2,665 research outputs found
The FCC-ee Interaction Region Magnet Design
The design of the region close to the interaction point of the FCC-ee
experiments is especially challenging. The beams collide at an angle (+-15
mrad) in the high-field region of the detector solenoid. Moreover, the very low
vertical beta_y* of the machine necessitates that the final focusing
quadrupoles have a distance from the IP (L*) of around 2 m and therefore are
inside the main detector solenoid. The beams should be screened from the effect
of the detector magnetic field, and the emittance blow-up due to vertical
dispersion in the interaction region should be minimized, while leaving enough
space for detector components. Crosstalk between the two final focus
quadrupoles, only about 6 cm apart at the tip, should also be minimized.Comment: Poster presented at IPAC16, May 8-13, Busan, Kore
Performance of Multi-Pixel Photon Counters for the T2K near detectors
We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino
detectors of T2K experiment. About 64,000 MPPCs have been produced and tested
in about a year. In order to characterize a large number of MPPCs, we have
developed a system that simultaneously measures 64 MPPCs with various bias
voltage and temperature. The performance of MPPCs are found to satisfy the
requirement of T2K experiment. In this paper, we present the performance of
17,686 MPPCs measured at Kyoto University.Comment: 15 pages, 14 figure
Retracted randomised controlled trials were cited and not corrected in systematic reviews and clinical practice guidelines
[Background and Objectives] To investigate whether and when the correction is done in Systematic Reviews (SRs) and Clinical Practice Guidelines (CPGs) when included Randomized Controlled Trials (RCTs) have been retracted. [Methods] In this meta-epidemiological study, we included SRs and CPGs citing the retracted RCTs from the Retraction Watch Database. We investigated how often the retracted RCTs were cited in SRs and CPGs. We also investigated whether and when such SRs and CPGs corrected themselves. [Results] We identified 587 articles (525 SRs and 62 CPGs) citing retracted RCTs. Among the 587 articles, 252 (43%) were published after retraction, and 335 (57%) were published before retraction. Among 127 articles published citing already retracted RCTs in their evidence synthesis without caution, none corrected themselves after publication. Of 335 articles published before retraction, 239 included RCTs that were later retracted in their evidence synthesis. Among them, only 5% of SRs (9/196) and 5% of CPGs (2/43) corrected or retracted their results. [Conclusion] Many SRs and CPGs included already or later retracted RCTs without caution. Most of them were never corrected. The scientific community, including publishers and researchers, should make systematic and concerted efforts to remove the impact of retracted RCTs
Design of beam optics for the Future Circular Collider e+e- -collider rings
A beam optics scheme has been designed for the Future Circular Collider-e+e-
(FCC-ee). The main characteristics of the design are: beam energy 45 to 175
GeV, 100 km circumference with two interaction points (IPs) per ring,
horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [1]
with local chromaticity correction. The crab-waist scheme is implemented within
the local chromaticity correction system without additional sextupoles, by
reducing the strength of one of the two sextupoles for vertical chromatic
correction at each side of the IP. So-called "tapering" of the magnets is
applied, which scales all fields of the magnets according to the local beam
energy to compensate for the effect of synchrotron radiation (SR) loss along
the ring. An asymmetric layout near the interaction region reduces the critical
energy of SR photons on the incoming side of the IP to values below 100 keV,
while matching the geometry to the beam line of the FCC proton collider
(FCC-hh) [2] as closely as possible. Sufficient transverse/longitudinal dynamic
aperture (DA) has been obtained, including major dynamical effects, to assure
an adequate beam lifetime in the presence of beamstrahlung and top-up
injection. In particular, a momentum acceptance larger than +/-2% has been
obtained, which is better than the momentum acceptance of typical collider
rings by about a factor of 2. The effects of the detector solenoids including
their compensation elements are taken into account as well as synchrotron
radiation in all magnets. The optics presented in this paper is a step toward a
full conceptual design for the collider. A number of issues have been
identified for further study
A High Luminosity e+e- Collider to study the Higgs Boson
A strong candidate for the Standard Model Scalar boson, H(126), has been
discovered by the Large Hadron Collider (LHC) experiments. In order to study
this fundamental particle with unprecedented precision, and to perform
precision tests of the closure of the Standard Model, we investigate the
possibilities offered by An e+e- storage ring collider. We use a design
inspired by the B-factories, taking into account the performance achieved at
LEP2, and imposing a synchrotron radiation power limit of 100 MW. At the most
relevant centre-of-mass energy of 240 GeV, near-constant luminosities of 10^34
cm^{-2}s^{-1} are possible in up to four collision points for a ring of 27km
circumference. The achievable luminosity increases with the bending radius, and
for 80km circumference, a luminosity of 5 10^34 cm^{-2}s^{-1} in four collision
points appears feasible. Beamstrahlung becomes relevant at these high
luminosities, leading to a design requirement of large momentum acceptance both
in the accelerating system and in the optics. The larger machine could reach
the top quark threshold, would yield luminosities per interaction point of
10^36 cm^{-2}s^{-1} at the Z pole (91 GeV) and 2 10^35 cm^{-2}s^{-1} at the W
pair production threshold (80 GeV per beam). The energy spread is reduced in
the larger ring with respect to what is was at LEP, giving confidence that beam
polarization for energy calibration purposes should be available up to the W
pair threshold. The capabilities in term of physics performance are outlined.Comment: Submitted to the European Strategy Preparatory Group 01-04-2013 new
version as re-submitted to PRSTA
Serum heart-type fatty acid-binding protein and cerebrospinal fluid tau: Marker candidates for dementia with Lewy bodies
Background: The measurement of biomarkers in cerebrospinal fluid (CSF) has gained increasing acceptance in establishing the diagnosis of some neurodegenerative diseases. Heart-type fatty acid-binding protein (H-FABP) was recently discovered in CSF and serum of patients with neurodegenerative diseases. Objective: We investigated H-FABP in CSF and serum alone and in combination with CSF tau protein to evaluate these as potential biomarkers for the differentiation between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). Methods: We established H-FABP and tau protein values in a set of 144 persons with DLB (n = 33), Parkinson disease with dementia (PDD; n = 25), AD (n = 35) and nonclemented neurological controls (NNC; n = 51). Additionally, serum H-FABP levels were analyzed in idiopathic Parkinson disease patients without evidence of cognitive decline (n = 45) using commercially available enzyme-linked immunosorbent assays. We calculated absolute values of HFABP and tau protein in CSF and serum and established relative ratios between the two to obtain the best possible match for the clinical working diagnosis. Results: Serum HFABP levels were elevated in DLB and PDD patients compared with NNC and AD subjects. To better discriminate between DLB and AD, we calculated the ratio of serum H-FABP to CSF tau protein levels. At the arbitrary chosen cutoff ratio >= 8 this quotient reached a sensitivity of 91% and a specificity of 66%. Conclusion: Our results suggest that the measurement of CSF tau protein, together with H-FABP quantification in serum and CSF, and the ratio of serum H-FABP to CSF tau protein represent marker candidates for the differentiation between AD and DLB. Copyright (c) 2007 S. Karger AG, Basel
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