RF-Based Electron Beam Timing Measurement with Sub-10FS Resolution

Time of flight measurements of a relativistic electron beam have been performed and have demonstrated a resolution below 10 fs. The electronics consisted of a heterodyne receiver incorporating an array of analogue phase detectors in order to reduce noise. The performance of the system makes it suitable for the challenging requirements of intra-pulse train timing measurements in a future linear collider

The performance of phaselocked loops for frequency control in single sideband land mobile radio receivers.

SIGLELD:D49169/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

STATUS OF SUPERCONDUCTING CAVITIES IN LEP

ABSTRACT The upgrade of the Large Electron Positron collider (LEP) with superconducting cavities is nearing a successful completion. There are presently 240 superconducting cavities installed which, together with the original copper RF system, provide up to 2.6GV per turn. The majority of the superconducting cavities is of niobium sputtered on copper and runs at an operating gradient of 6MV/m. In 1997, LEP has operated routinely at an energy of 91.5GeV per beam and with a total current of over 5mA. The operation of the RF system has been very satisfactory, with only a few cavities limited in field. This paper will concentrate on describing the operation of this system during 1997, including new features, operational procedures and present limitations. Future plans, notably the work towards improving performance and the installation of the remaining cavities, will also be covered

Kinematic fault slip evolution source models of the 2008 M7.9 Wenchuan earthquake in China from SAR interferometry, GPS and teleseismic analysis and implications for Longmen Shan tectonics

The M_w 7.9 2008 Wenchuan earthquake ruptured about 280 km of faults in the Longmen Shan of Sichuan province, China, at the eastern edge of the Tibetan Plateau. We use teleseismic waveforms with geodetic data from Global Positioning System, synthetic aperture radar interferometry and image amplitude correlation to produce a source model of this earthquake. The model describes evolution of fault slip during the earthquake. The geodetic data constrains the spatial distribution of fault slip and the seismic waveforms constrain mostly the time evolution of slip. We find that the earthquake started with largely thrust motion on an imbricate system of faults beneath the central Longmen Shan, including the Beichuan Fault and Pengguan Fault, with fault slip at depth extending up to 50 km northwest of the mountain front. The fault ruptures continued northeast along the Beichuan Fault with more oblique slip (right-lateral and thrust) and the proportion of lateral motion increasing in the northern Longmen Shan. The northernmost fault segment has a much steeper dip, consistent with nearly pure strike-slip motion. The kinematic source model shows that the rupture propagated to the northeast at about 2.5–3.0 km s^(−1), producing a cascade of subevents with a total duration of about 110 s. The complex fault ruptures caused shortening and uplift of the extremely steep central Longmen Shan, which supports models where the steep edge of the plateau is formed by thrusting over the strong crust of the Sichuan Basin

Automatic conditioning of the CTF3 RF system

The RF system of CTF3 (CLIC Test Facility 3) includes ten 35 MW to 40 MW 3 GHz klystrons and one 20 MW 1.5 GHz klystron. High power RF conditioning of the waveguide network and cavities connected to each klystron can be extremely time consuming. Because of this, a fully automatic conditioning system has been developed within a CERN JINR (Dubna) collaboration. It involves relatively minor hardware additions, most of the work being in application and front-end software. The system has already been used very successfully

Personal Wellbeing Score (PWS)—a short version of ONS4: development and validation in social prescribing

Aims Our aim was to develop a short generic measure of subjective well-being for routine use in patient-centred care and healthcare quality improvement alongside other patient-reported outcome and experience measures. Methods The Personal Wellbeing Score (PWS) is based on the Office of National Statistics (ONS) four subjective well-being questions (ONS4) and thresholds. PWS is short, easy to use and has the same look and feel as other measures in the same family of measures. Word length and reading age were compared with eight other measures. Anonymous data sets from five social prescribing projects were analysed. Internal structure was examined using distributions, intra-item correlations, Cronbach’s α and exploratory factor analysis. Construct validity was assessed based on hypothesised associations with health status, health confidence, patient experience, age, gender and number of medications taken. Scores on referral and after referral were used to assess responsiveness. Results Differences between PWS and ONS4 include brevity (42 vs 114 words), reading age (9 vs 12 years), response options (4 vs 11), positive wording throughout and a summary score. 1299 responses (60% female, average age 81 years) from people referred to social prescribing services were analysed; missing values were less than 2%. PWS showed good internal reliability (Cronbach’s α=0.90). Exploratory factor analysis suggested that all PWS items relate to a single dimension. PWS summary scores correlate positively with health confidence (r=0.60), health status (r=0.58), patient experience (r=0.30) and age group (r=0.24). PWS is responsive to social prescribing intervention. Conclusions The PWS is a short variant of ONS4. It is easy to use with good psychometric properties, suitable for routine use in quality improvement and health services research

Bayesian inversion for finite fault earthquake source models – II: the 2011 great Tohoku-oki, Japan earthquake

We present a fully Bayesian inversion of kinematic rupture parameters for the 2011 M_w 9 Tohoku-oki, Japan earthquake. Albeit computationally expensive, this approach to kinematic source modelling has the advantage of producing an ensemble of slip models that are consistent with physical a priori constraints, realistic data uncertainties, and realistic but simplistic uncertainties in the physics of the kinematic forward model, all without being biased by non-physical regularization constraints. Combining 1 Hz kinematic GPS, static GPS offsets, seafloor geodesy and near-field and far-field tsunami data into a massively parallel Monte Carlo simulation, we construct an ensemble of samples of the posterior probability density function describing the evolution of fault rupture. We find that most of the slip is concentrated in a depth range of 10–20 km from the trench, and that slip decreases towards the trench with significant displacements at the toe of wedge occurring in just a small region. Estimates of static stress drop and rupture velocity are ambiguous. Due to the spatial compactness of the fault rupture, the duration of the entire rupture was less than approximately 150 s