Method and system for imaging a radiation source

1. A method for imaging and/or locating a radiation source,

said method comprising the steps of

recognizing an interaction between a radiation emission and a sensor;

converting a parameter of said radiation emission into digital form;

calculating a Compton cone from a parameter of said radiation emission;

tracing at least one individual Compton cone on to a unit sphere having preselected characteristics by plotting a plurality of points on the sphere, each point evaluated by the equation

{ c·s ≦cos θ cos δ+sin θ sin δ OR cos θ≧cos δ} AND { c·s ≧cos θ cos δ−sin θ sin δ OR cos θ≦−cos δ}

wherein c is the Compton cone axis direction vector, s is the vector from the center of the sphere to said point on the sphere, θis the Compton scatter angle, and δis the estimated angular uncertainty;

computing a result indicative of a preselected characteristic of said radiation source; and

outputting said result.

2. The method of claim 1 wherein θfalls within the range between 0 and π, inclusive, and δ falls within the range between 0 and π/2, inclusive.

3. The method of claim 2 wherein δ is a constant,

4. The method of claim 1 further comprising the step of constructing a direction histogram from the points on the sphere,

5. The method of claim 4 further comprising the step of reducing the direction histogram in at least one dimension so as to estimate the direction to a source.

6. A method for imaging and/or locating a radiation source comprising the steps of:

recognizing an interaction between a radiation emission and a sensor;

converting a parameter of said radiation emission into digital form;

calculating a first Compton cone from a parameter of a first radiation emission;

calculating a second Compton cone from a parameter of a second radiation emission; and

intersecting said first and second Compton cones with an image surface to obtain at least one intersection point;

iterating said east one intersection point over a preselected number of prior first second Compton cones; computing a result indicative of a preselected characteristic of said radiation source; and

outputting said result.

7. The method of claim 6 where the image surface is a sphere.

8. The method of claim 6 further comprising the step of preselecting cones based upon energies observed.

9. The method of claim 6 further comprising the step of preselecting cones based upon energies from a list of radioisotopes.

10. The method of claim 6 further comprising the step of constructing a direction histogram from the intersection points.

11. A device comprising a field programmable gate array arrangement that performs Compton cone imaging by tracing at least one individual Compton cone on to a unit sphere having preselected characteristics by plotting a plurality of points on the sphere, each point evaluated by the equation

{ c·s ≦cos θ cos δ+sin θ sin δ OR cos θ≧cos δ} AND { c·s ≧cos θ cos δ−sin θ sin δ OR cos θ≦−cos δ}

wherein c is the Compton cone axis direction vector, s is the vector from the center of the sphere to said point on the sphere, θ is the Compton scatter angle, and δ is the estimated angular uncertainty.

12. A device comprising a computer readable medium that performs Compton cone imaging by

calculating a first Compton cone from a first parameter of a first occurrence,

calculating a second Compton cone from a second parameter of a second occurrence;

intersecting said first and second Compton cones with an image surface to obtain at least one intersection point; and

constructing a direction histogram from the intersection points.