Diamond Annual Review 2023/24

62 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 2 3 / 2 4 sensors in the tunnel, making it difficult to measure the effectiveness of the tunnel’s air handling system on a local level at the location of the girders and other components. This large-scale installation of additional temperature monitors into the Diamond tunnel can detect small, localised variations in air temperature of just 1/100 th of a degree centigrade (see Figure. 8). Better monitoring of local temperature stability in the storage ring will help to inform future FEA and modelling work done by Engineering, who are working to evaluate thermal stability of components like electron beam position monitors and girders. This data helps to estimate the likely stability of components for Diamond-II, which will ultimately be essential for estimating the electron beam and X-ray beam stability. Better monitoring also enables the potential testing of alternative tunnel cooling approaches that could help provide more stable temperatures. The system is designed to be flexible and has capacity to increase the number of sensors to investigate areas of interest in more detail. In addition, it is also designed to be compatible with Diamond-II so that it can be re-used after the accelerator upgrade. power supplies. Approximately 300 of the 1,300 installed cards were replaced during the year. The remaining 1,000 cards will be replaced during 2024/5. Measuring the synchrotron tunnel temperature inmore detail than ever before The Diamond electron beam can be as small as 4 µm in size vertically at the X-ray source points. If the electron beam moves, then the resulting X-ray beam will also move. We aim to keep the electron beam position stable to 10% of the beam size. For Diamond-II, these stability requirements are even more stringent. To achieve this, the ambient temperature in the tunnel must be finely controlled so that thermal expansion of components doesn’t impact X-ray beam stability. As part of the Diamond-II preparation work, a new network of over 260 temperature sensors has been installed in the synchrotron tunnel to help us better understand the temperature stability. Over the past sixmonths a project to install air temperature sensors located every two metres all the way around the synchrotron has been underway. Figure 7 shows the locations of the sensors in one accelerator cell. This project was completed in January 2024, in time to allow us to see the temperature of the storage ring throughout the first user run of the year in unprecedented detail. Before this installation, Diamond only had a handful of air temperature Figure 8. The change in temperatures during Run 1 2024 starting from a “cold” machine. The regularly spaced vertical bars correspond to Machine Development days. Figure 7. The location of the new temperature sensors in one accelerator cell. Figure 6. Replacement analogue-to-digital controller card.