R&D for Future 100 kton Scale Liquid Argon Detectors

Large liquid argon (LAr) detectors, up to 100 kton scale, are presently being considered for proton decay searches and neutrino astrophysics as well as far detectors for the next generation of long baseline neutrino oscillation experiments, aiming at neutrino mass hierarchy determination and CP violation searches in the leptonic sector. These detectors rely on the possibility of maintaining large LAr masses stably at cryogenic conditions with low thermal losses and of achieving long drifts of the ionization charge, so to minimize the number of readout channels per unit volume. Many R&D initiatives are being undertaken throughout the world, following somewhat different concepts for the final detector design, but with many common basic R&D issues.Comment: Contribution to the Workshop 'European Strategy for Future Neutrino Physics', CERN, Oct. 2009, to appear in the Proceeding

On particle production for high energy neutrino beams

Analytical formulae for the calculation of secondary particle yields in p-A interactions are given. These formulae can be of great practical importance for fast calculations of neutrino fluxes and for designing new neutrino beam-lines. The formulae are based on a parameterization of the inclusive invariant cross sections for secondary particle production measured in p-Be interactions. Data collected in different energy ranges and kinematic regions are used. The accuracy of the fit to the data with the empirical formulae adopted is within the experimental uncertainties. Prescriptions to extrapolate this parameterization to finite targets and to targets of different materials are given. The results obtained are then used as an input for the simulation of neutrino beams. We show that our approach describes well the main characteristics of measured neutrino spectra at CERN. Thus it may be used in fast simulations aiming at the optimisation of the proposed long-baseline neutrino beams at CERN and FNAL. In particular we will show our predictions for the CNGS beam from CERN to Gran Sasso.Comment: 18 pages, 10 figures. Submitted to The European Physics Journal

Feasibility of high-voltage systems for a very long drift in liquid argon TPCs

Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs.Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 201

Development and Longevity: Cellular and Molecular Determinants - A Mini-Review

Across species, development and longevity are tightly linked. We discuss the relevant literature and suggest that the root for this stringent relationship is the rate of development. The basis for the relationship between rate of development and longevity lies in adaptations that have occurred through evolution at multiple levels of biological complexity: organism, organ, cellular, and molecular. Thus, the analysis of the relationship is of interest for multiple fields of biology

Transient analysis and control of a heat to power conversion unit based on a simple regenerative supercritical CO2 Joule-Brayton cycle

Supercritical carbon dioxide (sCO(2)) heat to power systems are a promising technology thanks to their potential for high efficiency and operational flexibility. However, their dynamic behaviour during part-load and transient operation is still not well understood and further research is needed. Additionally, there is not enough literature addressing suitable control approaches when the objective is to follow the dynamics of heat load supplied by the topping process to maximise the power recovery. The current research aims to fill these gaps by proposing a one-dimensional transient modelling formulation calibrated against the major components of a 50 kW(e) sCO(2) test facility available at Brunel University London. The dynamic analysis showed that the system quickly adapts to a 2800s transient heat load profile, proving the flexible nature of the sCO(2) system investigated. The turbine bypass, during startup and shutdown modes of operation, enabled gradual and safe build-up/decline of the pressures and temperatures throughout the loop. The regulation of the inventory in the range 20-60 kg allowed a 30% variation of the turbine inlet temperature with lower penalties on system performance than the turbomachinery speed control. The designed proportional-integral inventory controller showed a rapid response in the control of the turbine inlet temperature around the set point of 773 K during large variations of the heat load

Beam intensity upgrade at Fermilab

The performance of the Fermilab proton accelerator complex is reviewed. The coming into operation of the NuMI neutrino line and the implementation of slip-stacking to increase the anti-proton production rate has pushed the total beam intensity in the Main Injector up to {approx} 3 x 10{sup 13} protons/pulse. A maximum beam power of 270 kW has been delivered on the NuMI target during the first year of operation. A plan is in place to increase it to 350 kW, in parallel with the operation of the Collider program. As more machines of the Fermilab complex become available with the termination of the Collider operation, a set of upgrades are being planned to reach first 700 kW and then 1.2 MW by reducing the Main Injector cycle time and by implementing proton stacking

Toward a framework for selecting behavioural policies: How to choose between boosts and nudges

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.In this paper, we analyse the difference between two types of behavioural policies – nudges and boosts. We distinguish them on the basis of the mechanisms through which they are expected to operate and identify the contextual conditions that are necessary for each policy to be successful. Our framework helps judging which type of policy is more likely to bring about the intended behavioural outcome in a given situation