Muon front end for the neutrino factory Rogers, C. T.; Stratakis, D.; Prior, G. ...
Physical review special topics. Accelerators and beams,
04/2013, Letnik:
16, Številka:
4
Journal Article
Recenzirano
Odprti dostop
In the neutrino factory, muons are produced by firing high-energy protons onto a target to produce pions. The pions decay to muons and pass through a capture channel known as the muon front end, ...before acceleration to 12.6 GeV. The muon front end comprises a variable frequency rf system for longitudinal capture and an ionization cooling channel. In this paper we detail recent improvements in the design of the muon front end.
A gene cluster encoding enzymes involved in LPS O antigen biosynthesis was identified from the partial genome sequence of Francisella tularensis subsp. tularensis Schu S4. All of the genes within the ...cluster were assigned putative functions based on sequence similarity with genes from O antigen biosynthetic clusters from other bacteria. Ten pairs of overlapping primers were designed to amplify the O antigen biosynthetic cluster by PCR from nine strains of F. tularensis. Although the gene cluster was present in all strains, there was a size difference in one of the PCR products between subsp. tularensis strains and subsp. holarctica strains. LPS was purified from F. tularensis subsp. tularensis Schu S4 and the O antigen was shown by mass spectrometry to have a structure similar to that of F. tularensis subsp. holarctica strain 15. When LPS from F. tularensis subsp. tularensis Schu S4 was used to immunize mice that were then challenged with F. tularensis subsp. tularensis Schu S4, an extended time to death was observed.
The SNO+ detector main physics goal is the search for neutrinoless double-beta decay, a rare process which if detected, will prove the Majorana nature of the neutrinos and provide information on the ...absolute scale of the neutrino absolute mass. Additional physics goals of SNO+ include the study of solar neutrinos, anti-neutrinos from nuclear reactors and the Earth's natural radioactivity as well as Supernovae neutrinos. Located in the SNOLAB underground physics laboratory (Canada), it will re-use the SNO experiment infrastructure with the 12 m diameter spherical volume filled with 780 tons of Te-loaded liquid scintillator. A short phase with the detector completely filled with water has started at the end of 2016. It will be followed by a scintillator phase expected to start at the end of this year. Continual careful monitoring of the detector state such as its hardware configuration, slow control information, data handling and triggers is required to ensure the quality of the data taken. Several automatic checks have been put in place for that purpose. This information serves as input to higher level run selection tools that will ultimately perform a final decision on the goodness of a run for a given physics analysis.
Diffuse Intrinsic Pontine Gliomas (DIPGs) are deadly brain cancers in children for which there is no effective treatment. This can partly be attributed to preclinical models that lack essential ...elements of the in vivo tissue environment, resulting in treatments that appear promising preclinically, but fail to result in effective cures. Recently developed co-culture models combining stem cell-derived brain organoids with brain cancer cells provide tissue dimensionality and a human-relevant tissue-like microenvironment. As these models are technically challenging, we aimed to establish whether interaction with the organoid influences DIPG biology and thus warrants their use. To address this question DIPG24 cells were cultured with pluripotent stem cell-derived cortical organoids. We created “mosaic” co-cultures enriched for tumour cell-neuronal cell interactions versus “assembloid” co-cultures enriched for tumour cell-tumour cell interactions. Sequential window acquisition of all theoretical mass spectra (SWATH-MS) was used to analyse the proteomes of DIPG fractions isolated by flow-assisted cell sorting. Control proteomes from DIPG spheroids were compared with DIPG cells isolated from mosaic and assembloid co-cultures. This suggested changes in cell interaction with the external environment reflected by decreased gene ontology terms associated with adhesion and extracellular matrix, and increased DNA synthesis and replication, in DIPG24 cells under either co-culture condition. By contrast, the mosaic co-culture was associated with neuron-specific brahma-associated factor (nBAF) complex signalling, a process associated with neuronal maturation. We propose that co-culture with brain organoids is a valuable tool to parse the contribution of the brain microenvironment to DIPG tumour biology.
Measurements of the double-differential {pi}{sup {+-}} production cross section in the momentum range 100{<=}p{<=}800 MeV/c and angle range 0.35{<=}{theta}{<=}2.15 rad in proton-beryllium, ...proton-carbon, proton-aluminium, proton-copper, proton-tin, proton-tantalum, and proton-lead collisions are presented. The data were taken with the large-acceptance HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. Tracking and identification of the produced particles was performed by using a small-radius cylindrical Time Projection Chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross sections d{sup 2}{sigma}/(dpd{theta}) at six incident proton beam momenta 3, 5, 8, and 8.9 GeV/c (Be only) and 12 and 12.9 GeV/c (Al only). They are based on a complete correction of static and dynamic distortions of tracks in the HARP TPC, which allows the complete statistics of the collected data set to be used. The results include and supersede our previously published results and are compatible with these. Results are compared with the GEANT4 and MARS Monte Carlo simulation.
Using an 185-kg NaITl array, COHERENT has measured the inclusive electron-neutrino chargedcurrent cross section on 127I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at ...Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤ 50 MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of ${9.2}_{—1.8}^{+2.1}$ × 10—40 cm2. This corresponds to a value that is ~41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on 127I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be ${5.2}_{—3.1}^{+3.4}$ × 10—40 and ${2.2}_{—2.2}^{+3.5}$ × 10—40 cm2, respectively.
The central Sierra Madre Oriental in Mexico developed primarily in the Late Cretaceous to early Palaeogene as a thin-skinned fold belt above a décollement hosted in Jurassic evaporite. In some ...regions shortening transitioned to sub-décollement structural levels, resulting in thick-skinned uplifts such as the Potosí uplift in Nuevo León. Thick-skinned deformation in the Potosí uplift involved folding of sub-décollement strata into an NNW-trending anticlinorium, cleavage development, thrust and conjugate strike-slip faulting, and extension fractures associated with barite mineralization. These structures consistently record subhorizontal shortening, directed ~52-65° in the southern uplift, ~69-72° in the northern uplift. Palaeocene to mid-Eocene zircon (U-Th)/He cooling dates record the timing of exhumation associated with thick-skinned uplift and suggest a continuation of shortening rather than a separate tectonic event. Zircon (U-Th)/He dates across the southern Potosí uplift and the Aramberri uplift, ~50 km to the south, range from ~66-53 Ma, whereas dates in the northern part of the Potosí uplift range from ~49-44 Ma. We attribute the transition to thick-skinned shortening to the mechanical strengthening of a planar décollement as rheologically weak evaporite was evacuated beneath synclinal keels of detachment folds. Along-strike differences in timing of exhumation and shortening directions may relate to differences in mechanical stratigraphy. Thicker intervals of evaporite in the northern uplift allowed thin-skinned shortening to continue while the southern uplift transitioned to thick-skinned shortening as the evaporite décollement was exhausted. As a result, stress-strain trajectories in the northern uplift refracted clockwise during continued deformation. Our findings provide new insight into the structural evolution of the Potosí uplift and may provide a framework for studying other thick-skinned uplifts in the orogen, and more generally orogenic belts that record a transition in deformation styles during progressive shortening.
PDF
