IBIC2012 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOCC01	UV/X-ray Diffraction Radiation for Non-intercepting Micron-scale Beam Size Measurement	target, radiation, electron, background	24
	L.M. Bobb, N. Chritin, T. Lefèvre CERN, Geneva, Switzerland M.G. Billing CLASSE, Ithaca, New York, USA L.M. Bobb, V. Karataev JAI, Egham, Surrey, United Kingdom
	Diffraction Radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. Therefore DR can be used to develop non-invasive diagnostic tools. The aim of this project is to measure the transverse (vertical) beam size using incoherent DR. To achieve the micron-scale resolution required by CLIC, DR in the UV and X-ray spectral-range must be investigated. During the next few years, experimental validation of such a scheme will be conducted on the CesrTA at Cornell University, USA. Here we present the current status of the experiment preparation.
	Slides MOCC01 [3.064 MB]

MOPA04	An Electron Beam Profile Monitor for the Race-track Microtron	electron, controls, microtron, operation	54
	S.D. Dhole, V.N. Bhoraskar, B.J. Patil, N.S. Shinde University of Pune, Pune, India
	In electron irradiation experiments on materials such as semiconductors, solar cells etc., an uniformity and the charge distribution in the electron beam is very important. Therefore, an electron beam current monitor and its electronic system have been designed and built to measure the distribution of a beam current either in the horizontal or vertical direction along with the beam dimensions. To obtain X-Y beam profile, a special type of Faraday Cup was designed which mainly consists of charge collecting electrodes made up of thin copper strips. Each strip having dimensions 0.5 mm wide, 4 mm thick and 20 mm long were fixed parallel to each other and separation between them was ~ 0.5 mm. This multi electrode Faraday was mounted at the extraction port of the Race Track Microtron, where 1 MeV electron beam allowed to fall on it. The beam characterization in the form of current and uniformity were measured. The current from each strip were measured using an electronic circuit developed based on the multiplexing principle. The uniformity of the beam can be measured with an accuracy of 10%. The minimum and maximum dimensions which can be measured are 3 mm and 15 mm respectively.

MOPA42	Measurements of Martin-Puplett Interferometer Limitations using Blackbody Source	detector, radiation, FEL, vacuum	153
	P.E. Evtushenko, J.M. Klopf JLAB, Newport News, Virginia, USA
	Frequency domain measurements with Martin-Puplett interferometer is one of a few techniques capable of bunch length measurements at the level of ~ 100 fs. As the bunch length becomes shorter, it is important to know and be able to measure the limitations of the instrument in terms of shortest measurable bunch length. In this paper we describe experiment of using blackbody source with the modified Matrin-Puplett interferometer that is routinely used for bunch length measurements at the JLab FEL, as a way to estimate the shortest, measurable with the device, bunch. The limitation comes from high frequency cut-off of the presently used wire-grid polarizer and is estimated to be 50 fs RMS. The measurements are made with the same Golay cell detector that is used for beam measurements. We demonstrate that, even though the blackbody source is many orders of magnitude less bright than the coherent transition or synchrotron radiation, it can be used for the measurements and gives a very good signal to noise ratio in a combination with lock-in detection. We also compare the measurements made in air and in vacuum to show the very strong effect of the atmospheric absorption.

MOPA48	Measurement of Temporal Resolution and Detection Efficiency of X-ray Streak Camera by Single Photon Images	photon, timing, electron, cathode	171
	A. Mochihashi, M. Masaki, H. Ohkuma, S. Takano, K. Tamura JASRI/SPring-8, Hyogo-ken, Japan
	Funding: This work was partly supported by MEXT Grant-in-Aid for Young Scientists (B) Grant number 21740215. In the third generation and the next generation synchrotron radiation light sources, the electron beam bunch length of ps ~ sub-ps is expected to be achieved. An X-ray streak camera (X-SC) can directly measure the temporal width of X-ray synchrotron radiation pulse. The temporal resolution of X-SC depends on the initial velocity distribution of the photoelectrons from a photocathode which converts the X-ray photons to the photoelectrons. To measure the temporal resolution of the X-SC, we have observed 'single photon' streak camera images and measured the temporal spread of the images. By this 'single photon' experiment, we have evaluated the dependence of the temporal resolution and the detection efficiency on the photon energy. We have also tried to evaluate the dependence of the temporal resolution and the detection efficiency on the thickness of the photocathode. For this purpose, we have developed a multi-array type CsI photocathode with 3 different thickness of the photocathode. The experimental setups, and the results of the measurements of the temporal spread and the detection efficiency of the single photon events will be presented.

MOPB85	Latest Results from the 4.8GHz LHC Schottky Systems	proton, ion, injection, pick-up	279
	M. Favier, O.R. Jones CERN, Geneva, Switzerland
	This paper will present the latest results from the LHC 4.8GHz travelling wave Schottky system, summarising measurements performed during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies.

TUIC02	Direct Observation of the Dust-trapping Phenomenon	vacuum, electron, ion, high-voltage	315
	Y. Tanimoto KEK, Ibaraki, Japan
	Dust trapping has long been an unwelcome and mysterious phenomenon in electron storage rings. As it leads to a sudden decrease in beam lifetime, dust trapping has been a perpetual nuisance at the Photon Factory Advanced Ring (PF-AR) since its beginning in the 1980s. However, during recent research on dust trapping at the PF-AR, video cameras serendipitously captured the culprit behind this phenomenon; the cameras recorded a luminous micro-particle trapped in the electron beam, just as if a shooting star were traveling in the beam tube. In the successive research, supersensitive cameras repeatedly observed trapped dust particles, and revealed that they behaved differently under different conditions. My presentation will summarize these experimental results, as well as long-term statistics supporting present dust-trapping theories.
	Slides TUIC02 [8.200 MB]

TUPA05	The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System	pick-up, storage-ring, 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.

TUPA06	Pulsed Electron Beam Current and Flux Monitor for the Race-track Microtron	electron, induction, microtron, controls	337
	S.D. Dhole, S. Akhter, V.N. Bhoraskar, B.J. Patil, N.S. Shinde University of Pune, Pune, India
	In electron irradiation experiments on the materials, a true current of the electron beam is to be known to calculate the electron fluence received by the sample. Therefore, a pulsed electron beam current and flux monitor alongwith electronic system for an electron accelerator called Race-Track Microtron has been designed and developed. The sensing device used was a ferrite core having suitable number of turns of copper wire wound around it, through which the electron beam was passed without loss in the intensity. With an appropriate developed electronic circuit, the instantaneous value of the induced voltage was measured which in turn provides value of the electron beam pulsed current. The total charge passed through the ferrite core per unit time was therefore recorded and an integrated value of the total charge in a given period could be derived. This system can be used to measure the electron flux in the range from 10⁸ electron/cm² to 10¹⁶ electron/cm². Moreover, this system has been used successfully in a few electron irradiation experiments where the knowledge of the electron fluence received by the sample is required.

TUPA07	BPM Selection for Beam Current Monitoring in SSRF	storage-ring, monitoring, operation, 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.

TUPA08	Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC	luminosity, vacuum, data-acquisition, background	344
	M.E. Castro Carballo DESY Zeuthen, Zeuthen, Germany
	The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA12	A DBPM Calibration Method Implemented on FPGA	FPGA, controls, operation, linac	358
	X.D. Sun, Y.B. Leng SINAP, Shanghai, People's Republic of China
	An calibration method on the four channels of DBPM is discussed . Using interpolation, the method is implemented on FPGA , which can handle the data on-line. The calibration algorithm is mono-channel dependent and is intended to solve the beam current dependence problem and increase resolution. Orientations of the method is presented. Basic design diagrams of the pipelined FPGA modules are listed and comparisons are made before and after the calibration

TUPA44	Status of the LCLS Experiment Timing System	timing, laser, electron, feedback	453
	J.C. Frisch, C. Bostedt, R.N. Coffee, A.R. Fry, N. Hartmann, J. May, D.J. Nicholson, S. Schorb, S.R. Smith SLAC, Menlo Park, California, USA
	Funding: Work Supported by Department of Energy Contract DE AC03 76SF00515 X-ray / optical laser pump - probe experiments are used for a significant fraction of the scientific work performed at LCLS. The experimental laser systems are locked to the timing of the electron beam through a combination of RF and optical fiber based systems. The remaining ~100 femtosecond RMS jitter of the X-rays relative to the optical laser is measured shot-to-shot by both a RF timing detector, and by direct X-ray to optical cross-correlation, and the result is used to correct the experiment timing to 10s of femtoseconds. We present the present status of the system and plans for future upgrades.

TUPB79	Use of Gafchromic Films to Measure the Transverse Intensity Distribution of a Large-area Ion Beam	ion, multipole, cyclotron, background	531
	Y. Yuri, I. Ishibori, T. Ishizaka, A. Kitamura, S. Okumura, T. Yuyama JAEA/TARRI, Gunma-ken, Japan S. Sawada, T. Yamaki JAEA/QuBS, Takasaki, Japan
	In the TIARA AVF cyclotron facility of JAEA, it is necessary to evaluate the cross-sectional area and uniformity of a large-area uniform ion beam formed by multipole magnets both precisely and handily. A technique has, therefore, been developed to measure the two-dimensional transverse intensity distribution of the ion beam using Gafchromic radiochromic films (Ashland Inc.). In order to show available fluence ranges of the film, the coloring response of the Gafchromic films irradiated with several species of ion beams is investigated as a change in the optical density of the film. It has been found that the optical density increases linearly with the fluence, whose range is practical for materials and biological research. Thus, the relative transverse intensity distribution of ion beams can be measured using the film. Furthermore, the intensity distribution determined by the Gafchromic film is compared with the area-density distribution of track-etched pores in a polymer film from a microscopic viewpoint. It has been demonstrated that the beam uniformity obtained from the Gafchromic film is equivalent to the relative standard deviation of the microscopic pore distribution.

TUPB85	Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm	storage-ring, injection, electron, wakefield	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.

WEIC02	Recent Progress in SR Interferometer	photon, optics, factory, detector	576
	T.M. Mitsuhashi KEK, Ibaraki, Japan
	Beam size measurement in accelerator is very important to evaluate beam emittance.　SR interferometer has been used as one of powerful tools for measurement of small beam size through special coherence of visible SR. Recent progresses in this technique improve measurable range for smaller beam size less than 10μm. An application of reflective optics to eliminate chromatic aberration in focus system of SR interferometer makes it possible to measure the beam size down to 5μm range. The unbalanced input technique is developed in recent few years, and this technique magnifies beam size 2-3 times, and observation range is improved down to 2-3μm range. These progresses on SR interferometer will introduce in this talk.
	Slides WEIC02 [1.687 MB]

Paper

Title

Other Keywords

Page

MOCC01

UV/X-ray Diffraction Radiation for Non-intercepting Micron-scale Beam Size Measurement

target, radiation, electron, background

24

L.M. Bobb, N. Chritin, T. Lefèvre
CERN, Geneva, Switzerland
M.G. Billing
CLASSE, Ithaca, New York, USA
L.M. Bobb, V. Karataev
JAI, Egham, Surrey, United Kingdom

Diffraction Radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. Therefore DR can be used to develop non-invasive diagnostic tools. The aim of this project is to measure the transverse (vertical) beam size using incoherent DR. To achieve the micron-scale resolution required by CLIC, DR in the UV and X-ray spectral-range must be investigated. During the next few years, experimental validation of such a scheme will be conducted on the CesrTA at Cornell University, USA. Here we present the current status of the experiment preparation.

Slides MOCC01 [3.064 MB]

MOPA04

An Electron Beam Profile Monitor for the Race-track Microtron

electron, controls, microtron, operation

54

S.D. Dhole, V.N. Bhoraskar, B.J. Patil, N.S. Shinde
University of Pune, Pune, India

In electron irradiation experiments on materials such as semiconductors, solar cells etc., an uniformity and the charge distribution in the electron beam is very important. Therefore, an electron beam current monitor and its electronic system have been designed and built to measure the distribution of a beam current either in the horizontal or vertical direction along with the beam dimensions. To obtain X-Y beam profile, a special type of Faraday Cup was designed which mainly consists of charge collecting electrodes made up of thin copper strips. Each strip having dimensions 0.5 mm wide, 4 mm thick and 20 mm long were fixed parallel to each other and separation between them was ~ 0.5 mm. This multi electrode Faraday was mounted at the extraction port of the Race Track Microtron, where 1 MeV electron beam allowed to fall on it. The beam characterization in the form of current and uniformity were measured. The current from each strip were measured using an electronic circuit developed based on the multiplexing principle. The uniformity of the beam can be measured with an accuracy of 10%. The minimum and maximum dimensions which can be measured are 3 mm and 15 mm respectively.

MOPA42

Measurements of Martin-Puplett Interferometer Limitations using Blackbody Source

detector, radiation, FEL, vacuum

153

P.E. Evtushenko, J.M. Klopf
JLAB, Newport News, Virginia, USA

Frequency domain measurements with Martin-Puplett interferometer is one of a few techniques capable of bunch length measurements at the level of ~ 100 fs. As the bunch length becomes shorter, it is important to know and be able to measure the limitations of the instrument in terms of shortest measurable bunch length. In this paper we describe experiment of using blackbody source with the modified Matrin-Puplett interferometer that is routinely used for bunch length measurements at the JLab FEL, as a way to estimate the shortest, measurable with the device, bunch. The limitation comes from high frequency cut-off of the presently used wire-grid polarizer and is estimated to be 50 fs RMS. The measurements are made with the same Golay cell detector that is used for beam measurements. We demonstrate that, even though the blackbody source is many orders of magnitude less bright than the coherent transition or synchrotron radiation, it can be used for the measurements and gives a very good signal to noise ratio in a combination with lock-in detection. We also compare the measurements made in air and in vacuum to show the very strong effect of the atmospheric absorption.

MOPA48

Measurement of Temporal Resolution and Detection Efficiency of X-ray Streak Camera by Single Photon Images

photon, timing, electron, cathode

171

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

Funding: This work was partly supported by MEXT Grant-in-Aid for Young Scientists (B) Grant number 21740215.
In the third generation and the next generation synchrotron radiation light sources, the electron beam bunch length of ps ~ sub-ps is expected to be achieved. An X-ray streak camera (X-SC) can directly measure the temporal width of X-ray synchrotron radiation pulse. The temporal resolution of X-SC depends on the initial velocity distribution of the photoelectrons from a photocathode which converts the X-ray photons to the photoelectrons. To measure the temporal resolution of the X-SC, we have observed 'single photon' streak camera images and measured the temporal spread of the images. By this 'single photon' experiment, we have evaluated the dependence of the temporal resolution and the detection efficiency on the photon energy. We have also tried to evaluate the dependence of the temporal resolution and the detection efficiency on the thickness of the photocathode. For this purpose, we have developed a multi-array type CsI photocathode with 3 different thickness of the photocathode. The experimental setups, and the results of the measurements of the temporal spread and the detection efficiency of the single photon events will be presented.

MOPB85

Latest Results from the 4.8GHz LHC Schottky Systems

proton, ion, injection, pick-up

279

M. Favier, O.R. Jones
CERN, Geneva, Switzerland

This paper will present the latest results from the LHC 4.8GHz travelling wave Schottky system, summarising measurements performed during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies.

TUIC02

Direct Observation of the Dust-trapping Phenomenon

vacuum, electron, ion, high-voltage

315

Y. Tanimoto
KEK, Ibaraki, Japan

Dust trapping has long been an unwelcome and mysterious phenomenon in electron storage rings. As it leads to a sudden decrease in beam lifetime, dust trapping has been a perpetual nuisance at the Photon Factory Advanced Ring (PF-AR) since its beginning in the 1980s. However, during recent research on dust trapping at the PF-AR, video cameras serendipitously captured the culprit behind this phenomenon; the cameras recorded a luminous micro-particle trapped in the electron beam, just as if a shooting star were traveling in the beam tube. In the successive research, supersensitive cameras repeatedly observed trapped dust particles, and revealed that they behaved differently under different conditions. My presentation will summarize these experimental results, as well as long-term statistics supporting present dust-trapping theories.

Slides TUIC02 [8.200 MB]

TUPA05

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

pick-up, storage-ring, 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.

TUPA06

Pulsed Electron Beam Current and Flux Monitor for the Race-track Microtron

electron, induction, microtron, controls

337

S.D. Dhole, S. Akhter, V.N. Bhoraskar, B.J. Patil, N.S. Shinde
University of Pune, Pune, India

In electron irradiation experiments on the materials, a true current of the electron beam is to be known to calculate the electron fluence received by the sample. Therefore, a pulsed electron beam current and flux monitor alongwith electronic system for an electron accelerator called Race-Track Microtron has been designed and developed. The sensing device used was a ferrite core having suitable number of turns of copper wire wound around it, through which the electron beam was passed without loss in the intensity. With an appropriate developed electronic circuit, the instantaneous value of the induced voltage was measured which in turn provides value of the electron beam pulsed current. The total charge passed through the ferrite core per unit time was therefore recorded and an integrated value of the total charge in a given period could be derived. This system can be used to measure the electron flux in the range from 10⁸ electron/cm² to 10¹⁶ electron/cm². Moreover, this system has been used successfully in a few electron irradiation experiments where the knowledge of the electron fluence received by the sample is required.

TUPA07

BPM Selection for Beam Current Monitoring in SSRF

storage-ring, monitoring, operation, 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.

TUPA08

Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC

luminosity, vacuum, data-acquisition, background

344

M.E. Castro Carballo
DESY Zeuthen, Zeuthen, Germany

The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA12

A DBPM Calibration Method Implemented on FPGA

FPGA, controls, operation, linac

358

X.D. Sun, Y.B. Leng
SINAP, Shanghai, People's Republic of China

An calibration method on the four channels of DBPM is discussed . Using interpolation, the method is implemented on FPGA , which can handle the data on-line. The calibration algorithm is mono-channel dependent and is intended to solve the beam current dependence problem and increase resolution. Orientations of the method is presented. Basic design diagrams of the pipelined FPGA modules are listed and comparisons are made before and after the calibration

TUPA44

Status of the LCLS Experiment Timing System

timing, laser, electron, feedback

453

J.C. Frisch, C. Bostedt, R.N. Coffee, A.R. Fry, N. Hartmann, J. May, D.J. Nicholson, S. Schorb, S.R. Smith
SLAC, Menlo Park, California, USA

Funding: Work Supported by Department of Energy Contract DE AC03 76SF00515
X-ray / optical laser pump - probe experiments are used for a significant fraction of the scientific work performed at LCLS. The experimental laser systems are locked to the timing of the electron beam through a combination of RF and optical fiber based systems. The remaining ~100 femtosecond RMS jitter of the X-rays relative to the optical laser is measured shot-to-shot by both a RF timing detector, and by direct X-ray to optical cross-correlation, and the result is used to correct the experiment timing to 10s of femtoseconds. We present the present status of the system and plans for future upgrades.

TUPB79

Use of Gafchromic Films to Measure the Transverse Intensity Distribution of a Large-area Ion Beam

ion, multipole, cyclotron, background

531

Y. Yuri, I. Ishibori, T. Ishizaka, A. Kitamura, S. Okumura, T. Yuyama
JAEA/TARRI, Gunma-ken, Japan
S. Sawada, T. Yamaki
JAEA/QuBS, Takasaki, Japan

In the TIARA AVF cyclotron facility of JAEA, it is necessary to evaluate the cross-sectional area and uniformity of a large-area uniform ion beam formed by multipole magnets both precisely and handily. A technique has, therefore, been developed to measure the two-dimensional transverse intensity distribution of the ion beam using Gafchromic radiochromic films (Ashland Inc.). In order to show available fluence ranges of the film, the coloring response of the Gafchromic films irradiated with several species of ion beams is investigated as a change in the optical density of the film. It has been found that the optical density increases linearly with the fluence, whose range is practical for materials and biological research. Thus, the relative transverse intensity distribution of ion beams can be measured using the film. Furthermore, the intensity distribution determined by the Gafchromic film is compared with the area-density distribution of track-etched pores in a polymer film from a microscopic viewpoint. It has been demonstrated that the beam uniformity obtained from the Gafchromic film is equivalent to the relative standard deviation of the microscopic pore distribution.

TUPB85

Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm

storage-ring, injection, electron, wakefield

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.

WEIC02

Recent Progress in SR Interferometer

photon, optics, factory, detector

576

T.M. Mitsuhashi
KEK, Ibaraki, Japan

Beam size measurement in accelerator is very important to evaluate beam emittance.　SR interferometer has been used as one of powerful tools for measurement of small beam size through special coherence of visible SR. Recent progresses in this technique improve measurable range for smaller beam size less than 10μm. An application of reflective optics to eliminate chromatic aberration in focus system of SR interferometer makes it possible to measure the beam size down to 5μm range. The unbalanced input technique is developed in recent few years, and this technique magnifies beam size 2-3 times, and observation range is improved down to 2-3μm range. These progresses on SR interferometer will introduce in this talk.

Slides WEIC02 [1.687 MB]