BL46XU
Hard X-ray Photoelectron Spectroscopy
1. Overview
BL46XU is an undulator beamline dedicated to promote the utilization of synchrotron radiation
by industry. The light source of this beam line is a standard in-vacuum undulator in SPring-8
and optics adopts a Si (111) direct water-cooled inclined double-crystal monochromator withtunable energy range of 6-35 KeV. Two Rh-evaporated mirrors (70cm length, reflection
direction is horizontal) are placed in the most downstream part of the optics hutch to eliminate
harmonics. The mirrors also have a curvature for horizontal light focus. A Si (111) channel-cut
monochromator is placed between the monochromator and the mirrors to get incident X-ray
with fine energy resolution for hard X-ray photoemission spectroscopy. The hard X-ray
photoemission spectroscopy (HAX-PES) system at this beamline is equipped with a VGSCIENTA photoelectron energy analyzer, R-4000.

One of the advantages of HAX-PES compared to conventional photoemission spectroscopy is
its potential for bulk sensitive measurements in a precise and non-destructive manner. As weknow that the probing depths of PES are determined by the inelastic mean free paths (IMFP) of

photoelectrons within the solid. The conventional PESs (ultraviolet photoemission spectroscopyand X-ray photoemission) usually utilize radiation from He discharge tube, synchrotron
radiation as well as Al or Mg-anode X-ray tube with energy range of several-ten to severalhundred eV. Their obtained data are strongly dependent on the surface condition of the sample
because detection depth is shallow due to a short IMFP of photoelectrons inside the solidmaterial. Therefore, it has been difficult to observe bulk electronic states that contribute to thesolid-state properties. One of solutions for this is named depth-profiling with sputtering,
however there has been a concern about property changes during the sputtering process. The 3rd
generation synchrotron radiation of SPring-8 with undulator light source enable us to use highbrilliant (photon flux ~1011 photons/sec) hard X-ray (6-8 keV) for high excitation energy
photoemission spectroscopy. The large detection depth of several tens of nanometers (typically,as around 20 nm for 8 keV) is sufficient for the observation of bulk sensitive electronic states.
Besides standard bulk-sensitive measurements, one can also get deeper core levels as well as asurface-to-bulk profile of electronic states in angle-dependent photoemission spectroscopy
experiments where probing depth can be controlled by changing the detection angle ofphotoelectrons to the sample surface.

The aim of this course is to learn a principle of HAX-PES and gain experience of measuring
photoelectron spectra of various materials with 8 keV monochromated X-ray.

2. Beam Line PracticeOn the practices at the BL46XU, we are planning to conduct the followings.

1. Introduction of optics alignment from the ring to the HAXPES.
2. Explanation of HAX-PES and vacuum systems.
3. Sample preparation.
4. HAX-PES Measurement of Au films and depth-profiling by angle-dependent photoemission
spectroscopy experiments, and

5. Discussion about experiment and introduction of data analysis.

3. Schedule
A. First day (Sep. 30th, Friday)
1. 09:30~10:00 Introduction of optics alignment from the ring to the HAXPES;
2. 10:00~10:30 Explanation of HAX-PES and vacuum systems;
3. 10:30~12:00 Sample preparation and pumping load lock;4. 12:00~13:00 Lunch;
5. 13:00~17:30 Beam line adjustment and HAX-PES Measurement of Au films as well as
depth-profiling by angle-dependent photoemission spectroscopy experiments;

B. Second day (Oct. 1th, Saturday)
6. 09:30~12:00 continue HAX-PES Measurement of Au films as well as depth-profiling byangle-dependent photoemission spectroscopy experiments;

7. 12:00~13:00 Lunch;
8. 13:00~17:30 Discussion about experiment and introduction of data analysis.