Pressure Activated Sampling System

1 . A system for screening an item for prohibited material, the system comprising:

a pressure chamber adapted to contain at least one item to be screened for prohibited material and being adapted to contain at least one filler object;

a pressurized gas source connected to provide pressurized gas to the pressure chamber;

a valve for venting the pressure chamber to an ambient atmosphere;

a controller operable to control a pressurization of the pressure chamber by the pressurized gas source and to control the valve to initiate a rapid decompression of the pressure chamber; and

a sample collector positioned to collect samples of substances removed from the at least one item by the rapid decompression.

2 . The system of claim 1 wherein the at least one filler object comprises at least one substantially incompressible filler object.

3 . The system of claim 1 wherein the at least one filler object comprises at least one polyurethane foam object.

4 . The system of claim 1 wherein the at least one filler object comprises at least one formed metal object.

5 . The system of claim 1 wherein the pressure chamber includes at least one door for loading the at least one item into and out of the pressure chamber, at least one of the at least one filler object is connected to the at least one door.

6 . The system of claim 1 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially beneath the at least one item to be screened for prohibited material.

7 . The system of claim 1 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially above the at least one item to be screened for prohibited material.

8 . The system of claim 1 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially adjacent to the at least one item to be screened for prohibited material.

9 . A method for screening an item for prohibited materials, the method comprising:

placing an item in a pressure chamber, the pressure chamber including at least one filler object;

pressurizing the pressure chamber up to a predetermined pressure level;

decompressing the pressure chamber at a rapid rate relative to a rate of pressurization; and

collecting samples of substances removed from the item by the rapid decompression.

10 . The method of claim 9 wherein the at least one filler object comprises at least one substantially incompressible filler object.

11 . The method of claim 9 wherein the at least one filler object comprises at least one polyurethane foam object.

12 . The method of claim 9 wherein the at least one filler object comprises at least one formed metal object.

13 . The method of claim 9 wherein the pressure chamber includes at least one door for loading the at least one item into and out of the pressure chamber, at least one of the at least one filler object is connected to the at least one door.

14 . The method of claim 9 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially beneath the at least one item to be screened for prohibited material.

15 . The method of claim 9 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially above the at least one item to be screened for prohibited material.

16 . The method of claim 9 wherein the pressure chamber is adapted to contain at least one of the at least one filler object located at least partially adjacent to the at least one item to be screened for prohibited material.

17 . The method of claim 9 wherein the rapid rate is at least about ten times the rate of compression.

18 . The method of claim 9 further comprising generating pressure pulses after the pressure chamber reaches the predetermined pressure level and before the rapid decompression of the pressure chamber.

19 . The method of claim 9 wherein venting the pressure chamber to the ambient atmosphere allows air to escape the pressure chamber at a high velocity.

20 . The method of claim 9 wherein the high velocity comprises a velocity sufficient to effectively strip particles adhering to a surface of the item.

21 . A system for screening an item for prohibited material, the system comprising:

a pressure chamber adapted to contain at least one item to be screened for prohibited material;

a pressurized gas source connected to provide pressurized gas through multiple nozzles to the pressure chamber;

multiple valves for venting the pressure chamber to an ambient atmosphere;

a controller operable to control multiple pressurization of the pressure chamber by the pressurized gas source and to control the valves to initiate rapid decompressions of the pressure chamber opening some but not all valves to vent the pressure chamber and initiate a purge of the pressure chamber after the rapid decompression by opening additional valves to vent the pressure chamber than used in the rapid decompression of the pressure chamber and using the multiple nozzles to provide gas to the pressure chamber; and

a sample collector positioned to collect samples of substances removed from the at least one item by the rapid decompression.

22 . The system of claim 21 wherein the purge is initiated once the pressure in the pressure chamber falls to a preset pressure level.

23 . A method for screening an item for prohibited materials, the method comprising:

placing an item in a pressure chamber;

pressurizing the pressure chamber a first time up to a first predetermined pressure level;

after pressurizing the pressure chamber the first time, decompressing the pressure chamber a first time at a first predetermined rapid depressurization rate;

after decompressing the pressure chamber the first time, pressurizing the pressure chamber a second time up to a second predetermined pressure level;

after pressurizing the pressure chamber the second time, decompressing the pressure chamber a second time at a second predetermined rapid depressurization rate; and

collecting, from the sample collector, samples of substances removed from the item by the rapid decompressions.

24 . The method of claim 23 wherein the first predetermined pressure level is substantially the same as the second predetermined pressure level.

25 . The method of claim 23 wherein the second predetermined pressure level is higher than the second predetermined pressure level.

26 . The method of claim 23 wherein:

decompressing the pressure chamber a second time comprises decompressing the pressure chamber a second time at a predetermined rapid depressurization rate by opening some but not all pressure valves to vent the pressure chamber; and

when the pressure in the pressure chamber has reached a predetermined purge pressure level that is less than the second predetermined pressure level, purging the pressure chamber by opening additional pressure valves to vent the pressure chamber and opening nozzles to provide a gas flow in the pressure chamber from the nozzles toward a sample collector.

27 . The method of claim 26 wherein:

the pressure chamber includes at least eight valves,

depressurizing the pressure chamber includes opening at least five valves; and

purging the pressure chamber includes opening at least three valves.

28 . A method for screening an item for prohibited materials, the method comprising:

placing an item in a pressure chamber;

pressurizing the pressure chamber a first time up to a first predetermined pressure level;

after pressurizing the pressure chamber the first time, decompressing the pressure chamber a first time at a predetermined rapid depressurization rate;

after decompressing the pressure chamber the first time, pressurizing the pressure chamber a second time substantially up to the predetermined pressure level;

after pressurizing the pressure chamber the second time, decompressing the pressure chamber a second time at a second predetermined rapid depressurization rate;

after decompressing the pressure chamber the second time, pressurizing the pressure chamber a third time up to a second predetermined pressure level, the second predetermined pressure level being a higher pressure level than the first predetermined pressure level;

after depressurizing the pressure chamber the third time, decompressing the pressure chamber a third time at a third predetermined rapid depressurization rate by opening some but not all pressure valves to vent the pressure chamber;

when the pressure in the pressure chamber has reached a predetermined purge pressure level that is less than the second predetermined pressure level and greater than the first predetermined pressure level, purging the pressure chamber by opening additional pressure valves to vent the pressure chamber and opening nozzles to provide a gas flow in the pressure chamber from the nozzles toward a sample collector;

collecting, from the sample collector, samples of substances removed from the item by the rapid decompressions and purge.