IBIC2014 - List of Keywords (photon)

Paper	Title	Other Keywords	Page
MOPF03	NSLSII Photon Beam Position Monitor ElectronicsTesting and Results	electronics, detector, controls, software	42
	A.J. Della Penna, M.A. Maggipinto, J. Mead, O. Singh, K. Vetter BNL, Upton, Long Island, New York, USA
	Simulated and real beam data has been taken using the new NSLSII Photon BPM electronics. The electrometer design can measure currents as low as 10’s of nanoamps and has an ability to measure a current as high as 300mA. The 4 channel design allows for internal calibration and has both a Negative and Positive bias ability. Preliminary bench testing results has shown excellent resolution.
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MOPF10	A Compact In-Air X-Ray Detector for Vertical Beam Size Measurement at ALBA	electron, dipole, detector, storage-ring	69
	A.A. Nosych, U. Iriso ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	An in-air x-ray detector (IXD) was developed for ALBA to study the residual x-rays after traversing the 35mm copper crotch absorbers. The device prototype is placed in-air after such absorber, mounted flush with the vacuum pipe. The remaining x-rays (above 120 keV) generate a visible footprint if they impinge upon a sensitive enough scintillator. We are using a Cerium doped PreLude 420 (LuYSiO:Ce) screen, and the image is observed with a simple optics system mounted on a commercial CCD camera. This measurement allows evaluating the vertical electron beam size with exposure times in the order of seconds. Similar instruments are used at ESRF and ANKA storage rings. This paper presents the results of the first measurements with IXD and describes its potential to be used as a full diagnostics tool for the 3 GeV storage ring of ALBA.
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MOPF17	Methods for Measuring the Transverse Beam Profile in the ESS High Intensity Beam	linac, proton, ion, space-charge	93
	C. Roose, I. Dolenc Kittelmann, A. Jansson ESS, Lund, Sweden
	The European Spallation Source (ESS), currently under construction, consists of a partly superconducting linac which will deliver a 2 GeV, 5MW proton beam to a rotating tungsten target. Beam transverse profile monitors are required in order to insure that the lattice parameters are set and the beam emittance is matched. Due to the high intensity of the beam and the constraint to perform non-disturbing measurements, non-invasive techniques have to be developed. The non-invasive profile monitors chosen for the ESS are based on the interaction of the beam with the residual gas. Two different devices are developed, one utilises the fluorescence process, the other one the ionisation process. The paper presents their latest preliminary developments.
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MOPD11	Near-Saturation Single-Photon Avalanche Diode Afterpulse and Sensitivity Correction Scheme for the LHC Longitudinal Density Monitor	detector, laser, synchrotron-radiation, synchrotron	169
	M. Palm, E. Bravin, S. Mazzoni CERN, Geneva, Switzerland
	Funding: CERN Single-Photon Avalanche Diodes (SPADs) monitor the longitudinal density of the LHC beams by measuring the temporal distribution of synchrotron radiation. The relative population of nominally empty RF-buckets (satellites or ghosts) with respect to filled bunches is a key figure for the luminosity calibration of the LHC experiments. Since afterpulsing from a main bunch avalanche can be as high as, or higher than, the signal from satellites or ghosts, an accurate correction algorithm is needed. Furthermore, to reduce the integration time, the amount of light sent to the SPAD is enough so that pile-up effects and afterpulsing cannot be neglected. The SPAD sensitivity has also been found to vary at the end of the active quenching phase. We present a method to characterize and correct for SPAD deadtime, afterpulsing and sensitivity variation near saturation, together with laboratory benchmarking.
	Poster MOPD11 [6.756 MB]
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MOPD21	Bunch Pattern Measurement via Single Photon Counting at SPEAR3	timing, injection, controls, storage-ring	195
	W.J. Corbett, W.Y. Mok, K. Tian SLAC, Menlo Park, California, USA
	SPEAR3 is a 3GeV storage ring x-ray source that provides up to 500mA circulating beam current in top-up mode. Charge injection occurs on a 5 minute time schedule with the booster synchrotron delivering on-demand single-bunch pulses at 10Hz. In recent years the synchrotron radiation user program has moved in the direction of laser/x-ray pump-probe experiments which utilize a single timing ‘probe’ bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in adjacent buckets, a time-correlated single-photon counting system has been tested. By monitoring the bunch pattern, is it possible to evaluate when the x-ray probe bunch is sufficiently isolated, and pave the way for shot-by-shot charge injection that maintains all bunches at specified current levels.
	Poster MOPD21 [3.375 MB]
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MOPD26	A Bunch Extension Monitor for the Spiral2 LINAC	linac, ion, detector, diagnostics	212
	J.L. Vignet, R.V. Revenko GANIL, Caen, France
	Measurements of the longitudinal shape of bunched beam particles are crucial for optimization and control of LINAC beam parameters and maximization of its integrated luminosity. The non-interceptive bunch extension monitor for the LINAC at the SPIRAL2 facility is being developed at GANIL. Five bunch extension monitors will be installed at the beginning of the LINAC between superconducting cavities. The principle of operation is based on the registration of x-rays induced by ions of accelerator beam interacting with a thin tungsten wire positioned on the beam path. The monitor consists of two parts: a system for wire insertion and positioning, and an x-ray detector based on microchannel plates (MCPs). A detector prototype has been developed over the past three years and was tested using both protons and heavy ions beams.
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TUCYB1	Study of scintillation stability in KBr, YAG:Ce, CaF2:Eu and CsI:Tl Irradiated by Various-Energy Protons	ion, radiation, target, emittance	250
	L.Y. Lin FRIB, East Lansing, Michigan, USA
	The luminescence of KBr, YAG:Ce, CaF2:Eu and CsI:Tl scintillators induced with H²⁺ ion beams in the energy range of 600-2150 keV/u has been systematically measured as a function of irradiation time. The measurements showed that the luminescence of CsI:Tl and YAG:Ce remained constant within the 1-hour continuous irradiation. An initial fast drop of the luminescence on CaF2:Eu was observed but the light output eventually approached a stable state under constant ion bombardment. We also observed that the light output of KBr initially increased and then degraded gradually with further irradiation. The CsI:Tl screen produced the highest scintillation yield and KBr the lowest.
	Slides TUCYB1 [2.078 MB]
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TUIZB1	Radiation Sources and Their Application for Beam Profile Diagnostics	radiation, diagnostics, electron, optics	263
	G. Kube DESY, Hamburg, Germany
	Radiation generated by high-energy particle beams is widely used for beam diagnostic purposes. Depending on the mechanism of radiation generation, the emitted wavelength range extends from the THz up to the X-ray region, thus allowing the measurement of beam profiles in the longitudinal and the transverse plane over a wide range. In this talk, basic considerations for radiation based profile measurements will be discussed with special emphasis on the mechanism of radiation generation and the impact on beam diagnostic measurements.
	Slides TUIZB1 [4.803 MB]
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TUCZB3	A Quantum Gas Jet for Non-Invasive Beam Profile Measurement	ion, focusing, electron, vacuum	284
	A. Jeff, E.B. Holzer, T. Lefèvre CERN, Geneva, Switzerland A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom V. Tzoganis, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom
	A novel instrument for accelerator beam diagnostics is being developed by using De Broglie-wave focusing to create an ultra-thin neutral gas jet. Scanning the gas jet across a particle beam while measuring the interaction products, the beam profile can be measured. Such a jet scanner will provide an invaluable diagnostic tool in beams which are too intense for the use of wire scanners, such as the proposed CLIC Drive Beam. In order to create a sufficiently thin jet, a focusing element working on the DeBroglie wavelength of the Helium atom has been designed. Following the principles of the Photon Sieve, we have constructed an Atomic Sieve consisting of 5230 nano-holes etched into a thin film of silicon nitride. When a quasi-monochromatic Helium jet is incident on the sieve, an interference pattern with a single central maximum is created. The stream of Helium atoms passing through this central maximum is much narrower than a conventional gas jet. The first experiences with this device are presented here, along with plans for further tests.
	Slides TUCZB3 [13.880 MB]
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TUPF13	Diamond-Based Photon BPMs for Fast Electron-Beam Diagnostics in Synchrotron Radiation Sources	electron, radiation, diagnostics, detector	342
	M. Antonelli, G. Cautero, D. Giuressi, S. Lizzit, R.H. Menk Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy A. De Sio, E. Pace Università degli Studi di Firenze, Firenze, Italy M. Di Fraia Università degli Studi di Trieste, Trieste, Italy
	Electron-beam stability is amongst the primary concerns in current Synchrotron Radiation (SR) sources; in particular, in third-generation SR facilities high-brightness beamlines using undulator radiation are extremely sensitive to electron-beam oscillations. Orbit stabilization has been intensively addressed in the past years and many SR machines have been equipped with a Fast Orbit Feedback (FOFB) based on electron Beam-Position Monitors (eBPMs). On the other hand, photon Beam-Position Monitors (pBPMs), besides providing beamline users with crucial calibration data, are also a useful tool for keeping the electron beam under control, by monitoring position and intensity of the delivered radiation. The machine control system can take advantage of this information in order to improve the stability of the electron-beam. A diagnostic beamline, utilizing a couple of fast pBPMs based on single-crystal CVD diamond detectors, has been built and inserted into the central dead-end outlet of one of Elettra’s bending-magnets. Tests have been carried out both during normal machine operations and by deliberately moving the orbit during dedicated shifts. Owing to the outstanding properties of diamond in terms of speed and radiation hardness, the results show how the aforementioned system allows the beam position to be monitored with sub-micrometric precision at the demanding readout rates required by the FOFB. The radiation hardness of the sensors allows the operation over extended periods of time without special maintenance. Therefore, this system is particularly suited for storage-ring sections lacking in electron-beam monitoring and the tested diagnostic line represents a demonstrator for future implementation of pBPMs at several bending-magnet front ends of Elettra.
	Poster TUPF13 [3.409 MB]
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TUPF26	Linear Focal Cherenkov-Ring Camera for Single Shot Observation of Longitudinal Phase Space Distribution for Non-Relativistic Electron Beam	electron, vacuum, laser, gun	385
	K. Nanbu, H. Hama, F. Hinode, S. Kashiwagi, A. Lueangaramwong, T. Muto, I. Nagasawa, S. Nagasawa, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A test accelerator for the coherent THz source (t-ACTS) has been constructed at Tohoku University, in which the generation of intense coherent THz radiation from sub-picosecond electron bunches will be demonstrated. The final electron bunch length of accelerated beam is mostly dictated by the longitudinal phase space distribution at the exit of electron-gun. Therefore, measurement of Initial electron distribution in the longitudinal phase space produced by an electron gun is crucial for stable production of very short electron bunches, However, measurement of the longitudinal phase space of a relatively lower energy electron beam is especially difficult because space charge effects in drift spaces for measurement system might be strong. A method for measurement of electron energy (or momentum) applying velocity dependence of the opening angle of Cherenkov radiation in the radiator has been proposed for relatively lower energy electrons. Combined use of a streak camera and the “turtle-back” mirror that confines the Cherenkov light onto a linear focal line may allow us to observe the longitudinal phase space distribution directly. Current status of the system development will be reported in this conference.
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WEPF21	Electron Cloud Density Measurements Using Resonant Microwaves at CesrTA	resonance, electron, positron, storage-ring	592
	J.P. Sikora Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, 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. Hardware has recently been installed in the Cornell Electron Storage Ring (CESR) to extend the capability of resonant microwave measurement of electron cloud density. Two new detector locations include aluminum beam-pipe in a dipole magnet and copper beam-pipe in a field free region. Measurements with both positron and electron beams are presented with both beams showing saturation of the electron cloud density in the aluminum chamber. These measurements were made at CESR which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.
	Poster WEPF21 [1.988 MB]
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WEPF25	A Fast Quadrupole Magnet for Machine Studies at Diamond	quadrupole, simulation, resonance, storage-ring	605
	A.F.D. Morgan, G. Rehm DLS, Oxfordshire, United Kingdom
	Fast quadrupolar magnets have been demonstrated in various schemes for increasing the coupled bunch instability thresholds, and for measuring the shift of transverse quadrupolar moment oscillation thus probing the transverse quadrupolar impedance. Due to machine upgrades, a ceramic vessel installed in the Diamond storage ring has become temporarily available for use. We decided to take advantage of this situation by designing and installing a simple air core quadrupole magnet which can operate at the fundamental quadrupolar frequencies (~212kHz for the horizontal and ~405kHz for the vertical plane). In the first instance we aim to use it to study the coupled bunch instability thresholds and quadrupolar tune shifts.
	Poster WEPF25 [1.359 MB]
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WEPD22	Design of a New Blade-Type XBPM	synchrotron, insertion, insertion-device, undulator	687
	N. Hubert, N. Béchu, L. Cassinari, J. Da Silva Castro, J.-C. Denard, M. Labat, J.L. Marlats, A. Mary SOLEIL, Gif-sur-Yvette, France S.R. Marques, R.T. Neuenschwander LNLS, Campinas, Brazil
	A new photon Beam Position Monitor (X-BPM) design has been developed in collaboration between the Brazilian Synchrotron Light Laboratory (LNLS) and SOLEIL Synchrotron. This blade-type X-BPM has been carefully studied in order to minimize beam current dependence and temperature dependence. The main advantages of the design are a good stability than the standard X-BPMs initially installed at SOLEIL. This new design is used for the new X-BPMs installed at SOLEIL and is being considered for the bending magnet front-ends of the future SIRIUS light source. A first “double” unit has been constructed by LNLS for the two canted Anatomix and Nanoscopium SOLEIL beamlines, and has been installed at SOLEIL in May 2014. Design and first results are presented.
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THCXB1	Cross-Calibration of Three Electron Cloud Density Detectors at CesrTA	electron, simulation, detector, resonance	722
	J.P. Sikora, J.R. Calvey, J.A. Crittenden Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, 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. Measurements of electron cloud density using three detector types are compared under the same beam conditions at the same location in the Cornell Electron Storage Ring (CESR). Two of the detectors sample the flux of cloud electrons incident on the beam-pipe wall. The Retarding Field Analyzer (RFA) records the time-averaged charge flux and has a retarding grid that can be biased to select high energy electrons. The Shielded Button Electrode (SBE) samples the electron flux without a retarding grid, acquiring signals with sub-nanosecond resolution. The third detector uses resonant microwaves and measures the electron cloud density within the beam-pipe through the cloud-induced shift in resonant frequency. The analysis will include comparison of the output from POSINST and ECLOUD simulations of electron cloud buildup. These time-sliced particle-in-cell 2D modeling codes – simulating photoelectron production, secondary emission and cloud dynamics – have been expanded to include the electron acceptance of the RFA and SBE detectors in order to model the measured signals. The measurements were made at the CESR storage ring, which has been reconfigured as a test accelerator (CesrTA) providing electron or positron beams ranging in energy from 2 GeV to 5 GeV.
	Slides THCXB1 [3.240 MB]
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Paper

Title

Other Keywords

Page

MOPF03

NSLSII Photon Beam Position Monitor ElectronicsTesting and Results

electronics, detector, controls, software

42

A.J. Della Penna, M.A. Maggipinto, J. Mead, O. Singh, K. Vetter
BNL, Upton, Long Island, New York, USA

Simulated and real beam data has been taken using the new NSLSII Photon BPM electronics. The electrometer design can measure currents as low as 10’s of nanoamps and has an ability to measure a current as high as 300mA. The 4 channel design allows for internal calibration and has both a Negative and Positive bias ability. Preliminary bench testing results has shown excellent resolution.

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MOPF10

A Compact In-Air X-Ray Detector for Vertical Beam Size Measurement at ALBA

electron, dipole, detector, storage-ring

69

A.A. Nosych, U. Iriso
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

An in-air x-ray detector (IXD) was developed for ALBA to study the residual x-rays after traversing the 35mm copper crotch absorbers. The device prototype is placed in-air after such absorber, mounted flush with the vacuum pipe. The remaining x-rays (above 120 keV) generate a visible footprint if they impinge upon a sensitive enough scintillator. We are using a Cerium doped PreLude 420 (LuYSiO:Ce) screen, and the image is observed with a simple optics system mounted on a commercial CCD camera. This measurement allows evaluating the vertical electron beam size with exposure times in the order of seconds. Similar instruments are used at ESRF and ANKA storage rings. This paper presents the results of the first measurements with IXD and describes its potential to be used as a full diagnostics tool for the 3 GeV storage ring of ALBA.

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MOPF17

Methods for Measuring the Transverse Beam Profile in the ESS High Intensity Beam

linac, proton, ion, space-charge

93

C. Roose, I. Dolenc Kittelmann, A. Jansson
ESS, Lund, Sweden

The European Spallation Source (ESS), currently under construction, consists of a partly superconducting linac which will deliver a 2 GeV, 5MW proton beam to a rotating tungsten target. Beam transverse profile monitors are required in order to insure that the lattice parameters are set and the beam emittance is matched. Due to the high intensity of the beam and the constraint to perform non-disturbing measurements, non-invasive techniques have to be developed. The non-invasive profile monitors chosen for the ESS are based on the interaction of the beam with the residual gas. Two different devices are developed, one utilises the fluorescence process, the other one the ionisation process. The paper presents their latest preliminary developments.

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MOPD11

Near-Saturation Single-Photon Avalanche Diode Afterpulse and Sensitivity Correction Scheme for the LHC Longitudinal Density Monitor

detector, laser, synchrotron-radiation, synchrotron

169

M. Palm, E. Bravin, S. Mazzoni
CERN, Geneva, Switzerland

Funding: CERN
Single-Photon Avalanche Diodes (SPADs) monitor the longitudinal density of the LHC beams by measuring the temporal distribution of synchrotron radiation. The relative population of nominally empty RF-buckets (satellites or ghosts) with respect to filled bunches is a key figure for the luminosity calibration of the LHC experiments. Since afterpulsing from a main bunch avalanche can be as high as, or higher than, the signal from satellites or ghosts, an accurate correction algorithm is needed. Furthermore, to reduce the integration time, the amount of light sent to the SPAD is enough so that pile-up effects and afterpulsing cannot be neglected. The SPAD sensitivity has also been found to vary at the end of the active quenching phase. We present a method to characterize and correct for SPAD deadtime, afterpulsing and sensitivity variation near saturation, together with laboratory benchmarking.

Poster MOPD11 [6.756 MB]

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MOPD21

Bunch Pattern Measurement via Single Photon Counting at SPEAR3

timing, injection, controls, storage-ring

195

W.J. Corbett, W.Y. Mok, K. Tian
SLAC, Menlo Park, California, USA

SPEAR3 is a 3GeV storage ring x-ray source that provides up to 500mA circulating beam current in top-up mode. Charge injection occurs on a 5 minute time schedule with the booster synchrotron delivering on-demand single-bunch pulses at 10Hz. In recent years the synchrotron radiation user program has moved in the direction of laser/x-ray pump-probe experiments which utilize a single timing ‘probe’ bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in adjacent buckets, a time-correlated single-photon counting system has been tested. By monitoring the bunch pattern, is it possible to evaluate when the x-ray probe bunch is sufficiently isolated, and pave the way for shot-by-shot charge injection that maintains all bunches at specified current levels.

Poster MOPD21 [3.375 MB]

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MOPD26

A Bunch Extension Monitor for the Spiral2 LINAC

linac, ion, detector, diagnostics

212

J.L. Vignet, R.V. Revenko
GANIL, Caen, France

Measurements of the longitudinal shape of bunched beam particles are crucial for optimization and control of LINAC beam parameters and maximization of its integrated luminosity. The non-interceptive bunch extension monitor for the LINAC at the SPIRAL2 facility is being developed at GANIL. Five bunch extension monitors will be installed at the beginning of the LINAC between superconducting cavities. The principle of operation is based on the registration of x-rays induced by ions of accelerator beam interacting with a thin tungsten wire positioned on the beam path. The monitor consists of two parts: a system for wire insertion and positioning, and an x-ray detector based on microchannel plates (MCPs). A detector prototype has been developed over the past three years and was tested using both protons and heavy ions beams.

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TUCYB1

Study of scintillation stability in KBr, YAG:Ce, CaF2:Eu and CsI:Tl Irradiated by Various-Energy Protons

ion, radiation, target, emittance

250

L.Y. Lin
FRIB, East Lansing, Michigan, USA

The luminescence of KBr, YAG:Ce, CaF2:Eu and CsI:Tl scintillators induced with H²⁺ ion beams in the energy range of 600-2150 keV/u has been systematically measured as a function of irradiation time. The measurements showed that the luminescence of CsI:Tl and YAG:Ce remained constant within the 1-hour continuous irradiation. An initial fast drop of the luminescence on CaF2:Eu was observed but the light output eventually approached a stable state under constant ion bombardment. We also observed that the light output of KBr initially increased and then degraded gradually with further irradiation. The CsI:Tl screen produced the highest scintillation yield and KBr the lowest.

Slides TUCYB1 [2.078 MB]

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TUIZB1

Radiation Sources and Their Application for Beam Profile Diagnostics

radiation, diagnostics, electron, optics

263

G. Kube
DESY, Hamburg, Germany

Radiation generated by high-energy particle beams is widely used for beam diagnostic purposes. Depending on the mechanism of radiation generation, the emitted wavelength range extends from the THz up to the X-ray region, thus allowing the measurement of beam profiles in the longitudinal and the transverse plane over a wide range. In this talk, basic considerations for radiation based profile measurements will be discussed with special emphasis on the mechanism of radiation generation and the impact on beam diagnostic measurements.

Slides TUIZB1 [4.803 MB]

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TUCZB3

A Quantum Gas Jet for Non-Invasive Beam Profile Measurement

ion, focusing, electron, vacuum

284

A. Jeff, E.B. Holzer, T. Lefèvre
CERN, Geneva, Switzerland
A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
V. Tzoganis, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

A novel instrument for accelerator beam diagnostics is being developed by using De Broglie-wave focusing to create an ultra-thin neutral gas jet. Scanning the gas jet across a particle beam while measuring the interaction products, the beam profile can be measured. Such a jet scanner will provide an invaluable diagnostic tool in beams which are too intense for the use of wire scanners, such as the proposed CLIC Drive Beam. In order to create a sufficiently thin jet, a focusing element working on the DeBroglie wavelength of the Helium atom has been designed. Following the principles of the Photon Sieve, we have constructed an Atomic Sieve consisting of 5230 nano-holes etched into a thin film of silicon nitride. When a quasi-monochromatic Helium jet is incident on the sieve, an interference pattern with a single central maximum is created. The stream of Helium atoms passing through this central maximum is much narrower than a conventional gas jet. The first experiences with this device are presented here, along with plans for further tests.

Slides TUCZB3 [13.880 MB]

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TUPF13

Diamond-Based Photon BPMs for Fast Electron-Beam Diagnostics in Synchrotron Radiation Sources

electron, radiation, diagnostics, detector

342

M. Antonelli, G. Cautero, D. Giuressi, S. Lizzit, R.H. Menk
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. De Sio, E. Pace
Università degli Studi di Firenze, Firenze, Italy
M. Di Fraia
Università degli Studi di Trieste, Trieste, Italy

Electron-beam stability is amongst the primary concerns in current Synchrotron Radiation (SR) sources; in particular, in third-generation SR facilities high-brightness beamlines using undulator radiation are extremely sensitive to electron-beam oscillations. Orbit stabilization has been intensively addressed in the past years and many SR machines have been equipped with a Fast Orbit Feedback (FOFB) based on electron Beam-Position Monitors (eBPMs). On the other hand, photon Beam-Position Monitors (pBPMs), besides providing beamline users with crucial calibration data, are also a useful tool for keeping the electron beam under control, by monitoring position and intensity of the delivered radiation. The machine control system can take advantage of this information in order to improve the stability of the electron-beam. A diagnostic beamline, utilizing a couple of fast pBPMs based on single-crystal CVD diamond detectors, has been built and inserted into the central dead-end outlet of one of Elettra’s bending-magnets. Tests have been carried out both during normal machine operations and by deliberately moving the orbit during dedicated shifts. Owing to the outstanding properties of diamond in terms of speed and radiation hardness, the results show how the aforementioned system allows the beam position to be monitored with sub-micrometric precision at the demanding readout rates required by the FOFB. The radiation hardness of the sensors allows the operation over extended periods of time without special maintenance. Therefore, this system is particularly suited for storage-ring sections lacking in electron-beam monitoring and the tested diagnostic line represents a demonstrator for future implementation of pBPMs at several bending-magnet front ends of Elettra.

Poster TUPF13 [3.409 MB]

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TUPF26

Linear Focal Cherenkov-Ring Camera for Single Shot Observation of Longitudinal Phase Space Distribution for Non-Relativistic Electron Beam

electron, vacuum, laser, gun

385

K. Nanbu, H. Hama, F. Hinode, S. Kashiwagi, A. Lueangaramwong, T. Muto, I. Nagasawa, S. Nagasawa, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test accelerator for the coherent THz source (t-ACTS) has been constructed at Tohoku University, in which the generation of intense coherent THz radiation from sub-picosecond electron bunches will be demonstrated. The final electron bunch length of accelerated beam is mostly dictated by the longitudinal phase space distribution at the exit of electron-gun. Therefore, measurement of Initial electron distribution in the longitudinal phase space produced by an electron gun is crucial for stable production of very short electron bunches, However, measurement of the longitudinal phase space of a relatively lower energy electron beam is especially difficult because space charge effects in drift spaces for measurement system might be strong. A method for measurement of electron energy (or momentum) applying velocity dependence of the opening angle of Cherenkov radiation in the radiator has been proposed for relatively lower energy electrons. Combined use of a streak camera and the “turtle-back” mirror that confines the Cherenkov light onto a linear focal line may allow us to observe the longitudinal phase space distribution directly. Current status of the system development will be reported in this conference.

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WEPF21

Electron Cloud Density Measurements Using Resonant Microwaves at CesrTA

resonance, electron, positron, storage-ring

592

J.P. Sikora
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, 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.
Hardware has recently been installed in the Cornell Electron Storage Ring (CESR) to extend the capability of resonant microwave measurement of electron cloud density. Two new detector locations include aluminum beam-pipe in a dipole magnet and copper beam-pipe in a field free region. Measurements with both positron and electron beams are presented with both beams showing saturation of the electron cloud density in the aluminum chamber. These measurements were made at CESR which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.

Poster WEPF21 [1.988 MB]

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WEPF25

A Fast Quadrupole Magnet for Machine Studies at Diamond

quadrupole, simulation, resonance, storage-ring

605

A.F.D. Morgan, G. Rehm
DLS, Oxfordshire, United Kingdom

Fast quadrupolar magnets have been demonstrated in various schemes for increasing the coupled bunch instability thresholds, and for measuring the shift of transverse quadrupolar moment oscillation thus probing the transverse quadrupolar impedance. Due to machine upgrades, a ceramic vessel installed in the Diamond storage ring has become temporarily available for use. We decided to take advantage of this situation by designing and installing a simple air core quadrupole magnet which can operate at the fundamental quadrupolar frequencies (~212kHz for the horizontal and ~405kHz for the vertical plane). In the first instance we aim to use it to study the coupled bunch instability thresholds and quadrupolar tune shifts.

Poster WEPF25 [1.359 MB]

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WEPD22

Design of a New Blade-Type XBPM

synchrotron, insertion, insertion-device, undulator

687

N. Hubert, N. Béchu, L. Cassinari, J. Da Silva Castro, J.-C. Denard, M. Labat, J.L. Marlats, A. Mary
SOLEIL, Gif-sur-Yvette, France
S.R. Marques, R.T. Neuenschwander
LNLS, Campinas, Brazil

A new photon Beam Position Monitor (X-BPM) design has been developed in collaboration between the Brazilian Synchrotron Light Laboratory (LNLS) and SOLEIL Synchrotron. This blade-type X-BPM has been carefully studied in order to minimize beam current dependence and temperature dependence. The main advantages of the design are a good stability than the standard X-BPMs initially installed at SOLEIL. This new design is used for the new X-BPMs installed at SOLEIL and is being considered for the bending magnet front-ends of the future SIRIUS light source. A first “double” unit has been constructed by LNLS for the two canted Anatomix and Nanoscopium SOLEIL beamlines, and has been installed at SOLEIL in May 2014. Design and first results are presented.

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THCXB1

Cross-Calibration of Three Electron Cloud Density Detectors at CesrTA

electron, simulation, detector, resonance

722

J.P. Sikora, J.R. Calvey, J.A. Crittenden
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, 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.
Measurements of electron cloud density using three detector types are compared under the same beam conditions at the same location in the Cornell Electron Storage Ring (CESR). Two of the detectors sample the flux of cloud electrons incident on the beam-pipe wall. The Retarding Field Analyzer (RFA) records the time-averaged charge flux and has a retarding grid that can be biased to select high energy electrons. The Shielded Button Electrode (SBE) samples the electron flux without a retarding grid, acquiring signals with sub-nanosecond resolution. The third detector uses resonant microwaves and measures the electron cloud density within the beam-pipe through the cloud-induced shift in resonant frequency. The analysis will include comparison of the output from POSINST and ECLOUD simulations of electron cloud buildup. These time-sliced particle-in-cell 2D modeling codes – simulating photoelectron production, secondary emission and cloud dynamics – have been expanded to include the electron acceptance of the RFA and SBE detectors in order to model the measured signals. The measurements were made at the CESR storage ring, which has been reconfigured as a test accelerator (CesrTA) providing electron or positron beams ranging in energy from 2 GeV to 5 GeV.

Slides THCXB1 [3.240 MB]

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