IBIC2012 - List of Keywords (storage-ring)

Paper	Title	Other Keywords	Page
MOCB03	Modeling and Performance Evaluation of DCCTs in SSRF	shielding, instrumentation, booster, electromagnetic-fields	16
	Z.C. Chen, Y.B. Leng, Y. Xiong, W.M. Zhou SSRF, Shanghai, People's Republic of China
	Direct Current Current Transformer (DCCT) is the most commonly used high precision current monitor in modern particle accelerators including Shanghai Synchrotron Radiation Facility (SSRF). Three types of noise have been observed in the output signal of the DCCT in the storage ring of SSRF: power line noise, beam current related narrow band noise and random square wave noise from nowhere. This article will discuss the noise removal algorithms in SSRF and the performance of the DCCTs afterwards.
	Slides MOCB03 [1.436 MB]

MOPA21	Improvement of the SIAM Photon Source Storage Ring BPM System	shielding, photon, feedback, operation	101
	S. Klinkhieo, S. Boonsuya, P. Klysubun, S. Krainara, P. Songsiriritthigul, P. Sudmuang, N. Suradet, S. Tesprasitte SLRI, Nakhon Ratchasima, Thailand J.-R. Chen, H.P. Hsueh, Y.-H. Liu NSRRC, Hsinchu, Taiwan
	This report describes the improvement of the Beam Position Monitoring (BPM) systems for the 1.2 GeV storage ring of the Siam Photon Source (SPS). The systematic studies and investigations for improving the machine performance, and storage ring BPM system has been carried out in the last few years. Some major technical problems have been found and solved. The inefficiency and unreliability of the original BPM system were also identified. They are mainly caused due to the use of low quality signal and improper installation of cables. Detailed descriptions of the replacement with the higher quality (lower loss and better interference shielding) BPM cables and implementation of a separated cable trays for the BPM cables, as well as the work on BPM electronic board calibration will be described. The measurement results before and after the improvement of the BPM system will also be presented.

MOPA28	Turn-by-turn BPM System using Coaxial Switches and ARM Microcontroller at UVSOR	controls, electron, injection, betatron	112
	T. Toyoda IMS, Okazaki, Japan K. Hayashi, M. Katoh UVSOR, Okazaki, Japan
	A major upgrade of the electron storage ring at UVSOR (Institute for Molecular Science, Japan) started from April 2012. To assist the commissioning procedure, we have developed a turn-by-turn Beam Position Monitor (BPM) system which consists of a signal switching circuit, a digital oscilloscope and software. The storage ring has 24 BPMs, each of which consists of four electrodes. By using the signal switching circuit, we can select one BPM from eight BPM's. The four signals from the BPM are sent to a digital oscilloscope and are recorded. In the switching circuit, coaxial switches of SPDT (Single Pole Dual Throw) and SP4T type are used. To control coaxial switches, we adopted 'mbed', the ARM microcontroller development kit. The 'mbed' stores the control applications configured in the HTML file and JavaScript library which can handle multiple I/O ports. It responds as a HTTP server and the control application runs on a Web browser. By clicking buttons with a mouse, we can control the I/O ports of 'mbed' through JavaScript library and accordingly can control coaxial switches. In the presentation, we will report the detail of the developed BPM system and its performance.

MOPA34	Improvement of Hardware and Software Setup for the Acquisition and Processing of SIAM Photon Source BPM Signal	photon, PLC, feedback, software	130
	N. Suradet, S. Boonsuya, S. Klinkhieo, P. Klysubun, S. Krainara, C.P. Preecha, P. Sudmuang SLRI, Nakhon Ratchasima, Thailand
	Data acquisition and processing system has been developed for the Siam Photon Source storage ring BPM system in order to improve monitoring and logging performances. BPM readout, i.e. scanning of BPM electrode voltage outputs and subsequently converting to X-Y position values, is now performed by an upgraded Programmable Logic Controller (PLC) with higher bit resolution (16-bit) analog-to-digital converter (ADC). Moving averaging is then performed on the obtained BPM data utilizing a LabVIEW code to reduce background noise during on-line measurement. All data is then stored on a dedicated computer serving as a central data logging system, which can be remotely accessed via a network communication link. In this report, details of the new setup will be presented, and comparison will be made between the performance of the new and previous setups, together with suggestions on further improvements.

MOPB52	Status and Activities of the SPring-8 Diagnostics Beamlines	photon, diagnostics, optics, emittance	186
	S. Takano, M. Masaki, A. Mochihashi, H. Ohkuma, M. Shoji, K. Tamura JASRI/SPring-8, Hyogo-ken, Japan H. Sumitomo, M. Yoshioka SES, Hyogo-pref., Japan
	At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress.

MOPB56	Electron Cloud Measurements using a Time Resolved Retarding Field Analyzer at CesrTA	electron, detector, dipole, positron	201
	J.P. Sikora, M.G. Billing, J.V. Conway, J.A. Crittenden, Y. Li, X. Liu, D. L. Rubin, C.R. Strohman CLASSE, Ithaca, New York, USA K. Kanazawa KEK, Ibaraki, Japan M.A. Palmer Fermilab, Batavia, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, the US Department of Energy DE-FC02-08ER41538, DE-SC0006505 and US-Japan funding. The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV. An area of research at CesrTA is the study of the growth, decay and mitigation of electron clouds in the storage ring. With a Retarding Field Analyzer (RFA), cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The electrons are captured by several collectors, so that the electron flux can be measured vs. horizontal position. Up to now, we have integrated the collector currents to provide DC measurements. We have recently constructed a new Time Resolved RFA, where the collector currents can be observed on the time scale of the bunch train in the storage ring. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements at CesrTA.

MOPB83	Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring	injection, synchrotron, timing, electron	276
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process.

MOPB86	Betatron Tune Measurement and Automatic Correction Systems at NewSUBARU Storage Ring	operation, betatron, survey, synchrotron	283
	S. Hashimoto, Y. Hamada, S. Miyamoto LASTI, Hyogo, Japan
	At the 1.5GeV electron storage ring NewSUBARU, the two different kinds of systems for measuring betatron tunes have been developed: the high precision tune monitor and that for automatic correction. The vertical and horizontal tunes can be observed during the user time, because a stripe-line kicker to enlarge the beam lifetime vertically shakes electron beams. The high-precision tune monitor has the resolution of 0.0002 and uses frequency analysis methods such as SRSA, zoom FFT, STFT, in addition to usual FFT. Tune shifts due to a slight difference of filling patterns during top-up operations can be observed with this monitor. The another tune monitoring and automatic-correcting system has been developed to compensate tune shifts caused by the decrease of the stored current, the difference of filling patterns during top-up operations, and the energy ramp from 1.0 to 1.5 GeV. This system estimates betatron tunes every 0.5 sec and can keep tunes to the optimal values. The system also has a tune survey function that can automatically measure the beam lifetime in a tune diagram.

TUCC03	Design and Expected Performance of the New SLS Beam Size Monitor	emittance, polarization, synchrotron, synchrotron-radiation	307
	N. Milas, M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun PSI, Villigen PSI, Switzerland Å. Andersson, J. Breunlin MAX-lab, Lund, Sweden
	The vertical emittance minimization campaign at SLS, realized in the context of the TIARA WP6, has already achieved the world's smallest vertical emittance of 0.9 pm in a synchrotron light source. The minimum value reached for the vertical emittance is only five times bigger than the quantum limit of 0.2 pm. However, the resolution limit of the present SLS emittance monitor has also been reached thus, to further continue the emittance minimization program the construction of an improved second monitor is necessary. In this paper we present the design and studies on the performance of this new monitor based on the image formation method using vertically polarized synchrotron radiation in the vis-UV spectral regimes. This monitor includes a new feature, providing the possibility of performing full interferometric measurement by the use of a set of vertical obstacles that can be driven on the light path. Simulations results are used to investigate the possible source of errors and their effects on imaging and the determination of the beam height. We also present the expected performance, in term of emittance accuracy and precision, and discuss possible design limitations.
	Slides TUCC03 [8.497 MB]

TUPA01	Diagnostics Update of the Taiwan Photon Source	feedback, diagnostics, booster, synchrotron	324
	C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a 3 GeV synchrotron light source which is being construction at campus of NSRRC. Various diagnostics are in implementation and will deploy in the future to satisfy stringent requirements of TPS for commissioning, top-up injection, and operation. These designs include beam intensity observation, trajectory and beam positions measurement, destructive profile measurement, synchrotron radiation monitors, beam loss monitors, orbit and bunch-by-bunch feedbacks, filling pattern and etc. are in final design phase. Progress of construction of the planned beam instrumentation system for the TPS will be summarized in this report.

TUPA05	The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System	pick-up, experiment, data-analysis, electron	334
	Y.L. Yang, C. Cheng, P. Lu, T.J. Ma, B.G. Sun, J.G. Wang, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by National Natural Science Project(11105141) and Chinese Universities Scientific Fund For bunch current measurement, the calibration factor is a key parameter. Usually, button electrode or stripline electrode can be selected as signal pickup, and peak value or integral of bunch signal from pickup can be used to calculate the related bunch current value. To obtain the absolute value of bunch current, the calibration factor should be determined with the help of DCCT. At HLS, the Stretch effect of bunch length was observed when bunch current decay over time and this will affect the performance of bunch current detection for different pickup type and calculate method. Theoretical analysis and experimental validation results are performed to find out an ideal solution for bunch current measurement at HLS. The results show that, bunch current measurement system can obtain the best performance by stripline and its integral signal.

TUPA07	BPM Selection for Beam Current Monitoring in SSRF	monitoring, operation, experiment, instrumentation	341
	Z.C. Chen, Y.B. Leng, Y.B. Yan SSRF, Shanghai, People's Republic of China
	Although Direct Current Current Transformer (DCCT) is the general solution of beam current monitor, Beam Position Monitor (BPM) sum signals may still surpass it in some aspects such as the faster data rate and higher resolution in low current situations. Nevertheless, an additional monitor should be harmless. Meanwhile, the DCCTs in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been suffering from various noise and the signals from the BPMs could be an aid to provide the beam current more accurately. There're 140 BPMs in the storage ring in SSRF but not all of them are suitable for this particular usage. This article focuses on the methods used here to dynamicly choose the BPMs that meet the criteria.

TUPA10	Optical-Fiber Beam Loss Monitor for the KEK Photon Factory	injection, vacuum, electron, kicker	351
	T. Obina, Y. Yano KEK, Ibaraki, Japan
	Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

TUPA33	Fast Orbit Feedback Calculation Implementation for TPS	brilliance, controls, feedback, FPGA	428
	P. Leban, A. Bardorfer I-Tech, Solkan, Slovenia K.T. Hsu, C.H. Kuo NSRRC, Hsinchu, Taiwan
	Fast orbit feedback (FOFB) application is planned for the Taiwan Photon Source (TPS) at storage ring commissioning. Part of the application is transferred to the beam position electronics which implements global orbit position data concentration, its processing and actuating the magnet power supply controllers via optical links. The beam position electronics (Libera Brilliance+) includes gigabit data exchange (GDX) modules with Virtex6 field programmable gate array. The feedback calculation algorithm is based on the SVD ' the PI controller will be applied in the modal space for individual eigenmodes. The calculation will be distributed to all GDX modules to reduce overall latency. Each GDX module will calculate either 4 vertical or 4 horizontal magnet corrections. This article presents details about the FOFB topology and implementation in the GDX module.

TUPA35	Digital Longitudinal Bunch-by-bunch Feedback System for the HLS II	kicker, feedback, cavity, impedance	434
	W.B. Li, P. Lu, B.G. Sun, F.F. Wu, W. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to suppress the longitudinal coupled bunch instabilities, a digital longitudinal bunch-by-bunch feedback system will be developed in the upgrade project of Hefei Light Source (HLS II). The longitudinal feedback system consists of a pickup BPM, a front-end signal processor unit to detect the phase errors of all electron bunches, an iGp signal processor to calculate correction signals of those bunches, two RF power amplifiers, and a longitudinal kicker to supply proper correction energy kicks to individual bunches. A new waveguide overloaded cavity longitudinal feedback kicker has been designed with broadband and high shunt impedance. In this paper, we describe an overview of the new longitudinal feedback system.

TUPA46	Streak Camera Measurements at ALBA: Bunch Length and Energy Matching	injection, booster, synchrotron, damping	458
	U. Iriso, F.F.B. Fernández CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	This report describes the electron beam longitudinal studies performed at ALBA Storage Ring using the streak camera. We first show the usual studies involving precise bunch length measurements and related beam parameters like energy spread or momentum compaction factor. Next, the studies to match the injected beam in energy and phase are reported and compared with simulations.

TUPB49	Electron Cloud Density Measurements using Resonant TE Waves at CesrTA	resonance, electron, simulation, positron	471
	J.P. Sikora, M.G. Billing, D.O. Duggins, Y. Li, D. L. Rubin, R.M. Schwartz, K.G. Sonnad CLASSE, Ithaca, New York, USA S. De Santis LBNL, Berkeley, California, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam.

TUPB72	Injected Beam Profile Measurement during Top-up Operation	injection, operation, background, timing	508
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	A coronagraph-like apparatus was constructed on the optical diagnostic beamline on the storage ring to observe the injected beam during top-up operations. An image was created on an intensified CCD that can be gated on a single bunch or on a bunch train for a stronger signal. The bright central stored beam was obscured so the comparatively faint injected beam could be observed. The injected beam comes in at a large enough offset so that it was clearly visible above any diffraction or beam halo signals. The beam profile measured was in good agreement with the observations made of the injected beam only using a telescope apparatus. The measurements were made during user beam in top-up operation mode and can be used to optimise the injection process.

TUPB77	Measurement of the Frequency Spectrum on the Beam Profile Controlled by RF Kicker	radiation, betatron, detector, operation	524
	Y. Yamamoto Ritsumeikan University, Kusatsu-City, Shiga, Japan
	The frequency spectrum on the beam profile was measured at the compact superconducting storage ring of Ritsumeikan University. The radiation detector was used an avalanche photodiode module with a high frequency response of 1 GHz for the visible ray. Signals from the detector were transferred to a spectrum analyzer. The beam profile was magnified strongly by a conventional profile monitor system. We scanned the beam profile in vertical direction by shifting the detector. The distribution of peak intensity as a function of the position on beam profile was obtained.

TUPB84	Storage Ring Tune Measurements using High-speed Metal-semiconductor-metal Photodetector	synchrotron, coupling, detector, electron	537
	S. Dawson, D.J. Peake, R.P. Rassool The University of Melbourne, Melbourne, Australia M.J. Boland ASCo, Clayton, Victoria, Australia R.J. Steinhagen CERN, Geneva, Switzerland
	Knowledge of the betatron tunes within a storage ring is important to prevent the creation of instabilities and maximise the lifetime of the stored current within the ring. Typical tune measurements excite the beam and measure the resulting motion over time using electromagnetic pickups. The novel measurement technique presented utilises high-speed MSM photodiodes in a balanced detector set-up to measure the vertical and horizontal betatron tunes. Radiation from a bending magnet consists of both visible light and X-rays. The visible light is separated from the X-rays with an optical chicane and focussed onto a pair of length-matched optical fibers each coupled to an MSM photodiode. The specialised biasing circuit for the photodiodes is constructed in a balanced detector configuration to emphasise any motion in the beam. Signal resulting from beam motion is amplified and digitised for analysis. Using this set-up the tunes for the storage ring at the Australian Synchrotron have been measured and verified with comparison to existing tune measurement technologies. The results from the new optical tune measurement system will be presented and discussed.

TUPB85	Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm	injection, electron, wakefield, experiment	540
	Y. Yang, Y.B. Leng SSRF, Shanghai, People's Republic of China B.P. Wang SINAP, Shanghai, People's Republic of China
	Based on the spectrum of turn-by-turn model for the storage ring, spectrum of multi-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve.

WECC03	Intensity Imbalance Optical Interferometer Beam Size Monitor	diagnostics, synchrotron, coupling, damping	566
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi, T. Naito KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	The technique of measuring the beam size in a particle accelerator with an optical interferometer with the Mitsuhashi apparatus is well established and one of the only direct measurement techniques available. However, one of the limitations of the technique is the dynamic range and noise level of CCD cameras when measuring ultra low emittance beams and hence visibilities close to unity. A new design has been successfully tested to overcome these limitations by introducing a know intensity imbalance in one of the light paths of the interferometer. This modification reduces the visibility in a controlled way and lifts the measured interference pattern out of the noise level of the CCD, thus increasing the dynamic range of the apparatus. Results are presented from tests at the ATF2 at KEK and on the optical diagnostic beamline at the Australian Synchrotron storage ring.
	Slides WECC03 [2.383 MB]

Paper

Title

Other Keywords

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MOCB03

Modeling and Performance Evaluation of DCCTs in SSRF

shielding, instrumentation, booster, electromagnetic-fields

16

Z.C. Chen, Y.B. Leng, Y. Xiong, W.M. Zhou
SSRF, Shanghai, People's Republic of China

Direct Current Current Transformer (DCCT) is the most commonly used high precision current monitor in modern particle accelerators including Shanghai Synchrotron Radiation Facility (SSRF). Three types of noise have been observed in the output signal of the DCCT in the storage ring of SSRF: power line noise, beam current related narrow band noise and random square wave noise from nowhere. This article will discuss the noise removal algorithms in SSRF and the performance of the DCCTs afterwards.

Slides MOCB03 [1.436 MB]

MOPA21

Improvement of the SIAM Photon Source Storage Ring BPM System

shielding, photon, feedback, operation

101

S. Klinkhieo, S. Boonsuya, P. Klysubun, S. Krainara, P. Songsiriritthigul, P. Sudmuang, N. Suradet, S. Tesprasitte
SLRI, Nakhon Ratchasima, Thailand
J.-R. Chen, H.P. Hsueh, Y.-H. Liu
NSRRC, Hsinchu, Taiwan

This report describes the improvement of the Beam Position Monitoring (BPM) systems for the 1.2 GeV storage ring of the Siam Photon Source (SPS). The systematic studies and investigations for improving the machine performance, and storage ring BPM system has been carried out in the last few years. Some major technical problems have been found and solved. The inefficiency and unreliability of the original BPM system were also identified. They are mainly caused due to the use of low quality signal and improper installation of cables. Detailed descriptions of the replacement with the higher quality (lower loss and better interference shielding) BPM cables and implementation of a separated cable trays for the BPM cables, as well as the work on BPM electronic board calibration will be described. The measurement results before and after the improvement of the BPM system will also be presented.

MOPA28

Turn-by-turn BPM System using Coaxial Switches and ARM Microcontroller at UVSOR

controls, electron, injection, betatron

112

T. Toyoda
IMS, Okazaki, Japan
K. Hayashi, M. Katoh
UVSOR, Okazaki, Japan

A major upgrade of the electron storage ring at UVSOR (Institute for Molecular Science, Japan) started from April 2012. To assist the commissioning procedure, we have developed a turn-by-turn Beam Position Monitor (BPM) system which consists of a signal switching circuit, a digital oscilloscope and software. The storage ring has 24 BPMs, each of which consists of four electrodes. By using the signal switching circuit, we can select one BPM from eight BPM's. The four signals from the BPM are sent to a digital oscilloscope and are recorded. In the switching circuit, coaxial switches of SPDT (Single Pole Dual Throw) and SP4T type are used. To control coaxial switches, we adopted 'mbed', the ARM microcontroller development kit. The 'mbed' stores the control applications configured in the HTML file and JavaScript library which can handle multiple I/O ports. It responds as a HTTP server and the control application runs on a Web browser. By clicking buttons with a mouse, we can control the I/O ports of 'mbed' through JavaScript library and accordingly can control coaxial switches. In the presentation, we will report the detail of the developed BPM system and its performance.

MOPA34

Improvement of Hardware and Software Setup for the Acquisition and Processing of SIAM Photon Source BPM Signal

photon, PLC, feedback, software

130

N. Suradet, S. Boonsuya, S. Klinkhieo, P. Klysubun, S. Krainara, C.P. Preecha, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand

Data acquisition and processing system has been developed for the Siam Photon Source storage ring BPM system in order to improve monitoring and logging performances. BPM readout, i.e. scanning of BPM electrode voltage outputs and subsequently converting to X-Y position values, is now performed by an upgraded Programmable Logic Controller (PLC) with higher bit resolution (16-bit) analog-to-digital converter (ADC). Moving averaging is then performed on the obtained BPM data utilizing a LabVIEW code to reduce background noise during on-line measurement. All data is then stored on a dedicated computer serving as a central data logging system, which can be remotely accessed via a network communication link. In this report, details of the new setup will be presented, and comparison will be made between the performance of the new and previous setups, together with suggestions on further improvements.

MOPB52

Status and Activities of the SPring-8 Diagnostics Beamlines

photon, diagnostics, optics, emittance

186

S. Takano, M. Masaki, A. Mochihashi, H. Ohkuma, M. Shoji, K. Tamura
JASRI/SPring-8, Hyogo-ken, Japan
H. Sumitomo, M. Yoshioka
SES, Hyogo-pref., Japan

At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress.

MOPB56

Electron Cloud Measurements using a Time Resolved Retarding Field Analyzer at CesrTA

electron, detector, dipole, positron

201

J.P. Sikora, M.G. Billing, J.V. Conway, J.A. Crittenden, Y. Li, X. Liu, D. L. Rubin, C.R. Strohman
CLASSE, Ithaca, New York, USA
K. Kanazawa
KEK, Ibaraki, Japan
M.A. Palmer
Fermilab, Batavia, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, the US Department of Energy DE-FC02-08ER41538, DE-SC0006505 and US-Japan funding.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV. An area of research at CesrTA is the study of the growth, decay and mitigation of electron clouds in the storage ring. With a Retarding Field Analyzer (RFA), cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The electrons are captured by several collectors, so that the electron flux can be measured vs. horizontal position. Up to now, we have integrated the collector currents to provide DC measurements. We have recently constructed a new Time Resolved RFA, where the collector currents can be observed on the time scale of the bunch train in the storage ring. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements at CesrTA.

MOPB83

Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring

injection, synchrotron, timing, electron

276

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process.

MOPB86

Betatron Tune Measurement and Automatic Correction Systems at NewSUBARU Storage Ring

operation, betatron, survey, synchrotron

283

S. Hashimoto, Y. Hamada, S. Miyamoto
LASTI, Hyogo, Japan

At the 1.5GeV electron storage ring NewSUBARU, the two different kinds of systems for measuring betatron tunes have been developed: the high precision tune monitor and that for automatic correction. The vertical and horizontal tunes can be observed during the user time, because a stripe-line kicker to enlarge the beam lifetime vertically shakes electron beams. The high-precision tune monitor has the resolution of 0.0002 and uses frequency analysis methods such as SRSA, zoom FFT, STFT, in addition to usual FFT. Tune shifts due to a slight difference of filling patterns during top-up operations can be observed with this monitor. The another tune monitoring and automatic-correcting system has been developed to compensate tune shifts caused by the decrease of the stored current, the difference of filling patterns during top-up operations, and the energy ramp from 1.0 to 1.5 GeV. This system estimates betatron tunes every 0.5 sec and can keep tunes to the optimal values. The system also has a tune survey function that can automatically measure the beam lifetime in a tune diagram.

TUCC03

Design and Expected Performance of the New SLS Beam Size Monitor

emittance, polarization, synchrotron, synchrotron-radiation

307

N. Milas, M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun
PSI, Villigen PSI, Switzerland
Å. Andersson, J. Breunlin
MAX-lab, Lund, Sweden

The vertical emittance minimization campaign at SLS, realized in the context of the TIARA WP6, has already achieved the world's smallest vertical emittance of 0.9 pm in a synchrotron light source. The minimum value reached for the vertical emittance is only five times bigger than the quantum limit of 0.2 pm. However, the resolution limit of the present SLS emittance monitor has also been reached thus, to further continue the emittance minimization program the construction of an improved second monitor is necessary. In this paper we present the design and studies on the performance of this new monitor based on the image formation method using vertically polarized synchrotron radiation in the vis-UV spectral regimes. This monitor includes a new feature, providing the possibility of performing full interferometric measurement by the use of a set of vertical obstacles that can be driven on the light path. Simulations results are used to investigate the possible source of errors and their effects on imaging and the determination of the beam height. We also present the expected performance, in term of emittance accuracy and precision, and discuss possible design limitations.

Slides TUCC03 [8.497 MB]

TUPA01

Diagnostics Update of the Taiwan Photon Source

feedback, diagnostics, booster, synchrotron

324

C.H. Kuo, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.Y. Liao, C.Y. Wu
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a 3 GeV synchrotron light source which is being construction at campus of NSRRC. Various diagnostics are in implementation and will deploy in the future to satisfy stringent requirements of TPS for commissioning, top-up injection, and operation. These designs include beam intensity observation, trajectory and beam positions measurement, destructive profile measurement, synchrotron radiation monitors, beam loss monitors, orbit and bunch-by-bunch feedbacks, filling pattern and etc. are in final design phase. Progress of construction of the planned beam instrumentation system for the TPS will be summarized in this report.

TUPA05

The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System

pick-up, experiment, data-analysis, electron

334

Y.L. Yang, C. Cheng, P. Lu, T.J. Ma, B.G. Sun, J.G. Wang, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by National Natural Science Project(11105141) and Chinese Universities Scientific Fund
For bunch current measurement, the calibration factor is a key parameter. Usually, button electrode or stripline electrode can be selected as signal pickup, and peak value or integral of bunch signal from pickup can be used to calculate the related bunch current value. To obtain the absolute value of bunch current, the calibration factor should be determined with the help of DCCT. At HLS, the Stretch effect of bunch length was observed when bunch current decay over time and this will affect the performance of bunch current detection for different pickup type and calculate method. Theoretical analysis and experimental validation results are performed to find out an ideal solution for bunch current measurement at HLS. The results show that, bunch current measurement system can obtain the best performance by stripline and its integral signal.

TUPA07

BPM Selection for Beam Current Monitoring in SSRF

monitoring, operation, experiment, instrumentation

341

Z.C. Chen, Y.B. Leng, Y.B. Yan
SSRF, Shanghai, People's Republic of China

Although Direct Current Current Transformer (DCCT) is the general solution of beam current monitor, Beam Position Monitor (BPM) sum signals may still surpass it in some aspects such as the faster data rate and higher resolution in low current situations. Nevertheless, an additional monitor should be harmless. Meanwhile, the DCCTs in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been suffering from various noise and the signals from the BPMs could be an aid to provide the beam current more accurately. There're 140 BPMs in the storage ring in SSRF but not all of them are suitable for this particular usage. This article focuses on the methods used here to dynamicly choose the BPMs that meet the criteria.

TUPA10

Optical-Fiber Beam Loss Monitor for the KEK Photon Factory

injection, vacuum, electron, kicker

351

T. Obina, Y. Yano
KEK, Ibaraki, Japan

Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

TUPA33

Fast Orbit Feedback Calculation Implementation for TPS

brilliance, controls, feedback, FPGA

428

P. Leban, A. Bardorfer
I-Tech, Solkan, Slovenia
K.T. Hsu, C.H. Kuo
NSRRC, Hsinchu, Taiwan

Fast orbit feedback (FOFB) application is planned for the Taiwan Photon Source (TPS) at storage ring commissioning. Part of the application is transferred to the beam position electronics which implements global orbit position data concentration, its processing and actuating the magnet power supply controllers via optical links. The beam position electronics (Libera Brilliance+) includes gigabit data exchange (GDX) modules with Virtex6 field programmable gate array. The feedback calculation algorithm is based on the SVD ' the PI controller will be applied in the modal space for individual eigenmodes. The calculation will be distributed to all GDX modules to reduce overall latency. Each GDX module will calculate either 4 vertical or 4 horizontal magnet corrections. This article presents details about the FOFB topology and implementation in the GDX module.

TUPA35

Digital Longitudinal Bunch-by-bunch Feedback System for the HLS II

kicker, feedback, cavity, impedance

434

W.B. Li, P. Lu, B.G. Sun, F.F. Wu, W. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to suppress the longitudinal coupled bunch instabilities, a digital longitudinal bunch-by-bunch feedback system will be developed in the upgrade project of Hefei Light Source (HLS II). The longitudinal feedback system consists of a pickup BPM, a front-end signal processor unit to detect the phase errors of all electron bunches, an iGp signal processor to calculate correction signals of those bunches, two RF power amplifiers, and a longitudinal kicker to supply proper correction energy kicks to individual bunches. A new waveguide overloaded cavity longitudinal feedback kicker has been designed with broadband and high shunt impedance. In this paper, we describe an overview of the new longitudinal feedback system.

TUPA46

Streak Camera Measurements at ALBA: Bunch Length and Energy Matching

injection, booster, synchrotron, damping

458

U. Iriso, F.F.B. Fernández
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

This report describes the electron beam longitudinal studies performed at ALBA Storage Ring using the streak camera. We first show the usual studies involving precise bunch length measurements and related beam parameters like energy spread or momentum compaction factor. Next, the studies to match the injected beam in energy and phase are reported and compared with simulations.

TUPB49

Electron Cloud Density Measurements using Resonant TE Waves at CesrTA

resonance, electron, simulation, positron

471

J.P. Sikora, M.G. Billing, D.O. Duggins, Y. Li, D. L. Rubin, R.M. Schwartz, K.G. Sonnad
CLASSE, Ithaca, New York, USA
S. De Santis
LBNL, Berkeley, California, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam.

TUPB72

Injected Beam Profile Measurement during Top-up Operation

injection, operation, background, timing

508

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

A coronagraph-like apparatus was constructed on the optical diagnostic beamline on the storage ring to observe the injected beam during top-up operations. An image was created on an intensified CCD that can be gated on a single bunch or on a bunch train for a stronger signal. The bright central stored beam was obscured so the comparatively faint injected beam could be observed. The injected beam comes in at a large enough offset so that it was clearly visible above any diffraction or beam halo signals. The beam profile measured was in good agreement with the observations made of the injected beam only using a telescope apparatus. The measurements were made during user beam in top-up operation mode and can be used to optimise the injection process.

TUPB77

Measurement of the Frequency Spectrum on the Beam Profile Controlled by RF Kicker

radiation, betatron, detector, operation

524

Y. Yamamoto
Ritsumeikan University, Kusatsu-City, Shiga, Japan

The frequency spectrum on the beam profile was measured at the compact superconducting storage ring of Ritsumeikan University. The radiation detector was used an avalanche photodiode module with a high frequency response of 1 GHz for the visible ray. Signals from the detector were transferred to a spectrum analyzer. The beam profile was magnified strongly by a conventional profile monitor system. We scanned the beam profile in vertical direction by shifting the detector. The distribution of peak intensity as a function of the position on beam profile was obtained.

TUPB84

Storage Ring Tune Measurements using High-speed Metal-semiconductor-metal Photodetector

synchrotron, coupling, detector, electron

537

S. Dawson, D.J. Peake, R.P. Rassool
The University of Melbourne, Melbourne, Australia
M.J. Boland
ASCo, Clayton, Victoria, Australia
R.J. Steinhagen
CERN, Geneva, Switzerland

Knowledge of the betatron tunes within a storage ring is important to prevent the creation of instabilities and maximise the lifetime of the stored current within the ring. Typical tune measurements excite the beam and measure the resulting motion over time using electromagnetic pickups. The novel measurement technique presented utilises high-speed MSM photodiodes in a balanced detector set-up to measure the vertical and horizontal betatron tunes. Radiation from a bending magnet consists of both visible light and X-rays. The visible light is separated from the X-rays with an optical chicane and focussed onto a pair of length-matched optical fibers each coupled to an MSM photodiode. The specialised biasing circuit for the photodiodes is constructed in a balanced detector configuration to emphasise any motion in the beam. Signal resulting from beam motion is amplified and digitised for analysis. Using this set-up the tunes for the storage ring at the Australian Synchrotron have been measured and verified with comparison to existing tune measurement technologies. The results from the new optical tune measurement system will be presented and discussed.

TUPB85

Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm

injection, electron, wakefield, experiment

540

Y. Yang, Y.B. Leng
SSRF, Shanghai, People's Republic of China
B.P. Wang
SINAP, Shanghai, People's Republic of China

Based on the spectrum of turn-by-turn model for the storage ring, spectrum of multi-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve.

WECC03

Intensity Imbalance Optical Interferometer Beam Size Monitor

diagnostics, synchrotron, coupling, damping

566

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi, T. Naito
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

The technique of measuring the beam size in a particle accelerator with an optical interferometer with the Mitsuhashi apparatus is well established and one of the only direct measurement techniques available. However, one of the limitations of the technique is the dynamic range and noise level of CCD cameras when measuring ultra low emittance beams and hence visibilities close to unity. A new design has been successfully tested to overcome these limitations by introducing a know intensity imbalance in one of the light paths of the interferometer. This modification reduces the visibility in a controlled way and lifts the measured interference pattern out of the noise level of the CCD, thus increasing the dynamic range of the apparatus. Results are presented from tests at the ATF2 at KEK and on the optical diagnostic beamline at the Australian Synchrotron storage ring.

Slides WECC03 [2.383 MB]