IBIC2019 - List of Keywords (feedback)

Paper	Title	Other Keywords	Page
MOAO03	Overview on the Diagnostics for EBS-ESRF	storage-ring, SRF, radiation, diagnostics	9
	L. Torino, N. Benoist, F. Ewald, E. Plouviez, J. Poitou, B. Roche, K.B. Scheidt, F. Taoutaou, F. Uberto ESRF, Grenoble, France
	On December 2018 the ESRF was shut down and the 28 years old storage ring was entirely dismantled in the following months. A new storage ring, the Extremely Brilliant Source (EBS), that had been pre-assembled in 2017 and 2018, is presently being installed and the commissioning will start in December 2019. EBS will achieve a much reduced horizontal emittance, from 4 nm to 150 pm, and will also provide the X-ray users with a more coherent synchrotron radiation beam. In this paper, we present an overview of the diagnostics systems for this new storage ring.
	Slides MOAO03 [40.660 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOAO03
About •	paper received ※ 03 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP015	Charge Detection System for the CLARA/VELA Facility	MMI, simulation, experiment, controls	111
	S.L. Mathisen, Y.M. Saveliev, R.J. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The CLARA/VELA facility at Daresbury Laboratory combines an FEL test facility and an electron accelerator for scientific and industrial applications, capable of providing up to 40 MeV electrons, with an eventual goal of 250 MeV. Accurate measurement of the bunch charges in a wide range (1 - 250 pC) at a repetition rate up to 400 Hz is required. We present a new system of analogue electronics developed to interface with existing and future bunch charge measurement devices (wall current monitors, faraday cups, etc.) to measure the bunch charges accurately and precisely. The system is based on a charge amplifier with switchable sensitivity, dark current gating and on-board self-calibration. Results of circuit simulations, offline calibration tests and online beam tests of a prototype system are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP015
About •	paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP026	A Longitudinal Kicker Cavity for the BESSY II Booster	cavity, kicker, booster, simulation	150
	T. Atkinson, M. Dirsat, A.N. Matveenko, A. Schälicke, B. Schriefer, Y. Tamashevich HZB, Berlin, Germany T. Flisgen FBH, Berlin, Germany
	As part of the global refurbishment of the injector systems at BESSY II, a new longitudinal kicker cavity and suitable feedback will be installed in the booster. Both a flexible bunch charge and spacing is essential for efficient injection. Such a cavity is needed to mitigate the unwanted couple bunch instabilities associated with these elaborate filling patterns and the HOMs of additional accelerating structures. This paper covers the conceptual design, simulation strategy, manufacture and bench tests of the longitudinal kicker cavity before it is installed in the ring.
	Poster MOPP026 [4.756 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP026
About •	paper received ※ 02 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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MOPP027	First Beam-based Test of Fast Closed Orbit Feedback System at GSI SIS18	controls, closed-orbit, acceleration, synchrotron	154
	R. Singh, A. Doring, P. Forck, K. Lang, S.H. Mirza, D. Rodomonti, D. Schupp, M. Schwickert, H. Welker GSI, Darmstadt, Germany A. Bardorfer I-Tech, Solkan, Slovenia
	Funding: European Unions Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871 (ARIES). German Academic Exchange Service under Personal Reference No. 91605207. The SIS18 synchrotron of GSI will be used as a booster ring for the SIS100 synchrotron built in the scope of the FAIR project. In order to preserve the beam quality during the whole acceleration ramp, a new closed orbit feedback (COFB) system is implemented at the SIS18 which operates with the existing BPMs and steerer magnets. The system aims for a bandwidth of several 100 Hz and robustness against the variation of the response matrix and the beam rigidity during the ramp. The architecture of the system and the results of the first beam-based test of the COFB hardware are presented. As a first step, the orbit correction is performed over the entire ramp using the response matrix corresponding to injection energy only taking the beam rigidity into account. Experimental observations of the bandwidth limitations arising from the temporal delay of the steerer power supplies and the spatial model variation during the ramp are compared with simulations. It is found that the temporal and the spatial model mismatch have similar effect on the achievable bandwidth of the COFB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP027
About •	paper received ※ 07 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP028	Longitudinal Bunch-by-Bunch Feedback Systems for SuperKEKB LER	kicker, operation, timing, cavity	159
	M. Tobiyama, J.W. Flanagan, T. Kobayashi, S. Terui KEK, Ibaraki, Japan J.D. Fox Stanford University, Stanford, California, USA
	Longitudinal bunch-by-bunch feedback systems to suppress coupled bunch instabilities with minimum bunch spacing of 2 ns have been constructed in SuperKEKB LER. Through the grow-damp and excite-damp experiments with several filling patterns and the transient-domain analysis of unstable modes, the behaviors of possible impedance sources have been evaluated. The measured performance of the system, together with the performance of the related systems such as slow phase feedback to the reference RF clock are reported.
	Poster MOPP028 [0.519 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP028
About •	paper received ※ 03 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP030	Preliminary Test of XBPM Local Feedback in TPS	electron, photon, operation, electronics	163
	P.C. Chiu, J.-Y. Chuang, K.T. Hsu, K.H. Hu, C.H. Huang NSRRC, Hsinchu, Taiwan
	TPS is 3-GeV synchrotron light source which have opened for public users since September 2016 and now offers 400 mA top-up mode operation. The requirements of the long term orbit stability have been gradually more and more stringent. The report investigates the long-term orbit stability improved by applying local XBPM feedback.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP030
About •	paper received ※ 02 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP031	Optimisation of the ISIS Proton Synchrotron Experimental Damping System	damping, kicker, synchrotron, betatron	167
	A. Pertica, D.W. Posthuma de Boer, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J. Komppula CERN, Meyrin, Switzerland
	The ISIS Neutron and Muon Source, located in the UK, consists of a H⁻ linear accelerator, a rapid cycling proton synchrotron and two extraction lines delivering protons onto heavy metal targets. One of the limiting factors for achieving higher intensities in the accelerator is the head-tail instability present in the synchrotron, around 2ms after injection. In order to mitigate this instability, an experimental damping system is being developed for the ISIS synchrotron. Initial tests using a split electrode BPM as a pickup and a ferrite loaded kicker as a damper showed positive results. This paper describes the different developments made to the damping system and planned improvements to optimize its performance for use in normal operations.
	Poster MOPP031 [1.557 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP031
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP032	Fast Feedback Using Electron Beam Steering to Maintain the X-Ray Beam Position at a Monochromatic X-Ray Diagnostic at Diamond Light Source	electron, synchrotron, power-supply, controls	172
	C. Bloomer, G. Rehm, A. Tipper DLS, Oxfordshire, United Kingdom
	A new feedback system is being developed at Diamond Light Source, applying a modulation to the position of the electron beam to keep the synchrotron X-ray beam fixed at the sample-point. Beamline detectors operating in the 100-1000Hz regime are becoming common, and the X-ray beam stability demanded by beamlines is thus of comparable bandwidths. In this paper we present a feedback system operating at these bandwidths, using a diagnostic instrument permanently installed in the X-ray beam path to measure the error in beam position at the sample point, and fast air-cored magnets to apply a small modulation to the electron beam to compensate. Four magnets are used to generate electron beam bumps through an ID straight. This modulation of the beam away from the nominal orbit is small, less than 10 microns, but should be sufficient to compensate for the bulk of the X-ray motion observed at the sample. It is small enough that the impact on the machine will be negligible. This system aims to maintain X-ray beam stability to within 3% of a beam size, at bandwidths of up to 500Hz.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP032
About •	paper received ※ 09 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUAO01	Beam Diagnostics for Studying Beam Losses in the LHC	detector, beam-losses, proton, collimation	222
	B. Salvachua CERN, Meyrin, Switzerland
	The LHC is well covered in terms of beam loss instrumentation. Close to 4000 ionisation chambers are installed to measure global beam losses all around the LHC ring, and diamond detectors are placed at specific locations to measure bunch-by-bunch losses. Combining the information of these loss detectors with that from additional instrumentation, such as current transformers, allows for enhanced understanding and control of losses. This includes a fast and reliable beam lifetime calculation, the identification of the main origin of the loss (horizontal or vertical betatron motion or off-momentum), or a feedback to perform controlled off-momentum loss maps to validate the settings of the collimation system. This paper describes the diagnostic possibilities that open up when such measurements from several systems are combined. This is proposed as an Invited presentation from CERN Beam Instrumentation Group.
	Slides TUAO01 [9.161 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO01
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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TUPP033	Laboratory and Beam Based Studies for Assessing the Performance of the New Fast Wire Scanners for the CERN Injector Complex	controls, laser, operation, vacuum	392
	J. Emery, P. Andersson, W. Andreazza, J.M. Fernandez Ochoa, A. Goldblatt, D. Gudkov, F. Roncarolo, J.L. Sirvent, J. Tassan-Viol, R. Veness CERN, Geneva, Switzerland
	At CERN, fast beam wire scanners serve as reference transverse profile monitors in all synchrotrons. As part of the LHC Injector Upgrade project, a new generation of scanners has been designed to improve system reliability, precision and accuracy in view of higher brightness beams. This paper will discuss the performance achieved during both laboratory calibration and prototype testing with beam. The beam measurements performed in 2018 demonstrated excellent system reliability and reproducibility, while calibration in the laboratory showed that an accuracy below 10 um can be achieved on the wire position determination.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP033
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
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TUPP038	Spatial Resolution of an X-ray Pinhole Camera using a Multi-layer Monochromator	photon, emittance, simulation, synchrotron	417
	L. Bobb, G. Rehm DLS, Oxfordshire, United Kingdom
	X-ray pinhole cameras are widely used for beam emittance monitoring at synchrotron light sources. Due to the reduction in beam emittance expected for the many fourth generation machine upgrades, the spatial resolution of the pinhole camera must be improved accordingly. It is well known that there are many contributions to the point spread function. However, a significant contribution arises from diffraction by the pinhole aperture. Given that diffraction is dependent on the spectral distribution of the incident synchrotron radiation, the spatial resolution can be improved by using a monochromatic beam. For optimal performance, the photon energy should be matched to the pinhole aperture size. Here we investigate the spatial resolution of the pinhole camera as a function of photon energy using a multi-layer monochromator.
	Poster TUPP038 [0.617 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP038
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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WECO01	Characterisation of Closed Orbit Feedback Systems	controls, synchrotron, electron, hadron	479
	G. Rehm DLS, Oxfordshire, United Kingdom
	Closed orbit feedback is applied at nearly all synchrotrons. Detailed investigations continue to be performed on the mathematical modelling of the spatial part (i.e. related to Orbit Response Matrix) and the dynamic part (i.e. the controller). This talk will serve as a summary of the ARIES workshop on closed orbit feedback organized by ALBA in November 2018. Benefits of recent advances compared to the traditional implementations will be highlighted.
	Slides WECO01 [4.912 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO01
About •	paper received ※ 06 September 2019 paper accepted ※ 20 November 2019 issue date ※ 10 November 2019
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WECO02	Towards an Adaptive Orbit-Response-Matrix Model for Twiss-Parameter Diagnostics and Orbit Correction at Delta	betatron, storage-ring, closed-orbit, electron	485
	S. Koetter, T. Weis DELTA, Dortmund, Germany
	At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, preliminary tests of an adaptive orbit-response-matrix model were conducted. Closed orbit perturbations corrected by the slow orbit feedback can be buffered and used to update a fit of the bilinear-exponential model with dispersion (BE+d model). This model is a representation of the orbit-response matrix depending on the beta functions, the betatron phases and the tunes in both planes. This work introduces a new fitting recipe to obtain good estimates of the aforementioned quantities and evaluates a BE+d-model represented orbit-response matrix for orbit correction. Numerical studies are shown along with measurement results.
	Slides WECO02 [0.657 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO02
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WECO03	Tune Computation via Model Fitting to Swept Machine Response Measurement	synchrotron, operation, resonance, betatron	490
	M.G. Abbott, G. Rehm DLS, Oxfordshire, United Kingdom
	At Diamond Light Source we compute the horizontal and vertical tunes by fitting a simple multi-pole resonator model to the measured electron beam frequency response. The transverse (and longitudinal) tune response is measured by sweeping an excitation across the range of possible tune frequencies and synchronously measuring the IQ response. The multi-pole resonator model is a good fit to the measured behaviour, but the fitting process is surprisingly challenging. Problems include noisy measurements, very complex beam responses in the presence of increasing chromaticity, poor data when the beam is close to instability, and a number of challenges with the stability of the algorithm. The tune fitting algorithm now in use at Diamond has been developed and refined over many years. It is finally stable enough to work reliably throughout most beam operating conditions. The algorithm involves alternating peak finding and non-linear fitting, with a fairly naive mathematical approach; the main focus is on providing reliable results.
	Slides WECO03 [1.059 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO03
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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THAO02	Towards Full Silicon 4H-SiC Based X-Ray Beam Monitoring	storage-ring, synchrotron, experiment, monitoring	665
	M. Camarda, M. Birri, M. Carulla, D. Grolimund, B. Meyer, C. Pradervand PSI, Villigen PSI, Switzerland U. Grossner, S.M. Nida, A. Tsibizov, T. Ziemann ETH, Zurich, Switzerland
	In this work, we present extensive theoretical and experimental results of novel Silicon Carbide x-ray sensors for beam position monitoring (XBPM). Until recently, diamond, was considered the material-of-choice for continuous monitoring of hard (>6keV) x-ray beams at synchrotron light sources. Diamond XBPM are now commercially available as single crystal* and polycrystalline sensors. However, in a recently published paper, we have shown that Silicon Carbide is superior to both diamond crystal types in several critical aspects. Specifically, we found superior electrical characteristics (sensor dynamics, signal uniformity, signal strength) and superior optical properties (full device transparency, device active area, signal strength) when compared to commercial polycrystalline and single crystal diamond, respectively. We also succeeded in the ¿industrialization¿ of the SiC fabrication process, allowing for the simultaneous realization of several (>40) sensors in up to 4¿ SiC wafers, with high yields. More recently we have also analyzed the fluorescence of SiC sensors as compared to YAG ones, finding that SiC can also be used for hybrid position/shape monitoring schema. CIVIDEC. AT, SYDORTECHNOLOGIES. COM DECTRIS. COM * S. Nida, et. al. Silicon carbide X-ray beam position monitors for synchrotron applications J. Synchrotron Rad. 26, 28-35 (2019)
	Slides THAO02 [9.963 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-THAO02
About •	paper received ※ 11 September 2019 paper accepted ※ 11 September 2019 issue date ※ 10 November 2019
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Paper

Title

Other Keywords

Page

MOAO03

Overview on the Diagnostics for EBS-ESRF

storage-ring, SRF, radiation, diagnostics

9

L. Torino, N. Benoist, F. Ewald, E. Plouviez, J. Poitou, B. Roche, K.B. Scheidt, F. Taoutaou, F. Uberto
ESRF, Grenoble, France

On December 2018 the ESRF was shut down and the 28 years old storage ring was entirely dismantled in the following months. A new storage ring, the Extremely Brilliant Source (EBS), that had been pre-assembled in 2017 and 2018, is presently being installed and the commissioning will start in December 2019. EBS will achieve a much reduced horizontal emittance, from 4 nm to 150 pm, and will also provide the X-ray users with a more coherent synchrotron radiation beam. In this paper, we present an overview of the diagnostics systems for this new storage ring.

Slides MOAO03 [40.660 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOAO03

About •

paper received ※ 03 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP015

Charge Detection System for the CLARA/VELA Facility

MMI, simulation, experiment, controls

111

S.L. Mathisen, Y.M. Saveliev, R.J. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The CLARA/VELA facility at Daresbury Laboratory combines an FEL test facility and an electron accelerator for scientific and industrial applications, capable of providing up to 40 MeV electrons, with an eventual goal of 250 MeV. Accurate measurement of the bunch charges in a wide range (1 - 250 pC) at a repetition rate up to 400 Hz is required. We present a new system of analogue electronics developed to interface with existing and future bunch charge measurement devices (wall current monitors, faraday cups, etc.) to measure the bunch charges accurately and precisely. The system is based on a charge amplifier with switchable sensitivity, dark current gating and on-board self-calibration. Results of circuit simulations, offline calibration tests and online beam tests of a prototype system are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP015

About •

paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP026

A Longitudinal Kicker Cavity for the BESSY II Booster

cavity, kicker, booster, simulation

150

T. Atkinson, M. Dirsat, A.N. Matveenko, A. Schälicke, B. Schriefer, Y. Tamashevich
HZB, Berlin, Germany
T. Flisgen
FBH, Berlin, Germany

As part of the global refurbishment of the injector systems at BESSY II, a new longitudinal kicker cavity and suitable feedback will be installed in the booster. Both a flexible bunch charge and spacing is essential for efficient injection. Such a cavity is needed to mitigate the unwanted couple bunch instabilities associated with these elaborate filling patterns and the HOMs of additional accelerating structures. This paper covers the conceptual design, simulation strategy, manufacture and bench tests of the longitudinal kicker cavity before it is installed in the ring.

Poster MOPP026 [4.756 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP026

About •

paper received ※ 02 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP027

First Beam-based Test of Fast Closed Orbit Feedback System at GSI SIS18

controls, closed-orbit, acceleration, synchrotron

154

R. Singh, A. Doring, P. Forck, K. Lang, S.H. Mirza, D. Rodomonti, D. Schupp, M. Schwickert, H. Welker
GSI, Darmstadt, Germany
A. Bardorfer
I-Tech, Solkan, Slovenia

Funding: European Unions Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871 (ARIES). German Academic Exchange Service under Personal Reference No. 91605207.
The SIS18 synchrotron of GSI will be used as a booster ring for the SIS100 synchrotron built in the scope of the FAIR project. In order to preserve the beam quality during the whole acceleration ramp, a new closed orbit feedback (COFB) system is implemented at the SIS18 which operates with the existing BPMs and steerer magnets. The system aims for a bandwidth of several 100 Hz and robustness against the variation of the response matrix and the beam rigidity during the ramp. The architecture of the system and the results of the first beam-based test of the COFB hardware are presented. As a first step, the orbit correction is performed over the entire ramp using the response matrix corresponding to injection energy only taking the beam rigidity into account. Experimental observations of the bandwidth limitations arising from the temporal delay of the steerer power supplies and the spatial model variation during the ramp are compared with simulations. It is found that the temporal and the spatial model mismatch have similar effect on the achievable bandwidth of the COFB.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP027

About •

paper received ※ 07 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP028

Longitudinal Bunch-by-Bunch Feedback Systems for SuperKEKB LER

kicker, operation, timing, cavity

159

M. Tobiyama, J.W. Flanagan, T. Kobayashi, S. Terui
KEK, Ibaraki, Japan
J.D. Fox
Stanford University, Stanford, California, USA

Longitudinal bunch-by-bunch feedback systems to suppress coupled bunch instabilities with minimum bunch spacing of 2 ns have been constructed in SuperKEKB LER. Through the grow-damp and excite-damp experiments with several filling patterns and the transient-domain analysis of unstable modes, the behaviors of possible impedance sources have been evaluated. The measured performance of the system, together with the performance of the related systems such as slow phase feedback to the reference RF clock are reported.

Poster MOPP028 [0.519 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP028

About •

paper received ※ 03 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP030

Preliminary Test of XBPM Local Feedback in TPS

electron, photon, operation, electronics

163

P.C. Chiu, J.-Y. Chuang, K.T. Hsu, K.H. Hu, C.H. Huang
NSRRC, Hsinchu, Taiwan

TPS is 3-GeV synchrotron light source which have opened for public users since September 2016 and now offers 400 mA top-up mode operation. The requirements of the long term orbit stability have been gradually more and more stringent. The report investigates the long-term orbit stability improved by applying local XBPM feedback.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP030

About •

paper received ※ 02 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP031

Optimisation of the ISIS Proton Synchrotron Experimental Damping System

damping, kicker, synchrotron, betatron

167

A. Pertica, D.W. Posthuma de Boer, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J. Komppula
CERN, Meyrin, Switzerland

The ISIS Neutron and Muon Source, located in the UK, consists of a H⁻ linear accelerator, a rapid cycling proton synchrotron and two extraction lines delivering protons onto heavy metal targets. One of the limiting factors for achieving higher intensities in the accelerator is the head-tail instability present in the synchrotron, around 2ms after injection. In order to mitigate this instability, an experimental damping system is being developed for the ISIS synchrotron. Initial tests using a split electrode BPM as a pickup and a ferrite loaded kicker as a damper showed positive results. This paper describes the different developments made to the damping system and planned improvements to optimize its performance for use in normal operations.

Poster MOPP031 [1.557 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP031

About •

paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPP032

Fast Feedback Using Electron Beam Steering to Maintain the X-Ray Beam Position at a Monochromatic X-Ray Diagnostic at Diamond Light Source

electron, synchrotron, power-supply, controls

172

C. Bloomer, G. Rehm, A. Tipper
DLS, Oxfordshire, United Kingdom

A new feedback system is being developed at Diamond Light Source, applying a modulation to the position of the electron beam to keep the synchrotron X-ray beam fixed at the sample-point. Beamline detectors operating in the 100-1000Hz regime are becoming common, and the X-ray beam stability demanded by beamlines is thus of comparable bandwidths. In this paper we present a feedback system operating at these bandwidths, using a diagnostic instrument permanently installed in the X-ray beam path to measure the error in beam position at the sample point, and fast air-cored magnets to apply a small modulation to the electron beam to compensate. Four magnets are used to generate electron beam bumps through an ID straight. This modulation of the beam away from the nominal orbit is small, less than 10 microns, but should be sufficient to compensate for the bulk of the X-ray motion observed at the sample. It is small enough that the impact on the machine will be negligible. This system aims to maintain X-ray beam stability to within 3% of a beam size, at bandwidths of up to 500Hz.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP032

About •

paper received ※ 09 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUAO01

Beam Diagnostics for Studying Beam Losses in the LHC

detector, beam-losses, proton, collimation

222

B. Salvachua
CERN, Meyrin, Switzerland

The LHC is well covered in terms of beam loss instrumentation. Close to 4000 ionisation chambers are installed to measure global beam losses all around the LHC ring, and diamond detectors are placed at specific locations to measure bunch-by-bunch losses. Combining the information of these loss detectors with that from additional instrumentation, such as current transformers, allows for enhanced understanding and control of losses. This includes a fast and reliable beam lifetime calculation, the identification of the main origin of the loss (horizontal or vertical betatron motion or off-momentum), or a feedback to perform controlled off-momentum loss maps to validate the settings of the collimation system. This paper describes the diagnostic possibilities that open up when such measurements from several systems are combined.
This is proposed as an Invited presentation from CERN Beam Instrumentation Group.

Slides TUAO01 [9.161 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO01

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paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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TUPP033

Laboratory and Beam Based Studies for Assessing the Performance of the New Fast Wire Scanners for the CERN Injector Complex

controls, laser, operation, vacuum

392

J. Emery, P. Andersson, W. Andreazza, J.M. Fernandez Ochoa, A. Goldblatt, D. Gudkov, F. Roncarolo, J.L. Sirvent, J. Tassan-Viol, R. Veness
CERN, Geneva, Switzerland

At CERN, fast beam wire scanners serve as reference transverse profile monitors in all synchrotrons. As part of the LHC Injector Upgrade project, a new generation of scanners has been designed to improve system reliability, precision and accuracy in view of higher brightness beams. This paper will discuss the performance achieved during both laboratory calibration and prototype testing with beam. The beam measurements performed in 2018 demonstrated excellent system reliability and reproducibility, while calibration in the laboratory showed that an accuracy below 10 um can be achieved on the wire position determination.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP033

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paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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TUPP038

Spatial Resolution of an X-ray Pinhole Camera using a Multi-layer Monochromator

photon, emittance, simulation, synchrotron

417

L. Bobb, G. Rehm
DLS, Oxfordshire, United Kingdom

X-ray pinhole cameras are widely used for beam emittance monitoring at synchrotron light sources. Due to the reduction in beam emittance expected for the many fourth generation machine upgrades, the spatial resolution of the pinhole camera must be improved accordingly. It is well known that there are many contributions to the point spread function. However, a significant contribution arises from diffraction by the pinhole aperture. Given that diffraction is dependent on the spectral distribution of the incident synchrotron radiation, the spatial resolution can be improved by using a monochromatic beam. For optimal performance, the photon energy should be matched to the pinhole aperture size. Here we investigate the spatial resolution of the pinhole camera as a function of photon energy using a multi-layer monochromator.

Poster TUPP038 [0.617 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP038

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paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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WECO01

Characterisation of Closed Orbit Feedback Systems

controls, synchrotron, electron, hadron

479

G. Rehm
DLS, Oxfordshire, United Kingdom

Closed orbit feedback is applied at nearly all synchrotrons. Detailed investigations continue to be performed on the mathematical modelling of the spatial part (i.e. related to Orbit Response Matrix) and the dynamic part (i.e. the controller). This talk will serve as a summary of the ARIES workshop on closed orbit feedback organized by ALBA in November 2018. Benefits of recent advances compared to the traditional implementations will be highlighted.

Slides WECO01 [4.912 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO01

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paper received ※ 06 September 2019 paper accepted ※ 20 November 2019 issue date ※ 10 November 2019

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WECO02

Towards an Adaptive Orbit-Response-Matrix Model for Twiss-Parameter Diagnostics and Orbit Correction at Delta

betatron, storage-ring, closed-orbit, electron

485

S. Koetter, T. Weis
DELTA, Dortmund, Germany

At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, preliminary tests of an adaptive orbit-response-matrix model were conducted. Closed orbit perturbations corrected by the slow orbit feedback can be buffered and used to update a fit of the bilinear-exponential model with dispersion (BE+d model). This model is a representation of the orbit-response matrix depending on the beta functions, the betatron phases and the tunes in both planes. This work introduces a new fitting recipe to obtain good estimates of the aforementioned quantities and evaluates a BE+d-model represented orbit-response matrix for orbit correction. Numerical studies are shown along with measurement results.

Slides WECO02 [0.657 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO02

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paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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WECO03

Tune Computation via Model Fitting to Swept Machine Response Measurement

synchrotron, operation, resonance, betatron

490

M.G. Abbott, G. Rehm
DLS, Oxfordshire, United Kingdom

At Diamond Light Source we compute the horizontal and vertical tunes by fitting a simple multi-pole resonator model to the measured electron beam frequency response. The transverse (and longitudinal) tune response is measured by sweeping an excitation across the range of possible tune frequencies and synchronously measuring the IQ response. The multi-pole resonator model is a good fit to the measured behaviour, but the fitting process is surprisingly challenging. Problems include noisy measurements, very complex beam responses in the presence of increasing chromaticity, poor data when the beam is close to instability, and a number of challenges with the stability of the algorithm. The tune fitting algorithm now in use at Diamond has been developed and refined over many years. It is finally stable enough to work reliably throughout most beam operating conditions. The algorithm involves alternating peak finding and non-linear fitting, with a fairly naive mathematical approach; the main focus is on providing reliable results.

Slides WECO03 [1.059 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO03

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paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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THAO02

Towards Full Silicon 4H-SiC Based X-Ray Beam Monitoring

storage-ring, synchrotron, experiment, monitoring

665

M. Camarda, M. Birri, M. Carulla, D. Grolimund, B. Meyer, C. Pradervand
PSI, Villigen PSI, Switzerland
U. Grossner, S.M. Nida, A. Tsibizov, T. Ziemann
ETH, Zurich, Switzerland

In this work, we present extensive theoretical and experimental results of novel Silicon Carbide x-ray sensors for beam position monitoring (XBPM). Until recently, diamond, was considered the material-of-choice for continuous monitoring of hard (>6keV) x-ray beams at synchrotron light sources. Diamond XBPM are now commercially available as single crystal* and polycrystalline** sensors. However, in a recently published paper***, we have shown that Silicon Carbide is superior to both diamond crystal types in several critical aspects. Specifically, we found superior electrical characteristics (sensor dynamics, signal uniformity, signal strength) and superior optical properties (full device transparency, device active area, signal strength) when compared to commercial polycrystalline and single crystal diamond, respectively. We also succeeded in the ¿industrialization¿ of the SiC fabrication process, allowing for the simultaneous realization of several (>40) sensors in up to 4¿ SiC wafers, with high yields. More recently we have also analyzed the fluorescence of SiC sensors as compared to YAG ones, finding that SiC can also be used for hybrid position/shape monitoring schema.
* CIVIDEC. AT, SYDORTECHNOLOGIES. COM
** DECTRIS. COM
*** S. Nida, et. al. Silicon carbide X-ray beam position monitors for synchrotron applications J. Synchrotron Rad. 26, 28-35 (2019)

Slides THAO02 [9.963 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-THAO02

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paper received ※ 11 September 2019 paper accepted ※ 11 September 2019 issue date ※ 10 November 2019

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