Publications by Riccardo Bartolini


On-line control of the nonlinear dynamics for synchrotrons

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 18 (2015) ARTN 074002

J Bengtsson, IPS Martin, JH Rowland, R Bartolini


Beam-based model of broad-band impedance of the Diamond Light Source

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 18 (2015) ARTN 064401

V Smaluk, I Martin, R Fielder, R Bartolini


Coupling impedance of an in-vacuum undulator: Measurement, simulation, and analytical estimation

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 17 (2014) ARTN 074402

V Smaluk, R Fielder, A Blednykh, G Rehm, R Bartolini


CLARA conceptual design report

JOURNAL OF INSTRUMENTATION 9 (2014) ARTN T05001

JA Clarke, D Angal-Kalinin, N Bliss, R Buckley, S Buckley, R Cash, P Corlett, L Cowie, G Cox, GP Diakun, DJ Dunning, BD Fell, A Gallagher, P Goudket, AR Goulden, DMP Holland, SP Jamison, JK Jones, AS Kalinin, W Liggins, L Ma, KB Marinov, B Martlew, PA McIntosh, JW McKenzie, KJ Middleman, BL Militsyn, AJ Moss, BD Muratori, MD Roper, R Santer, Y Saveliev, E Snedden, RJ Smith, SL Smith, M Surman, T Thakker, NR Thompson, R Valizadeh, AE Wheelhouse, PH Williams, R Bartolini, I Martin, R Barlow, A Kolano, G Burt, S Chattopadhyay, D Newton, A Wolski, RB Appleby, HL Owen, M Serluca, G Xia, S Boogert, A Lyapin, L Campbell, BWJ McNeil, VV Paramonov


Studies on LPWA-based light sources driven by a transverse gradient undulator

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 2937-2939

T Chanwattana, R Bartolini, A Seryi

Copyright © 2014 CC-BY-3.0 and by the respective authors. The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a Laser Plasma Wakefield Accelerator (LPWA) based light source driven by a transverse gradient undulator is being investigated. This report presents the accelerator physics, FEL studies and the performance expected from such a facility.


Short pulses THZ FEL for the Oxford accelerator science laboratory

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 2934-2936

T Chanwattana, R Bartolini, A Seryi, E Tsesmelis

Copyright © 2014 CC-BY-3.0 and by the respective authors. The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a short pulse THz FEL based on a conventional RF accelerator driven by a RF photocathode gun is being investigated. This report presents the concept of the facility, the accelerator physics and FEL studies and engineering integration in the University physics department.


Active optics stabilisation measures at the Diamond storage ring

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 1760-1762

IPS Martin, R Fielder, M Furseman, E Longhi, G Rehm, W Rogers, A Rose, B Singh, R Bartolini

Copyright © 2014 CC-BY-3.0 and by the respective authors. 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.


A fast optics correction for the diamond storage ring

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 1763-1765

IPS Martin, M Abbott, M Furseman, G Rehm, R Bartolini

Copyright © 2014 CC-BY-3.0 and by the respective authors. 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 [1] 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 [2] 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.


Engineering integration constrains on the beam physics optimisation of the DDBA lattice for diamond

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 322-324

R Bartolini, M Apollonio, C Bailey, M Cox, N Hammond, R Holdsworth, J Kay, I Martin, V Smaluk, R Walker, T Pulampong

Copyright © 2014 CC-BY-3.0 and by the respective authors. The design and optimisation of the new DDBA lattice for Diamond has been performed taking fully into account, from the early stages, the geometry and the engineering integration constraints. In this paper we review the evolution of the DDBA cell, the rationale for its modification and the optimisation strategy used.


Magnet design for the diamond DDBA lattice upgrade

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 1319-1321

C Bailey, NP Hammond, R Holdsworth, J Kay, S Mhaskar, ECM Rial, RP Walker, T Pulampong, R Bartolini

Copyright © 2014 CC-BY-3.0 and by the respective authors. The DDBA lattice upgrade for Diamond presents challenging requirements on the magnet system in order to satisfy the tight constraints on the beam optics. Advanced, combined function dipole gradient and high gradient quadrupoles are needed. We present the tolerance specification, the design solutions and the measurement and alignment strategies.


Reconstruction of the time profile of 20.35 GeV, subpicosecond long electron bunches by means of coherent Smith-Purcell radiation

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 17 (2014) ARTN 052802

HL Andrews, FB Taheri, J Barros, R Bartolini, V Bharadwaj, C Clarke, N Delerue, G Doucas, N Fuster-Martinez, M Vieille-Grosjean, IV Konoplev, M Labat, S Le Corre, C Perry, A Reichold, S Stevenson


Multi-pulse laser wakefield acceleration: a new route to efficient, high-repetition-rate plasma accelerators and high flux radiation sources

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 47 (2014) ARTN 234003

SM Hooker, R Bartolini, SPD Mangles, A Tuennermann, L Corner, J Limpert, A Seryi, R Walczak


A non-linear injection kicker for Diamond light source

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 2268-2270

T Pulampong, R Bartolini

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 non-linear 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. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).


Tuning of the injector system to match possible lattice upgrades at diamond light source

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 243-245

C Christou, R Bartolini, J Kay

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 [1]. 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. Copyright © 2013 by JACoW.


Operating the diamond light source in lowalpha mode for users

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 246-248

IPS Martin, G Cinque, G Rehm, CA Thomas, R Bartolini

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 lattice was 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 lattice has 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. Copyright © 2013 by JACoW.


Loss factor and impedance analysis for the diamond storage ring

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 1826-1828

R Bartolini, R Fielder, C Thomas

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. Copyright © 2013 by JACoW.


Investigation of source point instabilities in dipole magnet based beamlines

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 3055-3057

M Apollonio, R Bartolini

At Diamond the source point in the second dipole of the Double Bend Achromats (DBA) 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. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).


Spectra of coherent smith-purcell radiation observed from short electron bunches: Numerical and experimental studies

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 801-803

FB Taheri, IV Konoplev, G Doucas, A Reichold, RJDA Smith, R Bartolini, N Delerue, H Andrews, N Fuster-Martínez, C Clarke, V Bharadwaj, PH Stoltz

To stimulate and support the progress in areas of compact particle accelerators, within research fields including X-ray and THz (T-ray) sources of radiation, 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. We use a PiC numerical model to analyse the dependence of radiated spectra dependence on the electron bunch profile, and discuss our results in the context of new experimental data from the E203 experiment at SLAC. Copyright © 2013 by JACoW.


Operating the diamond storage ring with reduced vertical emittance

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 249-251

IPS Martin, MG Abbott, M Apollonio, D Hickin, R Bartolini

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 27 pm.rad to 8 pm.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. Copyright © 2013 by JACoW.


Novel lattice upgrade studies for diamond light source

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 240-242

R Bartolini, CP Bailey, MP Cox, NP Hammond, J Kay, EC Longhi, S Mhaskar, T Pulampong, RP Walker

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. We present here the design concept and preliminary lattice design, and discuss the challenging magnet and engineering issues. Copyright © 2013 by JACoW.

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