The closed orbit measurement system for the CERN Antiproton Decelerator

The closed-orbit measurement system for the new Antiproton Decelerator (AD) employs 59 electrostatic pick-ups (PU). The intensity range from 2·1010 down to 107 particles poses challenging demands on the dynamic range and noise of the head amplifier. A low noiseamplifier has been developed, having an equivalent input noise of 0.6nV/√(Hz), allowing beam positions to be measured to ±0.5 mm with 5·106 particles. Two different gains take care of the large dynamic range. After amplification and multiplexing, the PU signals are fed to a network analyser, where each measurement point corresponds to one PU. The network analyser is phase locked to the RF of the AD, thus acting as a “tracking filter” instrument. An orbit measurement takes from 0.2 to 12 s depending on the IF-bandwidth of the network analyser, selected according to the beam intensity, and the precision required. At the end of the network analyser sweep the data are read via a GPIB interface and treated by a real-time task running in a VME based Power PC

Longitudinal coupled-bunch instability around 1 GHZ at the CERN PS booster

The fast-growing "Ring 4" instability occurring at intensities above 6.5 1012 protons in the top one of the four rings of the CERN PS Booster (PSB) is finally explained by an asymmetry in the 40 vacuum pump manifolds common to all rings. Impedance measurements (by wire method) and numerical calculations show a sharp resonant peak (Q~2000) at 1100 MHz and shunt impedances two times higher for the Ring 4 ports as compared to the other rings. This factor is sufficient to explain that the threshold of the instability falls below the maximum intensity only in Ring 4. A final, but labor-intensive and expensive, cure consists of inserting short-circuiting sleeves into all 160 beam ports. Results of beam and impedance measurements and the planned cure will be presented and discusse

Actinobaculum schaalii, a Common Uropathogen in Elderly Patients, Denmark

This organism is identified more often by PCR than by cultivation

Beam Measurement Systems for the CERN Antiproton Decelerator (AD)

The new, low-energy antiproton physics facility at CERN has been successfully commissioned and has been delivering decelerated antiprotons at 100 MeV/c since July 2000. The AD consists of one ring where the 3.5 GeV/c antiprotons produced from a production target are injected, rf manipulated, stochastically cooled, decelerated (with further stages involving additional stochastic and electron cooling and rf manipulation) and extracted at 100 MeV/c. While proton test beams of sufficient intensity could be used for certain procedures in AD commissioning, this was not possible for setting-up and routine operation. Hence, special diagnostics systems had to be developed to obtain the beam and accelerator characteristics using the weak antiproton beams of a few 10E7 particles at all momenta from 3.5 GeV/c down to 100 MeV/c. These include systems for position measurement, intensity, beam size measurements using transverse aperture limiters and scintillators and Schottky-based tools. This paper gives an overall view of these systems and their usage

Learning through 'prosuming': Insights from media literacy programmes in Asia

10.1177/097172180801300205Science, Technology and Society132259-27

Commissioning and First Operation of the Antiproton Decelerator (AD)

The Antiproton Decelerator (AD) is a simplified source of antiprotons which provides low energy antiprotons for experiments, replacing four machines: AC (Antiproton Collector), AA (Antiproton Accumulator), PS and LEAR (Low Energy Antiproton Ring), shutdown in 1996. The former AC was modified to include deceleration and electron cooling. The AD started operation in July 2000 and has since delivered cooled beam at 100 MeV/c (kinetic energy of 5.3 MeV) to 3 experiments (ASACUSA, ATHENA and ATRAP) for 1500 h. The flux (up to 2.5´105pbars /s delivered in short pulses of 330 ns every 110 s) and the quality of the ejected beam are not far from the design specifications. A linear RF Quadrupole Decelerator (RFQD) was commissioned in November 2000 to post-decelerate the beam for ASACUSA from 5.3 MeV to about 15 keV. Problems encountered in converting the fixed energy AC into a decelerating machine will be outlined, and the present status of the AD, including the performance of the cooling systems and the special diagnostics to cope with beams of less than 107 pbars, will be reviewed. Possible future developments will be sketche

iTEC: conceptualising, realising and recognising pedagogical and technological innovation in European classrooms

Innovation, a complex concept, underpinned a four-year pan-European research project designed to increase the effective use of technology in school classrooms. This article revisits evaluation data collected during the project and explores the challenges of conceptualising, realising and researching ‘innovation’. The authors describe how innovation was conceptualised, highlighting key issues, not all of which could be resolved in the project. The development of an approach to support teachers to change their practices facilitated the realisation of innovation in the classroom. This approach, through which researchers and national pedagogical coordinators worked with teachers to develop their teaching and learning practices with technology in potentially innovative ways, is outlined. Case study data are then used to exemplify how teachers and other stakeholders applied this approach and how they perceived innovation in practice within their own countries. Through a discussion of these cases, the article highlights the challenge of defining innovation in different country settings and, in turn, the complexity of identifying its occurrence. It concludes by proposing the next steps for similar research endeavours