30 research outputs found

    The NA48 LKr calorimeter digitizer electronics chain

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    The 13 500 channels of the NA48 liquid-krypton electromagnetic calorimeter readout electronics were put into operation in 1997. The digitizer electronics employs a new gain switching technique that expands the dynamic range of a standard 10-bit ADC to 14 bits at 40 MHz sampling rate employing a custom-developed integrated circuit (KRYPTON). The KRYPTON has been fabricated in 1.2 μm BiCMOS technology and was successfully developed together with industry on a short timescale. The performance and the experience from the first year of the operation of the liquid-krypton calorimeter electronics will also be briefly discussed

    The NA48 LKr calorimeter readout electronics

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    The NA48 experiment at the CERN SPS accelerator is making a measurement of the direct CP violation parameter ϵ/ϵ\epsilon'/\epsilon by comparing the four rates of decay of KSK_{S} and KLK_{L} into 2π02\pi^{0} and π+π\pi^{+}\pi^{-}. To reconstruct the decays into 2π02\pi^{0} the information from the almost 13500 channels of a quasi-homogeneous liquid krypton electromagnetic calorimeter is used. The readout electronics of the calorimeter has been designed to provide a dynamic range from a few MeV to about 50 GeV energy deposition per cell, and to sustain a high rate of incident particles. The system is made by cold charge preamplifiers (working at 120 degrees K), low-noise fast shapers followed by digitizer electronics at 40 MHz sampling rate that employs a gain switching technique to expand the dynamic range, where the gain can be selected for each sample individually (i.e. every 25 ns). To reduce the amount of data collected the system contains a zero suppression circuit based on halo expansion

    Symptomatic cytomegalovirus gastrointestinal infection with positive quantitative real-time PCR findings in apparently immunocompetent patients: a case series.

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    International audienceCytomegalovirus (CMV) gastrointestinal disease rarely occurs in immunocompetent patients, and is mainly diagnosed on the basis of histopathological findings. Real-time PCR for CMV DNA quantification is considered to be a useful diagnostic tool, but its place in the diagnostic strategy is not clearly defined. The goal of the study was to describe the clinical and paraclinical features of apparently immunocompetent patients with CMV gastrointestinal disease diagnosed according to quantitative PCR results. In this retrospective study conducted in a 1500-bed tertiary-care centre, we reviewed the case records of apparently immunocompetent patients with positive findings of CMV DNA in gastrointestinal biopsies with compatible symptoms and endoscopic findings. A total of 13 patients were included between January 2007 and December 2010. The median age was 81 years, and 54% of patients had underlying immune-modulating conditions. Diarrhoea, haematochezia and dysphagia were the main reported symptoms, and ulcers were the main endoscopic findings. The mean value of CMV DNA load in gastrointestinal biopsies was 3845 copies/μg total DNA (range, 15-15 500 copies/μg total DNA). The highest values were found in two patients who were diagnosed with adenocarcinoma in the subsequent course of CMV infection. Clinical features were similar to those in previous series in which diagnosis was based on histopathological analysis. Elderly people are more commonly affected, and a link with immune senescence is possible. Quantification of CMV DNA seems to be a useful tool for diagnosis when combined with clinical and endoscopic findings, but further studies are necessary to interpret quantitative values

    High rate large dynamic range analog circuitry and digitizers for fast calorimeter

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    This paper describes the issues encountered in the design of a large dynamic range digitizer for calorimetry. A gain switching technology developed for the liquid krypton calorimeter of the NA48 CP-violation experiment at CERN is described in detail. 14 bit dynamic range and better than 300 ps time resolution were achieved in beam tests with an 8 channel prototype. A mixed analog/digital ASIC has been developed. A 13,500 channel system is being produced which will be put into operation in 1996
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