Bonfire night is held annually on the 5th November in the United Kingdom to celebrate the failed attempts of Guy Fawkes and his fellow conspirators in 1605, to assassinate King James I by blowing up the House of Lords. Following an anonymous tip, authorities discovered and arrested Fawkes in an undercroft directly below the first floor of the House of Lords, guarding 36 barrels of gunpowder, equating to approximately 1 metric tonne of explosives. The annual celebrations include firework displays, lighting of bonfires and the burning of Guy Fawkes effigies.
This year, Dr. Andrew Mathers (X-ray CT Project Manager) scanned a giant rocket firework to celebrate Bonfire Night.
X-ray CT enables us to non-destructively visualise the structure of the rocket and segment each of its components. The opaque 3D view shows the outer structure of the rocket, comprised of the plastic nose and base shell cones (rendered in blue), the central cardboard body (rendered in grey), the fuse safety cap (rendered in red) and the wooden stick for stability and support (rendered in brown). The transparent 3D view shows the fuse (rendered in red), the lifting charge (rendered in green), the delay charge (rendered in gold) and the different pelleted pyrotechnic stars (rendered in blue and yellow) which burn brightly once ignited creating the lightshow.
The X-ray CT scan of the rocket was acquired at 45 µm voxel resolution and 110 Watts, using a Nikon C2 Large Envelope System (LES). The system houses three X-ray sources (a Nikon 450kV microfocus with rotating target, a Varian 450kV minifocus and a Nikon 225kV microfocus with interchangeable rotating and reflection targets) and two detectors (a Varex 1621 EHS flat panel and a Nikon curved linear diode array). For this scan the Nikon 225kV microfocus source with rotating target and Varex 1621 EHS flat panel configuration was used. Due to the high aspect ratio of the rocket, the scan was performed using X.Tend (Nikon’s advanced approach to helical CT) which provided much greater resolution than achievable with conventional circular CT whilst still enabling the entire height of the firework (450mm) to be captured in a single acquisition. For this scan the detector acquired 9950 projections at an exposure of 250 ms and a gain of 18 dB.
X-ray CT data was reconstructed in Nikon CT Pro 3D, using Nikon’s advanced helical CT reconstruction algorithm, which provides industry leading speed without compromising quality. The resultant 3D data was rendered and segmented in Volume Graphics Studio Max 3.4.