A High Performance Direct Electron Imager

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The development of Transmission Electron Microscopes (TEM's) has made tremendous progress in the last few years and these instruments are now routinely used in laboratories across the world to obtain structural data from many materials at resolutions beyond 100pm. However the detectors that are essential for digital recording of images, diffraction patterns and spectra are still based on old technology which limits the performance of these instruments (the detector gap ). The basic problem lies in the construction and operation of detectors which are based on Charge Coupled Devices (CCD's) similar to those used for optical imaging. CCD's are damaged if directly exposed to the electron beam and must be coupled to a scintillator which converts the beam electrons into photons. These photons are then recorded by the CCD. Previous research under an EPSRC funded project has developed an entirely new type of sensor that can be directly exposed to medium energy electrons as an alternative to indirect detection. This sensor has been shown to have a far greater sensitivity than indirectly coupled CCDs (it is capable of detecting single electrons) and has far higher resolution. In addition it can be operated in a counting mode providing an infinite dynamic range. These significantly improved characteristics will enhance the output from TEM's by providing less noisy digital images and spectra enabling materials to be studied with less radiation exposure. This is vitally important when the TEM is used to study many modern materials, such as semiconductors, catalysts and carbon based nanostructures which are often damaged in the electron beam. It will also be critical for imaging biological materials which are extremely electron sensitive and where the enhanced sensitivity will be of considerable benefit. We now intend to develop the commercial potential of this novel the 1D sensor through the construction of a functional 2D imaging as a commercial prototype. This will require fabrication of a large array 2D sensor using our existing technology, the integration of suitable readout electronics and the design and construction of a suitable mechanical / vacuum interface to form a prototype imaging system. We will then use this to demonstrate to investors the clear advantages of this technology over existing detectors in a range of application examples from both biology and materials science. All of these steps have been demonstrated to be technically feasible within the orginal project and are essential steps in realising the commercial potential of the sensor.