British chapter slides in correct 35 mm format

1
RADBALLTM A new departure for 3-D dosimetry
SIMON J DORAN, Steven J Stanley, Paul M
Jenneson Erwan Prott and John Adamovics
2
Summary of talk

• Background
• The RADBALLTM concept
• Simulations
• Early trials and current status of the project

3
Collaboration

• Collaboration with the National Nuclear
  Laboratory
• Spinout company and research arm of British
  Nuclear Fuels Ltd. (BNFL)
• Customers reprocessing plants, reactors, defence
  industry, etc.
• Develops technology for reactor operation and
  decommissioning
• Input into UK nuclear strategy

4
Purpose

• Aim of project
• Develop technique for detecting location of
  radioactive contamination
• Advantages of RADBALLTM
• Deployable device does not require personnel
• Handheld surveys often dangerous/impractical
• Robotic surveys often lack directionality
• Compact
• Robust
• Cheap
• No requirement for power supply

5
Deployment

• Typical areas for deployment
• Contaminated glovebox
• Confined and hard-to-reach spaces
• High radiation areas

6
Competing technology

• Point detectors and film
• Same disadvantages as in radiation therapy!

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Competing technology

• Point detectors and film
• Same disadvantages as in radiation therapy!
• Solid state electronic detectors
• CdZnTe blocks 1.5 1.5 1.0 cm3
• Stack of 11 11 detectors
• 3-D position sensitive detection
• Real-time
• Being developed for homeland security
• Not yet available commercially
• Expensive
• Radiation hard?

8
RADBALLTM concept
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Design criteria and simulations

• Thickness of shell a compromise
• Key function attenuation of unwanted radiation
• Must let through radiation from all angles
  passing through hole

10
Design criteria and simulations

• Thickness of shell a compromise
• Key function attenuation of unwanted radiation
• Must let through radiation from all angles
  passing through hole
• If shell is too thin, there is a loss of contrast.

Radiation sources
Thick shell / high ?
Thin shell / low ?
11
Design criteria and simulations

• Thickness of shell a compromise
• Key function attenuation of unwanted radiation
• Must let through radiation from all angles
  passing through hole
• If shell is too thin, there is a loss of
  contrast.
• If shell is too thick, then rays at oblique
  angles are not seen.

Radiation sources
Thin shell, all holes give signal
Thick shell, some tracks not visualised
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Design criteria and simulations

• Thickness of shell a compromise
• Key function attenuation of unwanted radiation
• Must let through radiation from all angles
  passing through hole
• If shell is too thin, there is a loss of
  contrast.
• If shell is too thick, then rays at oblique
  angles are not seen.
• Compromise is energy-dependent

Anticipated operating region


Almost order of magnitude change in ?
13
Proof of concept irradiation

• First test performed with geometrically simpler
  sample
• Standard cylindrical PRESAGETM sample (6 cm
  diameter)
• Irradiations performed using uncollimated X-ray
  tube to provide point source
• Sample rotated to simulate two point sources in
  different places
• Large dose given to saturate PRESAGETM

Single projection image
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Proof of concept source reconstruction

• Optical CT reconstruction showed clear tracks.

Reconstructed slice
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Proof of concept source reconstruction

• Optical CT reconstruction showed clear tracks.

• Ray tracing performed by hand
• Estimated source distances9.9 and 20.9 cm
• True distances 10 and 20 cm

Reconstructed slice
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Final RADBALLTM product
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Conclusions

• There is a need for a cheap, robust and easily
  deployable imaging detector of radiation.
• We have developed a solution to this problem
  using a combination of
• a specially shaped PRESAGETM sample
• a purpose-designed collimator
• Initial tests have proved encouraging.
• Irradiation is currently ongoing of the next
  sample batch.