IBIC2012 - List of Keywords (photon)

Paper	Title	Other Keywords	Page
MOCB04	Vertical Emittance Measurements using a Vertical Undulator	undulator, emittance, electron, brilliance	20
	K.P. Wootton, R.P. Rassool, G. Taylor The University of Melbourne, Melbourne, Australia M.J. Boland, B.C.C. Cowie, R.T. Dowd, Y.E. Tan ASCo, Clayton, Victoria, Australia Y. Papaphilippou CERN, Geneva, Switzerland
	With vertical dimensions of several microns, direct measurement of beam size is approaching diffraction limits of visible light and hard x-ray emittance diagnostics. We report on the development of a new vertical electron beam size measurement and monitoring technique which utilizes a vertical undulator. An APPLE-II type undulator was phased to produce a horizontal magnetic field, deflecting the electron beam in the vertical plane. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. Vertical electron beam emittances of several picometres have been observed at the Australian Synchrotron storage ring. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic.
	Slides MOCB04 [3.449 MB]

MOPA13	Real-time Calculation of Scale Factors of X-ray Beam Position Monitors during User Operation	electron, polarization, factory, insertion	79
	C. Bloomer, G. Rehm Diamond, Oxfordshire, United Kingdom
	Photoemission based X-ray Beam Position Monitors (XBPMs) are widely used at 3rd generation light sources to both monitor and stabilise the photon beam to sub-micron precision. Traditionally, finding the geometric scale factors requires either systematic stepper motor movements of the XBPM or well controlled electron beam displacements to measure the response of the XBPM. For each Insertion Device gap it is required to repeat this in order to build up a complete set of scale factors covering all possible operating conditions. Elliptically Polarising Undulators further complicate matters by having multiple operating modes which would require multi dimensional lookup tables. Presented in this paper is a method for retrieving the geometric scale factors of an XBPM in real time by making use of the intrinsic small random movements of the electron beam and finding the correlation in synchronous measurements from Electron BPMs and XBPMs at kHz sample rates.

MOPA21	Improvement of the SIAM Photon Source Storage Ring BPM System	storage-ring, shielding, 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.

MOPA24	Photon Beam Position Monitor at SIAM Photon Source	undulator, insertion, insertion-device, electron	104
	P. Sudmuang, S. Boonsuya, S. Chaichuay, P. Klysubun, S. Krainara, H. Nakajima, S. Rugmai, N. Sumano, N. Suradet SLRI, Nakhon Ratchasima, Thailand
	Photon beam position monitors (PBPM) have been designed and installed in the beamline front-ends at Siam Photon Source (SPS). Up till now, these blade-type PBPMs have been successfully installed at three bending magnet and an insertion device (planar undulator) beamlines. Its performance has been tested and compared with that of the electron beam position monitor. The achieved resolution is found to be better than 3 μm. The obtained PBPM data proved to be extremely invaluable in the investigation of the sources of the observed beam positional fluctuation, and for compensation of the orbit perturbation caused by undulator gap change. In this paper, the details of the calibration procedure will be presented. Various factors affecting reading of the signal such as back scattering effect, choice of bias voltage, and temperature variation have been investigated and the results will be discussed herewith.

MOPA34	Improvement of Hardware and Software Setup for the Acquisition and Processing of SIAM Photon Source BPM Signal	storage-ring, 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.

MOPA39	Introduction of Photon BPMs in SOLEIL Global Orbit Feedback Systems	feedback, dipole, operation, insertion	150
	N. Hubert, L. Cassinari, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	SOLEIL global orbit feedback systems (slow and fast), based on 122 electron Beam Position Monitor (e-BPM) readings, are in operation since 2008 and give very satisfying performances (0.1Hz-500Hz vertical noise below 300 nm RMS and long term (8h) drifts below 1μm RMS). Whereas each straight section is equipped with an upstream and downstream e-BPM, there is no e-BPM next to a dipole magnet. For that reason, photon BPMs (x-BPMs) in the dipole beamline frontends give additional information that can be used to better stabilize the source point in the dipoles. In fact x-BPMs provide also a better position angular measurement resolution, as they are located at 4 meters from the source point. Results presented in this paper show that vertical position stability on bending magnet beamlines can be improved by including their x-BPM measurements in the global orbit feedback systems. As a first step x-BPMs have been introduced in the Slow Orbit FeedBack system (SOFB) that corrects the orbit with a repetition rate of 0.1Hz. In a second step x-BPMs will be introduced in the Fast Orbit FeedBack system (FOFB) running at a repetition rate of 10 kHz.

MOPA48	Measurement of Temporal Resolution and Detection Efficiency of X-ray Streak Camera by Single Photon Images	timing, experiment, 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.

MOPB52	Status and Activities of the SPring-8 Diagnostics Beamlines	diagnostics, optics, storage-ring, 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.

MOPB88	Beam Size Monitor for TPS	electron, synchrotron, radiation, synchrotron-radiation	291
	C.K. Kuan, S.Y. Perng, I.C. Sheng, T.C. Tseng NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	The third-generation light source TPS is under construction in NSRRC. There are two diagnostic beamlines in the storage ring. Visible SR interferometers and X-ray pinhole cameras are widely used to measure the transverse beam profile in synchrotron light sources. In phase-I we will adopt the two methods to be the beam size monitor. The visible SR interferometer uses a double slit to obtain one-dimensional interference pattern along the horizontal or vertical axis. The simple X-ray pinhole camera is designed for the measurement of the size, the emittance and energy spread of the electron beam. In this paper we present the design and calculation of the two beam size monitors for TPS.

TUCC04	Measurement of Nanometer Electron Beam Sizes with Laser Interference using IPBSM	laser, optics, detector, alignment	310
	J.N. Yan, S. Komamiya, M. Oroku, T.S. Suehara, Y. Yamaguchi, T. Yamanaka University of Tokyo, Tokyo, Japan S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan Y. Kamiya ICEPP, Tokyo, Japan
	At ATF2, the Local Chromaticity Correction focusing scheme is to be verified through realizing its design vertical e^- beam size (σy ) of 37 nm. The 'IPBSM', installed at ATF2's virtual IP, is the only existing beam size monitor capable of measuring σy < 100 nm, making it indispensable for ATF's goals and R&D at future LCs. This owes to a novel technique of colliding e^- beam against laser interference fringes. σy is derived from the modulation depth of resulting Compton photons, which is large for small σy. The measurable range from O(10) nm ~ a few μm, is controlled by switching between laser crossing angles θ = 174° , 30°, and 2° - 8° . In early 2011, measuring σy < 300 nm was hindered by an immense earthquake and heavy signal jitters. The ensuing recovery and upgrades stabilized the laser system and improved resolution to 5%. In spring 2012, we commissioned advanced crossing angle modes by consistently measuring σy ≥ 150 nm. Our goals for the autumn 2012 run is to stably measure σy < 50 nm. Major hardware upgrades during the summer aim at more reliable alignment and optimization of specialized functions to suppress bias factors.
	Slides TUCC04 [10.535 MB]

TUPA41	Ultra-short Electron Bunch and X-ray Temporal Diagnostics with an X-band Transverse Deflecting Cavity	FEL, electron, undulator, klystron	441
	P. Krejcik, Y. Ding, J.C. Frisch, Z. Huang, H. Loos, J.W. Wang, M.-H. Wang SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany P. Emma LBNL, Berkeley, California, USA
	Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515 The technique of streaking an electron bunch with a RF deflecting cavity to measure its bunch length is being applied in a new way at the Linac Coherent Light Source with the goal of measuring the femtosecond temporal profile of the FEL photon beam. A powerful X-band deflecting cavity is being installed downstream of the FEL undulator and the streaked electron beam will be observed at an energy spectrometer screen at the beam dump. The single-shot measurements will reveal which time slices of the streaked beam have contributed to the FEL process by virtue of their greater energy loss and energy spread relative to the non-lasing portions of the electron bunch. Since the diagnostic is located downstream of the undulator it can be operated continuously without interrupting the beam to the users. The resolution of the new X-band system will be compared to the existing S-band RF deflecting diagnostic systems at SLAC and consideration is given to the required RF phase stability tolerances required for acceptable beam jitter on the monitor. Simulation studies show that about 1 fs (rms) time resolution is achievable in the LCLS over a wide range of FEL wavelengths and pulse lengths.

TUPB73	Development of a Beam Profile Monitor using Nitrogen-Molecular Jet for Intense Beams	electron, proton, target, ion	511
	Y. Hashimoto, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Fujisawa, T.M. Murakami, K. Noda NIRS, Chiba-shi, Japan Y. Hori, S. Muto, K. Yoshimura KEK, Ibaraki, Japan T. Morimoto Morimoto Engineering, Iruma, Saitama, Japan D. Ohsawa Kyoto University, Radioisotope Research Center, Kyoto-shi, Japan
	Funding: This work was supported by MEXT/JSPS KAKENHI Grant Number of 24310079 (Grant-in-Aid for Scientific Research(B)). A non-destructive beam profile monitor using a sheeted jet beam of nitrogen molecular as a target has been developed for intense ion beams. The pressure of the sheeted molecular beam was 5 x 10^-4 Pa at the beam collision point. A light emitted from excited nitrogen by an ion beam collision is measured by a high sensitive camera with a radiation resistant image intensifier. Verification of such a principle was already demonstrated with low-energy ion beams[1]. In this paper, some actual designs for intense beams of the J-PARC MR will be discussed mainly as bellow, intensity upgrade of the jet beam production, configuration of the detection chamber and its apparatus placed beam collision point, and the optical system for the light detection. *[1] Y. Hashimoto, et al., Proc. of IPAC'10, Kyoto, Japan, p.987-989.

WEIC02	Recent Progress in SR Interferometer	optics, experiment, 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

MOCB04

Vertical Emittance Measurements using a Vertical Undulator

undulator, emittance, electron, brilliance

20

K.P. Wootton, R.P. Rassool, G. Taylor
The University of Melbourne, Melbourne, Australia
M.J. Boland, B.C.C. Cowie, R.T. Dowd, Y.E. Tan
ASCo, Clayton, Victoria, Australia
Y. Papaphilippou
CERN, Geneva, Switzerland

With vertical dimensions of several microns, direct measurement of beam size is approaching diffraction limits of visible light and hard x-ray emittance diagnostics. We report on the development of a new vertical electron beam size measurement and monitoring technique which utilizes a vertical undulator. An APPLE-II type undulator was phased to produce a horizontal magnetic field, deflecting the electron beam in the vertical plane. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. Vertical electron beam emittances of several picometres have been observed at the Australian Synchrotron storage ring. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic.

Slides MOCB04 [3.449 MB]

MOPA13

Real-time Calculation of Scale Factors of X-ray Beam Position Monitors during User Operation

electron, polarization, factory, insertion

79

C. Bloomer, G. Rehm
Diamond, Oxfordshire, United Kingdom

Photoemission based X-ray Beam Position Monitors (XBPMs) are widely used at 3rd generation light sources to both monitor and stabilise the photon beam to sub-micron precision. Traditionally, finding the geometric scale factors requires either systematic stepper motor movements of the XBPM or well controlled electron beam displacements to measure the response of the XBPM. For each Insertion Device gap it is required to repeat this in order to build up a complete set of scale factors covering all possible operating conditions. Elliptically Polarising Undulators further complicate matters by having multiple operating modes which would require multi dimensional lookup tables. Presented in this paper is a method for retrieving the geometric scale factors of an XBPM in real time by making use of the intrinsic small random movements of the electron beam and finding the correlation in synchronous measurements from Electron BPMs and XBPMs at kHz sample rates.

MOPA21

Improvement of the SIAM Photon Source Storage Ring BPM System

storage-ring, shielding, 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.

MOPA24

Photon Beam Position Monitor at SIAM Photon Source

undulator, insertion, insertion-device, electron

104

P. Sudmuang, S. Boonsuya, S. Chaichuay, P. Klysubun, S. Krainara, H. Nakajima, S. Rugmai, N. Sumano, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

Photon beam position monitors (PBPM) have been designed and installed in the beamline front-ends at Siam Photon Source (SPS). Up till now, these blade-type PBPMs have been successfully installed at three bending magnet and an insertion device (planar undulator) beamlines. Its performance has been tested and compared with that of the electron beam position monitor. The achieved resolution is found to be better than 3 μm. The obtained PBPM data proved to be extremely invaluable in the investigation of the sources of the observed beam positional fluctuation, and for compensation of the orbit perturbation caused by undulator gap change. In this paper, the details of the calibration procedure will be presented. Various factors affecting reading of the signal such as back scattering effect, choice of bias voltage, and temperature variation have been investigated and the results will be discussed herewith.

MOPA34

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

storage-ring, 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.

MOPA39

Introduction of Photon BPMs in SOLEIL Global Orbit Feedback Systems

feedback, dipole, operation, insertion

150

N. Hubert, L. Cassinari, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

SOLEIL global orbit feedback systems (slow and fast), based on 122 electron Beam Position Monitor (e-BPM) readings, are in operation since 2008 and give very satisfying performances (0.1Hz-500Hz vertical noise below 300 nm RMS and long term (8h) drifts below 1μm RMS). Whereas each straight section is equipped with an upstream and downstream e-BPM, there is no e-BPM next to a dipole magnet. For that reason, photon BPMs (x-BPMs) in the dipole beamline frontends give additional information that can be used to better stabilize the source point in the dipoles. In fact x-BPMs provide also a better position angular measurement resolution, as they are located at 4 meters from the source point. Results presented in this paper show that vertical position stability on bending magnet beamlines can be improved by including their x-BPM measurements in the global orbit feedback systems. As a first step x-BPMs have been introduced in the Slow Orbit FeedBack system (SOFB) that corrects the orbit with a repetition rate of 0.1Hz. In a second step x-BPMs will be introduced in the Fast Orbit FeedBack system (FOFB) running at a repetition rate of 10 kHz.

MOPA48

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

timing, experiment, 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.

MOPB52

Status and Activities of the SPring-8 Diagnostics Beamlines

diagnostics, optics, storage-ring, 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.

MOPB88

Beam Size Monitor for TPS

electron, synchrotron, radiation, synchrotron-radiation

291

C.K. Kuan, S.Y. Perng, I.C. Sheng, T.C. Tseng
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

The third-generation light source TPS is under construction in NSRRC. There are two diagnostic beamlines in the storage ring. Visible SR interferometers and X-ray pinhole cameras are widely used to measure the transverse beam profile in synchrotron light sources. In phase-I we will adopt the two methods to be the beam size monitor. The visible SR interferometer uses a double slit to obtain one-dimensional interference pattern along the horizontal or vertical axis. The simple X-ray pinhole camera is designed for the measurement of the size, the emittance and energy spread of the electron beam. In this paper we present the design and calculation of the two beam size monitors for TPS.

TUCC04

Measurement of Nanometer Electron Beam Sizes with Laser Interference using IPBSM

laser, optics, detector, alignment

310

J.N. Yan, S. Komamiya, M. Oroku, T.S. Suehara, Y. Yamaguchi, T. Yamanaka
University of Tokyo, Tokyo, Japan
S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
Y. Kamiya
ICEPP, Tokyo, Japan

At ATF2, the Local Chromaticity Correction focusing scheme is to be verified through realizing its design vertical e^- beam size (σy ) of 37 nm. The 'IPBSM', installed at ATF2's virtual IP, is the only existing beam size monitor capable of measuring σy < 100 nm, making it indispensable for ATF's goals and R&D at future LCs. This owes to a novel technique of colliding e^- beam against laser interference fringes. σy is derived from the modulation depth of resulting Compton photons, which is large for small σy. The measurable range from O(10) nm ~ a few μm, is controlled by switching between laser crossing angles θ = 174° , 30°, and 2° - 8° . In early 2011, measuring σy < 300 nm was hindered by an immense earthquake and heavy signal jitters. The ensuing recovery and upgrades stabilized the laser system and improved resolution to 5%. In spring 2012, we commissioned advanced crossing angle modes by consistently measuring σy ≥ 150 nm. Our goals for the autumn 2012 run is to stably measure σy < 50 nm. Major hardware upgrades during the summer aim at more reliable alignment and optimization of specialized functions to suppress bias factors.

Slides TUCC04 [10.535 MB]

TUPA41

Ultra-short Electron Bunch and X-ray Temporal Diagnostics with an X-band Transverse Deflecting Cavity

FEL, electron, undulator, klystron

441

P. Krejcik, Y. Ding, J.C. Frisch, Z. Huang, H. Loos, J.W. Wang, M.-H. Wang
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany
P. Emma
LBNL, Berkeley, California, USA

Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515
The technique of streaking an electron bunch with a RF deflecting cavity to measure its bunch length is being applied in a new way at the Linac Coherent Light Source with the goal of measuring the femtosecond temporal profile of the FEL photon beam. A powerful X-band deflecting cavity is being installed downstream of the FEL undulator and the streaked electron beam will be observed at an energy spectrometer screen at the beam dump. The single-shot measurements will reveal which time slices of the streaked beam have contributed to the FEL process by virtue of their greater energy loss and energy spread relative to the non-lasing portions of the electron bunch. Since the diagnostic is located downstream of the undulator it can be operated continuously without interrupting the beam to the users. The resolution of the new X-band system will be compared to the existing S-band RF deflecting diagnostic systems at SLAC and consideration is given to the required RF phase stability tolerances required for acceptable beam jitter on the monitor. Simulation studies show that about 1 fs (rms) time resolution is achievable in the LCLS over a wide range of FEL wavelengths and pulse lengths.

TUPB73

Development of a Beam Profile Monitor using Nitrogen-Molecular Jet for Intense Beams

electron, proton, target, ion

511

Y. Hashimoto, T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Fujisawa, T.M. Murakami, K. Noda
NIRS, Chiba-shi, Japan
Y. Hori, S. Muto, K. Yoshimura
KEK, Ibaraki, Japan
T. Morimoto
Morimoto Engineering, Iruma, Saitama, Japan
D. Ohsawa
Kyoto University, Radioisotope Research Center, Kyoto-shi, Japan

Funding: This work was supported by MEXT/JSPS KAKENHI Grant Number of 24310079 (Grant-in-Aid for Scientific Research(B)).
A non-destructive beam profile monitor using a sheeted jet beam of nitrogen molecular as a target has been developed for intense ion beams. The pressure of the sheeted molecular beam was 5 x 10^-4 Pa at the beam collision point. A light emitted from excited nitrogen by an ion beam collision is measured by a high sensitive camera with a radiation resistant image intensifier. Verification of such a principle was already demonstrated with low-energy ion beams[1]. In this paper, some actual designs for intense beams of the J-PARC MR will be discussed mainly as bellow, intensity upgrade of the jet beam production, configuration of the detection chamber and its apparatus placed beam collision point, and the optical system for the light detection.
*[1] Y. Hashimoto, et al., Proc. of IPAC'10, Kyoto, Japan, p.987-989.

WEIC02

Recent Progress in SR Interferometer

optics, experiment, 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]