126 research outputs found
Faint flux performance of an EMCCD
Thorough numerical simulations were run to test the performance of three
processing methods of the data coming out from an electron multiplying charge
coupled device (EMCCD), or low light level charge coupled device (L3CCD),
operated at high gain, under real operating conditions. The effect of read-out
noise and spurious charges is tested under various low flux conditions (0.001
event/pixel/frame < f < 20 events/pixel/frame). Moreover, a method for finding
the value of the gain applied by the EMCCD amplification register is also
developed. It allows one to determine the gain value to an accuracy of a
fraction of a percent from dark frames alone.Comment: 9 pages, 6 figures, to appear in SPIE conference proceedings vol
6276, "High Energy, Optical & Infrared Detectors for Astronomy II" Orlando FL
USA, 24-31 May 2006. Code is available at
http://www.astro.umontreal.ca/~odaigle/emcc
Distribution de la matière sombre dans les galaxies spirales
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal
CCCP: A CCD Controller for Counting Photons
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-NTT1
project and on the SOAR through the BTFI project.Comment: 10 pages, 10 figures, to appear in "Ground-based and Airborne
Instrumentation for Astronomy II" SPIE conference, Marseille, 23-28 June 200
Cryogenic VPH gratings for the CELT/TMT
Characterization of Volume Phase Holographic gratings at cryogenic temperatures have been conducted using a new test facility at Caltech. The new test bench includes a cryostat that allows large angles for incident and diffracted light. Gratings under tests are shielded from thermal background, and precisely and uniformly temperature controlled. Preliminary results are presented and show little temperature dependence of the efficiency function
A versatile wavelength-dependent spectrophotometer for efficiency measurements of CCD and cryogenic gratings
A user-friendly and automatic illuminator with adjustable wavelength and optical power has been developed to obtain precision quantum efficiency (QE) curves of astronomical CCD as well as optical transmission measurements for cryogenic holographic gratings and other optical components. Integrating commercial components with custom mechanical parts and control software, this equipment is able to illuminate a target with light of controlled intensity and wavelength. This facility is primarily intended for testing of Volume Phase Holographic (VPH) gratings at low temperature as well as obtaining CCD quantum efficiencies. A Labview control application runs on a desktop computer allowing full automation of the spectrophotometer. The apparatus includes a Quartz-Tungsten light source, neutral density filters, a monochromator, visible and near-infrared power meters, as well as collimating and focusing optics. Rotation mechanisms allow the characterization of gratings for all angles of diffractions. For CCD testing, network commands allow the facility to get raw images, compute and record QE curves for further detector characterization
- …