Explosives screening on a vehicle surface

A system for detecting particles on a vehicle having an outer surface comprising:

• a housing including
• a wall capable of being placed in a test position adjacent to, but not in contact with, a portion of the outer surface of the vehicle;
• and
• an elongate sealing member fastened to said housing along a perimeter surrounding said wall, said elongate sealing member having a contact surface facing away from said wall, said contact surface contacting the outer surface of the vehicle to define a test volume when said wall is in said test position;
• a gas flow system comprising
• at least one gas inlet extending through said wall for providing a gas stream against the surface of the vehicle within the test volume;
• a gas outlet for gas to exit the test volume;
• and
• detector means for detecting the presence of particles in the gas passing through said gas outlet;
• wherein said sealing member comprises a hollow bellows having one end extending along the perimeter and an opposing end;
• said housing further comprising activating means for moving said opposing end of said bellows against the outer surface of the vehicle.