We describe a hybrid pixel array detector (EMPAD -electron microscope pixel array detector) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128 × 128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift 2 distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, aswell as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition (DAQ) system, and preliminary results from experiments with 80 to 200 keV electron beams.Key words: pixel array detector (PAD), STEM, high dynamic range, mixed mode pixel array detector (MMPAD), electron microscope pixel array detector (EMPAD)

Objective. Assess the Regional Extension Center (REC) program's progress toward its goal of supporting over 100,000 providers in small, rural, and underserved practices to achieve meaningful use (MU) of an electronic health record (EHR). Data Sources/Study Setting. Data collected January 2010 through June 2013 via monitoring and evaluation of the 4-year REC program. Study Design. Descriptive study of 62 REC programs. Data Collection/Extraction Methods. Primary data collected from RECs were merged with nine other datasets, and descriptive statistics of progress by practice setting and penetration of targeted providers were calculated. Principal Findings. RECs recruited almost 134,000 primary care providers (PCPs), or 44 percent of the nation's PCPs; 86 percent of these were using an EHR with advanced functionality and almost half (48 percent) have demonstrated MU. Eightythree percent of Federally Qualified Health Centers and 78 percent of the nation's Critical Access Hospitals were participating with an REC. Conclusions. RECs have made substantial progress in assisting PCPs with adoption and MU of EHRs. This infrastructure supports small practices, community health centers, and rural and public hospitals to use technology for care delivery transformation and improvement. Key Words. Health information technology, electronic health records, meaningful use, practice transformation, primary care providers Health information technology (health IT) is foundational to the pursuit of the three-part aim of achieving better care, better health, and reducing costs (Berwick, Nolan, and Whittington 2008;Buntin, Jain, and Blumenthal 2010). Despite the potential benefits of health IT, adoption of electronic health records (EHRs) has been slow (Blumenthal 2010). In 2008, only 8 percent of

Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-bypixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different chargeintegrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods <150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128×128 pixel array with (150 µm) 2 pixels.

Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and highresolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1  10 8 8-keV photons pixel À1 s À1 , and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1  10 10 photons mm À2 s À1 within an area of approximately 325 nm  603 nm. This was done without need of a beam stop and with a very modest attenuation, while 'still' images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

The routine atomic resolution structure determination of single particles is expected to have profound implications for probing structure–function relationships in systems ranging from energy-storage materials to biological molecules. Extremely bright ultrashort-pulse X-ray sources – X-ray free-electron lasers (XFELs) – provide X-rays that can be used to probe ensembles of nearly identical nanoscale particles. When combined with coherent diffractive imaging, these objects can be imaged; however, as the resolution of the images approaches the atomic scale, the measured data are increasingly difficult to obtain and, during an X-ray pulse, the number of photons incident on the 2D detector is much smaller than the number of pixels. This latter concern, the signal `sparsity', materially impedes the application of the method. An experimental analog using a conventional X-ray source is demonstrated and yields signal levels comparable with those expected from single biomolecules illuminated by focused XFEL pulses. The analog experiment provides an invaluable cross check on the fidelity of the reconstructed data that is not available during XFEL experiments. Using these experimental data, it is established that a sparsity of order 1.3 × 10−3 photons per pixel per frame can be overcome, lending vital insight to the solution of the atomic resolution XFEL single-particle imaging problem by experimentally demonstrating 3D coherent diffractive imaging from photon-sparse random projections.