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Survey and Detection of Clandestine WMD
Mobile Detection Systems hitchhiking a ride on Vehicles

CBR Survey-----Preparedness-----Links:-----
Abstract
This Web Page will describe a novel approach to "WMD Hunting," using techniques similar to Uranium Prospecting. We will introduce the novelty of hitching a ride on taxicabs and/or similar fleet vehicles. Although this approach is applicable to Chemical and Biological WMD detection, this page will mainly cover Radiological weapons.

Review of the fundamentals of radiological survey (prospecting) and the obstacles to be overcome. Existing detection technology as well as emerging technology. Also a typical survey instrumentation platform, including detectors, data gathering, storage and transmission, as well as centralized analysis for "connecting the dots."

Finally,  refreshers on some of the pertinent technology with historical perspectives on uranium prospecting techniques.

Overview:
One of America's first lines of defense against nuclear terrorism is the Nuclear Emergency Search Team (NEST). NEST consist of a force of 1,000 civilians, most of whom come from the nuclear-weapons industry. Aware of what such weapons can do, they have been selected to find and deactivate nuclear bombs and materials in the hands of terrorists.

These weapons could be anywhere; from a shipping container to someone's basement.

Proposed:
A method for discovering Clandestine Weapons of Mass Destruction (CWMD) by hitchhiking sensors on existing Fleet Vehicles.

This system would utilize fleet vehicles such as commercial taxicabs, police cars, mail trucks, and other similar ubiquitous, high mileage, fleet vehicles.

Such vehicles would be equipped with an array of sensors for the detection of chemical, biological, and radiological weapons or materials. 

Information gathered, along with GPS location data, is transmitted in real, or near real-time, via cellular radio or satellite, to a central authority for rapid analysis.

The unique feature of such a system is the random nature of its coverage and the high mileage covered in a relativity short time, as well as the diversity of sensing vehicles; all for "free." 

Statistically, there are two components of this type of random search: temporal and spatial sampling. In the case of taxis and police cars, both dimensions are at play; where as, mail trucks would be only temporal--same routes, at regularly scheduled sampling times.
 

Factors influencing Detection of Nuclear Radiation
Detecting clandestine nuclear materials is not unlike prospecting for Uranium deposits in the western desert. In both cases there are several factors which influence detection:

1)_ Intensity of the radioactive source.

2)_ Attenuation of radiation due to Shielding. The amount and type of shielding material, e.g., to attenuate the radiation by half requires: Lead = 0.49", Steel = 0.87", Concrete = 5.0".

3)_ Detector types, and their dimensions.

4)_ Background radiation (background count). 
Background (natural radiation) radiation is caused by cosmic rays, naturally occurring radiation from soil, plants, nuclear fallout, etc. It is a matter of Signal to Noise (SNR).

5)_ The Distance between the source and detector reduces radiation intensity--in air--according to the Inverse Square Law function, i.e., the amount of radiation at a  given distance from the source is inversely proportional to the square of that distance, e.g., if the exposure rate at 1 meter equals 100 mR/hr then the exposure rate at 2 meters will be 25 mR/hr.     see fig
 


Some typical vehicles used by system; note GPS antennas---more
..
-Uranium Prospecting-

Using Geiger Counter

Using Scintillation Counters
Vehicular survey covers more area---more
Arial survey covers much more area
Basic Survey Instruments

Geiger Counter with Probe

Scintillation Counter

Geiger Muller Tube

Scintillation Counter Front End
The Geiger Muller tube is filled with Argon gas, with ~ 900 Volts D.C. 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.  Scintillation Detectors work by the radiation striking a suitable material called the Scintilator (such as Sodium Iodide), produces a very short flash of light. This light falls on the end of a very sensitive "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, Gamma, X-ray, and Nutron radiation.
   In the case of a nuclear bomb, radiation detectors will be chiefly looking  for Neutrons and Gamma Rays; both of which, Uranium U235 and Plutonium Pu235 emit.

However, so called "Dirty Bombs" may use other  radioactive isotopes such as depleted Uranium, depleted Plutonium, medical isotopes, etc.

There may be a requirement to to detect Alpha and Beta particles using 'sniffer' technology similar to Chemical and Biological sensors. [1]
[1] Alpha and Beta particles are difficult to detect, e.g., Alpha particles can be blocked by a sheet of paper.

..
 

-Riding piggyback in the trunk: sensing, collection, and communication units -
..
 

System block diagram-
..
 
Detection Sensitivity is a function of Inverse Square Law:-
The radiation field decreases with distance from the source as a function of the Inverse Square Law, which states that the amount of radiation at a given distance from a source is inversely proportional to the square of that distance.
more info
 
..
 
Residential neighborhood overlayed with tracking and sensor data (3 vehicles).
Note the green circle is the approximate geometrical center of interest--"hot spot."
 
..
 
Detector Shadowing

The red line indicates the "shadowing" boundry,
notice the vehicle sensor package is at a severe 
disadvantage, especially if the package is located 
in the trunk.
Car Top Sensor Package
A possible location for Sensor Package
Vehicle mounted GPS and Cellular modem Antennas; 
Satellite data links can be used in place of Cellular modem.
....
CBR Survey----Preparedness-----Links:-----
Various Terror Scenarios
One chilling aspect of the danger al Qaeda poses is the possibility of their having suitcase Nukes!

A few of those strategically placed and all going off at the same instant could bring down this country so easily; and think of all our enemies "piling on" is that event; we would all have to take up speaking Russian, French, German, Arabic, Farsi and pig latin ...

Anyway, I was thinking about how to detect clandestine nukes, something NEST is charged with doing.
 

It occurred to me that because detecting that kind of target is like prospecting
for Uranium deposits in the western states.
Survey Vehicle

Prospecting for surface deposits of Uranium 
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.

When I went prospecting for uranium in the 'Four Corners" area back in 1958; I
used a Scintillation Counter stuck inside a 75 lb lead shield which was mounted
in a hole on the passenger side of my pickup truck--with an opening facing the
ground.

-----Field Portable Gieger Counter
Attached to the Scintillation counter was a strip recorder of my own design (a
rubber bladdered 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. All of this powered by a vibrator 12 Volt to 120 VAC
inverter).

-----Field Portable Scintillation Counter
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.

..
 
  LINKS:
----Glossary
----Isotopes
----Depleted Plutonium and depleted Uranium
----Nuclear Materials Management & Safeguards System (NMMSS)
----Nuclear Primer
----GammaCamTM Radiation Imaging System
----Technical Aspects of Nuclear Proliferation  .pdf  ~2MB
----Weapons Primer
----
----"Suitcase Nukes:" Permanently Lost Luggage    2/13/2004
--------"Suitcase Nukes": A Reassessment   9/23/2002
----Chemical & Biological Weapons Resource Page
----Pattern Recognition and Intelligent Sensor Machines Laboratory
----
----Preparedness for CBR Attack
----Chemical/Biological/Radiological Incident Handbook
----http://www.radrisk.com/detectors.htm#survey
----Cardinal Surveys Company
 --------
  Terms:
----CBR    Chemical, Biological, Radiological
----NBC    Nuclear, Biological, Chemical
----WMD    Weapons of Mass Distruction
----W
----W
----W
----W
 
..
  Appendix
  Detection Distances
Inverse Square Law:

Inverse Square Law: The radiation field decreases with distance from the source. When considering a point source in  air, the decrease will follow the inverse square law, which states
that the amount of radiation at a  given distance from a source is inversely proportional to the square of the distance.
I/i = d2/D2
or
I x D2 = i x d2

(Where I = intensity at a distance (D) from a point source, and i = intensity at a distance (d) from the same source).
Example: If the exposure rate at 1 meter equals 100 mR/hr then the exposure rate at 2 meters equals 25 mR/hr.
 

Exposure Rates VS. Distance - 100 mci Sources
Radioactive Isotope mR/hr @ 3' mR/hr @ 6' mR/hr @ 9'
192Ir 61 15.25 6.8
131I 25 6.25 2.8
see fig
Half-value Layer:
The half-value layer is the thickness of a substance which reduces the intensity of a beam of radiation to one-half of its initial value. The half-value layer is a function of the energy of the gamma and the composition of the shield or absorber. Examples:
Half-Value Layers
Radioactive Material -Half-Life --Lead-- --Steel-- Concrete
Radionuclide 60Co 5.27 years 0.49" 0.87" 5.0"
Radionuclide 137Cs 30.07 y 0.25" 0.68" 2.1"
192Ir 73.831 d 0.19" 0.50" 1.9"
Radioiodine 131I 8 days 0.14" 0.37" 1.4"

60Co Cobalt  radionuclide  halflife 5.27 years.
137Cs  Cesium  radionuclide
192Ir Iridium 
131I Iodine  Radioiodine 131I has a half life of 8 days 

Activity [Curie]:
The activity of a radioactive substance is often designated by the Curie [Ci]. The Curie is not a measure of dose; it merely states the amount of a radioactive disintegrations per unit time. The Curie is a unit of measurement defined as the activity of a radioactive substance disintegrating 
at a rate of: 3.7 x 1010 disintegrations per second.
Activity Units
Name Definition Abreviation
Millicurie 1/1,000 Ci [mCi]
Microcurie 1/1,000,000 Ci [uCi]
Nanocurie 1/1,000,000,000 Ci [nCi]
Picocurie 1/1,000,000,000,000 Ci [pCi]
Curie: 
Units of measurement. One curie is that quantity of a radioactive nuclide disintegrating at the rate of 3.700 x 1010 atoms per second.
Units Of Activity
Units Disintegrations / Second
microcurie 3.7 x 104
millicurie 3.7 x 107
picocurie 3.7 x 10-2
Energies in Electron Volts

Room temperature thermal energy of a molecule..................................0.04 eV

Visible light photons....................................................................................1.5-3.5 eV

Energy for the dissociation of an NaCl molecule into Na+ and Cl- ions:.............................................................................................4.2 eV

Ionization energy of atomic hydrogen ........................................................13.6 eV

Approximate energy of an electron striking a color television screen...................................................................................20,000 eV

High energy diagnostic medical x-ray photons...............................200,000 eV (=0.2 MeV)

Typical energies from nuclear decay:
(1) gamma..................................................................................................0-3 MeV
(2) beta.......................................................................................................0-3 MeV
(3) alpha....................................................................................................2-10 MeV

Cosmic ray energies ........................................................................1 MeV - 1000 TeV


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