Techniques using SR: Soft x-ray angle-resolved photoemission spectroscopy (ARPES)

                                    Soft x-ray angle-integral photoemission spectroscopy (SXPS)

                                    Soft x-ray absorption spectroscopy in the total electron yield mode (SXAS)

Applications:                Electronic structural investigation of materials

Radiation source:        A planar Halbach-type undulator (Danfysik)

Magnetic field: 0.5467 T@26.5 mm of gap
Period length: 60 mm
Number of periods: 41
Total length: 2.460 m

Photon flux at sample:    1.0 x 1010 photons/s/100 mA @E/DE ~ 10,000 (designed)

Photon energy ranges:    40 – 160, 220 – 1040 eV

G#1 (600 lines/mm) 40-160 eV
G#2 (1200 lines/mm) 220-520 eV
G#3 (2400 lines/mm) 440-1040 eV

5 keV for AES electron energy

Beam sizes in simulations:                  

Two pre-focusing mirrors are available for two point focusing.
0.2 mm (H) x 0.2 mm(V) at SXPS
0.3 mm (H) x 0.1 mm(V) at ARPES

100 micron for AES electron beam spot size

Monochromator type:      Grazing incidence varied line spacing plane grating monochromator (TOYAMA)

Sample types:                  < 8 mm x 8 mm x t1 mm @ARPES for in-situ thermal treatments

                                        < 20 mm x 20 mm x t3 mm @SXPS and SXAS

Sample environment:      In the ultra high vacuum (< 2x10-10 mbar)

Beamline status:             General user service since Mar. 2011

---

Facilities in the ARPES end-station

The ARPES end-station consists of the photoelectron analysis, sample preparation, rotary sample-transfer, MBE, and SMOKE chambers. Angle-resolved (VG Scienta, R4000) electron energy analyzer is installed in the photoelectron analysis chamber with the electron gun for AES (5 keV; 100 micron spot size) and LEED optics (1 keV). The sample preparation can be carried out in the sample preparation chamber, located above the photoelectron analysis chamber, with the Ar ion sputtering gun (3 keV@ion energy), electron-bombardment heater (1400K@max.), and gas-inlet variable leak valves connected with the roughing pump. A sample could be handled on the temperature-controlled manipulator down to 40 K in near future. Rotary sample transfer system (R2P2) transfers samples between the vacuum chambers without breaking UHV. The MBE chamber consists of the effusion cell, e-beam evaporator, temperature-controlled sample manipulator (1400K@max.), and RHEED optics (15 keV@electron energy). The residual gas analyzers (100 atomic mass@max) are installed in the ARPES and MBE.

Facilities in the SXPS end-station

The SXPS station consists of the angle-integral (Thermo VG Scientific, CLAM2) electron energy analyzer and Ar ion sputtering gun (3 keV@ion energy). Samples are loaded into the UHV chamber using the magnetic linear transfer rod from the first-entry air-lock system, pumped by the turbo-molecular pump, to the XPS analysis chamber, pumped by the 500 l/s ion and titanium sublimation pumps. The residual gas analyzer (100 atomic mass@max) is also available.