Trace particle collection system

1. A handheld portable apparatus for dislodging and collecting target particles from a target surface, the apparatus comprising:

a reservoir of liquefied and pressurized carbon dioxide;

at least one pulsed valve in communication with said reservoir;

at least one expansion chamber in communication with said at least one pulsed valve for forming an aerosol mixture of frozen carbon dioxide particles and carbon dioxide gas;

at least two nozzles in communication with said at least one expansion chamber for directing a spray of said aerosol mixture to substantially overlap at a single focal point downstream of said at least two nozzles;

a particle transport component providing a suction flow into an orifice that entrains particles from said aerosol mixture and target particles dislodged by an impact of said particles from said aerosol mixture;

a collecting medium for accumulating said particles entrained in said suction flow; and

a position-assisting device that assists the operator to position the handheld portable apparatus at an optimal distance from the target surface, wherein the optimal distance is based on the single focal point of the aerosol mixture sprays from the at least two nozzles being located beyond the target surface.

2. The apparatus of claim 1 , wherein said suction flow into an orifice is surrounded circumferentially by a spinning vortex flow.

3. The apparatus of claim 1 , wherein said expansion chamber includes an entrance orifice that has a smaller cross section than the exit orifice.

4. The apparatus of claim 1 , wherein the collecting medium includes at least one of a filter, chemically coated adsorbing surface, metal mesh, three dimensional woven metal, metal wire, metal foil, metal and electrical insulator laminate, or a resistive coating on a substrate.

5. The apparatus of claim 1 , wherein the collecting medium is disposed upstream of said orifice.

6. The apparatus of claim 1 , wherein the collecting medium is disposed within said orifice.

7. The apparatus of claim 1 , wherein said reservoir is a pressurized container of liquefied carbon dioxide gas.

8. The reservoir of claim 1 , wherein said pressurized liquefied carbon dioxide forms an aerosol mixture when it is converted in part to solid particles of frozen carbon dioxide and in part to carbon dioxide gas upon expansion into atmospheric pressure in the expansion chamber.

9. The apparatus of claim 8 , wherein said aerosol mixture is delivered in pulses at predetermined time intervals, and said aerosol particles are delivered in accordance with delivery of said pressurized gas.

10. The apparatus of claim 9 , wherein said valve provides pulses of liquid carbon dioxide greater than 10 milliseconds and less than 1 second in duration.

11. The apparatus of claim 1 , wherein said article transport component includes an impeller of a vortex attractor.

12. The apparatus of claim 1 , further including a second supply of pressurized gas to assist the transport of said aerosol mixture.

13. The apparatus of claim 12 , wherein said second supply of pressurized gas is delivered by at least one of: addition into said expansion chamber, or addition coaxial with and in the direction of the flow from at least one of said at least two nozzles for said aerosol mixture.

14. The apparatus of claim 12 , wherein said second supply of pressurized gas is at least one of: air, nitrogen, argon, carbon dioxide.

15. The apparatus of claim 1 , wherein said position-assisting device is at least one of: an ultrasonic distance measuring device, at least two solid state laser pointers, or an optical reflection sensor.

16. The apparatus of claim 1 , further including a flow-determining device that determines if the flow of carbon dioxide liquid is sufficient for collecting target particles.

17. The apparatus of claim 16 , wherein said flow-determining device is at least one of: temperature sensor mounted on a nozzle, optical reflection sensor viewing the reflectivity of the aerosol mixture, optical transmission sensor viewing the opacity of the aerosol mixture, ultrasonic sensor to sense the density of the carbon dioxide liquid or gas.

18. A method for dislodging and collecting target particles from a target surface, the method comprising:

providing a frozen carbon dioxide aerosol mixture including aerosol particles dispersed in a pressurized gas;

directing said aerosol mixture at said target surface including said target particles, said aerosol particles impacting said target particles causing removal of said target particles from said target surface and causing said target particles to be included in a flow of said pressurized gas with said aerosol particles;

providing a suction flow into which said flow of said target particles, said aerosol particles, and said pressurized gas are directed; and

collecting said particles entrained in said suction flow on a substrate.

19. The method of claim 18 , the method further comprising:

delivering said pressurized gas in timed pulses; and

delivering said aerosol particles in accordance with said timed pulses.

20. The method of claim 18 , further comprising:

combining said pressurized gas with said aerosol particles to form said aerosol mixture.

21. The method of claim 18 , wherein said suction flow is created utilizing a vacuum suction flow into an orifice.

22. The method of claim 21 , wherein said vacuum suction flow into an orifice is bounded circumferentially by a spinning vortex.