Proton Recoil and Other Spectrometers

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

Figure 6.5.

Neutron Energy Spectra as Measured by the Multisphere Spectrometer at 50 cm

from Plutonium Metal, PuO2, and PuF4 Sources

The liquid scintillator spectrometer has the advantage that it is very sensitive

and can operate at low dose rates. It is useful over an energy range extending

from about 1 MeV to 20 MeV. Neutron dose equivalent can be calculated from

the measured spectra using the conversion factors given in the Implementation

Guide. External Dosimetry Program (DOE, 1999e). The dose equivalents

calculated from liquid scintillator measurements are reasonably accurate (10%

to 20%) for lightly moderated plutonium spectra. Because of the lower energy

cut-off of liquid scintillator spectrometers, they may not provide accurate dose

equivalent values outside heavily shielded facilities, such as plutonium storage

vaults with thick concrete walls.

6.3.6.4 Proton Recoil and Other Spectrometers

There are a number of other spectrometer systems that are available that have

been used successfully for neutron spectral measurements in the field. Of

particular interest is a spectrometer employing five different proton recoil

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