Methods and apparatus for visualising a print on an object
AssigneeThe Secretary of State for Defence
InventorsRoberto Stefano Pasquale King, Paul Francis Kelly, Steven Geoffrey Thorngate
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Abstract
The present invention provides a method for the production of a metal halide adduct of S4N4, in particular a specific copper adduct of S4N4, for the visualisation of a print on an object, in particular a fingerprint on a metal object. The present invention also provides a method and apparatus for visualising a print on an object, using S2N2 obtained from a metal halide adduct of S4N4.
Claims19
A method for production of a metal halide product of S4N4 comprising the steps of:
- a. reacting S2Cl2 with gaseous ammonia in a dry solvent to produce crude S4N4;
- b. without purification, adding the crude S4N4 to a solution of metal halide in alcohol and stirring until no S4N4 remains;
- and
- c. obtaining the metal halide product of S4N4 by removal of the alcohol.
A method for visualising a print on an object comprising
- a. placing within an apparatus:
- i. the object potentially comprising at least one print;
- and
- ii. a metal halide product of S4N4 produced by a process comprising:
- reacting S2Cl2 with gaseous ammonia in a dry solvent to produce crude S4N4;
- without purification, adding the crude S4N4 to a solution of metal halide in alcohol and stirring until no S4N4 remains;
- and
- obtaining the metal halide product of S4N4 by removal of the alcohol;
- b. heating the metal halide product of S4N4 under vacuum to produce S2N2 vapour;
- c. cooling the S2N2 vapour at or in proximity to the object to promote a phase change to solid S2N2;
- and
- d. heating the solid S2N2 back to S2N2 vapour to facilitate interaction of the S2N2 vapour with the object to visualise the print.
A method for visualising a print on an object comprising
- a. placing within an apparatus:
- i. the object potentially comprising at least one print;
- and
- ii. a metal halide product of S4N4;
- b. heating the metal halide product of S4N4 under vacuum to produce S2N2 vapour;
- c. cooling the S2N2 vapour at or in proximity to the object to promote a phase change to solid S2N2;
- and
- d. heating the solid S2N2 back to S2N2 vapour to facilitate interaction of the S2N2 vapour with the object to visualise the print.
Dependencies are inferred from the claim text.