| Paper | Title | Page |
|---|---|---|
| MOPEA066 | Investigation and Test of the Possibility of Reducing the Emittance of the Diamond Storage Ring | 234 |
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| Theoretical and experimental studies have been carried out at the Diamond Light Source to assess the possibility of reducing the emittance of the existing storage ring by means of a change to the optics. The optics solutions obtained so far using a Multi Objective Genetic Algorithm (MOGA) increase the dispersion and the horizontal beta function in the straight section. While the emittance can be reduced to 2.1 nm this optics is limited by the operation of high field superconducting wiggler devices. In this report we present details of the new optics and present results of practical tests. We also compare the theoretical emittance growth due to a wiggler in a dispersive region with test results. | ||
| MOPEA067 | Ultra-low Emittance Upgrade Options for Third Generation Light Sources | 237 |
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| The increasing efforts in the synchrotron light sources community toward the design of a diffraction limited source at multi-keV photon energy have eventually stimulated the existing facilities to investigate possible upgrade paths to higher photon brightness and lower emittances to maintain their competitiveness within the users’ community. We present a possible option for upgrading 3rd generation light sources based on a rebiuld of the arcs with MBA cells, using diamond as an example. Emphasis is given to the AP desing issues with a view to minimal changes to the machine layout, contained cost and minimal downtime | ||
| MOPEA068 | Novel Lattice Upgrade Studies for Diamond Light Source | 240 |
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| Many synchrotron radiation facilities are studying lattice upgrades in order to lower the natural emittance and hence increase the radiation brightness. At Diamond we are pursuing a novel alternative, not targeting the minimum possible emittance but instead introducing additional insertion device (ID) straights and hence increasing the capacity of the facility, while still possibly achieving a more limited reduction in emittance. The new scheme involves converting some of the DBA lattice cells into a double-DBA or DDBA, with a new ID straight between the two achromats. This then allows existing or future bending magnet ports (which in Diamond are taken from near the entrance to the second dipole of the DBA lattice) to be served by a much more powerful insertion device. We present here the design concept and preliminary lattice design, and discuss the challenging magnet, vacuum and engineering issues. | ||
| MOPEA069 | Tuning of the Injector System to Match Possible Lattice Upgrades at Diamond Light Source | 243 |
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| Studies of novel lattice upgrades for Diamond Light Source to achieve an increase in the number of insertion devices and/or a lower natural emittance are underway (as reported elsewhere at this conference). Such upgrades if carried out progressively would result in successive reductions in storage ring circumference. To maintain synchronous injection then requires the injector system to operate at various frequencies to match these changes. This paper describes the tests carried out with beam, to prove that the injector system of Linac and full energy Booster can be tuned over an extended frequency range. | ||
| MOPEA070 | Operating the Diamond Light Source in Low Alpha Mode for Users | 246 |
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| Since its first introduction in April 2009, the low alpha operational mode has been continually refined in order to best meet the needs of the user community. Initially the optics were used only to generate short x-ray pulses, for which a stable, low emittance, single bunch was requested, with the emphasis placed on increased bunch charge over shortest absolute pulse duration. More recently, the optics have been adapted to enhance the CSR gain in the THz region of the electromagnetic spectrum. In this paper we summarise the work carried out in order to meet these two demands. | ||
| MOPEA071 | Operating the Diamond Storage Ring with Reduced Vertical Emittance | 249 |
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| In a synchrotron radiation light source, a reduction in vertical emittance can potentially increase the source brightness, reduce the spot size for microfocus beam lines or increase the vertical transverse coherence of the photon beam. With this aim, the target vertical emittance for the Diamond storage ring has been recently reduced from 27pm.rad to 8pm.rad (0.3% coupling). In this paper we discuss the main impacts of this reduction, along with the steps that have been taken to stabilise the coupling at the new value. | ||
| MOPWA056 | Spectra of Coherent Smith-Purcell Radiation Observed from Short Electron Bunches: Numerical and Experimental Studies | 801 |
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Funding: This work performed [in part] under DOE Contract DE-AC02-7600515 There is a significant interest in the development of compact particle accelerators within research areas including X-ray and THz (T-ray) sources of radiation, particle physics and medical sciences. To support the progress in these areas, non-invasive, electron beam diagnostics that are capable of measuring a single femtosecond electron bunch are required. At the current stage such beam diagnostics for femtosecond-long electron bunches are still not available. The goal of the work presented is to understand the spectral characteristics of coherent Smith-Purcell radiation to enable its quick and reliable interpretation including the longitudinal profile reconstruction of electron bunches. The research presented comprises results from numerical modelling and experimental studies. Using the numerical data, we discuss the radiated spectra dependence on the electron bunch profile and analyse the results. We also discuss the experimental data and compare it with theoretical predictions. |
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| TUPEA058 | The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation | 1265 |
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| The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven. | ||
| TUPWA052 | Loss Factor and Impedance Analysis for the Diamond Storage Ring | 1826 |
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| Diamond Light Source is investigating the possibility of increasing the storage ring operating current above the nominal 300 mA. A campaign of measurements and simulations has been carried out in order to understand the extent of the parasitic energy loss and characterise the most important items which build up the machine impedance. In this paper we report on the most recent measurements of the longitudinal loss factor and the present status of the impedance database with an initial comparison between the two. | ||
| TUPWO057 | Active Shimming of Dynamic Multipoles of an APPLE II Undulator in the Diamond Storage Ring | 1997 |
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| Diamond plans to operate a 5 m, long period length, APPLE undulator in a long insertion straight section. Theoretical investigations showed a severe impact on machine dynamics especially when the device is operated in vertical polarization mode. The use of local optics corrections and/or lowering of beta functions were initially investigated as possible solutions but with limited success. Active shimming of dynamic multipoles, following the approach at BESSY-II, proved more effective. The optimum shiming has been devised using kick map approach. In this paper we review the theoretical analysis, the commissioning of the active shims and the undulator, and the net effect of the undulator after compensation. | ||
| WEPWA006 | Beam Heat Load Measurements with COLDDIAG at the Diamond Light Source | 2135 |
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| Understanding the heat load from an electron beam is still an open issue for the cryogenic design of superconducting insertion devices. COLDDIAG, a cold vacuum chamber for diagnostics was designed and built specially for this purpose. With the equipped instrumentation, which covers temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers it is possible to measure the beam heat load, total pressure, and gas content as well as the net flux and energy of particles hitting the chamber walls. Following a failure after its first installation in November 2011, COLDDIAG was subsequently reinstalled in the Diamond storage ring in August 2012. We report on the preliminary results that have been obtained since then. | ||
| WEPWA065 | A Non-linear Injection Kicker for Diamond Light Source | 2268 |
|
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| Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined. | ||
| WEPME054 | Girder Alignment in the Diamond Storage Ring | 3052 |
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| A model of the Diamond Storage Ring describing the misalignment of its 74 girders in terms of displacements and rotations is used to predict the orbit distortions and corrector magnet strengths needed for a zero orbit. Using the data from a survey we compare the effect of a pure magnet misalignment with the natural orbit of the machine. A test with a displaced girder meant to produce a reduction in corrector strength is introduced. Comparison with data obtained from the actual move of the girder is presented and discussed. | ||
| WEPME055 | Investigation of Source Point Instabilities in Dipole Magnet Based Beamlines | 3055 |
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| At Diamond the source point in the second dipole of the Double Bend Achromats can vary due the lack of adjacent BPMs constraining angle and position of the electron beam at the dipole. We have implemented a code based on our AT model to predict the effects of a corrector strength change and compared our predictions to data both from a beamline and from our pinhole cameras. We discuss the possibility of interfacing the code to a ray tracing routine in order to infer beam spot changes in the downstream beamline and suggest a procedure to restore the original source point. | ||
| MOPEA068 | Novel Lattice Upgrade Studies for Diamond Light Source | 240 |
|
||
| Many synchrotron radiation facilities are studying lattice upgrades in order to lower the natural emittance and hence increase the radiation brightness. At Diamond we are pursuing a novel alternative, not targeting the minimum possible emittance but instead introducing additional insertion device (ID) straights and hence increasing the capacity of the facility, while still possibly achieving a more limited reduction in emittance. The new scheme involves converting some of the DBA lattice cells into a double-DBA or DDBA, with a new ID straight between the two achromats. This then allows existing or future bending magnet ports (which in Diamond are taken from near the entrance to the second dipole of the DBA lattice) to be served by a much more powerful insertion device. We present here the design concept and preliminary lattice design, and discuss the challenging magnet, vacuum and engineering issues. | ||
| MOPEA069 | Tuning of the Injector System to Match Possible Lattice Upgrades at Diamond Light Source | 243 |
|
||
| Studies of novel lattice upgrades for Diamond Light Source to achieve an increase in the number of insertion devices and/or a lower natural emittance are underway (as reported elsewhere at this conference). Such upgrades if carried out progressively would result in successive reductions in storage ring circumference. To maintain synchronous injection then requires the injector system to operate at various frequencies to match these changes. This paper describes the tests carried out with beam, to prove that the injector system of Linac and full energy Booster can be tuned over an extended frequency range. | ||
| MOPEA070 | Operating the Diamond Light Source in Low Alpha Mode for Users | 246 |
|
||
| Since its first introduction in April 2009, the low alpha operational mode has been continually refined in order to best meet the needs of the user community. Initially the optics were used only to generate short x-ray pulses, for which a stable, low emittance, single bunch was requested, with the emphasis placed on increased bunch charge over shortest absolute pulse duration. More recently, the optics have been adapted to enhance the CSR gain in the THz region of the electromagnetic spectrum. In this paper we summarise the work carried out in order to meet these two demands. | ||
| MOPEA071 | Operating the Diamond Storage Ring with Reduced Vertical Emittance | 249 |
|
||
| In a synchrotron radiation light source, a reduction in vertical emittance can potentially increase the source brightness, reduce the spot size for microfocus beam lines or increase the vertical transverse coherence of the photon beam. With this aim, the target vertical emittance for the Diamond storage ring has been recently reduced from 27pm.rad to 8pm.rad (0.3% coupling). In this paper we discuss the main impacts of this reduction, along with the steps that have been taken to stabilise the coupling at the new value. | ||
| MOPME068 | Feasibility Study of a 2nd Generation Smith-Purcell Radiation Monitor for the ESTB at SLAC | 634 |
|
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| The use of a radiative process such as the Coherent Smith-Purcell Radiation (CSPR) is a very promising non-invasive technique for the reconstruction of the time profile of relativistic electron bunches. Currently existing CSPR monitors do not have yet single-shot capability. Here we study the feasibility of using a CSPR based monitor for bunch length measurement at the End Station Test Beam (ESTB) at SLAC. The aim is to design a second-generation device with single-shot capability, and use it as a diagnostic tool at ESTB. Simulations of the spectral CSPR energy distribution and feasibility study have been performed for the optimization of the parameters and design of such a device. | ||
| TUPWO057 | Active Shimming of Dynamic Multipoles of an APPLE II Undulator in the Diamond Storage Ring | 1997 |
|
||
| Diamond plans to operate a 5 m, long period length, APPLE undulator in a long insertion straight section. Theoretical investigations showed a severe impact on machine dynamics especially when the device is operated in vertical polarization mode. The use of local optics corrections and/or lowering of beta functions were initially investigated as possible solutions but with limited success. Active shimming of dynamic multipoles, following the approach at BESSY-II, proved more effective. The optimum shiming has been devised using kick map approach. In this paper we review the theoretical analysis, the commissioning of the active shims and the undulator, and the net effect of the undulator after compensation. | ||
| WEPWA065 | A Non-linear Injection Kicker for Diamond Light Source | 2268 |
|
||
| Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined. | ||
| WEPME054 | Girder Alignment in the Diamond Storage Ring | 3052 |
|
||
| A model of the Diamond Storage Ring describing the misalignment of its 74 girders in terms of displacements and rotations is used to predict the orbit distortions and corrector magnet strengths needed for a zero orbit. Using the data from a survey we compare the effect of a pure magnet misalignment with the natural orbit of the machine. A test with a displaced girder meant to produce a reduction in corrector strength is introduced. Comparison with data obtained from the actual move of the girder is presented and discussed. | ||
| WEPME055 | Investigation of Source Point Instabilities in Dipole Magnet Based Beamlines | 3055 |
|
||
| At Diamond the source point in the second dipole of the Double Bend Achromats can vary due the lack of adjacent BPMs constraining angle and position of the electron beam at the dipole. We have implemented a code based on our AT model to predict the effects of a corrector strength change and compared our predictions to data both from a beamline and from our pinhole cameras. We discuss the possibility of interfacing the code to a ray tracing routine in order to infer beam spot changes in the downstream beamline and suggest a procedure to restore the original source point. | ||