title: Photon counting imaging with an electron-bombarded CCD: towards a parallel-processing photoelectronic time-to-amplitude converter.
abstract: We have used an electron-bombarded CCD for optical photon counting imaging. The photon event pulse height distribution was found to be linearly dependent on the gain voltage. We propose on this basis that a gain voltage sweep during exposure in an electron-bombarded sensor would allow photon arrival time determination with sub-frame exposure time resolution. This effectively uses an electron-bombarded sensor as a parallel-processing photoelectronic time-to-amplitude converter, or a two-dimensional photon counting streak camera. Several applications that require timing of photon arrival, including Fluorescence Lifetime Imaging Microscopy, may benefit from such an approach. A simulation of a voltage sweep performed with experimental data collected with different acceleration voltages validates the principle of this approach. Moreover, photon event centroiding was performed and a hybrid 50% Gaussian/Centre of Gravity + 50% Hyperbolic cosine centroiding algorithm was found to yield the lowest fixed pattern noise. Finally, the camera was mounted on a fluorescence microscope to image F-actin filaments stained with the fluorescent dye Alexa 488 in fixed cells.
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors.forename: Liisa M
authors.initials: LM
authors.lastname: Hirvonen
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Jiggins
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sergent
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Zanda
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors.forename: Klaus
authors.initials: K
authors.lastname: Suhling