| Paper | Title | Page |
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| MOPRO103 | The Double-double Bend Achromat (DDBA) Lattice Modification for the Diamond Storage Ring | 331 |
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The concept of converting individual cells of the Diamond Double Bend Achromat (DBA) lattice into a modified 4-bend achromat with a new straight section for insertion devices (IDs) in the middle of the arc, grew out of earlier studies of low emittance MBA lattices*, and was motivated by the need for additional ID straight sections, since all of the 22 ID straight sections in the Diamond storage ring are either occupied or have been allocated to future beamlines. Such a modification effectively replaces each DBA cell with two new DBA cells, hence the term Double-DBA or DDBA has come to be used for the project. Since the tangent point for bending magnet beamlines lies close to the start of the second dipole in the original DBA, this allows unused exit ports and spaces on the experimental hall which are available for future bending magnet beamlines to be used for higher performance ID beamlines. In this report we present an overview of the status of the project, the various accelerator physics and engineering studies that have been carried out, and plans for the implementation of one or two DDBA cells in Diamond.
* R. Bartolini, IPAC'13, p. 237 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO103 | |
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| TUPRI081 | Feed-forward and Feedback Schemes applied to the Diamond Light Source Storage Ring | 1757 |
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| Since initial operation for users in Jan 2007, Diamond Light Source has developed to support a suite of 22 experimental stations. These stations have resulted in the installation of 24 undulators and two superconducting wigglers in the storage ring. To preserve optics, tune and coupling with the operation of these devices has necessitated the implementation of a number of feed-forward and feedback schemes. The implementation and operation of these correction schemes will be described. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI081 | |
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| TUPRI082 | Active Optics Stabilisation Measures at the Diamond Storage Ring | 1760 |
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| The Diamond storage ring is currently operated with 26 insertion devices (IDs), including 14 in-vacuum IDs, 7 APPLE-II type helical undulators and 2 superconducting wigglers. Differences in the design, construction and operation of these devices, combined with different Twiss parameters at the source point, mean each has a different impact on tune stability and beta-beat. In turn, these parameters affect the on and off-momentum dynamic aperture and ultimately impact on the injection efficiency and lifetime. Another source of optics variation arises from the coherent tune shift with current, which when injecting from zero current causes the tune to span the available good-tune region. In this paper we discuss the difficulties of operating the Diamond storage ring in top-up mode with these effects, and present the various measures taken to stabilise the storage ring optics. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI082 | |
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| TUPRI083 | A Fast Optics Correction for the Diamond Storage Ring | 1763 |
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Since March 2013, the Diamond storage ring has been operated with a target vertical emittance of 8 pm.rad. This condition is achieved by first applying a LOCO* optics correction with IDs set to their typical gaps, then offsetting the skew quadrupole magnets in order to increase the vertical emittance again to the desired value. Whilst a feedback application** is able to stabilise the vertical emittance during ID gap and phase changes in the short to medium term, regular applications of LOCO are still required to maintain good coupling control in the longer term. In this paper we describe measures taken to speed up the optics correction procedure, including a fast orbit response matrix measurement, a reduction of the number of magnets used to measure the data, and a distribution of the LOCO calculations to run in parallel.
* J. Safranek, Nucl. Inst. Meth. A, 338, (1997) ** I.P.S. Martin, et al., IPAC 2013, MOPEA071, www. JACoW.org |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI083 | |
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| THPME183 | Longitudinal Beam Profile Measurements of the Microbunching Instability | 3706 |
| SUSPSNE075 | use link to see paper's listing under its alternate paper code | |
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| The microbunching instability is a phenomenon characterized by the onset of radiation bursts above a threshold bunch current. These bursts consist of coherent emissions with wavelengths comparable to the bunch length and shorter. The instability has recently been observed at Diamond Light Source, a 3rd generation synchrotron. The operating conditions for triggering the instability at Diamond Light Source are well known, however measuring the spectral content of the resulting emissions is a more challenging investigation. A Michelson interferometer has been installed with the aim of recording the coherent spectrum from the bunches, using ultra-fast response Schottky Barrier Diode detectors. The longitudinal profile of the bunches can be estimated with subsequent analysis. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME183 | |
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| THPME188 | Using Principal Component Analysis to Find Correlations and Patterns at Diamond Light Source | 3719 |
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| Principal component analysis is a powerful data analysis tool, capable of reducing large complex data sets containing many variables. Examination of the principal components set allows the user to spot underlying trends and patterns that might otherwise be masked in a very large volume of data, or hidden in noise. Diamond Light Source archives many gigabytes of machine data every day, far more than any one human could effectively search through for correlations. Presented in this paper are some of the results from running principal component analysis on years of archived data in order to find underlying correlations that may otherwise have gone unnoticed. The advantages and limitations of the technique are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME188 | |
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