46 research outputs found
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
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Comparative Study of Bunch Length And Arrival Time Measurements at Flash
Diagnostic devices to precisely measure the longitudinal electron beam profile and the bunch arrival time require elaborate new instrumentation techniques. At FLASH, two entirely different methods are used. The bunch profile can be determined with high precision by a transverse deflecting RF structure, but the method is disruptive and does not allow to monitor multiple bunches in a macro-pulse train. It is therefore complemented by two non-disruptive electrooptical devices, called EO and TEO. The EO setup uses a dedicated diagnostic laser synchronized to the machine RF. The longitudinal electron beam profile is encoded in the intensity profile of a chirped laser pulse and analyzed by looking at the spectral composition of the pulse. The second setup, TEO, utilizes the TiSa-based laser system used for pump-probe experiments. Here, the temporal electron shape is encoded into the spatial dimension of the laser pulse by an intersection angle between the laser and the electron beam at the EO-crystal. In this paper, we present a comparative study of bunch length and arrival time measurements performed simultaneously with all three experimental techniques
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
Polaritäten und elektrische Verbindungen der supraleitenden Magnete und Korrekturspulen im HERA-Protonenring
Far-infrared transition and diffraction radiation. II: The THz beamline at the VUV-FEL linac
Heat effects measurements in process of dynamic crash of polymer composites
In the work, the attempt to determine the influence of loading rate on temperature of the surface of the crushed composite energy absorbing elements was undertaken. The specimens made of epoxy composites reinforced with glass fabrics and carbon fabrics of the structures [(0/90)T ]n were subjected to dynamic investigations. Thermovision investigations were conducted during energy absorbing tests. A thermovision camera enables the measurement of the temperature on the whole surface of the specimen visible in the camera lens while the measurement with the use of thermocouple is only local and has great heat inertia. During the investigations, the increase of specimen temperature related to impact velocity occurs. The temperature increase is caused by friction between the particles of the crushed specimen and by friction between the specimen and the support of the strength machine. At high loading rates, the increase of temperature on the surface of the specimens was significantly greater than the softening temperature of the epoxy resin E-53
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