A Thin-Film Sensor System for Dual-Phase Explosives Detection

Iain Campbell
Saturday 13 June 2015



Welcome to St Andrews! Welcome to the leadership weekend! Welcome to the school of physics and astronomy! Welcome Iain, I hope you enjoy your internship!  If it wasn’t for all of the kind people we meet I’m sure we would feel well out of our depths.  Last week was a week of welcomes, of induction and one of learning and research for me.

Above is shown an example of the sorts of things I’ve been looking at recently, this is the hardware and software design part of the project and I’ll be showing it to my supervisors on Monday to ask for some advice on these preliminary designs.

This is my shot at trying to build an inexpensive measurement instrument capable of recognising hazardous chemicals such as explosives amongst various distractants such as diesel and fertiliser.  Most current devices used in this type of detection require significant sample preparation before measurement but here we are trying to build something which can be used in the field.

There is an array of fluorescent films inside this device, these are excited to fluoresce by an LED (light emitting diode) array.  When the analyte is incident on these films their light emission is ‘quenched’, the camera shown above monitors the intensity of the film and transduces this signal into an electrical signal which is then processed in the Raspberry Pi device shown.  We have tested the instrument for gaseous sensing but now need to update the films and the instrument to work in an aqueous environment.

I have also spent some time in a clean room (where the films are made) which required me to dress up in a suit, mask, gloves, boots and hairnet!  It was a bit stuffy in there but is required to produce high quality work.  I’ll be paying close attention because after next weeks mentoring has finished I’ll be in there myself to fabricate these films!

Wishing you a’ the best,



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