The NA62 experiment at the European Organization for Nuclear Research (CERN) Super Proton Synchrotron (SPS) aims to measure the Branching Ratio of the very rare kaon decay K + → π + νν, collecting O ...(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K + → π + π 0 , decay. To suppress this background an efficient photo veto system is foreseen with the Liquid Krypton (LKr) Electromagnetic Calorimeter Level 0 (L0) trigger. The development of a high-performance as well as reliable digital data system addresses this issue providing a mean to have the right bandwidth and efficiency to transmit experimental data to and from the counting room. This paper describes the LKr L0 trigger system, with particular emphasis for what concerns a LVDS digital data link used inside the system. Some aspects relative to the test set-up implementation as well as protocol test used to evaluate and qualify the digital data system are also part of the paper.
The incidence of Kaposi's sarcoma (KS) is increased severalfold in individuals infected with human immunodeficiency virus-1 (HIV). Human herpesvirus 8 (HHV8) has also been implicated in KS. We ...investigated several factors that may determine the onset of KS, particularly HHV8 infection in individuals after becoming seropositive for HIV.
We studied 366 individuals belonging to different HIV-exposure categories (i.e., homosexual activity, intravenous drug use, and heterosexual contact) for whom a negative HIV serologic test and then a positive HIV serologic test were available within a 2-year period. HHV8 antibody testing was performed by use of an immunofluorescence assay on the first serum sample available after the first positive HIV test. Actuarial rates of progression of KS and of other acquired immunodeficiency syndrome (AIDS)-defining diseases were estimated by use of time-to-event statistical methods. All statistical tests were two-sided.
Twenty-one of the 366 study participants developed AIDS-related KS, and 83 developed AIDS without KS. One hundred forty (38.3%) participants had detectable anti-HHV8 antibodies. The actuarial progression rate to KS among persons co-infected with HIV/HHV8 was nearly 30% by 10 years after HIV seroconversion. Increasing HHV8 antibody titers increased the risk of developing KS (for seronegative versus highest titer 1:125 serum dilution, adjusted relative hazard RH = 51.82; 95% confidence interval CI = 6.08-441.33) but not of other AIDS-defining diseases (adjusted RH = 1.14; 95% CI = 0.72-1.80). HHV8-seropositive homosexual men compared with HHV8-seropositive participants from other HIV-exposure categories showed an increased risk of KS that approached statistical significance (adjusted RH = 6.93; 95% CI = 0.88-54.84).
Approximately one third of individuals co-infected with HIV/HHV8 developed KS within 10 years after HIV seroconversion. Progression to KS increased with time after HIV seroconversion. Higher antibody titers to HHV8 appear to be related to faster progression to KS but not to other AIDS-defining diseases.
This work aimed to compare real-time polymerase chain reaction (PCR) with the commercially available enzyme-linked fluorescent assay (ELFA) VIDAS ECOLI O157™ for detecting
Escherichia
coli
O157 in ...mincemeat. In addition, a PCR-based survey on Shiga-toxin-producing E. coli (STEC) in mincemeat collected in Italy is presented. Real-time PCR assays targeting the stx genes and a specific STEC O157 sequence (SIL
O157
, a small inserted locus of STEC O157) were tested for their sensitivity on spiked mincemeat samples. After overnight enrichment, the presence of STEC cells could be clearly determined in the 25 g samples containing 10 bacterial cells, while the addition of five bacteria provided equivocal PCR results with Ct values very close to or above the threshold of 40. The PCR tests proved to be more sensitive than the ELFA-VIDAS ECOLI O157™, whose detection level started from 50 bacterial cells/25 g of mincemeat. The occurrence of STEC in 106 mincemeat (bovine, veal) samples collected from September to November 2004 at five different points of sale in Italy (one point of sale in Arezzo, Tuscany, central Italy, two in Mantova, Lombardy, Northern Italy, and two in Bologna, Emilia-Romagna, upper-central Italy) was less than 1%. Contamination by the main STEC O-serogroups representing a major public health concern, including O26, O91, O111, O145, and O157, was not detected. This survey indicates that STEC present in these samples are probably not associated with pathogenesis in humans.
Performance of the NA62 RICH detector Pepe, M.; Aisa, D.; Anzivino, G. ...
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC),
2015-Oct.
Conference Proceeding
NA62 is the last generation kaon experiment at CERN SPS aiming to study the decay K + _ π + νν̅. The goal of the experiment is to measure the decay branching ratio (O(10 -10 )) with 10% accuracy, ...collecting about 100 K + → π + νν̅ events in three years of data taking and assuming a 10% signal acceptance. The NA62 detector must be able to reject background events from decay channels with branching ratios up to 10 orders of magnitude higher than the signal and with similar experimental signature. To this purpose, good Particle Identification (PID) and kinematic rejection are required. Precise timing is also needed to correctly associate the π + with the parent K + in a high rate environment. The key element of the PID in NA62 is the Ring Imaging CHerenkov detector (RICH) to identify π and μ in the momentum range between 15 and 35 GeV/c with a muon rejection factor better than 1%; it is also required to measure the pion arrival time with a precision better than 100 ps and the Cherenkov angle with a resolution better than 80 μ rad. Finally, it must provide a fast L0 trigger signal for charged particles. At the beginning of the NA62 pilot run, from mid October to mid December 2014, the RICH detector was completely installed and ready to take data. The installation details and the results on the detector performance will be presented together with preliminary results from the first NA62 physics run in 2015.
The Imaging X-Ray Polarimetry Explorer IXPE mission will perform polarization measures of 2-8 keV X-rays. Imaging, spectroscopy, and timing will complement this measurement for a comprehensive study ...of soft X-rays. The launch of the IXPE NASA small explorer mission to a low earth orbit is due late 2021. We designed a subsystem of the scientific payload, which has three identical telescopes based on the detector unit. The Gas Pixel Detector and its back-end electronics are the core of these units, performing data acquisition and processing, event sequencing, and on-line data compression. The back-end electronics processes the auto-triggered output of the detector of 300 photons per second with 30% of dead-time. A radiation-tolerant FPGA implements the electronics custom algorithms, including two digital serial interfaces with a central on-board computer. One interface is used for command and control of the unit, while the other for scientific data transmission. We also designed comprehensive test equipment to emulate the on-board computer and to operate the electronics. This equipment uses an FPGA on a VMEbus board as the electrical interface for the electronics, transferring data to a personal computer with dedicated software infrastructure. In this paper, we shall discuss the design process of the back-end electronics and the results of laboratory tests and measurements with X-ray sources.
A prospective study, of 1,198 individuals who seroconverted to human immunodeficiency virus (HIV) was conducted to estimate the incidence and determinants of herpes zoster and to determine whether ...herpes zoster can accelerate the progression to AIDS. Herpes zoster was diagnosed for 48 individuals (4%). After adjusting for the CD4 cell count, individuals acquiring HIV infection through sexual contact were more likely to have herpes zoster than were injection drug users (relative hazard, 1.50). The crude relative hazard of AIDS for individuals who had herpes zoster compared with those without herpes zoster was 2.44; the adjusted relative hazard was 1.08. After adjusting for the CD4 cell count, fever was the only specific characteristic of herpes zoster that was significantly associated with a more rapid progression to AIDS (relative hazard, 6.52). Data suggest that herpes zoster occurs more frequently in individuals acquiring HIV infection through sexual transmission. There was no evidence that herpes zoster per se is an independent cofactor of progression of HIV disease, although febrile episodes of herpes zoster may predict a faster progression to AIDS.
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