Re: Neutron dosimetry using Panasonic UD802

["Sandy Perle" <sandyfl@ix.netcom.com>]

The Panasonic UD802 can be used to measure neutrons, depending on the 
energy that you are concerned with. Calibration is very important, 
and if not done correctly, can result in significant errors to the 
point of no response at all. These are some of the factors you need 
to consider:

1. A single UD802 measures gamma, beta and neutrons. Therefore, the 
algorithm confidence level drops if you want to use a single 
dosimeter to measure all of these fields.

2. Most nuclear power plants in the USA who use the UD802 for 
personnel monitoring generally waer a single UD802 for measuring the 
gamma and beta, and then wear a different UD802 for measuring the 
gamma and neutron. They accomplish this by,

3. Removing the normal whole body badge and use the single neutron 
UD802. The gamma from this badge is added to the cumulative gamma 
from the normal whole body badge for determining the total gamma 
component. 

4. The beta dose is measured only from the normal whole body badge, 
and of course, the neutron component is only measured from the single 
neutron UD802. 

5. A separate caliubration factor MUST be used based on the spectra 
of interest. The factors are significantly different, and testing 
will provide excellent information on the specific correction 
factors.

6. One negative in this process is that any beta exposed to using the 
single neutron UD802 is lost, unless you revert back to trying to 
measure gamma, beta as well as neutron (item 1). This can be 
reconciled with analysis determining the typical beta component in 
the work environment.

The above practice will result in excellent neutron monitoring, as 
well as gamma and beta. The use of a UD809 will provide betteer 
results, but when comparing the benefit versus cost, the UD802 works 
quite well.

Sandy Perle
Technical Director
ICN Dosimetry Division
Office: (800) 548-5100 Ext. 2306 
Fax: (714) 668-3149

E-Mail: sandyfl@ix.netcom.com    

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