Radiation Detection Techniques for Public Health Emergencies

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Radiation Detection Techniquesfor Public Health
Emergencies

• Presented by the Bureau of Environmental
  Radiation Protection's Radiological Emergency
  Response Section
• Cynthia Costello, Chief
• Mark Virgil, Associate Radiological Health
  Specialist
• Michael Harmon, Associate Radiological Health
  Specialist
• Michael Soucie, Research Scientist II

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Measurement Equipment
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GM probe survey meter (Ludlum 44-9 pancake
probe and Model 14 C)

• Used for beta gamma detection and measurement
• Ratemetercpm or exposure rate in Roentgen/hr
  (R/hr) or milliR/hr (mR/hr)
• Non-linear energy response / nuclide-specific
  calibration with Cs-137 (also energy compensated
  instrument is available)
• Efficiency factors for beta vs. gamma
• (Typically 5-C-14 22-Sr-90/Y-90
• 19-Tc-99 32-P-32 15-Pu-239)
• Measures surfaces, wipes, air samples
  (particulates iodine cartridges)
• Connect probe to a scaler or SCA to obtain
  concentrationsG?/G?
• Need fixed geometry sample holder for wipes air
  filters
• Need beta gamma disc sources for probe
  efficiency

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GM ENERGY RESPONSE CURVE
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NaI probe survey meter (Ludlum 44-10 probe and
Model 14C)

• Specific for gamma detection measurement
• Ratemeter (more sensitive than GM probe)- cpm or
  if calibrated, exposure rate in Roentgen/hr
  (R/hr) or milliR/hr (mR/hr)
• Non-linear energy response / nuclide-specific
  calibration with Cs-137
• Measures surfaces, wipes, air samples
  (particulates iodine cartridges)
• Connect probe to a scaler or SCA to obtain
  concentrationsGross Gamma
• Need fixed geometry sample holder for wipes air
  filters
• Need gamma disc sources for probe efficiency

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NaI ENERGY RESPONSE CURVE
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MicroR meter (Ludlum Model 19)

• Compact design-internal 1x 1 NaI detector for ?
  detection/measurement
• Very sensitive/low range only measures up to
  5000 microR/hr
• Non-linear energy response / nuclide-specific
  calibration with Cs-137

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Pressurized Ion Chamber or PIC (Inovision Model
451P)

• Measures exposure rate and dose rate
  simultaneously for gamma only
• Provides integrated dose
• Almost linear energy response from 70 keV to
  2000keV
• Within /- 20 of true value
• Good sensitivity
• Range 0 to 5 R/hr (autoscales from ?R to mR to R)
• 125psi (8 atm)
• Requires 2-minute warm-up

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Gas-filled Proportional Detector Meter
(Thermoelectron ESM FHT 752SH ESM FH40G-L)

• Helium-3 neutron probe
• Detecting/locating neutron sources
• Neutron exposure rate
• Internal ? detector for ? exposure and dose rate
• Light weight
• Accelerator surveys

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Solid scintillator probe meter(Ludlum Model
43-89 Model 2224)

• Simultaneous alpha-beta detection measurement
• Read alpha only, beta only or alpha/beta in
  counts per minute
• 100 cm2 probe
• Scintillator is ZnS
• Mylar window is somewhat fragile-if damaged,
  light leaks will result

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Radioisotope Identifier (RII) Exploranium
(Model GR-135M)

• Energy compensated GM NaI detector with
  multichannel analyzer
• Ratemeter (gamma only) - cpm or exposure rate in
  Roentgen/hr (R/hr) or milliR/hr
• Nuclide identification for gamma-emitters
• Supplements GM/NaI/PIC exposure rate
  measurements for ? emitters
• With add-ons, may be used to determine
  concentrations
• Need fixed geometry sample holder for wipes, air
  filters, etc.
• Need gamma disc solid matrix sources for system
  efficiency

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Intrinsic Ge gamma spectroscopy system (portable)

• Superior nuclide identification
• (gamma emitters only)
• Requires lap top PC with software loaded
• With add-ons, may be used to determine
  concentrations
• Need fixed geometry sample holder for wipes, air
  filters, etc.
• Need gamma disc solid matrix sources for system
  efficiency
• Significant preparation time
• Requires 30 liters LN 8 hrs. pressurization of
  30-L storage dewar
• 20 30 minutes fill time from storage dewar into
  5-L MAC dewar
• Need 4 hours to chill detector to operating
  temperature

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Personal Dosimeters

• Designed to measure the radiation dose a person
  receives
• Electronic (pager) dosimeters often used by law
  enforcement and other emergency responders as
  radiation detectors.

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Sample Typesand Collection Procedures
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Surfaces

• _at_ contact ( 1 cm) surface contamination,
  detection of ?, ?, ?, and measurement of exposure
  rate
• _at_ 3 feet ambient/area exposure rate for ?
  emitters

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Wipe Samples

• 2-inch or 47mm diameter filter paper
• 100 cm2
• 10 cm x 10 cm (4 x 4) or
• 2 cm x 50 cm (3/4 x 20)
• Wet or dry

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Air Particulate Samples

• RADECO Model H-809C portable air sampler
• 2-inch diameter glass fiber filter
• 50 cubic feet _at_ 2 cfm
• Auto battery or 12-volt DC power supply required

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Gaseous Iodine and Some Organic Iodine Compounds
in Air Samples

• RADECO Model H-809C portable air sampler
• 2-inch diameter charcoal cartridge
• 50 cubic feet _at_ 2 cfm
• Auto battery or 12-volt DC power supply required

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Water Samples

• Grab sample - surface water
• Preferred volume is 2 liters, minimum volume is
  250 ml

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Soil Samples for Surface Contamination

• Preferred quantity 10 cm x 10 cm x 2 cm (4 x
  4 x ¾)
• DOE/FRMAC soil sampling tool or 4 putty knife
  and trowel or scoop
• Meter reading vs. soil concentration

Other Sample Types

• Vegetation
• Milk
• Produce and other foods

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Laboratory Analysis

• Wadsworth Center
• Laboratory of Inorganic and Nuclear Chemistry

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QUESTIONS?
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THANK YOU !!!