Emma Osbiston, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0DE R03: A Raspberry Pi Tomography Beamline controlled through Twitter In order to conduct experiments at Diamond Light Source, all of the beamlines utilise Diamond’s “Generic Data Acquisiton” software, GDA. This software allows the control of the experimental environment, by updating parameters such as the sample position, and collection of experimental data for analysis. In 2016 it was proven that GDA could run on a Raspberry Pi, a popular single-board computer the size of a credit card. This allowed the Raspberry Pi to conduct scans at the same software level as any other beamline at Diamond Light Source. For more information please visit www.diamond.ac.uk, www.twitter.com/diamondrpi or contact james.mudd@diamond.ac.uk 1. Introduction 5. Hardware & Scannables 6. Beamline Process 4. The API 3. Tomography Acknowledgments • An application programming interface (API) is a way of controlling communications between different softwares within a system – to the user, it will only accept specific inputs, and can return appropriate outputs. • To create the API used to control all of the devices and processes on the beamline, I used a development tool called Node-RED, which is a Raspberry Pi optimised visual interface for Node.js, an asynchronous, event-driven runtime for Javascript. The use of Node-RED required me to write functions in Javascript but greatly simplified the process compared with if I had used Node.js alone. Flows are stored in JSON format meaning to best view them Node-RED is needed (see the Github link below). Once a scan is requested via Twitter, Node-RED can then either choose to store or work with this information in Javascript; sample number is found through parsing the tweet string. This information is then passed through a flow of processes which can be seen in section six of this poster, with Node-RED controlling all of the communication between the processes. the outputs are 3D models, but with no internal features visible, as the light was not able to penetrate through the material to view it. The turntable is used to rotate the sample to different orientations, and these orientations are all captured as 2D images by the camera. Savu is the part of the process that takes these 2D images and converts them into a 3D tomogram. (Image by Dtrx used under Creative Commons Attribution-Share Alike 3.0 Germany License) Tomography is an imaging method that uses 2D images to build up a 3D model of a sample. By taking images of a sample using a penetrating light source (X-rays at Diamond) at different orientations, these can be spliced together using a mathematical procedure called tomographic reconstruction to give a 3D rendering of both the interior and exterior structure of the sample. As R03 uses visible light, the beam cannot penetrate the samples, meaning that the reconstructions are more of a demonstration of tomography than real tomography – 7. Conclusions • I would like to thank my supervisor James Mudd, as well as Peter Holloway, Mark Basham and Jacob Filik and the rest of the Data Acquisition Team for all their help and invaluable contributions. • Thanks to Ben Seeley, who wrote the initial configuration for GDA for RPi in 2016 and provided the starting point for this project. • Thanks also to Sam Elford, for creating custom parts for the project. • Finally I’d like to say thank you to everyone at Diamond Light Source who helped me with this project in numerous different ways. • The R03 beamline successfully demonstrates some of the processes used to conduct experiments on beamlines at Diamond Light Source • It is able to run beamline software from the main branch that aptly demonstrates the flexibility of the software, particularly GDA, which controls the hardware. • The Twitter interface works as an effective outreach tool. • It may be beneficial to split the processing across multiple Raspberry Pis as processes su