EPR NRF Core Equipment Bid

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Electron Paramagnetic Resonance (EPR) spectroscopy, also known as Electron Spin Resonance (ESR), is possibly the most powerful technique for characterisation of paramagnetic materials, i.e. that contain unpaired electrons. Unpaired electrons give rise to the magnetic and electronic properties of materials and often govern reactivity when present, hence understanding their environment and behaviour is important. Paramagnets are ubiquitous from biological processes to magnetic materials; hence EPR is an essential tool in physics, chemistry, materials and biological sciences.The EPSRC funds a National Research Facility (NRF) for EPR, located in the Photon Science Institute (PSI) at The University of Manchester (UoM), providing access to state-of-the art experimental techniques and expertise for the UK academic community. Crudely, there are two ways to do EPR spectroscopy: continuous wave (cw) EPR and pulsed EPR, which give complementary information. Pulsed EPR is a much higher resolution technique (allowing measurement of much weaker interactions involving the unpaired electron) and also gives access to time-resolved information. However, such experiments are often very slow, requiring long data collection to get acceptable signal-to-noise (e.g. due to low paramagnet concentration) and/or a wide range of experimental conditions (e.g. different applied magnetic fields, or timings of the experiment). It is common for an experiment on a single sample to last a week of continuous measurement. As a consequence, the two pulsed EPR spectrometers that the EPR NRF currently runs are by far and away the most over-subscribed pieces of instrumentation.There is currently a second EPR facility at the UoM, based in the Manchester Institute of Biotechnology (MIB), which houses a pulsed spectrometer that was commissioned in 2009. Here we are proposing to expand the capacity and capability of the EPR NRF by upgrading the MIB spectrometer and relocating and incorporating it into the NRF in the PSI. This upgrade and relocation will enhance the capacity for pulsed EPR in the NRF by 50% at minimal cost. Almost all pulsed EPR needs to be performed at low temperatures, requiring liquid helium cooling. Helium is an expensive and finite resource. The second part of the proposal is to install a closed-system cryogen-free cryostat to the upgraded instrument, allowing continuous measurement down to a base temperature of <2 K. This is lower than we can currently reach at X-band, which will enable study of a wider range of materials. It will also almost entirely remove the need for liquid helium in the NRF. The new complete spectrometer system will increase the capacity for pulsed EPR for all users of the NRF across the UK, including ECRs and doctoral students, and the new capability will widen the user base. Finally, the new kit will enable us to expand our regular training workshops because attendee numbers are limited by spectrometer access.To contact the National EPR Facility and Service, please email: epr@manchester.ac.uk