Muon front end for the neutrino factory Rogers, C. T.; Stratakis, D.; Prior, G. ...
Physical review special topics. PRST-AB. 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.
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.
The double-differential production cross-section of positive pions, , measured in the HARP experiment is presented. The incident particles are 8.9 GeV/c protons directed onto a beryllium target with ...a thickness of 5% of a nuclear interaction length. The measured cross-section has a direct impact on the prediction of neutrino fluxes for the MiniBooNE and SciBooNE experiments at Fermilab. After cuts, 13 million protons on target produced about 96000 reconstructed secondary tracks which were used in this analysis. Cross-section results are presented in the kinematic range 0.75 GeV/c≤pπ≤ 6.5 GeV/c and 30 mrad≤θπ≤ 210 mrad in the laboratory frame.
The structural and thermal evolution of major low‐angle normal faults in the Colorado River extensional corridor has been a controversial topic since the pioneering studies of metamorphic core ...complexes in the early 1980s. We present new geo‐thermochronometry data from the Harquahala Mountains in west‐central Arizona to determine the timing of extension, displacement magnitude, and slip rates along the Eagle Eye detachment fault (EED) during large‐magnitude Miocene extension. Zircon and apatite (U‐Th)/He data (ZHe and AHe, respectively) from 31 samples along a ~55 km extension‐parallel transect indicate active slip along the EED occurred between ~21 ± 1 Ma and ~14 Ma. The spatial extent of ZHe ages and exhumation of the zircon partial retention zone indicated ~44 ± 2 km of total displacement, whereas lithologic similarity and identical U‐Pb ages between correlated footwall rocks in the Little Harquahala Mountains and breccia clasts at Bullard Peak in the NE Harcuvar Mountains indicated ~43–45 km of displacement across the EED. AHe and ZHe data indicated slip rates of ~6.7 + 7.8/−2.3 km/Myr, and ~6.6 + 7.1/−2.0 km/Myr, respectively, both consistent with the duration and displacement estimates. The EED initiated as a listric fault with an ~34 ± 9° dip that decreased to ~13 ± 5° below ~7 km depth. Secondary breakaway development and footwall exposure occurred by ~17 Ma, during active EED slip. Lithologic and geo‐thermochronometric offset constraints show excellent agreement and provided a rare opportunity to fully resolve the timing, rates, and total displacement magnitudes along a major continental detachment fault.
Key Points
Total displacement on the Eagle Eye detachment fault is ~44 ± 2 km
Apatite and zircon (U‐Th)/He slip rates along the Eagle Eye detachment are ~6.6 + 7.8/−2.3 km/Myr and ~6.6 + 7.1/−2.0 km/Myr, respectively
Active extension along the Eagle Eye detachment fault from ~21 ± 1 Ma to ~14 Ma
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