Measurements of FEL dynamics

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Electro-optic techniques for longitudinal electron bunch diagnostics

Electro-optic techniques are becoming increasingly important in ultrafast electron bunch longitudinal diagnostics and have been successfully implemented at various accelerator laboratories. The longitudinal bunch shape is directly obtained from a single-shot, non-intrusive measurement of the temporal electric field profile of the bunch. Further- more, the same electro-optic techniques can be used to measure the temporal profile of terahertz / far-infrared opti- cal pulses generated by a CTR screen, at a bending magnet (CSR), or by an FEL. This contribution summarizes the re- sults obtained at FELIX and FLASH

Longtitudinal electron beam diagnostics via upconversion of THz to visible radiation

Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch (THz radiation) to the visible spectral range, where a variety of standard diagnostic tools are available. Standard techniques to characterise femtosecond optical laser pulses (auto- and cross-correlators) have led to the schemes that can measure electron bunch profiles with femtosecond resolution. These techniques require, however, well synchronized femtosecond laser pulses, in order to obtain the desired temporal resolution. Currently, we are exploring other electro-optic variants which require less advanced laser systems and will be more amenable to beam based longitudinal feedback applications. The first results of one such new scheme will be presented in this paper

Single shot longitudinal bunch profile measurements by temporally resolved electro-optical detection

For the high gain operation of a SASE FEL, extremely short electron bunches are essential to generate sufficiently high peak currents. At the superconducting linac of FLASH at DESY, we have installed an electro- optic measurement system to probe the time structure of the electric field of single ~100 fs electron bunches. In this technique, the field induced birefringence in an electro-optic crystal is encoded on a chirped picosecond laser pulse. The longitudinal electric field profile of the electron bunch is then obtained from the encoded optical pulse by a single shot cross correlation with a 35 fs laser pulse using a second harmonic crystal (temporal decoding). An electro-optical signal exhibiting a feature with 118 fs FWHM was observed, and this is close to the limit of resolution due to the material properties of the particular electro-optic crystal used. The measured electro-optic signals are compared to bunch shapes simultaneously measured with a transverse deflecting cavity

Benchmarking of electro-optic monitors for femtosecond electron bunches

The longitudinal profiles of ultrashort relativistic electron bunches at the soft x-ray free-electron laser FLASH have been investigated using two single-shot detection schemes: an electro-optic (EO) detector measuring the Coulomb field of the bunch and a radio-frequency structure transforming the charge distribution into a transverse streak. A comparison permits an absolute calibration of the EO technique. EO signals as short as 60 fs (rms) have been observed, which is a new record in the EO detection of single electron bunches and close to the limit given by the EO material properties

Single-shot longitudinal bunch profile measurements at FLASH using electro-optic detection:experiment, simulation, and validation

At the superconducting linac of FLASH at DESY, we have installed an electro-optic (EO) experiment for single- shot, non-destructive measurements of the longitudinal electric charge distribution of individual electron bunches. The time profile of the electric bunch field is electro- optically encoded onto a chirped titanium-sapphire laser pulse. In the decoding step, the profile is retrieved either from a cross-correlation of the encoded pulse with a 30 fs laser pulse, obtained from the same laser (electro- optic temporal decoding, EOTD), or from the spectral intensity of the transmitted probe pulse (electro-optic spectral decoding, EOSD). At FLASH, the longitudinally compressed electron bunches have been measured during FEL operation with a resolution of better than 50 fs. The electro-optic process in gallium phosphide was numerically simulated using as input data the bunch shapes determined with a transverse-deflecting RF structure. In this contribution, we present electro-optically measured bunch profiles and compare them with the simulation

966-45 QT Dispersion in Essential Hypertension

Increased QT dispersion (QTd) reflects regional variation in ventricular repolarisation, and has been shown in heart failure and hypertrophic cardiomyopathy to relate to an increased incidence of sudden death. As essential hypertensives (EH) are also at increased risk of sudden death we aimed to determine whether increased QTd is found in those EH who are known to be at the highest risk of sudden death. In 50 EH we measured QTd (maximum corrected QT interval minus minimum corrected QT interval), echocardiographic left ventricular mass index (LVMI) (n=46 as 4 patients non-echogenic), office systolic and diastolic blood pressure (SSP, DSP), and 24 hour ambulatory systolic and diastolic blood pressure (24 SSP, 24 DSP) (n=40). Univariate analysis demonstrated no relationship between QTd and age, sex, height, weight, 24 SSP or 24 DBP. Significant relationships existed between QTd and LVMI (R2=0.25, P<0.001), SSP (R2=0.16, P<0.01), DSP (R2=0.08, P<0.05). Multiple linear regression analysis revealed the only relationships to QTd were LVMI (p<0.01) and SSP (p<0.05). Excluding 4 patients with electro-cardiographic left ventricular hypertrophy (ECG-LVH) from the analysis a significant relationship between QTd and LVMI (R2=0.13, P<0.05) and SSP (R2=0.10, P<0.05) persists. These demonstrate that increased QTd is found in EH with the highest risk of sudden death (greatest SSP and LVMI). This relationship persists in the absence of ECG-LVH. Further study of QTd, as a predictor of sudden death in EH is warranted

Developing a community-based intervention to improve quality of life in people with colorectal cancer: a complex intervention development study

Objectives: To develop and pilot a theory and evidence-based intervention to improve quality of life (QoL) in people with colorectal cancer. Design: A complex intervention development study. Setting: North East Scotland and Glasgow. Participants: Semistructured interviews with people with colorectal cancer (n=28), cancer specialists (n=16) and primary care health professionals (n=14) and pilot testing with patients (n=12). Interventions: A single, 1 h nurse home visit 6–12 weeks after diagnosis, and telephone follow-up 1 week later (with a view to ongoing follow-up in future). Primary and secondary outcome measures: Qualitative assessment of intervention feasibility and acceptability. Results: Modifiable predictors of QoL identified previously were symptoms (fatigue, pain, diarrhoea, shortness of breath, insomnia, anorexia/cachexia, poor psychological well-being, sexual problems) and impaired activities. To modify these symptoms and activities, an intervention based on Control Theory was developed to help participants identify personally important symptoms and activities; set appropriate goals; use action planning to progress towards goals; self-monitor progress and identify (and tackle) barriers limiting progress. Interview responses were generally favourable and included recommendations about timing and style of delivery that were incorporated into the intervention. The pilot study demonstrated the feasibility of intervention delivery. Conclusions: Through multidisciplinary collaboration, a theory-based, acceptable and feasible intervention to improve QoL in colorectal cancer patients was developed, and can now be evaluated

Patents and Industrialisation. An Historical Overview of the British Case, 1624-1907

A Report to the Strategic Advisory Board on Intellectual Property Policy (SABIP), U

Xanthine oxidase inhibition and white matter hyperintensity progression following ischaemic stroke and transient ischaemic attack (XILO-FIST): a multicentre, double-blinded, randomised, placebo-controlled trial

Acknowledgments This work was supported by the Stroke Association and British Heart Foundation [grant number TSA BHF 2013/01]. The work of Dr David Dickie and Dr Terry Quinn is funded by the Stroke Association. We would like to thank Christine McAlpine, Ruth Graham, Glasgow Royal Infirmary, UK; Lauren Pearce, Royal United Hospital, UK; Caroline Fornolles, Louise Tate, Frances Justin, Luton and Dunstable University Hospital, UK; Dean Waugh, Leeds Teaching Hospitals NHS Trust, UK; Donal Concannon, Altnagelvin Hospital, UK; Sharon Tysoe, Nina Francia, Nisha Menon, Raji Prabakaran, Southend University Hospital, UK; Amy Ashton, Caroline Watchurst, Marilena Marinescu, Sabaa Obarey, Scheherazade Feerick, University College London NHS Foundation Trust, UK; and Janice Irvine, Sandra Williams, and German Guzman Gutierrez, Aberdeen Royal Infirmary, UK; Caroline Fox and Joanne Topliffe, Broomfield Hospital, Essex, UK.Peer reviewedPublisher PD