| Paper | Title | Page |
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| MOPOTK037 | Impact of Insertion Devices on Diamond-II Lattice | 539 |
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Funding: DLS ltd The DIAMOND-II lattice is based on the ESRF-EBS cell, with the centre dipole replaced by a (chromatic) mid-straight, and a -I transformer, higher order achromat (HOA) & dispersion bumps to control the nonlinear dynamics. The majority of insertion devices currently on operation in Diamond will be either retained or upgraded as part of the Diamond-II program, and the new mid straights allow the total number of ID beamlines to be increased from 28 to 36.Therefore, it is important to investigate how IDs will affect the emittance, energy spread and linear and nonlinear beam dynamics. The kickmap approach has been used to model all IDs, including APPLE-II and APPLE-II Knot with active shim wires. In this paper, the outcome of these investigations will be presented and discussed. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK037 | |
| About • | Received ※ 04 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 07 July 2022 | |
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| TUPOMS031 | Fill Pattern for Reducing Transient Beam Loading and Ion-Trapping in the Diamond-II Storage Ring | 1483 |
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| The Diamond-II upgrade will replace the existing Diamond storage ring with a multibend achromat lattice providing higher brightness to the users by reducing the emittance and increasing the beam energy. The new storage ring will require a harmonic cavity that lengthens the bunches to increase the Touschek lifetime as well as mitigate instabilities and suppress the emittance blow up from intrabeam scattering. It is expected that the ring will have to operate with gaps in the fill pattern for ion-clearing, but that will lead to transient beam loading resulting in reduced bunch lengthening. The length and occurrence of the gaps therefore have to be determined as a trade-off between the requirements for transient beam loading and ion-trapping. This paper presents simulations of both effects for the Diamond-II storage ring to find an optimal fill pattern. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS031 | |
| About • | Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022 | |
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| TUPOMS033 | Diamond-II Storage Ring Developments and Performance Studies | 1491 |
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The Diamond-II project includes a replacement of the existing double-bend achromat storage ring with a modified hybrid 6-bend achromat, doubling the number of straight sections and increasing the photon beam brightness by up to two orders of magnitude*. The design and performance characterisation of the new storage ring has continued to progress, including a switch to an aperture-sharing injection scheme, freezing the magnet layout, studying the impact of IDs, developing a commissioning procedure and investigating collective effects. In this paper we present an overview of these studies, including final performance estimates.
*Diamond-II Technical Design Report, Diamond Light Source Ltd. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS033 | |
| About • | Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 27 June 2022 | |
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| TUPOMS035 | Emittance Feedback for the Diamond-II Storage Ring Using Resonant Excitation | 1498 |
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| In the Diamond Light Source storage ring, the vertical emittance is kept at 8 pm rad during operation to maintain the source brightness for the users. This is achieved by a feedback which modifies the skew quadrupole strengths, but has disadvantages such as the introduction of betatron coupling and vertical dispersion. For the proposed Diamond-II upgrade, the storage ring will have a much smaller horizontal emittance, meaning a significantly larger coupling would be required to reach the target vertical emittance, negatively affecting the off-axis injection process. To solve this problem, a feedback using the transverse multibunch feedback striplines to drive the beam at a synchrotron sideband is planned. By driving the beam resonantly in this way, the emittance can be increased without modification of the optics. This paper describes simulations of the effects of linear and non-linear optics on the excitation as well as the impact of the machine impedance for the Diamond-II storage ring. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS035 | |
| About • | Received ※ 19 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022 | |
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| WEPOMS010 | Studies of Transverse Coupled-Bunch Instabilities from Resistive-Wall and Cavity Higher Order Modes for Diamond-II | 2253 |
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| The transverse coupled-bunch instabilities from resistive-wall impedance and main cavity higher order modes (HOMs) are studied for the Diamond-II storage ring. The growth rates of all the coupled-bunch modes are calculated using both the results from tracking simulations and analytic formula, which show a good consistency. The instability threshold from the resistive-wall impedance is estimated and verified by simulation. The impact of the main cavity HOMs is studied in a similar way, and the results show instabilities from HOMs are much smaller than that from resistive-wall impedance. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS010 | |
| About • | Received ※ 06 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 05 July 2022 | |
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| THPOPT017 | Orbit Stability Studies for the Diamond-II Storage Ring | 2602 |
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| The photon-beam positional stability relative to the beam size is a key performance parameter for storage ring light sources. The natural emittance of the Diamond-II ring will be lowered by a factor 16.7 compared to the existing ring, so the absolute stability requirement for the electron beam must reduce accordingly. In addition, advances in detector speed and resolution mean the tolerances are tighter compared to previous generations of storage rings, with a target of 3 % of beam size up to 1 kHz having been adopted for Diamond-II. In this paper we present studies of how the anticipated ground vibrations, girder motion and power supply ripple will affect the electron beam stability as a function of frequency. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT017 | |
| About • | Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 06 July 2022 | |
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| THPOPT049 | Beam Dynamics Studies for the Diamond-II Injector | 2708 |
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The replacement, low-emittance booster for the Diamond-II project will have a racetrack structure of 36 units cells constructed from alternating focussing and defocussing combined-function dipoles*. In this paper we report on how the design and performance characterisation of the booster has recently developed; this includes an increase in the injection energy from 100 to 150 MeV, a modified circumference to match to the storage ring RF frequency, and a new nominal tune-point to improve the performance and enable emittance exchange. The influence of the vacuum chamber impedance and intra-beam scattering on the electron bunch parameters during the ramp are presented, along with the necessary changes to the transfer line layouts.
*I.P.S. Martin, et al. "Progress with the Booster Design for the Diamond-II Upgrade", in Proc. IPAC’21, paper ID MOPAB071, Campinas, Brazil, May 2021 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT049 | |
| About • | Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022 | |
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