Potential Doses to Individuals Screened with Whole-Body Security Screening

Systems: OSL Dosimeter Measurements

Craig R. Jones, CHPFran Szrom, CHP

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June 2011

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Disclaimer

The appearance of a manufacturer’s equipment does not imply endorsement of the equipment by the Army, DOD, or the

Federal Government.

• Individual Screened– General-Use: 0.25 μSv (25

μrem) per screening

– Limited-Use: 0.01 mSv (1 mrem) per screening

– 0.25 mSv (25 mrem) per year

• Operator’s/Bystanders Annual Limit

– 1 mSv (100 mrem) per year

• Inspection zone – operators and bystanders outside inspection zone during screening

Introduction to Personnel Security Screening Systems

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• Purpose: Evaluate potential dose to the individual being screened

• Field measurements

– ANSI N43.17-2009 methodology (Reference Effective Dose)

• Energy correction, Dose conversion factors

– No estimate of eye or skin doses with survey instruments

• Dosimeter study requires

– Very large number of screenings

– Automated method for initiating screenings

– Using DDE as a surrogate for Reference Effective Dose

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Background

Test Setup – Repetitive Screening

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• System 1:– Robotic solution

– 93,105 screenings

– ~ 2 weeks

• System 2:– Software solution

– 8,627 screenings

– < 1 week

Test Setup - Phantoms

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• Maximum DDE per screening:

– 4,200 μSv/93,105 screenings = 0.045 μSv (4.5 μrem)

• Average DDE per screening:

– 3,559 μSv/93,105 screenings = 0.038 μSv (3.8 μrem)

• Minimum DDE per screening:

– 2,560 μSv/93,105 screenings = 0.027 μSv (2.7 μrem)

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System 1: Deep Dose Equivalent

Screenings to Reach 0.25 mSv (25 mrem)Annual Weekly Daily

Max DDE 5,542 107 15

Avg DDE 6,540 126 18

Min DDE 9,092 175 25

• Maximum LDE per screening:

– 8,450 μSv/93,105 screenings = 0.091 μSv (9.1 μrem)

• Average LDE per screening:

– 6,226 μSv/93,105 screenings = 0.067 μSv (6.7 μrem)

• Minimum LDE per screening:

– 4,710 μSv/93,105 screenings = 0.051 μSv (5.1 μrem)

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System 1: Lens Dose Equivalent

Screenings to Reach 15 mSv (1500 mrem)Annual Weekly Daily

Max LDE 165,275 3,178 454

Avg LDE 224,329 4,314 616

Min LDE 296,513 5,702 815

• Maximum SDE per screening:

– 15,050 μSv/93,105 screenings = 0.162 μSv (16.2 μrem)

• Average SDE per screening:

– 10,552 μSv/93,105 screenings = 0.113 μSv (11.3 μrem)

• Minimum SDE per screening:

– 7,420 μSv/93,105 screenings = 0.080 μSv (8.0 μrem)

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System 1: Shallow Dose Equivalent

Screenings to Reach 50 mSv (5 rem)Annual Weekly Daily

Max SDE 309,319 5,948 850

Avg SDE 441,163 8,484 1,212

Min SDE 627,392 12,065 1,724

System 2

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• Maximum DDE per screening:

– 540 μSv/8,627 screenings = 0.063 μSv (6.3 μrem)

• Average DDE per screening:

– 416 μSv/8,627 screenings = 0.048 μSv (4.8 μrem)

• Minimum DDE per screening:

– 250 μSv/8,627 screenings = 0.029 μSv (2.9 μrem)

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System 2: Deep Dose Equivalent

Screenings to Reach 0.25 mSv (25 mrem)Annual Weekly Daily

Max DDE 3,994 77 11

Avg DDE 5,184 100 14

Min DDE 8,627 166 24

• Maximum LDE per screening:

– 650 μSv/8,627 screenings = 0.075 μSv (7.5 μrem)

• Average LDE per screening:

– 516 μSv/8,627 screenings = 0.060 μSv (6.0 μrem)

• Minimum LDE per screening:

– 280 μSv/8,627 screenings = 0.033 μSv (3.3 μrem)

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System 2: Lens Dose Equivalent

Screenings to Reach 15 mSv (1500 mrem)Annual Weekly Daily

Max LDE 199,085 3,829 547

Avg LDE 250,785 4,823 689

Min LDE 462,161 8,888 1,270

• Maximum SDE per screening:

– 780 μSv/8,627 screenings = 0.090 μSv (9.0 μrem)

• Average SDE per screening:

– 577 μSv/8,627 screenings = 0.067 μSv (6.7 μrem)

• Minimum SDE per screening:

– 280 μSv/8,627 screenings = 0.033 μSv (3.3 μrem)

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System 2: Shallow Dose Equivalent

Screenings to Reach 50 mSv (5 rem)Annual Weekly Daily

Max SDE 553,013 10,635 1,519

Avg SDE 747,574 14,376 2,054

Min SDE 1,540,536 29,626 4,232

• Both systems evaluated comply with the ANSI/HPS N43.17-2009

dose per screening limit for general-use

• DDE is comparable to the Reference Effective Dose (ANSI/HPS

N43.17-2009)

• The annual number of screenings per individual is limited by the

DDE/Reference Effective Dose, not LDE or SDE.

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Summary

Dose per Screening (μSv (μrem))

  Avg DDE Ref Eff Dose

System 1 0.038 (3.8) 0.033 (3.3)

System 2 0.048 (4.8) 0.046 (4.6)