Non-invasive single-bunch matching and emittance monitor

On-line monitoring of beam quality for high brightness beams is only possible using non-invasive instruments. For matching measurements, very few such instruments are available. One candidate is a quadrupole pick-up. Therefore, a new type of quadrupole pick-up has been developed for the 26 GeV Proton Synchrotron (PS) at CERN, and a measurement system consisting of two such pick-ups is now installed in this accelerator. Using the information from these pick-ups, it is possible to determine both injection matching and emittance in the horizontal and vertical planes, for each bunch separately. This paper presents the measurement method and some of the results from the first year of use, as well as comparisons with other measurement methods.Comment: 10 pages, 10 figures; added figure, minor textual additions; To be resubmitted to Phys. Rev. ST-A

ALTERNATIVE FUTURES OF RURAL AREAS IN THE EU: A COMPARATIVE ANALYSIS OF SCENARIO STUDIES

What does rural Europe look like in 2030? Is agriculture still the main land user? In recent years, studies such as ESPON, Eururalis, SCENAR2020, SENSOR, SEAMLESS and PRELUDE have tried to address these questions. These studies resulted in a number of alternative futures of rural areas in the EU. In this paper a comparative analysis of these scenario studies is made in order to explore differences and similarities in the scenarios and alternative futures of rural areas in the EU. For this purpose, we designed a scheme for assessing the properties of the various scenarios and a scheme for a systematic description of the rural futures according to the scenarios. It appears that most scenario studies use a baseline scenario and a set of alternative scenarios with different degrees of policy regulation. Agriculture will continue to be a main land user in 2030, although some land abandonment will take place.Rural Europe, scenario studies, alternative futures, land-use, territorial disparities, Agribusiness, Community/Rural/Urban Development, Research Methods/ Statistical Methods,

Structural basis of template-boundary definition in Tetrahymena telomerase.

Telomerase is required to maintain repetitive G-rich telomeric DNA sequences at chromosome ends. To do so, the telomerase reverse transcriptase (TERT) subunit reiteratively uses a small region of the integral telomerase RNA (TER) as a template. An essential feature of telomerase catalysis is the strict definition of the template boundary to determine the precise TER nucleotides to be reverse transcribed by TERT. We report the 3-Å crystal structure of the Tetrahymena TERT RNA-binding domain (tTRBD) bound to the template boundary element (TBE) of TER. tTRBD is wedged into the base of the TBE RNA stem-loop, and each of the flanking RNA strands wraps around opposite sides of the protein domain. The structure illustrates how the tTRBD establishes the template boundary by positioning the TBE at the correct distance from the TERT active site to prohibit copying of nontemplate nucleotides

Mismatch between the PSB and CPS due to the present vertical recombination scheme

The production of the nominal LHC beam will deamand optimum emittance preservation between individual machines in the injection chain. The edge effects at the entry and exit of the bending magnets used for the vertical recombination of the four PS booster rings to the level of the CPS results in a small uncompensated, and for each ring different, mismatch. We present recent measurements of the mismatch done in the PSB measurement line

"Intelligent" Automatic Beam Steering and Shaping

The strategy for Automated Beam Steering and Shaping (ABS) in the PS complex is to use theoretical response matrices calculated from an optics database. The main reason for this is that it enforces a certain understanding of the machine optics. A drawback is that the validation of such a matrix can be a lengthy process. However, every time a correction is made using an ABS program, a partial measurement of the response matrix is effectively performed. Since the ABS programs are very frequently used, the full matrices could thus be measured on an almost daily basis, provided this information is retained. The information can be used in two ways. Either the program passively logs the data to be analysed off­line, or the information is directly fed back to the matrix, which makes the program 'learn' as it executes. The data logging provides a powerful machine debugging tool, since deviations between the measured and theoretical matrices can be traced back to incorrect optical parameters. The 'learning' mode ensures that the correction will always converge. Implementation details and simulation results are discussed