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RE: FIDLERS
Last week someone expressed some questions concerning the history of the
FIDLER.
The following is a response from Los Alamos National Laboratory. Hope
this helps
Jim Straka
DOE/AL
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Jim:
The FIDLER (Field Instrument for the Detection of Low Energy Radiation)
is actually a detector that can be used with many different instruments
or electronics packages. It was developed in the late 1960's at
Lawrence Radiation Laboratory (now Lawrence Livermore National
Laboratory). In 1966 there was an accident in Palomares, Spain that
released significant quantities of weapons grade plutonium over a large
area. It became immediately clear that direct alpha survey instruments
were ineffective in characterizing large area ground contamination, so
the FIDLER was consequently developed. It was first used extensively in
Thule, Greenland in 1968, the site of another accident similar to the
one in Palomares.
The detector utilizes a 5" photomultipliar tube and a 5" diameter X
.063" thick NaI(Tl) scintillation crystal with a .010" beryllium
entrance window. It is well suited for detecting low energy gammas and
x-rays up to about 100 keV. One of the first commercial manufactures
was Harshaw, but it has since been made by others such as Alpha Spectra
and Bicron.
Originally the detector was coupled to a single channel analyzer such as
the PRM-5-3. In this configuration, there was a window set up on either
the 60 keV gammas from Am-241, or on the 17 keV (ave) x-rays from both
Am-241 and several Pu isotopes. It is now used very effectively with a
multi-channel analyzer.
If more information is needed, please feel free to contact me.
Darrin Stafford
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OO
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Darrin P. Stafford
RCT/Hazmat Specialist
Hazardous Materials Response, ESH-10
Los Alamos National Laboratory
Ph. (505)665-5065
Fax (505)665-4477
Pager (505)996-3243
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