Characterisation of the Medipix3 detector for 60 and 80 keV electrons

In this paper we report quantitative measurements of the imaging performance for the current generation of hybrid pixel detector, Medipix3, used as a direct electron detector. We have measured the modulation transfer function and detective quantum efficiency at beam energies of 60 and 80 keV. In single pixel mode, energy threshold values can be chosen to maximize either the modulation transfer function or the detective quantum efficiency, obtaining values near to, or exceeding those for a theoretical detector with square pixels. The Medipix3 charge summing mode delivers simultaneous, high values of both modulation transfer function and detective quantum efficiency. We have also characterized the detector response to single electron events and describe an empirical model that predicts the detector modulation transfer function and detective quantum efficiency based on energy threshold. Exemplifying our findings we demonstrate the Medipix3 imaging performance recording a fully exposed electron diffraction pattern at 24-bit depth together with images in single pixel and charge summing modes. Our findings highlight that for transmission electron microscopy performed at low energies (energies <100 keV) thick hybrid pixel detectors provide an advantageous architecture for direct electron imaging

High resolution electron microscopic studies of colloidal metal particles

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Validity and Reliability of the Ergomo (R) pro Powermeter

The aim of this investigation was to assess the validity and reliability of the Ergomo (R) pro powermeter. Nine participants completed trials on a Monark ergometer fitted with Ergomo (R) pro and SRM powermeters simultaneously recording power output. Each participant completed multiple trials at power Outputs ranging from 50 to 450 W. The work stages recorded were 60 s in duration and were repeated three times. Participants also completed a single trial on a cycle ergometer designed to assess bilateral contributions to work Output (Lode Excaliber Sport PFM). The power output during the trials was significantly different between all three systems, (p<0.01) 231.2 +/- 114.2W, 233.0 +/- 112.4W, 227.8 +/- 108.8W for the Monark, SRM and Ergomo (R) pro system, respectively. When the bilateral contributions were factored into the analysis, there were no significant differences between the powermeters (p = 0.58). The reliability of the Ergomo (R) pro system (CV%) was 2.31% (95% CI 2.13-2.52%) compared to 1.59% (95% CI 1.47 to 1.74%) for the Monark, and 1.37% (95% CI 1.26-1.50%) for the SRM powermeter. These results indicate that the Ergomo (R) pro system has acceptable accuracy under these conditions. However, based on the reliability data, the increased variability of the Ergomo (R) pro system and bilateral balance issues have to be considered when using this device