Quantcast Neutron-Measuring Component of Dosimeter - doe-std-1128-98_ch10207

 

Click here to make tpub.com your Home Page

Page Title: Neutron-Measuring Component of Dosimeter
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Back
Fixed and Personnel Nuclear Accident Dosimeters - doe-std-1128-98_ch10206
Up
DOE Standard Guide of Good Practices for Occupational Radiological Protection In Plutonium Facilities
Next
Responsibilities of Health Physics Staff - doe-std-1128-98_ch10208


DOE-STD-1128-98
Neutron-Measuring Component of Dosimeter. Criticality accidents
create a wide range of neutron energies. Since the neutron dose per unit
fluence is strongly dependent on neutron energy, knowledge of the neutron
energy spectrum is important in accident dosimetry. In criticality accidents,
neutrons with energies greater than about 100 keV contribute most of the
dose; therefore, measurement of the fast neutron dose is of most
importance. See Delafield (1988) for a review of the different types of
neutron dosimeters available for accidents.
Gamma-Measuring Component of Dosimeter. Delafield (1988) noted
that the ratio of the gamma rays to neutron dose will vary according to the
type of critical assembly and whether or not additional shielding is present.
For unshielded assemblies, the gamma-to-neutron ratio can range from 0.1
for a small heavy metal system up to about 3 for a small hydrogen-
moderated solution system. A concrete or hydrogenous shielding material
will increase the gamma-to-neutron ratio. Gamma dose can be determined
by TLD, film, or radiophotoluminescent glass.
Dosimeter Comparison Studies. Sims and Dickson (1979) and Sims
(1989) present a summary of nuclear accident dosimetry intercomparison
studies performed at the Oak Ridge National Laboratory Health Physics
Research Reactor. The most recent summary (Sims, 1989) showed that of
the 22 studies conducted over 21 years, 68% of the neutron dosimeter
results were within the 25% accuracy standard and 52% of the gamma
dosimeter results were within the 20% accuracy standard. Most
measurements that failed to meet the accuracy standards overestimated the
actual dose. Some of their other findings include the following:
-- Doses from hard neutron energy spectra are more accurately measured
than those from soft energy spectra
-- The threshold detector unit (TDU) is the most accurate type of nuclear
Accident neutron dosimeter; however, its use is declining due to
increasingly strict control of small quantities of fissionable materials
-- Activation foils (ACT) are the most popular nuclear accident neutron
dosimeter
-- For gamma dosimeters, TLDs are the most popular and the least
accurate, and film is the least popular and the most accurate.
7-15


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc.