An EMCCD camera, designed from the ground up for extreme faint flux imaging, is presented. CCCP, the CCD Controller for Counting Photons, has been integrated with a CCD97 EMCCD from e2v technologies into a scientific camera at the Laboratoire d'Astrophysique Expérimentale (LAE), Université de Montréal. This new camera achieves sub-electron read-out noise and very low Clock Induced Charge (CIC) levels, which are mandatory for extreme faint flux imaging. Data gathered with the camera suggests that through enhanced manufacturing processes, which would avoid traps from being created, and with the help of the clock shapes producible with CCCP, the CIC generated during the vertical transfer could be virtually suppressed. The camera has been characterized in laboratory and used on the Observatoire du Mont Mégantic 1.6-m telescope. The performance of the camera is discussed and experimental data with the first scientific data are presented.
CCCP, a CCD Controller for Counting Photons, is presented. This new controller uses a totally new clocking architecture and allows to drive the CCD in a novel way. Its design is optimized for the driving of EMCCDs at up to 20MHz of pixel rate and fast vertical transfer. Using this controller, the dominant source of noise of EMCCDs at low flux level and high frame rate, the Clock Induced Charges, were reduced to 0.001 -0.0018 electron/pixel/frame (depending of the electron multiplying gain), making efficient photon counting possible. CCCP will be deployed in 2009 on the ESO NTT through the 3D-NTT 1 project and on the SOAR through the BTFI project.
EMCCDs are devices capable of sub-electron read-out noise at high pixel rate, together with a high quantum efficiency (QE). However, they are plagued by an excess noise factor (ENF) which has the same effect on photometric measurement as if the QE would be halved. In order to get rid of the ENF, the photon counting (PC) operation is mandatory, with the drawback of counting only one photon per pixel per frame. The high frame rate capability of the EMCCDs comes to the rescue, at the price of increased clock induced charges (CIC), which dominates the noise budget of the EMCCD. The CIC can be greatly reduced with an appropriate clocking, which renders the PC operation of the EMCCD very efficient for faint flux photometry or spectroscopy, adaptive optics, ultrafast imaging and Lucky Imaging. This clocking is achievable with a new EMCCD controller: CCCP, the CCD Controller for Counting Photons. This new controller, which is now commercialized by Nüvü camēras inc., was integrated into an EMCCD camera and tested at the observatoire du mont-Mégantic. The results are presented in this paper.
The preoperative procedure for treating peripheral arterial disease requires 3D mapping of the blood vessel of interest. Because the available technologies are costly and invasive, and have an iodizing effect, new 3D imaging systems are being developed from ultrasound scanning technology using a robot as the probe manipulator. The authors of this paper have designed a new parallel robot along these lines. In response to the great concern for safety generated by the use of robots in medicine, we present a new approach for static balancing to enhance the safety of the proposed robot. Because total balancing is not practical for this device, the approach we have chosen is an optimization based on the addition of torsion springs on the actuated and the passive revolute joints. The optimization consists of a sequence of objectives, which are met using a linear programming technique, since the equations of torques and forces are linear with respect to the unknown variables.
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