Autonomic Management of Large Clusters and Their Integration into the Grid

We present a framework for the co-ordinated, autonomic management of multiple clusters in a compute center and their integration into a Grid environment. Site autonomy and the automation of administrative tasks are prime aspects in this framework. The system behavior is continuously monitored in a steering cycle and appropriate actions are taken to resolve any problems. All presented components have been implemented in the course of the EU project DataGrid: The Lemon monitoring components, the FT fault-tolerance mechanism, the quattor system for software installation and configuration, the RMS job and resource management system, and the Gridification scheme that integrates clusters into the Grid

Quasi-free Pi0 and Pi- electroproduction on 4He in the Delta-resonance region (Pi en Delta in symbolen) - Zie als voorbeeld titelblad -

The reactions 4He(e, e' p3He)pi- and 4He(e, e' p3He)pi0 were studied simultaneously, and for the first time, in a large kinematical domain including the Delta-resonance region. This was achieved by detecting the recoiling 3He and 3H nuclei instead of the emitted pions. The dependences of the cross section on the recoil momentum p(rec), the invariant mass WpiN, and the direction thetapi,q' and phipi,q' of the produced pion, are globally well described by the results of (quasifree) distorted-wave impulse approximation calculations. However, in the Delta-resonance region there are clear discrepancies, which point to medium modifications of the Delta in 4He.Middelkoop, G. van [Promotor]Blok, H.P. [Copromotor]Hesseling, W. [Copromotor

A recoil detector for the internal target facility of AmPS (NIKHEF).

A recoil detector has been built for internal target experiments with the Amsterdam Pulse Stretcher and storage ring, AmPS, of NIKHEF. The detector was designed to detect low-energy (1-20 MeV/nucleon) and low-mass (A ≤ 4) recoiling nuclei emerging from electron-induced reactions. The detector consists of a low-pressure, two-step avalanche chamber, two layers of silicon strip detectors of 100 and 475 μm thickness and a scintillator. The signals from the separate detector elements are processed by custom-made analog electronics and dedicated VME-based digitizer modules. The detector was operated successfully at the AmPS electron scattering facility with a gaseous He target of 1

Four ways to determine the electron density in low-temperature plasmas

Four ways to measure the electron density in low-temperature plasmas are presented: Thomson scattering, Langmuir probe, optical-emission spectroscopy, and continuum-radiation analysis. The results of the four methods are compared to each other and discussed. For the electron-density range of 1019–1021 m−3, Thomson scattering proved to give the most accurate results (within a few percent); the Langmuir-probe measurements also proved acceptable (25%). A collisional-radiative-model fit through excited-level populations and continuum analysis yields results in good agreement with Thomson scattering data, although with larger margins of error (around 40%). A simple Saha fit proved to be inadequate