B 6 mSv
• adolescents 1 mSV
• occupational life dose 400 mSv
• annual limits for doses of body parts for
  special groups of workers

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Radiation exposure

• External exposure
• natural sources of radiation
• cosmic radiation ( g, e-, neutrons, mesons,
  secondary protons )
• terrestrial radiation ( 232Th, 238U, 235U gt
  inhalation of Radon , 40K )
• artificial sources of radiation
• X-rays ( e.g. in medicine, cavities, klystrons,
  )
• gamma radiation (gamma source, particle
  accelerators )
• beta radiation ( beta sources )
• neutron radiation ( particle accelerator,
  neutron source )
• Surveillance of external exposure with
• personal dosimeters
• (dose reading every month _at_ GSI, external
  analysis)
• measurement of the local dose(-rate)

TLD albedo personal dosimeter
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Radiation Exposure II

• Incorporation
• Inhalation
• ( Breathing in of a radioactive
• substance )
• Ingestion
• ( Swallowing of a radioactive
• substance )
• via wounds
• via (unwounded) skin

Daten vom Bundesamt für Strahlenschutz BFS
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Radiation exposure III

• Deterministic harm
• Occurrence of a harm above a certain threshold
• cruelty of the harm is dependent on the dose
• dose rate plays an important role
• Examples
• Changes of the skin, changes of the blood count,
  sickness
• threshold for deterministic harm for (bodypart-)
  doses gt 250 mSv

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Radiation Exposure IV

• Stochastic harm
• probability for the appearance of harm
• is dependent on the dose
• no threshold
• the cruelty of harm is independent from the dose
• dose rate plays usaually no role
• examples
• leukemia, cancer, hereditary harms
• stochastic harms are caused by changes of
  inherited materials in the cells

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Radiation exposure in Germany

• Mean total exposition per year 4.1 mSv
• natural sources of radiation 2.1 mSv
• cosmic irradiation 0.3 mSv
• terrestric irradiation 0.4 mSv
• internal irradiation 1.4 mSv ( 40K , 222Rn,
  220Rn)
• artificial sources of radiation 2.0 mSv
• medicine 2.0 mSv
• industry 0.01 mSv
• Tschernobyl 0.01 mSv
• tests of nuclear weapons 0.005 mSv
• air travel 0.005 mSv
• profession 0.002 mSv
• fossile Energieträger 0.002 mSv
• nuclear power plants 0.001 mSv
• industry products 0.001 mSv

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Classification and Delineation of Areas
Supervised Area Dyear gt 1 mSv Controlled Area
Dyear gt 6 mSv Inaccessible Area dose rate gt 3
mSv/hour duration of stay 2000 hours per year
( 50 weeks 40 hours / week )
Zutritt verboten Strahlung Sperrbereich
Do not cross barriers ! (cordons, barrier tapes,
caution labels)
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Radioactivity at GSI / Examples
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Safeguards

• Basic rules for handling of ionising radiation
• avoid needless expositions with ionising
  radiation
• ALARA principle "As Low As Reasonably
  Achievable"
• Three basic measures
• keep distance
• limit your duration of stay
• use shielding

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Inverse Square Law
point source

• valid only for point sources
• (dimension of the source is
• small compared to the
• distance to the source)
• for large dimensions
• dose 1/distance
• valid for all types of radiation

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"Gretchen" question distance versus duration
a)
b)
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Radiation Shielding

• g-radiation e.g. 60Co (1.3 MeV) 40K (1.5 MeV
  )
• shielding material with high atomic number
• lead, copper,..
• b-radiation e.g. 90Sr (0.55 MeV) 32P (1.7 MeV)
  14C (0.16 MeV)
• range in water 1cm
• shielding material acrylic glass, aluminium (low
  atomic numbers)
• shielding material with high atomic number causes
  Bremsstrahlung
• a-radiation e.g. 222Rn (5.5 MeV), 252Cf (6.1
  MeV)
• range in air few centimeters
• range in matter few hundredth of a millimeter
• neutron radiation produced in nuclear reactions
• tenth layer in concrete 1m
• shielding with high content of hydrogen (acrylic
  glass, concrete)

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Contamination "Pollution with radioactive
substances"

• usually not bonded gt "risk of dissemination"
• contamination means risk of incorporation
• Precautions
• no drinking
• no eating
• no smoking
• no painting of the face (make up)
• no access with open wounds
• protection clothing if necessary (gloves,
  overalls, respiratory masks ...)
• no dissemination
• Decontamination
• clean from the outside to the inside
• control of decontamination success with
  appropriate devices
• decontamination or disposal of tools

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Disposal of radioactive residuals
Planning Before accomplishing activities possibly
resulting in radioactive residuals -gt inform the
safety and radiation protection department (SiSt)
Consultations in separation, labelling, and
collection of residuals Separating, Labelling,
Collecting Separate residuals, label orderly and
collect safely Handing over Announcement of the
disposal for radioactive residuals at the
department for safety and radiation protection
special form called interner Begleitschein für
radioaktive Reststoffe www.gsi.de -gt
Informationen -gt Info der Abteilungen -gt
Sicherheit und Strahlenschutz -gt Formulare zum
Ausdrucken Contact person in charge of
radioactive residuals J.Lindenberg_at_gsi.de
Tel. 2400, email J.Lindenberg_at_gsi.de or
radiation protection officer on duty beeper 12
5291 XXXX
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Access control system
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Contact to the department for safety and radiaton

experiments, booth system rad-prot-officer on
shift PSA 12 5291 XXXX radioactive
residuals J. Lindenberg Tel. 1381 external
companies, radioactive transports A.
Knapp Tel. 2414 radioactive sources Herr
Lehmann Tel. 2455, 2471 laser-safety
rad.prot. delegate of SIS T. Radon Tel. 2400
operational radiaton protection rad.prot.
delegate of UNLIAC Ch. Pöppe Tel.
1382 industrial safety D. Plazura-Olszowski Tel
. 2700 A. Niermeyer Tel. 2700 head of
department G. Fehrenbacher Tel. 2007