3,259 research outputs found
The AMS-02 Time of Flight System
The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to
the read out electronics and measures velocity, direction and charge of the
crossing particles. The first version of the detector (called AMS-01) has flown
in 1998 aboard of the shuttle Discovery for a 10 days test mission, and
collected about events. The new version (called AMS-02) will be
installed on the International Space Station and will operate for at least
three years, collecting roughly Cosmic Ray (CR) particles. The TOF
system of AMS-01 successfully operated during the test mission, obtaining a
time resolution of 120 ps for protons and better for other CR ions. The TOF
system of AMS-02 will be different due to the strong fringing magnetic field
and weight constraintsComment: 6 pages, 7 figures. Talk given at the ``First International
Conference on Particle and Fundamental Physics in Space'', La Biodola, Isola
d'Elba (Italy), 14 -- 19 May 2002. To be published by Nuclear Physics B -
Proceedings Supplement. Sep. 13, 2002: added "Conclusion" sectio
A new Low Gain Avalanche Diode concept: the double-LGAD
This paper describes the new concept of the double-LGAD. The goal is to
increase the charge at the input of the electronics, keeping a time resolution
equal or better than a standard (single) LGAD; this has been realized by adding
the charges of two coupled LGADs while still using a single front-end
electronics. The study here reported has been done starting from single LGAD
with a thickness of 25 \textmu{m}, 35 \textmu{m} and 50 \textmu{m}.Comment: arXiv admin note: text overlap with arXiv:2208.0571
Liver function following hepatitis C virus eradication by direct acting antivirals in patients with liver cirrhosis: data from the PITER cohort
Background: The development of direct-acting antivirals (DAA) for HCV has revolutionized the treatment of HCV, including its treatment in patients with HIV coinfection. The aim of this study was to compare the changes in liver function between coinfected and monoinfected patients with cirrhosis who achieved HCV eradication by DAA. Methods: Patients with pre-treatment diagnosis of HCV liver cirrhosis, consecutively enrolled in the multicenter PITER cohort, who achieved a sustained virological response 12 weeks after treatment cessation (SVR12) were analysed. Changes in Child-Pugh (C-P) class and the occurrence of a decompensating event was prospectively evaluated after the end of DAA treatment. Cox regression analysis was used to evaluate factors independently associated with changes in liver function following viral eradication. Results: We evaluated 1350 patients, of whom 1242 HCV monoinfected (median follow-up 24.7, range 6.8–47.5 months after viral eradication) and 108 (8%) HCV/HIV coinfected (median follow-up 27.1, range 6.0–44.6). After adjusting for age, sex, HCV-genotype, HBsAg positivity and alcohol use, HIV was independently associated with a more advanced liver disease before treatment (C-P class B/C vs A) (OR: 3.73, 95% CI:2.00–6.98). Following HCV eradication, C-P class improved in 17/20 (85%) coinfected patients (from B to A and from C to B) and in 53/82 (64.6%) monoinfected patients (from B to A) (p = 0.08). C-P class worsened in 3/56 coinfected (5.3%) (from A to B) and in 84/1024 (8.2%) monoinfected patients (p = 0.45) (from A to B or C and from B to C). Baseline factors independently associated with C-P class worsening were male sex (HR = 2.00; 95% CI = 1.18–3.36), platelet count < 100,000/μl (HR = 1.75; 95% CI 1.08–2.85) and increased INR (HR = 2.41; 95% CI 1.51–3.84). Following viral eradication, in 7 of 15 coinfected (46.6%) and in 61 of 133 (45.8%) monoinfected patients with previous history of decompensation, a new decompensating event occurred. A first decompensating event was recorded in 4 of 93 (4.3%) coinfected and in 53 of 1109 (4.8%) monoinfected patients (p = 0.83). Conclusions: Improvement of liver function was observed following HCV eradication in the majority of patients with cirrhosis; however viral eradication did not always mean cure of liver disease in both monoinfected and coinfected patients with advanced liver disease
A narrow band neutrino beam with high precision flux measurements
The ENUBET facility is a proposed narrow band neutrino beam where lepton
production is monitored at single particle level in the instrumented decay
tunnel. This facility addresses simultaneously the two most important
challenges for the next generation of cross section experiments: a superior
control of the flux and flavor composition at source and a high level of
tunability and precision in the selection of the energy of the outcoming
neutrinos. We report here the latest results in the development and test of the
instrumentation for the decay tunnel. Special emphasis is given to irradiation
tests of the photo-sensors performed at INFN-LNL and CERN in 2017 and to the
first application of polysiloxane-based scintillators in high energy physics.Comment: Poster presented at NuPhys2017 (London, 20-22 December 2017). 5
pages, 2 figure
Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization
The high precision measurement of the hyperfine splitting of the
muonic-hydrogen atom ground state with pulsed and intense muon beam requires
careful technological choices both in the construction of a gas target and of
the detectors. In June 2014, the pressurized gas target of the FAMU experiment
was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility.
The objectives of the test were the characterization of the target, the
hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope
and X-rays detectors made with high purity Germanium and Lanthanum Bromide
crystals. In this paper the experimental setup is described and the results of
the detector characterization are presented.Comment: 22 pages, 14 figures, published and open access on JINS
The ENUBET Beamline
The ENUBET ERC project (2016-2021) is studying a narrow band neutrino beam
where lepton production can be monitored at single particle level in an
instrumented decay tunnel. This would allow to measure and
cross sections with a precision improved by about one order of
magnitude compared to present results. In this proceeding we describe a first
realistic design of the hadron beamline based on a dipole coupled to a pair of
quadrupole triplets along with the optimisation guidelines and the results of a
simulation based on G4beamline. A static focusing design, though less efficient
than a horn-based solution, results several times more efficient than
originally expected. It works with slow proton extractions reducing drastically
pile-up effects in the decay tunnel and it paves the way towards a time-tagged
neutrino beam. On the other hand a horn-based transferline would ensure higher
yields at the tunnel entrance. The first studies conducted at CERN to implement
the synchronization between a few ms proton extraction and a horn pulse of 2-10
ms are also described.Comment: Poster presented at NuPhys2018 (London 19-21 December 2018). 4 pages,
3 figure
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