| 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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| 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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| 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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| WEPOMS011 | Single Bunch Instability Studies with a New Impedance Database for Diamond-II | 2257 |
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| We present an updated impedance database for the Diamond-II storage ring, along with an analysis of single bunch instabilities and thresholds based on particle tracking simulations using Elegant. Various cases with different chromaticity, insertion device parameters and harmonic cavity settings are studied, and the effects on the microwave instability, bunch lengthening and phase shifts are simulated and compared with analytic formulae. Preliminary results show that the single-bunch instability thresholds are above requirements for a uniform fill, and with inclusion of a harmonic cavity the longitudinal and transverse instability thresholds can also satisfy requirements for a hybrid fill. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS011 | |
| About • | Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022 | |
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| THPOPT016 | Commissioning Simulations for the DIAMOND-II Upgrade | 2598 |
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| The Diamond-II storage ring, compared to Diamond, improves the natural beam emittance from 2.7 nm to 160 pm and the beam energy from 3 to 3.5 GeV. The number of straight sections is also doubled from 24 to 48 thanks to the modified hybrid six-bend-achromat lattice. To reduce the impact on the existing science program, the dark time period must be minimised. To assist in this aim, storage ring commissioning simulations have been carried out to predict and resolve possible issues. These studies include beam commissioning starting from on-axis first-turn beam threading up to beam based alignment and full linear optics correction with stored beam. The linear optics corrections with insertion devices are also included. The machine characterisations at different stages are compared. Considerations on realistic chamber limitations, error definitions and some commissioning strategies are also discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT016 | |
| About • | Received ※ 19 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022 | |
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| THPOPT048 | Impact of IDs on the Diamond Storage Ring and Application to Diamond-II | 2705 |
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| When investigating the effect of insertion devices (IDs) on storage ring operations, it is not possible to simulate all of the large number of gap, phase and field settings that are available. This can be of particular concern for transient effects in IDs that are moved frequently, or APPLE-II devices which may use many different polarisation states. We therefore present measurements of the impact of selected IDs on various parameters in the current Diamond storage ring including orbit distortion, tunes, chromaticity and emittance, and assess the expected impact when applied to the Diamond-II lattice. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT048 | |
| About • | Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 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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