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© Copyright 2004 Questions
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CBR Survey and Detection of Radiologicals
A Little History
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Typical of scenes in the 1950s
-----------when the promise of becoming
a millionaire was real. See
Moab History-
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| The cheapest and most prolific detector was the
Geiger Counter. |
A much more sensitive and more expensive detector
was the Scintillation Counter. |
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-Instrumentation-
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Geiger Counters
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Scintillation Counters
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Geiger Muller Tube
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Scintillation Counter Assembly
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| The tube is filled with Argon gas, with ~ 400
Volts applied to the thin wire in the center. When a particle enters the
tube, it pulls an electron from an Argon gas atom. The electron is attracted
to the central wire, and as it rushes towards the wire, the electron will
knock other electrons from Argon atoms, causing an "avalanche". Thus one
single incoming particle will cause a number of electrons to arrive at
the wire, creating a pulse which is amplified and counted. |
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Scintillation Detectors" work by the radiation
striking a suitable material called a Scintillator (such as Sodium Iodide),
and producing a very short flash of light. This is amplified by a "photomultiplier
tube" which results in a burst of electrons large enough to be detected.
Scintillation detectors form the basis of the hand-held instruments used
to monitor contamination in nuclear power stations. They detect Alpha,
Beta, and Gamma radiation. |
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GM Tube
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PM Tube
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GM tube in Alpha Probe
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PM Tube in Alpha Probe
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------------------------ --------My
Prospecting Trip See
my day in Moab- -
Looking for Radiological WMD is like prospecting for Uranium deposits in
the western states.
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That is, a survey in a grid pattern (raster) back and forth logging
sensor data to be analyzed in its entirety looking for subtle trends.
In 1958 I went prospecting for uranium near Moab Utah in the 'Four Corners'
area. I used a Scintillation Counter stuck inside a 75 lb. lead shield
which was mounted under a hole on the passenger side floorboard of my pickup
truck--with its opening facing the ground. |
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Mockup of original outfit
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I used a Scintillation Counter inside a 75 lb. lead shield
which was mounted under a hole on the passenger side floorboard of my pickup
truck--with the opening facing the ground. |
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75 lb. lead shield mounted under passenger side floorboard. |
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| Attached to the
Scintillation counter was a strip recorder of my own design (a rubber bladder
fountain pen, attached to a swing arm that was driven by a modified DC
relay--sans core--as the 'meter movement,' all powered by two KT66 audio
power tubes. Power was supplied by a vibrator powered 12 Volt to 120 VAC
inverter.
The strip chart was 3" adding machine tape. That damn thing actually
worked!
Anyway--again, the idea was to drive in a raster pattern over the terrain
of interest, collecting data, and later analyzing the strips laid out in
rows replicating the survey pattern.
Sadly I didn't find any deposits, but it was quite an adventure for
a 19 year old preparing to go into the service. |
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Four Corners Area
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Typical Terrain
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| NOTES: |
A Little Moab History
In early 1952 an unemployed Texas geologist named Charley Steen
discovered
one of the World's largest concentrations of uranium ore near Moab, Utah.
Steen became an instant millionaire and set off a modern day mining boom.
His Mi Vida Mine is famous for sitting in the largest high-grade pitchblende
(uranium) ore body ever discovered in the United States, last valued at
more than 160 Million (1953 dollars). This discovery unleashed a massive
"uranium boom" on the Colorado Plateau, and turned tiny Moab, UT into "the
uranium capital of the world." The mine closed in the 1980s.
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My day in Moab
On my prospecting trip in 1958 I was in Moab and saw the "Steen Estate."
It was a Butte rising nearly straight up with a carved out driveway that
lead from the highway circuitously to the top. There were cyclone fencing
completely surrounding the base of the butte, as was the driveway on both
sides, with gates at intervals. At the time I was there, there were at
least three core drilling machines spaced out on the driveway, looking--I
suppose--for more uranium.
Finally, at the top of the butte, the house, grounds and pool was surrounded
by a high wood privacy fence. It was all too surreal.
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| Another prospector of note was Vernon Pick,
a middle-aged electrician from Minnesota, who discovered the Delta Mine
(Hidden Splendor) northwest of Hanksville in 1952.
Pick extracted a million dollars worth of ore before selling the mine
to international financier Floyd Odlum's Atlas Corporation for $9 million
and a custom-converted PBY airplane.
Odlum was certain the mine was a rich find and his geologists estimated
the mine held 540,000 tons of uranium ore with an in-place value of forty
dollars per ton. This would have made the mine worth nearly 22 million
dollars. However, the Atlas Corporation only extracted 90,000 tons
of ore from the mine before abandoning it in 1957. Local wags then dubbed
the mine "Odlum's Hidden Blunder". After Atlas Corporation left several
others tried unsuccessfully to extract ore. The Uranus Corporation took
over the mine for a short time in cooperation with Central Oil. The Hidden
Splendor Mine closed in 1957 and was eventually sold for taxes.
In November 1, 1954 Life Magazine (Color cover - Dorothy Dandrige) published
an 11-page article titled "Vernon Pick's $10 million Ordeal" that detailed
the discovery of the Delta Mine. Publicity from this article greatly increased
prospecting in the San Rafael Swell and surrounding Colorado Plateau and
made the Delta Mine famous. |
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© Copyright 2004 Questions
or Comments:
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