Laser Wire Scanner Compton Scattering Techniques for the Measurement of the Transverse Beam Size of Particle Beams at Future Linear Colliders

This archive summarizes a working paper and conference proceedings related to laser wire scanner development for the Future Linear Collider (FLC) in the years 2001 to 2006. In particular the design, setup and data taking for the laser wire experiments at PETRA II and CT2 are described. The material is focused on the activities undertaken by Royal Holloway University of London (RHUL).Comment: 61 page

Optimisation and characterisation of durable microelectrodes for electroanalysis in molten salt

This work presents microfabricated microelectrodes, capable of quantitative analysis in molten salt (MS). MSs are an electrolytic medium of growing interest, especially in the area of nuclear reprocessing. However, designing sensors for a MS-based nuclear reprocessing system is a challenge, owing to the usually corrosive nature and high operating temperatures (typically 450 - 500◦C) of MS. Microelectrodes are well placed as sensors, with numerous advantages over macro-scale electrodes. As a consequence, there have been previous attempts to utilise microelectrodes inMS. However, these have not been successful and all have suffered disadvantages inherent in traditional microelectrode manufacturing. The microelectrodes presented in this work were produced using standard microfabrication techniques and characterised in MS. An analysis of failure mechanisms guided a systematic study of material combinations. This resulted in a sensor, which is capable of delivering quantifiable electrochemistry in MS. However, the lifetime and yield of the sensor were determined to only be 46% and 1.4 hours respectively. Further investigation of the microelectrode failure mechanisms guided several layout changes to the microelectrode design. By reducing critical area, where defects or pinholes could form, these resulted in improvements in performance. This increased the yield to 65%, while the average lifetime increased up to 45 hours. Test structures were designed to investigate the causes of the continued microelectrode failures and identified shorting between the electrode metal and silicon substrate. This suggests the existence of defects in the underlying insulator are the cause of the 35% of microelectrodes which never functioned. Separate test structures suggested the lifetimes of the microelectrodes could also be improved by removing the need for a metal adhesion layer. Tantalum has been suggested as a replacement electrode metal and a proof of concept study demonstrated the feasibility of employing thin film tantalum as an electrode metal in LKE. Using this technology as a platform, several proof-of-concept microelectrode designs are also presented: liquid microelectrodes, microelectrode arrays, and a nanoelectrode. These are targeted at specific sensing applications, and provide an expanded spectrum of measurements in MS

Superconductivity in high energy particle accelerators

The basics of superconductivity are outlined with special emphasis on the features which are relevant for the application in magnets and radio frequency cavities for high energy particle accelerators. The special properties of superconducting accelerator magnets are described in detail: design principles, magnetic field calculations, magnetic forces, quench performance, persistent magnetization currents and eddy currents. The design principles and basic properties of superconducting cavities are explained as well as the observed performance limitations and the countermeasures. The ongoing research efforts towards maximum accelerating fields are addressed and the coupling of radio frequency power to the particle beam is treated. (orig.)Available from TIB Hannover: RA 2999(02-116) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman