Transparency of 0.2% GdCl3 Doped Water in a Stainless Steel Test Environment

The possibility of neutron and neutrino detection using water Cerenkov detectors doped with gadolinium holds the promise of constructing very large high-efficiency detectors with wide-ranging application in basic science and national security. This study addressed a major concern regarding the feasibility of such detectors: the transparency of the doped water to the ultraviolet Cerenkov light. We report on experiments conducted using a 19-meter water transparency measuring instrument and associated materials test tank. Sensitive measurements of the transparency of water doped with 0.2% GdCl3 at 337nm, 400nm and 420nm were made using this instrument. These measurements indicate that GdCl3 is not an appropriate dopant in stainless steel constructed water Cerenkov detectors.Comment: 17 pages, 11 figures, corrects typos, changes formatting, adds error bars to figure

Tight--binding description of the quasiparticle dispersion of graphite and few--layer graphene

A universal set of third--nearest neighbour tight--binding (TB) parameters is presented for calculation of the quasiparticle (QP) dispersion of $N$ stacked $sp^2$ graphene layers ($N=1... \infty$) with $AB$ stacking sequence. The QP bands are strongly renormalized by electron--electron interactions which results in a 20% increase of the nearest neighbour in--plane and out--of--plane TB parameters when compared to band structure from density functional theory. With the new set of TB parameters we determine the Fermi surface and evaluate exciton energies, charge carrier plasmon frequencies and the conductivities which are relevant for recent angle--resolved photoemission, optical, electron energy loss and transport measurements. A comparision of these quantitities to experiments yields an excellent agreement. Furthermore we discuss the transition from few layer graphene to graphite and a semimetal to metal transition in a TB framework.Comment: Corresponding author: A. Gr\"uneis Tel.: +49 351 4659 519 e--mail: [email protected]

Fine-tuning the functional properties of carbon nanotubes via the interconversion of encapsulated molecules

Tweaking the properties of carbon nanotubes is a prerequisite for their practical applications. Here we demonstrate fine-tuning the electronic properties of single-wall carbon nanotubes via filling with ferrocene molecules. The evolution of the bonding and charge transfer within the tube is demonstrated via chemical reaction of the ferrocene filler ending up as secondary inner tube. The charge transfer nature is interpreted well within density functional theory. This work gives the first direct observation of a fine-tuned continuous amphoteric doping of single-wall carbon nanotubes

A low energy optimization of the CERN-NGS neutrino beam for a theta_{13} driven neutrino oscillation search

The possibility to improve the CERN to Gran Sasso neutrino beam performances for theta_{13} searches is investigated. We show that by an appropriate optimization of the target and focusing optics of the present CNGS design, we can increase the flux of low energy neutrinos by about a factor 5 compared to the current tau optimized focalisation. With the ICARUS 2.35 kton detector at LNGS and in case of negative result, this would allow to improve the limit to sin^22 theta_{13} by an order of magnitude better than the current limit of CHOOZ at Delta m^2 approximately 3 times 10^{-3} eV^2 within 5 years of nominal CNGS running. This is by far the most sensitive setup of the currently approved long-baseline experiments and is competitive with the proposed JHF superbeam.Comment: 19 pages, 8 figure

On the complementarity of Hyper-K and LBNF

The next generation of long-baseline experiments is being designed to make a substantial step in the precision of measurements of neutrino-oscillation probabilities. Two qualitatively different proposals, Hyper-K and LBNF, are being considered for approval. This document outlines the complimentarity between Hyper-K and LBNF.Comment: 5 pager

Initial report from the ICFA Neutrino Panel

In July 2013 ICFA established the Neutrino Panel with the mandate "To promote international cooperation in the development of the accelerator-based neutrino-oscillation program and to promote international collaboration in the development a neutrino factory as a future intense source of neutrinos for particle physics experiments". This, the Panel's Initial Report, presents the conclusions drawn by the Panel from three regional "Town Meetings" that took place between November 2013 and February 2014. After a brief introduction and a short summary of the status of the knowledge of the oscillation parameters, the report summarises the approved programme and identifies opportunities for the development of the field. In its conclusions, the Panel recognises that to maximise the discovery potential of the accelerator-based neutrino-oscillation programme it will be essential to exploit the infrastructures that exist at CERN, FNAL and J-PARC and the expertise and resources that reside in laboratories and institutes around the world. Therefore, in its second year, the Panel will consult with the accelerator-based neutrino-oscillation community and its stakeholders to: develop a road-map for the future accelerator-based neutrino-oscillation programme that exploits the ambitions articulated at CERN, FNAL and J-PARC and includes the programme of measurement and test-beam exposure necessary to ensure the programme is able to realise its potential; develop a proposal for a coordinated "Neutrino RD" programme, the accelerator and detector R&D programme required to underpin the next generation of experiments; and to explore the opportunities for the international collaboration necessary to realise the Neutrino Factory.Comment: ICFA Neutrino Panel 2014(01