IPAC2011 - List of Authors (Maesaka, H.)

Paper

Title

Page

Commissioning and Performance of the Beam Monitor System for XFEL/SPring-8 “SACLA”

47

Y. Otake, C. Kondo, H. Maesaka
RIKEN Spring-8 Harima, Hyogo, Japan
H. Ego, S. Matsubara, T. Matsumoto, T. Sakurai, H. Tomizawa, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan
S.I. Inoue
SES, Hyogo-pref., Japan

The construction of a beam monitor system for XFEL/SPring 8 “SACLA” was completed. The system was developed to realize a spatial resolution of less than 3 um to align a beam orbit for an undulator section with about 100 m long and a temporal resolution to measure bunch lengths from 1 ns to 30 fs to maintain a constant peak beam current conducting stable SASE lasing. The system principally comprises cavity type beam position monitors (BPM), current monitors (CT), screen monitors (SCM) and bunch length measurement instruments, such as an rf deflector and CSR detectors. Commissioning of SACLA started from March 2011, and the monitors performed sufficient roles to tune beams for the lasing. The achieved over-all performances of the system including DAQ are: the BPM have spatial resolution of 300 nm, the bunch length monitors observe bunch lengths from 1ns in an injector with velocity bunching to less than 30 fs after three-stage bunch compressors. The less than a 3 um spatial resolution of the SCM was also confirmed in practical beam operation. By these fulfilled performances, the stable lasing of SACLA will be achieved. This report describes commissioning, performance of the system.

Slides MOOCB02 [7.516 MB]

TUPC092

Transverse C-band Deflecting Structure for Longitudinal Phase Space Diagnostics in the XFEL/SPring-8 “SACLA”

1221

H. Ego
RIKEN/SPring-8, Hyogo, Japan
T. Hashirano, S. Miura
MHI, Hiroshima, Japan
H. Maesaka, Y. Otake
RIKEN Spring-8 Harima, Hyogo, Japan
T. Sakurai
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

In SPring-8, the 8 GeV compact XFEL “SACLA” is under commissioning. A single bunch of electrons is compressed down to about 30 fs for brilliant SASE X-ray lasing. It is an important key of stable lasing to investigate the longitudinal phase space and the sliced emittance of a lasing part of the bunch by using a transverse RF deflector. We developed a high gradient C-band deflecting structure operated at 5712 MHz for the bunch diagnosis with a resolution of femtosecond regime at a limited space in the SACLA. The backward travelling-wave of the HEM11-5pi/6 mode is excited in the cylindrical structure periodically loaded with racetrack-shaped irises. The featuring irises suppress rotation of the deflection plane and generate strong cell-to-cell coupling for stable resonance. Two 1.8m-long structures were fabricated and installed in the SACLA. They successfully generated a deflection voltage over 40 MV and pitched the bunch at the zero-crossing RF phase. In this paper, we present the details of the fabrication and the deflecting performance of the structures applied to the diagnosis.

TUPC093

CSR Bunch Length Monitor for XFEL/SPring-8 - SACLA

1224

C. Kondo, S. Matsubara, T. Matsumoto
JASRI/SPring-8, Hyogo-ken, Japan
S.I. Inoue, H. Maesaka, Y. Otake
RIKEN Spring-8 Harima, Hyogo, Japan

SPring-8 Angstrom Compact Free Electron Laser (SACLA) is now under commissioning operation, aimed at the generation of a sub-angstrom free electron laser (FEL). In order to ensure the stable FEL generation, non-distractive bunch length monitors utilizing coherent synchrotron radiation (CSR) are installed. The monitors are located at the downstream of individual bunch compressor (BC1-BC3), and they measure the radiation emitted at the individual last magnets of the chicanes. At the magnets, beams with bunch lengths form 10 fs to 1000 fs generate the CSRs with a spectrum ranging the almost whole infrared region (0.03 - 3 THz). The CSRs are detected by a Schottky diode at the BC1, or pyroelectric detectors and a simple organic lens optical system at BC2 and 3. The bunch length monitor systems are used for bunch length feedback control to obtain the stable lasing by changing the rf parameter of acceleration cavities before the BCs. A preliminary system for the above mentioned system was tested at the SCSS test accelerator, and it showed sufficient performance to measure bunch length up to 300 fs. In this report, we describe the design and the results of the first operation.

TUPC094

Development of High-speed Differential Current-transformer Monitor

1227

S. Matsubara, H. Ego, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan
A. Higashiya, S.I. Inoue, Y. Otake
RIKEN/SPring-8, Hyogo, Japan
H. Maesaka
RIKEN Spring-8 Harima, Hyogo, Japan

The XFEL, which was named SACLA, was constructed in the SPring-8 site. In the SACLA, the bunch length of an electron beam is compressed from 1 ns to 30 fs, and the beam charge is decreased to obtain a genuine electron beam from 1nC to 0.3 nC for lasing. A new current-transformer (CT) monitor, which should measure the charge of the electron beam and make bunch length observation in velocity bunching process, was developed with two advantageous properties. One is differential output signal which suppresses common-mode noise from the thyratron of a klystron modulator by a factor of ten. Another property is high-speed signal output which provides a possibility to measure the bunch length and the time-of-flight (TOF) at the injector part of the SACLA. The output signal has 200 ps rise-time and a pulse width of 400 ps (FWHM) for an impulse beam. We successfully observed the bunch length between 1 ns and 400 ps around a 238 MHz buncher cavity. Moreover, we measured the TOF between two CTs with a few picoseconds resolution for a low-energy beam around 1 MeV. Thus, the new CT performance was confirmed to be sufficient for the SACLA.

TUPS085

Mass Production Report of C-band Choke Mode Accelerating Structure and RF Pulse Compressor

1737

S. Miura, T. Hashirano, F. Inoue, K. Okihira
MHI, Kobe, Japan
T. Inagaki
RIKEN/SPring-8, Hyogo, Japan
H. Maesaka, T. Shintake
RIKEN Spring-8 Harima, Hyogo, Japan

RIKEN and JASRI already completed the construction of XFEL/SPring8. Recently the facility was named “SACLA” (SPring-8 Angstrom Compact Free Electron LAser). The commissioning team succeeded in acceleration of 8 GeV electron beam and observation of the undulator light of 0.8 angstrom wavelength in March 2011. Now the accelerator is stably operated for the XFEL commissioning. In this project, a C-band (5712 MHz) choke mode accelerating structures and C-band RF pulse compressors are employed to obtain a high acceleration gradient of more than 35 MeV/m. We completed the fabrication of 128 accelerating structures, 64 RF pulse compressors, and 64 units of waveguide components and conducted RF measurements on them until May 2010. We report the result of the mass-production of these 64 C-Band units.

WEPC143

First Operation of the SACLA Control System in SPring-8

2325

R. Tanaka, Y. Furukawa, T. Hirono, M. Ishii, M. Kago, A. Kiyomichi, T. Masuda, T. Matsumoto, T. Matsushita, T. Ohata, C. Saji, T. Sugimoto, M. Yamaga, A. Yamashita
JASRI/SPring-8, Hyogo-ken, Japan
T. Fukui, T. Hatsui, N. Hosoda, T. Ohshima, T. Otake, Y. Otake, H. Takebe
RIKEN/SPring-8, Hyogo, Japan
H. Maesaka
RIKEN Spring-8 Harima, Hyogo, Japan

The control system design of the X-ray free electron laser facility (SACLA) in SPring-8 has started in 2006. Now, the facility has completed to start beam commissioning in February 2011. The electron beams were successfully accelerated up to 8 GeV and the first SASE X-ray was observed. The control system adopts the 3-tier standard model by using MADOCA framework developed in SPring-8. The upper control layer consists of Linux PCs for operator consoles, Sybase RDBMS for data logging and FC-based NAS for NFS. The lower layer consists of VMEbus systems with off-the-shelf I/O boards and specially developed boards for RF waveform processing with high precision. Solaris OS is adopted to operate VMEbus CPU. The PLC is used for slow control and connected to the VME systems via FL-net. The Device-net is adopted for frontend device control to reduce the number of signal cables. Some of VMEbus systems have a beam-synchronized data-taking system to meet 60Hz electron beam operation for the beam tuning diagnostics. The accelerator control system has gateways not only to monitor device status but also control the tuning points of the facility utility system, especially cooling water.

Paper	Title	Page
MOOCB02	Commissioning and Performance of the Beam Monitor System for XFEL/SPring-8 “SACLA”	47
	Y. Otake, C. Kondo, H. Maesaka RIKEN Spring-8 Harima, Hyogo, Japan H. Ego, S. Matsubara, T. Matsumoto, T. Sakurai, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan S.I. Inoue SES, Hyogo-pref., Japan
	The construction of a beam monitor system for XFEL/SPring 8 “SACLA” was completed. The system was developed to realize a spatial resolution of less than 3 um to align a beam orbit for an undulator section with about 100 m long and a temporal resolution to measure bunch lengths from 1 ns to 30 fs to maintain a constant peak beam current conducting stable SASE lasing. The system principally comprises cavity type beam position monitors (BPM), current monitors (CT), screen monitors (SCM) and bunch length measurement instruments, such as an rf deflector and CSR detectors. Commissioning of SACLA started from March 2011, and the monitors performed sufficient roles to tune beams for the lasing. The achieved over-all performances of the system including DAQ are: the BPM have spatial resolution of 300 nm, the bunch length monitors observe bunch lengths from 1ns in an injector with velocity bunching to less than 30 fs after three-stage bunch compressors. The less than a 3 um spatial resolution of the SCM was also confirmed in practical beam operation. By these fulfilled performances, the stable lasing of SACLA will be achieved. This report describes commissioning, performance of the system.
	Slides MOOCB02 [7.516 MB]

TUPC092	Transverse C-band Deflecting Structure for Longitudinal Phase Space Diagnostics in the XFEL/SPring-8 “SACLA”	1221
	H. Ego RIKEN/SPring-8, Hyogo, Japan T. Hashirano, S. Miura MHI, Hiroshima, Japan H. Maesaka, Y. Otake RIKEN Spring-8 Harima, Hyogo, Japan T. Sakurai RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	In SPring-8, the 8 GeV compact XFEL “SACLA” is under commissioning. A single bunch of electrons is compressed down to about 30 fs for brilliant SASE X-ray lasing. It is an important key of stable lasing to investigate the longitudinal phase space and the sliced emittance of a lasing part of the bunch by using a transverse RF deflector. We developed a high gradient C-band deflecting structure operated at 5712 MHz for the bunch diagnosis with a resolution of femtosecond regime at a limited space in the SACLA. The backward travelling-wave of the HEM11-5pi/6 mode is excited in the cylindrical structure periodically loaded with racetrack-shaped irises. The featuring irises suppress rotation of the deflection plane and generate strong cell-to-cell coupling for stable resonance. Two 1.8m-long structures were fabricated and installed in the SACLA. They successfully generated a deflection voltage over 40 MV and pitched the bunch at the zero-crossing RF phase. In this paper, we present the details of the fabrication and the deflecting performance of the structures applied to the diagnosis.

TUPC093	CSR Bunch Length Monitor for XFEL/SPring-8 - SACLA	1224
	C. Kondo, S. Matsubara, T. Matsumoto JASRI/SPring-8, Hyogo-ken, Japan S.I. Inoue, H. Maesaka, Y. Otake RIKEN Spring-8 Harima, Hyogo, Japan
	SPring-8 Angstrom Compact Free Electron Laser (SACLA) is now under commissioning operation, aimed at the generation of a sub-angstrom free electron laser (FEL). In order to ensure the stable FEL generation, non-distractive bunch length monitors utilizing coherent synchrotron radiation (CSR) are installed. The monitors are located at the downstream of individual bunch compressor (BC1-BC3), and they measure the radiation emitted at the individual last magnets of the chicanes. At the magnets, beams with bunch lengths form 10 fs to 1000 fs generate the CSRs with a spectrum ranging the almost whole infrared region (0.03 - 3 THz). The CSRs are detected by a Schottky diode at the BC1, or pyroelectric detectors and a simple organic lens optical system at BC2 and 3. The bunch length monitor systems are used for bunch length feedback control to obtain the stable lasing by changing the rf parameter of acceleration cavities before the BCs. A preliminary system for the above mentioned system was tested at the SCSS test accelerator, and it showed sufficient performance to measure bunch length up to 300 fs. In this report, we describe the design and the results of the first operation.

TUPC094	Development of High-speed Differential Current-transformer Monitor	1227
	S. Matsubara, H. Ego, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan A. Higashiya, S.I. Inoue, Y. Otake RIKEN/SPring-8, Hyogo, Japan H. Maesaka RIKEN Spring-8 Harima, Hyogo, Japan
	The XFEL, which was named SACLA, was constructed in the SPring-8 site. In the SACLA, the bunch length of an electron beam is compressed from 1 ns to 30 fs, and the beam charge is decreased to obtain a genuine electron beam from 1nC to 0.3 nC for lasing. A new current-transformer (CT) monitor, which should measure the charge of the electron beam and make bunch length observation in velocity bunching process, was developed with two advantageous properties. One is differential output signal which suppresses common-mode noise from the thyratron of a klystron modulator by a factor of ten. Another property is high-speed signal output which provides a possibility to measure the bunch length and the time-of-flight (TOF) at the injector part of the SACLA. The output signal has 200 ps rise-time and a pulse width of 400 ps (FWHM) for an impulse beam. We successfully observed the bunch length between 1 ns and 400 ps around a 238 MHz buncher cavity. Moreover, we measured the TOF between two CTs with a few picoseconds resolution for a low-energy beam around 1 MeV. Thus, the new CT performance was confirmed to be sufficient for the SACLA.

TUPS085	Mass Production Report of C-band Choke Mode Accelerating Structure and RF Pulse Compressor	1737
	S. Miura, T. Hashirano, F. Inoue, K. Okihira MHI, Kobe, Japan T. Inagaki RIKEN/SPring-8, Hyogo, Japan H. Maesaka, T. Shintake RIKEN Spring-8 Harima, Hyogo, Japan
	RIKEN and JASRI already completed the construction of XFEL/SPring8. Recently the facility was named “SACLA” (SPring-8 Angstrom Compact Free Electron LAser). The commissioning team succeeded in acceleration of 8 GeV electron beam and observation of the undulator light of 0.8 angstrom wavelength in March 2011. Now the accelerator is stably operated for the XFEL commissioning. In this project, a C-band (5712 MHz) choke mode accelerating structures and C-band RF pulse compressors are employed to obtain a high acceleration gradient of more than 35 MeV/m. We completed the fabrication of 128 accelerating structures, 64 RF pulse compressors, and 64 units of waveguide components and conducted RF measurements on them until May 2010. We report the result of the mass-production of these 64 C-Band units.

WEPC143	First Operation of the SACLA Control System in SPring-8	2325
	R. Tanaka, Y. Furukawa, T. Hirono, M. Ishii, M. Kago, A. Kiyomichi, T. Masuda, T. Matsumoto, T. Matsushita, T. Ohata, C. Saji, T. Sugimoto, M. Yamaga, A. Yamashita JASRI/SPring-8, Hyogo-ken, Japan T. Fukui, T. Hatsui, N. Hosoda, T. Ohshima, T. Otake, Y. Otake, H. Takebe RIKEN/SPring-8, Hyogo, Japan H. Maesaka RIKEN Spring-8 Harima, Hyogo, Japan
	The control system design of the X-ray free electron laser facility (SACLA) in SPring-8 has started in 2006. Now, the facility has completed to start beam commissioning in February 2011. The electron beams were successfully accelerated up to 8 GeV and the first SASE X-ray was observed. The control system adopts the 3-tier standard model by using MADOCA framework developed in SPring-8. The upper control layer consists of Linux PCs for operator consoles, Sybase RDBMS for data logging and FC-based NAS for NFS. The lower layer consists of VMEbus systems with off-the-shelf I/O boards and specially developed boards for RF waveform processing with high precision. Solaris OS is adopted to operate VMEbus CPU. The PLC is used for slow control and connected to the VME systems via FL-net. The Device-net is adopted for frontend device control to reduce the number of signal cables. Some of VMEbus systems have a beam-synchronized data-taking system to meet 60Hz electron beam operation for the beam tuning diagnostics. The accelerator control system has gateways not only to monitor device status but also control the tuning points of the facility utility system, especially cooling water.