BL19LXU

◆Outline of beamline

BL19LXU is equipped with a 27-m-long undulator as the brightest X-ray source. The optics hutch contains a Si (111) double-crystal monochromator with cryogenic cooling and a double mirror with the SPring-8 standard mechanism. EH3 is an open hutch, where users can bring in their own apparatus. We will welcome researches in any field, just requiring the highly brilliant X-ray beam.

◆Research field

This beamline is open for any research field requiring the highly brilliant X-ray beam

◆Light source and optical system

EH3
The EH3, where public users can set up their instrumentation, has a comparably large size of 5 (W) × 3.4 (D) × 4.5 (H) m3, and is located at about 77 m distant from the undulator source. The room temperature in the hutch can precisely be controlled by an air conditioner. A manually operated chain hoist could help to install apparatus in the hutch.

EH1, 2, and 4
Although these experimental hutches (EH1, 2, and 4) are occupied by equipments of high precision goniometers, an intense laser system, and a superconducting magnet for the RIKEN project, small components are still able to be mounted in the hutches by public users. (As for the hutch size and the distance from source, see schematic view of beamline.)

Available equipments for public users are listed bellow:
・Optical bench
・APD, PIN photodiode, Scintillation counter, Ionization chamber
・Stepping motor drivers and controllers
・NIM Bin power supply, Counter/timer, MCA, Current amp., etc.
・Timing circuit supplying a trigger signal synchronized with the　frequency of the storage ring.

◆Contact

Please note that each e-mail address is followed by "@spring8.or.jp."

Kenji TAMASAKU
SPring-8 / RIKEN
1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148
Phone : +81-(0)791-58-0802　ext.3821
Fax : +81-(0)791-58-2807
e-mail : tamasaku

Femtosecond Synchronous Laser System

◆Equipment overview

X-ray pulses can be synchronized with infrared laser pulses with a wavelength of 800 nanometers from the storage ring can be used to irradiate the sample. The irradiation time can be adjusted to complete pump-probe measurements with a time-resolution of 50 picoseconds. This can be combined with various devices provided by the user.

◆Features of the Equipment

Measurements using femtosecond laser systems are only possible in Experiment Hatch 3. To extract the X-ray single pulses, use the X-ray chopper permanently installed in Experiment Hatch 2. At this time, it is possible to complete pump-probe measurements up to 9.5 kHz. In addition, for user provided equipment to be combined with this laser system, it must be brought to Experiment Hatch 3 each time. Up to now, measurements such as X-ray photoemission spectrometry, monocrystal X-ray diffraction, and 2-color X-ray magnetism measurements have been completed. Furthermore, for user provided devices, it is necessary to coordinate with the person in charge in advance.

・Femtosecond Synchronous Laser System
The titanium sapphire laser is configured with a synchronized oscillator and regenerative amplifier which uses an rf signal from the SPring-8 storage ring. The central wavelength of transmission is 800 nanometers. Please refer to the table below for the laser parameters. This laser system is permanently located on the upstream side of Experiment Hatch 2. Laser pulses are introduced through a dedicated duct in Experiment Hatch 3, which allows for pump-probe measurements. Various optical elements such as mirrors, lenses and wave plates are available for constructing the laser optical path.

	Oscillator	Regenerative Amplifier
Method	Spectra Physics Tsunami	Spectra Physics Spitfire Ace
Pulse Width	80 fs	120 fs
Repetition Frequency	84.76 MHz	1 － 10 kHz
Output	800 mW	7 W

・X-ray Chopper
The X-ray chopper is vacuum compatible. A single pulse can be extracted in the SPring-8 H mode. The extraction frequency can be selected from 9.5 kHz, 4.75 kHz and 0.95 kHz. 9.5 kHz corresponds to 22 laps around the storage ring. The number of X-ray photons per pulse is about 106. The chopper body is a titanium disk with a 140mm diameter, which allows for relatively high photon energy.

・Control Software
The laser irradiation timing and laser intensity can be controlled by commands on a Linux PC. By combining other measurement commands, delay scanning is possible.

・Literature
　Rev. Sci. Instrum. 71, (2000) 1268-1274.
　The Japanese Society for Synchrotron Radiation Research 20, (2007) 117-123.

◆Equipment accessories

The following equipment is permanently installed in this system.
・Nothing in particular

The following accessories are also available:
・Nitrogen gas spraying device (100 ~ 300 K）

◆Experiment / sample preparation

Please use a measurement method with a pump-probe measurement using a femtosecond laser system to measure steady-state conditions in advance. Also, different lasers and X-ray penetration lengths may prevent you from seeing the signal you wish to measure. Please optimize the thickness of the sample by using a thin film.

◆Experimental procedure / precautions

When beginning the measurement, the laser and X-ray pulse timing must be adjusted at the sample location.
First, with course adjustments using a high-speed detector, it is adjusted to 1 nanosecond, then afterwards, by using the sample signal, the simultaneous laser and X-ray pulses exposure times are determined.
In addition, adjustment procedures using standard samples have been established for hard X-ray photoemission spectroscopy and monocrystal X-ray diffraction.

◆Contact

玉作　賢治 (tamasaku@riken.jp)

◆List of representative treatises

”Transient quantum isolation and critical behavior in the magnetization dynamics of half-metallic manganites”
T. Pincelli, R. Cucini, A. Verna, F. Borgatti, M. Oura, K. Tamasaku, H. Osawa, T.-L. Lee, C. Schlueter, S. Gunther, C. H. Back, M. Dell’Angela, R. Ciprian, P. Orgiani, A. Petrov, F. Sirotti, V. A. Dediu, I. Bergenti, P. Graziosi, F. Miletto Granozio, Y. Tanaka, M. Taguchi, H. Daimon, J. Fujii, G. Rossi, and G. Panaccione
Physical Review B 100, (2019) 045118.
10.1103/PhysRevB.100.045118

”Picosecond Time-Resolved Hard X-ray Photoelectron Spectroscopy System at the 27-m-long Undulator Beamline BL19LXU of SPring-8”
M. Oura, H. Osawa, K. Tamasaku, K. Tanaka, T. Pincelli, J. Fujii, G. Panaccione, and Y. Tanaka
Synchrotron Radiation News 31, (2018) 36-41.
10.1080/08940886.2018.1483658