1,425 research outputs found
u-RANIA: a neutron detector based on \mu -RWELL technology
In the framework of the ATTRACT-uRANIA project, funded by the European
Community, we are developing an innovative neutron imaging detector based on
micro-Resistive WELL ( -RWELL) technology. The -RWELL, based on the
resistive detector concept, ensuring an efficient spark quenching mechanism, is
a highly reliable device. It is composed by two main elements: a readout-PCB
and a cathode. The amplification stage for this device is embedded in the
readout board through a resistive layer realized by means of an industrial
process with DLC (Diamond-Like Carbon). A thin layer of BC on the copper
surface of the cathode allows the thermal neutrons detection through the
release of Li and particles in the active volume. This technology
has been developed to be an efficient and convenient alternative to the He
shortage. The goal of the project is to prove the feasibility of such a novel
neutron detector by developing and testing small planar prototypes with readout
boards suitably segmented with strip or pad read out, equipped with existing
electronics or readout in current mode. Preliminary results from the test with
different prototypes, showing a good agreement with the simulation, will be
presented together with construction details of the prototypes and the future
steps of the project.Comment: Prepared for the INSTR20 Conference Proceeding for JINS
Aging measurements on triple-GEM detectors operated with CF4-based gas mixtures
We present the results of a global irradiation test of full size triple-GEM detectors operated with CF 4 -based gas mixtures. This study has been performed in the framework of an R&D activity on detectors for the innermost region of the first muon station of the LHCb experiment. The prototypes have been irradiated at the Calliope facility of the ENEA-Casaccia with a high intensity 1.25 MeV γ 60 Co source. After the irradiation test the detectors performances have been measured with X-rays and with a 3 GeV pion beam at CERN. A SEM analysis on several samples of the detectors has been performed to complete the understanding of the physical processes occurring in a GEM detector during a strong irradiation
Unprecedented studies of the low-energy negatively charged kaons interactions in nuclear matter by AMADEUS
The AMADEUS experiment aims to provide unique quality data of hadronic
interactions in light nuclear targets, in order to solve fundamental open
questions in the non-perturbative strangeness QCD sector, like the
controversial nature of the state, the yield of hyperon
formation below threshold, the yield and shape of multi-nucleon
absorption, processes which are intimately connected to the possible existence
of exotic antikaon multi-nucleon clusters. AMADEUS takes advantage of the
DANE collider, which provides a unique source of monochromatic
low-momentum kaons and exploits the KLOE detector as an active target, in order
to obtain excellent acceptance and resolution data for nuclear capture on
H, He, Be and C, both at-rest and in-flight. During the
second half of 2012 a successful data taking was performed with a dedicated
pure carbon target implemented in the central region of KLOE, providing a high
statistic sample of pure at-rest nuclear interactions. For the future
dedicated setups involving cryogenic gaseous targets are under preparation.Comment: 14 pages, 6 figure
Production and performance of LHCb triple-GEM detectors equipped with the dedicated CARDIAC-GEM front-end electronics
The production of the triple-GEM detectors for the innermost region of the first muon station of the LHCb experiment has started in February 2006, and is foreseen to be completed by the end of July. The final design of the detector and the construction procedure and tools, as well as the quality controls are defined. The performances of each detector, composed by two triple-GEM chambers equipped with dedicated CARDIAC-GEM front-end electronics, are studied with a cosmic ray telescope. The cosmic ray telescope has been set up including all the final off-detector components
Measurement of the strong interaction induced shift and width of the 1s state of kaonic deuterium at J-PARC
The antikaon-nucleon interaction close to threshold provides crucial
information on the interplay between spontaneous and explicit chiral symmetry
breaking in low-energy QCD. In this context the importance of kaonic deuterium
X-ray spectroscopy has been well recognized, but no experimental results have
yet been obtained due to the difficulty of the measurement. We propose to
measure the shift and width of the kaonic deuterium 1s state with an accuracy
of 60 eV and 140 eV respectively at J-PARC. These results together with the
kaonic hydrogen data (KpX at KEK, DEAR and SIDDHARTA at DAFNE) will then permit
the determination of values of both the isospin I=0 and I=1 antikaon-nucleon
scattering lengths and will provide the most stringent constraints on the
antikaon-nucleon interaction, promising a breakthrough. Refined Monte Carlo
studies were performed, including the investigation of background suppression
factors for the described setup. These studies have demonstrated the
feasibility of determining the shift and width of the kaonic deuterium atom 1s
state with the desired accuracy of 60 eV and 140 eV.Comment: 12 pages, 9 figure
Low energy kaon nuclei interaction studies at DAΦNE
A preliminar study of these kind of hadronic interactions is being done by the AMADEUS collabo- ration by analyzing the existent KLOE data
Potent Sensitisation of Cancer Cells to Anticancer Drugs by a Quadruple Mutant of the Human Deoxycytidine Kinase.
Identifying enzymes that, once introduced in cancer cells, lead to an increased efficiency of treatment constitutes an important goal for biomedical applications. Using an original procedure whereby mutant genes are generated based on the use of conditional lentivector genome mobilisation, we recently described, for the first time, the identification of a human deoxycytidine kinase (dCK) mutant (G12) that sensitises a panel of cancer cell lines to treatment with the dCK analogue gemcitabine. Here, starting from the G12 variant itself, we generated a new library and identified a mutant (M36) that triggers even greater sensitisation to gemcitabine than G12. With respect to G12, M36 presents an additional mutation located in the region that constitutes the interface of the dCK dimer. The simple presence of this mutation halves both the IC50 and the proportion of residual cells resistant to the treatment. Furthermore, the use of vectors with self-inactivating LTRs leads to an increased sensitivity to treatment, a result compatible with a relief of the transcriptional interference exerted by the U3 promoter on the internal promoter that drives the expression of M36. Importantly, a remarkable effect is also observed in treatments with the anticancer compound cytarabine (AraC), for which a 10,000 fold decrease in IC50 occurred. By triggering the sensitisation of various cancer cell types with poor prognosis to two commonly used anticancer compounds M36 is a promising candidate for suicide gene approaches
A facility to Search for Hidden Particles (SHiP) at the CERN SPS
A new general purpose fixed target facility is proposed at the CERN SPS
accelerator which is aimed at exploring the domain of hidden particles and make
measurements with tau neutrinos. Hidden particles are predicted by a large
number of models beyond the Standard Model. The high intensity of the SPS
400~GeV beam allows probing a wide variety of models containing light
long-lived exotic particles with masses below (10)~GeV/c,
including very weakly interacting low-energy SUSY states. The experimental
programme of the proposed facility is capable of being extended in the future,
e.g. to include direct searches for Dark Matter and Lepton Flavour Violation.Comment: Technical Proposa
Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV
Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected
by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the
form of an enhancement of pairs of like-sign charged pions with small four-momentum
difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source
is investigated, determining both the correlation radius and the chaoticity parameter. The
measured correlation radius is found to increase as a function of increasing charged-particle
multiplicity, while the chaoticity parameter is seen to decreas
Observation of an Excited Bc+ State
Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
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