| Paper | Title | Page |
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| MOPAB132 | Beam Size Measurement Using High Aspect Ratio LIGA Apertures in an X-Ray Pinhole Camera | 445 |
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| For optimal brilliance third generation light sources operate at a low emittance and low coupling. Commonly, transverse beam profile measurements are provided by direct imaging of the electron beam using X-ray pinhole cameras. From these beam size measurements and given knowledge of the lattice parameters the emittance, coupling and energy spread are calculated. Ideally, the pinhole aperture should be formed in an infinitely thin screen. However, due to the penetration of X-rays in the keV spectral range, stacked tungsten blades are often used to form the pinhole aperture. In this arrangement the absolute size of the pinhole aperture is unknown and cannot be directly measured, which affects the spatial resolution of the imaging system. Here we investigate the use of X-ray Lithography, Electroplating and Moulding (commonly known as LIGA) to fabricate high aspect ratio pinhole apertures in a gold screen of approximately 1 mm thickness. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB132 | |
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| MOPAB133 | Optimisation of Electrical and Instrumentation Design for the Diamond Light Source DDBA Upgrade | 448 |
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| In planning the upgrade of one cell of the Diamond Storage Ring, the DDBA upgrade, it was evident that the electrical installation and commissioning would contribute a significant component of the overall installation time. Given the pressures to minimise the shutdown length, the electrical and instrumentation design was optimised for time effective installation and commissioning. This paper outlines the electrical and instrumentation design for DDBA; explores the installation time determining issues and how these were addressed; and reports on the lessons learnt from the actual installation and commissioning process. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB133 | |
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| TUPIK113 | Performance of the Fast Orbit Feedback System with the Double-Double Bend Achromat Installed in Diamond Light Source | 1989 |
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| At Diamond Light Source, the Double-Double Bend Achromat (DDBA) lattice upgrade involved the conversion of one cell of the storage ring from a double bend achromat (DBA) structure to a double-DBA (DDBA). The new cell includes corrector magnets that are different in design to the DBA corrector magnets. The DDBA vacuum chamber cross section is also different from the DBA cells and includes both stainless steel and copper sections over which corrector magnets are fitted. The performance of the Fast Orbit Feedback (FOFB) used for electron beam stabilisation with the DDBA cell installed is presented in this paper. Firstly the different corrector magnet dynamic responses are characterised and secondly the closed loop performance of the FOFB is measured and analysed for the upgraded lattice. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK113 | |
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| TUPIK114 | First Experiences with the Longitudinal Feedback System at Diamond Light Source | 1992 |
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| In order to avoid longitudinal multibunch instabilities potentially caused by the addition of normal conducting RF cavities into the Diamond storage ring, a longitudinal feedback was installed. The main components are newly developed feedback electronics, in-house built modulator and amplifier, and a low Q kicker cavity. This paper describes the performance of the cavity as well as the full longitudinal feedback system as it is installed on the machine and tested before the installation of the normal conducting RF cavities. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK114 | |
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| WEPAB095 | Electron Beam Commissioning of the DDBA Modification to the Diamond Storage Ring | 2800 |
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The Diamond storage ring has been modified by replacing one of the existing double bend achromat (DBA) cells with a double-DBA (DDBA) cell*. This change represents the largest modification to the storage ring since it was first commissioned in 2006, and was installed and fully commissioned during a single 8 week shutdown in autumn 2016. In view of this tight schedule, the planned commissioning steps and all high-level software needed to be developed and thoroughly tested in advance. Electron beam commissioning occupied the final 2 weeks of the shutdown, during which the injected electrons were captured and accumulated, the correct linear lattice was established, the nonlinear beam dynamics were studied, IDs were closed and the target 300 mA was achieved. This paper presents an overview of these activities.
* R.P. Walker et al., 'The Double-Double Bend Achromat (DDBA) Lattice Modification for the Diamond Storage Ring', Proc. IPAC 2014, MOPRO103, (2014) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB095 | |
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| WEPAB096 | Diamond Light Source: A 10-year View of the Past and Vision of the Future | 2804 |
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| Diamond Light Source has been in regular operation for users for 10 years and so it is an appropriate moment to review the successes and challenges of the past, and also consider the vision for the next 10 years. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB096 | |
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| WEPIK102 | Measurement of RF Resonances and Measured Impact on Transverse Multibunch Instabilities from In-vacuum Insertions Devices | 3188 |
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| Diamond Light Source has currently 15 in-vacuum insertion devices (ID) installed, mostly built in-house. Their measured impact on multi-bunch mode damping as a result of varying magnet gap was shown before, now we augment these with measurements of broadband frequency spectra with stored beam obtained using an antenna placed in the ID vacuum. Finally, we present off-line measurements of resonances in the ID vessel acquired using a vector network analyser and two antennae installed in-vacuum. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK102 | |
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| THPVA028 | Multi-Bunch Instabilities Measurement and Analysis at the Diamond Light Source | 4485 |
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| The characterisation of the multi-bunch dynamics at the Diamond light source is performed with an advanced TMBF system that is capable of operating fast grow damp experiments thus allowing the exploration of many machine conditions. We report here the latest results of the measurement campaign, the implication on the machine impedance model and some of the intricacies of the analysis and interpretation of the experimental data. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA028 | |
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| THPVA029 | Study of Single Bunch Instabilities with Transverse Feedback at Diamond | 4489 |
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| Single bunch instability studies have been carried out at Diamond with and without the transverse multi-bunch feedback (TMBF) system. Single bunch instability thresholds were measured for zero, positive and negative chromaticity values by increasing the current till the instability onset. The bunch-by-bunch feedback system was then used to suppress the motion of the bunch centroid and the new thresholds were measured in all chromaticity regimes. The feedback loop phase of the TMBF was changed from resistive to reactive as well as intermediate to find the optimal feedback settings that maximize the single bunch instability thresholds. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA029 | |
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