APPARATUS AND ASSOCIATED ACCESSORIES, METHODS AND USES FOR VISUALISING A PRINT ON AN OBJECT

Abstract

The invention relates to an apparatus for the visualisation of a print on an object, the apparatus comprising: a base comprising a heating element in thermal communication with a receptacle for storing an agent, a housing to provide a sealed chamber; and a port for applying a vacuum to, or releasing a vacuum from, the sealed chamber. The invention is particularly for the visualisation of a fingerprint such as a latent fingerprint. The invention also relates to a system incorporating the apparatus with a cartridge and agent, and associated methods and uses for visualising a print on an object.

Claims

1. A system for visualizing a print on an object, the system comprising: a) an apparatus comprising: i. a base defining a surface, the base comprising a first heating element in thermal communication with a receptacle, the receptacle protruding from the surface of the base and having a depth; ii. a housing adapted to contact the base to provide a sealed chamber; and iii. a port adapted to apply a vacuum to or release a vacuum from the sealed chamber; b) a cartridge having a length and designed to be, or suitable for being, inserted into the receptacle of the apparatus; and c) an amount of agent within the cartridge, wherein the agent is a metal halide of S.sub.4N.sub.4, wherein the receptacle comprises a heat conductive material, and the cartridge comprises a material that is (i) less heat conductive than the heat conductive material of the receptacle or (ii) an insulating material, such that, in use and when the cartridge is inserted into the receptacle and upon applying heat to the receptacle with the first heating element, a resultant thermal gradient is generated along the length of the cartridge.

2. A system according to claim 1, wherein the receptacle comprises metal and the cartridge comprises glass.

3. A system according to claim 1, wherein the length of the cartridge is at least 1.5 times the depth of the receptacle.

4. A system according to claim 1, wherein the agent is CuBr.Math.S.sub.4N.sub.4.

5. A system according to claim 1, wherein the base comprises a second heating element in thermal communication with the surface of the base.

6. A system according to claim 1, wherein the housing is connected to the apparatus by a moveable arm.

7. A system according to claim 1, wherein the first heating element and the receptacle are arranged substantially centrally on the base.

8. A system according to claim 1, wherein the apparatus comprises a control interface.

9. A system according to claim 1, wherein the cartridge comprises a sealing means adapted to seal the cartridge and to be removed prior to use.

10. A system according to claim 9, wherein the agent is pre-weighed and provided in the sealed cartridge.

11. A method for visualizing a print on an object using the system of claim 1, the method comprising the steps of: a) placing the cartridge containing the agent in the receptacle; b) arranging the object on or proximal to the base; c) placing the housing on the surface of the base to form a sealed chamber enclosing the object, cartridge and agent; d) removing air from the sealed chamber via the port to provide a vacuum; e) heating the agent in the cartridge via the first heating element to generate vapor within the sealed chamber; f) allowing the vapor to contact the object; g) releasing the vacuum via the port; h) removing the housing to allow for off-gassing; and i) removing the object for inspection and/or downstream image recording.

12. A method according to claim 11, wherein for step e) the agent is heated at a temperature of from about 160? C. to 200? C. for at least 30 seconds.

13. A method according to 11, wherein the base comprises a second heating element in thermal communication with the surface of the base and wherein the method further comprises heating the surface of the base with the second heating element for a period of time during at least one of steps d) to h) and/or prior to step d).

14. A method according to claim 13, wherein the second heating element is heated at a temperature of from about 25? C. to 160? C.

15. A method according to claim 11, wherein the vacuum is at a pressure of from about 1.33?10.sup.?6 Pa to about 133 Pa.

16. A method according to claim 11, wherein the method is performed within a fume hood.

17. A method according to claim 11, wherein at least one of steps c) to e) and steps g) to h) is controlled by a control interface.

18. A method according to claim 11, wherein the agent is CuBr.Math.S.sub.4N.sub.4.

19. Use of the system of claim 1, to visualize a print on an object.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0077] FIG. 1 shows a side perspective view of a laboratory scale apparatus of the invention;

[0078] FIG. 2 shows a side sectional view of the chamber and base of the apparatus;

[0079] FIG. 3 shows a side sectional view of the base of the apparatus; and

[0080] FIG. 4 shows a side perspective view of a heater pot of the apparatus.

DETAILED DESCRIPTION

[0081] As shown in FIG. 1 and FIG. 2, apparatus (1) comprises a circular base (2) made of stainless steel and providing a surface (2a), surrounded by a circular perimeter (3), and a transparent circular housing (4) made from glass and defining a housing edge (4a). The housing (4) has dimensions of approximately 201 millimetres in diameter by 200 mm millimetres in height and is shown placed on the perimeter section (3) to form a 6.5 litre-volume sealed chamber (5). The perimeter section (3) is made from rubber to assisting in forming an air-tight seal between the perimeter section (3) and the housing edge (4a). An object (not shown) comprising a print can be arranged on or proximal to the base (2) (for example on an object holder (not shown)) such that when the moveable housing (4) is arranged on the surface (2a), the object is enclosed within a sealed chamber. A vacuum port (6) is provided on the base (2) for applying a vacuum to or releasing a vacuum from the sealed chamber (5). In the centre of the base (2) is shown a protruding receptacle (7) formed by a heater pot (7a) (not shown) underneath a cover element (7b). The receptacle (7) has an opening (7c) capable of receiving a glass cartridge (not shown) containing CuBr.Math.S.sub.4N.sub.4.

[0082] Housing (4) is attached to the apparatus via moveable arm (8) to enable movement of the housing (4) from an open position to a closed position, the latter arrangement provides the sealed chamber (5). Operation of the apparatus, including the controlling the movement of the arm (8) and setting/initiating the programme settings when undertaking a method for visualising a print on an object, is achieved via user control interface (9) which is connected to a processor (not shown) located internally within the apparatus (1).

[0083] As shown in more detail in FIG. 3, the cover element (7b) attaches to the base (2) via an extended screw region (7c) which is alignable with a thread groove (2b). This arrangement ensures the heater pot (7a) is securely attached to the base (2) and in thermal communication with a first heating element (10a. 10b). The arrangement of the first heating element (10a, 10b) and receptacle (7), when used in combination with a glass cartridge (not shown), ensures a thermal gradient is provided in the cartridge during heating i.e. the cartridge would be hotter at its base and/or lower region (primarily where it contacts the heater pot (7a)), relative to the top and/or upper region of the cartridge. Heater pot (7a) sits in an indented region of (2c) of the base (2) to ensure closer orientation between the first heating element (10a, 10b) and lower region of the cartridge (not shown) when positioned in the heater pot (7a) during use. The cartridge may also provide for funnelling of the agent vapour.

[0084] Shown in FIG. 4 is a heater pot (7a) made of aluminium and comprising a silver anodise finish. The heater pot (7a) is 20 millimetres in diameter (19 millimetres in internal diameter to provide for tolerance of the cartridge) and 28.5 millimetres in height. The heater pot (7a) has an opening of 20 millimetres in depth for receiving the cartridge (not shown) of 17 millimetres internal diameter by 50 millimetres in height and containing CuBr.Math.S.sub.4N.sub.4. This arrangement ensures that, in use, the lower region of the cartridge of depth of 20 millimetres, including the CuBr.Math.S.sub.4N.sub.4 collected on the base of the cartridge, sits within the heater pot (7a), ensuring a direct thermal communication between first heating element (10a, 10b) and the lower region (including the base) of the cartridge due to thermal conduction and radiated heat. The upper region of the cartridge (i.e. approximately 30 millimetres in height) lies outside the receptacle (7) in use. Thus, the arrangement of the cartridge in the receptacle (7) (primarily the heater pot (7a)) ensures a thermal gradient, and/or funnelling, is provided across the cartridge such that unwanted S.sub.2N.sub.2 polymerisation is captured on the inner sides of the cartridge.

[0085] Located in a region of the base (2) between the protruding receptacle (7) and the circular perimeter (3) is an arrangement of a second heating element (11a, 11b, 11c, 11d) in thermal communication with the base surface (2a). The second heating element (11a, 11b, 11c. 11d) contributes to the quantity and uniformity of S.sub.2N.sub.2 vapour in the sealed chamber by ensuring that agent vapour does not cool on the surface (2a) of the base (2).

[0086] In use, apparatus (1) is operated in a fume hood and programmed/operated using the control interface (9). A cartridge containing CuBr.Math.S.sub.4N.sub.4 is placed in receptacle (7) of apparatus (1) to provide a system for visualising a print on an object. The seal is removed from the cartridge to enable S.sub.2N.sub.2 vapour to be released into the sealed chamber when the system is in use. For visualising a print on a copper-based object, the amount of CuBr.Math.S.sub.4N used is envisaged to be approximately 0.15 grams for a 6.5-litre volume chamber. For visualising a print on a stainless steel-based object, it is envisaged that 0.3 grams of CuBr.Math.S.sub.4N.sub.4 can be used for a 6.5-litre volume chamber.

[0087] After providing a sealed chamber (5) via operation of moveable arm (8), CuBr.Math.S.sub.4N.sub.4 is heated for about 1 minute, under a vacuum of about 13 Pa (0.1 mmHg) obtained via vacuum port (6), at a temperature to about 180? ? C. obtained via thermal communication with the first heating element (10a, 10b), to decompose the CuBr.Math.S.sub.4N.sub.4 and produce S.sub.2N.sub.2 vapour. The S.sub.2N.sub.2 enters the sealed chamber (5) and contacts the object comprising a print, while S.sub.2N.sub.2 by-products can accumulate on the inner sides of the cartridge as a result of the thermal gradient, and/or the funnelling, along the cartridge.

[0088] The sealed chamber (5) containing the object comprising a print to be visualised can be then left to develop for about 15 minutes. Fingerprint development is observed as S.sub.2N.sub.2 vapour polymerises on the object being treated. During this time, the second heating element (11a, 11b, 11c, 11d) is heated at about 50? ? C. to preventing crystallisation of S.sub.2N.sub.2 on the surface of the base (2) of the apparatus (1).

[0089] Upon completing the duration in which the S.sub.2N.sub.2 vapour contacts the object (2), the vacuum is removed from sealed chamber (5) via vacuum port (6) and, after releasing the housing (4) via moveable arm (8), the S.sub.2N.sub.2 vapour is removed via the fume hood.

[0090] Various modifications to the apparatus (1) can be made as will be apparent to those skilled in the art. For example, the size of the housing (2) can be varied in size and/or shape according to the desired application. For example, the housing can provide for a sealed chamber with a volume of 13 litres (i.e. having dimensions of approximately 201 millimetres in diameter by 400 millimetres in height, so therefore taller in orientation than the embodiment described for FIGS. 1-2). In this instance, it is envisaged that approximately 0.3 grams of CuBr.Math.S.sub.4N.sub.4 can be used for visualising a print on a copper-based object, while 0.6 grams of CuBr.Math.S.sub.4N.sub.4 can be used for visualising a print on a stainless steel-based object. A fan, such as a stirring fan, may be provided to assist with the dispersion of S.sub.2N.sub.2 vapour when the apparatus is used to implement the method of the invention for visualising a print on an object. The housing (4) may be rectangular or square in shape. The apparatus may also not require use of a cartridge, but the receptacle could be adapted to receive the agent and to provide the thermal gradient when heated, and/or the funnelling, such as the upper portion of the receptacle could extend beyond the heater pot (7a), and could for example comprise, or consist essentially, of a poor conductor of heat or an insulator, such as glass. Furthermore, a receptacle and/or cartridge of different size and/or shape may be envisaged, for example wherein in use, a different portion of the cartridge can protrude from the receptacle, in order to optimise the thermal gradient and/or the funnelling.

[0091] It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

[0092] Moreover, the invention has been described with specific reference to fingerprint visualisation. It will be understood that this is not intended to be limiting and the invention may be used more generally. For example, the invention may be used more generally in the forensic fields, and may be used in other chemical applications. Additional applications of the invention will occur to the skilled person.