P. Ouvrier-Buffet

Cea Leti, Grenoble, Rhône-Alpes, France

Are you P. Ouvrier-Buffet?

Claim your profile

Publications (5)3.66 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A growing interest has recently been observed in high flux X-ray imaging detectors with energy discrimination or spectroscopy capabilities. In this study we evaluate the performances of energy sensitive CdTe and CdZnTe detectors for X-ray imaging at fluxes of up to 2 107 X/mm2/s in the 20-150 keV energy range. Linear array detectors made from 3 mm thick single CdTe or CdZnTe crystals have 16 pixels with an 800 in pitch. These detectors were coupled to an innovative custom-designed 16-channel fast spectroscopy front-end electronic circuit. For each channel, the signal is continuously digitized and a FPGA controls acquisition and reconstructs the energy spectra on 256 bins for each channel. The detector was tested under X-rays for fluxes in the 105 to 2 × 107 X/mm2/s range. The main problem encountered at such high fluxes is the multiplication of pile-up events that reduces count rate and degrades energy resolution. When a very short shaping time was used, dead time was lower than 50 ns, and an energy resolution of 11 keV full width at half maximum (FWHM) at 2 × 106 X/mm2 s and 20 keV (FWHM) at 107 X/mm2/ s was achieved. We also show imaging results that illustrate the interest of the spectral information provided by each pixel.
    IEEE Transactions on Nuclear Science 02/2013; 60(1):408-415. · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper aims to experimentally evaluate a new material multidimensional method for material identification using a new CdTe spectrometric detector. LETI has developed a 16-channel fast read-out system capable of taking spectrometric measurements at count rates of more than 10<sup>7</sup> counts/s. This read-out system was coupled to CdTe linear array pixel detectors. A multidimensional analysis of the measured spectra has been conducted to perform material identification. The results show a decrease in false detection rate by a factor of up to 2 compared to an optimized dual counting approach applied on the same spectrometric raw data. Compared to a sandwich detector, the false detection rate decreases by a factor of more than 3 for thin objects. As a rule, the paper quantitatively demonstrates the continuous increase in performance and robustness with the number of detector energy counters.
    IEEE Transactions on Nuclear Science 11/2011; · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents multi dimensional approaches for material identification applied on experimental X-ray measurements obtained with CdTe spectrometric detector. LETI has been developing a 16 channels fast read-out electronics capable to perform spectrometric measurements at count rates above 10<sup>7</sup> counts/s. The read-out electronics was coupled to CdTe linear array pixel detectors. A multidimensional analysis of the measured spectra has been developed to perform material identification. The results show a decrease of false detection rate by a factor up to 2 compared to an optimised dual counting approach applied on the same spectrometric raw data. Compared to a sandwich detector, the false detection rate is decreasing by a factor higher than 3 for thin objects. Generally, the paper demonstrates quantitatively the continuous performance and robustness increase with the number of detector energy channels.
    Nuclear Science Symposium Conference Record (NSS/MIC), 2010 IEEE; 12/2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The development of a novel energy resolved fast X-ray imaging detector is reported. The device is based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) detectors coupled to a custom designed 16-channel fast spectroscopy front-end electronic circuit. For each channel, a fast Analog to Digital Converter (ADC) continuously digitizes the signal from the detector pixel. A FPGA controls the acquisition and constructs the spectra on 256 energy bins for each channel. In this study, we measured the spectrometric performances with monochromatic X-rays from a synchrotron source at the European Synchrotron Radiation Facility (ESRF). We were able to acquire high-resolution pulse spectra for different X-ray energies and fluxes ranging from 10<sup>5</sup> to 2 10<sup>7</sup> photons.mm<sup>-2</sup>.s<sup>-1</sup>. An energy resolution of 15% at 50 keV (7.5 keV FWHM) was obtained at 10<sup>7</sup> photons.mm<sup>-2</sup>.s<sup>-1</sup>. Additionally, first X-ray images in counting mode obtained with a 16-channels linear detector module are shown.
    Nuclear Science Symposium Conference Record (NSS/MIC), 2009 IEEE; 12/2009
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new cadmium zinc telluride (CZT) portable spectrometric system called OMEGA has been developed at CEA/LETI for high-energy applications like spent fuel assay in response to needs in the nuclear industry. The unit has been designed to operate at room temperature under water. The CZT OMEGA system is based on a single 10×10×10 mm<sup>3</sup> CZT detector associated with a single electronics channel. To improve performance, the system incorporates several technologies including: an electrode design named the "Mixed" electrode which combines a noncontacting Frisch grid and the pixel field effect to obtain maximum sensitivity from the 10×10×10 mm<sup>3</sup> CZT detector, a single hybrid preamplifier designed to reduce noise, an electronics board configured to enhance count rate capabilities and finally, electron bi-parametric (BP) correction (pulse height corrected via measurement of rise time) to improve both energy resolution and detection efficiency. This paper reports the most recent results obtained with the CZT OMEGA spectrometric system at high energy (<sup>137</sup>Cs and <sup>152</sup>Eu sources) at both low and high count rate: spectrometric performance shows an energy resolution of 1% FWHM at 662 keV (0.8% at 1408 keV) from 1 kcps to 50 kcps, deteriorating to 2% FWHM at 200 kcps.
    IEEE Transactions on Nuclear Science 11/2005; · 1.22 Impact Factor