Airport Airport Airport Airport SecuritySecuritySecuritySecurity ScreeningScreeningScreeningScreening DevicesDevicesDevicesDevices

Dr. rer.nat. Christian FeltenBGFInstitution for statutory accident insurance and prevention in the vehicle operating tradesHamburg, Germany

PossiblePossiblePossiblePossible Health Health Health Health HazardsHazardsHazardsHazards duedueduedue to to to to ScreeningScreeningScreeningScreening????

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Contents

■ Physics

■ Effects on People

■ Limiting Values

■ Technologies

■ Physics

■ Effects on People

■ Limiting Values

■ Technologies

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EMI

X-rays

Airport security screening devices to detect explosives or metal

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Overview:

Frequencies & Wavelengths

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Physical Units & Dimensions (Low Frequency LF)

Variable Sign Unit induced by

Electric field strength E [V/m] voltage

Example: capacitor

Magnetic field intensity H [A/m] current

Example: magnetic coil

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Electromagnetic induction B Tesla [T = Vs/m²]

B = µ • H

Magnetic permeability µ Henry/m [H/m]

in air: µ = 1.257 H/m

Physical Units & Dimensions (LF)

Electric current causes a magnetic field. The effect of the field on media is calledelectromagnetic induction.

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Electromagnetic induction B Tesla [T = Vs/m²]

B = µ • H

Magnetic permeability µ Henry/m [H/m]

in air: µ = 1.257 H/m

Physical Units & Dimensions (LF)

Electric current causes a magnetic field. The effect of the field on media is calledelectromagnetic induction.

This is what we need

for personnel

security system

scanners

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Predominant Fields

Conditions Example Pred. Field

low frequency (<30 kHz) high voltage electric

high voltage power line

low current

low frequency (<30 kHz) passengerpassengerpassengerpassenger screeningscreeningscreeningscreening, magnetic

low voltage electric motors,

high current transformers

high frequency (>30 kHz) radar, microwaves, electro-magnetic

radio (coupled)

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Effects on People, EMI

Low Frequency LFLow Frequency LFLow Frequency LFLow Frequency LF

■ Stimulus of muscle-, nerve- and sense-cells (definite threshold)

■ Hairvibration >5 kV/m

■ Scintillation of eyes >5 mT (50 Hz)(magnetophosphenes)

High Frequency HFHigh Frequency HFHigh Frequency HFHigh Frequency HF

■ Warming of the body(possibly deep:bypass of the receptors of skin)

critical: eyes, ankles, patella, testes and metallic implants

•Influence on cardiac pacemakers

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Effects on PeopleNonNonNonNon----thermicthermicthermicthermic EffectsEffectsEffectsEffects of High of High of High of High FrequencyFrequencyFrequencyFrequency

■ Influence on brain-activities

■ Interaction with cells/cell membranes

■ Variation of immune system or hormone parameters

■ Effect on blood-brain barrier

Conclusion:

There are little non-thermic effects, but there is no evidence for adverse effects

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Effects on People, EMI

Yes?

■ Some (weak) hints fromepidemiology

■ Non-thermic effectswithout interpretation

No?

■ No accumulated dose

■ No mechanism of cancerogenesis known

■ If at all there are only a fewcase numbers

Cancerogenesis by EMI?

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Exposure Area 1: what does it mean?

Not: implication of danger, particularly with regard to shortterm exposure

Required: safety instructionsand documentation (BGV B11)

Danger Zonepers. Schutz-ausrüstungen

Area of higherExposure

Exposure Area 1

Expousre Area 2

Gefahrenbereich

Kurzbereich2h

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Examples for Reference Values, ICNIRP, Public Exposure

High Frequency Immissions

frequency (f) electric field strength magnetic field strength

(MHz) (V/m) (A/m)

100: FM Radio 28 0,073

900: Mobile (D-Net) 41,25 0,111

2450: Microwave oven 61 0,16

Low Frequency Immissions

frequency (f) electric field strength magnetic induction

(Hz) (kV/m) (µT)

50: Home appliances 5 100

3-6 kHz: Screening 0,087 6,25

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Examples for Limiting Values → BGV B 11 (occupational)

High Frequency Immissions

frequency (f) electric field strength magnetic field strength

(MHz) (V/m) (A/m)

100: FM Radio 27,5/61,4* 0,073/0,163*

900: Mobile (D-Net) 41,25/92,1* 0,109/0,244*

2450: Microwave oven 61,5/137,3* 0,163/0,364*

Low Frequency Immissions

frequency (f) electric field strength magnetic induction

(Hz) (kV/m) (µT)

50: Home appliances 6,67/21,32* 424/1358*

3-6 kHz: Screening 0,333/1,066* 21,22/67,9*

*Exposure area 2/1

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Example: C.E.I.A. S.p.A. Italy, Type 02PN10

in Germany offered by Heimann

♦Frequency 3-6 kHz (LF)

♦we need data of the electro-magnetic induction (Tesla)

(measured value and limiting value)

Air Passenger Security Screening System I

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Air Passenger Security Screening System II

■ Measurement by„Austrian Research Centers Seibersdorf“ 2001:

■ <1,5 µT: side of the receiver

■ ≤6,0 µT: in the middle

■ max. 58,6 µT: side of the emitter in 40 cm height

■ Limiting value (BGV B11):21,22 µT (Area 2)67,90 µT (Area 1), 169,75 µT for legs and arms

And: very short time of exposure

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Air Passenger Security Screening System III

Result:

■ There is definitely no risk for members of staff or passengers incl. pregnant women orchildren

■ There is no risk by repeated crossing of thescanners

■ An influence on old or bad CardiacPacemakers is nervertheless possible:

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What are potential EMI Hazards due to Screening?

• People with cardiac pacemakers or other „activebody adjuvants“

(possible interferencesalready inexposure area 2)

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X-Rays

AnotherAnotherAnotherAnother typetypetypetype of of of of physicsphysicsphysicsphysics…………

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Physical Units & Dimensions (X-rays)

■ X-rays are Ionizing Radiation!

■ Absorbed dose D [Gy] – in standardised tissue

■ Equivalent dose H [Sv]

D • Q = H

Radiation quality factor Q (α = 20 / β, γ, X-ray = 1)

■ Equivalent dose rate [Sv/h]

■ Effective dose E [Sv]

E = Σ wi • Hi

Tissue weighting factor w for every organ

■ Local dose H*(10) [Sv]

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Possible Effects on People, X-rays

■ X-rays are Ionizing Radiation!

■ High (cumulative) doses may cause cancer

■ Very high doses may cause erythema or lossof hair

This requires the main guideline of radiation protection: on principle ALARA: „as low as reasonably achievable“

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X-rays: Limiting Values

■ ICRP-Guidelines, in Germany RöV:

■ effective Dose ≤ 20 mSv/a for people withoccupational radiation exposure,

■ and ≤ 1 mSv/a for public

■ (and some more details)

ICRP = International Commission on Radiological Protection

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Luggage Inspection, Systems for carry-on Luggage

■ Employees nearby the X-ray unit:approx. 192 µSv/a [equivalent dose rate]

■ Interior space, one passage:0,5 - 2,1 µSv [local dose]

■ 10 cm from the surface:≤ 0,3 µSv/h [local dose rate]

■ in front of lead lamella:≤ 1,0 µSv/h [local dose rate]

Measurement (1991 - 2001):TÜV and Administration of Occupational Safety Hessen,several HEIMANN-Systems with X-Ray Photograph

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Systems for Suitcases and other checked Luggage

e.ge.ge.ge.g. . . . HeimannHeimannHeimannHeimann HiHiHiHi----ScanScanScanScan SystemSystemSystemSystem

5 cm distance from surface(all around): < 0,1 µSv/h

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For Comparison

■ Employees nearby the X-ray unit:approx. 192 µSv/a = 0,192

mSv/a

■ Radiography of teeth: approx. 0,1 mSvRadiography of lumbar spine: approx. 5 mSv

■ Average natural background radiation in Germany: 2,5

mSv/a

■ Limiting value (public): 1 mSv/a

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Detection of Critical Components of Luggage

■ Visual■ Dogs■ Metal detection■ Neutron Activation■ Trace detectors (gas-chromatography, spectroscopy)■ Check of density■ X-ray diffraction for identification of substances like

plastic explosives(e.g. Heimann or Yxlon International Security GmbH Hamburg, now a Company of General Electric, USA)

■ X-ray Tomography (e.g. GE InVision, USA)

http://news.bbc.co.uk/2/hi/europe/4408455.stm

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Special Technology for checked Luggage only

CTX 5000-Series by InVision Technologies, Newark/Cal. (new name: GE InVision):

■ X-ray computed Tomography + image processing software → automated EDS (explosive detection system) with slicedpictures

■ used in Europe, too

http://www.skyjack.co.il/photogallery.htm

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Special Technology: Backscatter X-ray■ … is a new imaging system, which detects

the radiation which comes back from thetarget.

■ e.g. for detecting weapons or people in containers or trucks

■ e.g. for detecting suspicious objects carriednearby the body but under the clothing(„virtual strip search“)

■ depth of impression is adjustable

■ can be used as far as 50 m away from thetarget

0,1 µSv per Scan is low, but mind the sumand „ALARA“

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Other Technology: Neutron Activation

■ Bombard suspicious luggage with neutrons and read γ-radiation decay signatures to determinethe chemical composition of materials

■ Rather a supplement for other primaryscreening procedures

■ a) γ-radiation emitted andb) infinitesimal hot spots of radioactive atoms

left behind,no data about doses

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Any Radiation Damage to the Luggage?

■ No modification of food orpharmaceuticals

■ No influence on data media or laptops

■ Kodak found out damage to unprocessed films by the CTX-System (fogging). So takethem in your carry-onluggage.

www.kodak.com

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Precautions: 3-„D“-Canon for Radiation Protection

■ 1. DDDDistance

■ 2. DDDDuration of stay

■ 3. DDDDegree of shielding

■ The 4th „D“ for non-ionizing radiationand X-rays: DDDDisconnect

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What are X-ray Hazards due to Screening?

■ No acute health hazard for passengers or staff

■ A small additional dose of ionizing radiation:remember ALARA

■ Particular protection for pregnant womenrecommended

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Laser-Scannersfor Luggage-Identification: Non-Ionizing Radiation

Lasers of category 2 (BGV B2) might injurethe eyes!

There is no sufficient protection by the reflexof the eyelid!

The first protection is prevention of exposure(no possiblity of looking straight into thebeam), instruction of employees and- if necessary - special laser safety goggles

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The future…

Funny Times 2001