2. For neutron dose equivalent rate monitoring?

Consider:

• An absorbed dose delivered by neutrons has a much higher radiobiological effectiveness than the same absorbed dose delivered by X or γ radiation.
• Monitoring neutron dose equivalent rate is made difficult by the extremely wide energy range that is routinely encountered (0.025 eV to 10 MeV or higher around high energy accelerators) and the fact that instruments do not have the correct dose equivalent response over this energy range.
• If the neutron spectrum is well characterised, it may be possible to select an instrument with a good response in the region where the majority of the dose equivalent occurs. Alternatively, field specific correction factors based on the spectrum can be derived. 

All common units are based on detecting low energy (thermal) neutrons.  A large mass of moderating material, normally polyethylene, surrounds the detector and is used to slow down the neutrons by collision. This, in combination with a thermal neutron absorbing layer, produces a tolerable energy response, but makes the instruments very heavy, typically 6  to 9 kg.

Detector characteristics (112 KB)

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• Practical radiation monitoring
  
• Practical radiation monitoring units
• Radiation monitoring strategy
• Choice of radiation instrument 
• Radiation monitoring techniques  
• Estimating surface radioactivity
• Radiation instrument calibration
• Uncertainties in radiation measurement 
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