Experimental observation of the improvement in MTF from backthinning a CMOS direct electron detector

McMullan, G.; Faruqi, A.R.; Henderson, Richard A.; Guerrini, N.; Turchetta, R.; Jacobs, Alan M.; Hoften, Gerald van

doi:10.1016/j.ultramic.2009.05.005

Cited by 102 publications

(56 citation statements)

References 19 publications

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“…In addition, these CMOS detectors can be made to be very thin (by backthinning after wafer fabrication), and this reduces the amount of energy deposited in the incorrect pixel of the detector by electrons backscattered from the substrate material, which also adds noise to the image. The modulation transfer function and DQE of a direct electron detector can be improved by a factor of two or more by backthinning (McMullan et al 2009c). The reduction of backscattering also results in a 2-to 3-fold improvement in detector lifetime due to reduced overall energy deposition.…”

Section: Direct Electron Cmos Detectorsmentioning

confidence: 99%

Single particle electron cryomicroscopy: trends, issues and future perspective

Vinothkumar

Henderson

2016

Quart. Rev. Biophys.

175

115

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Abstract. There has been enormous progress during the last few years in the determination of three-dimensional biological structures by single particle electron cryomicroscopy (cryoEM), allowing maps to be obtained with higher resolution and from fewer images than required previously. This is due principally to the introduction of a new type of direct electron detector that has 2-to 3-fold higher detective quantum efficiency than available previously, and to the improvement of the computational algorithms for image processing. In spite of the great strides that have been made, quantitative analysis shows that there are still significant gains to be made provided that the problems associated with image degradation can be solved, possibly by minimising beam-induced specimen movement and charge build up during imaging. If this can be achieved, it should be possible to obtain near atomic resolution structures of smaller single particles, using fewer images and resolving more conformational states than at present, thus realising the full potential of the method. The recent popularity of cryoEM for molecular structure determination also highlights the need for lower cost microscopes, so we encourage development of an inexpensive, 100 keV electron cryomicroscope with a high-brightness field emission gun to make the method accessible to individual groups or institutions that cannot afford the investment and running costs of a state-of-the-art 300 keV installation. A key requisite for successful high-resolution structure determination by cryoEM includes interpretation of images and optimising the biochemistry and grid preparation to obtain nicely distributed macromolecules of interest. We thus include in this review a gallery of cryoEM micrographs that shows illustrative examples of single particle images of large and small macromolecular complexes.

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Section: Direct Electron Cmos Detectorsmentioning

confidence: 99%

Single particle electron cryomicroscopy: trends, issues and future perspective

Vinothkumar

Henderson

2016

Quart. Rev. Biophys.

175

115

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“…Direct electron detection can be achieved by using solid state detection technology such as the Monolithic Active Pixel Sensor (MAPS) [1] or a hybrid technology such as the Medipix3 detector [2,3]. The MAPS detectors are well suited for high electron energy regime within the context of imaging performance, although at a substantial reduction in detection efficiency, as a high fraction of the electron beam is transmitted without being detected.…”

Section: Introductionmentioning

confidence: 99%

“…The MAPS detectors are well suited for high electron energy regime within the context of imaging performance, although at a substantial reduction in detection efficiency, as a high fraction of the electron beam is transmitted without being detected. Furthermore, at lower electron energies, the imaging performance using MAPS will be reduced due to increased electron backscattering [1]. Beam energies lower than 100 keV can provide greater contrast for thin biological samples [4] or the elimination of knock-on damage by the primary beam, for example in imaging 2-dimensional materials containing light elements such as graphene [5].…”

Section: Introductionmentioning

confidence: 99%

Using the Medipix3 detector for direct electron imaging in the range 60 keV to 200 keV in electron microscopy

et al. 2017

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ABSTRACT:Hybrid pixel sensor technology such as the Medipix3 represents a unique tool for electron imaging. We have investigated its performance as a direct imaging detector using a Transmission Electron Microscope (TEM) which incorporated a Medipix3 detector with a 300 µm thick silicon layer compromising of 256x256 pixels at 55 µm pixel pitch. We present results taken with the Medipix3 in Single Pixel Mode (SPM) with electron beam energies in the range, 60-200 keV. Measurements of the Modulation Transfer Function (MTF) and the Detective Quantum Efficiency (DQE) were investigated. At a given beam energy, the MTF data was acquired by deploying the established knife edge technique. Similarly, the experimental data required to DQE was obtained by acquiring a stack of images of a focused beam and of free space (flatfield) to determine the Noise Power Spectrum (NPS).

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“…Direct electron-detection devices, based on complementary metal-oxide-semiconductor transistors, have considerably improved the SNR relative to films or charge coupled devices [17]. The latter had to first convert the electronic signal to an optical signal, and then covert the optical signal back to an electronic signal.…”

Section: Resolution Improvementsmentioning

confidence: 99%

Cryo-electron microscopy for structural biology: current status and future perspectives

Wang

2015

Sci. China Life Sci.

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Recently, significant technical breakthroughs in both hardware equipment and software algorithms have enabled cryo-electron microscopy (cryo-EM) to become one of the most important techniques in biological structural analysis. The technical aspects of cryo-EM define its unique advantages and the direction of development. As a rapidly emerging field, cryo-EM has benefitted from highly interdisciplinary research efforts. Here we review the current status of cryo-EM in the context of structural biology and discuss the technical challenges. It may eventually merge structural and cell biology at multiple scales.cryo-electron microscopy, structural biology, cell biology, three-dimensional reconstruction Citation:Wang HW. Cryo-electron microscopy for structural biology: current status and future perspectives. Sci China Life Sci, 2015Sci, , 58: 750 -756, doi: 10.1007 Since the 1980s, structural biology has become a booming area in life sciences. By determining the three-dimensional (3-D) structures of proteins, nucleic acids, and their complexes, structural biology has given us accurate insights into concerning the shapes of complicated bio-macromolecules, the arrangements of atoms and molecules, and physical properties such as electro-potential distributions and hydrophobicity. These structures provide a crucial understanding of how bio-macromolecules execute specific biological functions. As techniques of structural biology become more mature in the 21st century, they assume more significant roles in various sub-disciplines of life sciences. Of the more than 10 5 protein structures that have been deposited in the Worldwide Protein Data Bank, most were solved by X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy ( Figure 1A). Recent technical progress has stimulated the use of new structural biology tools. In December 2013, two landmark Nature articles revealed the atomic-resolution structure of the TRPV1 ion channel in membranes that was imaged by cryo-EM [1,2]. With cryo-EM, Yifan Cheng and David Julius et al. [1,2] at the University of California, San Francisco, imaged for the first time the 3-D structure of the membrane channel protein TRVP1 with a resolution of 3.4 Å, and constructed an atomic model. In addition, several nearly atomic models of viruses, proteasomes, and ribosomes have been resolved by cryo-EM in the past few years [36]. The significance of the work was to obtain high-resolution structural information from a very small amount of sample, without requiring protein crystallization, and to simultaneously obtain the structures of the protein complex in different states over a relatively short time. In only one year, cryo-EM has received extensive attention as a means to directly obtain atomic structures of bio-macromolecules.Electron microscopy has been used in structural biology for many years. Since the 1950s, it has revealed cellular, sub-cellular, and bio-macromolecular structures. Based on completely different principles from X-ray crystallography and NMR spectroscopy in so...

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Experimental observation of the improvement in MTF from backthinning a CMOS direct electron detector

Cited by 102 publications

References 19 publications

Single particle electron cryomicroscopy: trends, issues and future perspective

Single particle electron cryomicroscopy: trends, issues and future perspective

Using the Medipix3 detector for direct electron imaging in the range 60 keV to 200 keV in electron microscopy

Cryo-electron microscopy for structural biology: current status and future perspectives

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